Bridgeport Manual to CNC conversion...

I guess if i do fit the servo, adding the enc module is a no-brainer really, daft not to fit it.

The bearings are sealed and hidden completely in this motor, i could likely get some WD40 in there but no grease. My main issues with fitting it are that it will fail some time, probably when i need it, and will then need my cabinet pulled apart to change from VFD to serve drive etc.

It sort of becomes a "might as well fix it now" option i think, then i can benefit immediately from the improved speed control etc. If i sell my tapping heads they would likely fetch enough to pay for the servo drive anyway :)

Decided to exercise my minimal CAD/CAM knowledge and plunge into a slab of 15mm ally for the Y axis motor plate.

Attachment 18792

Took 44 minutes on the mini-mill, used a single 5mm tool for the whole job and pocketed all the waste out ;)

Fitted perfectly...

Attachment 18793

Seemed a better place than hanging down below I think.

Decision is now leaning towards throwing the old motor back on!
Why?
One reason was that i don't have any idea if a 1.8kw servo will be a good replacement and 1.8kw seems to be the only (affordable) size that runs to 3000rpm, also, fitting an encoder for the rigid tapping module would be a total ball-ache on a Bridgeport - there is no clear access to the spindle shaft and I wrongly thought it would use the motor encoder signals which it does not.

So, back to plan 1 until the bearings fail 100% is to use the standard motor with my VFD and use the variable mechanical speed to give me two electrically variable speed ranges that overlap.

But your motor now has half the rating of this servo RPM right? 1.8kw servo has much more usable power in all revolutions than a standard motor. And higher momentary power.

I think you are mistaken a bit. I don't understand sth. The servo has an encoder. why you need a separate encoder for the rigid tapping? The servo drive surely has output of signals so what additional encoder? Read servo drive manual and you will see. My servos for example have encoder outputs and much more. Check manual.




It will be difficult for the bearing to fail 100%. It will make noise and so but i doubt it would fail if it has some grease in it.

Its all to do with power and torque, from another forum on this setup.....

Quote..

Well the 1.5Hp induction motor with variable mechanical drive would have (basing torque on 1.2Kw)

2880RPM 0.8kW and 3.94 Nm

1440RPM 0.8Kw and 7.9 Nm

720 RPM 0.8Kw and 15.78Nm

The 1.8kW Servo would have,

3000RPM 1.8kW and 5.7Nm

1500RPM 0.9Kw and 5.7 Nm

750 RPM 0.45Kw and 5.7Nm


As you can see, I would be losing a lot of power in the lower ranges but retaining constant torque, what is needed is both torque AND power.

It can be done but i would need to fit a 3.8kW servo to match the existing motor without losing performance, this is too expensive and they only run to 2500rpm.

I have just been advised that the encoder module CAN use the motor encoder ok, as long as the motor and spindle are at 1:1 ratio.

Will refit the original motor.

Finally got the replacement Y axis screw :rolleyes: Got it fitted and got the table back on at last...
Attachment 18822

Not quite plug-n-play though - the new end bracket does not fit properly and will need machining, will have to get this done elsewhere as my mill not usable ;)
Attachment 18823Attachment 18824
Can't simply file the holes longer as the counterbores need moving too. I had to get the new bracket as the original machine had power-feeds.

Found a local company to move the bores and counter-bores on the Y axis bracket - so annoying having to get stuff done outside when it would have taken me about 15mins to do, I had to leave it most of the day, make two 30min trips and stump up £40 :(

Anyway, done now and fits nicely, also mounted the motor plate using some spacers to pick up on the bottom of the counter-bores at the top face is not flat. Had to make a shim for the bearings to give a bit of pre-load but not bind up. Next job is to turn up a spacer tube for the pulley-to-bearing gap and then fit the belt - one axis finished.

Will also be planning limit switches this weekend, metal has not arrived so can't make the X axis plate yet :(

Still got this step speed head unit with a brand new 3Hp 1425 rev motor and conversion plate, you just need a VFD to run it.
£300 to get it out of my way ?

Hang on to it a little longer, lets see if this one will survive, if not i'll be in touch ;)

Got X-axis motor plate fully fitted...

Attachment 18849

Limit switches next, Y-Axis Limits and home switches...

Attachment 18848

From the left we have Y--, Y-Home, Y++.
The home switch remains tripped once it trips so that i can home even if the switch is triggered, a home-offset value will take care of the switch position.

Then the X-axis, a bit harder this one, first idea...

Attachment 18847

From the right we have X-home then a dual-direction X-- & X++ switch. The picture is not quite right - imagine the right-hand switch is another roller type like the left one, I have one somewhere, just got to find it ;)

The only down-side I can see is that it blocks the chances of using flood coolant again as the switches are in the way of the left drain hole.

Still thinking on this one.

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I hooked the rebuilt head up to my VFD today, sounds a hell of a lot better, for some unknown reason it runs a bit warm around the top bearing plate though.

Its not quite right though yet as the vari-speed system seems to do nothing in the higher end when in back-gear, but is ok in normal gear??

Nearly got the x-axis motor fitted, once that's on I can lash-up the drive and controller and do motion testing :)

Attachment 18867

We have motion :witless: In 2 axes at least. Done some basic servo tuning, cut the top speed to 5000mm/min as 7500 was just too scary. Got homing and soft limits working nicely. Homing is silly-accurate with index-homing turned on - about +/1 0.01mm or better as far as i can measure.

Next I fitted up the Spindle VFD, expecting serious issues with my complex manual/auto speed control idea. I was totally amazed that I have perfect control of speed from 40rpm to 3000rpm within about 25rpm tolerance! It tells me to choose back-gear or high-gear and high or low speed-pulley setting depending on speed chosen by code.

The only issue it does have is that if it is set for say 100rpm in back-gear low range, and the code calls for 2000rpm in high-gear high range, it will spin up the spindle and then tell me to change gear - this cannot be done without smashing the drive.

I have all the code in SpindleSpeed.m1s - can it also be made to stop the spindle and restart it after pressing enter without wrecking the code-flow etc ??

My bench-top lash-up, well it's not a bench but the plasma-cutter but here you go :adoration:...

Attachment 18871

Going to need a pretty big cabinet.

Quote:

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Originally Posted by Davek0974

I have all the code in SpindleSpeed.m1s - can it also be made to stop the spindle and restart it after pressing enter without wrecking the code-flow etc ?

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Can't see any reason why not. Post the file your using and I'll take look.

I had a second thought last night - it's not as simple as i thought as not only does it need to stop the spindle and restart it, it has to restart it in the same direction as it was running previously because when in low range/back-gear the motor has to run in reverse.

Not so sure its possible now??

I'll get the code up though soon.

Thanks

Quote:

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Originally Posted by Davek0974

Not so sure its possible now??

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Anythings possible just changes how hard it is to achieve.!

Explain a little about how it's working now.? How do you run motor direction now directly via VFD or M3/M4.

At present, it runs via VFD and 0-10v signal from CSMIO, the motor has back-gear for speeds below 400rpm and also has a variable speed mechanical control that i am using in conjunction with the VFD to enable maximum torque to be obtained at all speeds. The VFD runs from 25Hz to 75Hz so keeps the motor in the power band.

In SpindleSpeed.m1s macro i have some code that examines the requested speed and compares the current pulley range - if it is out of range it warns me to set high/low speed on the mechanical dial and possibly set the back-gear or release it if needed.

Mach is set up with 4 pulleys.

I will go get the macro and pulley data.....

Here we go...

Spindlespeed macro
Attachment 18872

Pulleys are set in Mach as follows...
1 - 40 to 126rpm & motor reversed
2 - 127 to 366rpm & motor reversed
3 - 367 to 1031rpm
4 - 1032 to 3000rpm


So 1&2 are back-gear and 3&4 are high-gear.

I was amazed at how closely the speed was set via Mach, works really well.

VFD control ?

I currently have my fwd and rev signals wired through two relays using the built-in VFD control supply to control itself.

Is this worth it or should I bin the relays and connect the VFD ground to the CSMIO control ground and go direct from CSMIO output to VFD input?

Its a little layer of isolation but also mechanical complexity if not needed.


Safety relays....
The CSMIO manual shows a PILZ safety unit being used, I gather others are just as good? PILZ are damn expensive but other like Telemechanique items are better priced.

I gather they are used because they monitor the main control contactor/relay and also offer forced contact seperation etc internally, any other reasons? Any types to look out for?

Z-axis is coming along nicely - got all the parts machined on the mini-mill ;)

Last step is to make the link from the nut to quill.

My first idea is to plasma-cut a part from 10 or 12mm steel plate, then fit it up and weld it to original bridgeport part. This would make assembly easy as i can fit the parts up on the mill then clamp together and remove to make the weld.

Sound like a plan?
Attachment 18883

Attachment 18882

Hi Dave,

I have taken photos as part of my advert so thought I would share just to give you ideas.

Started off with a plate that I flattened and cut out holes to allow access to the tramming bolts and the quill front. Used the two steps on the front of the head as a means of alignment but found they were about 0.5mm off plain. So I have shimmed the one of the flats.

Behind the ballnut you will make out a socket cap screw that engages with the actual casting where I drilled and tapped an M8. The box above I made using some scrap piece of 6mm plate and practiced my aluminium welding.

https://lh3.googleusercontent.com/-9...717_203248.jpg


The ball nut mount is made up of two parts that sort of dove tail into each other. This part is made of mild steel and I was well chuffed to get the clearances between the parts to 0.05mm. The two parts are held together by the M8 socket cap just behind the ballnut. I could thus home the Z, undo the screw and use the quill manually.

https://lh3.googleusercontent.com/-P...717_203301.jpg


https://lh3.googleusercontent.com/-3...717_203526.jpg

The mounting plate is secured on the bottom through the old feed hole in the front using a top hat boss which allows me to not lose too much quill travel.

https://lh3.googleusercontent.com/-R...717_203723.jpg
https://lh3.googleusercontent.com/--...717_203729.jpg

On the side, since the quill powerfeed is not used any more, I have used the holes to mount a side brace. If you notice there is a small M4 screw just under the elbow of the pressure regulator, this is to tension the belt of the motor. I have built this kind of tensioner in all the axes of my machine.
https://lh3.googleusercontent.com/-P...0/DSC_0884.JPG


Yours is bound to look prettier of course, hope you got some ideas though.

Its all about function not pretty :) And that looks nicely functional, thanks for sharing.

20mm screw?

Air collet closer too?

Thanks! It is pneumatic impact wrench type drawbar in a nice package. There are plans for one on the net too. You press the green button a bit and it unscrews a specially ground R8 collet.



You may have seen I use (and sell) the repeatable Z offset ER collet chucks which makes life infinitely easier when running multiple toolchanges. Measure the tools beforehand, enter them into the tool table and swap them out when needed. plenty of videos of them on youtube (search TTS tooling).

R's

Screw is 1605

TTS looks useful, will look into that.

Threw some panel buttons into the mix today, also fitted LED's for little bling ;)

Video here...
https://youtu.be/5Yz0CloE7TA

Why do the other lights come on when press cycle start.? Presume they are Feed hold and Stop.!

Are you turning lights on using Outputs and Macro pump.?

Yes my thoughts were that when idle the Cycle start and Spindle Toggle would be active and when active the Feed-Hold and stop would be active. The logic is that the lights indicate rapidly what a possible action would be.

I could go one step further and use the lamp supply as the switch source so only the lit buttons would do anything but i think Mach has that pretty much covered anyway.

Yes, I have a small bit of code in Macropump.m1s and an output feeding a relay, the lamps run from the N/c and N/o contacts on that relay.

The macropump code checks two omelette's for run or feed-hold.

Edit..
Frigging autocorrect - that last line should read....
The macropump code checks two oemled's for run or feed-hold.

I do similair thing with the control panles on my routers but it just checks Mach led's and turns on/off outputs accordingly to whats active. I use 24V led's which the Outputs turn on/off directly.

Attachment 18900

Nice,

I'm only using the relay as the two lamp patterns are directly opposite each other so i just use both N/o and N/c on the relay. LEDs are 24v but this seemed easier and only used one output;)

The Z-axis is doing my head in :concern:

My idea of welding it together is doomed to failure I think - the original bridgeport quill stop is porous and soaked in oil, any attempt to weld it simply creates a pool of oil and crap welds. I managed to tack it up but that only got me to my next headache....

Alignment is being a bitch - I can't seem to find a position where all the parts just play nicely, there is a fair amount of stress and strain between the screw and the quill, it can be moved up and down by hand but I'm not happy with it from an engineering point of view.

Not sure how to sort this at the moment, a right PITA.

I might just bolt the two parts together and see how it goes, that will allow me to shim things here and there for alignment, seeing the one from Komatias above being held by an M8 screw makes me think this might work.

Ok, sorted it i think :chuncky:

Couldn't rest without a fix so a couple of hours fiddling and a few thin shims later we have smooth motion from top to bottom, its pretty easy to reverse-drive it by moving the quill lever :yahoo:

The bracket that holds the nut was slightly twisted and the nut hole was too tight, fixing both of those cured the problem.

Now i need to fix up some limit switches and get the motor hooked up.

Attachment 18920

Got the switches fitted and have finally achieved 3-axis motion :)

Attachment 18924

A short video showing basic path with two tool-changes...

https://youtu.be/mJUxtS997MQ

Scary stuff - she has cut her first steel :stung:

Spent the morning putting stuff back - trammed the head, fitted the vise and trammed that in, fitted a floating Z touch-plate and modified the touch-off macro so it did what i wanted.

Threw a small lump of 20mm scrap in, a duff 1/2" four-flute cutter and programmed a facing cut in Aspire of 0.5mm, seemed way slower than i would have moved if doing it manually - may not be a bad thing. It gave me a speed of 140mm/min at 650rpm

Picture below - looks worse than it is, pretty good finish as it goes considering the state of the tool etc. and dry cutting plus unknown grade of steel.

Attachment 18928

Next I tried spot-drilling four places and followed up with through-drilling with a 6mm drill, all went perfectly.

I really need to sort the speed control out though - it tells me when to put it in back-gear or high/low speed so the VFD can give me the final speed BUT it only does this when it gets the S command from the code - it shows the message on screen but the carries on cutting at the wrong speed. What i need is for it to stop the spindle and show the message, wait for me to set the right conditions and the restart the spindle and get to work.

All looks fine now. So whats next? Mist cooling, right?

Ha, I already have that built, it's fitted on the mini-mill.

The next step is to weld up a suitable control cabinet, this is needing a big cab - about 850 tall x 700 wide and 270 deep, commercial ones are +£250 in that size so will plasma cut and weld up from 3mm sheet steel parts i think.

Then i have to strip the rats-nest down and start the final build.

I've been running various cutters through HSMadvisor and it seems i've been pushing them quite hard when doing it manually - all the feeds seem very relaxed ;) I tended to run the HSS so the chips were straw coloured and the carbide insert ones just flat out and hard - dark blue chips that melted your shirt ;)

Got the control cabinet built today, absolute monster and a two-person lift :)

Attachment 18967

Fitted the mounting bars too.

Attachment 18966

Next job is to strip the test setup down and start final fitting.

Quote:

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Got the control cabinet built today, absolute monster and a two-person lift :)

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Well it will be a three person lift when you fill it:joker:

your'e not wrong there, i have all the guts temporarily mounted on a pallet top and i can just about lift it all, not quite sure how i'll lift the steel panel into the cabinet yet;)

Back to my dual-spindle attachment, yes its been done before, found two people that have done a great job and turned out some amazing stuff on them.

I was looking at a single thick clamp ,made from maybe 25-30mm alu, but this idea seems far better....

Attachment 18989

It uses a two-layer clamp, bridged in the middle firmly and then clamped on the quill plus clamped to a fixture held in a collet in the spindle. This seems like it would be very stable plus use up less of my valuable Z axis travel.

Material is probably only 15-20mm thick so i would lose no more than 20mm of travel in Z, leaving me a healthy 100mm to play with. The wide spaced clamps should also grip the high speed spindle better too.

Not sure why he has made the bottom clamp like it is at the spindle nose, I would go with a solid area and a 20mm shaft fitted for a 20mm R8 collet - the attachment would then be slid upwards into the collet and onto the quill.

Why not just get a quillmaster or a speeder? Somthing that is inline with the spindle in the firstplace.