Is a PC fan based air assist adequate for occasional K40 usage?

I currently use a 2017/2018 vintage K40 very occasionally, and I’m planning to use it to do a large set of cutting soon, as I translate parts of the Reprap Wilson 2 design into lasercut components in order to reduce dependence on my mate’s 3d printer for making one. I think it has an M2 board.

It seems a little sluggish when cutting 4mm birch (my usual material, considering poplar as it is easier to cut), which I’m blaming on poor alignment and soot on the lens. I see there’s the ‘proper’ air assists using a compressor, but installing that seems like a bit of a job, especially when the K40 will be stored again in a couple weeks. Is a PC fan based setup much worse than a compressor system?

it really depends on how you’re using your K40. I hope you do have a blower extraction unit attached to the back of the machine. Regarding air assist, for cutting it needs to have some decent speed to blow soot and flames out of the cut or better down through the cut. That’s why a compressor type of system is used but a small centrifugal fan might work in a pinch if well directed and attached to the laser head.

engraving is all on the surface of the material so a PC type fan can be used to blow the smoke to the back where the main extraction fan would pull the smoke/air out of the box. A bit of cross ventilation by cracking the door also helps.

Both of these also help keep the smoke off the mirrors which will get quite dirty quickly without a functional air assist setup.


I have the extractor hooked up, it is doing a bit to suck out the smoke, I’ll try a PC fan setup and report back on how it goes. The machine isn’t interlocked yet, so I’ll maybe crack the lid a wee fraction. Perhaps cutting vents in the front with fans would give a boost to performance also?

That can aid in the smoke extraction a bit but I was only mentioning air extraction in my attempts to differentiate it from air assist…


When I bought my second-hand K40 a few months back, it did come with a PC fan on the head, I did not try it opting to go straight for an aquarium air blower from day 1. All I can say, is that it very effective and has made the difference when cutting However, I did have vents cut into the front of the lid so I mounted 2 fans on the inside of the lid to draw air in over the bed. Coupled with my rear fan and a short hose run to my external wall means that I have no smoke problems which was not the case before I fitted them.


The major failure in most of these isn’t as much the ventilation setup, it’s the honeycomb bed that removes your control of air flow.

It in itself is inducive to routing whatever air is there to flow into the honeycomb without crossing the material and removing debris.

I changed mine out to a rolled steel plate, with holes for alignment jigs and leave the front hood up about an inch… Great airflow across the material…

Until you control how the air moves within the machine and across the material it’s a bandaid on a poor design.

Try laying a sheet of something over the bed, so it doesn’t flow into the honeycomb and check your airflow then… On mine the air is drafted out the back/center…

Any additions are probably better :wink:

If you can smell it, you’re breathing it…