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Ricardoco
07-09-2011, 11:47 PM
Yippee my wait is over..:dance: the new machine has been delivered:naughty:
4488

Just waiting for the ali stock now to start the conversion, Ive got some rolled ballscrews and nuts that will fit the bill for the time being, but i need these for another job so i will be purchasing some ground Ballscrews in the near future. All the design work for the conversion will be completed on V-Carve and machined with Mach3 i will upload files as and when they have been proven, with the odd video here and there.

My Initial opinion is the build quality is not as bad as i thought it would be in fact its very good, the supplier was very helpfull and it was delivered on time. :tongue: I will get some picks of the strip down as i do it.....:twisted:

Lee Roberts
08-09-2011, 01:16 AM
Look forward to following this one!

Just a thought, will you be offering a conversion kit once proven or?

.me

Ricardoco
08-09-2011, 01:44 AM
Look forward to following this one!

Just a thought, will you be offering a conversion kit once proven or?

.me


:naughty:I suspect you will.:whistling:

Ricardoco
08-09-2011, 01:49 AM
OK the first question... i will be gearing the steppers at 2.5:1 and I will be using T5 10mm pulleys to give me 0.01mm resolution per step i wonder what size is the smallest pulley available i know i can get a 10 tooth but do they go smaller?

Web Goblin
08-09-2011, 07:06 AM
I would be very surprised if you can get a pulley with less than 10 teeth. 10 teeth is the least I have ever seen anyway.

Ian

Jonathan
08-09-2011, 07:27 AM
I would advise against getting a small pulley as I heard the belt wear is greater. Also you may struggle to get enough teeth meshed on a very small pulley.

Only disadvantage I can think of with a bigger pulley is the moment of inertia is greater, but that's probably negligible on a mill.

fragger6662000
08-09-2011, 08:19 AM
I would avoid belt drive, extra complexity is extra problems. They will also limit the maximum speed of the machine if you look at my convertion or the hoss machine you would be better to follow that template. The g540 is the way to go i have used some of the drives from the uk and they are not a patch on this setup. Keling was where i go my drive and motors from.

http://www.cnczone.com/forums/benchtop_machines/118813-spg_2217-20lv_milling_drilling_machine.html

Ricardoco
08-09-2011, 01:13 PM
I would be very surprised if you can get a pulley with less than 10 teeth. 10 teeth is the least I have ever seen anyway.

Ian
Cheers Ian:smile:, Me too, In fact many of the sites I checked started at 12 teeth.


I would advise against getting a small pulley as I heard the belt wear is greater. Also you may struggle to get enough teeth meshed on a very small pulley.

Only disadvantage I can think of with a bigger pulley is the moment of inertia is greater, but that's probably negligible on a mill.

Thanks Jonathan:smile:, I did Intend to use a 10 and 25 tooth pulley to give me the ratio I needed, and going for anything smaller as you say may put too much load on the reduced number of meshed teeth. So 10 and 25 then.

So the pulleys will be as above.

For those people that are not aware of why I would like to use pulleys then let me explain.

:confused:Using 1605 ballscrews will give me a pitch of 5mm, that is to say 360 degrees in 1 rotation of spindle will advance the axis 5mm.

If i use a direct coupling stepper to screw,

The stepper will give full steps of 1.8 degrees.

360/1.8 will give me 200 steps per revolution.

5mm / 200 will give a resolution of 0.025mm per full step.

This is an odd measurement to use in my head, i have done it though..

Using a ratio of 2.5 to 1 ( 10 and 25 tooth pulleys) will give me a step resolution of 0.001mm per step.

and if i were to use half steps as the stepper is capable of doing, it would be 0.0005mm per step...

thats a fair bit of resolution/accuracy, there are however disadavantages to using pulleys.

its upto the individual who is designing/building and using the machine.

(a special thank you to i2i who educated me on this subject in the first place)

There you go clear as mud!!!!:confused:

Rick

fragger6662000
08-09-2011, 01:33 PM
Cheers Ian:smile:, Me too, In fact many of the sites I checked started at 12 teeth.



Thanks Jonathan:smile:, I did Intend to use a 10 and 25 tooth pulley to give me the ratio I needed, and going for anything smaller as you say may put too much load on the reduced number of meshed teeth. So 10 and 25 then.

So the pulleys will be as above.

For those people that are not aware of why I would like to use pulleys then let me explain.

:confused:Using 1605 ballscrews will give me a pitch of 5mm, that is to say 360 degrees in 1 rotation of spindle will advance the axis 5mm.

If i use a direct coupling stepper to screw,

The stepper will give full steps of 1.8 degrees.

360/1.8 will give me 200 steps per revolution.

5mm / 200 will give a resolution of 0.025mm per full step.

This is an odd measurement to use in my head, i have done it though..

Using a ratio of 2.5 to 1 ( 10 and 25 tooth pulleys) will give me a step resolution of 0.001mm per step.

and if i were to use half steps as the stepper is capable of doing, it would be 0.0005mm per step...

thats a fair bit of resolution/accuracy, there are however disadavantages to using pulleys.

its upto the individual who is designing/building and using the machine.

(a special thank you to i2i who educated me on this subject in the first place)

There you go clear as mud!!!!:confused:

Rick

And hurry up moderator.

But you should be using 8 / 10 mirco stepping for best performance of the motors and why are you worried about the interger as it is a cnc'd machine that will be controlling it.

As before i have done it with this machine, 0.001 res is pie in the sky, 200,000 machine tool struggle to get that with direct drive and servo's. 0.025 per step is what i run and gives me 1500mm/min rapid you would be lucky to get 700mm/min as you would be over spinning the motor and have not torque.

resolution and power work againest each other.

here a like to my Thread on cnc zone.

http://www.cnczone.com/forums/benchtop_machines/118813-spg_2217-20lv_milling_drilling_machine.html

Lee Roberts
08-09-2011, 02:35 PM
Sorry for the delay and welcome fragger!

Ricardoco
08-09-2011, 04:20 PM
And hurry up moderator.

But you should be using 8 / 10 mirco stepping for best performance of the motors and why are you worried about the interger as it is a cnc'd machine that will be controlling it.

As before i have done it with this machine, 0.001 res is pie in the sky, 200,000 machine tool struggle to get that with direct drive and servo's. 0.025 per step is what i run and gives me 1500mm/min rapid you would be lucky to get 700mm/min as you would be over spinning the motor and have not torque.

resolution and power work againest each other.

here a like to my Thread on cnc zone.

http://www.cnczone.com/forums/benchtop_machines/118813-spg_2217-20lv_milling_drilling_machine.html

Ok Hi There fragger, the steppers two x 23 & 1 x 34 from motionking, the 'integer' is for me, not the software, I design what would end up on the machine in the first place as i said "This is an odd measurement to use in my head" Now as for accuracy, wouldnt you say, that aiming for the highest accuracy you can in the begining is the correct thing to do.

I would never suggest I would get that resolution at the end of the project but if i allow the push for accuracy to become secondary to simplicity of build i would not be true to myself, and speed/feedrate well this is a hobby for me, im not in a hurry, im still one of those sad individuals that likes to sit there and watch, and i know im not the only one :wink: AM I???

Would i not get more torque with a 2.5:1 setup then?

I have read with interest the posts about this machine type on cnczone.

Pulleys are the way i would like to go as i dont like the positioning of the steppers in the other projects I have seen, they may be fine for you and make the conversion simple and speedy but that is not what im after, I have learned a lot from the conversions on cnczone but they just dont fit my requirements.

Stevie Nicks and her famous song told me all i needed to know lol

I do like the way you have mounted your x axis ballnut, that is simple effective and a touch inspired and look much more stable than the other ways i have seen.

I will follow your thread with interest and i may even use some of your ideas (giving credit of course), "if thats ok of course"

Rick
.

fragger6662000
08-09-2011, 04:25 PM
No worries


Sorry for the delay and welcome fragger!

fragger6662000
08-09-2011, 06:37 PM
No you don't get more torque, stepper motor produce most torque when stalled, as you increase the rpm the torque drops.

I know well know manufactures of encoder scale that produce an 8um pitch and you have all the american stuff.

When i built my first cnc'd x1 i was using a imperial z screw, you never need to know the interger apart from the time you enter it into the control software.

By using pulleys you get
-another source of backlash
-drive flex(belt stretch)
-reduced top speed
-side load on the screw
+ratio change
+allignment flexabilty

i tried belts on a lathe, big disapointment. now directly driven.

if we are quoting "you can lead a horse to water but cannot make it drink" I personally think your logic is flawed, if you want an additonal challenge that is far enough.

As for i am old school i like to watch it, the x1 had a rapid of 400mm/min and it got very old very quickly and that was a smaller machine.

Jonathan
08-09-2011, 07:17 PM
I don't see the point of wanting a round number. As soon as you've entered it into mach3/EMC you won't need to know about it at all. I've forgotten what the value is per step on mine...

As fragger said, you will almost certainly be using 1/4 or 1/8 micro-stepping anyway which effectively changes the value but doesn't really gain accuracy.



By using pulleys you get
-another source of backlash
-drive flex(belt stretch)
-reduced top speed
-side load on the screw


1) no, unless your pulleys are awful. Mine have not added backlash.
2) negligible from my experience.
3) What! That's impossible to judge without calculating it properly. You need to get the motor running in the optimal region of the torque/rpm curve and to do that you need to get the ratio right which, unless you're very lucky, requires pulleys.
4) Surely the bearings in the mill are going to cope with that...if not add more? I'd be more worried about the bearing on the stepper motor.

On my router I've found that generally increasing the size of the pulley on the stepper motor has increased the top speed, but of course sacrificed resolution. It's less clear cut on a milling machine as it's heavier and the coefficient of friction is greater.

Ricardoco
08-09-2011, 07:44 PM
No you don't get more torque, stepper motor produce most torque when stalled, as you increase the rpm the torque drops.

I know well know manufactures of encoder scale that produce an 8um pitch and you have all the american stuff.

When i built my first cnc'd x1 i was using a imperial z screw, you never need to know the interger apart from the time you enter it into the control software.

By using pulleys you get
-another source of backlash
-drive flex(belt stretch)
-reduced top speed
-side load on the screw
+ratio change
+allignment flexabilty

i tried belts on a lathe, big disapointment. now directly driven.

if we are quoting "you can lead a horse to water but cannot make it drink" I personally think your logic is flawed, if you want an additonal challenge that is far enough.

As for i am old school i like to watch it, the x1 had a rapid of 400mm/min and it got very old very quickly and that was a smaller machine.



:redface: I actually felt like you were telling me off then....

Well i will consider myself told shall I....:cry:

Usually people dont have to be so blunt to get the point across, Im not so stuck in my ways that im not open to suggestion, On a recent project I took a lot of advice from the members of this forum and put it into practice, that is why i participate in forums.

I dont really want to just copy you or hoss, but neither do i want to re-invent the wheel.

thats why i dont just guess at this, I've looked at several sources of information and am still looking, here is just one source.

http://www.arrickrobotics.com/pr23.html

I dont disagree with all you say, and there are sacrifices to be made using pulleys however my 260 is not direct drive, it is very accurate, as much as i need anyhow, and i really dont want the steppers hanging of the end of the axis (not sure what you would call a group of axis lol), so do you have any other suggestions?

Thanks in advance for your input.

Jonathan
08-09-2011, 07:48 PM
I forgot to mention the other big advantage of belts which is that they greatly reduce resonance problems.

The site you linked to has mentioned what I did:

'Even though the output speed is reduced by the reduction ratio, some systems will actually have their overall speed performance increased due to better use of the motor's torque curve.'

I wouldn't hesitate to use belts again - I will when I convert my lathe, though admittedly that's partly because it'll have a rotating ballnut.

Ricardoco
08-09-2011, 09:48 PM
I don't see the point of wanting a round number. As soon as you've entered it into mach3/EMC you won't need to know about it at all. I've forgotten what the value is per step on mine....

I had decided that for the way i wanted to position the steppers that belts and pulleys was the way to go and at a 2.5:1 ratio i would get that round '1' it was not a requirement i could have even gone 1:1 and still can ill just swap out the pulleys and belts if need be and i will probably forget about it as you have.

The little ratio and ballscrew tutorial I wrote down in the middle of the post was perhaps to make things easier for some people to understand as it was a source of many questions from me when i did the other conversion. Using round numbers just made it easier in my mind to see what was going on thats all..


As fragger said, you will almost certainly be using 1/4 or 1/8 micro-stepping anyway which effectively changes the value but doesn't really gain accuracy..

Shouted! :lol:

on another note what do you think of the idea of a counter balance on the Z... please dont shout your reply its only a question...:heehee:

Rick

Jonathan
08-09-2011, 10:02 PM
on another note what do you think of the idea of a counter balance on the Z... please dont shout your reply its only a question...:heehee:


I think someone on this forum is considering it / has done it...
As I'm sure you know it should improve your Z-axis feedrate, but when do you actually need a high feed there? Possibly small drills (definitely with PCBs) and maybe with 4th axis in some situations but that's about it?
You can use an 'oversize' (i.e. greater than the mass of the head) counterweight to eliminate backlash in the Z-axis.


Are you using a rotating ballnut on Z, just out of interest?

fragger6662000
08-09-2011, 10:18 PM
If you are thinking of under slinging the motors on x you will loose lots of travel.

Hope you have fun doing the machine as it is certainly a rewarding thing to do. especially when it works!

Ricardoco
08-09-2011, 10:24 PM
Are you using a rotating ballnut on Z, just out of interest?

Hmmm tell me more...

Ricardoco
08-09-2011, 10:50 PM
If you are thinking of under slinging the motors on x you will loose lots of travel.!

it will be in front i suspect, just a tad lower than the bed. although it would have been nice if i could have put it underneath without the loss of travel.


Hope you have fun doing the machine as it is certainly a rewarding thing to do.!

Likewise :tup:


especially when it works!

Well here's hoping. Needless to say i will only post what works...:rofl:

Ricardoco
09-09-2011, 01:32 AM
Well here is an idea, im sure there will be people with experience of this sort of thing.

4490

just a basic concept and yes There are covers missing for clarity...

This type of thing is what i was looking into and it all misses the y axis as well so no loss of x or y. excuse the drawing its my first google sketchup

Robin Hewitt
09-09-2011, 11:35 AM
Using a ratio of 2.5 to 1 ( 10 and 25 tooth pulleys) will give me a step resolution of 0.001mm per step.

Hi Rick

AH! Confidence truly is that feeling you get just before you understand the problem :heehee:

.001mm is one micron. Standard ball nuts give you 50 microns, shimmed gives you 20, the only way to get 1 is to use double nuts and spring them. Helps if you can hold the screws in tension with more springs. The Belleville washer is your friend. You can compensate for backlash, but you will forever expect the tool to dig in.

Ball nuts bed in, they may feel firm but you are probably pushing against the dust seals and kidding yourself. The seals can't hold it when the tool loading kicks in.

If you bolt the column to a brick wall I would suggest a 5 micron step, 200 steps/mm is optimal for accuracy and speed. Half step is good, quarter step is vaguely credible, beyond that everything gets too springy.

Getting high accuracy is more a problem of rigidity than anything else. You can't mill to 5 microns because the tool will bend, you can't skim 10 microns, it will simply ignore you. To get 5 microns your tooling needs to cut a mirror finish. IMHO 5 microns or better has to be ground.

Good luck :naughty:

Robin

Ricardoco
09-09-2011, 12:49 PM
Hi Rick

AH! Confidence truly is that feeling you get just before you understand the problem :heehee:

.001mm is one micron. Standard ball nuts give you 50 microns, shimmed gives you 20, the only way to get 1 is to use double nuts and spring them. Helps if you can hold the screws in tension with more springs. The Belleville washer is your friend. You can compensate for backlash, but you will forever expect the tool to dig in.

Ball nuts bed in, they may feel firm but you are probably pushing against the dust seals and kidding yourself. The seals can't hold it when the tool loading kicks in.

If you bolt the column to a brick wall I would suggest a 5 micron step, 200 steps/mm is optimal for accuracy and speed. Half step is good, quarter step is vaguely credible, beyond that everything gets too springy.

Getting high accuracy is more a problem of rigidity than anything else. You can't mill to 5 microns because the tool will bend, you can't skim 10 microns, it will simply ignore you. To get 5 microns your tooling needs to cut a mirror finish. IMHO 5 microns or better has to be ground.

Good luck :naughty:

Robin

Well as I said if I aim high and do the best i can with what i have its an education and im not sure it will hurt will it. I do wish in my original post i had used the work theoretical...

Rogue
09-09-2011, 05:14 PM
.001mm is one micron. Standard ball nuts give you 50 microns, shimmed gives you 20, the only way to get 1 is to use double nuts and spring them. Helps if you can hold the screws in tension with more springs. The Belleville washer is your friend.

By double nuts do you mean the "double ballnut" that somewhere like Zapp sells, or do you mean using two seperate nuts and combining them with the spring?

I've seen the latter in different places around the internet, but I didn't know if the former was simply a commercial version of the latter.

Jonathan
09-09-2011, 05:17 PM
I'm pretty sure Robin will mean two nuts sprung, hence the Belleville washers. I think the commercial versions are just shimmed. To eliminate backlash you need them to be pushed apart using a spring applying a force greater than any cutting force plus acceleration, F=ma, you anticipate.

Rogue
09-09-2011, 05:19 PM
I think someone on this forum is considering it / has done it...

I'm playing with the idea, primarily because I think it looks good, effectiveness be damned! :twisted:

On a related note, I also asked similar questions about the under-table mounting, the consensus seemed to be that it wasn't a problem. The following thread might have useful things for you: http://www.mycncuk.com/forums/showthread.php/3735-Mounting-motor-under-table

Robin Hewitt
09-09-2011, 06:17 PM
By double nuts do you mean the "double ballnut" that somewhere like Zapp sells, or do you mean using two seperate nuts and combining them with the spring?

Either, if you use a double take the shim out

i2i
09-09-2011, 06:21 PM
on another note what do you think of the idea of a counter balance on the Z...
Rick


Denford used to do this on the early triacs, they stopped it quite quickly.

Ricardoco
09-09-2011, 06:24 PM
I'm playing with the idea, primarily because I think it looks good, effectiveness be damned! :twisted:

On a related note, I also asked similar questions about the under-table mounting, the consensus seemed to be that it wasn't a problem. The following thread might have useful things for you: http://www.mycncuk.com/forums/showthread.php/3735-Mounting-motor-under-table

I will be using the Double ballnut if needed when i fit the ground Ballscrew but for now with the rolled i will use just the 1 with the ability to encorperate a double in the design..

LOL well here is the Vcarve output for the endplate for the Z with a side mounted stepper, or if prefered it can be hung on the end infact ive desinged it so you could hang it on the left rignt or even underneath,Ive not included the tensioning system yet as im still working on it. I still think it looks bodged on the end but that is just my opinion lol

4496
4497

I will make the prototypes out of a non metalic material i suspect...:smile:

Oh and ive made it incorperate the ballscrew Double A/C bearing housing as well.

Ricardoco
09-09-2011, 06:31 PM
Denford used to do this on the early triacs, they stopped it quite quickly.

Hmmmm Your not the first to tell me that, i wonder if the bell is tolling for the counter balance idea!!!!

i2i
09-09-2011, 06:52 PM
I expect the cutter needs the weight of the head to give it "balls"

Ricardoco
09-09-2011, 06:55 PM
I expect the cutter needs the weight of the head to give it "balls"

All of it!!!:surprised: thats just greedy.:heehee:

fragger6662000
10-09-2011, 12:38 PM
you don't need to counter weight this machine if the correct steppers are used.

A setup with light stepper and poor z slide ways will cause crabbing and stalling. You counter weight to reduce the crabbing of the head. counter weighting does nothing to the cutting force as the slide ways and the screw resist this not the weight of the head. It does affect the acceleration as there is a greater amount of inertia.

Ricardoco
10-09-2011, 03:29 PM
you don't need to counter weight this machine if the correct steppers are used.

A setup with light stepper and poor z slide ways will cause crabbing and stalling. You counter weight to reduce the crabbing of the head. counter weighting does nothing to the cutting force as the slide ways and the screw resist this not the weight of the head. It does affect the acceleration as there is a greater amount of inertia.

Cheers Fragger, I had seen a thread on another forum about the counterweight and threw the question out to see what everybody thought as the concept was one that i was not famillier to me , you are with the majority in thinking it is not required or even desired, In an Ideal world what stepper would you suggest ive got a 34.

Rick..

fragger6662000
10-09-2011, 10:18 PM
i used the keling kit with 900ozin on Z and 381 on the XY.

The X is rated at 900oz but the drive is only delivering 3.5 amps so i think it is 500oz.

Have you go the motors and and drives because i would recomend the kelinginc kit as the motor are low impedance and give the best performance. UK motors seams to have a lot higher impedence and poorer performance.

fragger6662000
10-09-2011, 10:23 PM
http://www.kelinginc.net/CNCNEMA23G540Package.html

sorry the z was 34 and xy 23

Jonathan
10-09-2011, 10:29 PM
i would recomend the kelinginc kit as the motor are low impedance and give the best performance. UK motors seams to have a lot higher impedence and poorer performance.

Surprising that you imply all UK motors have a high inductance. It clearly depends which you get and where. Can you link to a datasheet for the ones you have so we can compare?

Edit, actually ignore that - found it:

http://www.kelinginc.net/KL34H295-43-8B.pdf

To be fair that's quite a low inductance for that size motor. Still with a Nema 34 motor you really should be running it on a LOT more than 50 volts.

fragger6662000
10-09-2011, 10:30 PM
http://www.kelinginc.net/CNCNEMA23G540Package.html

sorry the z was 34 and xy 23

fragger6662000
10-09-2011, 10:35 PM
http://www.motioncontrolproducts.com/motors/hybrid-nema-23-stepper-motors.php?cat=1
http://www.arceurotrade.co.uk/Catalogue/Stepper-Motors/Stepper-Motors

http://www.kelinginc.net/KL23H2100-35-4B.pdf

i have not looked recently but this was what i found jan this year

Jonathan
10-09-2011, 10:46 PM
The ones at Zapp are close, but still more than Kelling. I'm surprised as I've spent ages looking for lower inductance motors, though only really Nema 23.
Either way the difference is insignificant if you're running the motor on a higher voltage with something like this:

http://www.zappautomation.co.uk/2m1180n-high-voltage-stepper-driver-p-559.html?osCsid=65b8731690f55887745669f8490a6970

Without that you'll never get a very high speed from that size motor, if you need it.

fragger6662000
10-09-2011, 10:55 PM
i would go for this if i were to running higher voltages

http://www.geckodrive.com/g201-p-31.html

i have used similar drives to the one at zap for my first project and they are Chinese in origin and my experience was not good.

Gecko are US designed and built

Jonathan
10-09-2011, 11:03 PM
You seem to be implying that just because it's not US designed and built it's not going to be any good? Maybe that's correct in some, or indeed a lot of cases but I'll bet they're getting better. I got my PM752 drivers, which are rated similarly to what you linked to and are Chinese origin, and can only highly recommend them:

http://www.zappautomation.co.uk/pm752-microstepping-driver-p-409.html?osCsid=65b8731690f55887745669f8490a6970

Still, 75v / 80V is nothing compared to the 240V driver. I think Robin Hewitt used them on his mill?

Interestingly the Gecko driver says 'Silent 20kHz PWM switching'. I'm pretty sure I can still hear 20kHz, so that would be annoying!

fragger6662000
10-09-2011, 11:14 PM
i bought 5 of the 4.2amp version and 1 failed.

I don't have an issue with chinese stuff but high voltage and currents i avoid from my previous bad experience.

Also i don't really trust anything that quotes PTP not RMS to boast there numbers. so the 5.2amp driver is only 3.7 when you get to 3.37 when you read page 9.

Ricardoco
11-09-2011, 01:48 PM
Ok here is a question that im sure could have many answers, Ive looked at a few calculators in the past but I do prefer the opinions of those than can, rather than some calculator that Could...
Im going to wake up the boxford today and cut some bittlet, I will be using a 6mm 2 flute endmill (this is so I can do everything I need without changing the tool), what would you suggest for the feed rate and plunge rate with a spindle speed of 2000 rpm (it will do 3250rpm max) Im looking for quality rather than speed but I dont really want to watch paint dry for any longer than needed so a compromise will be ok.



Rick

fragger6662000
11-09-2011, 02:02 PM
depends on what you are cutting and rigidity of the machine.

On my converted mill at 2000rpm in alloy i take 2mm DOC at 200mm/min

When i increase the sindle speed to 3000 i could take 3mm at 300mm/min

WD40 and GT85 make great cutting fuild for alloy

Jonathan
11-09-2011, 02:12 PM
Assuming a slot 2000rpm with 2mm DOC at 200mm/min sounds reasonable (as long as there is some cutting fluid/coolant around), however the tool deflection is borderline so it may not get a good finish. I would use that then at the end do a finishing pass taking say 0.2mm off all round at full depth.

Since the tool is 2 flute use half the feed for plunging (i.e. it's as if it only has one flute), so 100mm/min. Maybe a bit less, see how it goes.

WD40 does work well, but I doubt it does the machine ways much good. If you don't already have any it's well worth investing in the proper stuff.

P.S. Get some 6mm single flute carbide cutters - you won't regret it! I've just been cutting 3/4" thick aluminium with them on my router at 540mm/min, but only 1mm depth of cut. It may well do more but I'm not going to risk it without coolant.

EDIT: I'm assuming 'cut some bittlet' means aluminium! Also the above depends on other factors, such as if it's a deep slot...

Ricardoco
11-09-2011, 02:19 PM
depends on what you are cutting and rigidity of the machine.

On my converted mill at 2000rpm in alloy i take 2mm DOC at 200mm/min

When i increase the sindle speed to 3000 i could take 3mm at 300mm/min

WD40 and GT85 make great cutting fuild for alloy


Thanks Fragger The material is 6082 Aluminium Plate, the machine is very rigid piece of kit...

Ricardoco
11-09-2011, 02:30 PM
Assuming a slot 2000rpm with 2mm DOC at 200mm/min sounds reasonable (as long as there is some cutting fluid/coolant around), however the tool deflection is borderline so it may not get a good finish. I would use that then at the end do a finishing pass taking say 0.2mm off all round at full depth.

Since the tool is 2 flute use half the feed for plunging (i.e. it's as if it only has one flute), so 100mm/min. Maybe a bit less, see how it goes.

WD40 does work well, but I doubt it does the machine ways much good. If you don't already have any it's well worth investing in the proper stuff.

P.S. Get some 6mm single flute carbide cutters - you won't regret it! I've just been cutting 3/4" thick aluminium with them on my router at 540mm/min, but only 1mm depth of cut. It may well do more but I'm not going to risk it without coolant.

EDIT: I'm assuming 'cut some bittlet' means aluminium! Also the above depends on other factors, such as if it's a deep slot...

Hi Jonathan, you and fragger seem to be of similar opinions on this so i will take those settings as a theoretical maximum, and do a finishing pass as well, ( If you don't already have any it's well worth investing in the proper stuff.
):smile: I have.. Thanks for the input it really is much better than those calculators because they dont explain the 'Why' just the 'What'....:smile:

fragger6662000
11-09-2011, 02:46 PM
personally i would only use single flute for plastics and as to reduce heat and chip recutting, i would go for a three flute high helix cutter and go deeper and faster as you get more continuous chip engagement.

in production we use 2 flute at 25000rpm at 6mm DOC at 8m/min

Robin Hewitt
11-09-2011, 04:37 PM
Still, 75v / 80V is nothing compared to the 240V driver. I think Robin Hewitt used them on his mill?

Am I the only one brave enough? :heehee:

fragger6662000
08-10-2011, 11:51 PM
tool to tool in ten second and no skined knuckles.

whats the progress

just done this test.

http://youtu.be/lyJq8elbJnQ

i think it works well

Jonathan
08-10-2011, 11:55 PM
Hmm, that's nice but could be a problem long term as you wont notice if the thread or something starts seizing up. The impact driver will probably just keep going and potentially cause excessive wear / break something? Just a thought..
How long until automatic tool changing then?

fragger6662000
09-10-2011, 12:04 AM
i don't see it as going to be a problem as the drawbar is the soft expendable part. As the tapers and threads are hardened steel.

i2i
09-10-2011, 12:27 AM
tool to tool in ten second and no skined knuckles.

whats the progress

just done this test.

http://youtu.be/lyJq8elbJnQ

i think it works wellnow you need to mount it on the machine and have a foot switch.

m_c
09-10-2011, 12:29 AM
There are quite a few impact gun drawbar designs kicking around, and I've never seen anybody mention having any major problems with them.

Biggest issue with using an impact gun, is getting a consistent torque.

Also, don't rely on the threads in the taper shanks being hard enough not to be damaged by a soft drawbar. I bet if you tried filing them, they'll file down without that much effort.

John S
09-10-2011, 12:29 AM
Late into this post but converted 4 of these machines now based on the Warco WM16.
1605 ballscrews all round, 3.1Nm motors all round, direct drive on X and Y 2:1 belt reduction on Z
42 volts power supply and 542 drivers. If I had to do any more I'd increase the voltage to 70v and use the 80v 7 amp drivers de-rated to suit the motors.

cooliced
12-10-2011, 06:58 PM
Im very interested in this machines capability.

I currently run a CNC converted Sherline Mill and im now realising i need something bigger and better.

Keep us interested in this project please

Stu

cooliced
14-10-2011, 12:51 AM
John S / Ricardoco (http://www.mycncuk.com/forums/member.php/2597-Ricardoco)

Could you please link the controler you would use for this mill and a suitable place within the UK to purchase it.

Thanks

fragger6662000
15-10-2011, 10:27 PM
on my machine i used a G540 with 3 x 380oz and 1 x 940oz motors from kelinginc.

it was there 4 axis kit with power supply

cooliced
16-10-2011, 01:15 AM
Thank you very much, im probably gonna purchase this mill and that setup. (Sorry to hijack this thread) but.... does anybody have the dxf for the motor mounts?