Hi Folks, after running our new laser for about 10 weeks, and really testing it out, I've found some issues that the helpful Chinese sellers have been as stumped with as I have.
IN a nutshell, it engraves/scans/etches beautifully, via RD Works, and also via Lightburn.
I have that tuned down well, and the 10 x 4 ft file I spent 16 hours running on our Goldenlaser last Jaunary/Feb, etching acrylic, I decided to run as a test on cardboard on this machine and it did it in just 9 hours, in one piece- no splitting the file into 24 separate pieces because of memory issues. I am happy with that aspect. It took a bit to get the reverse interval calculations spot-on, but they're good now. I can engrave a solid box shape and get no curtains effects at all- just a nice even etch.
As far as cutting goes, therein lies the problem. It has a big gantry with 2 tubes and 2 heads and both steppers in it. X movement is fine - it only has to move the 2 heads.
In Y direction, when I cut circles or squares, (or letters) there is a noticable wobble or vibration as the gantry or Y moves towards the front.
I mean in a circle, it shows up as a wobble in the 1 to 3 o'clock quadrant.
IN a square, it is dead quiet when cutting along the X axis, and the Y axis moving away is a slight noise, but when Y moves toward the front you can hear a grinding sort of rumble.
I'd describe it like the grumbling noise from a servo that does not have the PID settings right, and it is arguing with itself trying to hold itself still.
It's not that bad, but that's what it's like.
I have really dropped the speed and acceleration in the vendor settings and the User cutting acc & speed settings right down extremely low, and that has reduced 96% of the wobble, but it is still not quite right or good enough for my liking.
It should not make a resisting noice when Y comes forward, but no noise in reverse. Logic says the effort or load on the stepper should be the same both ways...
The effects are the same whether I cut a file in the any corner or middle of the bed.
Any ideas would be appreciated. The pulleys/gears are tight, not slipping, and the timing belt is as taut as a guitar string. It is not a physical problem that I can see. There is no perceptible slop in Y. The gantry has no perceptible flex.
Most of my parameters/figures are way less than many think I should have them, but I figured the inertia of the gentry takes some slowing and reversing, so I did not want idle speed and acceleration too high if it has to be resisted at the other end of the journey before the next cut.
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As an aside, I asked for the laser to be built with servos. They said the cost would be too high, and that steppers are fine, so I asked for closed-loop steppers - Leadshine easyservos. They installed them, and it seemed all was good- fast engraving.
They then set the machine to cut a file and then turned the tubes off and ran it in random paths for 48 hours, and then reran the original cut file
The result was they said the easyservos couldn not handle the weight of the gantry and objected to losing steps when changing quickly.
They put the steppers back in. I asked if they could have one of each- easyservo for X and stepper for Y. They said no - they had to be the same type.
So I asked if they'd send the easyservos & drives out with the machine - that cost me about $350 extra, but I now have them to use on another project one day.
So, I'm happy with the machine, and what it has simplified that out that the other two could not do, but I'd be a lot happier if i could solve the grumbling bumpy Y axis movements toward the front of the bed. At very low speeds they are imperceptible to any customer, but it's not good enough for me!
Thanks for any thoughts- does anyone here have a similar system they'd share vendor and user parameters with me over?