CO2 Laser Cutter

Hello everyone! Today I want to show you latest upgrades I made to my CNC laser cutter. You can also watch a video, content almost identical, but my English is bad. Also you could be interest how it all begins so the first part is here.

At the moment, the machine has the following parameters: a working area of 800 by 660mm, a laser with a power of 40W, rail guides, Freon cooling made of a used air conditioner. I have been working on it with some modifications for several years, mainly I make decorative lamps - you can look at them here. And so why did we have to redo something again?

The main problem in the machine, in my opinion, was the rigidity of the structure, of course it's about 3d printed parts. For the initial design just to play around, or for hobby this was enough, but when the task is production and, accordingly, earning money with the equipment, it's starting to be a panful experience. When trying to increase the speed, I realized that electronics might be able to handle it, but the mechanical parts are definitely not. Maybe mounts for mirrors, are fine, but strong parts like mounting the frame or axes, it was just not a very smart move to made it from plastic.

It was also stupid to place the laser tube on the wall of the machine and therefore it was not connected with the frame in any way, because of this we get a beam flight away during deformations of the wooden body.

Considering the above, I have done global work on the errors and there is little left of the old machine.

The frame, as last time, is made of a structural aluminum profile 20 by 40mm, we will need a little more aluminum than before.

The co2 tube is now located on the frame itself, in this regard, we get a monolithic structure that can be moved around as you want, installed in any housing and we will not lose rigidity.

Important areas where greater strength is needed were replaced with aluminum ones. I made them using a CNC router, but the parts are designed in such a way that they can even be made with hand tools, in fact there are no tricky fasteners here, basically they are just rectangles with holes for fasteners and a couple of corners, at first I thought to weld them, but I don't have welding for aluminum and I don't have any friends with it either, so I decided to just heat it up and bend it, it doesn't turned out super nice, but in fact even a couple of degrees angle won't play a big difference here and everything can be finalized with a file. I want to draw you attention to the author's belt tensioners made of 5mm stud and soldered nuts.

A sheet of 5mm aluminum about half a square meter in size cost me 10 dollars with delivery, it will be enough for 2-3 similar machines.

Where I could save money, I left 3d printed parts, this is the 1st mirror mount, the laser tube mount, the belt tensioner and some little things.

I replaced the belts from 6mm to 10, after all, they have a decent length, about a couple of meters, I decided that it would be more reliable this way.

The shaft for the Y-axis is HSS rod, the stud will also work, but it bends slightly, the price of HSS rod is 10 dollars, so I think it is a good deal.

The motor on the Y-axis was replaced by the Nema 23, the X-axis left the Nema 17, but I bought good ledshine motor instead noname Chinese one.

Let's go over to electronics, the brain of this whole design is a specialized controller trocen awc708s, now it seems to be no longer available, but its analogue AWC7813 will work the same, there is really no special difference here, there is no need for much power for this configuration, I do not have a lifting table, one laser, so - minimum equipment is needed only to work stably. Whether it's trosen or ruida, it doesn't matter.

About saving money and made a controller from arduino and GRBL firmware - I have passed this stage and my opinion is that if you need the machine for work and it will turn on at least a couple of times a week for a few hours - you need to buy a special controller. If you still choose arduino, be ready for lags, reboots in the middle of work, skipping steps and all that, I told you.

Drivers for stepper motors - I use the DM542, this overkill for my machine, supports power up to 50V, current up to 4.2A, microsteping up to 1/128.

I also attached a homemade board with relays and an optocoupler, the air compressor will turn on from it when the machine starts working and the cooling when the temperature increases, you can replace it with a relay module like used with arduino.

Then everything as usual, the power supply for the controller, 24V for motors, 12V for air compressor - it can be excluded if you have a AC powered compressor and a high-voltage one for the laser tube. By the way, I haven't changed the co2 tube either, it still works at 40W, no more is required yet. I don't show the circuit because it will depend on your controller, and what additional things you use, but everything should be simple, the documentation should indicate where to connect. A minimum is power wiring, connection of drivers, motors and a laser power supply.

The cooling is old made of the air conditioner - everything still works fine - there is a separate video about it, the only thing I have slightly modified it and added a second loop so that the liquid inside the tube circulates in a closed loop without contact with the external environment. The air compressor is for septic tanks, I don't cut plywood often, so it's quite enough.

I don't really see the point to show exactly step by step how I assemble it, firstly, the design is essentially primitive, secondly, there will be only few people who repeat it exactly, and you can figure out everything just by looking at 3d models, I tried to indicate everything there to the single bolt. Regarding the 3d model, there are plans for aluminum parts, for the CNC router, all the details are drawn, a file for the fusion 360 program, you can download the models by subscription, it costs 5 US dollars, I decided that if a person decided to make a machine for almost a thousand bucks, then he will find few dollars for 3d models.

Let's talk about the money, I made this google sheet where I tried to write all the parts I used, as well as their cost and links where I purchased. As you can see, the total cost of the components came out about 900 dollars, while the machine body that can be made from anything is not taken into sheet, I have MDF walls and a table made of a steel pipes, I think it costs me about 50 dollars. As well as cooling in my case, a used air conditioner 50 dollars. The most important thing is that my time for development and assembly is not taken into account. If you have all parts on hand, the assembly will take about a day or two.

How much does cost the analog of similar CNC machine? let's see, since there is no cnc with exactly the same working area as mine, I take into account the nearest similar 900 to 600mm. And so the average cost of such a machine is 5000 us dollars, I make a discount on the fact that the laser tube is usually more powerful then I use, and the working area is slightly larger, but there is no cooling, so if you a purchase CW5000 chiller, this is a plus of about 1 thousand.

Savings with self-assembly comes out about 2-3 thousands. Naturally, everyone decides for themself, you have to keep in mind a lots of factors, time of delivery, the Chinese can mess up something for delivery, you could receive wrong parts, assembly time, if you are not good at electronics, you can get confused, if you break something in the process u have buy new part. With preassembled CNC from manufacturer, you have a warranty, agreed delivery times, as well as technical support. If peaple asking me for advice in this case, I usually asking for purpose of having CNC laser, if it's only a hobby and just another interesting tool to improve your workshop it's OK to try to building it by yourself, but if we talking about a running a business I would probably recommend to buy a preassembled CNC, you will make more money then you save in the time you waiting and assembling your own.

I originally wanted to add to this video what can be done with such a laser and what is impossible, some examples. But I thought it would be better to leave the purely technical part here. I hope this video helped someone, maybe even motivated. That's it for now, good luck - bye.