Repairing Broken Injection Molded Parts With A 3D Printer

injection-molded-part-repair

The value of a 3D printer is obvious for people who hack hardware as a hobby. But this repair project should drive home their usefulness for the commoner. [James Bruton] used a 3D printer to recreate a hopelessly broken injection molded plastic part. This is a suction cup mounting bracket for a Tom Tom GPS module. The sphere which makes it adjustable had broken off of the column holding it. For 100% of non-hacking consumers that’s the end of this item. We can’t see a fix that would restore the strength of the original part.

The replacement starts by measuring the broken part with precision calipers. [James] then grabbed a copy of 123D, which is free software. He starts by modeling the sphere, then builds up the support column and the base with a cut-out. It’s obvious he’s already very familiar with the software, but even the uninitiated should be able to get this done pretty quickly. After slicing the design for the 3D printer he finds the part will be ready in about 11 minutes. The first prototype is a bit too small (the ball requires close tolerances to work well). He spins up a second version which is a bit large and uneven. A few minutes of filing leaves him with a smooth sphere which replaces the original part beautifully!

You can see the entire design, print, and assembly process in the clip after the break.

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Cloud Support For Fleets Of 3D Printers

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More than ever, 3D printers are being used for small prototype and production runs, and the normal way of using a 3D printer with a single desktop app is becoming more and more out of date. [Zach ‘Hoeken’ Smith] has a solution to the frustration of printing out multiples of objects: it’s called BotQueue, and allows anyone to submit print jobs to multiple 3D printers over the Internet.

The idea behind BotQueue is to allow anyone to send jobs to a 3D printer over the Internet. Queues and multiple printers are supported, meaning small-scale manufacturing just got a lot easier for anyone dealing with multiple printers.

We’ve seen a few 3D printer fleets that could benefit from an online print server for multiple 3D printers. It’s not a project meant for everyone – one 3D printer per person should be enough for just about everybody – but if you’re part of a hackerspace with a few printers, we could see this being used to great effect among your fellow makers. You’re not limited to using the official BotQueue servers, either. You can run your own BotQueue from [Zach]’s git

DEFCAD, The Island Of Misfit Objects

Defense Distributed, the guys working on 3D printed guns and lower receivers for an AR-15, have a storied history with makers, corporations, and our elected representatives. When the news broke they were designing a 3D printed weapon, their $25,000 leased 3D printer was taken away from them. When their designs were too controversial for Thingiverse, they were taken down. Defense Distributed keeps on firing back, though, and now they’re hosting their own 3D model repo called DEFCAD.

In another one of Defense Distributed’s well-produced promo videos, they make their case for a repository of 3D models that doesn’t respond to takedown requests. Basically, 3D printing is a disruptive technology and is too important to be beholden to copyright lawyers, talking heads of the media, and, “the collusive members of the maker community”.

DEFCAD isn’t only about guns. They plan on hosting anything those in the upper echelons of power don’t like – or at least those with a copyright, patent, or trademark gripe – and never responding to a takedown request. It’s a great idea, somewhat akin to The Pirate Bay for physical objects, but actually popular.

Molding Rubber For A Pre-production Prototype Using A 3D Printed Model

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When you’re getting close to a production run the prototypes really need to hit the mark before pulling the trigger. [Bob’s] still hard at work getting his scoreboard off the ground and his most recent endeavor was to find a way to prototype the rubber gasket without blowing his shoestring budget. His solution was to harness the power of 3D printing to generate a model from which he could create the mold from which he cast the rubber part.

To make things a bit more difficult, the band isn’t just decorative, it doubles as the tactile part of the scoreboard buttons. You can see all six of them (before being painted to make them stand out) in the inset image above. Just above that image is a picture of the mold making process. The toothpicks are suspending the 3D printed model of the rubber band while the lower half of the silicone mold sets up. Once that had happened [Bob] sprayed release agent to ensure the top half of the mold wouldn’t stick while it cured.

The results turned out just great. Sure, this isn’t the way to go if you’re making a lot of these things. But we’re impressed at the quality he achieve for a one-off item.

If the finished product on the left looks familiar it’s because we looked in on the project last June. [Bob] continues with improvements and plans to launch a crowd funding campaign this week.

One Piece, 3D Printed Crossbow

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Centuries ago, craftsmen and smiths of all sort spent hundreds of hours crafting a crossbow. From the fine craftsmanship that went into making the bow to the impeccable smithing a windlass requires, a lot of effort went into building a machine of war. Since [Chris] has a 3D printer, he figured he could do just as well as these long-dead craftsmen and fabricate a crossbow in under a day.

What’s really interesting about [Chris]’ crossbow is that it is only a single piece of plastic. The bow is integrated into the stock, and the trigger works by some creative CAD design that takes advantage of the bendability of plastic. The only thing required to shoot a bolt from this crossbow is a piece of string. That, and a few chopsticks.

He won’t be taking part in any sieges, but [Chris]’ weapon is more than capable of shooting a bolt across a room or launching a balsa wood airplane. You can see an example of this after the break.

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Makerbot Shows Off 3D Scanner

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We’ve said our piece over Makerbot and their interpretation of what Open Source means, but the fact remains if you’re sourcing a 3D printer for a high school shop class or a hackerspace, you really can’t do much better than a Makerbot Replicator. Apparently Makerbot is looking to expand their 3D design and fabrication portfolio; they just announced an upcoming 3D scanner at SXSW. It’s called the Makerbot Digitizer, and it takes real, 3D objects and turns them into CAD files.

Since Makerbot and [Bre Pettis] didn’t give out much information about the 3D scanner they’re working on, the best information comes from Techcrunch. The Makerbot Digitizer uses two lasers to scan real objects and turns them into 3D CAD files. The hardware isn’t finalized, and the prototype is made of a few pieces of laser cut plywood. No details are available on how much the Digitizer will cost, when it will be available, or what its resolution is.

Of course 3D scanning of real objects to translate them into CAD files is nothing new for Hackaday readers. We’ve seen our fair share of desktop 3D scanners, including one that was built in a day out of junk. Even the Kickstarter crew has gotten into the action with a few desktop 3D scanners, some of which scan in full color.

Fabricating Edible LEDs

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They’re edible, yes. But they don’t light up. That’s fine with us, since the process [Becky Stern] used to make these gummy candy LEDs taps into several techniques handy to have under your belt.

The first part shown in her video (embedded after the jump) is to make a mold for the candies. You probably have a few bags of LEDs in your parts bin. Those along with a trough made of foam core come together to create the form for the silicone mold. After mixing, pouring, and hardening, [Becky] peels the silicone off of the LEDs and sends it through the oven to make it food-safe. Mixing up the candy uses simple ingredients (gelatin, water, and ascorbic acid) but you’ll need to follow the methodology closely to get the taste and clarity you’re used to. Syringes are used to fill the tiny voids in the mold before adding leads which were 3D printed using PLA.

These will be a huge hit at your next hackerspace meeting!

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