This might help
Iāve been reading through this thread and then doing some practice on an old Macbook. Iām testing on the battery cover for a very old Macbook Pro. I found that if the focus height is set to .5" instead of the actual height of the material, .2", the etching comes out better, darker. Any ideas as to why? The settings Iām using are 300/Full/340 LPI.
Moving this thread over to Beyond the Manual since itās stuffed full of non-PG settings.
I donāt have an answer to your question, since I canāt imagine why defocusing would make the engrave darker, but maybe someone else will come along who has an idea!
Because youāre spreading the beam wider which gives you the same effect as higher LPIs which on anodized coatings ablate more of the coating or dye. On some materials like wood, a defocused image is usually lighter because less power is applied to any given point on the material. On aluminum, thereās no real difference between enough power to mark and multiples of that power in terms of the effect. You are getting less power with the defocused setting but itās still well over the minimum needed to ablate the coloring.
The advantage of defocus over increased LPI is speed - your defocused 340 LPI is much faster than say a focused 1350 LPI at the same speed & power as itās making 1/4 of the passes.
aWhen engraving MacBook, the Apple logo is polished, so the laser is reflected and it does not get engraved.
Welcome to the forum!
Careful with that. Weāve already had one person who accidently ran the engrave over the logo and it heated up so badly it burnt her screen. If it were totally reflective it wouldnāt have passed the heat through.
You are 100% right that it doesnāt engrave well!
Itās my understanding that certain MacBooks (the Air, perhaps?) donāt have the plastic logo in the lid, but rather a non-anodized section for it - so the whole lid is metal.
The laser can not mark metal. What happens when engraving anodization is the dye that has been absorbed into the surface, a form of oxidation, is evaporated. So any un-anodized section would be untouched.