mach3 setup issue with calibration

[PJRU0304]

Trying to setup and calibrate a new build. The CNC is a DIY 1200 x 800mm 3 axis router with a slave axis for the Y axis. I am using RM 1605 ball screws and SBR20 (16mm) linear rails NEMA34 motors an all axis DM860a micro stepper drivers. Running Windows 7. The problem I think might be in the driver settings, after doing the math for the calculation it looks like the velocity needs to be something like 5000, I think I came up with 5032 to make the motors run smooth in "motor tuning" the if I try an set up and calibrate the axis when mach3 asks how far would I like to move it, I put 10mm in and it moves the spindle 50mm. Then mach3 asks how far did it move and when I put in 50mm mach3 pop-up box tells me it will change the settings in motor tuning (velocity) down to 450 or so. At this point the axis hardly moves... sounds real week and troubled. I have looked all over and don't seem to see this issue anywhere, so my guess is I've screwed something up somewhere, but where. I think it might be the driver settings but after testing several settings on the drivers the problem comes out the same in the end. It seems like mach3 wants to go about 2mm per hour, not going to make many chips like that.thanksPat

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[jo_ky]

The steps per unit setting is in the lower left corner of the 'motor tuning' configuration dialog. What happens when you change that?

Steps per unit can be calculated from the screw pitch and motor steps per rev. You've already found a good velocity setting, I guess. I'm not surprised the "wizard" isn't helpful - just don't use it!

[ger21]

Yeah, you should be changing the steps/unit, not velocity.

[PJRU0304]

I am sorry it is the steps per that is changing not the velocity when I do the test, it changes down from 5032 to 450 or something like that I will try it again today Thanks for your input

[ger21]

The steps/unit has nothing to do with speed. It's what sets your accuracy.
You need to adjust your velocity and acceleration for your speeds. The commanded feedrate will determine the actual speed.
What microstep setting are the drives set at? It looks like maybe 1/10, or 2000 steps/rev?

[PJRU0304]

yes it is set to 2000, I tried it at 5000 and 10000 but it was not working the right way so I went back to the 2000 steps per and I can keep it constant there. I think the next thing to try will be the screw mapping setting's they just look a bit confusing. Right now if I try the test or just jog around the table and lets say I move 200mm, the DRO shows a much different number, much less like 12 or so? So that's what makes me think its the screw mapping. I keep wondering if I made a mistake when I bought the 1500mm ball screws (1605), maybe I needed to get a larger size like 20mm diameter, is it possible that is the problem here?You have been very helpful along this path so thank you for that and if you have any other suggestions please feel free to advise.Pat

[ger21]

It sounds like your motors are stalling, and losing position.

Do NOT even attempt to mess with the screw mapping. It has nothing to do with your problem, and you likely don't have the equipment to measure and set it up. Screw mapping is probably used by 0.0001% of Mach3 users.

Your steps/unit should be 400. Set it to that, and start testing. Zero the axis, move it across the table, then back to zero. The DRO should still read 0, and the axis should be where it started. If the position does not match the DRO, you are losing steps.

[PJRU0304]

alright I will give that a try, I set it to 1000 today and tested everything and it looked okay, but very slow. Maybe that is all I can get from it but I am going to try the setting you suggested and see what happens. It's been this long so a few more tries can't hurt. I did not mess around with the screw mapping for 2 reasons, 1 because you advised against it and 2 it just looks dark in there, I figured I would mess things up if I tried anyway.Thanks againPat