What is the Current State of MOPA Color Laser Etching?

[Scott Memmer]

I found an older thread on here from three years ago, but would love to hear an update from anyone knowledgeable about this topic.

I have a need to apply a lime green image of my company's logo on plastic. I had hoped that the MOPA Fiber laser technology had come along enough to do this, but I hear a lot of iffy reports from the field. Could someone give me the current state of the art on this approach?

I cannot do any other color. So if color laser is not happening I have to find another solution.

Thanks,
Scott

[Kev Williams]

Fiber's in general are iffy on plastics. And best I can tell, MOPA's color capabilities are pretty much confined to metals, but don't quote me on that, I'm basing my 'knowledge' on the fact that I can't remember anyone with a MOPA mentioning engraving plastics with it.. ;)

Some of my experiences with plastics: Delrin- some black Delrin engraves a nice light tan, but requires low power and high speeds or it'll melt; some black delrin just melts period... I have some white Delrin, and no matter what I do, my fibers do absolutely nothing to it-? Engraving plastics, some of it works but I can't get it to burn consistently...Cast acrylic will etch nicely IF it's fully opaque. The colors will be variations of the original color, as in, blue will go different shades of lighter blue...
-and this thing is done on opaque black plex:
456952
-but it's essentially 'grayscale'.

MAYBE a MOPA could change those colors on plex, but I don't really know...

[Matt Schrum]

Kev is spot on. MOPA can laser various colors on metal only-- and even then it's relatively slow and I've seen some folks pulling out their hair as batches of the "same" metal won't behave the same when it comes to reproducing the color.

Marking plastics, you're either going to vaporize, burn, or foam (depends on the plastic and your settings)-- or that's all I am familiar with. You can vaporize for texture with minimal color change, foaming (think of the plastic heating and bubbling up) generally results in a lighter color, burning results in a darker color.

I can get gray text on some white and pink plastics pretty easily, foaming is usually a white-ish or a lighter shade of the plastic, and burning is generally bronze colors. Regardless, definitely no lime green.

[Glen Monaghan]

Given such a specific color requirement, applying ink/paint is probably your best bet. Depending on volume and quality requirements, some possibilities are stamping (create the stamp on your laser :^) or pad printing, silk screening, and UV printing. My choice would probably be UV printing (but I happen to have a UV printer so there is that bias ;^)

[Josh Barclay]

I think you need to find another solution. AFAIK color marking is only on reactive metals, such as stainless, titanium, and niobium. Here is a grid I did on Ti.

https://cdn.shopify.com/s/files/1/0186/8444/4772/files/20181012_124951_large.jpg?v=1551014917