Home-made CNC laser engraver

Before you go any further, please take a minute to consider your eyes. You only have two of them, and they’re not replaceable. You need both for certain applications. Lasers are dangerous, and they can burn flesh: please be careful around them.

And with that out of the way…

I found this project on our forums, and it knocked my socks off. Daniel Chai has made something incredible with a Pi and parts salvaged from a pair of optical drives: a very low-priced, fine-resolution laser engraver. This differs from Arduino-driven engravers we’ve seen before: Daniel only uses a Pi, and he’s written his own control system, where his Python interprets G code and drives the stepper motors on both axes at the same time.

Engraving in progress

Final output

Daniel says:

The reason why I choose Raspberry Pi is: it is a much more powerful device than Arduino; it has a complete OS; the GPIO pins can be controlled by python, a more intuitive and simpler language than C (the disadvantage of python would be the slow speed); I don’t have to buy a separate controller for this project–I can use a single Raspberry Pi to do a lot of different things without reloading firmware. Most importantly, I have a Raspberry Pi but don’t have an Arduino right now!

The most expensive parts of this project, namely the stepper motors and laser diodes, were salvaged from two old DVD writable drives which had been abandoned as e-waste. (DVD drives are much preferable to CD drives, which can be ultra-dangerous because their laser is an infra-red laser, invisible to the naked eye – don’t go poking around the innards of those if you value your eyesight.) Other parts of those drives are also used to make a tray to hold the item being engraved: this is a thrifty project.

Daniel has made everything you’ll need, from a parts list, instructions on liberating the bits you’ll need from the DVD drives, all the relevant code, wiring diagrams and tips on construction, on his website. This is an advanced project with lots of different stages to it, but it’s inexpensive and yields extraordinarily professional (and expensive-looking) results. We’d love to hear from you if you attempt your own build.

50 comments

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Possibly one of the best applications I have seen so far for the raspberry pi!

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That is brilliant and terrifying.

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Next step: Fly killer laser turret (automatic)

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EXTERMINATE!!

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Remember the traditional warning sign in Laser labs – Do Not Stare Into Laser With Remaining Eye!

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Love It..

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Let’s not forget the backronym,
Looking At Source Erases Retina

(originally spotted in New Scientist iirc)

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Cool!

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Well, I thought the kids in class would behave when I had to resort to installing a Pi NoIR camera to monitor them when my back was turned while working on the (yes, singular) classroom desktop computer. A mouse cable and two phone cables mysteriously wound up cut – the culprits apparently don’t watch much in the way of CSI type TV shows and aren’t aware their fingerprints are unique, not to mention their DNA (courtesy of a bio-science project we’re running). Now, I’m going to have to wear laser-proof goggles and keep moving fast enough to not wind up being called “Lefty”!

Despite such challenges, keep ’em coming, kids! This is real STEM learning in action, and the fact that Daniel is rescuing e-waste from the environment, as well as minimizing cost, are outstanding pluses. This is engineering at its finest and greatest!

People ask me all the time what the difference between being a scientist and engineer is since I’m both. I reply it’s that engineers are required to take economics when earning their degree, while scientists are not. That’s because engineers have to deliver precisely-specified things within schedules and budgets, while scientists often don’t know what it is they’re actually accomplishing until after it’s done, and then they add up the cost (as no military battle plan survives contact with the enemy, no scientific budget survives contact with reality – Murphy is such a cad! :lol: ).

Then there’s the jokes about why no engineers survived the French Revolution due to pointing out defects in guillotines about to fail to operate properly in their executions. Yet we can succeed in lusty endeavo(u)rs when confined in a room with a reclining nude against an opposing wall and are allowed to advance half the distance to them as successive minutes tick away on a wall clock.

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Ha, funny! Your attitude toward your class is great. Keep up the good work.

The last joke is pretty funny, but I wouldn’t say that the lusty endeavor is a success, as we know that halving will, for all intents and purposes, cause only frustration as it takes FOREVER to get to the point where we’d consider we’d “touched”. XP

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I’d love to do something like this as a portable laser cutting station. Just have no idea how.

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This is a laser engraver using a 200 milliwatt laser diode capable of only singeing the surfaces of most materials. True laser cutters use chemical lasers (not solid-state/semiconductor) that start around 50 ~ 70 watts and can cut up to a few millimeters-thick wood and plastic, but not metal materials. The latter requires chemical lasers with well above 100 watts of power for just the thinnest metal foils, and hundreds to thousands of watts to cut metals of greater thickness and melting/vaporization temperatures.

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there are some solidstate laser in the 100 watts range… through for the real laser cutting source, wich runs in the 3-6kw range you fall back on some chemical source

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I worked at UKAE as a student 30 odd years ago – they had REAL lasers there! Need to cut through 1/4″ stainless steel? No problem. Someone had mounted a laser on an old dentist’s drill mount for cutting stuff by hand. It came in really handy for accurate cutting of ceramic tiles when tiling the kitchen/bathroom. The most impressive thing I saw though was a 4″ fire brick with a hole burnt clean through it. You didn’t look into those lasers twice either!!

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Most low cost CNC laser cutters or routers usually use a CO2 gas laser not a chemical laser. These operate at 10.6um in the far infrared. Other lasers used in more expensive CNC setups are solid state lasers like YAG DPSS ( Diode Pumped Solid State) operating at 1.06um in the near infrared. Ytterbium fiber lasers are the latest high power DPSS technology that also operate at 1.0um but produce very small laser spots ideal for ultra precision micro-machining. Diode lasers like the one used here are limited in power and have a medium spot size but are very cheap. Laser power and wavelength needs to selected for the material being processed. Perspex is easily cut with CO2 lasers. Metal is very difficult to cut with most lasers due to its high reflectivity (~99%) at most laser wavelengths. Do not forget to wear laser safety goggles !

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This is brilliant. What materials can it cut & how deep?

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If this is the same project I looked at a couple days ago, it will cut paper stencils, and I believe business cards.

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This is a laser engraver using a 200 milliwatt laser diode capable of only singeing the surfaces of most materials. True laser cutters use chemical lasers (not solid-state/semiconductor) that start around 50 ~ 70 watts and can cut up to a few millimeters-thick wood and plastic, but not metal materials. The latter requires chemical lasers with well above 100 watts of power for just the thinnest metal foils, and hundreds to thousands of watts to cut metals of greater thickness and melting/vaporization temperatures.

We use laser cutters to fabricate model railroad structures and loco/rolling-stock shells for our Silicon Valley based Z scale group layout, and one of our members works with a 35,000 watt laser to anneal semiconductor wafers in preparation for their use in semiconductor device fabrication facilities (fabs).

The warnings about being careful with lasers must be heeded, even for a 200 mw laser diode. Retinas really are extremely fragile things that such focused energy can destroy in microseconds.

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I wonder if I can use this to print (burn?) images on a toast….

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I would think so.

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Nice idea, though the link to the blog spot shows empty pages. Has the link changed?

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I would suggest that anyone building this consider mounting in inside an opaque enclosure with a door that can be shut while it’s in operation. Failing that, ay least cover the thing with a large cardboard box before firing it up. Remember that shiny things can reflect a beam in unexpected directions, and that kids and pets have a tendency to wander into places when least expected and don’t understand why they shouldn’t look at the pretty red light.

In a way it scares me that this type of technology is available because you know that someone, somewhere is going to misuse it. Giving a person with no concern about safety access to a burning laser is a bit akin to giving a child a loaded gun. I can see why this project could attract a lot of interest (we probably all have things we’d like to engrave) but ideally such a device would be set up in such a way that there’s little risk of accidentally burning body parts.

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I agree! I also think we should ban forks. And fire. You can’t be too careful.

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I wasn’t suggesting we ban this, just that maybe there should have been some conspicuous warnings and safety suggestions at the original link. While we may like to think that anyone bright enough to build one of these doesn’t need a warning, that ignores the fact that most bright people have some not-so-bright people among their friends and family. There are a LOT of stupid people in the world, unfortunately. And even smart people sometimes get distracted and forget basic safety.

Have you ever tried to start a microwave while the door was still open because you were distracted and not paying attention? I have, and therefore I’m sure glad there are safety interlocks in the door. People do dumb things when they are sleepy, drunk, or high.

That said, I would be very much against any effort to outright ban such a device. I realize you were probably just being sarcastic, but don’t give the “safety nannies” that would like to put all of us in rubber rooms from cradle to grave any ideas!

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I would mostly be concerned about eye saftey. Search the internet for vendors of blue lasers. They will sell protective goggles for use with the blue laser.

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Sorry, I spoke with reading this project more thoroughly. I have confused it with another project. This project use an IR led, dangerous because you cannot see it. However, the vendors of diode lasers do sell goggles protective against IR lasers.

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He’s using a visible red laser. To quote from the article: “you need 200mW laser diode from DVD writer. A DVD R or CD R will do nothing. A CD writer might be OK in term of power (~100mW), but the laser diode of a CD writer is infrared, which can be super dangerous (you can’t see it!).

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Very very cool!
I have the remains of an old RepRap 3D Printer here, been looking to do something with it for a while. Maybe this is it…

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i have another possible use, if ppl dont want to get into buring acrylics,, and that is to lightly etch close space patterns into the roscolux lighting gel that comes with the pi noir.
i know we can apply all sort of effects as post processing, but having the old Hoya-style optical filters of starbursts, spangles etc gets creative juices going in real time at the point of capture. and it the spirit of pi.venture

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Remarkably well documented project!

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Having built a CNC router this would be a minimal attachment and somewhere I have a box full of and 7805s and old CD players and maybe one of them is a DVD R/W and so I spent the rest of the evening reading /printing /loading /updating inkscape, dxf2gcode et al and another day is done and I’m running out of heart beats but the dawn is here and we must shovel snow.

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Daniel Chai,
You are a technology hero!

This will be a brilliant project to try out. Many thanks for making this information available to lesser mortals.

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LASERS! AWESOME!

Anyone got a RPi controlled shark we can mount them on?

(Is that too much to ask?)

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This is so awesome I’ve ordered some power units and some stepper controllers from hong kong. Hopefully they will be here for xmas. Got some cheap (£7) safety goggles too hopefully they are good enough to keep me safe.

Spent £11.04 excluding goggles \o/

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This is really cool work. Could this be used to etch small run PCB’s for home projects.

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Any chemists / metallurgists out there: Is there a metal based liquid / powder we could put on a substrate for use with this laser to make small PCBs ? I am inspired by the EX1 on Kickstarter, but the price is way beyond me.

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By pulsing the laser you could get higher instantaneous power?
By using a small source of infra red heat that warmed the general area where the laser was pointing perhaps it could cut more?
Great project what ever the limitations.

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I fancy this for making pcbs but i guess the laser will not be powerful enough to burn the copper from a copper-clad blank?
Does anyone know of a cheap source of lasers powerful enough to do this or is it not even possible?

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Why not us a UV device on photo-sensitized boards?

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And the fun part of that is……?
I would much rather spend a couple of fascinating weekends building a CNC laser PCB maker instead of simply buying the UV kit.
Even if the CNC didn’t produce quite as good a final product i’d still rather do that just for the crack.
Of course it’s pointless if it wouldn’t work at all hence the question.

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Hmm, it would seem the Arduino is doomed ….. I mean, written it C – its just too much. RPi is simpler.

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Fascinating project, a little scary in the wrong man cave

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Next we need to make a CNC lathe. :) I think this is a good start with the stepper motors scripts to use those to guide a traditional lathe.

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Great stuff !

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It would surly cut cotton material. I am a quilter and need applique pieces cut
from time to time

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I was wondering if this engraver could be used to directly burn away the photoresist on prototype PCBs to produce a board that could then be chemically etched. This would eliminate the need to produce UV film masters and the associated development process.

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I think it is better to use the mechanism of a scanner (A4) to have a larger area of working (two of them, probably used from recycling)
I think I will try this, I was thinking this before I read this article.
Can you give an address where to buy protection glasses?

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Why when I cleck on all you need I keep getting a error message and it keep reloding?

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Well done…You try with an Ardunio?

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