HI, we've had our big 2-head, 2-tube laser a few years now, and after a lot of tweaking, I'm mostly very happy with it.
I saved the vendor settings right at the beginning, although they're pretty useless - the chinese mob who set it up were very good, but things like reverse interval settings etc, and small circle speed limits were not a part of their expertise.
For a long while I had slight start and end cut alignment issues - fixed by minor tweaks to backlash.
Engraving is great. Cutting is another matter. For anything say 35mm high or bigger, cutting is great. It's just very small stuff I'm finding tricky:
I've had 2 jobs recently - diecutting card for a printer - 7000 discs, 3/4" diameter, and 5000 at 1" diameter, set up on A4 sized sheets.
The problem with our big laser has been at that small diameter, the circles are not perfectly circular.
They all have a slight flat-spot at 5-past 12, and 35-past, or between 12 and 1, and between 6 and 7 o'clock.
The start and ends line up perfectly. If I set a seal of half to 2 mm, (or path overlap) it is imperceptible, which is good.
I did have other issues, mainly being the 'bounce' at the beginning of every cut - a dampened sinewave shape that ceased after about 3 or 4 cycles, which I attributed to the higher acceleration in idle, then slowing down and overshooting the mark as it started each new cut. It did not matter where on the clock the start point was. I had to crank the cut start speed right down low, and the acceleration right down low in order to eliminate the bounce or wobble - read, edit and write to the controller, in User settings.
That made everything pretty slow though.
With the big laser, both tubes - W1 and W8 Reci are carried in the extra-big gantry, so there is a fair bit of inertia to have to shift and absorb - much moreso than smaller bed lasers where the gantry only carries the head and the belt for the head.
I tried turning on and turning off the Backlash Reappy checkmark. All that did was alter the starting place of each new file, and change the total time taken for the jobs due to extra travel time to begin each new cut at the opposite side of the clock. It did not change the flat spot which is like a failure of Y to move microscopically at the direction change time after the head passes 12 o'clock or 6.
When I tried to go faster, we got the bounce at each cut beginning point.
I tested this by lasering lots of concentric circles, not by wrecking the client's job!
IN the end I guessed that although in Vendor settings, Y has a much lower acceleration factor and lower overall speed because it is a bigger Leadshine stepper motor moving a bigger weight, compared with X's stepper which only has to drag the head - that maybe the RD6442 might have problems sending instructions ot 2 different drives with different parameters, and perhaps that's the reason for the flatspot - so I set both X & Y in Vendor settings to the same lower speeds and acceleration as Y used to have.
It sufficed to run this job acceptably - and the resulting discs look round to anyone else, but I still see the minute flats. And minute overcorrection bounce in the curves.
No, the belts are not loose, nor is the lens loose. if I laser a 1200mm square on cardboard, the four sides are accurate, as are the diagonals.
So, I was wondering if anyone else with a machine with a heavyish gantry like ours, might not mind sharing their vendor settings for overall X & Y speeds & accelerations, and User settings for the same, and small circle speed limits please?
It is great at bigger sizes, but I'd like to be able to have it better at the tiny vectors, at a greater speed than snail's pace!
Thanks for any thoughts!