Comments on: DIY plotter with laser

By: svofski

svofski — Mon, 14 Dec 2009 13:27:24 +0000

3-5cm should be fine, you can adjust focus back and forth.

By: jcox1968

jcox1968 — Mon, 14 Dec 2009 13:08:02 +0000

Any idea how high above the surface the laser can be to do this?

By: svofski

svofski — Mon, 14 Dec 2009 12:53:52 +0000

It’s going at 1cm/minute on slightly darkish wood, I guess. I never measured and I have it packed away for now, to provide space for other stuff. Those lasers can be found on ebay for whereabouts of $40 with shipping, you can buy one just to experiment: for the geeky type it’s one of the best ways to spend $40 imho :) Practical side of this is dubious, unless you do some decor/handcrafts stuff, like adding ornaments to kitchen boards.

By: jcox1968

jcox1968 — Mon, 14 Dec 2009 12:46:37 +0000

I am really curious as to how fast the machine in the video on this page was able to move(like, how many inches per minute…

By: svofski

svofski — Mon, 14 Dec 2009 12:42:27 +0000

@jcox1968: of course, why not. Provided that the surface is flat, you can do this with several beams. But aligning the optics may become tricky, methinks.

By: jcox1968

jcox1968 — Mon, 14 Dec 2009 12:32:02 +0000

Probably a really stupid thought but I must admit ignorance here. As for the wood burning, would it be possible to have say~~~ two laser diodes(such as from a dvd writer) both aimed in the same spot on the wood and be able to move a bit faster? (obviously this is assumed that the entire surface to be burned would be flat and level)?????
I have a cnc machine and would really really like to be able to burn designs in wood like this but I don’t know much about lasers.

By: barbiegirl

barbiegirl — Thu, 29 Oct 2009 17:19:45 +0000

I love it! Thank you, svofski, you inspire me! Yes, your plotter is THAT good! :)

I have already collected parts for over two years so I have a lot of belts and motors, but I don’t have any tool to make it GOOD, so I had to begin at the other end: Proxxon MF70. :)

This is a great framework to drill PCB, and I’ll make a similar one but in metal to get higher accurancy.

A CNC machine have 4 important aspect:
accurancy
resolution
repetability
speed

High accurance is useless with leadscrews who backlash a lot. The cheap one usually do that. Belts are much better than cheap leadscrews, but the torque/force will be lower. Get a bigger motor, The resolution increases if one use gearing to get more power but it’ll be slower.
(use belts to avoid backlash)

Don’t underestimate the powers of belts, they’re really great! :)

Improve accurancy:
Are the workplace REALLY flat? 1mm? 0.1mm? 0.05mm?
Is the gantry stiff enought?
stiff = heavy. heavy = bigger motors.
How’s the repetability?

Improve resolution:
Higher step/degree at the motors.
gearing. use belts.
leadscrews. preferably with zero backlash.
(or cheap treaded with bolts/nuts, but the accurancy will go down compared to belts)
Or belts with microstepping/1.8 degrees motors
lower frictions at the bearings (?)
Smaller and slower is a cheap way.

By: McNoob

McNoob — Wed, 28 Oct 2009 02:23:10 +0000

oh and maybe remove the pics of the flower tattoo might be wise.

By: McNoob

McNoob — Wed, 28 Oct 2009 02:20:09 +0000

having seen the hacked up thin film plastic he burned, I don’t think making solder stencils is going to work.

perhaps making them with some of the above ideas for burning off resist, and etching a stencil.

or a higher power laser to burn through faster before the adjacent plastic can warp and bubble due to heat transfer.

By: svofski

svofski — Tue, 27 Oct 2009 11:40:05 +0000

@Gibbon: did you see the HP-GL reference? There are commands that define speed and acceleration. I never had a real plotter so I can’t be sure if you can make it slow enough for a 300mW laser, though.

By: Funky Gibbon

Funky Gibbon — Mon, 26 Oct 2009 20:30:06 +0000

ive been trying to do the same with my Roland A3 plotter, i have 300mw red laser, it will etch 30 thou black styrene card though 10 thou would be better, the idea was to make stencils as mentioned b4, two things i need to do, slow down the plotting speed it moves too fast, and a fan to blow away the smoke, the beam is defused by the smoke and optical power is reduced, also i think a laser higher up into the IR spectrum would work better

By: svofski

svofski — Mon, 26 Oct 2009 13:34:14 +0000

No, they’re not enough. But they, as well as a floppy, act as a very dense filter that helps to relieve eye stress from watching the extremely bright spot where the light is focused.

By: Johnboy

Johnboy — Mon, 26 Oct 2009 13:25:35 +0000

WTF is this guy wearing a floppy disk platter as an eye patch for? Crazy.
Also, are (what look like) sunglasses really enough to prevent burning a hole in your eye with a 300mW laser?

By: svofski

svofski — Mon, 26 Oct 2009 09:24:53 +0000

@Andrew; 0.8 mm is not a very fine trace. The Motori itself has a PCB with traces ranging from 0.3 (narrow places near fine-pitch IC’s) to 0.4 (general signals) up to over 1mm (power busses) wide.

Re: precision in general: the motors can position very finely, stepping at some 0.2mm I guess (they are different on two axes so I have different calibration in the firmware). But the end precision you get on paper is a sum of belt play, drive play, bridge play and oscillations, pen holder play etc.. The results are consistent though.

If anyone really would want to make something practical out of a project like this, it would be a foam or stencil cutter for RC models, or small signs, something like that. With a 300mW laser the orders are not going to be very quickly served, too ;)

By: googfan

googfan — Mon, 26 Oct 2009 04:19:56 +0000

that was the image on the pioneer plaque.

http://en.wikipedia.org/wiki/Pioneer_plaque