Chewabarka Tags Lasering more White

[Bill George]

I have been using their tags for years, and in the past I used my fiber laser and they looked great. Now I just have my CO2 40 watt Chinese machine. The lasered text looks off white or a very very light shade of gray. I have emailed them and not heard back. So is that just the way it is or has someone actually done them and had them come out white?


https://www.chewbarka.com

[Scott Shepherd]

Just the difference in fiber and CO2. Fiber will always be whiter and brighter on anodized aluminum.

[Bill George]

Well I got a reply from them, with some settings to try and no difference. Scott this just takes off the color and underneath is white, not bare aluminum. They are made to work in a CO2 laser.

[Tony Lenkic]

Bill,

Chewbarka tags are anodized tags not painted,
Do you have a part # for painted tags?

[Bill George]

Look for the business size metal cards. Even the dog tags that a colored have the white under the color. I have been using for years. BTW I know they are not painted.

http://chewbarka.com/name-plates-and-business-cards-c-36/?zenid=5utmuchn2eg7unmqo1avj0iqb3

[Scott Shepherd]

What do you mean they have white under the anodizing? The laser bleaches the dye white. There is no process to put white under anodizing that I am aware of. If they are anodized them the fiber and CO2 will handle them differently. The fiber is always going to be whiter, the CO2 more gray.

[Bert McMahan]

Scott, there are differences in anodizing processes that can make the underlying substrate more white than gray (in other words, the basic color that you get if you don't dye the part). It's not **WHITE** but there are color variations you can get with different alloys, baths, plating times, etc.

[Kev Williams]

What Steve said... under the colored coating is clear anodized aluminum, which is whiter than raw aluminum, but still not white, C02 lasers just turn clear anodized white like they do colored anodized, and typically it's a whiter white since there's no dye to remove. To be sure, C02 lasers do in fact 'engrave' anodized aluminum- or more accurately, they don't engrave aluminum, they engrave aluminum oxide, pretty much the same way they engrave glass...

Fiber lasers engrave away the aluminum oxide altogether AND the aluminum below- depending on the thickness of the oxide layer, fibers can have a tough time getting thru it. Typical anodizing is pretty easy...

The white engraving a fiber achieves is (IMO) due to aluminum's natural reflectiveness, enhanced by the engraved hatch lines, which creates more surface area to reflect light. High speed low power cleanup passes enhance the white by 'polishing' the cut. If you hit aluminum with low speed mid-frequency high power passes with a much tighter hatch fill you end up with gray instead of white; the extra heat discolors the aluminum and a tighter hatch and frequency mottles the engraving.

My fiber laser on black anodized in gray and white, the gray is discolored and
mottled, the white's hatch lines really grab the light-
note that the gray appears darker in the smaller pic, more contrast to the naked eye-
406782406783


My LS900's version the gray is 50% and done via pure photo mode. (bars are about 3/8" tall)
As you can see, the white side is has actually engraved the oxide, but only the oxide,
this is why clear anodized will go white, if the oxide didn't engrave nothing would happen...
- the white looks fairly white in the big pic, but really, it's not even close to the fiber's white-
Zoomed out it's even more apparent... dinjy tannish-gray ;)
406785406784
--and the gray would've come out better using normal engraving and lower power...

[Bill George]

But since the ratio of CO2 lasers vs fiber may be what? 50 or 100 to 1 and they are marketing as laser engrave able I can not be the only one with issues? More power does nothing except start to turn it brown or tan. I had better luck using with my 40 watt 20 to 25% power and about 1/2 speed. Yes, agreed the hatching in the letters with the fiber makes the white letting Pop out. Only wish I could figure that out with CO2 and Corel Draw.

[Chris DeGerolamo]

But since the ratio of CO2 lasers vs fiber may be what? 50 or 100 to 1 and they are marketing as laser engrave able I can not be the only one with issues? More power does nothing except start to turn it brown or tan. I had better luck using with my 40 watt 20 to 25% power and about 1/2 speed. Yes, agreed the hatching in the letters with the fiber makes the white letting Pop out. Only wish I could figure that out with CO2 and Corel Draw.

As you stated more power is not the solution. When we do production AA, I run [our CO2] at 600DPI, 100P, 100S or 90/90 depending on content; thinner content needs longer dwell time to produce a brighter mark. Have you tried running Stucki or Jarvis algos?

I am coming in late to the thread, but can you also rule out out-gassing of your CO2 tube?