We have a tiag mini mill with a gecko g540 controler and mach3 software, we finally got it working and have solved several problems and finally tried to do some engraving today. we are cutting some letters in wood and noticed that the depth of the letters is not consistant, we lose several thousandths every time it goes to the next letter, about .007" per time. the x & y axis do not seem to have this problem. the dro reads the proper depth, but the motor does not repeat. any suggestions? we will be using this to engrave lettering on guns and the letters will be small and only about .005" deep, so it needs to be fairly accurate.

I use a Taig - but with steppers not servos.  Have been able to engrave to depths of .003 consistently - even when using the 4th axis for engraving rings.  No experience with steppers so can't offer anything about them.

Bob@BobsShop

Project Guns,
I built my own engraving machine. Accuracy of the z axis was very, very important to me.
When using a small radiused cutter, it dosen't take much to screw up an engraving, so repeatability,
absolute min backlash, etc needs to be delt with. 
The thing about CNC engraving a firearm is you only get one shot at it. When manualy done a mistake can
sometimes be covered up by the engraver.

"Fix  or modify" the machine to bring it to the resolution and accuracy you want. No shortcuts.

It only takes .002" with a .020 dia ball cutter to turn a fine line into a road marker. Should you actualy use a point
, you'll bust off the point of the tool in a heart beat if it goes in that silly little extra thou.

Attached is a pic of a small target with some small lettering which was cut into the back silver plating of a mirror.
60,000 rpm / .004 flat tipped carbide point tool, the letter width is .005" ( about .025 high ) as shown by the microscope pic.
The camera shot didn't come out to well with reflections onn the lettering. Just making my point about accuracy of the machine
compared to what you may want to engrave.
RICH

Try slowing the Z axis down in motor tuning, it could be that you are loosing steps on the rapid moves, increase the acceleration time so the motor has more time to get up to speed.

Graham

Try slowing the Z axis down in motor tuning, it could be that you are loosing steps on the rapid moves, increase the acceleration time so the motor has more time to get up to speed.

Graham

Thanks for the help, I slowed down the axis and increased the pulse width and that seems to have solved the problem.

I'll take Old English scrolling with a nice pheasant hunting scene on the shotgun rerciever.
Happy you got it working.
RICH

I'll take Old English scrolling with a nice pheasant hunting scene on the shotgun rerciever.
Happy you got it working.
RICH

Sorry, we don't do shot guns, here is what we do:

http://projectguns.com/rpdvideo2.html