Pewter Casting with PLA

Over on Hackaday.io, [bms.had] is showing his technique for 3D printing molds that he uses to cast (lead-free) pewter objects. The process looks simple enough, and if you have a 3D printer, you only need some lead-free pewter, a cheap toaster oven, and PLA filament. He’s made two videos (below) that do an excellent job of showing the steps required.

Even though the pewter is hot enough to melt the PLA, it doesn’t appear to be a major problem if you quench the piece fast enough. According to [bms.had], a slower quench will melt some PLA although that creates a smoother surface. You can see the 0.31 mm layer lines in the cast, though, although you can use any layer height you like to control that. Creating the mold is simple (the videos use Tinkercad, although anything suitable for creating 3D models would work). You essentially attach a funnel to your part and make the entire part a hole inside an enveloping shape.

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3D Printed Hydraulics

[Robert MacCurdy] at MIT wants to change how people think about hydraulics. Using fluid can be very useful in systems like robots, but it is often the case that the tubing that carries hydraulic fluid is not an integrated part of the overall design. [MacCurdy] and his colleagues have modified a 3D printer to allow it directly include hydraulic components as it prints.

The idea is simple. The team started with a printer that uses a liquid ink that is UV cured to produce solid layers. The printer has the ability to use multiple liquids, and [MacCurdy] uses hydraulic fluid (that does not UV cure) as one of the print materials. Just as you can use a 3D printer to build structures within other structures, printing the hydraulics allows for complex closed systems that use the UV-cured resin as mechanical parts that can transfer pressure to and from the hydraulic system.

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Mains Powered 3D Printer Heated Beds

Converting mains voltage down to 12 or 24VDC to drive a heating element makes no sense. To get 120 watts at 12 volts requires thick wires that can handle 10 amps, whereas at 120V, tiny 1A wires will do. If you’ve ever felt the MOSFET that switches your heated bed on and off, you know it’s working hard to pass that much current. [Makertum] is of the opinion this is a dumb idea. He’s creating a 110 / 230 V, mains-powered heated bed.

Creating a PCB heat bed isn’t an art – it’s a science. There are equations and variables to calculate, possibly some empirical measurements by measuring the resistance of a trace, but Ohm’s Law is a law for a reason. If you do things right, you can make a PCB heat bed perfectly suited for the task. You can even design in safety features like overcurrent protection and fuses. It can’t be that hard. After all, your house is full of devices that are plugged into the wall.

However, there’s a reason we use 12V and 24V heated beds – they give us, at the very least, the illusion of safety. Therefore, [Makertum] is looking for a few comments from specialists and people who know what they’re doing.

Although a mains powered heated bed sounds scary for a hobbyist-built 3D printer, there are a number of positives to the design. It would heat up faster, thin down a few parts, and significantly reduce the overall cost of the printer by not requiring another 100 Watts delivered from a 12V power supply. It’s a great idea if it doesn’t burn down the house. Anyone want to help?

3D-Printing the Most Ornate Room

It’s no secret that we like 3D printing, but Artist and architect [Michael Hansmeyer] really likes 3D printing. So much so that he’s based his entire career around exploring the artistic possibilities of what he calls “computational architecture”.

live9We first fell in love with [Michael]’s work “Columns” because it was both daring and relatively low-budget at the same time. He made a series of architectural-sized columns out of cross-sections of laser-cut cardboard. Why cardboard? Because his goal was to make the columns as complex as possible and the current range of 3D printers couldn’t give him the resolution he wanted.

 

installation3Fast-forward to “Digital Grotesque”. Now [Michael] has access to a large-scale sand printer, and the license to go entirely nuts. He makes a space reminiscent of a Rococo grotto, but full of so much detail that you can’t really take it all in: it’s nearly fractal. Some stats: 11 tons of printed sandstone, 260 million surfaces, 30 billion voxels. We’re stoked that we don’t have to dust it!

 

arabesque_wall11His latest piece, “Arabesque Wall” is partly organic and elegant, and part Aliens. If we can play art critic, we think it’s beautiful. Go click through the portfolio. (And although they never got printed, we really like some of the “Voxels” series of cellular-automata pieces.)

From new paint materials opening up new color possibilities to new instruments enabling entirely different types of music, art, and technology mutually inform each other much more than we often appreciate. In ten years time, we’ll be looking back on this work and saying “this piece looks good” and “that piece looks bad” instead of “wow, amazing tech!”. But for now, we’re also content to wallow in the “wow”.

Stronger 3D Printed Parts

When [hobbyman] wanted some 3D printed parts to attach a bag to his bike, he was worried that the parts would not be strong enough to hold when the bag was full. He decided to find a way to reinforce the part with fiberglass and epoxy. His first model had holes and grooves to be filled in with epoxy.

However, after working with the part for a bit, he decided to take a different approach. Instead of making the part nearly solid plastic with space for the epoxy, he instead created the part as a shell and then filled it with fibers and epoxy. After it all cured, a little sanding started removing some of the plastic shell and what was left was mostly a cast fiberglass part (although some of the plastic was left on).

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Print Your Own Vertices for Quick Structural Skeletons

3D printing is great for a lot of things: prototyping complex designs, replacing broken parts, and creating unique pencil holders to show your coworkers how zany you are. Unfortunately, 3D printing is pretty awful for creating large objects – it’s simply too inefficient. Not to mention, the small size of most consumer 3D printers is very limiting (even if you were willing to run a single print for days). The standard solution to this problem is to use off-the-shelf material, with only specialized parts being printed. But, for simple structures, designing those specialized parts is an unnecessary time sink. [Nurgak] has created a solution for this with a clever “Universal Vertex Module,” designed to mate off-the-shelf rods at the 90-degree angles that most people use.

uvm_configurations

The ingenuity of the design is in its simplicity: one side fits over the structural material (dowels, aluminum extrusions, etc.), and the other side is a four-sided pyramid. The pyramid shape allows two vertices to mate at 90-degree angles, and holes allow them to be held together with the zip ties that already litter the bottom of your toolbox.

[Nurgak’s] design is parametric, so it can be easily configured for your needs. The size of the vertices can be scaled for your particular project, and the opening can be adjusted to fit whatever material you’re using. It should work just as well for drinking straws as it does for aluminum extrusions.

Hair Enthusiasts Rejoice! Synthetic Follicles Are Now 3D-Printable

If you’ve been performing painstaking hair-plug procedures on your 3D-printed troll dolls, then prepare to have your world rocked! [Chris Harrison, Gierad Laput, and Xiang “Anthony” Chen] at Carnegie Mellon University have just released a paper outlining a technique they’ve developed for 3D printing fur and hair. Will the figurine section of Thingiverse ever be the same?

The technique takes advantage of a 3D printing effect that most hobbyists actively try to avoid: stringing. Stringing is what happens when the hot end of a 3D printer moves from one point to another quickly while leaking a small amount of molten filament. This results in a thin strand of plastic between the two points, and is generally perceived as a bad thing, because it negatively affects the surface quality of the print.

brush_highresTo avoid this particular phenomenon, 3D printing slicers generally have options like retraction and wiping. But, instead of trying to stop the stringing, [Chris Harrison, Gierad Laput, and Xiang “Anthony” Chen] decided to embrace it. Through extensive experimentation, they figured out how to introduce stringing in a controlled manner. Instead of random strings here and there, they’re able to create strings exactly where they want them, and at specific lengths and thicknesses.

Examples of what this can be used for are shown in their video below, and include adding hair to figurines or bristles to brushes. Of course, once this technique becomes readily available to the masses, the 3D printing community is bound to find unexpected uses for it. 

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