We do both rotary engraving and laser marking, but I have not had good luck marking black on a clear anodized piece of Al. I know that it can be done because I have had other vendors do it for me, but I don't know the complete process.
1) I was told that you have to do a chemical treatment to the top of the material to turn the marking black. I have seen mention of using Flow Master?
2) I have found a website describing the manipulation of power and speed to produce black marking instead of white. But I have not been able to make this solution work successfully.
http://www.synrad.com/search_apps/ap...riefs/13-2.htm
BTW I have an Epilog Summit - 25 watt laser.
Any input would be greatly appreciated.
More info found:
I have been looking around a bit more and came across:
http://thermark.com/web-content/Ther...apply_inks.htm
they advertise a couple of products that are spray on chemical treatments to produce black or colored (many colors avail.) marking with a laser. This product comes in a paste form (paint on), aerosol (spray on), and tape. I am having a hard time deciding between aerosol and paste. Does anyone have experience with these or similar products?