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Author Topic: Mach 3 Stepper motor Settings, Little help needed please!!  (Read 22669 times)

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Mach 3 Stepper motor Settings, Little help needed please!!
« on: September 30, 2008, 08:12:24 AM »
Hello all,

I have just finished all the wiring of the electronics for converting my Sieg X2 to cnc, still waiting to order cnc fusion kit so just mounted my motors to the bench for a test run with a slapped together bit of G code.
First thing that got me was the noise from the motors when idle, a hissing sort of loud air leak noise? Is this normal? Also they do get quite warm, how warm is safe? ???

Im just looking for someone to help me out or give any advice on what sort of settings i should have in the Mach 3 motor tuning page as in Steps/rev, Velocity, Acceleration and Step puls as i have read so many things telling me completly different settings!

I am using Motion Controls cnc kit #1 Which consists of:

1 x breakout board (very simple with port connection for pc and terminals for drivers/home switchs)

3 x 4.2A MSD542 microstepping drivers (default settings reccomended by MC- 8 microstep, 1600 steps per rev, full pulse, set by dip switchs)

3 x 3nm steppermotors FL60STH86-3008BF (1.8 Deg) 425 oz-in all wired bipolar parallel

2 x 40V, 7A non regulated power supply


I have played with various settings from default to many reccomendations from people on cnczone forum but still not happy that i have the correct settings that i need so thought i would see if anyone on here has any new ideas for a good starting point.

I do appreciate that i will not know the exact settings until i have the mill built and all bolted together but i would be alot more confident if i knew that Mach 3 was set halfway handy before i start wizzing beds around!

Any advice would or pointers would be greatly appreciated

P.s. A short Youtube vid of test run with all default settings on drivers and in Mach 3, Note you dont get to hear the high pichted hiss of motors that i did!



Re: Mach 3 Stepper motor Settings, Little help needed please!!
« Reply #1 on: September 30, 2008, 10:50:49 AM »

    It's really impossible for anyone to tell you what the correct settings for your machine will be - every machine is different.  Just start with a low acceleration - like 0.5, and crank the max speed up until the motors start stalling at the top end.  Back off perhaps 10% from where they stall.  Then start moving acceleration up, until it stalls on acceleration, and back off on the final acceleration setting.  Then, run the machine hard and make sure it really works reliably under more "dynamic" conditions.

Ray L.
Ray L.
Re: Mach 3 Stepper motor Settings, Little help needed please!!
« Reply #2 on: September 30, 2008, 12:17:48 PM »
Hello Darryll,
Here is a clip from the Gecko FAQ site.

Offline jimpinder

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Re: Mach 3 Stepper motor Settings, Little help needed please!!
« Reply #3 on: October 01, 2008, 02:13:04 AM »
The workbench is as good a place as any to get the bugs ironed out.
The first thing to do is make sure your drivers do not deliver more current than your motors can take. Check to find out the ratings for your motors, and then see if your driver cards can be limited to a fraction under the rating.

The voltage does not matter (and 40 volts is not excessive). My Geckos can be limited - 7 amps max, I have mine limited to 4 amps to drive my motors ( 2.5amps per coil - wired in parrallel). My third driver is a Routout CNC driver (from UK) which I had originally. This is a 2.5 amp driver on the Z axis and I have also noticed, when idle, that it hisses. I put it down to being slightly faulty (although it works well enough) but it may be that it is working up near it's maximum and this is the current limiting noise.

As far as speed is concerned ( and I take it you mean velocity in Config/Motor Tuning) then you can set this up fairly accurately if you know your gearing, and leadscrew pitch - you must have some idea.

Set the steps per inch first, and I am not going into that scenario again, there are enough posts on here. Your default driver card setting is standard - 200 pulses for the motor, and a microstepping setting of 8 = 1,600 per rev. If you are connecting the motors direct to your leadscrew then multiply by the number of turns the leadscrew requires to move the table 1 inch, and you are done. Mine is 10 so my answer would be 16,000 steps per inch. (I also have a 3 to 1 reduction so my real anwer is 48,000, but reduction depends on whether you are looking for speed or accuracy)

Once you have set you steps per, then you can set up the speed, and you must have a target that you want to reach. Yes, without load the motors should get there well enough, but it is nice to see them working at the correct speed, and it may be that there is some other reason that they don't - so try it. Acceleration is the other setting and leave this at 1 for the moment.

If the motors work well at your required speed, then increase it gradually until you get to the point when they start stalling. This is your maximum (well a little below that) - and you can increase the acceleration as well in a similar way.

At least when you put the motors on you will have something to aim at.

To listen to the music,  do a g2 or g3 over a 4 inch radius and it is facinating to watch the motors accelerate and decelerate in turn.

As has been said, motors get hot under load, and remember, unlike ordinary motors, they still have current going through them even when idle. Some driver cards reduce this to stop the motors getting too hot, which is why I said check your current output. As has been said 85 degrees is acceptable, and that is too hot to touch, so if you can put your hand on and keep it there you are OK.

Not me driving the engine - I'm better looking.
Re: Mach 3 Stepper motor Settings, Little help needed please!!
« Reply #4 on: October 01, 2008, 09:32:53 AM »
Thanks for all the replys,

I know it is a hard guess to know what settings i will need as i do only have the motors bolted to the bench but like i siad i just would like to know im heading in the right direction with the settings i already have.
Think it might be a bit easyer to know what i need and how hard i can push things once everything is bolted together as right now im unsure of the pitch of the ballscrews aswell.

The first thing i am going to check is the current the drivers are putting out as i know they are left at default for this kit which i think is 4.2A so might be a little to much. I will knock them down a notch and see if this make the motors make a little less noise, i know they do make noise but surly not as much as they are at present! Plus they do get rather hot with very little work, i can hold my hand on ther for about 10 seconds before its to much so they are running warm.

Jimpinder- The test G code that i put together makes each axis move one at a time in + & - direction then does a diagnal move of all axis followed by simulating drilling topped off with a 20mm rad going cw then ccw, the machining of the rad does sound crazy!! :) It just makes me want to get the thing all together and cutting some metal! Have to wait until next pay ceck before getting the mechanical side of things sorted though!

Thanks again for all the help