Loosing Position

[dannymil]

I am continually losing position in all 3 axis. will lose as much as .125" per pas per axis. Have done everything from upgrading to the new RBK box to getting a new/faster PC. Efficiency is 74.3. cutting hardwood at speed of 1 to max 1.5. Any advice? :confused:

[ron_moorehead]

Does it always loose position when you run the machine? Even with out cutting anything?

[bleeth]

Are you sure you are actually losing steps? Check your unit values. If they are off for the gears you have that would cause a regular deviance from expected distance.

[dannymil]

I read quite e few of the troubleshooting forum entries and gathered that I may have a grounding issue. I ran a ground wire from my breaker box to the table, the X carriage, and the Y carriage. Now the X and Z axis work perfectly but still losing position on the Y, although it is better than it was. Unit values are what they are supposed to be and yes, it does lose position slightly during air cutting. Checked all the Y wiring and plugs but am not seeing anything out of ordinary.

[bleeth]

Well it sounds like you have tracked the problem but you should also ground to your z. Also make sure that you don't set up a grounding "loop" which can create some issues. So ground line may run from z slide to y carriage to x gantry to frame and then on to your earth ground. Make sure you are good to bare metal for the grounding spots. If you have an ungrounded vacuum system some have had that interfere with accurate movement. For testing purposes I like to v engrave shallow lines in some scrap and check measurements that way rather than cutting parts. That way I know I am not creating an error through bit deflection or an out of plumb z. Checking the z can be done with a bent rod and a dial indicator or a block and careful line marking. If you use a large diameter surfacing bit you can see extreme ridges between passes as well if your z is not plumb.

For squaring I use the 3, 4, 5 system from intersecting lines in y and x direction. Getting it perfectly tweaked for accurate cab parts can take quite a bit since most of us who do use our machines for "standard" cabinets like our parts to come out dead square and accurate.