Steps per motor rev.

[beebee]

Thanks.

[Richards]

You should be about there. If you enter 2,500 into Steps/Revolution for the X axis and 1.125 in the Overall Turn Ratio for the X axis and then use the MDI to give a G-code command to move to your pre-set home position (G0 X0), the X axis should be at its 0 position. Then if you give a move command to move the axis one inch, it should move one inch (G1 F20 X1.0). You may have to tweak the 1.125 number slightly to get exactly 1.0" inch, but you should have accurate control of that axis. Do the same thing for the Z axis substituting 3,000 for Steps/Revolution and 0.375 for Overall Turn Ratio for that axis.

[frijoli]

You asked how far the axis moves per revolution. Those two numbers are the result.
x =1.125. One turn
z=.375 One turn

One rotation of the servo motor shaft moves 1.125 " or the final drive?
How far per motor shaft rotation?

[swissi]

beebee,

there's a very simple way to check if the steps/rev are set correctly. Do the following:

• In the Axis Configuration page just set the "Overall Turns Ratio" to 1 for all axis and save the configuration.

• Make a marker on the motor shaft coupler on each motor

• Go into the MDI of CNC12 and enter the command G91 X1 F10 (this should take 6 seconds to complete a full 360 degree rotation)

• The motor of the X-Axis should rotate exactly 360 degrees. If it doesn't, your steps/rev setting is wrong and you need to adjust it until the motor axis turns exactly 1 time (360 degrees)

• Do the same for the Y and Z axis motor

• If you get exactly 1 turn, you can go back and set the revs/inch to 4 if the pitch of your lead screws is 0.25"/rev

• Go back into the MDI, install a dial indicator along the X-Axis and set it to 0. Command a G91 X1 F10 and your dial indicator should show exactly 1"

• If the dial indicator shows a little more or less, you need to adjust the rev/inch parameter up or down until you get exactly 1 inch

-swissi

UPDATE:
Added the feed rate to the command as Tom suggested (in case somebody else will come across this thread). With F10, one 360 degree rotation should now take 6 seconds to complete. Also fixed the typo I had (steps/rev instead of revs/inch).

[beebee]

This method looks promising. It’s a bit tricky doing the Y. Cant click the mouse and get
to the Y in time to see the movement. Tried doing a video but the axis moves too fast.
One time the lines were aligned. Looking at the video though I think it made multiple revolutions.

[tblough]

G91 G1 G93 Y1 F1.0 and the move will take 1 minute to complete. Should be enough time? Time to complete is 1/F, i.e. F2.0 = 30 seconds

[beebee]

Thanks tblough
I alway used CAM. As a result I’m not knowledgeable regarding general g code.
You input will make the process much easier.

[beebee]

I’m moving in the right direction. The Y axis is set at 1000 with one turn. And the X is set at 2500 with one turn. Just got the Z doing one turn.

Note. So as a test I did a 1 inch move on the X axis. But the axis moved almost two inches. I expected it to be much closer after the turns were in the ball park.

[martyscncgarage]

Pictures/video would help....

[beebee]

I’ll try to get a picture of the limit. The machine is near two walls. It’s very difficult to get a video. I added a picture of the Y axis limit.
https://drive.google.com/drive/folders/ ... an8vtCD3yj