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kev20009
27-01-2017, 08:00 AM
Hi looking for some advice, build a DIY laser cutter, as you now there in no load on the x axis, so they swing fast,

Using 10mm belt 20tooth pulley nema 23 189nm wired parallel giving 4.2 amps, now I've seen some lasers running 500mm second and looks very fast, mine can 800mm second but does not look fast,

Now I can only set steps to 3200 any lower stalls and can only move at about 4mm second, so would changing the motor to smaller nema23 say 2amps 4 wire be better, or should I wire these in series, I used these as they where for a cnc but never used them so were spares,

Thanks for any help guys. Kev

paulus.v
28-01-2017, 12:39 AM
Why did you open a second thread with the same question?

If you want to get some feedback here, try to write/explain better and more detailed what you have.

What means 189nm? nm is the symbol for nanometre. You wanted to say Nm? Then I doubt there are 189...
What steps have you set to 3200? Are you talking about microstepping? Are you setting them in a drive unit? Has this drive unit a name/model number?
Your 800 mm/sec does not look fast... What software are you using? have you set the unit correctly? What is your acceleration?

You are asking about changing the motor but you did not tell us what drives you have (current and voltage ratings) and what is your supply voltage. Stepper torque at high rpm highly depends on the voltage and drive quality.

kev20009
28-01-2017, 08:11 AM
Why did you open a second thread with the same question?

If you want to get some feedback here, try to write/explain better and more detailed what you have.

What means 189nm? nm is the symbol for nanometre. You wanted to say Nm? Then I doubt there are 189...
What steps have you set to 3200? Are you talking about microstepping? Are you setting them in a drive unit? Has this drive unit a name/model number?
Your 800 mm/sec does not look fast... What software are you using? have you set the unit correctly? What is your acceleration?

You are asking about changing the motor but you did not tell us what drives you have (current and voltage ratings) and what is your supply voltage. Stepper torque at high rpm highly depends on the voltage and drive quality.

Thanks for reply, sorry about 2 threads was not sure if first was sent,

Motor 2amp series 4amp parallel 1.89Nm holding torque,
Driver. M542t. 24 to 50vdc 1.5amp to 4.5amp
Awc608 control with laser cad software
36 Volt switching power supply running drivers,
24 Volt switching power supply running Awc608
3200 is micro stepping

First this software as calibration like mach3, cut square 100mmx100mm till your steps are right,
Cuts ok 4mm ply as 10mms is needed, but engraving uses faster speeds, and I notice 20 minute job is about 50 minutes

Thanks again for reply kev

paulus.v
28-01-2017, 06:19 PM
What is the output power of your 36V PSU? How many motors and how long are they? Do you know their voltage and inductance?

I doubt that the steppers are the problem.
You have a 20 tooth pulley with 10 mm pitch? This means you are moving 200 mm with one motor rotation. At 800 mm/sec your motor has 240 RPM which isn't that high.

At high speeds acceleration is important. Unless you are cutting very large parts, you will hardly get to your max speed. Better the acceleration, quicker you'll finish the job with the same feedrate.

kev20009
28-01-2017, 07:54 PM
What is the output power of your 36V PSU? How many motors and how long are they? Do you know their voltage and inductance?

I doubt that the steppers are the problem.
You have a 20 tooth pulley with 10 mm pitch? This means you are moving 200 mm with one motor rotation. At 800 mm/sec your motor has 240 RPM which isn't that high.

At high speeds acceleration is important. Unless you are cutting very large parts, you will hardly get to your max speed. Better the acceleration, quicker you'll finish the job with the same feedrate.

thanks for replying again, thought I put belt size, 10mm wide t5 belt so 5mm pitch

psu 36 volt, 300w, 9.5 amps
3 motors, only 2 for x and y axis, 3rd runs table up and down, Size 76mmx56mm


General specifications motors

Step Angle 1.8 Rated Voltage (V) 2.6
Temperature Rise (℃) 80 Max (Max 2 phase on) Rated Current in Sereis (A) 2.0
Ambient Temperature -20~+50 Rated Current in Parallel (A) 4.0
Number of Phase 4 Resistance Per Phase in Series(+/- 10%) 2.2 (Ohm)
Insulation Resistance (MΩ) 100 Min (500VDC) Resistance Per Phase in parallel(+/- 10%) 0.55 (Ohm)
Insulation Class Class B Inductance Per Phase in Series (+/- 20% mH) 7.16
Max.radial force (N) 28 (20mm from the flange) Inductance Per Phase in parallel (+/- 20% mH) 1.79
Max.axial force (N) 10 Unipolar Holding Torque (N.cm) 1.4
Rotor inertia (gcm2) 480 Bipolar Holding Torque (N.cm) 1.89
Mass (Kg) 1.0

hope this helps a little thanks again kev

Robin Hewitt
28-01-2017, 09:09 PM
belt size, 10mm wide t5 belt so 5mm pitch

That's what I did, but it was wrong.
I bought T5 belt, tooth width 2.5mm
I bought T5 pulleys, tooth width 3mm
I stared at them in disbelief for 30 seconds then gave up an did something else. Couldn't believe it. What a rip.
If you have better luck let me know so I can resurrect it :beer:

Robin Hewitt
28-01-2017, 09:56 PM
From the HPC gears website...

Approx. belt flank play backlash are as follows:
T5 - 0.6mm
T10 - 1.1mm
AT5 - 0.2mm
AT10 - 0.4mm
AT20 - 0.8mm

Wonder if I could turn a 5.08mm pitch pulley down a tadge. The 5mm tooth seems a pretty good fit in that.
24t * .08mm / Pi = 0.61mm off the diameter. Might work. Or am I completely getting the sum wrong? :beer:

paulus.v
28-01-2017, 10:15 PM
You can go with the voltage higher and you will want to do that for better torque at high speeds.
According to the rated inductance you can go up to 32*sqrt(inductance)=43 volt.
Or if you take the rated voltage you have a max. of 20*2.6V=52 volt.

First calc. is more accurate but you have +/-20% inductance accuracy.
Personally I would try with 45-46 volt, but I don't know how would the drives tolerate that voltage. Maybe there are others here with more experience in these drives.
Have you tried wirh the drives set to the maximum amps rating? (SW1, SW2 and SW3 off)

It is possible to be able to improve your speeds in other ways as well. How easy are your axes sliding on their guides? The quality of the belts and pulleys, the weight of the gantry, reducing the inertia of the rotational loads, etc

paulus.v
28-01-2017, 10:48 PM
Wonder if I could turn a 5.08mm pitch pulley down a tadge. The 5mm tooth seems a pretty good fit in that.
24t * .08mm / Pi = 0.61mm off the diameter. Might work. Or am I completely getting the sum wrong? :beer:

It is not that simple to get the pulley tooth size. You have the pitch line, which corresponds to the belt insertion, where the belt bends. From there you calculate the gap between the teeth to correspond to the belt teeth dimension. The teeth on a smaller diameter pulley are narrower than those on a bigger diameter...

If you tension enough the belt you'll have no backlash even with a smooth belt. :friendly_wink: The teeth are there for timing ... at times :beer:

kev20009
29-01-2017, 04:33 AM
You can go with the voltage higher and you will want to do that for better torque at high speeds.
According to the rated torque you can go up to 32*sqrt(inductance)=43 volt.
Or if you take the rated voltage you have a max. of 20*2.6V=52 volt.

First calc. is more accurate but you have +/-20% inductance accuracy.
Personally I would try with 45-46 volt, but I don't know how would the drives tolerate that voltage. Maybe there are others here with more experience in these drives.
Have you tried wirh the drives set to the maximum amps rating? (SW1, SW2 and SW3 off)

It is possible to be able to improve your speeds in other ways as well. How easy are your axes sliding on their guides? The quality of the belts and pulleys, the weight of the gantry, reducing the inertia of the rotational loads, etc

Paul thanks for that advice, I got a 48 volt switching psu that can be turned down so will give it a go,

Axis all run on hirwin rails, will add photo today for you to see,
Thanks again you been big help. Kev

paulus.v
29-01-2017, 09:30 AM
The 48V PSU will make a difference. Try with 4.5A but check the motors temperature, if they'll get too warm or hot, reduce the current. Higher current increases only the low speed torque.

Hiwin rails need to be very carefully aligned to have a smooth movement.

https://www.youtube.com/watch?v=AGT5gXpcmBA#t=1m58s

kev20009
29-01-2017, 01:47 PM
hi paul photo of laser, still some bits to do, like airline laser pointer, and the cabinet is half done, kev

Robin Hewitt
29-01-2017, 03:05 PM
It is not that simple to get the pulley tooth size. You have the pitch line, which corresponds to the belt insertion, where the belt bends. From there you calculate the gap between the teeth to correspond to the belt teeth dimension.


But it looks like it might go, a small change in radius gives you 6 times as much off the circumference...

20523

kev20009
29-01-2017, 06:08 PM
But it looks like it might go, a small change in radius gives you 6 times as much off the circumference...

20523

got my belt and pulley from cnc4you they match perfect, kev

kev20009
29-01-2017, 06:14 PM
The 48V PSU will make a difference. Try with 4.5A but check the motors temperature, if they'll get too warm or hot, reduce the current. Higher current increases only the low speed torque.

Hiwin rails need to be very carefully aligned to have a smooth movement.

https://www.youtube.com/watch?v=AGT5gXpcmBA#t=1m58s

that video is good info, learnt a lot about hirwi rails, best way line 1 side and slide car to each bolt both sides as you tighten rail up, moves super smooth then, as there is drag on them before fitting as they are preloaded, kev

Robin Hewitt
29-01-2017, 08:58 PM
got my belt and pulley from cnc4you they match perfect, kev

Momentary hope, but they have nothing to fit my 15mm wide belt.

I think I might try 3D printing a pulley. Well, why not? :thumsup:

JAZZCNC
29-01-2017, 10:19 PM
The 48V PSU will make a difference. Try with 4.5A but check the motors temperature, if they'll get too warm or hot, reduce the current. Higher current increases only the low speed torque.

Yes it will make a difference it will blow the bloody drives up.!!! . . . . Why do you people give advise without looking and knowing exactly what your telling people to do.? These drives are 50V Max and 48vdc is far too close to limit and when traveling at high feeds the back EMF will fry the drives.

Kev stick with your current supply for now. I suspect your problem comes from lack of pulses due to high micro stepping with low pulse rate.
Setting lower micro stepping won't cause stalling and should allow higher tuning of velocity because less pulses are needed.
3200 is too high and pointless really because most steppers can't resolve higher than this. What it does help with is smoothness but this comes at the cost of high number of pulses which can lower your velocity if can't provide them. If using parallel port with 25Khz then this will most likely be your problem.

I've seen you mention 10mm but is that width or pitch.? T5 is 5mm pitch not 10mm. So with 20T your linear Pitch will be 100mm per rev.
Now given your using 3200 pulses per rev and using frequency of 25Khz which is standard frequency for parallel port the max RPM you'll get from your motors is 468.75Rpm.
This is calculated by taking frequency and dividing by pulses per rev or micro stepping in your case. This will then give Revs per Sec which you times by 60 to give RPM.
Now take the pitch and times by RPM to get max velocity. So 100 x 468.75 = 46,875mm/min or 781.25 mm/sec .

So you see if using 25khz with 3200 MS and 5mm pitch with 20T you can't possibly be reaching 800mm/sec.

Drop the Micro stepping to 1600Ms and your RPM doubles and so does your Max velocity. Lowering Ms won't or shouldn't cause stalling motors. Unless your trying to spin them too fast.?
By this I mean say if you used same parameters as above but with 400Ms then you could possibly tune the velocity so that the RPM is higher than the motors can handle so get saturated. Above 1500Rpm then steppers motors will struggle depending on load voltage etc.

magicniner
29-01-2017, 11:21 PM
Momentary hope, but they have nothing to fit my 15mm wide belt.

I think I might try 3D printing a pulley. Well, why not? :thumsup:

Is there a reason you bought pulleys and belts from different suppliers?

Robin Hewitt
29-01-2017, 11:25 PM
Is there a reason you bought pulleys and belts from different suppliers?

I don't think it matters where you buy them, the spec for the T5 pulley has 0.6mm of slop. I presume there is a good reason for this and it was not done simply to piss me off :hysterical:

paulus.v
30-01-2017, 12:33 AM
Yes it will make a difference it will blow the bloody drives up.!!! . . . . Why do you people give advise without looking and knowing exactly what your telling people to do.? These drives are 50V Max and 48vdc is far too close to limit and when traveling at high feeds the back EMF will fry the drives.
I only advised 45V :tongue: I said that I have no experience with these crappy drives. The Chinese say that the drives have over-voltage protection. I couldn't find any information about what chip is inside.

My THB6064AH based drives, rated at 50V max, were happy at 46V with my 150kg gantry. At 48V they tripped an error (from back-EMF) with no damage.

If they'll fry, he will be advised to get the AM882 and see how nice his machine will move at 100mtr/min. :devilish:

I was impressed by these DSP drives. They more than doubled the speed, with the same voltage and current setting.



If using parallel port with 25Khz then this will most likely be your problem.


He is using an AWC-608 Controller. I couldn't find any information about the step output frequency. Found somewhere "150MH". Could it be they spelled wrong 150kHz? :suspicion:



Now I can only set steps to 3200 any lower stalls and can only move at about 4mm second


What should I understand from the above sentence? What means 'lower' and 'only'?

I googled these drives and found them popular on 3D printers not a 50mtr/min laser...

kev20009
30-01-2017, 07:02 AM
Is there a reason you bought pulleys and belts from different suppliers?

They do 16mm wide belt and pulley, so these pulley suite your needs,

kev20009
30-01-2017, 07:11 AM
Yes it will make a difference it will blow the bloody drives up.!!! . . . . Why do you people give advise without looking and knowing exactly what your telling people to do.? These drives are 50V Max and 48vdc is far too close to limit and when traveling at high feeds the back EMF will fry the drives.

Kev stick with your current supply for now. I suspect your problem comes from lack of pulses due to high micro stepping with low pulse rate.
Setting lower micro stepping won't cause stalling and should allow higher tuning of velocity because less pulses are needed.
3200 is too high and pointless really because most steppers can't resolve higher than this. What it does help with is smoothness but this comes at the cost of high number of pulses which can lower your velocity if can't provide them. If using parallel port with 25Khz then this will most likely be your problem.

I've seen you mention 10mm but is that width or pitch.? T5 is 5mm pitch not 10mm. So with 20T your linear Pitch will be 100mm per rev.
Now given your using 3200 pulses per rev and using frequency of 25Khz which is standard frequency for parallel port the max RPM you'll get from your motors is 468.75Rpm.
This is calculated by taking frequency and dividing by pulses per rev or micro stepping in your case. This will then give Revs per Sec which you times by 60 to give RPM.
Now take the pitch and times by RPM to get max velocity. So 100 x 468.75 = 46,875mm/min or 781.25 mm/sec .

So you see if using 25khz with 3200 MS and 5mm pitch with 20T you can't possibly be reaching 800mm/sec.

Drop the Micro stepping to 1600Ms and your RPM doubles and so does your Max velocity. Lowering Ms won't or shouldn't cause stalling motors. Unless your trying to spin them too fast.?
By this I mean say if you used same parameters as above but with 400Ms then you could possibly tune the velocity so that the RPM is higher than the motors can handle so get saturated. Above 1500Rpm then steppers motors will struggle depending on load voltage etc.

Hi jazz, The belts are 10mm wide t5 20 tooth pulley,
This is a laser cutter running awc608 laser controler,

The steps it's set to now I can move back and forth nice, but if set them lower they just move 3mm and stall, so not sure if this is through psu needing bit more power, or turning amps up,

The 48volt psu I got as a ajust screw, if this is turned down to lower volt would it hurt the psu or are they ok,

Thanks jazz kev

Robin Hewitt
30-01-2017, 11:29 AM
They do 16mm wide belt and pulley, so these pulley suite your needs,

I tried to buy one but it did not go well. The shipping estimate didn't work. I soldiered on, didn't flinch when one pulley plus shipping came to £14.23, typed in all my details, took the PayPal option. A message came up, PayPal not available and they wanted me to start typing all over again. I just don't have the stamina I used to :emptiness:

JAZZCNC
30-01-2017, 09:32 PM
Hi jazz, The belts are 10mm wide t5 20 tooth pulley,
This is a laser cutter running awc608 laser controler,

The steps it's set to now I can move back and forth nice, but if set them lower they just move 3mm and stall, so not sure if this is through psu needing bit more power, or turning amps up,

The 48volt psu I got as a ajust screw, if this is turned down to lower volt would it hurt the psu or are they ok,

Thanks jazz kev

Ok I see on the controller front and while I can't find the Frequency this controller works at I'm sure it will be more than 25Khz so lack of pulses shouldn't be problem. Still However lowering the MS shouldn't cause stalling motors provided you set it up corrrectly in the controller which might be your issue if not doing this.

The motors you are using are relatively high Inductance so will require more voltage to spin fast but still with 100mm pitch they should easily reach 500rpm if wired Bi-polar parallel.
If series wired then this could be your issue because torque drops away quickly as RPM increases and with only 36V may struggle to spin much more than 500rpm.

Do the Motors have 4 wires or 8 wires.?

kev20009
30-01-2017, 10:08 PM
Ok I see on the controller front and while I can't find the Frequency this controller works at I'm sure it will be more than 25Khz so lack of pulses shouldn't be problem. Still However lowering the MS shouldn't cause stalling motors provided you set it up corrrectly in the controller which might be your issue if not doing this.

The motors you are using are relatively high Inductance so will require more voltage to spin fast but still with 100mm pitch they should easily reach 500rpm if wired Bi-polar parallel.
If series wired then this could be your issue because torque drops away quickly as RPM increases and with only 36V may struggle to spin much more than 500rpm.

Do the Motors have 4 wires or 8 wires.?

hi jazz 8 wires wired parallel, the only settings that can be set in controller is calibrate the distance moved, table size, homing switches
I cut square 100mmx100mm and put that in till it gets to right um pulse, which works out at x 15.621760 and y 15.575712

thanks jazz kev

kev20009
30-01-2017, 10:11 PM
I tried to buy one but it did not go well. The shipping estimate didn't work. I soldiered on, didn't flinch when one pulley plus shipping came to £14.23, typed in all my details, took the PayPal option. A message came up, PayPal not available and they wanted me to start typing all over again. I just don't have the stamina I used to :emptiness:

yes that's thing that gets me, order a bolt six pound something delivery, order a 3mtr rail same delivery, but got to say it arrives next morning, I pay with paypal but use gest checkout but you got to tick the box,

paulus.v
30-01-2017, 11:27 PM
The motors you are using are relatively high Inductance so will require more voltage to spin fast
Hi Dean,

It would not be advisable to get the am882 drives and a decent toroidal psu (I guess around 60v, you have more experience..)?

I see that he had invested a lot in his build but got stuck with some crap drives, and he only needs two of them.

edit:

the only settings that can be set in controller is calibrate the distance moved, table size, homing switches

Kev, I told you about the importance of setting up acceleration. Did you get the idea?

From your controller manual:

【Max Acc.】: Acceleration when axis making accelerated or decelerated movement. Too a big setting may lead
to motor losing steps or dither; too small setting may cause slow acceleration and then slow
processing speed for whole image. For axis with big resistance, such as Y axes corresponding
with beams, typical setting should be within in 800~3000mm/s2 ; For axis with small resistance,
such as X axes corresponding with carts, typical setting should be within in 10000~
20000mm/s2;

JAZZCNC
31-01-2017, 01:24 AM
Hi Dean,

It would not be advisable to get the am882 drives and a decent toroidal psu (I guess around 60v, you have more experience..)?

I see that he had invested a lot in his build but got stuck with some crap drives, and he only needs two of them.

With 100mm pitch then shouldn't need it. 500Rpm isn't diffcult to reach provided theres enough pulses.

Now what I'm not understanding is the numbers given.? 15.62 for 100mm of movement would suggest close to 205mm pitch with 3200 MS.
So to me there must be ratio going on somewhere.? . . . or the Belts are not T5.?

paulus.v
31-01-2017, 01:45 AM
edit: :beer:

kev20009
31-01-2017, 05:19 AM
Hi Dean,

It would not be advisable to get the am882 drives and a decent toroidal psu (I guess around 60v, you have more experience..)?

I see that he had invested a lot in his build but got stuck with some crap drives, and he only needs two of them.

edit:


Kev, I told you about the importance of setting up acceleration. Did you get the idea?

From your controller manual:

【Max Acc.】: Acceleration when axis making accelerated or decelerated movement. Too a big setting may lead
to motor losing steps or dither; too small setting may cause slow acceleration and then slow
processing speed for whole image. For axis with big resistance, such as Y axes corresponding
with beams, typical setting should be within in 800~3000mm/s2 ; For axis with small resistance,
such as X axes corresponding with carts, typical setting should be within in 10000~
20000mm/s2;

Yes all the settings in there are ok and as been altered to suit, all these do is if your cutting then it moves to the next cut, it accelerate to fast and lose steps, or to slow moving to next cut, the speed settings are when your in the layers, as fast for engrave slow for cut,