XY table set up parameters

[Art Krenzel]

I have had a Chinese CO2 laser (CNCOLETECH) Model 9060 for two+ years now. I have complained over that time to Shirley (who monitors this forum) that the apparent velocity of my X & Y heads differ significantly. Their solution was that I should draw a square on the software and one on a target piece and run the program. Using a micrometer, I should make arbitrary corrections to my X or Y move commands until they "seemed" equal. I complained that the XY table is a precision unit made of standard components in a production line. It has X & Y input values of up to eleven places behind the decimal point and that the pencil and ruler method of setting it up was unacceptible to me. Several more requests for the XY values which they use to set up their Model 9060 Laser Engravers before shipment have been made but there are no more reply emails.

So I was wondering if there was anyone out there who has a Model 9060 Laser Engraver from COLETECH that I might compare software values from my XY Options page to see how far my machine might be off?

Please give me a call at (360)666-1883 if you have one. Art

[Glen Monaghan]

I can't help you with that, but since you aren't getting the desired info from the company, what's the harm in at least trying their "stone knives and bearskins" approach? It'll get you farther in less time than waiting on more non-responsiveness, and it might even produce results that are "good enough"...

-Glen

[Rich Harman]

Do the math.

First you need to know how many steps are required to make one revolution of the motor. My drivers are set to 5000 steps/rev.

Then you need to know the ratio of the pulleys. Mine is set up with a 20 tooth pulley on the motor which drives a 40 tooth sprocket. On the same shaft as the 40 tooth is a 20 tooth sprocket which drives the belt that connects directly to the axis.

So now we have 10,000 steps to turn the final output shaft one revolution. The final pulley is 20 tooth and the belt is 3mm pitch. So one revolution equals 60mm of travel.

60mm travel / 10,000 steps equals .006mm or 6.00000um.

6.00000 is the correct setting for my machine.




However, it still was not perfect. I discovered through much trial and error and speculation that the culprit was a stretched belt. It was possible to alter the step length to make a 100mm square perfect but then a 400mm square would be off, and vice versa. I have since replaced the belt (and pulleys) with a 5mm pitch 16mm wide AT5 belt. Now it is perfect. My step length is 6.0000* as it should be and a 100mm square is 100mm and a 400mm square is 400.




*it is actually something different since my new output pulley is a slightly different diameter so I left it at 6.0000 to avoid confusion.

[Rodne Gold]

Every single laser I have owned , chinese or not , need that compensation. Most have internal "correction" in their software. You draw a square , measure it , input your measured values to the expected values and it changes its own X/Y steps/whatever. It's not a phenomenon that's uncommon. Look at your software to check if you have that function , if not , you have to do it by changing the steps per inch of the relavant axes.

[AL Ursich]

Since we are talking Encoders and that conversion between Shaft Rotation and the number of pulses per revolution. Here are some pictures of my CarveWright Servo Motor Encoders. :eek:

It's not a Laser but I thought a Visual was in order since I have learned a few things from this post. The Stretched Belt is good to know about....

The CarveWright Encoders can get Sawdust inside and inspected from time to time..... :mad::rolleyes:

AL