Multi pass cutting

[sykic]

Can anyone expain what is wrong if anything with using a laser to cut through wood by repeatably cutting if your laser is not powerful enough for a given thickness of wood for your power of laser.?

ie do a two or three pass cut

Can you reduce the burning effect by moving the laser faster not cutting as deep but cutting twice/three times?


Not well worded hope it makes sense

Sykic

[MacGyver]

As the laser needs to be focused on the "lower" layers, the beam will be partially occluded by the "upper" layers, preventing enough energy getting through to cut the "lower" layer. This can be mitigated by using a longer focal length lens.

[MonoNeuron]

Yes it is possible. Other forum members do this all the time because of low power but they use air assist to blow away the carbon buildup.
Personally I would focus at the top of the job and raise the table the thickness that the laser cuts through (about 3mm for my 30 watt at 0.15 ips) after each pass but you will still get a fair amount of carbon charring on the cut.

[lamicron]

There are a few problems when you cut in several passes, in acrylic the cut get some deviation, in wood depends the hardness of the wood, if too hard you couldnt cut, some like aglomerated plates cant cut. Plywood cuts very well.Cover the surface with a wet paper, it works fine
Cutting acrylic with the protector plastic film avoids the stain produced from the vapours, maybe that way you can avoid it with the wood.