[radioman]

hi guys... I'm new to this hobby and have built a cnc machine... gone through all the pain like everyone else to precisly build this thing just so i can make a really big one, using this ugly one to cut the parts. Using mdf and ground rod for the axis's and steppers for the drives it was all going very well indeed..... fired up the thing got the x and y sort of running spent loads of time on the z axis as well. did a test where by jogged out a foot or so and it came back to precisly the exact spot... i couldnt believe it... so i thought lets tune the motors, watched the tutorial and went to work... now the y axis judders... the x and z axis make bad sounds cant seem to get the thing to go any faster..... put all the settings back, tried to eliminate play in the y axis but when i want to make the machine go faster it aint happening... you guys have heard all this before right?

so you can help? please? please?

[eloid]

hi guys... I'm new to this hobby and have built a cnc machine... gone through all the pain like everyone else to precisly build this thing just so i can make a really big one, using this ugly one to cut the parts. Using mdf and ground rod for the axis's and steppers for the drives it was all going very well indeed..... fired up the thing got the x and y sort of running spent loads of time on the z axis as well. did a test where by jogged out a foot or so and it came back to precisly the exact spot... i couldnt believe it... so i thought lets tune the motors, watched the tutorial and went to work... now the y axis judders... the x and z axis make bad sounds cant seem to get the thing to go any faster..... put all the settings back, tried to eliminate play in the y axis but when i want to make the machine go faster it aint happening... you guys have heard all this before right?

so you can help? please? please?

back off your setting in the motor tungng page to half the value u got them set and retune them ...sounds like you motors have maxed out ....what size are they what size of machine?

[Stewey]

Which turorial on tuning the motors/PID is that, and where did you get it?

Thanks,
Ian

[radioman]

Thanks for your reply.

I will take some pictures tonight and upload them. this will give you some idea to the size. I have already reinstated the original settings for the motors but it is awfully slow... going to take ages to cut anything.

The turorial was on the artsoft USA website home of mach 3 in the tutorial section.

[radioman]

got some pics how do i show them. chris.

[ger21]

Click the go advanced button than manage attachments

[ger21]

Can you tell us the pitch of your screws, and what motors, drives, and voltage your using?

[radioman]

The threads are ..well i dunno but i can count 14 peaks per inch, the motors have the no. SY60STH86-3008BF on the lable they came from zapp ltd sold as nema 23... i have a stepsync controller (now no longer available i understand) it has chopper technology on it, and i have a power supply of 20v dc 10amp all running on mach3, by the way the nuts on the threads are crap i think they are just white nylon derlin... should i use ballnuts? cheers chris.

here are some pictures.

[awerby]

Is 20v all your Stepsync controller can handle? Are you running them in unipolar or bipolar mode? They should be able to deal with more voltage; 25 times nameplate (3.9v unipolar for your motors) gets you to 97.5v. Most controllers will handle 50v or so, but check the specs on yours, if they're still available.

Andrew Werby
www.computersculpture.com

The threads are ..well i dunno but i can count 14 peaks per inch, the motors have the no. SY60STH86-3008BF on the lable they came from zapp ltd sold as nema 23... i have a stepsync controller (now no longer available i understand) it has chopper technology on it, and i have a power supply of 20v dc 10amp all running on mach3, by the way the nuts on the threads are crap i think they are just white nylon derlin... should i use ballnuts? cheers chris.

here are some pictures.

[stevespo]

I can't quite tell from the picture, but it looks like your motors are just sitting on those threaded carriage bolts. How are they attached? Those motors should be attached to those standoffs with a nut, at least. Looking at the pictures, it seems like they're being held on by the motor coupling. I could just be seeing things...

Otherwise, it looks like a nice machine. I'm sure it will quite serviceable once you work out the bugs. We've all been there.

Steve

[hemsworthlad]

Radioman I Sent you a PM.

[radioman]

I can't quite tell from the picture, but it looks like your motors are just sitting on those threaded carriage bolts. How are they attached? Those motors should be attached to those standoffs with a nut, at least. Looking at the pictures, it seems like they're being held on by the motor coupling. I could just be seeing things...

Otherwise, it looks like a nice machine. I'm sure it will quite serviceable once you work out the bugs. We've all been there.

Steve

the motors are bolted very firmly to the mdf in such a way as to minimise any backlash.

there is still backlash so i suppose its virually impossible to build a machine out of mdf without it.

chris.

[radioman]

Is 20v all your Stepsync controller can handle? Are you running them in unipolar or bipolar mode? They should be able to deal with more voltage; 25 times nameplate (3.9v unipolar for your motors) gets you to 97.5v. Most controllers will handle 50v or so, but check the specs on yours, if they're still available.

Andrew Werby
www.computersculpture.com

I am running the motors in bipolar parrallel i hope this is the right thing to do.
i will try to up the voltage tommorrow and see what happens.

i seem to remember setting the fpd to 2.5 volts, I take it this is nothing to do with the supply voltage?

chris.

[stevespo]

Ah, I see - you've tapped the motor plate to accept the bolts. My mistake.

Steve

[radioman]

Ok guys upped the voltage to 30v (thats as far as i can go on this power supply) and the motors ran a lot better got the x axis up to 475mm per min the z axiz to the same but the y axis only up to 228mmper min which is still slow but better, so i now got to sort out he stiffness in the screws and maybe upgrade to ballscrews...but can you get them for any thread? also i think my driver card and power supply need to be udgraded as well... which is the best one for these motors. thanks chris.

[hemsworthlad]

Ok guys upped the voltage to 30v (thats as far as i can go on this power supply) and the motors ran a lot better got the x axis up to 475mm per min the z axiz to the same but the y axis only up to 228mmper min which is still slow but better, so i now got to sort out he stiffness in the screws and maybe upgrade to ballscrews...but can you get them for any thread? also i think my driver card and power supply need to be udgraded as well... which is the best one for these motors. thanks chris.

Hi Chris, the term ballscrews tends to be used as 1 item, but really you buy a ballnut and ballscrew(thread) and usually they are bought at the same time.
Although the screw in principal is not too differant to a normal thread it differs in that it's built to a lot lot higher precision and usually a larger pitch.

The Ballnut on the other hand is completely differant beast and full of balls and again precision built and matched to the screw.

On the drivers motor side, you are just outside the Gecko G540 range with these motors, this would have been your best option.
There's loads of differant alternative's, gecko's are popular stateside and considered one of the best, but in uk things are a bit more limited but still a bit of choice.
Zapp's PM752's will do every thing your looking to do with a bit of spare capacity left over.
The smaller PM556 will work but are just a bit down on the volts side limiting you to 50v and your motors work best at 57v, meaning you will never get full performance out them plus you'll be running the drivers at the edge all the time when working the machine hard, for a few quid more i'd get the extra hump.