ceramic

32 Articles

More Microwave Metal Casting

April 16, 2024 by 10 Comments

If you think you can’t do investment casting because you don’t have a safe place to melt metal, think again. Metal casting in the kitchen is possible, as demonstrated by this over-the-top bathroom hook repair using a microwave forge.

Now, just because it’s possible doesn’t mean it’s advisable. There are a lot better ways to fix something as mundane as a broken bathroom hook, as [Denny] readily admits in the video below. But he’s been at the whole kitchen forging thing since building his microwave oven forge, which uses a special but easily constructed ceramic heat chamber to hold a silicon carbide crucible. So casting a replacement hook from brass seemed like a nice exercise.

The casting process starts with a 3D-printed model of the missing peg, which gets accessories such as a pouring sprue and a thread-forming screw attached to it with cheese wax. This goes into a 3D-printed mold which is filled with a refractory investment mix of plaster and sand. The green mold is put in an air fryer to dry, then wrapped in aluminum foil to protect it while the PLA is baked out in the microwave. Scrap brass gets its turn in the microwave before being poured into the mold, which is sitting in [Denny]’s vacuum casting rig.

The whole thing is over in seconds, and the results are pretty impressive. The vacuum rig ensures metal fills the mold evenly without voids or gaps. The brass even fills in around the screw, leaving a perfect internal thread. A little polishing and the peg is ready for bathroom duty. Overly complicated? Perhaps, but [Denny] clearly benefits from the practice jobs like this offer, and the look is pretty cool too. Still, we’d probably want to do this in the garage rather than the kitchen.
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Slab Casting – A New Way To Combine 3D Printing And Ceramics

December 20, 2023 by 11 Comments

Slip casting can be messy both in processing and in making the original plaster mold. What if there was a better way, thanks to 3D printing?

[Allie Katz] has developed a new technique using 3D printed slab molds to make ceramics. By combining the ability of 3D printing to make intricate designs and the formability of clay, they have found a way to make reproducible clay objects without all that tedious mucking about with liquid clay.

[Katz] takes us through a quick “Mould Making 101” before showing how the slab casting press molds were made. Starting with a positive CAD design, the molds were designed to eliminate undercuts and allow for air infiltration since a plastic mold can’t suck the water out of the clay like a plaster one would. Some cookie clay cutters were also designed to help with the trickier bits of geometry. Once everything was printed, the molds were coated with cornstarch and clay was pressed in. After removal, any final details like handles can be added and the pieces are then fired as normal.

If you’d like to see some more 3D printing mixed up with ceramics, check out 3D printing glass with a laser, reliable ceramic slurry printing, or this TPU-based approach.

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An array of 2D barcodes stored on a ceramic medium. Each 2D barcode is 25 micrometers wide.

Cerabyte: One Terabyte Per Square Centimeter

September 8, 2023 by 45 Comments

Most of us will at one point have run out of storage and either had to buy a larger driver or delete some of those precious files. This problem can happen to data centers, too, with the ever-increasing amount of data stored on servers across the world. [Cerabyte] aims to fix this, with their ceramic-based media promising 1 TB/cm² of areal density.

To put into perspective just how much better this density is, we can compare it against SSDs and hard drives. At the time of writing, the densest SSD (NAND flash storage) is claimed to be 0.1825 TB/cm² and the densest hard drive is claimed to be 0.1705 TB/cm², which means 5.48 times and 5.87 times more dense respectively. The density improvement doesn’t end there — both an SSD and a single HDD platter might be a couple millimeters tall, while a [Cerabyte] layer claims to be merely 50 atoms tall.

[Cerabyte] aims to create 10 PB (10,000 TB) and later 1 EB (1,000,000 TB) racks with their technology, a feat difficult to achieve with mere hard drives. The ceramic-based media is written to using lasers and read from with a microscope, though throughput is limited to a “mere” 1 GB/s, which means filling that one rack could take as long as 110 days. Despite the relatively slow access times, we think this new storage technology is impressive, assuming [Cerabyte] succeeds.

Do you need so much storage that even [Cerabyte] can’t satisfy your needs? Simply use YouTube as infinite storage!

Reliable 3D Printing With Ceramic Slurry

June 16, 2023 by 4 Comments

3D printing is at its most accessible (and most affordable) when printing in various plastics or resin. Printers of this sort are available for less than the cost of plenty of common power tools. Printing in materials other than plastic, though, can be a bit more involved. There are printers now for various metals and even concrete, but these can be orders of magnitude more expensive than their plastic cousins. And then there are materials which haven’t really materialized into a viable 3D printing system. Ceramic is one of those, and while there are some printers that can print in ceramic, this latest printer makes some excellent strides in the technology.

Existing technology for printing in ceramic uses a type of ceramic slurry as the print medium, and then curing it with ultraviolet light to solidify the material. The problem with ultraviolet light is that it doesn’t penetrate particularly far into the slurry, only meaningfully curing the outside portions. This can lead to problems, especially around support structures, with the viability of the prints. The key improvement that the team at Jiangnan University made was using near-infrared light to cure the prints instead, allowing the energy to penetrate much further into the material for better curing. This also greatly reduces or eliminates the need for supports in the print.

The paper about the method is available in full at Nature, documenting all of the details surrounding this new system. It may be a while until this method is available to a wider audience, though. If you can get by with a print material that’s a little less exotic, it’s not too hard to get a metal 3D printer, as long as you are familiar with a bit of electrochemistry.

Radio Waves Bring The Heat With This Microwave-Powered Forge

April 18, 2023 by 50 Comments

Depending on the chef’s skill, many exciting things can happen in the kitchen. Few, however, grab as much immediate attention as when a piece of foil or a fork accidentally (?) makes it into the microwave oven. That usually makes for a dramatic light show, accompanied by admonishment about being foolish enough to let metal anywhere near the appliance. So what’s the deal with this metal-melting microwave?

As it turns out, with the proper accessories, a standard microwave makes a dandy forge. Within limits, anyway. According to [Denny], who appears to have spent a lot of time optimizing his process, the key is not so much the microwave itself, but the crucible and its heat-retaining chamber. The latter is made from layers of ceramic insulating blanket material, of the type used to line kilns and furnaces. Wrapped around a 3D printed form and held together with many layers of Kapton tape, the ceramic is carefully shaped and given a surface finish of kiln wash.

While the ceramic chamber’s job is to hold in heat, the crucible is really the business end of the forge. Made of silicon carbide, the crucible absorbs the microwave energy and transduces it into radiant heat — and a lot of it. [Denny] shares several methods of mixing silicon carbide grit with sodium silicate solution, also known as water glass, as well as a couple of ways of forming the crucible, including some clever printed molds.

As for results, [Denny] has tried melting all the usual home forge metals, like aluminum and copper. He has also done brass, stainless steel, and even cast iron, albeit in small quantities. His setup is somewhat complicated — certainly more complex than the usual propane-powered forge we’ve seen plenty of examples of — but it may be more suitable for people with limited access to a space suitable for lighting up a more traditional forge. We’re not sure we’d do it in the kitchen, but it’s still a nice skill to keep in mind.

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Mac 128K Emulator Gets DIY Ceramic Enclosure

October 6, 2022 by 8 Comments

Creative technologist [Joselyn McDonald] wanted to hone her ceramic skills by building an iconic Macintosh 128K sculpture, complete with a fully functional operating system.

At first, she was determined to use Processing to create an interface for her sculpture by recreating the UI visually and adding some touch controls. However, she soon abandoned this tedious task after discovering MacintoshPi, which steps you through installing Mac OS 7, 8, and 9 emulators on a Raspberry Pi. [Joselyn] has also installed several retro games, including DOOM II, Carmen Sandiego, and Sim City, thanks to sites like Macintosh Garden and Macintosh Repository. 

Next, [Joselyn] hopes to set it up to display her and her partner’s schedules, and to let friends play around with nostalgic games. This piece was made using hand building, but other cool ceramic techniques like this slip cast dog bowl and this stone 3D printer have us thinking about what other types of enclosures could be built!

Cut Just About Anything With This Combination Lathe And Wire EDM

July 20, 2022 by 18 Comments

They say that if you have a lathe, you have every other machine tool too. To some degree, that’s true — you can make almost anything on a lathe, including another lathe, and even parts best made on other machine tools can usually be made on a lathe in a pinch. But after seeing this lathe attachment for a DIY electric discharge machining tool, we might be inclined to see the EDM as the one machine tool to rule them all.

Now, we’ll admit that the job [BAXEDM] built this tool for might be a little contrived. He wanted to make some custom hex inserts for his Swiss Army knife, which seem like they’d have been pretty easy to make from hex bar stock in a conventional lathe. Then again, hardened steel is the kind of material that wire EDM was made for, and there seem to be many use cases for an attachment that can spin a workpiece against an EDM cutting wire.

That was really the trick of this build — spinning a part underwater. To accomplish this, [BAXEDM] built a platform to carry a bearing block that supports a standard ER-25 collet, with a bracket that holds a stepper clear of the water in the EDM cutting tank. There are plenty of 3D printed insulators too, to keep most of the attachment electrically isolated from the EDM current, plus exotic parts like ceramic bearings that won’t corrode under water. There were a ton of other considerations, too; [BAXEDM] goes through the long iterative design process in the video below, as well as taking his new tool for a literal spin starting at about the 27:00 mark.

If you’re intrigued by what EDM can accomplish — and who wouldn’t be? — but you need more background on the process, we’ve got you covered.

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