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FrozenGate by Avery

Mini CNC laser etcher

Hey I have a shapeoko, for those that have arduino uno, they make a grbl shield for controlling stepper motors, which is what im using. Has x y and z drivers built in and adjustable current. Runs off of...universal gcode sender. Which supports tons of cad software.

Anyways, the grblshield might be cheaper if you have an arduino
 





This is amazing. How does the software know how much to turn the motors to get the laser and bottom board in the right place? Is it simple or a pain in the @%#?
Great work :)
 
Sometimes there's feedback, or it just knows from the number of steps made on the stepper motor (which the CDROM drive motors are). Many CNC machines use stepper motors.
 
Yes, most machines just rely on the motors moving an exact amount per each step, so the controller just tells it how many times to step. This meas if you jam it up, or try run it too fast, it'll lose its positioning and you'll have to reset it
 
flare09 said:
Hey I have a shapeoko, for those that have arduino uno, they make a grbl shield for controlling stepper motors, which is what im using. Has x y and z drivers built in and adjustable current. Runs off of...universal gcode sender. Which supports tons of cad software.

Anyways, the grblshield might be cheaper if you have an arduino
Click to expand...

Ohh that's a good idea!

Might have to try this my self!

-Adrian
 
Things said:
The controllers alone are $60 ;)
Click to expand...

I went off this pricing he posted:

$140 700mw laser
$45 3 axis CNC controller
$15 power supply
$8 (2) CD roms
$4 laser driver circuit
Total: $212.00

and figured with $72 (cd drive, power supply, controller) + hardware + profit, my price was decent, but, if the kit was $150, I would probably still buy it. That would be around my limit though.
 
I could use diodes to step the voltage down but for now it hasn't really been an issue, I have two fans that are on the rig to cool the laser power supply and the laser diode so the steppers stay with an acceptable operating temp.

The setup of the steppers was pretty easy, you simply select which axis you want to calibrate, the controller then moves the stepper a certain number of steps, you measure the amount of movement and enter it in then the software automatically calibrates the amount of steps per inch. It's quite straight forward.

This version of Mach3 does support encoder feedback so if you have steppers with encoders (or added them later) you could feed that back in to dial the resolution in even tighter. For me being accurate to 0.001 inch is more than sufficient though so I didn't add them.

I haven't added the home switches either but you could if you want auto homing after each job. For me this is just a proof of concept for a larger machine that I have planned....

With that said any thoughts on larger lasers? CO2 perhaps?

Thanks guys, let me know if there's any other questions or if you would like more vids!
 
I'm building my own lucky, did you extract that aluminium pillars to upper axis from some electronic equipment? I'm trying to avoid to ask someone to make it to me because it's gonna be expensive...
 
You it burn different depths. Be programed to burn longer in places So it could have shadowing? Or is it just burn the same ?
 
You can speed the feed rate up or down to give more or less time of burn into the part of course but mach3 also has a laser plugin that will pulse the laser to do engraving, for instance a picture.

The plug in converts a JPG into black and white image then assigns a value to each pixel based on how dark it is. Then the laser is pulsed by that value for each pixel to create the image. You could also use this to control depth if an additional control was fitted to the optics to control focal depth as it cuts. I'll likely add that feature to the larger unit once it's built!
 
They typically use a process call "dithering", which works fairly well at varying the different shades.

As for a larger laser, I probably wouldn't bother with something that small. The CO2 laser beam itself is probably 1/4 the size of your axis movement range, then all the focusing optics etc would take up a lot of movement room too.

This is my machine here, it has a cutting space of 1200x900, but you can see how physicaly large a CO2 laser is along with its bounce optics. You can't just throw a CO2 laser into the little module mount you currently have :)

DSCF5364.jpg


One option though, if you really wanted to do it, would be to make the XY table move the cutting bed instead, then just permanently mount a bigger laser above it. You could do this with a CO2 laser, but it's kind of overkill if you ask me. A CO2 laser and it's PSU (40W) would run you about $400 anyway. For another $400 you could get one of the cheap China eBay machines and call it a day :)
 
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Granted but this rig is only to test the functionality, the larger 24" x 26" rig would be for a larger laser like C02 or similar.
 
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