Greetings, I'm having problems engraving the little gold perpetual shields you sometime see on honour boards or perpetual trophies. The problem I am experiencing is that no matter the settings I use (Power, Speed, DPI etc), it fails to engrave the perpetual plates. If anything, it leaves a faint ghost-like impression on the surface of the perpetual instead of bringing out the white colour it should be from engraving.
My machine is a Chinese 80w laser engraver, and it works fine on anodized aluminium (black coating), laminated plastics, acrylics, wood, and glass. But these little perpetual shields are not engraving like they are supposed to. I used to do a million of these plates on a weaker Trotec machine, so I don't know what is happening. These plates used to be happy engraving with the same settings as laminated plastic, but this is not the case with the new Chinese laser engraver.
For anything who doesn't know, the perpetual shields are aluminium with a shiny coating in either gold or silver, and are supplied from trophy component wholesalers. They are specifically meant to be laser engraved.
Any wisdom about this would be greatly appreciated.