Humble Pie

[Dave Vigness]

Hey guys. I have been a stern believer in using the large diaphragm compressor my 80W came with, and have not had any real difficulties in doing my MDF cutting and engraving. They weren't perfect cuts, but I wasn't expecting that from my China Red.

After seeing a video clip a guy posted, and subsequent trials on my machine, I have to admit the benefits of higher air pressure / flow. I'm still playing with the pressure that works best for my Premium MDF, but I am getting MUCH cleaner cuts. I tried his initial recommendations of 40psi, but that's a bit much for my 3mm MDF. It does seem to work fairly well for the 9mm MDF.

The full 40psi does wreak havoc with my exhaust, so I may tame it down for that reason alone. Time will tell.

[Ian Bell]

Interested to know a bit more, i've been using my stock air pump with my "china red" laser since I bought it. Lately my mdf cutting has been poor with same settings but i've put that down to the tube nearing EOL. Edges are charred and having to do multiple cuts. (Currently sourcing new tube - looking at mcw laser)

I'm sure there's more technicality behind the air flow, perhaps it's time I took another look at russ video on air assist videos

[Dave Vigness]

I've followed Russ' videos pretty closely, but I also have to realize that he's doing photo engraving, card stock, and acrylic.

I'm not getting any faster cutting so far, but cleaner... OH YEAH! I cut 99.9% Premium MDF. I used to get the edge of cut 'grunge' on everything. But with high pressure, they come out almost like it had been cut with a router. Now I'm talking surface, the edges are still laser cut char, but CLEAN top and bottom. My first guess is that the high air flow is taking the resins away before they have a chance to settle.

Will play more in the next few weeks, real life has me busy the next couple of weeks, but I will update as I know more.

[Doug Fisher]

>>The full 40psi does wreak havoc with my exhaust<<

Dave, can you please explain this more completely? Thanks!

[Dave Vigness]

I'll try.

Before the high pressure air, using the diaphragm compressor sullied with my laser, when I cut my MDF I get a fair amount of what looks like smoke smudges around my cuts. It's resin vapor condensing, but that is what it looks like. Not bad, but noticeable. If you take a look at my sample pics at the bottom of my google page, you can see it clearly on the Marine Corp coin. https://drive.google.com/drive/folders/ ... sp=sharing

Now my initial tests were just some circles on some scrap, but there was absolutely NO smudges of any kind. If it wasn't for the laser char on the actual cut edges, you would have sworn the test circles were cut on a CNC and not a laser.

I have a lot more testing to do in the coming weeks to see how it performs on 3mm, 6mm, and 9mm Premium MDF, but I am expecting good results if my initial quick test are any indication.

The label on the factory pump says 70L/min if that tells you anything.

[Pete Cyr]

70l/min=2.47 cfm
I don’t use the aquarium pump that came with my system...I supply air from my shop air system. I did install a separate regulator and desiccant tower for the laser air.
I cut and scan at 15 psi. I scan lacquered cherry so any resin from scanning wipes off with a bit of windex on a soft cloth.
I cut mostly lacquered cherry 1/4 - 3/16 thick at 12mm/sec @ 55watts.
My process is not for everyone but when cutting I would recommend at least 8-10 psi when cutting ....this clears the debris and smoke from the cutpath and air flow enhances the combustion of the laser when cutting. Any smoke, resin, debris in the way of the laser beam will reduce the quality And depth of cuts because the laser energy is Being diffused.