Can someone explain "Full step", "Half step", "Quater step", etc. ???

[danmst3k]

Hi all, I'm about 90% done with my DIY CNC mill and I still have a few nagging questions. I'm running my stepper motors at "quarter step" and I have 5/16 threaded rod lead screws with one start, in mach3 I set the motor settings to 3600 for the number of steps per inch (200 steps x 18 thrds per inch). I'm not cutting yet but I did clamp a sharpie to the spindle mount and drew out the roadrunner sample file that comes with Mach3. It's a lot smaller then the wireframe shows. Is this due to the fact that I'm running at quarter step instead of full step? If I set my motors to full step would the drawn image be the right scale? Also, If I leave it on quarter step do I then change the motor setting to 14400 (3600x4)?

Dan D

[EvanZ]

Set it up to "draw" a 1 inch square then measure it. that will answer that question at least.

Evan

[Garfield2]

You want to run in 1/4 step (or smaller) mode to get the best from your motors. You need to adjust the step sizes in Mach to accommodate the difference in step sizes.

So for example lets say 10 steps in full step mode equal 10mm.

In half step mode you will need Mach to output 20 steps for the same 10mm.

In quarter step mode you will need Mach to output 40 steps for the same 10mm.

The motor tuning wizard allows you to adjust these values fairly easily for each axis (you might have different motor or screws on different axises).

Hope that helps,
Alan.

[ger21]

Originally Posted by danmst3k Also, If I leave it on quarter step do I then change the motor setting to 14400 (3600x4)? Dan D

Yes, leave it on 1/4 step and set the steps/unit to 14400.

[danmst3k]

Hey guys thanks for the feedback and suggestions. I did some more research and tried some things on my mill last night. I re-watched the tutorials on the Mach3/Artsoft website and they made more sense to me this time (I haven't watched them in a while). I tried the step wizard and that got me in the ballpark. I set the steps per inch to 14400 and then ran the wizard. I typed in 1 inch for the amount of travel but the machine only moved about approx .7 of an inch so I typed in .7 and the wizard set the steps to 15878. I thought this sounded really high so I tried moving the x axis 1 inch and it was really pretty close. I played with the number some more and got it spot on. Thanks again!

Dan D