this shows the engraving on the back plastic cover of a white 3G iphone.
it is engraved with a flatbed fiberlaser, called FP100, 10W from troteclaser.

the key is to have the right settings and to be in focus with the laser.
the result is an awesome image, which is permanent on the plastic.
in comparison to any printing, which would get off after a while, the laser marking is permanent.