To exclude musical instruments in the overflowing library of possibility that 3D printing enables would be a disservice to makers and musicians everywhere. For the minds over at [Makefast Workshop], an experimental idea took shape: a single stringed harp.
The TuneFast Harp needed enough notes for a full octave, robust enough to handle the tension of the string, a single tuning mechanism and small enough to print. But how to produce multiple notes on a harp out of only one string? V-grooved bearings to the rescue! The string zig-zags around the bearings acting as endpoints that rotate as its tuned, while the rigid PLA printing filament resists deforming under tension.
After a bit of math and numerous iterations — ranging from complete reconfigurations of part placements to versions using sliding pick mechanisms using magnets! — a melodic result!
Have a look at the object to the right. Using a conventional fused deposition printer, how would you print the object? There’s no flat surface to lay on the bed without generating a lot of overhangs. That usually requires support.
In theory, you might be able to print the bottom of the sphere down, but it is difficult to get that little spot to adhere to the bed. If you have at least two extruders and you are set up to print support material, that might even be the best option. However, printing support out of the same material you are printing with makes it hard to get a good clean print. There is another possibility. It does require some post-processing, but then again, not as much as hacking away a bunch of support material.
A Simple Idea
The idea is simple and — at first — it will sound like a lot of trouble. The basic idea is to cut the model in half at some point where both halves would be easy to print and then glue them together. Stick around (no pun intended), though, because I’ll show you a way to make the alignment of the parts almost painless no matter how complex the object might be.
The practical problem with gluing together half models is getting the pieces in the exact position, but that turns out to be easy if you just make a few simple changes to your model. Another lesser problem is clamping a piece while gluing. You can use a vise, but some oddly-shaped parts are not conducive to traditional vise jaws.
In Practice
Starting with an OpenSCAD object, it is easy to cut the model in half. Actually, you could cut it anywhere. Then it is easy to rotate half of it so the cut line is at the bottom of each part. That doesn’t solve the alignment problem nor does it help you clamp when you glue.
The trick is to build a flange around each part. The flanges mate with a few screws after printing so alignment is perfect and bolts through the flange holes can keep the parts together and immobilized while your glue of choice sets. The kicker is that I even have an automated process to make the design side of this trick very easy.
Most of our 3D printers print in plastic. While metal printing exists, the setup for it is expensive and the less expensive it is, the less impressive the results are. But there are other materials available, including ceramic. You don’t see many hobby-level ceramic printers, but a company, StoneFlower, aims to change all that with a print head that fits a normal 3D printer and extrudes clay. You can see a video of the device, below. They say with some modifications, it can print other things, including solder paste.
The concept isn’t new. There are printers that can do this on the market. However, they still aren’t a common item. Partially, this is a cost issue as many of these printers are pricey. They also often require compressed air to move the viscous clay through tubes. StoneFlower has a syringe pump that doesn’t use compressed air.
Although we tend to think of 3D printers as high-tech toys, most of them are not especially powerful in the brain department. There are some exceptions, but most 3D printers run on either an 8-bit Arduino or some Arduino variant with a lot of I/O. There are a few 32-bit boards, but if you grab a random 3D printer, its brain is going to be an 8-bit AVR running something like Marlin or Repetier. It isn’t uncommon to see a Raspberry Pi connected to a printer, too, but — again, in general — it is a network interface that handles sending G-code to the 8-bit controller that runs the stepper motors. Would it make more sense to do things like parse G-code, map out curves, and set accelerations in the relatively powerful Raspberry Pi and relegate the 8-bit AVR to just commanding motors and heaters? [KevinOConnor] thinks so, and he wrote Klipper to prove it.
Klipper is mostly written in Python and it does most of the functions of traditional 3D printing firmware. It communicates with the onboard microprocessor by providing a schedule of when to do what tasks. The microprocessor then handles the timing and things like motion control for the axes and extruder. Klipper can control multiple microprocessors with no trouble and keeps them in synchronization, so you could have a processor for your extruder and one for each stepper, for example. You can use Klipper with a Cartesian machine, a delta, or a Core XY-style printer.
There’s an old saying, that in theory there’s no difference between theory and practice, but in practice there is. That sentiment could easily be applied to refitting a 3D printer to hold a laser. There shouldn’t be much to it, rig up a laser module to turn on under computer control, mount it to your hot end carriage and off you go. In practice, though there are other considerations to account for. If you have a Monoprice Mini Select, you can start with instructions from [drodrii] for adding a laser to your printer.
Although [drodrii] mentions that you need a second 3D printer to make a bracket for the laser, we think you should be able to print it on the Mini as long as you do it before the first step of removing the hot end. However, since your laser module might not exactly match the one used in this project, you’d have to get it right the first time if you don’t have another 3D printer. Of course, you could remove the laser gear, remount the hot end, print a new bracket and start over, but that’d be a drag.
When it’s time to put together the annual Christmas card, most families take a few pictures of the kids, slap on a generic greeting, and call it a day. It used to be fairly common for the whole family to get dressed up and pose for a special Christmas picture, but who has the time anymore? It’s not like we have hours and hours to slave over a unique and memorable gift we can mail out to a dozen (or more) people.
As it turns out, getting sound into CAD software isn’t exactly straightforward. To start, he made a recording of his daughter saying the words “Happy Christmas From the Wolsey Family” with Audacity, and then took a screenshot of the resulting waveform. This screenshot was then brought into Adobe Illustrator and exported to SVG, which Fusion 360 (and most other CAD packages) is able to import.
Now that the wave was in Fusion 360 he could scale it to a reasonable size, and use the revolve function to bring it into three dimensions. Cutting that object in half down the length then gave [Chris] a shape which should, theoretically, be printable on his FDM printers. But unfortunately, it wasn’t so easy. His personal Anet A8 had a tough time printing it, and the Prusa i3 MK2 at work didn’t fare much better. In the end, he had to make the leap to SLA, getting the shape printed on a Form 2 via 3D Hubs.
With the finalized shape in hand, [Chris] just need to put them into production. Printing them all via 3D Hubs wasn’t really an option, so he decided to make a mold and cast them in resin. He printed up a mold box, and after fiddling around with the mix a bit, was able to settle on a resin which allowed him to de-mold the shapes just 30 minutes after pouring.
Finally, he made frames for each cast waveform, and printed up a little label explaining just what the recipient was looking at; even going as far as showing which word corresponded to which section of the shape.
This is a fantastically executed and documented project, and while it’s too late to whip up your own version this year, we have no doubt they’ll be a few people “borrowing” this idea next time the holidays roll around.
A few months ago, [Marco] picked up a cheap, cheap, cheap laser engraver from one of the familiar Chinese resellers. It’s a simple affair with aluminum extrusions, a diode laser, and a control board that seems like it was taken from a 3D printer controller designed five years ago. Now, [Marko] is building some upgrades for this engraver and his PCB production skills have gone through the roof.
The laser engraver [Marko] picked up is called the EleksMaker, and lucky for him there are quite a few upgrades available on Thingiverse. He found two 3D printable parts, one that keeps the belt parallel to the aluminum extrusion, and another that provides adjustable x-axis tightness on the belt. With these two mods combined, [Marko] actually has a nice, smooth motion platform that’s more precise and makes better engravings.
These upgrades weren’t all 3D-printable; [Marko] also got his hands on a few Trinamic TMC2130 stepper motor drivers. These stepper drivers are the new hotness in 3D printing and other desktop CNC machines, and looking at the waveform in an oscilloscope, it’s easy to see why. These drivers produce a perfectly smooth waveform via interpreted microstepping, and they’re almost silent in operation. That’s terrible if you want to build a CNC chiptune player, but great if you want smooth engraving on a piece of copper clad board.
This project has come a long way since the last time we took a look at it a few months ago, and the results just keep getting better. [Marko] is making real PCBs with a laser engraver that cost less than $200, and the upgrades he’s already put into it don’t add up to much, either. You can take a look at [Marko]’s progress in the video below.
