[Pjkli]

Hey guys, new to the forum and I gotta tell you it's fantastic to see all this knowledge in one place.

I would like some info on building my own Laser Cutter/Engraver. Anything will help. I do have a solid understanding of how lasers work, how steppers work. I fall flat when it comes to the link between the drawing on the computer screen and translation of the drawing to the material. Also, an explanation or overview a cnc laser machine would be fantastic! Thanks guys, and let me know if I get on your nerves asking a million questions!

Pj

[Red Earth]

PJ,

WHen you say laser cutter/engraver..... do you mean a CO2 or yag.

The former will be much cheaper to build..... but will only cut plastics and woods, etc. It will not cut metal of any type.

A biased opinion, Corel Draw is great for drawing your art. The learning curve isn't that steep, it's not that expensive and it can read and save many files.

There is a start for ya!

Phil

[zax15uk]

Pj,

There are a few interface options, perhaps the most common for this type of system is the step/direction method. You connect a suitable driver board to the parallel port and use software like Mach3 or Emc to send it real time signals.

You could also use a Pic based solution, either developed yourself or one of the available options already out there.

It really depends on your budget and needs.

If you search for step/direction drivers, and look at mach3, emc and other software options you'll see what might work for you. emc is free but some would argue it's harder to setup and runs on a real time version of linux. I believe you can get a USB external pulse board for mach3 which improves it's real time operation - there are also DOS solutions like turbocnc that work quite well too.

Zax.

[Pjkli]

Thanks guys for the tips so far. So if I get Corel Draw, and then say Turbocnc, what happens? Do I draw something in Corel Draw, then import it to TurboCNC? Then TurboCNC operates the driver?

Also, What is a Yag Laser and why do I want one? I was thinking I would start out on paper and wood/acryllic but metal would be something I would be interested in. As far as my budget goes, this is only a hobby at first. So what ever I can scrap together and steal or build is what will be used on the first attempt. I want to get my confidence up before I dive into a big expensive setup.

Edit: What is a Pic solution?

[zax15uk]

Corel is cheap and works ok for designing, TurboCAD is better for more technical based drawings but that would depend on your requirements. I use both, but do most of my work in ArtCAM (more expensive and not a hobby solution). If you need to pick one software, Corel is definately the best choice.

With Emc or Mach3 you could import directly from Corel, but TurboCNC will require the use of a DXF to GCODE converter like Ace (which is free).

As far as lasers, you have 3 basic options... diode, Nd:YAG or CO2. A simple IR or near IR diode will be the cheapest and easiest solution but you'll be limited to engraving or light cutting in paper, card, thin wood and some dark plastics. Hobby sized Nd:YAG is for engraving or light metal cutting and has the highest cost. CO2 is the best bang for the buck and can engrave/cut most materials with the exception of metal - but it can mark them using an additive process (LMM).

A pic is a programmable micro controller, it takes the job of creating the pulse train for the steppers so the PC doesn't need to work in real time - something Windows isn't really great at. There are several solutions that use this technique.

Zax.

[Pjkli]

So the PIC is basically the stepper driver? Or does it act more as the PLC?

Also, How does one vary the power of the laser so that it can either cut or engrave? Is this a function of the laser driver and the instructions sent to it?
Thanks,
PJ

[zax15uk]

PJ,

PICs can be used as stepper drivers, but I was referring to a solution where the PIC essentiallly becomes the PLC.

You will find most hobby CNC software is designed to use the parallel port to create the pulses directly, this is the cheapest and easiest solution.

Laser power can be modulated in several ways, the most common is probably PWM. The laser driver board would accomplish this task, either from an analog input or directly from a pulse input - perhaps the spindle signal.

Zax.

[Pjkli]

Can the hobby cnc software creat the correct signal when using a driver? I would like to build my own drivers for the steppers to save cost and to gain a better understanding of how my machine works. I'm definatley not in a hurry to get this machine up and running.

[zax15uk]

Let me clarify in case my reply was misunderstood.

When I said 'hobby CNC software' I was referring to low cost software designed for the hobbiest like Mach3, TurboCNC, Mach3, KCam etc.

So - yes, this is exactly their purpose.

I would suggest you develop a good plan and know what your requirements are before you begin. Work area, cutting method, leadscrew or belt drive, steppers or servo etc.

Zax.

[Pjkli]

Sorry about the mis-understanding. I was under the impression you could use the parallel port of a computer with some software to drive the motors directly.

Also, Kcam is a hobby cnc software? The only info I could find was from a Kcam website that built and sold whole laser cutting/engraving machine.

[zax15uk]

Well the parallel port can be used to drive very small steppers directly (with the correct software), but doesn't have the power necessary for motors you'd need for CNC. That's where the external PSU and driver board comes in. The PC still does the processing and hard work, the driver board is more like an amplifier.

http://www.kellyware.com/kcam/ is Windows based step/direction software, similar to Mach3 (well more like the original Master5). I was never able to get it to work smoothly, the pulse train was just not 'clean' even on a relatively fast PC with minimal install. Mach3 seems to work well, although I prefer EMC http://www.linuxcnc.org/ and TurboCNC.

Zax.