What am I doing wrong? Trying to cut 1/4" MDF

I have a Gweike laser about 7 or 8 yeras old. It is an 80 watt RECI tube. It has probably sat unused for 90 percent of the time. I usually cut 1/8" mdf and some plywood. Before I switched out my contoller to a Rudia I was able to cut 1/4" MDF easily. This is the first ime I tried the 1/4" since I swapped controller. I have to run it at 10 speed and 95% power. At these power and speed it really charrs the edges. I have cleaned the mirrors and lens. I have tried multiple passes, no air or full air everything has the same results. Can anyone think of a setting I can change?


If the tube is 7 to 8 years old, its possible the tube is end-of-life. The shelf life on a laser tube unused is hit or miss, but the shelf life on a rarely used laser tube is less. I recall seeing documentation from Reci indicating long periods of idle of a previously worked tube was not recommended for the longevity of the tube’s useful life.

Only way to know for sure is to test with a meter:

8 year old Reci tubes are still fine.

I installed a new/old stock 100W Reci in 2018, made in 2011, and its still working at good power today, in a commercial setting.

New Reci, EFR and SPT tubes are far better than ones from 2010 and before. They used to use gum arabic to seal the atmosphere in, which allowed the gas to slowly leach out over time. The design of tubes has changed a lot since then and they no longer lose gas.

Cheap tubes still do, though. They still use gum to seal them. That’s why Reci/EFR/SPT is nearly twice the price of cheap tubes. They’re better.

The most I’ve seen was a commercial cutter in Malaysia that had a 150W Reci with about 12,000 hours - most of it at 80%+ - before I changed it out. They were amazed at how much better it performed, but it was still cutting decent thickness of MDF and acrylic even with 12k hours on it.

There’s not much to change in the way of settings. It’s all about the PSU, mirrors and lens.
I’ve been cutting 9mm ply and 6mm MDF all day today on a 100W Reci - 28mm/s for ply and 26mm/s for MDF at 80%.

I can cut 3mm (1/8") at 55mm/sec @ 80%.

But, I have a 3" lens of good quality which cuts better than the same settings using a 2" lens.

I’m cutting 6mm Premium MDF with 80W EFR F2 at around 8mm/s to 10mm/s with a 2.5". Haven’t gotten the 4" mounted yet but hope to speed things up when I do.

I do know my power percentages changes when I went from a Top Wisdom to a Ruida, but only by about 3%.

Dave, when you cut the 6mm mdf what does the edges look like? is it a nice brown color? When I cut mine it was charred. when you handle it it get all over your hands. I don’t know what you would do to paint it. I am getting ready to buy a meter to see what my laser is putting out.

Eh, they are plenty dark, but I expect that cutting Premium MDF. They are not to the point I would call sooty, but I do occasionally get a bit of something on my fingers. I had a bad soot problem when I tried to cut 9mm with a 1.5" lens… that got ugly.

Was a LOT worse back when I tried the Home Depot version of MDF. The two are not even in the same neighborhood. Home Depot and the like sell ‘common’ MDF. When you break a corner it is almost as much a tear as break. When you break a corer of the Premium MDF, it has an audible snap. The resins are not as hard on your laser cutter either. I’m told the premium is also called double refined. I get mine from the local Weyerhauser distributor. Used to be Plum Creek, but Weyerhauser bought them out a few years ago.

Going to try a few Baltic Birch projects not to far down the road.

Definitely get a meter of some sort. Some guys like the mechanical calorimeters, I like the Dohicky and a K type thermocouple. Mainly for the digital accuracy, but also because it was significantly less expensive.

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