K40 Laser Cutter
|K40 Laser Cutter|
Michael went and bought a $600 K40 laser cutter and made it useful with some modifications. It now has a 3d printed air assist and cable chain fed by an airconditioner compressor, custom extraction with 6 server fans and a water tank with a pump feeding the laser. The laser runs CorelDraw X7 with the LaserDRW plugin installed. It can cut 3mm materials such as Ply, MDF and Acrylic. The laser can also engrave these materials. The bed size is A4 and eventually the internals of the laser will be liberated to a larger gantry and enclosure.
 What to expect when buying one
Not a lot. You get a cutting area about the size of a piece of A4 paper. The gantry isn't heigh adjustable either. Don't expect it to work out of the box. The software it comes with is rubbish as well. I recommend buying one to get the parts though. You can also do some basic cutting and engraving operations on it like front panels and small boxes.
The laser comes in a very large plywood box with plenty of foam padding for the important bits. You get the laser, a very poor extraction system, a small water pump and an A4 document holder with the manual, cable and some other misc stuff. The tube is well protected with plastic tubes filled with air. The belt on the X gantry in my laser was broken off, so I had to re attach that.
 Air assist and the air compressor
The air assist is a very cheaply put together system, with little regard paid to safety or strength. My unit has the following items in it:
- Refrigeration compressor - $0 and found in a broken air conditioner
- Plastic bucket that the compressor sits in. Filled with demineralized water. Not OHSA or children friendly - $1
- 3D printed air assist nozzle - http://www.thingiverse.com/thing:72691
- 3D printed cable chain - http://www.thingiverse.com/thing:34661
- Bunnings PVC hose. Diameter needs to match your compressor - $6
Yes, the compressor sits in a water bath. This passively keeps the compressor cool as it runs. If OHSA or common sense gets on your nerves, you can wind some PVC pipe around the compressor and feed the winding with an aquarium pump. You could also run an oil bath, although getting oil that is odourless and doesn't expire is difficult. This system works fine, and with a long enough PVC pipe, doesn't send oily air to the laser. While it may be tempting not to use cable chain to feed the hose to the laser, if you don't run it you run the risk of the laser beam hitting a hose and cutting it.
The extraction is equally cheap and nasty, comprising of materials found lying around at home. I have quite a bit laying around, so you may have to do a bit of running around.
- 6x Delta 12v high speed server fans. These can be picked up from Aspitech for a dollar each - $6
- 12v 100amp server PSU. A bit overkill for this application. Also an Aspitech purchase - $10
- 3mm plywood. Can be purchased as a sheet from Bunnings - $11
- M4 hardware to hold the fans together. Stolen from Troy's stuff - $4 worth
I basically just doubled up the fans with the M4 screws and put them side by side in a row of three. Then cut the plywood with a knife and snapped along the score marks until the pieces were the right size. You can get the idea from the photos - I did this in about an hour after work with no plans or dimensions. Sorry for the lack of plans - I may end up making a laser-cut file eventually. My build reuses the original air hose supplied to save cost. This is just vented outside.
The fans are extremely loud
Search "laser cutter" on eBay to find the laser. Get the ones that are in Australia.
Light object - http://www.lightobject.com/ - Good for some bits, especially the DSP upgrade and the CNC Air Assist nozzle.