Fiber laser rotary

[Gary Hair]

If you have any problems with image quality on your fiber using the rotary, try changing the steps per revolution. They come from the factory set to 6,400 and for most purposes that would be fine. I'm working on some large diameter pieces and have been seeing a lot of issues with what I'll call bouncing - the rotary turns to mark the next segment and instead of completely stopping, it bounces back and forth a bit. This is causing the edges of the engraving to look like they do when you have backlash issues. So, after lots of experimentation with every setting I could find, even swapping out steppers, I decided to change the steps per revolution. I started with 12,800 and it was much better, then changed to 25,600 and it was virtually perfect! It doesn't change the lasering time by much but it is very noticeable when it's turning a long distance. However, it is smooth as you can possibly imagine, especially compared to when it was set to 6,400. This involves changing the jumper on the driver as well as a software change, total to do both is less than 1 minute. If I ever need to do small diameter parts I'll probably change it back, or lower at least, but for now I'll leave it as is.

[Jesse Wheeler]

Is "steps per rotation" the same as "pulses per round"? I remember you made a post a while back about setting the pulses per round based on engraving a line the exact diameter of your object and adjusting the PPR until the ends of the line aligned perfectly end to end with no overlap.

I'm not sure if it's been covered here before, but I was having the same issues with "backlash", from the rotary wobbling a bit when it jumped between letters engraving text. The only way I could fix it was to increase the "start mark delay" until it was enough for the rotary to stop wobbling after a move. Problem with this way is that when you engrave in uni-directional hatch, the laser is starting thousands of times, so even 50ms delay was enough to increase engraving time by 30% or more. What I do now is draw a line parallel with the image I'm engraving and set the power for that line to 0. That way the laser "looks" at the line the whole time so the laser no longer makes the jump between letters and I can run at full speed.

[Gary Hair]

Steps per rotation is a value you set on the driver that runs the rotary and it is how many step pulses the driver sends to the stepper to complete 360 degrees. Pulses per round should be the same value but can vary depending on the motor. If for some reason the motor turns less, or more, than the driver thinks it should then you can adjust that with the pulses per round.

Steps per rotation is a fixed value set by jumpers on the driver and pulses per round is variable.

[Kev Williams]

So, where is the driver and jumpers-- you talking inside the machine?

[Gary Hair]

Yep, it's inside. Not sure exactly where to look in your particular machine but you are looking for something connected to the plug for your rotary. You'll likely have 7 or 8 switches on it, 3 or 4 for current settings and 4 for steps.