Printable Carbide Opens Up Interesting Possibilities

April 15, 2022 by Al Williams 23 Comments

Sandvik, a large company headquartered in Sweden, has apparently been producing cemented carbide for a long time — according to them, since 1932. The material is known for being highly wear-resistant. Now the company says they have a process to 3D print the material. You can see a video about the new material, below.

If you haven’t encountered this material, it is essentially fine carbide particles bound in metal. You’ll find the material widely used in cutting tools. The slogan “Freedom of Design has Never Been Harder” is both clever and confusing, but we took their point.

The process is more or less like other metal binder technology. A powder of tungsten carbide and cobalt mixed with glue creates a green body which you still need to fire to get to the finished part.

What kind of things can you make? Here’s a quote from one of Sandvik’s engineers:

For instance, in wire drawing, productivity is usually limited by how fast the wire can be drawn with maintained quality, which in turn depends on the temperature in the wire drawing die. People have been trying to solve this problem for decades, but it’s been extremely difficult. A 3D printed, cooled wire nib is the answer to this riddle. It took a mere four days to produce, from the first basic sketch to the fully sintered product – thanks to our materials and proprietary process.

Don’t plan on loading up your Ender 3 with cemented carbide filament. This is, after all, a metal material. However, 3D printing can offer geometries that would be difficult to obtain with traditional methods. So even if you have to turn to a professional 3D printing shop, it is good to know you can create in this ultra-hard material.

Printing in metal has a different set of issues than using plastics. If you really want your current printer to do metal, it can, but you’ll have to cheat a bit. Or try electroplating.

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Reducing Warping In Metal 3D Prints

April 13, 2022 by Al Williams 9 Comments

We are used to dealing with warping when printing with thermoplastics like ABS, but metal printers suffer from this problem, too. The University of Michigan has a new technology, SmartScan, that promises to reduce this problem. You can see a video about the technique, below.

The idea is to develop a thermal model of the printed part before laser sintering and then move the laser in such a way that heat doesn’t accumulate. The video shows how engraving metal in the traditional way causes the metal to warp as the laser heats up areas. Using the SmartScan thermal model, they were able to reduce deformation by almost half.

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Don’t Tune Your 3D Printer To Middle ‘C’ After All

April 3, 2022 by Dave Rowntree 22 Comments

Layer shift caused by the belt being way too loose.

3D printer belt tension seems like a simple thing to deal with — you set the tension and then check it’s good now and then. If it gets really loose, then the teeth can slip and you’ll get some shifts in the print, ruining it, but its an easy fix. But, we hear you ask, how do you determine what the correct tension is? Well, here’s [Lost in Tech] with a video showing some measurement techniques and analysis of a typical 3D printer, (video, embedded below) using nothing more special than a set of luggage scales. A simple theory suggested was that a tighter belt tension would result in increased radial load on the stepper motor bearings, which in turn, due to friction, would result in an increase in temperature of the motor. After setting a few tension values on one of the belts, it was noted that tension values at the upper end of the range, resulted in a measured increased in temperature of two degrees celcius, and a large increase in noise. This can’t be good for the motor.

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Texture Map GCode Directly In Blender With NozzleBoss

March 31, 2022 by Dave Rowntree 5 Comments

We’ve seen this funky dual disk polar printer already recently, but [Heinz Loepmeier] has been busy working on it, so here’s an update. The primary focus here is nozzleboss, a blender plugin which enables the surface textures of already sliced objects to be manipulated. The idea is to read in the gcode for the object, and convert it to an internal mesh representation that blender needs in order to function. From there the desired textures can be applied to the surfaces for subsequent stages to operate upon. One trick that nozzleboss can do is to create weight maps to tweak the extrusion flow rate or print velocity value according to the pixel value at the surface — such ‘velocity painting’ can produce some very subtle surface effects on previously featureless faces. Another trick is to use the same weight maps and simply map colours to blender text blocks which are injected into the gcode at export time. These gcode blocks can be used swap tool heads or extruders, enabling blending of multiple filament colours or types in the same object.

Some nice examples of such printing manipulation can be seen on [Heinz’s] instagram page for the project. So, going back to the hardware again, the first video embedded below shows the ‘dual disk polar printer’ fitted with a crazy five-extruders-into-one-nozzle mixing hotend setup, which should be capable of full CMYK colour mixing and some. The second video below shows an interesting by-product of the wide horizontal motion range of the machine, that the whole printing area can be shifted to a nozzle at the other end of the gantry. This enables a novel way to switch extruders, by just moving the whole bed and print under the nozzle of interest! One final observation — is that of the print surface — it does look rather like they’re printing direct onto a slab of marble, which I think is the first time we’ve seen that.

Interesting printer designs are being worked on a lot these days, here’s a really nice 5-axis prusa i3 hack, and if you want to stay in the cartesian world, but your desktop machine is just too small, then you can always supersize it.

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the water gravity air powered engine running

Gravity-Water-Air Powered Engine

March 28, 2022 by Matthew Carlson 19 Comments

Air engines are a common occurrence here on Hackaday. They’re relatively novel and reasonably easy to 3D print without requiring any fluids or supporting machinery. For example, [Tom Stanton] took a previous air engine design, did away with the air compressor, and instead used gravity and water to create just a few PSI to run the engine.

The basic setup is to have a large jug of water up somewhere high. Flexible tubing runs down to [Tom’s] custom acrylic pressure chamber. A little CNC-ing and some epoxy made a solid chamber, and we’re happy to report that [Tom] did some initial simulation before construction to make sure he wasn’t accidentally building a bomb. Some back of the napkin math showed that he could expect around 0.6 bar (around eight psi) with his setup. His first test showed almost precisely that. Unfortunately, [Tom] ran into some issues despite the early success. His engine would stop as it drew air and the pressure dropped, and the replenishing rate of the pressure was limited by the relatively small inlet hole he had drilled.

To fix this, he printed a larger diaphragm for the engine, so the lower air pressure had more to push against. This allowed the engine to run for a good while before the tank filled up. Additionally, he smoothed and polished everything, so it was as low friction as possible. We know we often state it here, but it is incredible what can be achieved with 3D printed parts these days.

We love seeing the iteration evident in this video. The various engine versions splayed across the table offer a powerful story about [Tom’s] persistence. Powering an engine is a small step to powering your whole home.

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3D Printed Portal Turret Moves And Talks Like The Real Thing

March 27, 2022 by Robin Kearey 19 Comments

Thanks to its innovative gameplay and quirky humor, Portal became an instant hit when it was released in 2007. Characters became cultural icons, quotes became memes and the game became a classic along with its 2011 sequel. Even today, more than a decade later, we regularly see hackers applying their skills in recreating some of the game’s elements. One beautiful example is [Joran de Raaff]’s physical rendition of a Portal Turret.

A 3D CAD drawing of a Portal Turret — Inside the Turret it’s full of moving parts.

[Joran] decided to use his 3D printer to create a Turret that can move and speak exactly as it does in the game. The result, as you can see in the video embedded below, was a triumph. We’re making a note here, “huge success”. The outer shell is a beautiful shiny white, an effect achieved through patient sanding, priming, and spraying with high-gloss paint. The internals are even more impressive with servos, microswitches, and a whole array of 3D-printed gears, cams, and levers.

A motion sensor activates the Turret whenever a human moves nearby. It will then open its wings and fire its guns while playing the corresponding sounds from the game. Its brains are formed by a Wemos D1 which drives the various LEDs and servos, while an MP3 player board holds a library of sound bites and plays them through a speaker hidden inside the Turret’s shell.

After posting his creation on YouTube [Joran] got many requests for the 3D files, so he made them available and wrote a comprehensive build guide. This should enable anyone with a 3D printer to build this neat gun, without getting too much science done. If this model is too small for you, then perhaps this life-sized model is more to your liking. If you prefer your Turret small and cute, check out this plushie version.

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3D Printed Forge For Recycling

March 27, 2022 by Matthew Carlson 30 Comments

If you own a CNC and have kept tabs on metal prices these past few years (honestly months), you might shed a small tear as you watch chips fly off your work and into the trash. With a sigh, these flecks and pieces are consigned to be the cost of machining a part. Thankfully, the fine folks at [ActionBox] have been working on a 3d printed plaster forge for recycling their metal scraps.

The team ordered some graphite crucibles of a few sizes from a large online bookstore and started 3D printing some molds for crucible holders. They started with a smaller version to try the method. While the walls were too thin in that initial version, the approach was proven. With slightly thicker walls, the medium-sized version worked much better. The goal of the forge was to smelt copper as they had a lot of thick copper wire lying around. Armed with several propane torches, they started melting aluminum and brass, which worked reasonably well. However, the melting point of copper continued to elude them (1984°F or 1085°C). To counter this, the [ActionBox] team bought some new torches that provided significantly higher BTU output, while still fitting the holes in the mold. This did the trick!

The mold to accommodate the large crucible was massive and printed in four sections. The team did melt copper successfully and had four ingots to show off. We want to stress how dangerous molten copper and other metals are, particularly regarding things you might not realize have moisture soaked up inside. Proper PPE is essential to use these things without getting hurt. [ActionBox] has some helpful pointers in that area, but they admit they are relatively new to forging and casting themselves. Perhaps version two can incorporate a flip lid for added safety.

Video after the break.
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