Laser not firing in places on design

This does not provide enough information about settings (if they were provided in relation to this issue). And I can only assume that you mean 50mm / second. Is this correct? But it it does provide at least some.

My suggestions will be a guess because of this except for recommending that you use more power and faster speed on your job. On a 140w laser, I would run an an engraving job on similar tumblers on min/ max 20% power at about 10" (255mm) / second. Running slower can have disadvantages (not just taking longer but other things like heat gain, reflection, softened lines etc when taking off that powder coating from a stainless tumbler).

The good news is, now you have a test tumbler to practice settings and positioning on forever. And, after you have “tested it out” (used up all of the real estate on the outer surface), just create an erase job to clear away the entire surface of powder coating. Now you have a great opportunity to experiment with powder coating (and reviving that tumbler back into a test subject).

Assuming you have your machine properly calibrated, I would recommend your power be at 50% with speed at 255 mm / sec. If this is too fast for your hardware, then 25% at 125mm / sec. Don’t go below 25% on your machine for these tumblers (even if you have to decrease your speed down from 125mm sec). And always apply / use a mask on your tumblers until you really lock in the settings and are comfortable that you don’t cause ghosting.

Also familiarize yourself (if you have not already) with Ruida’s start speed and the effect of this in relation to min / max power settings. If you do not understand how these settings relate to your job, I recommend that you have min and max power setting the same.