Benchtop Injection Molding For The Home Gamer

October 16, 2020 by Lewin Day 8 Comments

When we think injection molding, the first thing that comes to mind is highly automated production lines pumping out thousands of parts an hour. However, the very same techniques are able to be scaled down to a level accessible by the DIYer, as [The CrafsMan] demonstrates.

Using a compact, hand-actuated injection moulder, [The Crafsman] demonstrates the basic techniques behind small-scale injection molding. The PIM-Shooter Model 150A in question is designed to work with low melting point plastics like polypropylene and low density polyethylene, and can use aluminium molds which are much cheaper to make than the typical steel molds used in industry.

However, the real game changer is when [The Crafsman] busts out his silicone mold making techniques, and applies them to injection molding. By making molds out of silicone, they can be created far more cheaply and easily without the requirement of heavy CNC machinery to produce the required geometry. With the right attention to detail, it’s possible to get good results without having to invest in a custom aluminium mold at all.

Injection molding is a process that can achieve things 3D printing and other techniques simply can’t; it can even be used to produce viable lenses. Video after the break.

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An Impressive Modular Mold Box

October 7, 2020 by Kristina Panos 26 Comments

Prolific maker and product designer [Eric Strebel] has years of experience making reusable mold boxes for silicone and resin casting. He’s always used 3/4″ plywood before, but it comes with some problems such as inaccuracy, screws that eventually slip out, and no room at all for expansion. Now [Eric] has decided to devise a modular mold box system that’s so awesome, it’s even stack-able. Check out the design and build process in the video after the break.

[Eric] took advantage of additive manufacturing and made fancy trapezoidal walls with recessed bits that allow for the magic that this modular system hinges on — a handful of M6 socket cap screws and matching nuts for tensioning. Once the prints were ready, [Eric] pounded the nuts captive into the walls and marked fill lines every 10mm. As usual, [Eric]’s video comes with bonus nuggets of knowledge, like his use of a simple card scraper to clean up prints, smooth the sides, and chamfer all the edges.

If you want to mold stuff like concrete and plaster, you may be better off using flexible filament.

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Mold-Making Masterclass In Minutes

August 5, 2020 by Kristina Panos 11 Comments

Making silicone molds seems easy, but there are a lot of missteps to be made along the way that can mean the difference between a great, reusable mold, and one that’s a sad waste of silicone. If you’re helpless to know the difference, then check out [Eric Strebel]’s 9-minute masterclass teaser video on making a two-part mold for resin casting, which is also embedded below.

Even if you already know how to do this, there’s probably a good tip in here somewhere. One of them being that you should always pour your silicone from one place and let it coat the piece being copied. Otherwise, there might be lines on the mold. Another tip is for DIY mold release made from petroleum jelly thinned with naphtha.

Our favorite tip has to do with the way [Eric] makes this a reusable two-part mold, which is more akin to injection molding. To pour silicone for the second part and get it to separately nicely, [Eric] uses sprues made out of resin rods that were cast inside of drinking straw molds. These he chamfers against a belt sander to minimize the contact with the cast part, which makes them a snap to break off. [Eric] says this is just the beginning, and there are more videos to come that will break down the steps.

There’s more than one way to make a mold, especially for casting in metal. We’ve seen everything from 3D-printed molds to kinetic sand.

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Gain An Understanding Of Injection Molding’s Design Gotchas

April 19, 2020 by Donald Papp 11 Comments

When it comes to manufacturing, sheet metal and injection molding make the world go ’round. As a manufacturing method, injection molding has its own range of unique design issues and gotchas that are better to be aware of than not. To help with this awareness, [studiored] has a series of blog posts describing injection molding design issues, presented from the perspective of how to avoid and address them.

Design of screw bosses demonstrating conflict between molder’s guidelines and vendor’s recommendations. Compromising between both is a science and an art.

Because injection molding involves heat, warp is one issue to be aware of and its principles will probably be familiar to anyone with nitty-gritty experience in 3D printing. Sink marks are also an issue that comes down to differential cooling causing problems, and can ruin a smooth and glossy finish. Both of these play a role in how best to design bosses.

Minimizing and simplifying undercuts (similar to overhangs in 3D printer parlance) is a bit more in-depth, because even a single undercut means much more complex tooling for the mold. Finally, because injection molding depends on reliably molding, cooling, and ejecting parts, designing parts with draft (a slight angle to aid part removal) can be a fact of life.

[studiored] seems to have been working overtime on sharing tips for product design and manufacture on their blog, so it’s worth keeping an eye on it for more additions. We mentioned earlier that much of the manufacturing world revolves around injection molding and sheet metal, so to round out your knowledge we published a primer on everything you need to know about the art and science of bending sheet metal. With a working knowledge of the kinds of design issues that affect these two common manufacturing methods, you’ll have a solid foundation for any forays into either world.

3D Printing Fishing Lure Molds

April 10, 2020 by Al Williams 7 Comments

Every fisherman has a secret. A secret spot, a secret technique, or a secret bait. Maybe that’s why tying flies is so popular. [Steve] certainly has is own special lures, although he’s not keeping it a secret. (Video, embedded below.) He designs lures in Simplify3D, 3D prints molds, and then casts them.

The 3D printing part is interesting, but it is also kind of neat to see the lures and the natural prey he uses for inspiration. If you want to catch fish, you have to use bait that looks like real food.

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Acrylic Mold Makes For Professional-Looking Silicone Keyboards

February 3, 2020 by Dan Maloney 17 Comments

The border between consumer electronics and DIY projects is getting harder and harder to define. First it was PCBs, which quickly went from homemade to professional with quick-turn services. Then low-cost CAD/CAM packages and high-end fabrication services gave us access to enclosures that were more than black plastic boxes with aluminum covers. Where will it end?

That’s a question [arturo182] begins to answer with this custom-molded silicone keyboard for a handheld device. There’s no formal writeup, but the Twitter thread goes into some detail about the process he used to make the tiny qwerty keypad. The build started by milling a two-part mold from acrylic. Silicone rubber was tinted and degassed before injecting into the mold with a baster. The keys are connected by a thin membrane of silicone, and each has a small nub on the back for actuating a switch.

There’s clearly room for improvement in this proof of concept – tool marks from the milling process mar the finish of the keys slightly, for instance. There may be tips to be had from this article on silicone keyboard refurbishment to improve the process, but overall, we’d say [arturo182] is well on his way here.

Hackaday Podcast 038: Cyberdecks Taking Over, Resin 3D-Printing Vs FDM, Silicone Injection Molding, And The Pickle Fork Fiasco

October 4, 2019 by Mike Szczys 4 Comments

Hackaday Editors Tom Nardi and Mike Szczys comb through their favorite hacks from the past week. We loved Donald Papp’s article on considerations before making the leap from FDM 3D Printers to a resin-based process, and we solidify our thoughts on curing cement in low-gravity. Tom’s working on a Cyberdeck build, and he also found an ancient episode of an earlier and much different version of the Hackaday podcast. We’re impressed with a mostly 3D-printed useless machine, a thermal-insert press that’s also 3D-printed, and the Raspberry-Pi based Sidekick clone that popped up this week. A DIY wire-bending robot is an incredible build, as is the gorgeous wire-routing in a mechanical keyboard, and the filigree work on this playing card press. Plus you need to spend some time getting lost in this one hydrogen-line telescope project.

Take a look at the links below if you want to follow along, and as always tell us what you think about this episode in the comments!

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct download (60 MB or so.)