Motor speeds and tuning using Mach 3

[opiesbro]

So I have watched some of the videos on youtube and tried to do what they say as far as calibration. When I go to set the steps I first set the motor tuning to 30 on the velocity and 2 on the acceleration. When I calibrate the steps it traveled way past even though I had already set the steps at a lower speed. Then when I go in and change the velocity the steps are no longer good for the position. I have settled on 15Vel and 2 Acel as shown in the picture. I am using KL23H276-30-8B motors wired Bipolar (parrallel). The other thing I notice is the motors get very warm and hum a little more than I would like at idle. When I run a program it goes at slow speed even when F100.0 is used. My setup is a taig mill, G540 controller, and mach3 free version currently. My PC has the port set to EPP and I am using the LPT cable. If someone can give me some starting settings from a same setup or similar that would be great.

Thanks,

Al

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[Kenny Duval]

You are little bit lost in the settings.

1. The number of steps is the number needed to move the table a defined distance. This is dependent on the ballscreww pitch and any gearing in place if you aren't direct driving the screw. This number is not related to the other 2 numbers.

2. Velocity is how fast the machine will move when moving at 100% jog rate.

3. Accel is setting how much time it takes to get it moving from a dead stop.

In some thread around here there is the mathematical formula for figuring out your Steps/Per setting from which to start. I can't remember it.


Velocity and Accel you will need to figure out. Start low and keep ramping them up until you get a stall condition then back them down 20%.

[opiesbro]

You are little bit lost in the settings.

1. The number of steps is the number needed to move the table a defined distance. This is dependent on the ballscreww pitch and any gearing in place if you aren't direct driving the screw. This number is not related to the other 2 numbers.

2. Velocity is how fast the machine will move when moving at 100% jog rate.

3. Accel is setting how much time it takes to get it moving from a dead stop.

In some thread around here there is the mathematical formula for figuring out your Steps/Per setting from which to start. I can't remember it.


Velocity and Accel you will need to figure out. Start low and keep ramping them up until you get a stall condition then back them down 20%.

Kenny,

I understand the difference between steps and the speed settings. That's why I don't understand why the steps don't stay the same when the speeds are changed. Another thing I noticed that the position on my Mach readout changed without moving the servo. Also the first time I do the auto calibration after adjusting the speeds it makes the .010 move quickly and usually moves about .026". I type in the actual and accept the steps then run it again. This time it goes real slow and accurate within .001". I adjust the speeds again and the accuracy is gone again.

Thanks,

Al

[opiesbro]

Ok so here is some more after I tried to make the motor stall. It won't let me set the velocity over about 31. I tried to set it at 50 and it automatically set it back. Also I could never get the motors to stall.

Kenny,

I understand the difference between steps and the speed settings. That's why I don't understand why the steps don't stay the same when the speeds are changed. Another thing I noticed that the position on my Mach readout changed without moving the servo. Also the first time I do the auto calibration after adjusting the speeds it makes the .010 move quickly and usually moves about .026". I type in the actual and accept the steps then run it again. This time it goes real slow and accurate within .001". I adjust the speeds again and the accuracy is gone again.

Thanks,

Al

[Kenny Duval]

Steps per should always be the same once you have determined that number. . If the numbers are changing then you have play in the mechanics or stiction. Both will cause you to chase your tale a little.

[woffler]

Try doing this ,jog the motors and see how fast they go find a speed you are comfortable with somewhere in the middle .

If to fast adjust your settings down if not fast enough go up ,now that your comfortable with how fast it is going we will set the steps per inch.
Take a digital caliper or a dial indicator and use a small amount say .25 for your first move ,go to the settings page in mach 3 down at the bottom left corner set steps per inch.

Pick a axis say, x tell it to move .25 and then hit enter how far did it move ? enter that hit enter and the it will ask if that's ok say yes.

Now after you have done that, do it again with a bigger amount say 3 or 4 inches and keep doing it until you get it to do the same amount each time.

And keep a eye on your motor setting 's because mach will some times change them for you !! ,best to record them just in case they change you can just re enter them.
After you get them set then check for backlash ,go the same direction g1 f 35 x2.00 and then give the command g54 x0 and see if it comes back to 0 if not, you have what ever the difference is as backlash.

After you get all done take a tenth's indicator and do it all over again and get it as close as you can ,i use a 246 block ground to .0001 accuracy for this.

Or use what ever you can measure accurately, you can use a micrometer standard bar if that's all you can find, after all this mess you should be pretty close on .

Cut some parts and see how they come out ,i like to use a few dill holes a pocket and a couple of parallel lines with a profile and measure your stock before hand so you can compare the dimensions you programmed it to cut ,hope this help's have a nice day and be patient.

[opiesbro]

Well just as I was leaving my machine I decided to open Mach and try my program again. Before closing it I had it calibrated pretty close and ran the program. When I started Mach again I hit the go button and it was like when I started on it today. I am opening Mach with the loader and clicking on the same file. Does the XLM file never save and when opened through the loader it's back to how I downloaded it? Also I tore the apart the X and Y axis and made sure they were tight and moved free. I did notice that the motors are getting hot. They are not so warm you can't touch them but you can't lay your hands on them. I think this is why the feed rate is real slow when it is suppose to be in rapid.

Steps per should always be the same once you have determined that number. . If the numbers are changing then you have play in the mechanics or stiction. Both will cause you to chase your tale a little.

[woffler]

No your xml does not change it is what you put in it,any changes you make in mach you must hit enter and then close the program and restart to save the setting's or they will not be saved.

A stepper motor is always applying power,to it self to hold still when stopped and they are noisy as all get out .

You may have a bad or corrupted mach 3 file ,it has happened to me before ,if you are still having grief look in the mach 3 folder and save your xml file to the desktop and uninstall mach and reinstall it .

This will sometimes fix thing's up or abandon your old xml file and make a new profile and start over ,did you run the driver test when you installed mach?

And what kind of computer are you using with what operating system ,you should have nothing on that pc except mach 3 and a pdf reader .

[opiesbro]

I will try reinstalling Mach. My PC is a basic dell running xp with chrome, IE, standard programs installed from windows, Mach, VCarve pro 6.5, VCarve pro 7.0, adobe reader, and teamviewer. I also read that taig should be set to 16,000 steps per inch with a 200 step motor. Mine keep calibrating out to around 40,000.

Another thing I just noticed is when I open Mach I'm using the loader and opening the same profile. But when it loads up a different start screen from art soft comes up.

No your xml does not change it is what you put in it,any changes you make in mach you must hit enter and then close the program and restart to save the setting's or they will not be saved.

A stepper motor is always applying power,to it self to hold still when stopped and they are noisy as all get out .

You may have a bad or corrupted mach 3 file ,it has happened to me before ,if you are still having grief look in the mach 3 folder and save your xml file to the desktop and uninstall mach and reinstall it .

This will sometimes fix thing's up or abandon your old xml file and make a new profile and start over ,did you run the driver test when you installed mach?

And what kind of computer are you using with what operating system ,you should have nothing on that pc except mach 3 and a pdf reader .

[ger21]

A motor running on a G540 will have 200 x 10 = 2000 steps per revolution.
I believe that a Taig has a 20 tpi screw, so it's 20 x 2000 = 40,000 steps per inch.
I'd just leave at that until you get your accel and velocity settings correct, then adjust for precision. This number will NEVER change. If it does, then you're probably losing steps during the calibration process.

It won't let me set the velocity over about 31. I tried to set it at 50 and it automatically set it back

Your kernel speed will determine that maximum velocity setting you can use. At 25Khz, you can output 25000 steps per second. With your 40000 steps/inch, this equals a max of about 37 ipm. If you want higher speeds, you need to increase the kernel speed.

[opiesbro]

As far as missing steps how do I solve that? Is a smooth stepper the only way?

A motor running on a G540 will have 200 x 10 = 2000 steps per revolution.
I believe that a Taig has a 20 tpi screw, so it's 20 x 2000 = 40,000 steps per inch.
I'd just leave at that until you get your accel and velocity settings correct, then adjust for precision. This number will NEVER change. If it does, then you're probably losing steps during the calibration process.



Your kernel speed will determine that maximum velocity setting you can use. At 25Khz, you can output 25000 steps per second. With your 40000 steps/inch, this equals a max of about 37 ipm. If you want higher speeds, you need to increase the kernel speed.

[opiesbro]

So I think the kernel speed got me where I wanted to go for now. I was able to calibrate within .0002" and set the backlash. The motors seem to run cooler and everything calibrated out to at or about 40,000 steps. Backlash was at most .0025". I think as soon as I get a collet nut and a 1/8" collet I'm good to go. Next project is an A axis that is on its way.

As far as missing steps how do I solve that? Is a smooth stepper the only way?

[opiesbro]

I found a collet and ran my program. The image was a mirror image of what it was suppose to be. Then I started looking at it and found the polarities are backwards on my X and Y axis. Is this just as easy as changing the A and B wiring? I have the 8 wire kaling motors as stated below. I just don't know if I have to reverse the positive and negatives or if there is a setting in Mach to set? All three of my motors are wired the same and the Z axis is traveling in the proper direction.

Thanks,

Al

So I think the kernel speed got me where I wanted to go for now. I was able to calibrate within .0002" and set the backlash. The motors seem to run cooler and everything calibrated out to at or about 40,000 steps. Backlash was at most .0025". I think as soon as I get a collet nut and a 1/8" collet I'm good to go. Next project is an A axis that is on its way.

[Kenny Duval]

You should be able to flip the step direction pin from active high to active low I think. I'll try it on my machine and get back to you.

Confirmed. Change the "Dir LowActive" setting in Ports and Pins. No rewiring of the steppers required.

[opiesbro]

Kenny,

Thank you for pointing me in the right direction. Once I got home I opened the pin and ports and there it was. All is good now.

You should be able to flip the step direction pin from active high to active low I think. I'll try it on my machine and get back to you.

[Kenny Duval]

No problem man. The guys around here helped me a lot when I was trying furiously to figure this out.

[woffler]

Do not re wire the motor's !!!!!!!!! just change the direction in the mach three software under ports and pins, it is real easy ,and that is why you have one motor going one way and the other the other way..

Go to motor output's and change the DIRLOW ACTIVE from a X or a check mark what ever direction makes it go the right way for you ,if this is a mill then the (y axis) the table should come towards you for a + command say ( Y go 1.0 f 15 ) .

Then check the X axis it should go to the left as you face the mill table if you give it a + command (G0 x 1.0 f 15) , now i am sure you know that the Z goes Z- or down .

On your homing switch's for your Z axis it needs to home + to the top of the of the mill and your x and y axis will home in the negative - ,set this in homing and set your speed also that you want it to home .

[opiesbro]

So I got a 4th axis and started in on it. I calculated the steps and it is very close. It was running good in jog for a good amount of time today. Then I tried to move it in MDI and it moved really slow. So I turned the velocity up in motor tuning and now it either moves like a snail or is missing steps. I also noticed that my G540 is getting very warm to the touch. This is a 270oz motor that should be 3A so I left the 3K resistor in the plug. None of my other motors have that because they are over the 3.5A rating. After letting it cool down a little bit and trying again I get no change. Did my controller smoke that axis?

[woffler]

What command did you use in the MDI line ? If you want it to move fast use the g0 command it will be close to rapid speed .

Something like g0 A 360 and that should turn it one revolution at rapid speed ,and then you could use g01 f 25 A 90 and it should move at a slower speed and a quarter of revolution.

[opiesbro]

Thank you for the help. I found that I was looking at it wrong. I was thinking it should be similar to the other axis that were running on IPM. I ended up turning the velocity up to 20,000 and the acceleration to 15,000. Seems to have taken care of it.

Now I'm trying to figure out how to tighten up a 5C collet in this 4th axis?

Thanks,
Al

What command did you use in the MDI line ? If you want it to move fast use the g0 command it will be close to rapid speed .

Something like g0 A 360 and that should turn it one revolution at rapid speed ,and then you could use g01 f 25 A 90 and it should move at a slower speed and a quarter of revolution.