Need Help!- Router Problems

[sodfarmer]

I'm having a problem with my router. I have ran test parts and this is what they come out looking like. The square is 4"x4" outer and 2"x2" inner. The inner corners are not the same. Corner to corner measurements are 5.582 & 5.617, the left side dimensions on the x axis looking @ the picture is 3.988 on the left, the right side is 3.986. Its running 100 IPM. I'm running Mach 3 and Sheetcam. I would appreciate any feedback. Its a stepper system, the x and y axis are spring loaded. Thanks

[ger21]

If the part is not square, there's a good chance the machine is not square. You may also have some flex in the machine? Try cutting at 50ipm and see if it's better.

[jsheerin]

It must be more than the machine being out of square - if that was the case the corner to corner measurements would be off but the opposite side lengths would be the same. I suppose it could be backlash, but I would go with Gerry and suspect flex somewhere first. Cutting at the lower speed should show if this is the case - if the error gets smaller it's probably due to flex.

Is this your machine: http://www.cnczone.com/forums/showthread.php?t=92063
When you say 'spring loaded', you mean the pinion is spring loaded against the rack, right? So that should get rid of backlash...

[sodfarmer]

Yes thats my machine and yse the pinion is spring loaded. Its changed since those pictures. I think I figured out my corner to corner square problem. I had to adjust one of my home switches on the x axis. After that I ran another test part and it came out dead on. I slowed down my feed rate and plunge rate to 50 ipm, the inside corners came out better. After the post last night I put a pen it the router, when I ran the program, the part was alot better. I will post updated pictures in the next few days. I think some of my problems are in the Z axis. Thanks for the help.

[sodfarmer]

I think I pretty much figured out my problems. I need to do some work on my Z axis. The plate my router is mounted to has some flex. This has been a interesting journey. Just when I thought I had everything figured out something else would come up. I guess thats to be expected. The X axis is made out of 4x6x1/4" tube and the Y axis is made out of 2-1/2 x 2-1/2 x 3/16 angle iron. If I did it again I would buy a different Z axis. Hind site is always 20/20. Thanks for the help.

[johnmac]

As DIY'ers, we don't get the luxury of prototyping and testing as the pros do. We need to get it right the first time.

John