Rotary Tool Troubleshooting Request

[rencheple (Tim Martin)]

I am sorry that it seems I only come here when I am utterly stumped. When I feel I’ve improved at this, I may feel comfortable offering some answers and feedback.

I need some help with my rotary engraving. I am using the Elegoo Phecda laser engraver with the Elegoo rotary attachment. It took me a while to get the rotary settings to what I thought was correct, verifying them against a 10 cm grid on a relatively cylindrical thermal mug. Aside from some drifting, it seemed okay.

I then wasted the other three mugs in the set trying to do an engraving for my son, who’s down at Fort Gordon in Augusta, GA. Every time, there were artifacts I couldn’t explain; I’m hoping you all can.

Mug Engraving Test.lbrn2 (17.0 KB)
Here’s the test I was doing.

Here are the two different settings. I was testing both line engraving and bidirectional fill.

And finally, here was the result.

The boxes seemed okay, all considered. They are consistently 10cm x 10cm. The word is much wider than it should be. The “up/down” letters are the proper width and engraved okay, aside from the space between the letters. Note that the space is correct if you consider the space of the “up/down” engraving to the “horizontal” engraving of the next letter, as between the T and E above.

Is there anyone out there that can advise on how to address this? I feel the issue must be in the rotary settings, but I can’t figure out where I went wrong.

Thank you in advance.

Tim

[jkwilborn (Jack Wilborn)]

You machine speed is maximum 25000mm/m according to the manufacturer. That is 25000/60 is 416mm/s… 500mm/s is faster than it’s manufacture states as it’s maximum.

All controllers have speed limits in place so you do not try to run faster than is safe for the machine.

I’d suggest lowering the speed and compensating power for a change in speed.

If you have cross hatch enabled, I would run with only a fill operation, disable cross hatch.

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Looking closely at the output, the interval is probably to high for a good engrave. Again, the manufacturer states the spot size is 0.07mm X 0.13mm focal spot for the 20W module. A 0.10mm interval will leave a gap between scans in the 0.07mm direction as it’s smaller than the interval.

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This video by Laser Everything on photo engraving explains how to pick the best interval, well worth the watch. It’s done on a fiber, but the technique works with any laser and any material.

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You output looks like it’s been done more than once…?

It’s very easy for these to slip.

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On my rotary, I have some wide black masking tape. I tape up the object and make a run at very low power. Enough to mark the tape but not the object.

Good luck