Plastic Recycling At Home Promises A Revolution In Local Plastic Production

[Dave Hakkens] graduated from the Design Academy of Eindhoven and decided to try his hand at making affordable plastic recycling machines.

His reasoning?

“We recycle just 10% [of waste plastic],” says Hakkens. “I wondered why we recycle so little so I investigated it. I went to all these companies and I realized that they don’t really want to use recycled plastic. So I wanted to make my own tools so I could use recycled plastic locally.”

Typical plastic production, like injection molding, uses very large and expensive machines — so expensive that most of the time, companies don’t want to risk using inferior recycled plastic, as it might damage the machine, or slow production time. Not convinced that recycled plastic is “inferior”, [Dave] has built his own line of machines capable of making recycled plastic parts.

He’s built his own rotary molder, a lever-operated injection molding machine, an extruder, and even a plastic shredder capable of taking in most scrap plastic. The results are quite impressive, and the machines are relatively simple to build. He’s also decided to make the project open source to encourage others to help save the environment — He hasn’t released the plans online just yet, but promises they will come soon! To see the machines in action, and to see what they’re capable of, check out the following video:

Did Eindhoven ring any bells? Hack a Day actually visited Eindhoven during our Hackerspacing in Europe tour! We visited the city, the old factories, the university, and a children’s hackerspace called the De Ontdekfabriek!

72 thoughts on “Plastic Recycling At Home Promises A Revolution In Local Plastic Production

  1. I’m impressed. But it’s only half the equation, now [Dave] just needs an actual product. Preferably something:

    1) With wide enough appeal that you can move a lot of recycled plastic.
    2) That won’t itself be quickly thrown away.
    3) If similar to a product that already exists, can be produced at a reasonably competitive price; else you limit yourself to a niche market of hardcore environmentalist customers, and come into conflict with #1.

    And that’s where reality typically bites you on the arse.

      1. That’s a good idea. Although I understand a lot of plastics used in things intended to be disposable nowadays have something added to them which makes them brittle with sunlight exposure, so they eventually degrade into small chunks. And I’m sure they lack UV inhibitors as well. You’d have to keep the product out of the sun for a long life, or keep it painted. Assuming it will reliably take paint. You never really know what properties a recycled piece of plastic will impart to your product.

        1. Yeah it wouldn’t work. The reason composite lumber is so expensive is due to the carefully formulated plastic they use. It has properties that make it resistant to sunlight and heat/pressure changes that believe it or not are NOT normally associated with plastic.

          Plastic may not break down into safe elements easily but even untreated plastic gets extremely brittle in sunlight and doesn’t respond well to temperature changes. This is why on pvc pipe it’s printed to keep it out of direct sunlight. Within a year it becomes brittle to the touch, much less structurally sound.

          1. Maybe something like long term storage boxes, or semi-personalised house moving boxes? Everything can be recycled again and stays out of weather, plus a crate or drawer is a simple and cheap form to make.

      1. Not here in Australia.
        Youtube works flawlessly, Vimeo almost never even loads. Even when it does, is stops and buffers all the time. Unless you want to walk away and make a coffee while it loads first, Vimeo is useless.

  2. I think it’s a great idea BUT…

    He didn’t create anything that proves the homemade plastic he’s creating is as strong/durable as commercial grade plastic items.

    Also I’m sure the hipsters like the swirl coloring, but making things in solid colors would probably be a good idea as well.

    I like the injection molder …that would probably be the only viable one.

    But he kind of skirts over the issue that injection molds have to be cnc machined and they can cost hundreds or thousands of dollars to get made. The project isn’t nearly as cheap or easy as he’s alluding to.

      1. most? really?
        will your trashcan disintegrate because its made of recycled trash?
        how about hmmm, hell 90% of crap around me doesnt care and could be made out of bakelite (and probably was before I was born judging by that great bakelite vid yesterday on hackaday)

        Its not like every pencil, pin or cup holder needs to have magical super strong yet flexible properties

        1. I think the point Tyler was trying to make is: every time you remelt plastic volatile parts get driven off, or burnt. This changes the properties not only of the final product but also of the intermediate, which greatly impacts the characteristics of the plastic you are molding.
          Companies spend billions of dollars annually on quality control and if you don’t know the characteristics of your raw materials it is next to impossible to meet your production quotas. Production lines are optimized for a very narrow window of mechanical characteristics and if the transition temperatures are off, or the viscosity changes your trashcan won’t come off the line looking like a trashcan.

          That’s not to say we shouldn’t follow this line of research, just that it misses some critical factors.

        2. Bakelite, like Melamine, are thermoset plastics and can not be remelted

          Theremplastics, like polypropylene, ABS, and Nylon, can be reprocessed. Most of the time we do regrind runners and scrapped parts, though some customers specify only virgin material is to be used. Other jobs all 100% reprocessed material.

          As for mixing plastics, you have to be very careful. Each plastic has a very specific working temperature range. Polypropylene typically runs at 390F, ABS in the 400’s and Nylons, LCP, and polycarbonates in the 500’s. If you mix PP with Nylon you will create lots of smoke. That is considered bad.

          Note ABS is a blend of acrylonitrile, butadiene, and styrene (hence it’s name). But it not quite as simple as just mixing the three.

        1. Well if we are going there….

          Other than for one-off art projects, diy fixes or rapid prototyping, 3d printing is fairly useless.

          The end product is usually relatively brittle, crudely formed, not within machine spec tolerances, and not cost-effective at all.

          I know that 3d printing is a neat toy, but it’s just that. It isn’t practical at all for industrial applications specifically due to the concept of re-heating pre-molded plastic. Compare it to it’s step-brother cnc milling and the resulting end product is inferior in almost every way.

          1. What a load of crap. First of all it’s not brittle. The ABS my machine extrudes is incredibly strong. Yes a CNC setup can produce a nicer finish in more typical industrial materials, but once 3D printer tech gets far enough ahead CNC machines will be a thing of the past. We may be talking 20,50 or even 200 years in the future, but it is going to happen sooner or later :)

          2. Hey you! Stop pointing out inconvenient facts!

            I’m still confused that everyone seems to be heralding 3D printing as some amazing game-changer, but you can buy a used mill (or lathe) and CNC it for less than the price of most 3D printers, and produce solid items from wood, metal, plastic, wax etc. that are actually usable, are much stronger and more stable, with a better finish and dimensionally accurate.

            Also, as Elrinn’s misguided post shows, people are also ignoring the fact that different production methods are suited to different VOLUMES of the same thing – need 1 of something, 3D print it. Need 10,000, then injection mold it.

          3. Eirinn:
            Why do you say, and more importantly, want, 3d printing to replace milling in 20 or 200 years? Is there some advantage? As 3d printing technology advances, so will milling technology. Is this just some fetishistic desire to produce a product by just pressing print, or is there more to it than that?

          4. Also, why do people keep comparing additive manufacturing techniques with subtractive?
            They clearly have different capability’s in what they can make.

            Can CNC machines make working whistles? (pretty much the most basic/first thing 3D Printer uses make) ?

            I made a complete box, with working hinged lid…it comes straight of the printer with no post-work needed. Can a cnc machine do that?

            The idea that one is “better” is just silly. They are suited for different things. The USP of 3d printers is, for the least effort, they can make the broadest array of things.
            Not “best”, not “cheapest” but “easiest and most flexible”.
            Exactly like 2D Printers really. They arnt useless just because you don’t print novels or newspapers with them.

          5. HowardC wrote: Other than for one-off art projects, diy fixes or rapid prototyping, 3d printing is fairly useless.

            One off art projects – good use!
            DIY fixes – great use!
            Rapid Prototyping – great use!

            Across those categories is the ability to send data files of those products around the globe for one-off use elsewhere. (Yes, those capabilities exist for CNC files as well)

            So let’s not throw the baby out with the bath water!

  3. There are two main types of plastics, thermoplastics which can be re-melted and thermoset plastics which can’t be re-melted. Thermosets can be ground up and used as filler material. Generally classed with thermosets are plastics that are chemically catalyzed due to self generated heat aiding their reactions which change them from liquid to solid.

    There’s a huge variety of types of plastics, far more than what those triangle arrow symbols indicate. Minor tweaks in the chemistry can greatly alter the properties. Some just won’t mix together, even when finely ground and melted together, they either won’t bond or bond weakly.

    Every thermoplastic degrades some each time its melted. Some can come close to their original properties the second time while others are badly degraded after a second melting. Mixing in some ‘virgin’ plastic of the same type can get recycled plastic quite close to once melted properties.

    Then there’s the contamination problem. Plastic from chemical containers (including soaps and detergents) cannot be re-used to make anything that will be used in direct contact with food. Washing the plastic after grinding doesn’t remove all the contamination and is expensive in water use/contamination and the need to dry the grindings before melting.

    Yet another problem is that many plastic items are no longer one homogenous chunk of the same type of plastic. They can be made of several types molded side by side or layered over one another or have a thermoset core with various thermoplastics overmolded.

    Even the everyday soda bottle is now a multi-layer sandwich with various plastics used to provide various properties of strength, gas barrier, color etc, often with a core layer of partly recycled PET, which used to comprise the entire bottle when the plastic soda bottle first hit the shelves.

    1. A good analysis.
      So the rules are:
      1: know your basic plastic chemestry
      2: don’t mix types
      3: never eat or drink from it
      4: never expect properties necessary for human safety, such as strength or durability

    2. I agree with everything you said except for the soda bottle. I am a maintenance engineer where they make polyester and drink bottle “plugs” (which is the entire bottle before it is blown into its final decorative shape). They are made from virgin PET, for the reasons you mentioned above (coming in contact with food, etc.). Other than the cap and label, everything is PET.

  4. OK,
    Was anyone else thinking that this was an Inception moment while watching the top?

    This has been an interest area of mine since I decided to get a 3D printer. I don’t want to be part of the problem.
    There are several issues in recycling that need to be addressed.
    1. Identify the plastic, Not just by the label but by the properties. (Found some sites to help with flame, density, and chemical properties to identify plastics.)
    2. Clean the plastic
    3. Get a good shred of the plastic (Intrigued by the shredder he was using. I’ve been thinking about a chipper/shredder type machine.)
    4. Mix with some new plastic.(beads are cheaper than filament.)
    5. Keep the melt temperature as low as possible.
    6. Identify what is lost when remelting. Is it polymer cross-links that are broken, heat degradation products that are produced or additives to the plastic that are lost when re-melting?

    1. “Beads are cheaper than filament”

      Sorry, kind of off topic but why exactly is that?

      The reason I ask is that most beads I have seen are actually shaped as smooth cylinders with pinched ends. It’s exactly what I would expect to see if they started out as fillament and were run through a machine that chops them up into little pieces. Is that how beads are made? If so then for 3d printing use people are buying filament which has been chopped into beads just to remelt it back into filament? How inefficient! is it just a difference of companies taking a higher profit margin on spooled filament vs filament that has been chopped up into beads?

      1. I’m not in the plastics industry, but my theory would be that:
        1. Filament needs to be smooth and continuous with no air inclusions
        2. Filament diameter needs to be within a certain tolerance.
        3. Filament has to be shipped and stored on spools, (would knot be good if left loose)
        4. Beads are used in injection molding, therefore most common form.
        5. Beads are more space efficient to store, easier to measure out by pound.and easier to blend with other colors.
        6. Beads are easier to handle after forming. Long filament would need to be cooled and straightened before spooling.

  5. You know, remelting plastic doesn’t even need to actually make anything useful, if we can use it to compact the broken plastic parts into chunks which fit well together and then store them underground or incinerate them, we are at least reducing environment saturation by it. Look up “Great Pacific garbage patch” – all of the loose plastic particles and parts eventually end up in oceans’ gyres – places encircled by main ocean currents. I tend to be reluctant to dispose of common thin sheet plastic bags, because a small mass of those can make a big mess in tree branches and waterways when strong winds blow over garbage dump sites. If I could remelt those bags into solid bricks, that would be much better. And then, if there was anything useful to be done with all that plastic, that would be even better, but for start just compacting it is step in right direction.

    1. I agree with this- seems like bricks of even extremely low quality plastic would be strong and useful for something and if not, stack them up somewhere at least they’re compact. Eventually couldn’t they be re-refined into their component chemicals? A mixed plastic chuck can’t be separated into types through some sort of refining process? Does that take too much energy or something?

    2. About 20 years ago, at a Recycling exhibition in Boulder, Colorado, one of the exhibitors showed various plastics he’d shredded, melted and extruded. A brownish gray rod caught my attention. It was about an inch in diameter and fairly strong (I couldn’t have broke it by bending it with between my hands). He told me it was made of used disposable diapers! (Ugh! but the heat had sterilized them) Anyway, my point (and his) was re-using plastics for mundane uses, such as parking lot wheel stops. I could imagine those “diaper rods” being used for livestock fencing.

    3. I’m not so sure about that. How much energy does it take to melt that plastic? How much air pollution does it produce? Might compacting without melting achieve close to the same benefit space-wise while using less energy and creating less pollution? How about shredding? Small shredded pieces could settle into a smaller vollume even without the effort of compacting.

      And, you mentioned incineration. If you are going to incinerate it why expend the energy to melt it first? Then again, maybe the heat produced incinerating one batch could be used to melt the next. Better yet, don’t. Use that heat for something else like generating electricity or even just to heat water to run through pipes under the road melting winter ice.

    4. That has nothing to do with the actual design of the plastic, it ends up in the sea when you just dump it on hills or dump it in the sea. Where other countries burn it and use the energy for something. It’s a choice not a necessity and it is unrelated to it being shredded.

    5. I’ve napkin-sketched a large-scale 3d printer based upon something like this.. the idea being that low-grade plastic is melted and used as a binder for sand.. the printer’s job is to 3d-print shelters of the conglomerate. As it is a plastic and not a concrete, curing time is very short and such a device could provide shelter, as long as you have trash (or pellets) and clean sand you have building material.

      The sketch design is a 3 or 4-point suspension head.

    1. Expanded foam is mostly air. You have to haul a large volume of scrap, but get relatively little material out of it.

      Most of the stuff you throw away is greasy take-out containers. Nobody wants to sort that stuff for recycling, and the recyclers don’t want to deal with it, either.

    2. To expand on what ChalkBored said, recycling is a business. Recycling isn’t altruistic, and if there isn’t consistent profit to be made it’s going into the landfill. You’d be surprised what percentage of the stuff you put into your recycle bin ends up not being recycled.

    3. Foam makes great fire starter if you dissolve it in gasoline. Get a gallon paint can, put in about a pint of gas. Stuff in the foam. Keep stuffing it in until it turns into a gooey mass. You can keep adding fresh foam as it will still slowly dissolve.

      When you want to start a fire, grab a branch an inch or two thick, and wrap the stuff around it like a candy cane. Pile on the rest of your wood, light it, and wait. It’ll burn for about 15-20 minutes and get your fire going.

        1. Polystyrene and fuel is Napalm B. The original formulation was different. In order to weaponize Napalm B you have to add an initiator to it. Thermite works well. Just trying to help.

    4. Well, in the current world climate you can recycle it into molotov cocktail components I guess.
      And of course into insulation, and in poor but cold places that would be welcome I’m guessing.

  6. Think bricks. Lego like bricks or components like Ikea.
    Block UV? paint it.
    It seems like with a shredder and a caulk gun with serious heating element, I could build plastic bricks. Standard architectural bricks aren’t a marvel of engineering. Build a mold, pour the stuff in, let it harden. Obviously, one shouldn’t build a 12 story building with it, but I could build a substantial garden shedlike critter with “free” stuff by building solid interlocking bricks.

    I think we need to think here about how much time & energy it would take produce another usable product from the techniques demonstrated here. This tech reminds me of how automagic saws developed. Ever see a chainsaw from the ’20s?

    This article actually supports the premise of distributed recycling as well as the promise of altering the centric system of manufacturing we have now. Think – what if your local grocer could just build a bottle for the amount of something you wanted? Packaging as we know it could go away for many bulk use items.

    If we can make it cheaper to produce an object locally than to build it and transport it, you’ve got something very valuable. Worst case, sail it out to
    and build bricks…

    1. Instead of bricks, make 4×8 panels of various thicknesses. Those could be used for building materials in refugee camps. Or I think one crowd funded idea was to injection mold stackable emergency shelters with (stackable) snap-on floors and doors.

  7. Is the idea for everyone to start doing this themselves?

    I have the same concern about this as I do about the idea that people’s home 3d printers will replace a significant portion of industrial manufacturing.

    It’s great to have the ability to produce a few things yourself now and then. If we re-used all of our plastic and made everything ourselves how much pollution would we produce? I don’t think most of us can afford to put in place all the pollution controls and smoke stack scrubbers that a real factory has. We aren’t all going to get regular inspections by the EPA (or our respective contry’s equivalents). I would think before long we would all have emphazima, lung cancer and our homes would be uninhabittable!

    I also wouldn’t think the process would be anywhere near as energy efficient with all of us running personal sized manufacturing equipment vs factories running big machines pushing out millions of items per day.

    Don’t get me wrong, I love DIY. I love the idea of everyone everywhere being capable of making anything. However, I do think there is an important distinction to be made between making anything and making everything.

    1. He shreds then melts, what are you taking about with your smoke stacks and EPA stuff? It’s already EPA approved when they made the original bottles, and as long as you don’t burn it there is no significant impact except for the energy used to shred and melt.
      But with the ever increasing prices of plastic (it used to be the cheap stuff, now it’s more expensive than wood and metal in many cases) that becomes cost effective. And of course what’s recycled doesn’t have to be imported over long distances and it saves the cost of getting rid of the material, which itself is generally bad for the environment, since it either ends up in it or is burned and causes energy expenditure and some pollution.

  8. I’ve worked in the recycling industry for over 15 years,Regarding the comment on the video on why we only recycle 10% of the plastic, recycling the plastic is fairly easy the hard part is grading and separating it. the machine he has made looks like it can only handle hard types of plastic. what about the billions of plastic bags and shrink wrap that are wrapped around everything in supermarkets etc can it handle that ?

  9. Preston Petty made millions in the 80’s making motorcycle fenders with a lifetime guarantee. Break one or otherwise become unhappy with it and send back for a new fender. Preston then recycled the old fenders into those gray bins for the USPS and made millions more. When those broke, the USPS returned them for recycling, and Preston made even more. Enough he had a really really nice Mitsubishi MU-2 turbo prop as his personal airplane.

    The color of plastic is a very important part of product design. Many times the color is highly identified with the company so color control is very important. That’s impossible with recycled plastic (unless your product is a gray mail bin). So any product made from recycled materials will probably itself be something meant to be disposed of and reused.

  10. Working in injection moulding for twenty years, I can tell you that using over 10% regrind material can be a real pain. For reliability on an industrial scale you need uniform flow and melt characteristics. Only ever seen 100% recycled material used for coat hangers and cheap builders buckets.

  11. I buy and process scrap plastics for a living.
    Plastics can almost always be recicled (there are just a few exeptions like expanded polyestirene), PP for example is recicled a bazillion number of times it goes to the landfill.
    Broom handles and bases are made of recicled PP to be more specific most are made of Solo cups.
    Regarding the lost of phisical and chemical properties of plastics with each melt, there are always way around it, for example for PE and PP you can mix them in the extruder with scrap and grinded Surlyn in 90/10 ratio to recover most of the original flexibility and strenght of said polymer.

    Ps. Expandended Polyestyrene can be recicled too, the only problem its that its too much of a hassle and its economically not worth it.

    1. Wouldn’t the low weight of polystyrene have a compensatory effect if you did it right? I mean don’t use 100 ton trucks to haul it but use some specialized vehicle, then make it as I said earlier into insulation of flotation devices or impact absorbers for instance, something that doesn’t require a huge deal of processing.

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