Cermark Laser Marking Paste – Inconsistent Results

[Mark Langston]

I am trying to mark 0.040” thick anodized aluminum using Cermark LMM-6060 Metal Marking Paste.

Some of my letters look dark while others right next to them are light.

Specifics:

• I am mixing 1 part paste with 1 part denatured alcohol.
• I spread the paste on the aluminum until there is no aluminum showing through.
• I let it dry for 15 minutes.
• I have an 80 Watt Trotec Speedy 400.
• I engrave the paste at Power: 100, Speed: 1, Resolution: 1000.

What speeds do you guys use to get good results?

[Gary Hair]

First, you need to thin it more and spray it on. Others have success with brushing but I was never able to get a thin, even coat by brushing. Even if you don't spray it you still need to thin it more, probably at least 5:1 and up to 10:1 - 1:1 is too thick. You want something the consistency of milk. Second, you are applying too much if you can't see the substrate. When I airbrush it on you can still (barely) see the shine of the metal underneath. If you apply it thin enough it will dry in less than a minute, if it takes 15 minutes to dry then you have way too much brushed on.

I'm still getting used to the settings on my Speedy 400, but for my 30 watt Explorer I used 100% power, 10% speed (which equates to about 8ips) and 600 dpi. An 80 watt machine should be running fairly fast to match those settings, so speed of 1 is probably way too slow. You could reduce the resolution to around 600 and still get great results, at 1,000 you would have to speed it up even more to avoid hitting it with too much power.

Edit: the fact that you are marking aluminum is also problematic. I never had consistent results on anything but stainless steel. Now that I have 80 watts I might give it a try, but my fiber has pretty much eliminated my use of Cermark...

I am trying to mark 0.040” thick anodized aluminum using Cermark LMM-6060 Metal Marking Paste.

Some of my letters look dark while others right next to them are light.

Specifics:

• I am mixing 1 part paste with 1 part denatured alcohol.
• I spread the paste on the aluminum until there is no aluminum showing through.
• I let it dry for 15 minutes.
• I have an 80 Watt Trotec Speedy 400.
• I engrave the paste at Power: 100, Speed: 1, Resolution: 1000.

What speeds do you guys use to get good results?

[Ross Moshinsky]

As far as I know, you can't mark anodized aluminum with Cermark until you remove the anodizing. Cermark only works on raw metal.

[Gary Hair]

anodized aluminum

I completely missed this part of your question. Forget everything I posted. If you want a black mark on anodized aluminum you'll have to blast through the anodized layer with a fiber and then oxidize it. I do that all the time. No way to do it with a co2.

[Mark Langston]

Thanks for replying. Yeah, I'm looking into get a fiber laser as well for marking aluminum and for part marking somewhat deep.

I had no idea that I had to dilute the paste that much! I will try your suggestions. I have been using thermal tape with success, but it is a pain to clean. Washing paste off is so much easier.

[Mark Langston]

I completely missed this part of your question. Forget everything I posted. If you want a black mark on anodized aluminum you'll have to blast through the anodized layer with a fiber and then oxidize it. I do that all the time. No way to do it with a co2.

Well, there's my problem. Thanks for replying.

[Mark Langston]

As far as I know, you can't mark anodized aluminum with Cermark until you remove the anodizing. Cermark only works on raw metal.

I have struggled with this for so long. Now I am learning. Thanks!

[Keith Colson]

I just tried marking some natural anodized aluminium with my 60 watt c02 and it works fine. I tried two methods.

1) I burnt off the anodize in one pass. I applied some Cermark and reran another pass.

2) I burnt off the anodize and then applied some aluminium blackening fluid.

Both came out a dark grey, no where near black but both looked clean and had plenty of contrast. I think the fluid came out slightly more even. It is better as you only need to run the laser once.

[Mark Langston]

[QUOTE=Keith Colson;2454421]I just tried marking some natural anodized aluminium with my 60 watt c02 and it works fine. I tried two methods.

1) I burnt off the anodize in one pass. I applied some Cermark and reran another pass.
QUOTE]

What settings did you use to burn off the anodization? That's a good ideas!

[Kev Williams]

The problem with burning off the anodizing is, one day it will burn off fine, then when you take on a 100 plate job you find out it doesn't want to burn off for love nor money...

However, this issue crops up more with having anodizing done at a plating shop, due to the batches and dunk times always varying.

If you buy 'brand name' pre-anodized aluminum, you should get good, consistent results. Because (a) the anodizing is done fairly lightly, and (b) strict recipes are usually followed for consistency.

I love the 'brand name' aluminum, my only issue is it's easy to burn thru the anodizing if you're not careful. I have black anodized aluminum made from scratch, and my 40w LS900 will NOT burn thru the anodizing no matter how hard I try. My 80w chinese Triumph will, but not consistently. A couple of months ago I tried to get black engraving on some clear anodized aluminum cans (my customer anodizes in-house). My Triumph would not go thru the anodizing enough for a cermark followup, even at ridiculously slow speeds. I could get the can so hot I couldn't pick it up just engraving a line of 1/4" text, but still not enough bare metal would expose for cermark to work. And Aloxide didn't fare much better when I tried it.

[Gary Hair]

The problem with burning off the anodizing is, one day it will burn off fine, then when you take on a 100 plate job you find out it doesn't want to burn off for love nor money...

Two words: fiber, sandcarving

Either one will solve your problem with consistency and ease of use vs co2 alone.

[Keith Colson]

Mark, my settings to burn off the anodize was 100% power and 10% speed.

[Mark Langston]

Sounds like my issues.

[Mark Langston]

Thanks, Keith. I will try those settings.

[Keith Colson]

One thing I should have noted. If your machine is not well focused and I mean calibrated when I say this. You can expect poor results.