plastic

91 Articles

The Metabolizer Is Turning Trash Into Treasure Even Faster Now

November 5, 2021 by 5 Comments

Do you remember [Sam Smith]’s Metabolizer from a few years back? In case you’ve forgotten, this baby takes trash and turns it into printed plastic objects, and it’s solar-powered to boot. Although the Metabolizer didn’t win the 2018 Hackaday Prize, [Sam] and his machine won many achievements that year, including the Open Hardware Challenge. It’s fantastic to see the project still improving.

To recap, the sun hits the solar panels and charge up the battery bank. Once there’s enough power to start the reaction, it gets dumped into a heating element that turns biomass into biochar. This smoke is cooled, collected, refined, and fed into a small gas generator, which produces DC power to run a 3/4-horsepower shredder and the trash printer.

[Sam] likens this beast to a Rube Goldberg machine in that it performs an overly-complicated chain reaction to do a simple task. We certainly see his point, but we think that this machine is worth so much more than those classic machines, which tend to do nothing useful at all and tend to consume many resources in the process.  On the contrary, the Metabolizer’s chain reaction starts with sunshine and ends with useful objects that keep plastic out of landfills. Honestly, it’s more akin to a compost heap with a PhD in Biology and a handful of steroids and a 3D printer attached.

Unfortunately, [Sam] couldn’t get a prototype working in time for the Prize, and he turned to Patreon to gain support after the $1,000 ran out. Three years and a ton of improvements later, [Sam] has a working prototype that’s cheaper, more efficient, and easier to build. But can it be built relatively easily by someone other than [Sam]? Consider the gauntlet thrown down.

Not happy with your standard-style compost pile? You need a DIY trommel to sift out the bad stuff.

Vacuum Forming With 3D Printed Buck Tutorial

October 22, 2021 by 9 Comments

[Matterhackers] has a nice video tutorial on using vacuum forming to create plastic items. Sure, you have a 3D printer, but vacuum forming has some advantages if you are making thin and flexible items quickly. But don’t feel bad. The master item in the process is from a 3D printer. Like a mold, the forming won’t produce a duplicate of the master, called a buck. Rather, the buck provides something like a die that the plastic wraps around.

While obvious vacuum-formed items include such things as take-out food containers and plastic blister packaging for retail items, you can also make more substantial items. Apparently, all theStar Wars movies in the original trilogy used vacuum forming to create stormtrooper armor.

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A Plastic Injection Machine You Can Use At Home

July 7, 2021 by 25 Comments

3D printing is all well and good if you want one of something, but if you want lots of plastic parts that are all largely identical, you should consider injection molding. You can pay someone to do this for you, or, in true hacker fashion, you can build an entire injection molding setup in your own garage, as [Action BOX] did.

The build relies on a pair of beefy 3hp motors to drive the screw-based injection system. These are responsible for feeding plastic pellets from a hopper and then melting them and filling the injection reservoir, before then forcing the hot plastic into the mold. Further stepper motors handle clamping the mold and then releasing it and ejecting the finished part. A Raspberry Pi handles the operation of the machine, and is configured with a custom Python program that is capable of proper cycle operation. At its peak, the machine can produce up to 4 parts per minute.

It’s an impressive piece of industrial-type hardware. If you want to produce a lot of plastic things in your own facility, a machine like this is very much the way to go. It’s not the first machine of its type we’ve seen, either! Video after the break.  Continue reading “A Plastic Injection Machine You Can Use At Home” →

Discarded Plastic Laser-Cut And Reassembled

July 2, 2021 by 15 Comments

The longevity of plastic is both a blessing and a curse. On the one hand, it’s extremely durable, inexpensive, and easy to work with, but it also doesn’t biodegrade and lasts indefinitely in the environment when not disposed of properly. While this can mean devastating impacts to various ecosystems, it can also be a benefit if you happen to pick this plastic up and also happen to have a laser cutter around.

After cleaning and sorting plastic that they had found from various places, including scraps from a 3D printing facility, the folks at [dinalab] set about turning waste plastic into something that would be usable once more. After sorting it they shredded it and then melted it into sheets. They found that a sandwich press yielded the best results, as it kept the plastic at a low enough temperature to keep it from burning. Once its off of the press and properly cooled, the flat sheets of plastic can be sent to the laser cutter to be made into whatever useful thing they happen to need.

Not only does this process reuse plastic that would otherwise end up in the landfill (or worse, the ocean), it can also reuse plastic from itself since the scraps can be re-melted back into sheets. Plastic does lose some of its favorable material properties with repeated heat cycles, but we’d have to imagine this is negligible for the types of things that [dinalab] is creating. Of course, you can always skip the heat cycles entirely and turn waste plastic directly into 3D printer filament instead.

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Weren’t We Supposed To Live In Plastic Houses In The Future?

April 13, 2021 by 117 Comments

Futurism is dead. At least, the wildly optimistic technology-based futurism of the middle years of the 20th century has been replaced in our version of their future by a much more pessimistic model of environmental challenges and economic woes. No longer will our flying cars take us from our space-age wonder-homes to the monorail which will whisk us through sparkling-clean cities to our robotised workplaces, instead while we may have a global computer network and voice controlled assistants we still live in much the same outdated style as we did decades ago. Our houses are made from wood and bricks by blokes with shovels rather than prefabricated by robots and delivered in minutes, and our furniture would be as familiar to a person from the 1950s as it is for us.

A Plastic Future That Never Quite Happened

There was a time when the future of housing looked remarkably different. Just as today we are busily experimenting with new materials and techniques in the type of stories we feature on Hackaday, in the 1950s there was a fascinating new material for engineers and architects to work with in the form of plastics. The Second World War had spawned a huge industry that needed to be repurposed for peacetime production, so almost everything was considered for the plastic treatment, including houses. It seemed a natural progression that our 21st century houses would be space-age pods rather than the pitched-roof houses inherited from the previous century, so what better way could there be to make them than using the new wonder material? A variety of plastic house designs emerged during that period which remain icons to this day, but here we are five or six decades later and we still don’t live in them. To find out why, it’s worth a look at some of them, partly as a fascinating glimpse of what might have been, but mostly to examine them with the benefit of hindsight.

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Heat Turns 3D Printer Filament Into Springs

January 6, 2021 by 10 Comments

The next time you find yourself in need of some large-ish plastic springs, maybe consider [PattysLab]’s method for making plastic springs out of spare filament. The basic process is simple: tightly wind some 3D printer filament around a steel rod, secure it and wrap it in kapton tape, then heat it up. After cooling, one is left with a reasonably functional spring, apparently with all the advantages of annealed plastic.

The basic process may be simple, but [PattysLab] has a number of tips for getting best results. The first is to use a 3D-printed fixture to help anchor one end of filament to the steel rod, then use the help of an electric drill to wind the filament tightly. After wrapping the plastic with kapton tape (wrap counter to the direction of the spring winding, so that peeling the tape later doesn’t pull the spring apart), he suspends it in a pre-heated oven at 120 C for PLA and 160 C for PETG. How long does it stay in there? [PattysLab] uses the following method: when the spring is wound, he leaves a couple inches of filament sticking out to act as a visual indicator. When this segment of filament sags down, that’s his cue to begin the retrieval process. After cooling, the result is a compression or extension spring, depending on how it was wound before being heated.

[PattysLab] shared a short video on this Reddit post that shows both springs in action, and the process is all covered in the video, embedded below.

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DIY Injection Molding Press

January 1, 2021 by 24 Comments

While 3D printing has now become easily accessible and cheap, there are still several use cases where you need the advantages offered by injection molding, even for small batch runs. Professional small-batch injection molding can be pretty expensive, and buying a manual machine can cost quite a bit. Of course, there are a number of DIY injection molding projects to choose from, but they usually involve a fair amount of tools and labour. [Bolzbrain] wanted to bypass all of the heavy cutting, welding and frame assembly work, so he’s built himself a DIY Injection Molding Press for cheap using an off the shelf, six ton hydraulic press. At final count, he ended up spending about €150 for the machine and another €120 for tools to build the machine. He also managed to locate a cheap, local CNC service that gave him a good deal on machining the Dies. But of course you can’t put a price on the lessons learnt and the satisfaction of having built it by hand.

Choosing the hydraulic press is a great idea as it provides the high pressure needed for the job without the operator having to exert a lot of effort, which is a big drawback with some of the other DIY machines. As a bonus, the structural frame is quite sturdy and well suited for this purpose. The other main part of such a machine is the heated injection block and there are several different ways of doing it. After some amount of studying probable solutions, he decided to build a heated aluminium block through which the plastic granules can be rammed using the hydraulic piston. Heating is provided by a pair of 500W heaters and a type ‘k’ thermocouple does temperature sensing. An industrial PID controller adjusts the block temperature via a solid state relay. Overall, the electrical and mechanical layout cannot get any simpler.

[Bolzbrain] did a great job of documenting his build over a series of videos and more wizened hackers watching them will squirm in their seats spotting the numerous fails. He bought the cheapest pedestal drill machine that he could buy and watching the drill struggle while making a 26mm hole in the aluminium block is quite jarring.

The electrical wiring has a lot of scope for improvement – with 220V AC heaters, exposed wiring and jury rigged panel held up with a pair of clamps. Installing and removing the die is a task and requires a lot of fiddling with several C-clamps — something which needs to be repeated for every shot. Maybe toggle clamps could help him to ease die fixing and removal. Once he figures out about mold release agents and wall draft angles, he won’t have to struggle trying to remove the molded article from the die. Then there’s the issue of proper runner design so that the thermo-plastic can quickly fill the mold cavity completely without any pockets.

But in the end, all that matters is that he is getting reasonably good molded parts for his purposes. With more tweaking and incremental improvements, we’re sure he’ll get better results. The video after the break is a short overview of his build, but the project page has a series of detailed videos covering all aspects of the project. And if you’d like to get an introduction to desktop injection molding, check out “Benchtop Injection Molding for the Home Gamer”

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