Hi Cameron and Otrhers
Following the posts heer and in projects I thought I could offer some insight into the type of material (Wood) that people are selecting to engrave.
All wood (soft and hard) has growth rings and the size of thos growth rings vary with the growing seasons. Some growth rings are dense (slow growth) and some are larger(faster growth). The growth rings also vary in colour . To show the affect of growth rings on an engraving I performed the following test.
I selected basswood (available at “balsacentral.com” in Australia) because to th naked eye it is uniform in colour and show almost no grain.
It would be considered as being between soft and hard.
I set up a vector engraving pattern on my emblaser 1 to gauge the effects of various power settings.
I set the feed speed at 22 mm.sec (Allow the laser to effectly burn without skipping some parts but not overburn as in slower speeds)
The enclosed image shows the results of that test
Notice the banding starting to show from 4% power onwards. This banding is the result of burning two depths of growth rings. The more power and you would burn deeper and therefore expose further growth rings. As the power increases the effect is nullified by the burn being darker.
With basswood the growth rings are very close and so the surface looks very even and even in colour. Compare it to Radiata pine where growth rings are large and vary a lot in colour bass wood would be considered a good wood to image engraving. But as the test shows the closely packed growth rings can show up especially in low power settings.
So if attempting to engrave an greyscale or bitmap image in wood , you would always have variances in the overall image because of the growth rings in wood.
The conclusion I make is that whilst engraving an image in wood is novel idea the results cannot be expected to compete with a black and white image on paper.
Its not the hardware that is the problem but the nature of the material being engraved.
(I have assumed that the laser is well focussed and the height of it above the surface ensures a very fine kerf)
See the results