Topics

1

General Mach Discussion / Question about referencing

« on: January 11, 2006, 12:51:43 AM »

I've had a problem with referencing the X-axis that I can’t solve. Z and Y reference normally but when it gets to X, it will move anywhere from a ¼ inch to 1 ½ in and stop. No reference LED lit on the Diagnostic screen and no error message. The DRO shows the distance it has moved. It doesn’t matter if the reference (home position is 2 inches or 20 inches away, it moves it’s short distance and stops. Once it is close enough to the home switch (within the 1/4 to 1 ½ inch range) it homes normally. The homing speed is set at 50%. The only workaround I have is to jog the X-axis after it references the Z and Y until the X is close to the home position, then reference it again.

There got to be something simple I’m overlooking, but I can’t find it

Louis
 

2

General Mach Discussion / Bewildered and at wits end

« on: December 05, 2005, 10:54:48 PM »

I’m new to cnc, but have got far enough to know that I have a problem that is beyond my knowledge, or of knowing where to look.

Using Mach3 on a home made machine, a Hobby CNC controller with steppers that I’m running at over voltage but at under their rated amperage. I am running them at full step and they move very smoothly when jogging them or running g-code, Except. ----- I converted a dfx file of lettering, using Mach3 and each letter starts being routed in the middle of the left side. Almost every time I’ve run it, at some point, at a random letter, when it plunges to start the next letter at the correct point (the middle of left side) it will start routing as if that point is the top of the letter and offsets the remainder of the letters down ½ a letter. It is not a g-code problem because it is random at which letter it does this using the same file. I also hear no skipping of steps of the motor. And it plunges in the correct spot according to the code but looking at the Y DRO, after I see it has messed up, it is off by about 1 ½ “ (routing 3” letters). So, it plunges in the correct spot, but then moves –Y about 1 ½” to get to where it’s supposed to be to start the letter, and continues from there.
It does this 2 out of three times.
Any suggestion of what to look far would be appreciated.

Here’s a section of code typical of where it stops one letter and starts another:
G1 X7.3352 Y1.3604
G0 Z0.250000
G0 X7.8158 Y2.5113
F15.000G1 Z-0.1250
F12.000G1 X8.1944 Y2.4754
G1 X8.2350 Y2.5113

The letter height is from apx... Y1.0922, to Y3.9274

Louis