lost wax

3 Articles

Creating A Custom Engagement Ring With 3D-Printing

January 5, 2020 by 11 Comments

Even if you’re pretty sure what the answer will be, a marriage proposal is attended by a great deal of stress to make the event as memorable and romantic as possible. You’ve got a lot of details to look after, not least of which is the ring. So why not take some of the pressure off and just 3D-print the thing?

No, a cheesy PLA ring is probably not going to cut it with even the most understanding of fiancees, and that’s not at all what [Justin Lam] did with this DIY engagement ring. He took an engineer’s approach to the problem – gathering specs, making iterative design changes in Fusion 360, and having a prototype ring SLA printed by a friend. That allowed him to tweak the design before sending it off to Shapeways for production. We were surprised to learn that jewelry printing is a big deal, and Shapeways uses a lost-wax process for it. First a high-resolution wax SLA printer is used to make a detailed positive, which is then used to make a plaster mold. The mold is fired to melt the wax, and molten gold is poured in to make the rough casting, which is cleaned and polished before shipping.

Once he had the ring, [Justin] watched a few jewelry-making videos to learn how to set the family heirloom stone into the bezel setting; we admit we cringed a bit when he said he used the blade shaft of a screwdriver to crimp the edge of the bezel to the stone. But it came out great, even if it needed a bit of resizing. The details of the proposal are left to the romantically inclined, but TL;DR – she said yes.

Congratulations to the happy couple, and to [Justin] for pulling off a beautiful build. Most of our jewelry hacks are of the blinkenlight variety rather than fine jewelry, although we have featured a machinist’s take on the subject before.

Lost PLA Casting With A Little Help From Your Microwave

August 20, 2014 by 45 Comments

lost-pla

[Julia and Mason] have been perfecting their microwave-based lost PLA casting technique over at Hackaday.io. As the name implies, lost PLA is similar to lost wax casting techniques. We’ve covered lost PLA before, but it always involved forges. [Julia and Mason] have moved the entire process over to a pair of microwaves.

Building on the work of the FOSScar project, the pair needed a way to burn the PLA out of a mold with a microwave. The trick is to use a susceptor. Susceptors convert the microwave’s RF energy into thermal energy exactly where it is needed. If you’ve ever nuked a hot pocket, the crisping sleeve is lined with susceptor material. After trying several materials, [Julia and Mason] settled on a mixture of silicon carbide, sugar, water, and alcohol for their susceptor.

The actual technique is pretty simple. A part printed in PLA is coated with susceptor. The part is then placed in a mold made of plaster of paris and perlite. The entire mold is cooked in an unmodified household microwave to burn out the PLA.

A second microwave with a top emitter is used to melt down aluminum, which is then poured into the prepared mold. When the metal cools, the mold is broken away to reveal a part ready to be machined.

We think this is a heck of a lot of work for a single part. Sometimes you really need a metal piece, though. Until metal 3D printing becomes cheap enough for everyone to do at home, this will work pretty well.

How A Maker Proposes

June 6, 2014 by 30 Comments

proposal

[Sefi Attias] just sent us a heartwarming little video of how he proposed to his girlfriend [Tania] — using a little help from technology and other makers.

As a maker, [Sefi] was always building things which impressed [Tania], so he thought it was only fitting to make the proposal a one-of-a-kind maker experience.

He started by designing the engagement ring himself, to be 3D printed. It’s an amazingly complex little thing made up of the repeating words of the quote “I will betroth you to me forever”. It was almost too complex in order to print — but they managed to do it in wax, which allowed them to create a mold and then cast the final part in white gold. Once complete, they set a diamond in place to cap it all off.

The second step was the proposal, which was made possible using a quadrotor, a strip of RGB LEDs, and a long camera exposure. To show it off in real-time to [Tania] they setup a projector and screen on the side of the street, providing a surreal window into the park behind them. It was all made possible with the help from over 20 people from the XLN Makerspace and SkyLens (the quadrotor people).

Oh yeah, and she said yes.

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