Essentials for cutting with a cheap chinese laser cutter (old).
If you want to have a laser cutter in your workshop and have only some $500, enter eBay and look for chineese, 30x20 cm, CO2 laser machines. Specify voltage when making purchase and you will receive some time later a box with a laser machine and some extras for it to work.
What you will get
Make space in a table and connect the hose (included, cut it in half) in the laser tube found inside the back of machine for water to cool the tube
at all times, the machine has marks showing where water enters laser and where it leaves. A pump (included) has to be submerged in a clear water
tank (not included) to pump a flow of water inside the laser tube, so one hose goes from pump and the other to water tank to recycle water, Install the fume extractor (included) at the back. Connect all to a power line and a computer to the USB entrance of machine using included cable. You can now turn on everything. Wear special glasses (not included) for safety.
The control has a "test" button you can press to confirm there is a laser beam. The knob (keys in new) is a potentiometer so it has to be somewhere in the middle
for laser to produce a hole in a piece of paper placed under the laser head. If there is no hole then you have to orient mirrors for laser to
bounce into the head and lens. White tape (included) is for you to put a piece of it in beam entrance so to burn it until you get mirrors aligned.
BE CAREFULL! the laser beam is not visible and you can make a hole in your hand instead of tape, it´s like a super hot needle that gets into your
Clean mirrors and lens once in a while using cotton and alcohol, never leave a finger mark.
You will receive a CD with Moshidraw software (LaserDRW new), instal english version into your computer.
I personaly had lots of problems trying to cut files imported in Moshidraw so here is what I do for success: For drawing I use Inkscape, it is great for making gears. I convert objects to paths and save a file in DXF format (make sure you select "mm"). To check I open the file in LibreCAD, another great free software. If something is not visible you will have to convert it to paths back in InkScape. Sometimes you will find that there are lines that you did not draw. Open the DXF file in Inkscape and delete all the extra lines. Save again in DXF, that´s it!
Import the file in Moshidraw and maybe you will not see it. Select the drawing in the layers box and open the cutting/engraving window. If you turned machine on you will be able to move the head in X and Y axis by entering mm values.
Asign a cutting speed and select cutting, you will have to experiment turning the knob (best not to use it at full) and asigning different speeds
to achieve what you want. It is good thing to start with a 10 mm circle and writing results to make a chart.
- Remove the alluminium plate that is inside machine.
- Cut the metal fume extractor tunel using a powertool, in advance cover everyting with cloths to protect from metal dust and later check for loose screws all over the place. Make a wooden platform with different wood blocks so working material is 50 mm from lens.
- Use some metal plates sold at Home Depot that are for joining wood, they have many spikes so material is not in direct contact with platform. You will now be able to cut as big as the machine can.
- The fumes are bad for lens so it is advisable to add air flow from a compressor via a rubber tube close to were the beam hits material, that way the fumes will divert and also it will prevent fire. There are funnels for download at Thingiverse for 3D printing that fit in the laser head so to insert the hose comfortably and concentrate air over surface.
- Use ice to cool water and a termometer to check laser tube water temperature. Do not let water go higher than 35 Celsius. I found in trash a working water dispensing machine that was old and rusty but it is great to cool water. Place hose along the freon tube spiral that surrounds container.
- Buy spare CO2 laser lenses at eBay, 50 mm and 100 mm. The 100 mm lens makes a slim "X" trajectory for a penetrating beam. They don´t last as much as the laser tube (11,000 hours they claim).
I know... seems like I was hibernating for years, new ones are here and should be less fuzzy. Enjoy!