Topics

1

General Mach Discussion / Is this backlash or missed steps????

« on: June 08, 2009, 07:51:19 AM »

I have had my router going for about a week now and have cut a couple of simple shapes with it. This morning I tried to cut out something a little more complex. Not a very good idea. I will describe what is happening first. Doing a simple move to check my steps works perfect, If i tell it to go 1" it goes 1.00". Great. Next cut out a square or circle again perfect ( or good enough for wood ). Then cut out something that is going to take a while, Not great. I wrote the macro that it describes in the config guide that follows:
F400
G20 G90
M98 P1234 L10
M30
O1234
G1 X20
G1 X0
M99

After the 10 moves the X axis will come up 0.011 short from zero, So I thought to double it. After 20 moves of 20" it comes up 0.022 short of zero and it doubles again after 40 moves. I have a moving gantry type (4'X8') with the 1200oz motors and the 72vDC supply from keling driven by 203Vs on both the x and Y axis. THe kernal speed is 35000. I have also tried the backlash function but that doesn't seem to work either. The same is happening with the Y axis also. The only difference is that is starts out as being 0.015 over with 10 moves of 20" and doubles with 20 moves then doubles again with 40. I have R&P on the X and Y axis with a set of timing pulleys to gear down. At first I was running @ 400 ipm then went down to 50, the same result in both cases.
I someone could help of have any ideas I would appreciate it.