NEED HELP! - 60W 700x500 Y-Axis Missing Steps

[SpierceTech]

Hi All,

I've been running a K40 that I upgraded with a DSP and Z table for a couple and I just bought a RedSail (Clone?) off eBay (60W CO2 Laser ENGRAVER Top Line Laser Engraving Machine Comes w USB Interface | eBay). It arrived well packaged and I got it set up and running but the Y-Axis seems to be missing steps during rapid and jog movements. When cutting a test square 1/2" x 1/2" out of 1/8 plywood, the length and width are within about .001-.002" of each other. It's only when rapid moving a few inches does the Y-Axis lose accuracy. Here are a couple pictures to illustrate the issue:



The places where the spacing between the test squares varies is where there was a rapid movement of more than an inch or two. I can set the home position of the machine, fire the laser to mark the spot, then jog the head in the Y-Axis and then send it back home and re-fire the laser and it'll be up to 1/8" or so off. Sometimes more, sometimes less.

The things I have tested are:

1. Make sure 24V is going to the stepper motor drivers - Voltage was 23.74V, I adjusted it to 24V
2. Swap the X and Y stepper motor drivers - the issue still remained with the Y-Axis and did not transfer to the X-Axis.
3. Checked the set screws that hold the pulleys on the Y-Axis drive shaft. I was able to get less than a quarter turn more out of each screw. This did not fix the problem.
4. No audible skipping is heard from belt slipping and the belts seem to be tight
5. Y-Axis seems a little stiff but not any more stiff than the X-Axis

And help you guys can provide is greatly appreciated!

Thanks!
Scott Pierce

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[gfacer]

Check the acceleration settings, and reduce Y's settings and see what happens. What speed was the rapid at?

[gfacer]

Check your Y acceleration....you will need the vendor password (well, that's how it works on mine, not a redsail) to read the settings off the machine, change and write back. Look at what your Y rapid speed is, that could be the problem too.

[SpierceTech]

Sorry to reply to my own post but wouldn't you know it....two minutes after I submit the question, I figured the problem out. The Y-Axis stepper motor pulley was shipped without set screws in it which allowed the pulley to free wheel on the motor shaft. I pulled a set screw from another pulley that had 2 set screws and put it on the Y axis pulley and that fixed the problem. I'll order more 4mm set screws and make sure all pulleys have 2 set screws in them.

[SpierceTech]

Sorry to reply to my own post but wouldn't you know it....two minutes after I submit the question, I figured the problem out. The Y-Axis stepper motor pulley was shipped without set screws in it which allowed the pulley to free wheel on the motor shaft. I pulled a set screw from another pulley that had 2 set screws and put it on the Y axis pulley and that fixed the problem. I'll order more 4mm set screws and make sure all pulleys have 2 set screws in them.