Your opinion at speed/power for cutting MDF?

Currently I am cutting 3mm MDF at 30% power, 20 mm/s, 3 passes.

I have made test at 40% power:
-10 mm/s 1 pass - brown border
-10 mm/s 2 passes - blackest border
-20 mm/s 2 passes - not as black as 10x2, but darker than 10x1

In this 3 scenarios, the cut is ok (almost identical). The burn (stain?) “outside” the hole is almost identical also. Just change the color of the burned internal border.

Should I stick to 30%, avoid as pest the 40% power? Better more speed?

Any thought will be greatly appreciated.

I don’t use MDF but your cutting speed seems high. For 3mm ply I cut it in a single pass at 10mm/s and about 8mA power.

If you haven’t already, you need to at least temporarily hook up a multimeter to the laser and establish your max power relative the %power digital setting. it’s recommended not to exceed ~ 16mA on the tube for the best life time on the tube. You can’t assume 100% is 16mA as most people with digital controls find that 16mA occurs at a much lower (i.e. 50%) %power setting.

The stain you see with cutting and engraving is typical and mostly unavoidable with settings. The only way to avoid it is to use masking or sand off the staining. I always use vinyl lettering transfer tape masking which you can get in a bunch of different widths (I use a 8.5" width) .


Does your application could be done with other wood type ?

MDF is hard and full of additives which increase charing.

Solution is as Ned say, masking !


I have very positive experiences with MDF and HDF. If it is an ok quality I use the same parameter which also applies to plywood in the same thickness, + approx. 10%.
For 3mm MDF, my parameters are approx. 750 mm / min at 8-10 mA (approx. 35% in LightBurn) For 4mm the power settings are the same but speed is only 650 mm / min. (of course everything only with a single pass)
Without an ammeter you should not work with a CO2 laser, wrong settings will sooner or later ruin your tube.
I have a well-functioning exhaust and am not worried about the remnants of toxic fumes. The surface the laser leaves behind is actually “closed” in a nice way. I like to finish my items with bivogs, it looks great.

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I will borrow a multimeter and write down the amps in every 10%. Where should I measure? With laser firing?

The cathode side of the tube goes to the L- pin on the laser power supply (LPS). Measure the current by hooking the meter in series between the cathode wire and the L- pin. That is, remove the L- wire from LPS and hook one lead of the meter to the wire and the other lead to the L- pin.

Set the % power and hold down the test fire button with the laser on. Record the current.

Let me know if you have any questions.