Need a simple fab process to go from a humble vector graphic to a final part — in a matter of minutes? The CO2 laser cutter might be the right choice. As these tools open themselves up to widespread use through hackerspaces, I decided to give Delrin some well-deserved time under the spotlight.
This guide is a brief collection of tips and techniques that I’ve either learned from others or discovered on my own over the last couple years working with laser-cut Delrin (a.k.a Acetal) for functional prototypes. I hope this guide serves you well as we keep exploring the limits of the material.
As a disclaimer, keep in mind that in no way are these techniques unique or limited to Delrin. Many are not only years old but also common practice in either engineering design or the local machine shop. This article simply highlights the techniques shown here that perform both repeatably and predictably with Delrin and a couple hand-tools, and I hope to share them with a growing audience of laser cutter enthusiasts.
Actors want to be singers and singers want to be actors. The hacker equivalent to this might be that 3D printers want to be laser cutters or CNC machines and laser cutters want to be 3D printers. When [Kurt] and [Lawrence] discovered their tech shop acquired a 120 Watt Epilog Fusion laser cutter, they started thinking if they could coax it into cutting out 3D shapes. That question led them to several experiments that were ultimately successful.
The idea was to cut away material, rotate the work piece, and cut some more in a similar way to how some laser cutters handle engraving cylindrical objects. Unlike 3D printing which is additive, this process is subtractive like a traditional machining process. The developers used wood as the base material. They wanted to use acrylic, but found that the cut away pieces tended to stick, so they continued using wood. However, the wood tends to char as it is cut.
In the end, they not only had to build special jigs and electronics, they also had to port some third party control software to solve some issues with the Epilog Fusion cutter’s built in software. The final refinement was to use the laser’s raster mode to draw surface detail on the part.
The results were better than you’d expect, and fairly distinctive looking. We’ve covered a similar process that made small chess pieces out of acrylic using two passes. This seems like a natural extension of the same idea. Of course, there are very complicated industrial machines that laser cut in three dimensions (see the video below), but they are not in the same category as the typical desktop cutter.
If there’s one thing about laser cutters that makes them a little difficult to use, it’s the fact that it’s hard for a person to interact with them one-on-one without a clunky computer in the middle of everything. Granted, that laser is a little dangerous, but it would be nice if there was a way to use a laser cutter without having to deal with a computer. Luckily, [Anirudh] and team have been working on solving this problem, creating a laser cutter that can interact directly with its user.
The laser cutter is tied to a visual system which watches for a number of cues. As we’ve featured before, this particular laser cutter can “see” pen strokes and will instruct the laser cutter to cut along the pen strokes (once all fingers are away from the cutting area, of course). The update to this system is that now, a user can import a drawing from a smartphone and manipulate it with a set of physical tokens that the camera can watch. One token changes the location of the cut, and the other changes the scale. This extends the functionality of the laser cutter from simply cutting at the location of pen strokes to being able to cut around any user-manipulated image without interacting directly with a computer. Be sure to check out the video after the break for a demonstration of how this works.
Modern computers are rubbish. Why, they barely have a switch or a blinky light on them. What’s the point in having a computer if you don’t have the thrill of throwing a switch or eight and watching lights blink in response? [Smashcuts] obviously agrees because he built a control panel filled with heavy-duty switches and blinking wonderfulness to augment his battlestation. This piece of mechanical wonderment has buttons for useful features such as typing several levels of derisive laughter in chat windows, playing odd sound effects and a large red panic button that… well, I won’t spoil the surprise. The whole thing is hand-wired and fronted with laser-cut panels that make it look really authentic. [smashcuts] built it “because it didn’t exist and I felt like it needed to”, which is a perfect justification for this piece of industrial scale awesomeness.
It does have some more practical uses, though: he has set several of the switches to trigger actions in Photoshop and other programs, so this could be easily adapted for those who have the odd belief that things need a practical use to exist. He used USB controllers from Desktop Aviator, and a Mac program called Controller Mate to set up the sequencing for the blinkies. Unfortunately, [smashcuts] didn’t produce a how-to guide for this panel, claiming that “I don’t really have blueprints or schematics. I REALLY didn’t know what I was doing, so all the notes I do have wouldn’t make sense to anyone. It’d be like reading an owners manual to a car written by a caveman”. Either way, it is an impressive build, and you can find more details from the creator on this reddit thread.
[Amanda Ghassaei] has created an awesome hack for making your own vinyl records using a laser cutter from an MP3 file. Her excellent hack uses a Processing sketch that converts a digital audio file into a vector graphics file, which is then burned onto vinyl using a laser cutter. We saw a demo of this at the FabLab11 conference, and it’s an impressive hack.
Audiophiles should avoid this technique though. Due to limitations in the resolution of the laser cutter, [Amanda] ended up having to reduce the bandwidth of the audio signal to 4.5Khz and use a 5-bit sampling depth. That translates to a rather tinny-sounding record. Vinyl record snobs can breathe easy: this isn’t going to replace their beloved white-hot stampers. For the rest of us, there are always records etched into tortillas.
You’re going to want to take a look at this fun project [Alistair MacDonald] just finished up. He calls it Ninja Chess.
He’s had the idea to 3D print a complete set of ninjas vs pirates for a chess board, but, let’s be real; printing thirty-two chess pieces would take a long time. He opted to use a laser cutter instead, and so far, only has the Ninja characters drawn. But it still makes for a pretty awesome chess board.
He drew the characters in Inkscape and they’re pretty darn cute. He has all the files available over on his Instructable including the .DXF for the laser cut outlines, and the image files for you to print off the decals. But unless you’re good with scissors, we recommend using your hackerspace’s automated paper cutter to help speed things up.
Is it a hack? Not really, but it’d be an excellent addition to anyone’s workshop. And while we sail under the Jolly Wrencher, we too can appreciate the novelty of a Ninja chess board.
For a more detailed build, did you see the 3D laser cut chess pieces we shared a few weeks ago? No that’s not a typo — you can use a laser cutter to do more than just two-dimensional cutting…
Uncooked flour tortillas were used. Corn tortillas were too lumpy while cooked tortillas shredded on the record player. To get the recording onto the tortilla, Audacity was used to modify a stereo WAV file. Using the RIAA equalization standard is a great choice here as it was originally adopted to prevent excess wear and tear on record grooves as the needle passed through. A Python script generated the files for the laser cutter, creating a text file with the sound data which was then processed into a vector PDF of the grooves. For each record it takes 30 minutes for the laser cutter to turn a simple flour tortilla into the musical variety.
Each tortilla can play 30-40 seconds of music at 45 or 78 RPM, but they start to warp once they dry out. Time to build a humidor around the record player! There is background noise that can make certain songs harder to hear, but there is unarguably audible music. There is plenty of room for optimizing the sound file, grooves, and cutting. We hope this project inspires others to make their own musical tortilla. Playing with your food has taken on a whole new meaning!