Choice of TherMark/Cermark on aluminum

[Richard Rumancik]

I am trying to mark bare aluminum with Cermark LMM6000 but having poor results. Cermark suggests use of 50 watt machines for aluminum marking but mine is only 30. If I really reduce speed I might be able to get an adequate mark but then I doubt that I can mark a part at a reasonable cost.

I checked the TherMark site and they say:

"Bare, uncoated aluminum normally requires the selection and use of TherMark’s laser marking material LMM14 Black, which is water based and marks in black. For a faster drying marking material, most aluminum needs ethanol-based LMM6000 Black."

Has anybody tried LMM14 on aluminum? Should I expect different results than LMM6000? The above comment suggests that LMM6000 will dry faster than LMM14, but there must be SOME advantage to LMM14 over LMM6000 on aluminum (or they would not offer both). It is not specifically explained as to why one would use LMM14.

[James Stokes]

I engrave a lot of aluminum data tags. I have a 100 watt Epilog. With the Lmm6000 I can not get a mark on aluminum. If I use the Lmm14 I do not have any problem. I run them at 100 power 63 speed and it leaves a good mark. The only thing I do not like about the Lmm14 is it is harder to spray. With a cheap harbor freight air brush I can not mix it thin enough to spray very good. I now use an automotive touch up spray gun and it sprays O.K.
One other thing about it. It does not stick as good as the 6000. If you touch it, it wipes off very easy. I have found a fix for that. If you put a couple drops of Dawn dish washing detergent in it before you start spraying it will stick very good.
As for drying speed I do not notice any differance.

[Shane Turner]

I've used the aerosol can ( can't recall the product code ) of Cermark with very good results on aluminium.
It's not the most cost effective if you do large orders but as I don't do metal marking too often, it is the most convenient.

[Richard Rumancik]

I engrave a lot of aluminum data tags. I have a 100 watt Epilog. With the Lmm6000 I can not get a mark on aluminum. If I use the Lmm14 I do not have any problem. I run them at 100 power 63 speed and it leaves a good mark.

Thanks for this info. At least it suggests that it is possible. If I had to run my 30 watt at 15-20% of my max speed it would still be viable. The viscosity issue you note sounds like a bit of a hitch though. I also use small cheap airbrushes as I don't like to mix too much at a time. However I have an Aztek airbrush - maybe I could get a different nozzle for it that would handle thicker liquid. You are thinning the LMM14 with water, correct?

[George Elston]

My first try with Cermark (LMM-6000) was on an .125 aluminum bar, and not knowing any better I put a small dab into the airbrush jar and filled the jar about a third up with acetone, (the only solvent I had on hand, I mean it was THIN), and gave it a quick spray. To my amazement it marked perfectly and bonded. What I have found since then is that with my 30Wt laser, what seems to work best is a layer that is one grain thick. Every time I have tried thicker layers (two passes with the gun or a sponge brush) it seems like the laser will fuse the top but only to the unfused cermark benieth it, the laser is not strong enough to fuse down to the metal and it rubs right off. I have since marked lots of aluminum, and stainless and as long as I keep it very a very thin coat it works perfect.

just my 2 cents woth

[Mike Null]

Here's a link to a previous response from Sean Weir of Cermark.

http://sawmillcreek.org/showpost.php?p=637784&postcount=7

[James Stokes]

I thin with denatured alcohol.

[Brian Robison]

I tried a while back comparing both, On aluminum I had better results from the Thermark. It was head to head using the same piece of aluminum, same settings on the laser.You'll probably have a hard time running that high of a speed on a 30 watt laser. Sorry.

[Adam Stacey]

I've used LMM6000 in the aerosol can to successfully mark on anodized and raw aluminum. With a 60w Epilog laser, I used 25% speed, 75% power, 600 dpi. I found the dpi setting was important, as if you set it lower it sometimes turns a brown color instead of black.

[Sean Weir]

Hello Richard,

The LMM-14 and the LMM-6000 produce an equivalent mark, but there are some differences in the materials. The key differences are:

1. LMM-14 is water based, LMM-6000 is ethanol based. This means LMM-6000 dries faster, but costs more money for shipping because of the flammability of ethanol.

2. LMM-14 is black in color, LMM-6000 is yellowish. This means LMM-14 will absorb laser energy a little better, so you will need slightly less power (maybe 10% or more on some metals) to make a given mark with 14.

3. LMM-6000 dries to a film, LMM-14 dries to a powder. Parts coated with LMM-6000 can be handled and stored after drying, but LMM-14 will brush off the metal very easily and must be handled very carefully. For example, if you coated both sides of a keychain with LMM-14, it would brush off one side while you were marking the other. If you use LMM-6000, it won't brush off.

Again, both will give you the same end mark result. Some users report that the 6000 gives a darker mark on stainless, but I can't confirm that. To make a long story short, you would have to decide if you need a faster drying rate or the ability to stack precoated parts or be able to handle a coated part without fear of brushing the material off accidentally before marking. If you want these abilities, you need the 6000. Both the 14 and 6000 can be purchased direct from Ferro if you wish.

For power settings, I would recommend running at 100% power and about 2.5 to 5.0% speed. You may even need to run at 1200 DPI. Aluminum is a tough metal to mark, it is a very good conductor of heat and will act as a heat sink during the marking. This means you have to mark slower (more heat) to get a good bond. The LMM-14 may work better for you at a given power setting because it is black, soit will absorb better and make marks at lower powers.

Also, it is important to always apply as thin a coating of the marking material as possible. Thinner is better! Apply only enough coating to hide the surface of the metal underneath. Excess coating will not result in a daarker or better mark, but it will require more power/heat to get a bond.

I hope this information helps, if you have any other questions, please feel free to ask.

Best regards,

Sean

[Eric Allen]

Seems a small thing, but maybe helpful that someone pointed out in the past. They suggested that with materials like Al and Brass that you preheat the metals prior to marking to minimize heat absorption. Wish I could remember the post, don't remember them giving specific temps but it makes a certain amount of sense. I just got my Cermark in today, never really played around with it before. Hoping the LMM6038 has better adhesion on chrome type surfaces as claimed. It certainly costs more, hope it earns it's keep:)

[Richard Rumancik]

Sean, thank you very much for the detailed info. Although some users have suggested that LMM14 will work better on aluminum, you don't seem to be suggesting or guaranteeing that. If I had to run below 5% at high resolution it would mean 20 or 30 minutes for a little panel which makes the cost to my customer rather prohibitive.

I was considering trying LMM14 even though the handling is more difficult . . . but every experiment seems to cost $50 or $100 or more.

Thanks to the other members too that contributed information on this topic.

I think it was Rodne who suggested pre-heating the material. I am going to pursue this approach some more to see if I can get the LMM6000 to work on aluminum at a reasonable speed.

[Sean Weir]

Hello Richard,

Sorry if I didn't completely answer your question, I may have left some info out of that long post.

Although LMM-6000 and LMM-14 would make virtually identical final markings, you should be able to make a mark on a given susbstrate faster with LMM-14. This is because the LMM-14 is a dark color, it absorbs laser energy more efficiently and this allows your to mark at a faster writing speed.

Hope this helps, if you need anything else, please feeel free to ask.

Regards,

Sean

[Pat Berumen]

My first try with Cermark (LMM-6000) was on an .125 aluminum bar, and not knowing any better I put a small dab into the airbrush jar and filled the jar about a third up with acetone, (the only solvent I had on hand, I mean it was THIN), and gave it a quick spray. To my amazement it marked perfectly and bonded. What I have found since then is that with my 30Wt laser, what seems to work best is a layer that is one grain thick. Every time I have tried thicker layers (two passes with the gun or a sponge brush) it seems like the laser will fuse the top but only to the unfused cermark benieth it, the laser is not strong enough to fuse down to the metal and it rubs right off. I have since marked lots of aluminum, and stainless and as long as I keep it very a very thin coat it works perfect.

just my 2 cents woth

I used the aerosol can of LMM 6000 and put a very light coat. Lasered 30w @ 100% power; 1% speed; 1000 PPI. Thanks for the tip. I ran a faster pass at 5% speed and the results looked even better!