ABS Marking

Lasers
1

I need to make some precise text marking on a white ABS part. I did some research and the best laser for that is a UV laser apparently ($$$$$) followed by a fiber laser ($$$$). It looks like ABS plastic is ideal for marking with those lasers, resulting in a very nice black over the white. The UV simply modifies the color, the fiber does a bit of burning (5% to 10% is what was described - but not sure what that is a percentage of).

Has anyone tried marking on ABS plastic with a CO2 laser? In particular the K40 ($$)?

2

I haven’t tried white ABS but I suspect it’s not going to color change much. UV diode laser engravers can actually be fairly inexpensive depending on the power and bed size required.

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3

Yeah, a cursory look indicates that most laser marking of white abs is usually done with a fiber laser which has a 1.06 micron wavelength. A CO2 laser primarily operates at a 10.6 micron wavelength. Apparently one of the chemicals in ABS (not sure which one) turns black (degrades) at the lower wavelength. UV laser engravers are typically of the 355 nm (0.355 micron) wavelength which is much closer to that of a fiber laser then to a CO2 laser.

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4

Thanks Ned. Any tips on finding a UV laser engraver that is not $5000+ ? Sorry, I am new to the topic of laser engraving and after spending 6 hours looking yesterday, I came out with nothing - everything was really expensive. Fiber laser at a reasonable price would be good too.

5

What resolution do you need for your application?

6

Blue Laser diodes are 420-499 nm is that close enough?

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7

After taking a bit of dive into the literature it seems that ABS is prone to photo and thermal oxidative degradation. This means that shorter wavelengths are probably better but longer wavelengths can work as well. The color change may also be related to changes in TiO2 which is the pigment commonly used in white ABS.

Would be interesting to see what a engraving by a CO2 laser on white ABS would look like if someone with a CO2 laser has some white ABS laying around.

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8

I’ll do it, I have both.

I will post my results :+1:

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9

And the results are :

Rastered at 160mm/s, the one of the left was 8ma, the one on the right 15ma -

16074298477362635031836257179116
160742984773626350318362571791163000Ă—4000 2.1 MB

Fill density on the block was 60%. It doesn’t look particularly good as a finish.

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10

Thanks Jammy you rock! About what I was thinking would happen, but wanted to check. Seems dark marking will only work at lower wavelengths.

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11

The trick will be to find an additive coating which translates to black when a CO2 laser heats it. Much like how white paint on a white ceramic tile becomes embedded black.

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12

Wondering can you fill with black to get what you want???

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Come on boys… give me the challenge… got lots of white ABS.

Cant see a coat of something you can rub off though :thinking:

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Just like marking metal, moly grease and wash it off with a solvent that doesn’t dissolve ABS?

15

While you can get Molybdenum disulfide to bond to metal with a CO2 laser, not sure it would work on the same on plastic without just vaporizing the plastic. If anything you could try a thin coat of dry moly lubricant and engrave at very low power to see if you could melt infuse some into the plastic.

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