Problem- Opposite of Backlash?

[MRM RCModels]

Yep, it's not a trick question.

I just completed my X3 cnc conversion and have been making quite a few parts. I've adjusted all of the axis's to 0 backalsh at 0.5in and 5in. I can repeat this 10 times without fail. My only problem is that all of my parts are 0.01"-0.008" over the perspective measurement in the X and Y axis. I'm pulling my hair out on this.

Anyone have an idea on how to fix this?

[Khalid]

just check ur tool dia again and also check for run out in tool holder....

[MRM RCModels]

Originally Posted by Khalid just check ur tool dia again and also check for run out in tool holder....

I checked for run out in the tool holder: less that 0.001 at full rpm. What did you mean by check to tool diameter? Do you mean in Mach 3?

[jalessi]

Have you checked for a burr in the tooling or dirt inside the collet?

[MRM RCModels]

Originally Posted by jalessi Have you checked for a burr in the tooling or dirt inside the collet?

Check for dirt? Now that's something I haven't done yet. Would that really make that much of a difference?

[Khalid]

Check the diameter of tool with Vernier calliper. If its right the other thing may be the STEP/UNIT to be corrected in Mach3 for both X and Y axis

[Khalid]

Draw a circle of about 50mm diameter and check whether the circle is round or not...Check the diameter readings on 0-6Oclock and 3- 9 Oclock.

[jalessi]

If you have small pieces of any type of debris in the collet or between the collet and tool or spindle it could cause additional runnout.

Since you have checked for runnout and you only have .001 then its not really bad however that could be .001 on all sides of what ever you are cutting.

[Khalid]

Draw a circle say 50mm diameter and check the 3-9 oclock and 0-6 oclock readings...

[Khalid]

Originally Posted by MRM RCModels I checked for run out in the tool holder: less that 0.001 at full rpm. What did you mean by check to tool diameter? Do you mean in Mach 3?

May be the case... if u gave the tool dia 3mm in ur CAM program and actually the tool u are using in ur machine is 3.2mm also with a little bit run outat the tip of ur tool.....u will be having the same trouble..

just my 12 x 70000/12 cents...

[tauntdesigns]

If you had to set your steps very far from 10160, I'd say something is loose and moving around some. Spanner nut pre-loading bearings? A block not fully tight?

When I got my kit, I put in 10160, and every move in the same direction checked dead on and when I changed direction there was .0007" backlash and every move in that direction was dead on.

After saying all of that,.......... Yea, I don't know either! sorry

Good luck,
Jack

P.S. If you had dirt or something in the collet, the endmill can get out-of-round. You can check that by putting an indicator on one of the flutes of the endmill and spin the spindle.

[Khalid]

Originally Posted by tauntdesigns P.S. If you had dirt or something in the collet, the endmill can get out-of-round. You can check that by putting an indicator on one of the flutes of the endmill and spin the spindle.

Just spin the spindle by hand