Does anyone have an idea how to stop this

In the attached picture you can see that the material is scortched. The mateial came masked with a fairly thick clear masking. I am using a 40W chinese laser. This scortching only occurs on the top side of the material. It also only occurs where there was an air bubble in the masking and I had to reseat it. Would it behoove me to speed up my cut speed a bit (currently 10mm/s) and run multiple passes? I think this would keep the heat in 1 place less time but don’t know if it will help. Just asking and not testing because I have very little excess material for the project and I blew most of it on this.prototype.

You don’t state what the material is or the thickness. Either way for clean quality cuts you need adequate air assist.

Appologize for that…its 3mm mdf core and my laser indeed has air assist…whay is a proper psi? For this cut I was around 15.

With air assist it can be a bit subjective because the pressure is one thing but the size of the opening in the nozzle will play a big part due to the pressure drop at that point. On my set up I would probably use 25psi, my nozzle opening is 4mm dia.

My first impression is that the masking of the product is amplifying the problem. I actually believe that the masking is melting a bit and then trapping that heat under it causing the material laminated on top of the mdf to also melt a little.

Maybe you could run the same job on some 3mm mdf that doesn’t have the masking and compare the result. If it cuts nice and cleanly the you’ll have your answer.

I cut acrylic that has a coating on both sides… I peel off the coating from the laser side and leave it on the bottom.

It’s also advantageous to engrave from the intake air side and move towards the exhaust. The keeps the vapor/smoke off the newly engraved area. When cutting, you usually don’t have that option, but use it if available.

My personal experience with a 50 watt is the higher the pressure the better when cutting mdf.


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Thanks Jack…was my next plan…was going to go bare on the top because its a lot more probable to get the soot off than fix the melted covering