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John S
23-10-2016, 06:03 PM
Dave, look for the head off a BOSS 1 to 5 but you will need the ram as well as that head is a really solid fixed head that doesn't suffer from the nodding and endless tramming that the rubber Bridgeports suffer from.

Best thing with the BOSS head is the quill is the ball screw. The balls run round the outside of the massive quill so no bolts and no trying to tip to one side.

This is one reason I posted in post #3 to look for one and not do the conversion. Don't know what the conversion has cost but got to be loads more than upgrading an existing CNC.

Hell for a grand you could have had my 10 x 54 CNC Beaver in fully working order with 4th axis, 30 odd BT40 toolholders. 6:1 speed increaser and 8" vise if you were prepared to strip it to get it out.

Davek0974
23-10-2016, 06:16 PM
The head from a BOSS would be nice but not seen anything from a BOSS listed for some time now, seem to be getting very rare.

Whereabouts are you BTW ? ;)

Yes i decided way back in the beginning to go ahead because I just cant fit anything bigger than a manual BP in the shop - no head room at all. Yes it cost a lot but I have had a blast doing the conversion, learnt a lot and still have a usable machine to play with.

The Quill connection I was not happy with from the outset - its a terrible weak spot, unless a much taller connection is made to the quill to spread the load - this then reduces Z travel respectively and I'm already seeing the bad side of poor Z travel and i only lost 5mm from standard!

I think there is some redemption in using the quill rack/pinion - it's the strongest method and as long as backlash is dealt with should be just as accurate.

Colin Barron
23-10-2016, 06:37 PM
Future thoughts...

Machine is working very nicely so far. However I still have big doubts about the weakest link in the system - the Z-axis drive, its a pretty tortured setup, the connection to the quill is poor being just one bolt, the block face is only around 15-20mm square where it bolts on, there is around 75mm from the quill to the ball-screw so there is a massive twisting moment acting on the joint and the ball-nut.

There is already movement visible between the nut and the quill - you can see the connecting arm twisting when nudging the ball-screw pulley by hand so it would be pretty rough under drilling or plunge-milling forces. I can see a very short life for the ball-nut as they don't like twisting moments, axial or radial but not twisting.

It was assembled with loctite but with only the one bolt I doubt that would do much.

I have a feeling it would have been better to go with the drive idea in the pictures below, the quill rack is designed to take all the Bridgeport can do, there is not much backlash and what there is could be helped with a gas-spring maybe to keep it under positive pressure.

No idea what the pinion gearing ratio is but likely something like 3" per turn so would use a bigger reduction from motor.

Just looking ahead, but as i said, I can see issues here already and thats only after a few jobs....

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19487


Hi Dave,
This company has managed to fit the Z drive on the other side of the shaft and have more mounting plate bolts. The z drive is almost at the end of the video.
https://www.youtube.com/watch?v=6b0Jf-xzE0s

Davek0974
23-10-2016, 06:57 PM
Thanks, yes I've watched that vid a few times ;) Its the same deal really, same shaft in head just different connection styles. Maybe the way to go.

Colin Barron
23-10-2016, 07:15 PM
Dave, look for the head off a BOSS 1 to 5 but you will need the ram as well as that head is a really solid fixed head that doesn't suffer from the nodding and endless tramming that the rubber Bridgeports suffer from.

Best thing with the BOSS head is the quill is the ball screw. The balls run round the outside of the massive quill so no bolts and no trying to tip to one side.

This is one reason I posted in post #3 to look for one and not do the conversion. Don't know what the conversion has cost but got to be loads more than upgrading an existing CNC.

Hell for a grand you could have had my 10 x 54 CNC Beaver in fully working order with 4th axis, 30 odd BT40 toolholders. 6:1 speed increaser and 8" vise if you were prepared to strip it to get it out.

The size and weight is why bigger machines are only a grand. For most garage workshops the 875Kg series 1 manual Bridgeport is probably bigger and heavier than they had wanted to go but they are cheap, lots of info, plenty of spares and the conversions are well documented.

Davek0974
23-10-2016, 07:21 PM
Great if you can find one i guess :)

Davek0974
24-10-2016, 12:36 PM
Thinking out loud...

With the drive to the quill rack, probably from the left side as done in the FlashCut kits etc, without measuring i think the quill pinion does 2 full turns for full travel so about 75mm/turn, with a 4:1 or maybe 5:1 belt reduction from servo to pinion shaft, would that give enough resolution/torque - the motor would only ever do 8 or 10 full revs??

I could probably make a bracket pair which could take one or two layshafts which could offer much higher reduction ratios.

Maybe even look into worm-gear reduction.

Just working things through...

Colin Barron
24-10-2016, 05:37 PM
Is there much backlash on the quill gear, i have seen a drive with a ballscrew on the front of the head.

Davek0974
24-10-2016, 05:52 PM
No the quill pinion is pretty firm. Yes the screw on the front is a popular method because its the only place you can get a direct connection to the quill, trouble is its an awkward connection and i'm not happy with it yet.

Davek0974
25-10-2016, 06:33 PM
Finally scraped up the cash for proper thrust bearings on the X & Y axes. Got Nachi P4 matched pairs from BearingBoys Ltd


I fitted them in DB or back-to-back style, seemed the best option here - the preload is taken up by the screw nut rather than the bearing retainer.

What a difference, smooth as silk now and no shims needed :)

Will measure backlash again to see what change it has made.

m_c
25-10-2016, 11:34 PM
Dave, have you get any pictures of the existing setup/quill?

Davek0974
26-10-2016, 07:18 AM
A few pics here...


194901949119489

The weak spot is the joint between the coupler and the quill - there is a flat recess milled on the quill about 15mm dia and i picked up on that face, it really needs more contact above and below the bolt but then you lose more z axis travel and thats bad enough already.

Its the little round boss on the right of this part...
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m_c
26-10-2016, 09:24 AM
How much Z travel would you lose, if you bridged between the current single bolt mounting, and the end of the quill (where you currently clamp on the second spindle bracket)?
.
If you were to bridge between the two, then you should get a stable piece to then mount the ball nut to.

Davek0974
26-10-2016, 09:53 AM
I can see where you are coming from here, nice idea and would certain strengthen it 100%.

But as always there is a negative - it would stop me being able to fit the aux spindle.

By having the support on the end of the quill when running as a normal bridgeport, I would maybe lose 12-15mm of travel - not too bad. But to allow me space to fit the aux spindle as well below it, the support would have to be that much further up the quill, probably losing 40mm + of travel permanently - this would cause big issues when doing normal work.

But it is a nice idea though.

m_c
26-10-2016, 10:10 AM
Rework the Aux spindle mount, so it attaches to the new adapter?

Davek0974
26-10-2016, 10:33 AM
It's possible, the main draw-back is the loss of the already limited Z travel when doing normal work - this is a big pain in the wotsit really. Not so bad on the aux spindle as all the tools are so short as is the work itself.

To make it really work would need the knee setting up as an axis and diverting all tool-length measurements to that axis - this would mean cutting is done on the quill but the loss of travel would not be as serious.

I still feel the quill rack is a way forwards, won't cost much to try at least.

Colin Barron
26-10-2016, 10:59 AM
Maybe a totally stupid off at a tangent idea but could you build an assembly just for that purpose on the other end of the ram, then you could leave it setup and it would not get in the way of normal milling. Sorry, did not see earlier post.

Davek0974
26-10-2016, 11:05 AM
Which purpose?

If you mean the auxiliary spindle - this is only mounted when i need it, that was the whole idea really - its a normal Bridgeport plus a high-speed engraving/milling machine when needed.

The back of the ram was looked at, but adding a full Z-axis of any rigidity would be a considerable task, the aux idea is less cost and means not swivelling the ram.

I have even seen a full linear rail Z axis mounted between the ram and the existing mill head - the user locked the quill up all the time and moved the whole head up and down. Sounds nice but to get it working would not be cheap or easy i feel.

Davek0974
26-10-2016, 07:58 PM
Quill drive idea mk1,

gives a 16:1 reduction, takes up little space, mounts to existing threaded holes on left side of head.

19498

Should allow both belts to be tightened by having only one moving shaft.

Davek0974
27-10-2016, 01:53 PM
Anyone have a video or link to some pics of a powered knee mill conversion?

Seems a lot of people rate it but i cant find any proof! http://machsupport.com/forum/Smileys/default/smiley.gif

Still deciding which way to go.

John S
27-10-2016, 02:04 PM
Quill drive idea mk1,

gives a 16:1 reduction, takes up little space, mounts to existing threaded holes on left side of head.

19498

Should allow both belts to be tightened by having only one moving shaft.

What about backlash in the rack and pinion ? ?

Davek0974
27-10-2016, 03:08 PM
What about backlash in the rack and pinion ? ?

That is my main issue, its fairly tight but will have some BL in it. I was possibly thinking of some method of applying constant up force to the quill from where the existing drive is now, not sure how or what though.

Its a pain really - so close but not there yet, i know for a fact that the existing drive will fail and probably quite soon so doing nothing is not an option.

I have been looking at powering the knee and locking the quill but i still have my doubts about the knee ways and short life etc, plus the cost - ball-screw, bigger servo and drive, hardware, probably going to run about £600 just to do the knee, more if it needs a brake to stop it falling when turned off.

Then there is the speed issue - from what i have read, the knee is slow, peck drilling is going to suck as well as a few other jobs too - V-engraving would take ages due to the thousands of up/down moves used.

Just a bit baffled as to what to do really

Davek0974
28-10-2016, 07:16 AM
This seems a pretty neat way of backlash control - its a brake cable from a motorbike, one end is mounted to quill and the other has an air cylinder on it with variable pressure. The guy that fitted it also fitted a very tidy gear reduction system in the aluminium casing on the left, 15:1 ratio, double reduction. He reports zero backlash and full quill travel :)

19502

I think on cost alone, it has to be worth a try to run via the quill rack, powering the knee at any speed is going to take some time to save up for.

Davek0974
29-10-2016, 10:20 AM
Measuring on the adaptor from the Z screw to the quill, near the quill, I have well over 0.5mm of flex - thats a bad figure as it equates to backlash at the tool, so doing nothing here is not an option.

So, looking at the options -

Power the quill via the left side of the pinion shaft, this has slop in it so will need some clever way of preloading the quill upwards - this could lead to rapid rack/pinion wear as it will need enough preload to counter cutting forces from pulling the tool downwards.

Power the knee - this is an option but will cost a lot as it needs a ball-screw, servo, drive plus full tear-down to fit it all.

Alter what i have got - looking at the picture below, is there any harm in removing the web of metal circled?? It would mean i can get a bigger connecting arm in there with much more contact below the bolt to resist the down-forces, without losing any Z travel.

19503

Davek0974
29-10-2016, 04:00 PM
After some thought I reckon the easiest option based on what i have going already is to modify the quill housing and build a better connector arm - this should give more rigidity and still maintain the full Z travel.


In the attached picture, on the left is the existing setup, on the right is my next version - as you can see, in the existing one a lot of twisting moment is placed on the bolt when the arm is pushed down (heavy lines).

In the new version, the twist is converted to an axial pull on the bolt and the force transferred to the quill body via the longer contact face below.



19505

Davek0974
30-10-2016, 05:47 PM
That was a long day!

Stripped the head, cut away the small web of cast at the bottom of the quill slot, altered the screw connector by welding on a 13mm thick bar underneath, the end of the bar was milled to the curvature of the quill before stripping, fitted up, refitted the Z drive and shimmed the connector, power head back on, motor back on, encoder back on, tested.

The connector now has an extra 25mm of contact below the quill bolt which is a massive improvement over the first attempt, this makes a big difference to the twisting effect on the quill bolt and is now far more rigid in the downward direction which is what matters.

Total backlash is now down from 0.6mm+ to 0.1mm and I also discovered that most of that backlash is caused by the BK screw block not clamping the screw correctly - this was always there but never spotted it before. I will strip that block and see whats wrong with it - either crap bearings or sleeves too short and the nut not reaching properly.

I don't think this one is getting any stiffer (ooh err!) :encouragement:
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Clive S
30-10-2016, 05:51 PM
It's always nice when a plan comes together:toot:

Davek0974
30-10-2016, 06:06 PM
It's always nice when a plan comes together:toot:

Thanks, it wouldn't have worked without removing that little web of casting though:)

Davek0974
27-11-2016, 02:26 PM
What can make the tool not follow the path correctly?

Did some work today and as seen here its clearly pulling away from the corners far too early - corner rounding?

19725

Not quite so clear here...

19724

Cutter was 2mm at 23000rpm, 1000mm/min, X&Y speed set at 3500mm/min and 350mm/s/s in motor tuning.

JAZZCNC
27-11-2016, 02:46 PM
Your getting because of constant velocity and tight radius most likely caused by low accelleration. Try setting accelration higher and see if better.

Davek0974
27-11-2016, 02:51 PM
Ok, what sort of acceleration should i be aiming for if i have a top speed of 3500mm/min and bearing in mind this is a Bridgeport with a fairly heavy table;)

JAZZCNC
27-11-2016, 02:54 PM
Ok, what sort of acceleration should i be aiming for if i have a top speed of 3500mm/min and bearing in mind this is a Bridgeport with a fairly heavy table;)

I'd up it until starts stalling motors then back it off 25%. 750s/s would be nice figure to aim for.

Davek0974
27-11-2016, 02:58 PM
Ok, i'll try upping it but it would not stall - it has some fairly big AC servo's on it and a 2:1 reduction so damage would occur first i think or drive shut-down maybe.

JAZZCNC
27-11-2016, 03:02 PM
Ok forgot you have servos But same applies really however instead of stalling you'll get position errors or drive trips.! . . . You'll know if OTT

Davek0974
27-11-2016, 03:08 PM
Ok I'll dive in tomorrow night, thats the thing with servo's - you have to set an acceleration and top speed then tune the servo drive, it takes a fair bit of time to do each axis.

Boyan Silyavski
27-11-2016, 03:46 PM
But left side corners are undercut and right side corners are overcut, from what i see. So i dont think its the acceleration. What does that tell? To me- mechanical play.

Davek0974
27-11-2016, 03:54 PM
no, the corners are "dog-boned" or "T-boned" to get a square object in there.

maximum play is 0.04mm on any axis.

Davek0974
29-11-2016, 06:49 PM
Instant improvement, same code as before, same feeds etc just the increased acceleration in motor tuning.

Nice corners, no sign of rounding at all. :friendly_wink:

At least it now works up to 1000mm/min feed rates, no idea how much beyond that as i have no job that needs it.

19737

19738

JAZZCNC
29-11-2016, 06:59 PM
But left side corners are undercut and right side corners are overcut, from what i see. So i dont think its the acceleration. What does that tell? To me- mechanical play.

That tells me you know nothing.! . .:hysterical::joker:

AndyGuid
30-11-2016, 02:01 AM
Cutter was 2mm at 23000rpm, 1000mm/min, X&Y speed set at 3500mm/min and 350mm/s/s in motor tuning.
19724


Instant improvement, same code as before, same feeds etc just the increased acceleration in motor tuning.
Nice corners, no sign of rounding at all. :friendly_wink:
At least it now works up to 1000mm/min feed rates, no idea how much beyond that as i have no job that needs it.
19738

Just to clarify please, that the only difference between the Before and After results above was an increase in acceleration in motor tuning?

That's quite amazing!

P.S. Apologies that the first damn image (Attachment 19724) keeps appearing and then disappearing from automatic display!!!

Davek0974
30-11-2016, 08:11 AM
Yep, i made a point of not changing anything else at all, just double the acceleration figure in motor tuning, verified my following errors in pid tuning then run the code. Following error did not alter which is good.

JAZZCNC
30-11-2016, 09:50 PM
Just to clarify please, that the only difference between the Before and After results above was an increase in acceleration in motor tuning?

That's quite amazing!

Andy Acceleration can make huge difference to how machine performs, not only in quality of cut but also Cycle times.

Often on Smaller jobs with lots of very short moves ie: V carving engraving setting Accelleration higher and lowering velocity can increase cycle times quite drasticly.
In daves case the cause was being set to constant velocity mode G64. Meaning the control trys to maintain constant feed rate around corners. Obviously the laws of physics come into play at some point and becomes impossible to maintain this rate around tight corners.
Simplisticly put It does this by overlapping Accelleration needed for the new move with De-accelaration of the current move and the point they meet is when corner rounding occurs.
So obviously if acceleration is low then de-acceleration must happen sooner and the point they meet is further up the road. Think of it like car with poor skinny tyres and throttle stuck on.!! You turn sooner to get around corner else you crash.!! . . Having higher acceleration is like Car with brand new wide tyres so can turn later.

If you want to follow the Tool path exactly you'd use G61 Exact stop mode. Which goes exactly from point A to B and repeats for each following move. The down side of this can be very jurky movement and pause at each start/end point. If Cam software creates Arcs with tiny little lines G61 with high feedrate can shake machine to pieces.!
To see this in action Try some G-code which doesn't have G64 at the top or change to G61. If doesn't have in code Type G61 in MDI before running.

Davek0974
03-02-2017, 09:24 AM
Hi all,

been a while since this thread :shame:

For those who don't know, my Bridgeport was rebuilt with servos and larger motor, plus i added an auxiliary high speed spindle for aluminium work. The job in hand is shown in the pictures below, 5mm Aluminium, lots of holes and intricate features. I use 2mm single-flute and 5mm single-flute carbide tools for these.

Previously, I had already built a custom mini-mill to make these (and learn CNC) and still have this (its currently up for sale but no takers yet).

My reason for adding the aux spindle to the Bridgeport was two-fold - one, to save space and two, to make more use of the very expensive Bridgeport conversion which would otherwise only see intermittent use.

Now, when doing these on the Bridgeport, I am seeing bad vibration or chatter on the tool, it appears to be vertical oscillation but tonight also suffered bad enough radial oscillation to break a 5mm tool ! When it goes into oscillation it makes you jump as its very noisy and you instantly know it will end badly either in poor finish or broken tooling. Tonight I was testing tool sent from my supplier as a "Better" option :ambivalence: this was a two-flute carbide, probably the reason for the breakage as two-flute tools need a more rigid setup.

So, something is not happy - my reservation is the spindle mount (shown below) - its canted out over to one side and although it's clamped to the quill and into an R8 collet in the main spindle, it must be allowing deflection from the cutting forces.

Ok, so I have a bad situation, is there a way forward here?

Obviously I can take the dust-sheets off the mini-mill and carry on but I just don't have the space long-term and wanted to make more use of the Bridgeport as mentioned. I really want a one-size fits all solution here.

If I run the small tooling on the BP main spindle at 3000rpm (top whack) the run time per part-set will go from about 30minutes to several hours probably - feed rates go from 900mm/min to 25mm/min so i don't think thats an option - it needs more RPM's.

What can be done here guys???

Spindle-speeders?? I have seen these but they have mixed reviews and i doubt they would like a 5mm tool much as mostly used for engraving etc.

One idea I quite like is to spin the ram on the BP around and build a custom Z-axis completely, and mount it where the BP slotting head normally sits. This could be built as heavily as desired with linear guides and a servo or stepper etc.

20574

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20576

m_c
03-02-2017, 11:45 AM
The first thing that springs to mind, is how much play is in the quill?

By bolting onto the quill the way you have, any play in the quill will be greatly magnified at the second spindle, so it's probably not taken much extra wear to go from tolerable to a problem.

Creating a new Z-axis assembly sounds like the best long term solution.

Davek0974
03-02-2017, 12:01 PM
Yes, I was working through this on the drive to work this morning ;)

There will be play, must be or it would seize, plus being umpty years old i guess there will be a measurable amount.

The setup is perfect on the 2mm tools or engraving etc so it seems somewhere between 2mm and 5mm tooling is a point where cutter force and reaction come into play and bite me in the arse.

I am leaning towards a fully custom Z axis now, this brings about its own set of issues of course -

Will have to move machine away from rear wall,
..Can't move machine away from rear wall as the head hits the roof truss,
....Will have to radically modify roof truss to make clearance,
The list goes on - sometimes i hate my garage shop.

Next is - steel or aluminium build??

I am visioning it as being just a larger version of the Z axis on my mini-mill so two flat plates with rails and a screw sandwiched between, servo motor to drive and a toothed belt?

It does not need massive rails as the biggest tool is likely to be 5-6mm max so probably the same 20mm HiWin and a 1605 screw, maybe use stuff with a pre-load this time??

The hard part is working out the connection to the rear of the ram and where to put strengthening trusses/plates etc - the rear of a BP ram is a spigot maybe 50mm tall, 110mm wide and 100mm deep with a 20mm hole central - that is all i have to mount off of.

So, something like 25mm tooling plate all round or go steel and weld etc where possible.??

m_c
03-02-2017, 12:28 PM
My thought would be to weld the BP side, as it gives you more flexibility in terms of bracing/reinforcing. You would ideally need to stress relief it before doing the final machining for the rails, to minimise any long term stability issues.

Davek0974
03-02-2017, 12:34 PM
So, welded interconnect plate, relieve, then machine square etc.

Then build the motion parts in Alu ?

Davek0974
04-02-2017, 09:26 AM
Hmmm,

Just been playing speeds & feeds for my single flute 5mm tool...

Manufacturer specs...
12k Rpm
2.5m DOC
1800mm/min feed - insane i think?

My previous settings...
12k rpm
2.5mm DOC
900-1000mm/min feed

F&S Calculator recomendations...
12k rpm
1.8mm DOC
280mm/min feed - much lower ?

Maybe these lighter settings will be better?

Its only the bigger tool that has issues so does seem to be a stress problem, I will also attach a bungee cord to the head to try and remove any rotational slack in the quill.

Davek0974
04-02-2017, 04:23 PM
Ok, did some tests, first was to measure slack in the z axis at the adaptor in line with the high speed spindle - I have 0.02mm vertical (with reasonable force) and 0.15mm rotational around the quill - no doubt the source of my trouble.

Left cuts in the first picture below was at the feed recommended by my S&F calculator shown in the last post, 2 passes of 1.25mm ea, top cut is with me applying pressure to the motor while cutting to remove slack, the lower cut is with it running free as normal.

Both cuts look fine, no burr on the lip and pretty much perfect.

The right cuts in the first pic show results of a single 2.5mm DOC pass, same feed rate, again with hand pressure on the top pass and free on the lower.

Both cuts are acceptable this time but they show signs of vibration on the bottom surface - this is not an issue here as this tool is a roughing tool and will cut right through on these parts.

the second pic is just a closer view of the vibration on the second cuts.

Seems I just have to back off on the fast pedal a bit and let her do her thing, plus fit a bungee cord to remove the slop.

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20589

redtom99
24-04-2017, 11:39 PM
Ok, did some tests, first was to measure slack in the z axis at the adaptor in line with the high speed spindle - I have 0.02mm vertical (with reasonable force) and 0.15mm rotational around the quill - no doubt the source of my trouble.

Left cuts in the first picture below was at the feed recommended by my S&F calculator shown in the last post, 2 passes of 1.25mm ea, top cut is with me applying pressure to the motor while cutting to remove slack, the lower cut is with it running free as normal.

Both cuts look fine, no burr on the lip and pretty much perfect.

The right cuts in the first pic show results of a single 2.5mm DOC pass, same feed rate, again with hand pressure on the top pass and free on the lower.

Both cuts are acceptable this time but they show signs of vibration on the bottom surface - this is not an issue here as this tool is a roughing tool and will cut right through on these parts.

the second pic is just a closer view of the vibration on the second cuts.

Seems I just have to back off on the fast pedal a bit and let her do her thing, plus fit a bungee cord to remove the slop.

20590

20589

Davek0974
20-01-2018, 05:42 PM
Started modifying my conversion - I am powering the knee with a servo so i can send it tool length offsets, this will give me full Z travel with any length tool, hopefully.

Got the motor mount fitted today, hopefully get the limits and home switch fitted tomorrow:)

23631

Davek0974
21-01-2018, 02:35 PM
Got the limits and home switch fitted today, moving switches and fixed cams so I could do it all with two switches :)
Top switch is limit and bottom is home.

23640

had to alter my plan of homing to top as with the vise fitted the bed will crash...

23641

All the way down, a lot of cranking....

23642

Wired the limit switch into the loop, just the home to take back to cabinet...

23643

Davek0974
22-01-2018, 08:20 PM
I'd forgotten how busy it was in the cabinet :)

http://davekearley.co.uk/wp-content/uploads/2018/01/IMG_2069.jpg

The knee axis servo drive will have go on the right-side wall i think.

Hopefully get the drive temporarily fitted tomorrow and powered up the day after.

Davek0974
23-01-2018, 07:32 PM
Ok, got it wired and powered up.

Little snag to start with, i'm a bit rusty here....

When you take Mach out of reset, the servo starts creeping without command, anyone give a pointer as to where i start digging??

It does not creep for long as you get an ePid fault.

Thanks :)

m_c
23-01-2018, 07:48 PM
It sounds like the drive is enabled, but not under closed loop control, so it's creeping until a following error gets triggered.

The drive shouldn't be getting enabled until the servo loop is active, and able to control things.

Davek0974
23-01-2018, 07:57 PM
Hmm, I followed the same wiring style as the other axes, the drives all enable together from one signal.

Is that the loop between the servo and controller?

Maybe check the connections in the servo cable, that was a pre-made one that came with the motor and controller.

m_c
23-01-2018, 08:00 PM
Is the +/-10 connected correctly, and the drive configured to use the correct analogue input?
And is the CSMIO configured to use the correct channel?

Davek0974
23-01-2018, 08:12 PM
AFIK yes, i'll double-check the setup tomorrow night.

I'm setting up as the C axis or channel 5 on the CSMIO.

I'll try disconnecting the -10/0/10v lines to see if creeps on its own.

Dave

Davek0974
23-01-2018, 10:25 PM
Is the +/-10 connected correctly, and the drive configured to use the correct analogue input?
And is the CSMIO configured to use the correct channel?

Kudos to you - i had the encoder on C axis but analogue on A axis :)

Its running now, needs more tuning as it oscillates when it stops after homing.

Not sure what axis is best, the 2010 screen set seems to be set for XYZA but a good friend advised C axis was more aligned with the Z axis.

At least its alive :)

Chaz
24-01-2018, 04:43 PM
Ok, got it wired and powered up.

Little snag to start with, i'm a bit rusty here....

When you take Mach out of reset, the servo starts creeping without command, anyone give a pointer as to where i start digging??

It does not creep for long as you get an ePid fault.

Thanks :)

Enable 'HV Enable' in Mach3 CS Labs plugin. Use the output to drive a relay that enables your drives.

If E Stop or limit is hit, HV Enable will go away and by default your drives will dead stop (remove enable from them). This is what I do on Thor and I have done on other conversions.

Chaz
24-01-2018, 04:44 PM
Page 39 of the current CS Labs IP-A manual .....

Davek0974
24-01-2018, 04:49 PM
Thanks, I use a supply line e-stop Pilz safety relay and main contactor and safety circuit, its totally separate from the controller for extra safety. It kills power to all drives and the spindle in use but leaves the controller and PC active.

Its running now though.

Chaz
24-01-2018, 04:52 PM
Thanks, I use a supply line e-stop Pilz safety relay and main contactor and safety circuit, its totally separate from the controller for extra safety. It kills power to all drives and the spindle in use but leaves the controller and PC active.

Its running now though.

Problem is that the drives will creep unless you can find the bias sweet spot on the drives.

Davek0974
24-01-2018, 07:01 PM
All drives now steady and happy. :)

Just takes a bit of fiddling in setup

Gone for a relaxed speed - no point in thrashing the bevels etc.

Did an auto-set on the steps per, preliminary accuracy tests seem to show repeatability of -0/+0.02mm which think is pretty good for an uncompensated heavy knee. I could only test over 50mm as thats all my DTI will do so no idea yet what a long shift will do but most tools are within 100mm of each other so shouldn't be an issue i think.

Can move on to macro tweaking now.

Davek0974
25-01-2018, 09:03 PM
M6Start macro sorted, it works really well using measuring tools instead of real tools, I'll give it a go on a real job at the weekend once i've finished testing etc.

Its a most impressive add-on, she now has 350mm of clearance on the bed :)

Chaz
25-01-2018, 09:25 PM
Congrats, any vids?

Davek0974
25-01-2018, 10:07 PM
Thanks, hope to get a vid or two at the weekend - evenings are just too short :)

Just need to iron out a bug in the index homing, might be noise from the rough lash-up i'm using or may need to move the home switch a little.

Davek0974
28-01-2018, 03:20 PM
Congrats, any vids?

Here you go - bit rough as hard to video while pushing buttons :)

https://youtu.be/npuQk2Ao7UY

Also tested my homing accuracy...
https://youtu.be/55VjHRgzt9s
https://youtu.be/SUt1NiHZYIg
https://youtu.be/fLXJXyGhipw
https://youtu.be/sGrpzJVhkSk

Can't ask for better i think :)

Chaz
28-01-2018, 04:43 PM
Nice, do you have a high speed spindle fit to the machine too? If so, any pics of the mounting please? I have a friend that will be interested to do the same.

Davek0974
28-01-2018, 05:38 PM
Nice, do you have a high speed spindle fit to the machine too? If so, any pics of the mounting please? I have a friend that will be interested to do the same.

Here you go...
http://www.machsupport.com/forum/index.php/topic,32513.500.html

Chaz
28-01-2018, 06:01 PM
Here you go...
http://www.machsupport.com/forum/index.php/topic,32513.500.html

Thanks

scubatricky
20-02-2018, 11:52 AM
G84 is rigid tap cycle.

You should have bought one of these.

http://www.stevenson-engineers.co.uk/files/4axis%20mill.jpg


£450 landed in UK.

No computer, no monitor, no windows license, no Mach licence, No CSIO box of tricks.

Does rigid tapping, tool changer, pendant, all built in.

These are going to be a game changer in the future.

Link to seller?

Davek0974
20-02-2018, 02:54 PM
Link to seller?

http://www.cncmakers.com/cnc/controllers/CNC_Controllers_for_Milling/

;)

Davek0974
23-02-2018, 01:43 PM
The old girl is now sporting a QC30 spindle with BT30 drawbar :)

Better tool position and one step nearer to an ATC.

23806

JAZZCNC
23-02-2018, 03:42 PM
Link to seller?

Sadly my old mate John S is no longer with us but this was the place he got one from. Not sure they still have same model.

https://www.aliexpress.com/store/group/CNC-Controller/324577_212162836.html

Muzzer
23-02-2018, 11:33 PM
I've got one of these and it's been controlling my Shizuoka 3 axis machine for the last 6 months or so. It seems to do most stuff you'd want but the Chinglish is too strong to understand in many places - it's just machine translated. It's not a bad solution but there are some areas I've just given up on. There are only so many hundred hours you can spend trying to figure stuff out.

I'm going to remove it from my main CNC machine and use it instead on my Bridgeport conversion. For the main machine I've just bought a Centroid Acorn. Didn't think I'd go this way but I really don't fancy the investment of time required to implement Linuxcnc but the Newker controller isn't working out for me.

I found 2 companies that seem to sell the exact same product. As ever, it's not clear who designed it and who manufactures it but they are different entities.

Newker (http://www.newker-cnc.com/en/tf_product.asp?ln=0) is the brand I bought. The 4 axis mid range product is the 990MDb (M means milling, T means turning). I bought mine in China when I was there and brought it back myself. I paid about £350. That's not bad value....

Newkye (http://www.newkye.com/h-pr--0_573_1.html) is the other place. The manuals are identical and so are the products, so not much to choose between them.

There are some videos of the machine and controller in use on my YT channel.


https://www.youtube.com/channel/UCo5vJdD8q3xQ0xCrZfi9dIA/videos?view_as=subscriber

Murray

If you fancy a stab at the Baidu Chinglish Challenge, follow the link to the manual (https://pan.baidu.com/s/1qXUP1NI).

Chaz
09-07-2018, 11:08 PM
Latest on this? I'm now looking for a 'CNC' Bridgeport type machine. Whilst I have Thor, Id like something more suitable for cutting harder metals.

Davek0974
10-07-2018, 07:13 AM
Latest is that she is still munching metal :)

If asked, would i recommend anyone to convert?? The answer is no, the cost benefit is not there, I have spent probably around £8-9k on this now and at the end of the day its still a Bridgeport.

If you have the space, I would go for a VMC any time, even an old one. I do not have room or power for anything bigger so that was my reasoning to convert the Bridgy, but its not ideal - i can put the head out of tram easily, you still have to take "Bridgeport" style cuts so no hogging hard steel with big tools, you have to convert the knee to regain decent Z travel, it needs a servo drive spindle but that needs a lot of kW, and so on.

But it is capable of doing stunning things when compared to a manual machine :)

Chaz
10-07-2018, 01:32 PM
Latest is that she is still munching metal :)

If asked, would i recommend anyone to convert?? The answer is no, the cost benefit is not there, I have spent probably around £8-9k on this now and at the end of the day its still a Bridgeport.

If you have the space, I would go for a VMC any time, even an old one. I do not have room or power for anything bigger so that was my reasoning to convert the Bridgy, but its not ideal - i can put the head out of tram easily, you still have to take "Bridgeport" style cuts so no hogging hard steel with big tools, you have to convert the knee to regain decent Z travel, it needs a servo drive spindle but that needs a lot of kW, and so on.

But it is capable of doing stunning things when compared to a manual machine :)

Thanks. My limit is 2.1m roof (perhaps another 150mm if I remove the sheet cover) and then power (60A if I upgrade my breaker, single phase).

Finding a small VMC seems impossible ....

Chaz
10-07-2018, 01:52 PM
Would you say that the Universal 2S mill (or similar) has the same limitations?

Chaz
10-07-2018, 02:06 PM
And, what about something like this?

https://www.ebay.co.uk/itm/CNC-Milling-Machine-Parkson-M1250-with-3-Axis-Heidenhain-TNC-155-Control/323295632554?hash=item4b45ebdcaa:g:prgAAOSwyGBa8Gq n&autorefresh=true

Davek0974
10-07-2018, 02:34 PM
Yes headroom is the other big issue with me too, 6'6" max :(

At least you have some power - i'm limited to 32A without major wiring :(

I'm not familiar with the Parkson you linked but it looks sturdy, 40 taper is good, speeds are a little slow so better suited to steel than aluminium cutting but depends what you need really - looks a heavy machine and without all the flexible head nod & tilt should be useful.

Muzzer
11-07-2018, 08:44 PM
Seems a lot of money for an old dog. Can't imagine (m)any businesses paying that for it - if anything fails on it, the thing is scrap - you'd never get parts for it. I'd suggest it's not worth much more than the cost of delivery. A machine that is over 15-20 years old is pretty much scrap due to the controller and electronics being obsolete. No sensible business would waste their money on something that could die at any moment. But that's ideal for the likes of us who can fit modern hobby grade drivers, a Chinese controller etc and get machining.

Machines this size are usually cheaper than ones that will fit in a garage workshop. It's rather like Transit vans costing more than 7.5t lorries - they are easier to use, service, repair and store etc.

I got an "old" Shizuoka from ebay for £1k (weighs 3 tonnes). I probably paid over the odds for it but it was in really nice condition. I've found most of the bearings etc are actually standard sizes so it's been easy to service and the components are very nice quality. Cuts really nicely (https://www.youtube.com/watch?v=U8gvfcMq1hA&t=305s).

I'd wait for something in better shape and / or smaller.

Chaz
11-07-2018, 08:57 PM
Seems a lot of money for an old dog. Can't imagine (m)any businesses paying that for it - if anything fails on it, the thing is scrap - you'd never get parts for it. I'd suggest it's not worth much more than the cost of delivery. A machine that is over 15-20 years old is pretty much scrap due to the controller and electronics being obsolete. No sensible business would waste their money on something that could die at any moment. But that's ideal for the likes of us who can fit modern hobby grade drivers, a Chinese controller etc and get machining.

Machines this size are usually cheaper than ones that will fit in a garage workshop. It's rather like Transit vans costing more than 7.5t lorries - they are easier to use, service, repair and store etc.

I got an "old" Shizuoka from ebay for £1k (weighs 3 tonnes). I probably paid over the odds for it but it was in really nice condition. I've found most of the bearings etc are actually standard sizes so it's been easy to service and the components are very nice quality. Cuts really nicely (https://www.youtube.com/watch?v=U8gvfcMq1hA&t=305s).

I'd wait for something in better shape and / or smaller.

Nice. Yours looks like a Bridgeport. Centroid too, lovely.

Chaz
11-07-2018, 09:02 PM
What do you think of these? Three on eBay, one is a scam, same pics as another. 1800 to 3000 gbp.

https://auction.newengland.co.uk/lots/bridgeport-2s-universal-milling-machine-2

Muzzer
11-07-2018, 09:06 PM
Yes it’s a bit like a giant BP. Main downside is that it is a knee mill so has only 6” quill movement. Bed mills are better but tend to be called VMC and cost a lot more. I had a Chinese controller before the Centroid. Probably better overall but couldn’t understand the manual. With a modern controller and adaptive tool paths these machines can fairly fly.

Chaz
11-07-2018, 09:10 PM
I actually measured my roof height. 2340mm. An interact 2 is 2350 without drawbar.

Muzzer
11-07-2018, 09:45 PM
What do you think of these? Three on eBay, one is a scam, same pics as another. 1800 to 3000 gbp.

https://auction.newengland.co.uk/lots/bridgeport-2s-universal-milling-machine-2

It claims to be a "universal" machine but a true universal machine would have a table that pivots. It's actually a heavy horizontal mill with a Bridgeport vertical (quill) head. The table feeds will be mechanical and hard to convert to servo.

Better to get an old-ish pukka CNC machine and upgrade the controls. You'd have your work cut out converting those to CNC. Imagine trying to change them over to ballscrews - or the backlash if you didn't.

Chaz
11-07-2018, 09:46 PM
It claims to be a "universal" machine but a true universal machine would have a table that pivots. It's actually a heavy horizontal mill with a Bridgeport vertical (quill) head. The table feeds will be mechanical and hard to convert to servo.

Better to get an old-ish pukka CNC machine and upgrade the controls. You'd have your work cut out converting those to CNC. Imagine trying to change them over to ballscrews - or the backlash if you didn't.

Thanks, if I can find a machine that fits under my roof, Ill go for it. Willing to pay decent money for a good machine that I can work with.

Chaz
11-07-2018, 09:52 PM
Anything here worth looking at?

http://www.traceymachinery.co.uk/milling.htm

The low profile machine seems reasonable however they have no ballscrews etc, so possibly not worth doing.

Muzzer
11-07-2018, 09:52 PM
Yes, got to be worth waiting for the right one. Buy in haste, repent at leisure etc. If you buy a heavy old dog you will be stuck with a money / effort pit.

The Shizuoka didn't sell for the starting price so I contacted the seller and suggested something more workable and he went with it.

I've seen people make a hole in the roof to make room for a taller machine.....

Chaz
11-07-2018, 09:53 PM
Yes, got to be worth waiting for the right one. Buy in haste, repent at leisure etc. If you buy a heavy old dog you will be stuck with a money / effort pit.

The Shizuoka didn't sell for the starting price so I contacted the seller and suggested something more workable and he went with it.

I've seen people make a hole in the roof to make room for a taller machine.....

Rented house :-( Otherwise Id have no problem 'fixing' the roof.

Muzzer
11-07-2018, 10:01 PM
As John says, converting a Bridgeport isn't really the best way to go. I'm also part way through doing one myself (I was doing it when I had the accident with the mouse on ebay) and their construction is nothing like a pukka machine. Having said that, there are quite a few BP-type CNC machines that were made as CNC from new, not just the Interact type. Get one of those with ballscrews, servos etc and fit a modern controller.

Chaz
11-07-2018, 10:06 PM
As John says, converting a Bridgeport isn't really the best way to go. I'm also part way through doing one myself (I was doing it when I had the accident with the mouse on ebay) and their construction is nothing like a pukka machine. Having said that, there are quite a few BP-type CNC machines that were made as CNC from new, not just the Interact type. Get one of those with ballscrews, servos etc and fit a modern controller.

Thanks, how do I know which ones these are? I dont have the experience / knowledge? Is anything previously 'cnced' worth looking at?

Muzzer
11-07-2018, 10:11 PM
I would say if it's been fitted with servos and a CNC controller from new, it's got to be a good candidate. Could be worn out of course but a lot of the work will have been done for you even then. If you spot one of these with an old controller, it may be a good price and not hard to update. The X and Y servos (and belt drive covers) are easy to spot. If it's only 2 axis, you can do the Z axis yourself.

Chaz
11-07-2018, 10:13 PM
I would say if it's been fitted with servos and a CNC controller from new, it's got to be a good candidate. Could be worn out of course but a lot of the work will have been done for you even then. If you spot one of these with an old controller, it may be a good price and not hard to update. The X and Y servos (and belt drive covers) are easy to spot. If it's only 2 axis, you can do the Z axis yourself.

Thanks, have seen a DIY solution for Z where the machines are 2 axis only. One of these (bridgeport or clone), worth looking at then?

Ive got Thor for aluminium but would like something for steels or larger work area.

Chaz
11-07-2018, 10:13 PM
This is perfect but cant get a response from the seller - https://london.craigslist.co.uk/tld/d/excel-pinnacle-cnc-vertical/6611374089.html

Muzzer
11-07-2018, 10:19 PM
Generally on a quill machine the Z axis is done by driving the quill through a yoke attached where the feed stop used to be.

Have a look at what I've been doing - some CAD models here https://mightyshiz.blogspot.com/2018/04/bridgeport-cnc-conversion-z-axis.html

Chaz
11-07-2018, 10:22 PM
Generally on a quill machine the Z axis is done by driving the quill through a yoke attached where the feed stop used to be.

Have a look at what I've been doing - some CAD models here https://mightyshiz.blogspot.com/2018/04/bridgeport-cnc-conversion-z-axis.html

Thanks, appreciate sharing this.

Muzzer
11-07-2018, 10:24 PM
This is perfect but cant get a response from the seller - https://london.craigslist.co.uk/tld/d/excel-pinnacle-cnc-vertical/6611374089.html

That looks pretty nice. Seems remarkably cheap. If it is all there, sounds ideal. Even if it's not working it might be worth it.

Chaz
11-07-2018, 10:28 PM
Id buy this but its too tall and probably needs more power than I can provide.

https://www.ebay.co.uk/itm/Bridgeport-Interact-520-Vertical-Machining-Centre/223007272477?_trkparms=aid%3D222007%26algo%3DSIM.M BE%26ao%3D2%26asc%3D49129%26meid%3D4b95aa9d00d3489 2916c366172a4125a%26pid%3D100005%26rk%3D6%26rkt%3D 12%26sd%3D292559395898%26itm%3D223007272477&_trksid=p2047675.c100005.m1851

Muzzer
11-07-2018, 10:38 PM
Nice to have full enclosure! When you run full coolant and decent toolpaths, you get stuff everywhere.

There is also a Taiwanese VMC on ebay similar price, possibly better quality and condition, less well known.

You would run these off a VFD. Usually only the spindle needs 3 phase and you can run the coolant off single phase with a motor run cap to create the 3rd phase. The other stuff in the cabinet can usually be rewired for single phase without too much buggerage. And if you need to restrict the max power draw, you can change the VFD parameters or worst case get another VFD where you can do that. If you are drawing 10HP you will be shifting some serious swarf, so dialling it back to a few kW won't be a big issue.

Chaz
11-07-2018, 10:47 PM
Nice to have full enclosure! When you run full coolant and decent toolpaths, you get stuff everywhere.

There is also a Taiwanese VMC on ebay similar price, possibly better quality and condition, less well known.

You would run these off a VFD. Usually only the spindle needs 3 phase and you can run the coolant off single phase with a motor run cap to create the 3rd phase. The other stuff in the cabinet can usually be rewired for single phase without too much buggerage. And if you need to restrict the max power draw, you can change the VFD parameters or worst case get another VFD where you can do that. If you are drawing 10HP you will be shifting some serious swarf, so dialling it back to a few kW won't be a big issue.

Yep. Are you talking of this machine? I cant find any specs for it ... https://www.ebay.co.uk/itm/TRYAX-B5AC-milling-machine-CENTROID-M400-CONTROL-CNC-VMC-BT40-16-TOOL-CHANGE/183309395513?hash=item2aae176639:g:BZkAAOSwivNbO2f M

There is also this, no specs that I can find - https://www.gumtree.com/p/other-power-tools/rambo-powercentre-5v-cnc-turret-milling-machine/1303226159?srn=true

Muzzer
11-07-2018, 10:55 PM
I was talking of this but now I look again it's the size of a bus. https://ebay.co.uk/itm/DAH-LIH-MCV-1020B-Vertical-Machining-Centre/173374707281?_trkparms=aid%3D222007%26algo%3DSIM.M BE%26ao%3D2%26asc%3D49130%26meid%3Dfe211b30de48457 797e94fe9f1400ad2%26pid%3D100005%26rk%3D6%26rkt%3D 12%26sd%3D223007272477%26itm%3D173374707281&_trksid=p2047675.c100005.m1851

The second one looks like a classical Bridgeport based machine but a proper CNC system from new. Might be OK but has only 5" quill movement and no enclosure(!).

Quite a few nice looking VMCs on Craigslist around the £5-6k. Didn't know Craigslist had become so established over here. It's the default marketplace over in Canada / US - must keep an eye on it now I'm back in UK.....

Muzzer
11-07-2018, 11:01 PM
That Tyrax looks pretty nice but as a non-runner the price seems a bit high. Perhaps you should offer half of that and see if they bite. They obviously don't think it's worth fixing it themselves...

The Centroid controller should be OK to work with. The issues are likely to be with the spindle and drive (at least). Could be a risk hence don't offer too much. Who's going to pay £3k for it?

Chaz
11-07-2018, 11:05 PM
I was talking of this but now I look again it's the size of a bus. https://ebay.co.uk/itm/DAH-LIH-MCV-1020B-Vertical-Machining-Centre/173374707281?_trkparms=aid%3D222007%26algo%3DSIM.M BE%26ao%3D2%26asc%3D49130%26meid%3Dfe211b30de48457 797e94fe9f1400ad2%26pid%3D100005%26rk%3D6%26rkt%3D 12%26sd%3D223007272477%26itm%3D173374707281&_trksid=p2047675.c100005.m1851

The second one looks like a classical Bridgeport based machine but a proper CNC system from new. Might be OK but has only 5" quill movement and no enclosure(!).

Quite a few nice looking VMCs on Craigslist around the £5-6k. Didn't know Craigslist had become so established over here. It's the default marketplace over in Canada / US - must keep an eye on it now I'm back in UK.....

Yep, but many scams on there ..... perhaps most.

Chaz
11-07-2018, 11:06 PM
That Tyrax looks pretty nice but as a non-runner the price seems a bit high. Perhaps you should offer half of that and see if they bite. They obviously don't think it's worth fixing it themselves...

The Centroid controller should be OK to work with. The issues are likely to be with the spindle and drive (at least). Could be a risk hence don't offer too much. Who's going to pay £3k for it?

It does seem high however the machine looks fairly new. There are 2 bids on it already (lets assume they are real) ..... suppose Id pay £3K for it if the spindle wasnt too difficult (expensive) to fix or replace. Even putting on a smaller spindle if possible will work.

Chaz
11-07-2018, 11:08 PM
Might not be the same machine but they are large.

Anyone want to co rent some workshop space in West London?

https://www.aptint.com/en/used-second-hand-machinery/vertical-machining-centers/dahlih-mcv-1020-cnc-x-1220-y-510-z-560mm_3157

Davek0974
12-07-2018, 09:01 AM
I was looking at those machines too ;) theres some good stuff on there at present.

The worst part with a BP conversion is the Z axis/quill drive - it has to be canted out in front of the quill and all the force must go through a single bolt into the quill - that bolt was never made to take anything more than a quill-stop :)

As the screw is driving the quill from one side there is a lot of axial twist moment on the screw which is not good, they work but i don't know how long for.

At the end of the day with a BP you take a machine worth maybe £3k, spend £8k on it and its worth maybe £3k - there is no return value here.

Muzzer
12-07-2018, 06:50 PM
I was looking at those machines too ;) theres some good stuff on there at present.

The worst part with a BP conversion is the Z axis/quill drive - it has to be canted out in front of the quill and all the force must go through a single bolt into the quill - that bolt was never made to take anything more than a quill-stop :)

As the screw is driving the quill from one side there is a lot of axial twist moment on the screw which is not good.....

That's why I fitted a 1604 ballscrew on mine where the old quill stop / feed trip rod went. That reduces the overhang by a factor of 2 or so. Also makes for a more compact installation. Having said that, there are many professional installations that seem to last, as long as the bolt doesn't work loose.

There's an Ozzie guy who did the same thing as me although his is sort of upside down compared to mine. Worked out nicely. This vid shows the way he did it:


https://youtube.com/watch?v=RsUnoXgFtaE&t=0s&list=UUBgjJ2r9gfklBDKGlZNr5wQ&index=21


https://youtube.com/watch?v=4CXcWXZjRSw&t=0s&list=UUBgjJ2r9gfklBDKGlZNr5wQ&index=19

When you change your leadscrews over to ballscrews on a BP you get to realise how much spring there is in the yoke (in the saddle, holds the leadscrew nuts) and bearing brackets, even if you were to eliminate the backlash. Puts all the bollocks willy waving about "holding tenths" into perspective. In comparison, my Shiz is rock solid.

Davek0974
12-07-2018, 08:24 PM
Yeah seen those vids, its a nice tight job he did there. I modified my quill connector so that there is more meat below the screw - this takes the down thrust and eases the strain on the bolt a lot.

Tenths LOL, I love those discussions :) Having said that, i am really pleased how accurate my old girl is, plenty for my needs. Lately i had need to asses my probing accuracy, its only a basic probe with the three-point contact setup but i get repeatability of around +/-0.03mm which i think is pretty good for a conversion.

All good fun :)

Colin Barron
14-07-2018, 09:23 AM
I was looking at those machines too ;) theres some good stuff on there at present.

The worst part with a BP conversion is the Z axis/quill drive - it has to be canted out in front of the quill and all the force must go through a single bolt into the quill - that bolt was never made to take anything more than a quill-stop :)

As the screw is driving the quill from one side there is a lot of axial twist moment on the screw which is not good, they work but i don't know how long for.

At the end of the day with a BP you take a machine worth maybe £3k, spend £8k on it and its worth maybe £3k - there is no return value here.

The return is you have an accurate machine which weighs 875Kg, has a small foot print, low current, spares are cheap second hand because so many were manufactured, many conversions have been done on Bridgeports and ballscrew drawings are available, if it breaks you can fix it.

Davek0974
14-07-2018, 09:37 AM
Of course, there is a value but you will never make money on a conversion.

Sadly the very flexibility of a Bridgeport is the downfall of a conversion - recently lost a fair bit of stock and time following a simple tool breakage, it was not working well, the homing position was off, just wrong, it took a while to discover that the small tool breakage had nodded and tilted the head by a few degrees in both axes!

It was only a small tool but must have bucked the head as it snapped, a fixed head machine with a table as big as the BP would be lovely but the height goes up due to having all the Z travel in the head not the knee and just won't fit :)

Lesson learnt - re-tram the head every time something happens!

Yes parts are plentiful, power is usable, rpm could do with being higher - currently running 1:1 3Hp motor at 4000rpm, I think she would take 5000 but the motor would not be happy so needs raising to maybe 1:1.5 ratio or so but then bottom end suffers and rigid tapping may not be possible, I was going to fit a servo drive up there but could not figure a suitable size unit that would give speed and torque needed.

Its a lovely machine though, helps even more as i spent so long using her in manual mode as well, get to know the sounds and feel of it so you can spot a CNC tool-path thats a bit over the top ;)

Chaz
14-07-2018, 04:14 PM
Any reason not to go for this?

https://www.ebay.co.uk/itm/Bridgeport-Interact-Series-1-MK2-CNC-Milling-Machine-Heidenhian-TNC150-Control/312182476751?_trkparms=aid%3D222007%26algo%3DSIM.M BE%26ao%3D2%26asc%3D49129%26meid%3D801f8d96d498480 eb9e2e158ca490469%26pid%3D100005%26rk%3D3%26rkt%3D 12%26sd%3D132696667468%26itm%3D312182476751&_trksid=p2047675.c100005.m1851

Seller indicates its 2150mm to highest point. The newer interacts are too tall.

Thanks

Davek0974
14-07-2018, 06:23 PM
Looks reasonable, what can be seen of the ways looks good, will have ball screws, my only thought is the z travel but it can be worked with.

Chaz
14-07-2018, 06:44 PM
The head on these cant be tilted over can they? Just realised, I can just about do 2150mm but the garage door is lower, fail.

Chaz
16-07-2018, 11:16 AM
A smaller Harrison 600 has popped on another forum. Worth looking at, even for some manual milling (and perhaps CNC conversion)?

V8kid
14-12-2019, 12:46 PM
Yes, done it to something similar.

https://www.youtube.com/watch?v=M_VAXZbv6hc

has cost me around £3000 in total by now but only using steppers plus the cost of the machine. £1500 for the ballscrews as I went full hog with high preload and C3 accuracy. Also went with £300 worth of angular contact bearings to suit. Would have gone servo's if funds had allowed then.

Do not sell the DRO, I find it invaluable as you want to be able to switch between cnc and manual and also helps calibrate steps per unit.

From what I read the kit ballscrews are not as good as you are made to think, hence I went with my own ballscrews.

Hi, Where did you get the ballscrews from and did it include a larger yoke?
Cheers!

Muzzer
14-12-2019, 02:09 PM
I dunno about komatias but I got mine from AliExpress, machined to my own drawings for a nominal cost, like $5 per ballscrew - that saved a lot of messing about and they did a good job. The std ballnut diameter is slightly bigger than the std leadscrew nut, so I machined my yoke out on the (Bantam) lathe. Unless your machine is in almost new condition, you may struggle to justify expensive ballscrews, as there will be slop and backlash even once the gibs are adjusted. The ballscrews account for only a part of the total.

Using an MPG means I don't need the X & Y handwheels, which (in my case) added a lot of unhelpful moment of inertia to the servos so I removed them and have a better servo response. I still have the original DRO I fitted years ago but this simply tells me how worn the machine is. If you can achieve backlash below 20-30um (0.001"), I'd say you are doing well. However, the actual accuracy will be worse when you are machining as opposed to cutting air, as there will be additional forces at play - but the willy wavers tend not to get into measuring that, as it spoils the fun.

Chaz
14-12-2019, 06:15 PM
In the end, this is what I went for and is now for sale.

https://www.ebay.co.uk/itm/Bridgeport-Interact-Series-1-Acorn-CNC-Conversion-Tooling-inc-Single-Phase/202848167050?autorefresh=true

V8kid
14-12-2019, 06:34 PM
I dunno about komatias but I got mine from AliExpress, machined to my own drawings for a nominal cost, like $5 per ballscrew - that saved a lot of messing about and they did a good job. The std ballnut diameter is slightly bigger than the std leadscrew nut, so I machined my yoke out on the (Bantam) lathe. Unless your machine is in almost new condition, you may struggle to justify expensive ballscrews, as there will be slop and backlash even once the gibs are adjusted. The ballscrews account for only a part of the total.

Using an MPG means I don't need the X & Y handwheels, which (in my case) added a lot of unhelpful moment of inertia to the servos so I removed them and have a better servo response. I still have the original DRO I fitted years ago but this simply tells me how worn the machine is. If you can achieve backlash below 20-30um (0.001"), I'd say you are doing well. However, the actual accuracy will be worse when you are machining as opposed to cutting air, as there will be additional forces at play - but the willy wavers tend not to get into measuring that, as it spoils the fun.

Thanks for the info I have already converted my Series 1 to CNC using the standard acme screws and also removed the handles 'cos I was getting fed up with getting the occasional thump. By the way I'm with you on appropriate accuracy for outlay I paid £130 for my Bridgeport as it literally had fallen off a lorry and the head casting was cracked. Another £150 in used spares got me going and I've spent another £700 on the CNC conversion. So value.

One thing that puzzles me is the wall thickness on the standard Bridgeport yolk. I can see there is enough meat to machine out from 32mm to 40 mm but there does not appear to be enough wall thickness for the securing bolts without breaking through the wall. How did you manage?

I guess I could buy a 2505 ballnut and dismantle the X axis to see better but I'm pushed for time as we are moving house in the spring so any info would be highly appreciated.

Cheers
David

Muzzer
14-12-2019, 07:27 PM
Not sure where you get the 32mm figure from. The yoke bores are designed to take bronze cylindrical leadscrew nuts, as opposed to being directly threaded. On my Series 1 BP clone, the original X&Y leadscrews were 1-1/4" ie ~32mm OD. The actual leadscrew nuts themselves were pretty much 39mm OD and the DFU2505 ballnuts are 40mm OD, so I only had to bore the yoke bores out about 1mm on their diameters.

As for fixing, there's really no need to use all 6 holes. I only fitted two M6 screws and there was enough meat for me to drill and tap the holes. If you look at the tensile load that would cause an M6 bolt to fail, you'll see that this wouldn't be the first link in the chain to break.

Here's a bit about the actual boring: https://mightyshiz.blogspot.com/2018/01/boring-out-blidgeport-yoke-for-larger.html

And fitting the thing back on the machine. Note that the Y axis ballnut may foul something (I forget - possibly the knee lift?), which required some angle grinder action on mine.
https://mightyshiz.blogspot.com/2018/01/refitting-modified-yoke-and-ballscrews.html

Murray

V8kid
16-12-2019, 02:40 PM
Not sure where you get the 32mm figure from. The yoke bores are designed to take bronze cylindrical leadscrew nuts, as opposed to being directly threaded. On my Series 1 BP clone, the original X&Y leadscrews were 1-1/4" ie ~32mm OD. The actual leadscrew nuts themselves were pretty much 39mm OD and the DFU2505 ballnuts are 40mm OD, so I only had to bore the yoke bores out about 1mm on their diameters.

As for fixing, there's really no need to use all 6 holes. I only fitted two M6 screws and there was enough meat for me to drill and tap the holes. If you look at the tensile load that would cause an M6 bolt to fail, you'll see that this wouldn't be the first link in the chain to break.

Here's a bit about the actual boring: https://mightyshiz.blogspot.com/2018/01/boring-out-blidgeport-yoke-for-larger.html

And fitting the thing back on the machine. Note that the Y axis ballnut may foul something (I forget - possibly the knee lift?), which required some angle grinder action on mine.
https://mightyshiz.blogspot.com/2018/01/refitting-modified-yoke-and-ballscrews.html

Murray

Excellent thanks Murray I appreciate the work you put into documenting that. I'll spec the end machining myself as my drive arrangements are a little different to yours and whilst I'm waiting on China Post will bore out yoke.

Yup 32mm was a mistake on my part.

Never used a faceplate before fortunately one came with my Triumph lathe so it promises to be good fun.

Cheers
David

Muzzer
16-12-2019, 06:54 PM
FYI, I used Machine Parts Store on AliExpress https://www.aliexpress.com/item/853764075.html?spm=a2g0s.9042311.0.0.27424c4dIg5u4 J
Service was good, the machining worked for me and the price was right.

Let us know how you get on!

V8kid
22-12-2019, 03:39 PM
Thanks for all the advice I have now ordered from an eBay supplier in China as I did not get any replies to my request for quotes from AliExpress and am going ahead with C7 spec 25mm ballscrews and double ballnuts. Cost was £179 inclusive of eBay fees of £24 which the vendor detailed separately and was clearly upset about!

I guess machining the yoke will be fun as in order to align the bore I will have to centre both the tailstock and headstock ends of the existing bore and I can envisage them fighting with each other for alignment. Anyhow it keeps us out the Pub.
Cheers
David

Muzzer
22-12-2019, 06:21 PM
Wasn't too difficult to set it up in my case. There was a machined surface that I bolted against the face plate and I got the bore dialled in quite accurately with a bit of care.

V8kid
10-03-2020, 04:56 PM
Whoa! Have 3 months gone by? After finally getting the house ready for sale it was time for me today to have a bit of time in the man cave and Muzzer was mostly right in that it was easy to bore out the yoke on the faceplate - here a tap and there a little tap and with patience it dialled in spot on. The original Bridgeport acme bush had a 3 thou clearance but I decided to make the ballscrew 1 thou clearance and its a nice snug fit

However I should have read Muzzer's post more carefully as his machine is slightly different to mine and sods law the casting walls on the yoke were thinner on my series1 Bridgeport making the fixing holes problematic.

The X axis was no problem as the casting thickened around the securing flange allowing 3 fixings but the Y axis was iffy. I managed to offset grind one of the ballscrew ( V hard material would not drill) fixing holes and just manage to get 2 off diametrically opposite 6x1mm fixings with a 0.5mm wall thickness on the outside but I held my breath whilst I did it.

Only have stainless fixings in stock so will have to order HT Allen screws before assembling.

Cheers and ta for the pioneering work Muzzer

Muzzer
11-03-2020, 07:01 PM
Heheh, good to hear it went well! You don't actually need a lot of screws. If you look at the yield strength of an M6 machine screw, you'd break something else before 2 of them failed.

What's next? Have you got the rest of the parts for the X and Y drives? I forget what your plan is for the Z axis - I might have to look earlier in the thread to see what you planned....

V8kid
12-03-2020, 05:18 PM
Already converted to X&Y CNC using existing Acme screws and Steppers on Mach4 with Ethernet smoothstepper. Works OK but..... Hoping the ballscrews will give more speed and accuracy.

For the Z axis I obtained a spare head casting and machined the front flat so I can get the ballscrew closer to the quill and extended the slot downwards so I can get 2 fixings on to the quill. Need the X&Y axis up and running to machine the necessary Z axis slipper, Not sure how well this will cope with drilling large holes may have to do that manually.

How did you reinstate the oil feeds to the yoke? For the X axis I drilled into the old bush keyway which should distribute the length of the yoke but for Y axis just put a drip onto the ballscrew at the back side. Not sure how much lube is required.

Cheers

Muzzer
14-03-2020, 10:26 AM
IIRC, there were oil pipes for each of the X and Y acme nuts and I was able to reinsert them into the ballnuts. The X can be fitted when the table is still off but I fitted the Y with the table and saddle in place (forget why) and I recall a little bit of messing about inserting the pipe into its ballnut, via the hole in the front of the knee.

Nice solution, getting a spare head casting. I wasn't impressed by the crude approach used by Elrod, South West Industries etc that relied on a Z axis yoke sticking way out from the quill to clear the features on the standard head. When combined their massive castings (you could have kept a rabbit inside the housing Elrod "designed" and supplied for his conversions), the end result is enormous and expensive - but not even very robust around the ballnut and quill.

I designed my own Z axis drive using a 16mm ballscrew that replaces the threaded feed adjustment rod. This allows a ballnut yoke with a minimal overhang and the installation is compact and neat.

Unless you plan to do a lot of heavy drilling, you don't need a big motor for the Z. As a starting point, if you ignore friction, the torque and force are related like this:
Torque x angle = force x distance where angle is number of radians in one turn (2*pi), distance is the ballscrew pitch (metres) and the torque (Nm) / force (N) are your input and output.

So for my 2Nm Leadshine closed loop stepper and 4mm ballscrew, the stall force would be ~2 x 2 x 3.14 / 0.004 = ~3000N, which is equivalent to the weight of about 300kg (or three fatties). That's a lot of force and would be a test for most ballnut installations. Any pulley reduction ratio would increase that further - in fact mine is 1.8:1, resulting in about 1/2 tonne of force.

In practice, you lose a fair bit of your motor torque along the way, especially if you don't align your ballscrew carefully, but even so, you can see that a lot of these conversions you read about are stupidly overspecified in terms of stall torque, reduction ratio etc. There's one good reason for fitting limit switches...

Keep us updated on your progress!

EDIT - missed out a factor of 2 on the left side of the fag packet sums. Answer was right, though.

Colin Barron
01-04-2020, 09:57 PM
Hi,
where did you buy your Panasonic servo motors and drives.

Chaz
01-04-2020, 10:08 PM
Hi,
where did you buy your Panasonic servo motors and drives.

Who are you asking?

Muzzer
02-04-2020, 11:58 AM
Not sure who used the Panasonic servos but in my case, I used DMM Tech servos for X and Y, as mentioned on the controller thread http://www.mycncuk.com/threads/13520-Best-cheat-Chinese-lathe-controller I was living in Vancouver at the time, so I drove over to the DMM Tech building and picked them up in person.

DMM Tech seem to me to be somewhere between hobby and industrial. No disrespect to them intended but they really aren't in the same league as Panasonic, Yaskawa etc but there again, they don't claim to be. And the pricing is an order of magnitude less. As I've spent many years myself developing similar products, I took one of mine apart and it wouldn't get through a proper design validation test - but it works fine in my workshop environment for my purposes so I'm happy.

There seems to be a Korean supplier on ebay who recycles servos, motors etc that have presumably been swapped out (preventative maintenance) after reaching their service lifetime on mainstream industrial machine tools. That seems like a good option for getting hold of good quality ("proper") gear at sensible prices. Can't recall the name, mind. Perhaps somebody here knows.

Chaz
02-04-2020, 12:05 PM
I've been using Panasonic. I tend to use a guy on ebay called GPWizard (or similar). his stock varies but can sometimes source what I need.

Chaz
02-04-2020, 12:09 PM
Not sure who used the Panasonic servos but in my case, I used DMM Tech servos for X and Y, as mentioned on the controller thread http://www.mycncuk.com/threads/13520-Best-cheat-Chinese-lathe-controller I was living in Vancouver at the time, so I drove over to the DMM Tech building and picked them up in person.

DMM Tech seem to me to be somewhere between hobby and industrial. No disrespect to them intended but they really aren't in the same league as Panasonic, Yaskawa etc but there again, they don't claim to be. And the pricing is an order of magnitude less. As I've spent many years myself developing similar products, I took one of mine apart and it wouldn't get through a proper design validation test - but it works fine in my workshop environment for my purposes so I'm happy.

There seems to be a Korean supplier on ebay who recycles servos, motors etc that have presumably been swapped out (preventative maintenance) after reaching their service lifetime on mainstream industrial machine tools. That seems like a good option for getting hold of good quality ("proper") gear at sensible prices. Can't recall the name, mind. Perhaps somebody here knows.

People's experience of DMM seems very much hit and miss. Some love them, some hate them. The Panasonics cost more but they are great bits of kit. I wish I knew how to use them better but it is what it is.

My next option/ avenue would be to look at the 'common' cheap servos from China. It might be a 'get what you pay for' but for me something like DMM, with the mixed feedback) is simply too expensive. Id either go Panasonic and know I get what I pay for, or go cheap Chinese (which many are using but I have no first hand experience yet).

JAZZCNC
02-04-2020, 12:15 PM
Hi,
where did you buy your Panasonic servo motors and drives.

I was in a thread a few weeks ago and it was pointed out to me how much Yaskawa had come down in price. You can get 750W set for around £450-500 on Ebay just search Yaskawa Sigma. I'd use these over most other makes and DMM or Delta etc don't compare to Yaskawa, esp when it comes to tuning and software. They basically tune them selfs on the fly. Go to youtube and check out the Vides and the tuning software.

Chaz
02-04-2020, 12:18 PM
I was in a thread a few weeks ago and it was pointed out to me how much Yaskawa had come down in price. You can get 750W set for around £450-500 on Ebay just search Yaskawa Sigma. I'd use these over most other makes and DMM or Delta etc don't compare to Yaskawa, esp when it comes to tuning and software. They basically tune them selfs on the fly. Go to youtube and check out the Vides and the tuning software.

A good shout. The 'premium' brands are worth it if you can afford their kit.

Colin Barron
03-04-2020, 09:24 AM
You did a very positive youtube video on the BST servos/drives, how did they perform on the machine? The 750w Yaskawa drives at £500 is that second hand.

JAZZCNC
03-04-2020, 10:07 AM
You did a very positive youtube video on the BST servos/drives, how did they perform on the machine? The 750w Yaskawa drives at £500 is that second hand.

If you are talking about the 1.8Kw then yes they worked fine, they actually ended up on a Lathe. Well 2 did the third I still have waiting for a project.
I've also got some 600W 60mm here that I may do a video on as well.

The Yaskawa where new here a link for one I just did a quick search on Ebay, if you look around you may find them cheaper. They are fluctuating in price I've noticed, obviously because of the state of the markets.!

https://www.ebay.co.uk/itm/750W-YASKAWA-AC-Servo-Motor-Driver-2-39NM-NEMA32-SGD7S-5R5A00B202-SGM7J-08AFC6S/112230166972?_trkparms=ispr%3D1&hash=item1a217071bc:g:M04AAOSwujBZyiMk&enc=AQAEAAACUBPxNw%2BVj6nta7CKEs3N0qVn9oHhNHhLam5I ZAVx7BhGtcYVeNKu4kEMSCtbpdeHlxgfynNQ1Bm9KdPoineWVP 1L6bMdvUV6fGp4rPGSmzpZ3o4DMu8LIzti4Apz7JdjYo4MnNvI SyXlHdyDekbwyoBPTB9kj%2B3tkuTopDBPt5HikndsJxV5edUz gEEteQdAXYDllXDFV2Rbp0r%2B43YcQnKcuN5AAn8DsB4TruCf 91RZeoLM3wvYqQQD%2ByWgf8QNrIyRh8rR1yMaSBJ1E8DQq0Ng 7o%2FP%2BsyuqvqPR7YVWknETeJsVrmLKuj5t1fRBy0M3nVSCu vkVt%2F3hXhqrtWQJOVNddHvzm34DDAK2CkjJYvi6GtPRpJRIP %2FYOWGSzQpzVFNCfyTbw0W1pMOfbAq3jBBMuizEvFLhNdAs7R Hh9Xdvq3D%2Bphv0tWo78ZnrFGTCCQp4t%2FxOF2GRRnCSX0Zm HkTBZD56VLY7AwnZg%2FNMO7QqHVIGdrJq6J5ve073XQ2070pW 8ZJ5Aq9o12WiuwLVKEsbZ76CCgxgWxjjbPguij2Uq3FnEMHeof PF6lgln5jnoeitav3Q4iIHi5AcX7OZTsvjs1ov0oxMXn7Kakt5 rlRi1SYJXxiBi9hPAUqpZJ8YBMvVlHg78lO7NWbY3ZhX0LfYZ% 2FjjIolouIMIK%2BpOTkjeG4k%2F18nD%2BfWpd5ggJ7E1orpJ CGWNt%2B%2BY%2BRECqt%2B5UEOWN9Atsk8Ls2akwX4%2Fs4hc eNsfkl%2F3aYeoy4%2FwbVj3V7MCY6Z6Wg1DpkV7KzpVOpw%3D&checksum=1122301669723131144d4c384a7481f7dd09cee77 dea

JAZZCNC
03-04-2020, 10:13 AM
Colin if you use servos what controller are you going to use and how do you plan to run them.? Analog or Step/Dir.

Chaz
03-04-2020, 10:19 AM
The Yaskawa stuff looks very similar to Panasonic. Look at the front panel, very similar if not the same layout. Wouldnt be surprised if there is some commonality here.

For what its worth, my Father In Law used to be in charge of one of the largest ports in the world, running all their electrical systems. Think of moving millions of tons of goods per month. They used Yaskawa variable speed drives extensively, a serious outfit.

Colin Barron
03-04-2020, 10:54 AM
I have a Denford Easiturn 3 which had old electronics which did not work and i have removed them. I then thought i would reuse the steppers and drivers or steppers and the likes of the Leadshine 882 or if new servos are a direct replacement (mechanically) then the BST servos at about £250 each looks a decent bet.
On the controller front the Chinese controllers look a better bet than the mach3 bits and pieces which look like a project in themselves. A decision must be made before the controller is purchased as i believe i must specify incremental or absolute type (whatever that means?).
I was looking at the GSK clones such as Newker http://newker-cnc.com/index.php?m=content&c=index&f=show&catid=166&l=3&id=91

JAZZCNC
03-04-2020, 11:31 AM
A decision must be made before the controller is purchased as i believe i must specify incremental or absolute type (whatever that means?).
I was looking at the GSK clones such as Newker http://newker-cnc.com/index.php?m=content&c=index&f=show&catid=166&l=3&id=91

Yes, it's a bit of a mind field with these controllers so be careful, I've been looking for Mill controllers. Make sure you read all the tech spec because some have limited memory amongst other differences like how many simultaneous axis can be used at one time.

Regards Absolute and Incremental then it relates to the Encoder type used on the Servo. The BST uses incremental encoders as do most other types of servos unless you state you want Absolute.

The difference being that with incremental when you shut down the machine, the controller has no idea where the position of the machine is when it starts back up so you have to home the machine at the start of each day. (or if the servos are powered down) Just like you do with the stepper system.

Absolute Encoders retain the position of the servo even after shutdown, they do this by having a battery attached to the cable to power the memory of the encoder. This means you don't need to home the machine on startup and the drives/encoders know at all times where the machine is located, even if after power down someone manually moves an axis. (provided the battery power doesn't fail or the encoder cable is unplugged from the motor)
There is some setup I believe to be done when first installing because the drives/motors/encoders need to be told where Zero is located etc and the controller needs to support Absolute type but after that they work just like Incremental but without the need to home on startup.

Muzzer
03-04-2020, 12:14 PM
I've not seen the "absolute bus type" (990MDCb) version of the Newker in the flesh but it sounds as if it uses some sort of serial bus to pass absolute motor positional data back to the controller and presumably also does away with the conventional step/dir signals in the process.

Must admit I'd prefer not to have to home the machine each time at power on but the feature comes at a cost. I just accept that both the Newker and the Acorn need homing each time but I'd be interested to hear how the costs for the 2 alternatives compare if you enquire with Newker. Presumably you would need to buy their motors as well as the controller itself for the system to work.

JAZZCNC
03-04-2020, 12:38 PM
I've not seen the "absolute bus type" (990MDCb) version of the Newker in the flesh but it sounds as if it uses some sort of serial bus to pass absolute motor positional data back to the controller and presumably also does away with the conventional step/dir signals in the process.

I've been in touch with Newker about Bus type Absolute setup for my VMC and the absolute controller is NEW1000 MiCb-4 series. The absolute drives are dual axis so for a lathe you'll only need one drive.

I've got the manual if anyone wants to see it but it's too large to upload to Forum so contact me directly thru PM.

Colin Barron
03-04-2020, 01:17 PM
How good are the BST servos and drives? Have you tried any other cheap servo motors/drives. Do the incremental controllers operate with stepper drives, for example the Leadshine am882?

JAZZCNC
03-04-2020, 02:25 PM
How good are the BST servos and drives? Have you tried any other cheap servo motors/drives. Do the incremental controllers operate with stepper drives, for example the Leadshine am882?

The BST servos are very good for the money they cost and well worth the price but don't be under any illusions that they are in the same league as Yaskawa or any of the leading brands because they are not. You really do get what you pay for when it comes to Servos.

Regards the controller then if it outputs Step/Dir then it doesn't matter what's on the other end ie: Steppers or Servos. it knows nothing about what's attached. All it does is send out pulses and receive feedback if your using encoders and fully closing the loop.

If you are unsure about Servos and don't need the speed they allow have you considered Closed loop stepper systems? I only use Closed steppers now on all the machines I build now and I can tell you they are much better than standard steppers. They are simple and accurate if sized correctly for the machine. They don't come with any of the issues that AC brushless servos have in that you need to tune the motors to the drives and controller etc. They also don't require the same high-frequency controller that servos need to get best from them.

The difference between servos and steppers in technical terms is quite large and much more costly. I would seriously ask my self if you need to take this route when in all probabilty Closed-loop steppers will serve you just as good with a lot less hassle and cost.!

pippin88
04-04-2020, 09:31 AM
New Yaskawa servos seem to be about two to three times the price of Delta servos.

Delta servos seem to be 1.5 to 2 times the price of the generic Chinese (e.g. BST).

I am considering 750w Delta servos for a new mill build. Possibly the newer B3 drives, a bit more expensive but look to have good features. I am encouraged by the manual in comprehensible English.

Boyan Silyavski
04-04-2020, 01:04 PM
Check DMM servos

JAZZCNC
04-04-2020, 02:47 PM
New Yaskawa servos seem to be about two to three times the price of Delta servos.

Delta servos seem to be 1.5 to 2 times the price of the generic Chinese (e.g. BST).

Not really £400 for B3 Delta's on Ebay £525 for Yaskawa and can be found cheaper. While half decent the Delta's don't compare to Yaskawa and I'd gladly pay £100 more for Yaskawa.

Boyan Silyavski
04-04-2020, 03:20 PM
Am i missing something? Why you need 750w servos on a Bridgeport. 400w will do the job

JAZZCNC
04-04-2020, 03:35 PM
Am i missing something? Why you need 750w servos on a Bridgeport. 400w will do the job

Ye, I think it was a question from someone else and it's gone off topic a bit. Nothing to do with this thread I think.

Colin Barron
05-04-2020, 10:13 AM
Colin if you use servos what controller are you going to use and how do you plan to run them.? Analog or Step/Dir.

I don't know i will need to find out. Do the cheap Chinese controllers do both methods?

Chaz
05-04-2020, 10:25 AM
I don't know i will need to find out. Do the cheap Chinese controllers do both methods?

No, not normally.

Step / Dir is common. Analog, less so.

JAZZCNC
05-04-2020, 10:26 AM
I don't know i will need to find out. Do the cheap Chinese controllers do both methods?

Can't answer that because depends how cheap your talking. If you are talking the Newker type then I think most of them have both but if you are talking the really cheap Chinese controllers then no most will only be Step/dir.

However, my main reason for asking this question was more to find out if what you plan to use will provide high enough frequency that you can get the full resolution and speed from the servos. Asking about Step/Dir was to get an idea of how hard or easy you are going to have it to set up the servos, esp if using the cheap Chinese servos which don't offer any help with motor tuning.

Colin Barron
05-04-2020, 10:28 AM
Ye, I think it was a question from someone else and it's gone off topic a bit. Nothing to do with this thread I think.

Dave who started the thread used 750w servos.on his Bridgeport

JAZZCNC
05-04-2020, 10:52 AM
To be honest, Colin if your converting a Bridge port then I would seriously consider Closed-Loop steppers because they will easily match the performance that Bridgeport limits you too. In my opinion, Servos are a costly and complicated overkill for a bridge port.

Now Stepper technology as got so much better with Digital drives and Closed-loop feedback then they are a good match for Older machines like Bridge ports.
The secret is using the correct drives and sizing the motor. The Lichuan mains-powered drives that I use with 9Nm 3 phase motors will easily handle anything a Bridgeport will throw at them and are quite a bit Cheaper than cheap Chinese servos. They are simple devices with hardly any setting up required, just Fit and use.

https://www.aliexpress.com/item/32799187522.html?spm=2114.12010612.8148356.3.3cac6 f37EbjJgf

Colin Barron
05-04-2020, 11:27 AM
On my easyiturn3 lathe it has steppers and Parker CD20/1 stepper drives, would this old tech work with one of these Newker controllers, http://newker-cnc.com/index.php?m=content&c=index&f=show&catid=166&l=3&id=91

Muzzer
05-04-2020, 12:05 PM
Dunno that one but the incremental version of the Newker would almost certainly work with an existing stepper drive / motor setup. At some point there will be a step and dir signal to tap into. Even the old analogue controllers tended to have a step / dir output from the CNC controller before the signals passed through a "positioner" that generated the +/-10V control voltage. To my mind, there's a lot to be said for retaining the existing powertrain if it all works OK.

With the Newker controllers, make sure you don't get one of the "bus" versions, as they use some sort of serial bus to pass the positional signals etc to the (servo?) drives. The basic "incremental" ones send out the standard step and dir signals.

You'll notice that the screenshot of the controller in the link shows a 990TD (lathe) controller with X and Z keypads - but a 4 axis 990MD (milling) display showing X, Y, Z & A. The power of Photoshop!

JAZZCNC
05-04-2020, 12:16 PM
With the Newker controllers, make sure you don't get one of the "bus" versions, as they use some sort of serial bus to pass the positional signals etc to the (servo?) drives. The basic "incremental" ones send out the standard step and dir signals.

I think you can only use Newker Drives with there Bus Controllers because they use their own propriety protocol.

Muzzer
05-04-2020, 04:14 PM
No, I've got a Newker 990MDCa (incremental / mill) with Leadshine and DMM Tech drives. Work fine, using step and direction. I'm suggesting to avoid the "bus" version.

JAZZCNC
05-04-2020, 06:26 PM
No, I've got a Newker 990MDCa (incremental / mill) with Leadshine and DMM Tech drives. Work fine, using step and direction. I'm suggesting to avoid the "bus" version.

Read what I put again.!

Muzzer
05-04-2020, 07:38 PM
You can read that post either way round. I'm sure you know what you meant!

JAZZCNC
05-04-2020, 08:07 PM
You can read that post either way round. I'm sure you know what you meant!

Like I said read it again. Because I don't see how it can be read any other way than it was written. "You can only use Newker drives with there BUS controller" How is that not clear.? I also gave the reason why.!!