Protecting Cermak Coated Items

[Steve McKee]

Okay, this may be a silly question but that's never stopped me before. I'm having an issue with cermark and I'm not sure what the cause might be. The problem is that the cermark isn't adhering as well as I'd like. I've tried different speeds, power settings, etc. with no real improvement. It seems to be doing what it's supposed to do but after a few days it starts to rub off. Okay, now here's the question part, is there something I could spray on, rub on, whatever that would "seal" it to the item? Any suggestion would be appreciated.

Steve

[Randy Digby]

I'm certain I don't have enough experience to accurately answer your question, but in my limited experience I have found that the settings on my machine that give me acceptable results are nowhere near what the supplier (Thermark in my case) gives as a starting point.

When I complete the engraving process, I scrape the residue off with sharp edged laminate (used like a putty knife), I then clean the sticky residue off with a generous application of WD40 followed by a good scrubing with a sponge and hot, soapy water. All of this "cleaning" does not affect the bonding of the Thermark at all.

As I was experimenting to find the correct settings, all non-acceptable tests were quickly realized by the engraved markings being removed during the cleaning process.

My application involves lasering text and lines on a 12" x 16" x 1/16" clear anodized aluminum plate. I make a fast pass to mark the plate so I know where to put the tape, and then make the slower, working pass.

My application would probably be easier if I had a 40W+ machine, but I have settings that give me desired and repeatable results with a 30W machine.

I gues all of that didn't help you at all? Oh well..I'll post it instead of deleting...maybe there is something in there that might help. Good luck.

[Rodne Gold]

You need to modify settings to survive the scotch pad test - 20 hard rubs with a scotchpad should niot remove the marking or affect it at all.
Key to using this stuff is a scrupulously clean metal surface to start with and a clean with meths , thinners or benziene will degrease it.
Thereafter a thin even coat needs to be applied.
Overly thick applications wont work well.
Suggested starting points for settings are 100% power and the laser wattage as a % speed.
IE a 30 w laser would run at power 100 , speed 30. fine tune from there. "Overburning" will also be a problem, ie the adherence issues can get worse if you put in too much power.
Failing all that , a polyurethane coating might protect the item as would a laquer dip... however its not always possible to do this , for example a leatherman or a pen cant be dipped or coated without seepage of dip/laquer into working parts.
At the end of it all , In my experience , these coatings really only work real well with brushed finish stainless
Shiny materials and stuff like chrome coatings , aluminium, brass and copper might give far more variable results than SS.

[David Griffiths]

Steve
Agree with Rodne,
Metal has to be squeaky clean.
We had what we thought where plain stainless steel plates. However they had a light clear coating on them. Once we rubbed and rubbed and rubbed the coating off we had no further issues.

[Steve Chalmers]

I do 20 plus extrusion dies a month for one of my accounts, and have absolutely no issues with using the spray. The tape however was another issue entirely.

I have a 50 watt Universal and use the settings of 100% power, and 25% speed. The dies are 12 inches in diameter and are 2 1/2 inches thick. Because the steel is so thick, I found I had to run substantially slower to get the marking to stick, but nothing I tried worked consistently with the tape.

Steve

[Steve Rozwood]

Hello Steve,

First I have to hand it to Rodney and Dave I am a representative of the LMM-6000 CerMark product and I couldn’t have handled this question better myself. (I’d better watch my job!) We laser power grids on a sample piece of the same substrate that we are marking on to find the best most durable mark. A typical power grid for marking metal with a CO2 laser can be set up in a matrix or a graph from like this:

100 O 50
Power 100 O 40 -Speed
100 O 30
100 O 20
100 O 10
100 O 5

You can set up the power grid any way that you want, the "O's" represent a filled block. Your laser driver will have a color mapping option that you can set the power and speed settings according to the color selected. This way you can send over one job with different power/speed settings. When are done making the power grid then you should scrub the material, like Rodney said, to find the best color with the most durable mark. If you would like to contact me to for any personal assistance on power grids you can e-mail me or contact me by phone and I can give you more detailed information. I hope this helps and not confuses you.

Thanks,

Stephen Rozwood
Technical Service Representative
Ferro Corporation
251 West Wylie Ave.
Washington, PA 15301

Phone: (724) 223-5990
[FONT=Bookman Old Style][SIZE=3]Fax: (724) 228-3170