Engraving on metal help

[mike klein]

I had a customer send us some metal they wanted laser engraved. I am told the material is a zinc alloy metal. After coating the material with
cermark and engaving it, the engraving wased right off. Possibly this material has some sort of coating which must be removed first??? Has anyone else came accross this type of material..Mike

[Joe Pelonio]

If you used enough power and went slow enough and it still washed off
then chances are it had a coating, though I have not tried that type of metal. Try cleaning with denatured alcohol, run a small sample on back (hate to waste that cermark). Otherwise what I do on coated metal is tape it down, run it without the cermark, then without moving it spray and run again. The first run burns off the coating so the cermark will stick.

[Kevin Huffman]

Hey Mike,
What wattage of laser are you using? If it is a 12w'er it isnt powerful enough to do what you are asking. You have to have at least 25w or higher.
We normally run our machines at 15% speed and 100% power. That is a 25w machine that runs at 42ips. If your machine is faster you are going to have to slow it down alot more. I have had some metal samples where I have had to take the speed all the way down to 3% speed to get it to stick.

Also try Joe's suggestion, engrave the area first (to possibly remove the coating) then try using the cermark.

[Michael McDuffie]

I have to run polished aluminum and brass at 25% speed 100% power on my 70W machine to get consistant results. Especially if the customer has not done an extra good job of cleaning after polishing.

Michael

[mike klein]

These items are metal pet jewlery. One side is bare metal, the other looks as though it has a clear plastic coating on it with a design underneath it. I run a 40w machine here, and did get it to finally work by turning the speed down to 10% with power at 80%. It's a strange item as when I went to take it out of the template I rigged up, the plastic coated side was hotter than a pistol, but if I try to increase the speed or decrease the power the cermark won't stick. At the setting I mentioned earlier, it turned out perfect. I think what I may have todo is not engrave the entire tag and just portions of it to let the heat disapate between engravings. Not sure what is sandwiched between the 2 surfaces, but something in there retains the heat..