On my 100W OMTech CO2, I’m burning tumblers on a wheel style rotary. Problem is I go through all the effort of skewing my image for both taper and wrap to get a round image look round on a curved surface and sometimes the proper image gets burned and sometimes it’s like I didn’t do any of that modification. I’ve got a lot of scrap tumblers because of this.
This week I did 6 tumblers for a business…3x blue, 2x red, and 1x black. After my test image came out perfect I just put a same-colored tumbler on and hit the RUIDA “Start/Pause” button. That usually just runs the last job over again but this new tumbler was really screwed up. Logo not nearly round and not like an unmodified logo either.
I tried another test piece, hitting start from the computer and again it came out perfect. Next one started from the computer was as if I burned an unmodified logo as it didn’t account for wrap length and didn’t look round. I said the heck with it and just decided to run them as is. The next two were the same (acceptable), but when I changed the power setting for blue (highest power of the three colors) the images were properly skewed and look round when viewing from straight ahead. What the heck is going on?
In the attached picture the blue tumblers turned out proper (logo widened to appear circular on curved surface), and on the red and black tumblers they appear as if it were the original image. Nothing changed except the power settings and names changed on the opposite side. I’m so confused… If they were all 6 the same I wouldn’t worry about it as much, but two different image widths looks pretty unprofessional if they are right beside each other.
After getting the three blue ones to look proper, I loaded up a new black tumbler with black power settings to re-do and it turned out just like the original black one…not correct.
This isn’t the only time I’ve had this happen on tumblers, but other times I just kept trying things on setup pieces until I got the width and skew to look right. Those other ones were one-offs and didn’t constitute a 50% scrap rate like this job did.
What do I need to do to get consistent results? Is there something on the Lightburn end of things I’m doing or not doing that gives this variable output?
Are you using a chuck style rotary? Or is it a roller style one ? It looks like the machine is working properly but there is an alignment issue. Perhaps they are not rolling 100% true and causing some distortion. I have had this happen with my roller rotary where it just has a slight wobble as it turns. A chuck may have worked better for me for those… although a chuck can be harder to center and can also add some complexity. Keeping your item centered is key for sure.
Can you please post pictures of the ones that turned out correctly… also perhaps some pics of the rotary setup and lightburn file. There are some smarter people than myself on the forum that can spot errors better than I.
I think the one on the left is correct, the right one has issues…
Appears to be a wheel or roller type…
The only difference I can think of is color but the results don’t support what I know about how the Ruida works… it should be executing the same code for the next run…
However he did mention that he changes his power settings when he changes the mug color…
With his machine, I wouldn’t think power would be a problem, but it’s not the same code as the description… he would have to change it at the console… then it would over ride the stored settings…
Whenever this happens, the problem generally boils down to something else changing, always unintentionally. Discovering the cause requires breaking the “didn’t change” and “doesn’t matter” assumptions.
The first step is to test with simple, cheap, cylindrical objects, rather than an assortment of tapered mugs. Find several identical cylindrical metal cans or bottles about the same size as those mugs: stupid-big beer cans or something from the canned food aisle will work. Leave the cans full and wrap them in heavy paper or light cardboard (@jkwilborn uses black tape) so you can watch what happens.
Hitting a pressurized plastic beer bottle with a CO₂ laser would be interesting, but wrapping aluminum foil under the paper will be better.
Run a file that produces inconsistent results on tumblers, but now use cans.
If the file is consistent on cans, contrary to what happens on tumblers, then the tumblers are slip-sliding away on the rollers or the roller drive has problems. Report back and folks around here can help figure out what’s causing the problem: fix it and you’re done.
If the file produces irregular results on the cans, then something interesting is happening and it’ll take a bit more investigation. In that case, uploading the file will let other folks around here poke into the details and suggest solutions.
