Depth burn without soot?

[mattm58]

I'm new to laser engraving, so forgive me if this is a stupid question:

How do you engrave with depth, but without the soot/ash?  Take for example this image:

http://woodengravingservices.com/images/home-images/01-02.png

There is depth to the engraving, but it's not black.  I've got a 2.5w a3 laser and using T2 software.  If I engrave fast or with low power where it's only the darker brown color and not black, there's no depth.  If I engrave slower then the engraved part is black.  Do you have to have air assist constantly blowing the piece where the laser is actively burning?  Do you do low power and multiple passes?

Thanks for taking the time to read through and helping out a newb!

[Zax]

Some materials work better than others, but air assist is important for a deeper burn. Multiple passes at lower power often helps too.

[Administrator]

>How do you engrave with depth, but without the soot/ash?

I don't see how you can without getting soot and ash. To burn to a depth means you're really burning with the laser so there is going to be soot and ash. You'll need an air assist blowing right onto where your laser beam hits your material.

Attachments

Air1 shows my setup on my laser machine.

Air2 shows my 60Litres/Min air compressor. This is a bit too strong and I've had to choke off the air hose valve to reduce the air pressure blowing onto my wood. You do not need a lot of air flow, just enough to gently blow away the soot/ash. If you have too much air pressure, it will blow the soot/ash onto and into the surface of the wood and look like a black smear. You'll have to experiment to find the right pressure. I'm guessing a 40 Lites/Min unit would have been about right.

Air3 shows my air manifold and note the valve I've turned to just the right spot to control just the right amount of air pressure coming out.

[ThothLoki]

I agree on the air assist. I use a normal air compressor with an independent regulator for my air assist. When cutting, I use 40psi.

[mattm58]

Thanks all!

Admin, where did you get the plastic adjustable connector in pic 2?  Looks like what I have on my scroll saw,  may have to "borrow" it from that tool for a while.   

[Administrator]

You mean pic 1? I bought it on Amazon.

[nottingham82]

The ash isn't firmly attached when you burn slow. Use air assist and then use a bristle brush to bush off the ash. It will leave soot all over.  Use a rag and alcohol to wipe it clean. I usually engrave at 100mm/s or slower

[av8r1]

Could have also been done with a CO2 laser; they tend to cut deeper and leave behind less char.