Glass engraving is getting on my nerves

Community Laser Talk
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Hi guys,

Currently running into some issues when engraving glass, hopefully somebody has a good tip for the situation I’m in, let me give you a little backstory first:

I run a shop in personalized items, I want to add glasses to my inventory, meaning I will have 8-10 different glasses that I will engrave with a design that is supplied by a customer. These are not big orders, meaning I want to be able to switch out designs and glasses as fast as possible and make it a ‘standardized’ process (sort of). For this to work I need optimum settings for engraving glass ofcourse, I’m currently running a 50W CO2 with a rotary and already have been spending several hours testing what is (and isn’t) working.

So far so good, but here comes the problem. I thought I had a Eureka-moment and found the perfect settings. These pictures aren’t great, but hopefully they will give you some context:

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This is a champagneglass with what I believe to be a fairly good engraving. The engraving isn’t chipped, frosting looks nice, overall I’m happy. Got this results after testing various speeds, dpi, power, gray-scales and coatings (wet paper, transfertape and detergent). I was as happy as I could be.

Then, for testing purposes, I tried engraving a different design with the same settings, and it turned out like this:

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Here there’s two names that look acceptable (not great, but only need some finetuning). However, the circle that goes around it hasn’t even engraved properly (don’t mind the warping for now).

The circle around it is basically a very thin line with some details, but whatever I do I can’t get it to engrave properly while also having the names inside without chips or flakes. Engraving the circle separately isn’t really an option here, does anyone know what direct to go in from here? Or is there just no sweet spot for ‘all’ designs, because that would mean that for every design I’d have to make a testrun first.

Feels like I was already at the top of mt Everest and someone kicked me back halfway :sweat_smile:

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The power supply and laser tube require some time to reach the commanded power, so engraving a very narrow line at very high speed may require faster response than the laser can deliver. The wider letters allow enough time to reach the commanded power, so they engrave better.

If that’s what causes the problem, you must reduce the engraving speed to allow the beam to reach the power required to produce the right results in the fine lines. Just increasing the power won’t help, because that will over-burn the letters.

Doing the lines and letters in two separate layers with different settings would be the right solution, but will cut your production rate in half. I can see why you reject that. :grin:

1 Like
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Thanks for taking the time to comment. That definitely sounds like something that could do the trick, I will try this in the next few hours.

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I use painters tape over the burn area when engraving glass… sounds strange but I find less chipping in the engraving. Normal green painters tape. It just evaporates off the engraved areas. It can be a hassle to pick off afterwards but they can also be washed with soapy water… small tape remnants just wash off.

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Yes, unfortunately I already tried all maksing options I know of. Painters tape/transferpaper, wet towel, detergent/soap, newspaper, you name it. Each has their own way of working, but unfortunately none of them seem to solve my issue. Im currently working on dialing the speed wayyyyyy down. I’m not there yet, but the results look promising.

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perhaps multiple passes ? I have had some issues with odd shapes not aligning well for second pass due to inconsistency in shape/diameter etc. I did some dark glass beer bottles for a local brewery and that glass gave me loads of problems. I had to run three passes to get a nice engraving… It chipped and flaked and had hard spots that took more laser power… real headache.