Slide lubricant, bad alignment or not enough torque ?

[Robinwales]

The Story
I've inherited an old German aluminium Haase machine from my late father.
It appears to be the smaller version of this machine if you Google "Haase Cut 2000 Professional CNC mill and engraving machine "
The original controller was not working so removed it and replaced it with TB6560, Arduino, 24v power supply and using the existing steppers.
Got it moving but the thing struggled with skipping steps and that was using a drag knife on vinyl.

Bigger is Better, right ?
Bought some new steppers 23HS9442, DM542A drivers and a 36v supply from Longs hoping that this would fix the skipping steps problem. Got it all rigged up with Arduino and the damn thing still skips.
It's like the linear rails don't slide easily enough. They don't appear to have any ball bearings so it's just like metal on metal tube with grub screws for adjustment. I've tried silicone spray to lubricate them before use and adjusted the grub screws but no joy.

Am I missing something obvious ?
Thanks
Rob

[Robinwales]

31005

[Robin Hewitt]

Silicon spray can cause galling at a metal to metal sliding contact. It is famous for destroying air guns. While you clean it out you can investigate the problem.

Can you feel excessive drag when you wind the slide screws by hand?

Are you blessed with an oscilloscope? You could check out the Arduino step pulse. Is it excessively up or down? A square wave is perfect.

You can get small amounts of slideway oil, no need to get the whole 5 litres.

[dazp1976]

[

Bigger is Better, right ?
Rob


Nope. Only with the right voltage.
However, if you can't get up to at least 1000mm/min with it then something is definately wrong.
What speed are you trying to run it at as a matter of interest?.

[Cube3]

Is that some sort of IGUS bearing (sleeve) I see? It may be a replacement wear part or you my be able to find a IGUS bearing to fit.

Moving the slide without the ball screws should tell you quite a bit.

Gut feeling, with those steppers it's not the slides!

Sent from my SM-A715F using Tapatalk

[dazp1976]

Silicon spray can cause galling at a metal to metal sliding contact. It is famous for destroying air guns.
You can get small amounts of slideway oil, no need to get the whole 5 litres.

GT85 Teflon spray all day long for cleaning metal to metal surface slides.
I used to run automated equipment from Heidelberg machinery and they weren't wrong on that one.

Silicon spray! ..... Noooooo!!.

[dazp1976]

Is that some sort of IGUS bearing (sleeve) I see? It may be a replacement wear part or you my be able to find a IGUS bearing to fit.
Moving the slide without the ball screws should tell you quite a bit.
Gut feeling, with those steppers it's not the slides!
Sent from my SM-A715F using Tapatalk

With the inductance on those steppers, they need DM860 drives and minimum 60v to get decent high rapid speeds.
Proven.
But, never any issue on 36v running at 300rpm with 5mm pitch ballscrews, and my gibs were tight as (mill).

[Robinwales]

Silicon spray can cause galling at a metal to metal sliding contact. It is famous for destroying air guns. While you clean it out you can investigate the problem.

Can you feel excessive drag when you wind the slide screws by hand?

Are you blessed with an oscilloscope? You could check out the Arduino step pulse. Is it excessively up or down? A square wave is perfect.

You can get small amounts of slideway oil, no need to get the whole 5 litres.

Unfortunately, don't have an oscilloscope.
When turned by hand not sure I recognise any excessive drag, although I have nothing to compare it with. I've disconnected the threaded rod and tried sliding the carriages by hand and there is some metal to metal suction to get them moving. It's not possible to push them with your fingers and for them to slide from one end to the other, if you know what I mean.
Will try some slideway oil.
Thanks

[Robinwales]

Nope. Only with the right voltage.
However, if you can't get up to at least 1000mm/min with it then something is definately wrong.
What speed are you trying to run it at as a matter of interest?.

I would be happy with 1000mm
Would like to carve some beech and cut some birch plywood
Not really bothered by the speed, would just like it to be automated
Thanks

[Robinwales]

GT85 Teflon spray all day long for cleaning metal to metal surface slides.
I used to run automated equipment from Heidelberg machinery and they weren't wrong on that one.

Silicon spray! ..... Noooooo!!.

Aldi seem to do this spray will give it a try
Thanks

[Robinwales]

With the inductance on those steppers, they need DM860 drives and minimum 60v to get decent high rapid speeds.
Proven.
But, never any issue on 36v running at 300rpm with 5mm pitch ballscrews, and my gibs were tight as (mill).

As mentioned, not really a speed freak just want to overcome the issues at the moment.
I would be happy with any speed that doesn't stick.
Thanks

[Robinwales]

31007

[Robinwales]

31008

[JAZZCNC]

Ok, forget the nonsense about silicone spray, teflon or Lube oil for now because with those steppers running on 36V using lead screws then if it had been parked in the desert for six months and was bone dry they would still move that machine around at more than 1000mm/min if setup correctly.

So let me ask the questions which should have been asked by the others.?
#1 What micro-steps do you have the drives set at.
#2 What pitch are the lead screws (those are lead not ballscrews)
#3 What do you have for Steps per unit in the control software.

It doesn't matter how large your motors are if the controller isn't set up correctly and sending out the wrong number of pulses at the wrong time you will get stalling motors, hence Robin's oscilloscope question.
In the controller, you will have set the number of steps per unit, ie mm and this number is a calculation based on the micro-step setting on the drives, the motor step angle and the pitch of the lead screw along with a ratio if one is used.

So let's say your Micro-steps are set at 400 and the lead screw pitch is 5mm and it's directly coupled to the screws with no ratio. The motors will be standard 200 steps per rev
The calculation for Steps per mm would be 400/5= 80

If your controller doesn't put out the correct number of pulses then the machine will move the wrong distance and if it's very wrong with too many pulses then it would cause the motors to stall even if they had 10 x the power of what's fitted now.

I don't use Arduino's or GRBL etc so can't help on this but it doesn't matter which controller you use if it's not set up correctly regards the pulses it puts out then things like this will happen regardless of motor size or voltage.

[Robin Hewitt]

More might be better but I have just been playing with some dinky 5 phase steppers. They start out with a 0.8Nm pull out torque, sounds a bit limp, but they still have 0.25Nm at 3000rpm. 4 Amps 24 Volts. It's a different ball park :cocksure:

[Muzzer]

Also check the maximum step frequency and / or the minimum pulse width (similar thing). If you have it set too high frequency / too short pulse width, some of them may not get through to the driver. Try running at lower max frequency to see if this is an issue. I don't use steppers any more but last time I did, this was the issue causing me stalling / lost steps. Those settings would be in your controller, not the driver.

[Robinwales]

Ok, forget the nonsense about silicone spray, teflon or Lube oil for now because with those steppers running on 36V using lead screws then if it had been parked in the desert for six months and was bone dry they would still move that machine around at more than 1000mm/min if setup correctly.

So let me ask the questions which should have been asked by the others.?
#1 What micro-steps do you have the drives set at.
#2 What pitch are the lead screws (those are lead not ballscrews)
#3 What do you have for Steps per unit in the control software.

It doesn't matter how large your motors are if the controller isn't set up correctly and sending out the wrong number of pulses at the wrong time you will get stalling motors, hence Robin's oscilloscope question.
In the controller, you will have set the number of steps per unit, ie mm and this number is a calculation based on the micro-step setting on the drives, the motor step angle and the pitch of the lead screw along with a ratio if one is used.

So let's say your Micro-steps are set at 400 and the lead screw pitch is 5mm and it's directly coupled to the screws with no ratio. The motors will be standard 200 steps per rev
The calculation for Steps per mm would be 400/5= 80

If your controller doesn't put out the correct number of pulses then the machine will move the wrong distance and if it's very wrong with too many pulses then it would cause the motors to stall even if they had 10 x the power of what's fitted now.

I don't use Arduino's or GRBL etc so can't help on this but it doesn't matter which controller you use if it's not set up correctly regards the pulses it puts out then things like this will happen regardless of motor size or voltage.

1. Currently at 400
2. 3mm Pitch
3. 133.33

Tried with UGCODE Sender and Estlcam
Thanks Jazz

[Robinwales]

More might be better but I have just been playing with some dinky 5 phase steppers. They start out with a 0.8Nm pull out torque, sounds a bit limp, but they still have 0.25Nm at 3000rpm. 4 Amps 24 Volts. It's a different ball park :cocksure:

Thanks Robin that answer just went straight over my beginner's head lol

[Robinwales]

Also check the maximum step frequency and / or the minimum pulse width (similar thing). If you have it set too high frequency / too short pulse width, some of them may not get through to the driver. Try running at lower max frequency to see if this is an issue. I don't use steppers any more but last time I did, this was the issue causing me stalling / lost steps. Those settings would be in your controller, not the driver.

Please can you explain frequency ?
Thanks for the reply

[Muzzer]

Dunno what software you are using to drive the stepper drives but in the systems I use (LinuxCNC and Centroid), you can select the maximum pulse repetition rate for the steps. If you try to drive the stepper drives with too high a frequency, the input circuitry (usually optocouplers) can't process them consistently. IIRC, I've seen options for 100kHz and 200kHz, possibly higher (I don't recall right now).

The default for Centroid seems to be 200,000 steps per second (200kHz) and I know from experience that the Chinesium stepper driver I tried didn't work consistently with that until I reduced it to one of the lower settings. Have a look and see if you can see an option to reduce that in your system.

This is different to max velocity, as you may find the required step frequency to achieve max velocity is above what the driver can process, depending on your number of steps per rev, ballscrew pitch etc.

[Robinwales]

Sorted the problem and I'm ashamed to say it was a "One-Delta-Ten-Tango" error (1D10T)
I thought up was "on" with the dip switches, however up was "off" so I was only feeding the steppers 1 amp at the most.
Thanks everyone for taking the time to help.
(Slinks away to garage to be alone)