Mini CNC laser etcher

lucky said:

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!

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That would be good. Id like a machine that could do that. Engrave images

I was thinking of making one with a 5W IR diode. A friend was gonna make an A3 size table with the motor and controller installed for around $350, then I realized I won't need it. Now this got me thinking about a laser cutter/engraver again. Is it possible to making the cutting area larger? like half of A4 paper with a budget of around $80-100?

Hey check out the shapeoko stuff. You can get just the makerslide and end plates for maybe 100 and the standard size is about the size of a sheet of paper. Extra wide.
I was considering getting a fiber coupled array and running the end with a few optics down next to my spindle and having the diodes away from the stepper, and spindle vibrations.

Elyas, look at getting some old flatbed scanners. You can use 2 of them in basically the same way as the CD drives and get a larger work area. Alternatively you can look out for some plotters on eBay and the like. Usually they are designed to carry pens, but you can easily stick a module in or even fiber couple a larger diode.

Things said:

Elyas, look at getting some old flatbed scanners. You can use 2 of them in basically the same way as the CD drives and get a larger work area. Alternatively you can look out for some plotters on eBay and the like. Usually they are designed to carry pens, but you can easily stick a module in or even fiber couple a larger diode.

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scanners! i never thought of it hehe what brand has the squar type motor?

This is pretty awesome!

I'm trying to build a similar setup using Arduino and EasyDrivers for controlling stepper motors.

I am planning to use two lower powered DVD burner lasers and combine them in a PBS cube for double the power. My budget is very low for this so here is my list so far :

Two Combo Drives from MacBook laptops for the XY platform
2 adjustable current Drivers from Aixiz - $5
2 lasers from DVD burners - i don't have any specs for them
1 PBS cube from one of the drives that i took apart long time ago
1 Arduino Uno
2 Easy Driver drivers for the stepper motors from a Chinese ebay seller - $16

Will update on the project as I go.

Keep us posted.

If its any help, I have some SLA 7xxx series microstepper chips as featured in EPE.
These are fairly easy to use and the bare board is still available.

I also have a few nice motors, optics and other bits, PM me the specs you need.

Some folks find that using a Bluray burner diode gives more precise cutting, but is more expensive for the same power level..
Obviously using safety goggles is a must, might also be worth having a sensor ON the goggles that shuts everything off if any reflections are going where they shouldn't.

I did attempt this with flatbed scanners but my first attempt cooked the stepper motor- they really aren't designed to carry much weight.

-A

I've also started to build one last week. However I made sure to build a solid platform.
I got the inspiration from the Instructables "bioprinter".

I've made a pair of blog posts in french, and I still have to translate them in english.

Here is a picture:



Working on the firmware for a PIC18F4685 now, I have a g-code interpreter ok. I will do stepper control via L293s. G0 is ok, I still have a little work to do on G1 to manage feedrate and simultaneous movement.

Software will use Inkscape -> Gcodetools plugin -> Universal G-code sender

I'll use this 200mW red laser I described elsewhere. However NO MORE POWER BEAMS until my googles are there (sigh, that's long).

How many mW of 405nm would you suggest to start burning things? 200 mW or less?

The motors have a 10-ohm winding and are specified at 5V, see here: http://robocup.idi.ntnu.no/wiki/images/c/c6/PL15S020.pdf

They have 20 steps/revolution and the lead screw pitch is 3mm, so that 0,15mm of resolution in full step mode and 0,075mm in half-step mode. I still have to test microstepping, I found a nice controller but this will require a PCB, so that's for later. However some people at Instructables reported that microstepping didn't work with this motor model.

Best regards

PS is this worth a new topic?

For microstepping (up to 1/16step) and ease of control (stepper advances 1 step each rising edge of a simple clock pulse), i would recommend A3983. It is a const. current driver (unlike L293), meaning you can actually adjust the peak current in the motor and find the best compromise between run time, torque and motor heating.
A4982 is similar in operation, but it also features output short circuit protection. The H brdiges are latched off during short, while A3983 and A3984 explode.

I was looking at the TI DRV88xx series.

Yesterday I got the algorithm for the G1 command working
Steppers will move this evening

why not?...but do they have Vref inputs for setting Itrip? if not, you would have to experiment with series and parallel combinations of shunt resistors

I think they do, have a look:

http://www.ti.com/lit/ds/symlink/drv8825.pdf

Well, IIUC, microstepping requires current control, so yeah, they shall have a way to control current

However this evening I'll be using an L293 on a veroboard

o yes. that one is not too dissimilar from allegro chips in terms of driving.
i think i have the gerbers of a small pcb with A3983 on it along with just the basic components needed for operation, i can share that if you like

Driving is really straightforward, it's just a matter of step/direction TTL inputs

Thanks for the proposal, but I'll decline it, because I have too many projects, and I'm struggling to finish this one without being too distracted

I will do that later if I find this project useful, because I don't think a 75um resolution is good enough, and I don't like the fact that 1mm = 13.3333... steps

So I'll have to build microsteppers at a moment, but... not now I'm forcing myself to finish the first step : axis control. I'm quite close, and impatient to leave my day job to have a try Then I'll have to actually draw something with my laser, and after that, I'll think about better mechanics, stepper motors and such.

BTW I just received my cheapo laser googles from ebay \o/
they look wonderful, but I have to use them with care, because I have no idea of their efficiency I can only say that I can't see red LEDs glowing through them, but that's far from enough

ok, good luck with your endeavour.

hi Lucky,

do you use cnc tb6560 driver board?
i am searching in ebay, the closest price to $45 price is chinese tb6560 3 axis board with paraller port with mach3 software. Thanks you for your answer...

i am gonna build with, and already contacting dtr-lpf to buy one of these 405nm laser