Chilling in the pool is great, but what a drag to have to get out to grab a cold brew. [Alister] had his eye on a commercial drink float, but the company was out of business. But 3D printing, of course, comes to the rescue in this video, also embedded below.
The payload amounts to four bottles and some snacks. Brushless thrusters allow the bartender to steer the little robot around the pool to deliver libations.
Prolific maker [Jan Mrázek] shared his process for casting soft silicone parts that nevertheless have some added stiffness, which he accomplished by embedding porous, 3D-printed “ribs” into the pieces during the casting process. The 3D-printed inserts act as a sort of skeleton, and as a result, the parts have a soft silicone surface but gain structure and rigidity that simply wouldn’t be obtained if the part were cast entirely in silicone. The nice thing is that no new materials or tools were needed; [Jan] 3D printed both the molds for the parts as well as the structural inserts. It’s always nice when one can use the same tool and materials to accomplish different functions.
The parts [Jan] is making are interesting, as well. He observed that the process of swapping resin in his printer’s build tank was an unpleasant experience for a number of reasons, chief among them being that resin is sticky and messy, and the shape of the build tank doesn’t make pouring resin from it a clean job.
His solution was to design a pour spout that could be pressed onto the build tank, and some specially-designed squeegees to allow scraping the tank clean with ease. Silicone is the ideal material for the parts because it turns out that sticky resin beads nicely on silicone’s surface. Anywhere else, resin tends to spread out and form a sticky mess, but on silicone resin it forms tidy drops and is much easier to clean up.
It’s a technique worth keeping in mind, because one never knows when it could come in handy. Fabricating soft robots for example tends to involve silicone casting and clever techniques. See [Jan]’s parts in action in the video, embedded below.
Continue reading “Casting Silicone Parts With 3D-Printed Inserts For Stiffness”
Since the very beginning, the prevailing wisdom regarding consumer desktop 3D printers was that they were excellent tools for producing prototypes or one-off creations, but anything more than that was simply asking too much. After all, they were too slow, expensive, and finicky to be useful in a production setting. Once you needed more than a few copies of a plastic part, you were better off biting the bullet and moving over to injection molding.
But of course, things have changed a lot since then. Who could have imagined that one day you’d be able to buy five 3D printers for the cost of the crappiest Harbor Freight mini lathe? Modern 3D printers aren’t just cheaper either, they’re also more reliable and produce higher quality parts. Plus with software like OctoPrint, managing them is a breeze. Today, setting up a small print farm and affordably producing parts in mass quantities is well within the means of the average hobbyist.
So perhaps I shouldn’t have been so surprised when I started seeing listings for these 3D printed rocket lamps popping up on eBay. Available from various sellers at a wide array of price points depending on how long you’re willing to wait for shipping, the lamps come in several shapes and sizes, and usually feature either the Space Shuttle or mighty Saturn V perched atop a “exhaust plume” of white PLA plastic. With a few orange LEDs blinking away on the inside, the lamp promises to produce an impressive flame effect that will delight space enthusiasts both young and old.
As a space enthusiast that fits somewhere in between those extremes, I decided it was worth risking $30 USD to see what one of these things looked like in real life. After waiting a month, a crushed up box arrived at my door which I was positive would contain a tiny mangled version of the majestic lamp I was promised — like the sad excuse for a hamburger that McBurgerLand actually gives you compared to what they advertise on TV.
But in person, it really does look fantastic. Using internally lit 3D printed structures to simulate smoke and flame is something we’ve seen done in the DIY scene, but pulling it off in a comparatively cheap production piece is impressive enough that I thought it deserved a closer look.
Now it’s always been my opinion that the best way to see how something was built is to take it apart, so I’ll admit that the following deviates a bit from the rest of the teardowns in this series. There’s no great mystery around flickering a couple LEDs among Hackaday readers, so we already know the electronics will be simplistic in the extreme. This time around the interesting part isn’t what’s on the inside, but how the object itself was produced in the first place.
[Integza] was reading about a World War II-era rocket plane created near the end of the war by the Germans. The Heinkel He-176 wasn’t very practical, but he was intrigued when he read the rocket was cold and combustionless. He did a little research and found the engine was a monopropellent engine using hydrogen peroxide. This led to some interesting experiments and a 3D printed rocket engine, as you can see in the video below.
Usually, liquid-fueled rocket engines have a fuel and an oxidizer that mix and are either ignited or, in a hypergolic rocket, spontaneously combust on contact. With a monopropellent, the thrust comes from a chemical reaction between the propellant — hydrogen peroxide, in this case, and a catalyst.
Researchers in Singapore and at CalTech have developed a 3D printed fabric with an interesting property: it is generally flexible but can stiffen on demand. You can see a video about the new fabric, below.
The material consists of nylon octahedrons interlocked. The cloth is enclosed in a plastic envelope and vacuum-packed. Once in a vacuum, the sheet becomes much stiffer and can hold many times its own weight.
Typically, when we think of 3D printing, we think of gooey melted plastics or perhaps UV-cured resins. However, there’s a great deal of research going on around printing special impregnated filaments with alternative materials inside. [Ahron Wayne] has been working on these very materials, and decided to make himself a brew with a prototype print.
It’s a complex process, and one that leads to some shrinkage in dimensions as well as porosity in the final part. However, where some might see failure, [Ahron] saw opportunity. The porous printed part was used to filter coffee, with the aid of a little vacuum from what sounds like a water venturi.
[Ahron] notes it’s not a particularly efficient way to make coffee but it did work. We’ve seen exciting work with steel-impregnated filaments, too. Video after the break.
Continue reading “Filtering Coffee Through 3D Printed Glass”
Need a steel beam? You can 3D print PLA beams that are as strong as a steel beam of equivalent weight according to [RepRap]. The Python code for FreeCAD generates a repeating structure especially well suited for belt printers that can print a beam of any length. Keep in mind, of course, given two things that weigh the same, if one is made of steel and the other PLA, the steel one will be physically smaller.
The beams are repeating tetrahedrons which are quite strong with a lot of material on the outer faces to resist bending. Each beam end has a neat block with a wiring hole and a ring of small holes that allow you to mount the beams to things or each other with 30 degree increments of rotation.
