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Hey @s2019, oh.. a large void in explanation too! haha
I’ve used barrel nuts that are commonly used in furniture. One 10mm hole allows the nut to slide into the piece which can then accept 6mm thread. I’ve used two in that case because the cavity was so large.
Yes, left is as extruded.
As for the process, I set the blade depth on the table saw to 10mm and made multiple cuts. The chisel was for fine finishing. Our in-house hand router has a set speed that just seems too high and melts the plastic, leaving a nasty finish.
Quick update in the time that has long since past..
With the idea of creating an outdoor bench, I’ve moved into the first prototype made out of plastic to test the strength of the beams and the joinery method. This prototype is only a single seater made from the bulk plastic and scrapwood. It feels very sturdy and there is hardly any flex in the thick beams. Each leg assembly weighs just over 5kgs and I used HDPE for one assembly and PP for the other, both result in same weight but behave very different on the inside.
You can see in image 1 how the PP has cooled and left a large cavity through most of the beam, where the PE legs are far more consistant and dense. It’s also interesting to note how much more the HDPE has shrunk than the PP. The cavities in the PP meant that two rods were needed as opposed to one.
Image 2 shows the process of cutting the slot, drilling it and assembling it to the other beam. Bolts will then be used to pull the one part into the other.. this process allows for great versatility should there be any unexpected surprises inside your beam. It is also very strong if your groove tolerance is tight. Drilling the holes was also fairly straight forward taking care to mark holes properly and set the angles accordingly.
Image 3 shows the assembled peice from various angles. The surface texture differs slightly between the PP and HDPE beams, but the actual extrusion follows surprisingly similar pattern. The idea is to keep this piece relatively simple, making use of mechanical fasteners and easily available machines and tools..
Hey @ramm thanks for the contribution.. nice take on using the flexibility of the plastic, instead of cutting so much a big sheet could even be heated and bent into that form. We’re currently doing quite a bit of development with bending, perhaps we can prove your concept and inspire another workspace somewhere out there to take your design into reality 🙂
Hey @pex12, a PP academy sounds great.. master class 😎. We’ve made some adaptations and improvements (testing coming soon) to the screw for the v4 extruder.. I haven’t been too involved with the engineering design aspect so I’d ask @jovinc and @peter-bas about the exact specs for the screw
Hey guys, here’s a little update on the proj:
We’ve been exploring the directions and concepts and have concluded that it would make sense to tackle sheets and beams in separate pieces. We think this would be beneficial because exploring both sheets and beams in one piece could end up looking and feeling unpleasant.So, below are a few photo’s of the developments and explorations that we’ve made in the direction of using angled beams in a piece of furniture. In the last few days a bunch of new designers have arrived at the workspace.. (@sarahg , @niky, @leonheld, @lucytheoffcutqueen) and they will be helping push these and other concepts to their completion!
The first image is the point at which we decided to push towards something outdoor related. There has been a long debate between creating a static indoor object (like a coffee table) and a more interactive piece (like a chair). We realize that what ever we create with a fair use of beams will be heavy.. making it less pleasant to be carried around. The decision to move towards the outdoor chair was taken because it can provide a better looking alternative to current recycled outdoor furniture, it has the potential to remain in one area and it highlights some of the properties of plastic. A brief exploration of the joinery can be seen in the second image and in the third is a mockup to get an idea of the feel.
The only further developments with the board have been in the mould (it’s now completely made from Aluminium and able to be pre-heated) and we’ve tested with PS.
@jasonknight has been working on the mould. We’ve been doing much of the making in house 🙂
Here are some pics
Hey guys, happy to see this thread! Thanks for linking me @frederikc.
Some good momentum going and hopefully kept up with the PPZA Instagram and fb pages.. I’m thinking that’s your doing @georgegee?
I agree there’s huge potential with these machines in the South African context, it may just require some ‘buy in’ so to speak in order to reach the audiences that it could truly benefit. Some help in obtaining this would be to emphasize (and act with) the decentralized, ground up and human centered ethos of the project.
In JHB: there are some PP machines in a workspace called ‘The Coloured Cube‘ and a machine builder out in Germiston who has helped build some PP machines.
In CPT: I only know of a few workspaces who have used and passe d on the machines, and now only Lionel who is currently active in in building them.
But I think we need more than machine builders to get this off the ground and into the bigger picture.. this discussion and some of the workspaces currently engaged are important
There were some experiments lying around, so put together some quick mockups to get a sense of visual properties. Just playing with arrangements and ideas
Thanks for bringing that up @donald. For the purpose of this project and these products, the designs will also be under the Creative Commons or MIT liscenses. We will make it a point to note that when they’re ready.
It’s good to have this discussion, open design is not a new concept but I think it’s still in its early stages when it comes to the sharing of hardware and products. Software development has made great use of the open design ethos, but that seems to change when it gets to physical products and machines. The sense of ownership and the amount of investment when it comes to hardware seems to make it more difficult for people to share it (Big props to those who do!).
Precious Plastic as a concept still baffels a lot of people. I’m curious to hear peoples thoughts on how one would realistically go about honoring designs that have been ‘copied’. Whether that means actual royalties, or noting from where and who the design was taken.
Here are some new and old exploratory sketches. There are currently more of chair concepts, but we will diversify that soon. My initial thinking was that chairs are a bit more consumer friendly, but reflecting on that now, it may not be the case. You will probably notice I have an itch to use these new angle beams. I explored a bit of the potential for one or two simple moulds to produce various components / arrangements of products (chairs in the cases below.
Seeing as we are still exploring which furniture type to focus on (chair, table, lamp, coffee table, etc), it would be great to hear from you guys what you gravitate towards or what you think would sell best 🙂
Below are some existing pieces of furniture that highlight attributes we are looking to achieve and also to avoid.
With these values in mind we have put together this brief:
Design furniture or pieces of furniture with recycled plastic mainly using Sheets and/or Beams (The use of injected parts is not preferred but we are up to proposals). The materials that can be used are PP, HDPE and PS. The main goal is to help workspaces around the world to make profit with these products.
The challenge is to make a product/products that meet the industry/market high quality standards (aesthetic and stability through repetition) without compromising the price of the end product. The material is already expensive enough so the process has to offer appropriate speed and production costs to compensate. Aesthetic and function are very important aspects.. If it doesn’t function and look good it won’t sell.
In order to guarantee the replicability of the product around the world the product should be easy to manufacture and use accessible tools and techniques: Table saw, jigsaw, bandsaw, chisel, drill, drill press, polishing… Therefore the use of tools like: CNC milling, bending machines, planners, etc. has to be very justified or preferably avoided since they are very specific and expensive tools.
List of requirements:
1. Shift Consumers perception about plastic (from problem to value)
2. Engage with furniture makers
-Using similar equipment / techniques
-Show capabilities / versatility of the material
3. Jump from DIY to Production
-Consistency through repetition – Stable quality across same pieces. ie: Process divided by stages, Specialized Jigs etc..
4. Take advantage of the material properties
-Bending-Translucent-Good with Tolerance
-Water resistant-No polishing? (Polishing makes micro plastic and not advised for PP/HDPE)
5. Enable Workspaces to make profit
-Not everybody will have all machines
-Minimize process and steps: (making parts, assembly)
-Minimize the time of making it / Economy of time
-Minimize the amount of plastic used
6. Take into account circularity of the product
-Think about the whole life cycle
-Plastic is forever
Oooh, great link @s2019. Interesting to think of larger rigs like that for plastic.. depending on size it might be necessary to have a heatgun preheating the plastic in order for the next lay to stick. I found even on relatively small tubes, if the plastic has cooled then the next lay over doesn’t bond so well.
Thanks for sharing!
Some longer and thinner tubes. Airtight and lightweight – make for some good wind instruments!
@s2019, for now I’ve been using PS as it’s what we’re currently using for machine testing. Depending on your release agent/mould shape I think you could make large tubes. As long as the plastic you’re laying over is a bit warm/tacky the plastic will fuse nicely. The machine wasn’t running hard. I think maximum pressure reached at nozzle was about 5bar. Also running relatively slowly (80~120 rpm).. I like that dolly too haha
@pporg, we’ve also been talking of automating the process.. could get even better results.
@greendaddy cheers brother! thanks for the inspiration
Test: Flat nozzle v3
Objective: Make a tube!
Process: After no fully successful results from tests with flat nozzles, I decided to reach out to @greendaddy from Zelenew. They’ve got their flat nozzle technique working wonders! (Check it out). I basically copied their nozzle exactly and it worked first try. A piece of 1″ tube thread, cut and then squeezed in a vice. Two pieces of 5mm sqr bar were then welded to the nozzle end, with aprx 1mm gap between the two.
I built a quick jig to support a tube to work as a mould to extrude around. I was able to make a tube by rotating a metal cylinder and wrapping the hot plastic in a spiral. Thus, a tube was achieved!
-Flat nozzle and profile extrusion success!
-The flow of plastic was uniform and thickness consistent.
-If done with care, the tube can even be airtight.
-Plastic shrinks around the mould and can be very tight. Wrapping teflon paper around the metal tube as a barrier between mould and plastic greatly helped with the demoulding process
Hey @pporg! Good questions and suggestions.. So far I’ve been able to fill that mould in 10 mins. It might be possible to make that faster but again you’re looking at a balance between melt time in barrel and screw speed. Once off the machine takes about another 20mins for cooling but this wouldn’t be a problem if, as you say, you have multiple moulds.
It might be interesting to see if we can add a ‘reserve’ for plastic to be stored and melt fully before the next injection. So far I’ve been able to leave plastic in the machine for over an hour with no signs of burning (provided your heaters are staying where they need to stay)
Noting how the plastic flows much faster in the middle than on the edge I wanted to try fix that by drilling two holes on the edge. The idea was to offer less resistance to the edges allowing the plastic to flow more uniformly.
The results were relatively successful but I think there is still room for improvement.
If you look closely at the plastic in image 2 you can see a small build-up at the edge of the nozzle. This may be due to the rough edges caused by grinding the slot.
Test: Flat nozzle v2
Objective: Make a tube!
Process: In an attempt to improve and simplify the flat nozzle, a thin cut was made into a piece of 4mm steel sheet. The nozzle was left to sit on the machine in order get warm. However, results were not so great. The flow of plastic was in faster in the centre than at the edges and produced a ball of plastic. Sheet was flipped around and a similar result occured.
-This design for a nozzle – also not so good.
-Flat profile was not achieved and plastic deformed into a ball.
-The flow of plastic was not uniform, faster in the centre than the outside.
Making a tube without the use of a ‘tube’ die would require a different take on the method used. The idea was to use a large, flat die/nozzle to wrap around an existing tube. Here are some results.
Test: Flat nozzle
Objective: Make a tube!
Process:For this test a thin metal rectangular tube has been clamped, hammered and shaped into a desired shape. Tabs were then welded onto to the shape so that it can be connected to an existing attachment. Time was taken to ensure a flush fit between the ‘nozzle’ and the flat plate. Results of initial tests were not so successful (image 1) as the plastic began to cool before leaving the nozzle. Another attempt was made after pre-heating the nozzle which provided a slightly better result. A big downside to this design is the amount of waste left in the nozzle and the extra energy needed to heat it up.
-This design for a nozzle is not so good. Plastic did leak and left overs are ‘waste’
-A flat shape can be obtained but the process is slow.
-The flow of plastic is not very uniform.
-Pre-heating the nozzle did help.
Ok, so the idea of making a ‘simple’ tube from recycled plastic is fairly straight forward and seems achievable, right? We’ve got a strong extrusion machine and a workshop full of other machines.. but after really getting into it, making a plastic tube (using current methods) actually requires a LOT of knowledge and infrastructure to achieve. In the images below you’ll see:
1 – a basic render of the concept behind making a tube (hey, we can do that!)
2 – a cross section of a die (hmm, lots going on)
3 – an exploded view of the different parts needed (that looks big)
To get an idea of the scale and infrastructure needed for the process of making even a small tube you can also watch this video (pretty amazing!). Note that this example is an industrial and highly ‘productive’ system but the steps in the process of making tubes would need to be similar. Such as the die, the cooling method and pulling machine to maintain dimensions/flow.
With all this considered I began to lower my expectations of making tubes in these methods due to our current machine setup and the knowledge needed to get a good result.
My thinking is that there’s already a world out there, a massive industry making perfect tubes with huge tools and big budgets.. Now I’m not saying its impossible or this technique shouldn’t be tried but when looking at our machines and this project as a whole, I feel that time could be better spent in other areas of the development.. for now
Here’s an inside look at how a beam is born 🙂
Test: Larger product moulds for Extrustion.
Objective: Use simple materials and techniques to create larger product/moulds using the extrusion machine.
Process: A (found) wooden shape with a draft angle was used as a reference to build around. Wood and 3mm sheet was used to create both male and female halves (image 1). The mould is almost completely dis-assemblable, top and bottom can be removed and interchanged for different materials.. (more experiments to follow). For now only the metal mould has been tested with Silicon oil as release agent. The mould is not airtight and the current machine has a pressure sensor so we’re able to monitor the pressure during the run. We stop the test when plastic can be seen at the furthest edges or pressure reaches 30bar.
-The extruder, used as an ‘injector’ is able to fill larger more complex shapes.
-Cold moulds (15-40 C) create an organic surface finish but parts are not completely fused. Without some pressure sensor it may be hard to know when to stop the machine.
-Hot mould (180 C) allows plastic to fill entire cavity and surface is smooth. It is also easier to monitor the state of the injection as the plastic begins to leak out the small gaps.
-The 3mm steel began to bend at 30bar. This could be fixed with reinforcment of large flat surfaces or a thicker material.
Hey @copypastestd, thanks for you questions.
The speed mentioned is the speed of the screw itself, I’ll have to find out what the exact reduction is.
The only heaters are those on the extruder itself. To get a hot mould, I’ve been extruding a beam, demoulding asap and then using the mould again while it’s still hot.
What material have you been using and what temperatures? Your beams look smooth and consistent.
Perhaps the issue of not being able to extrude longer than 50cm is that plastic is not warm enough to maintain the flow or your machine is unable to maintain the pressure
Hey @copypastestd, for releasing the PS beams we gave the mould at least 30mins to cool. The beams we did make were also not too long.
Circular / square shapes seem to cool more uniformly and are easier to release than the rectangular shapes. So far we’ve had no need for release agent in beam moulds
Test: Flat Wooden Guitar mould
Objective: Find simple, alternate ways of producing large objects with extrusion
Process: While @cymek was still around, he had the idea of using the extruder to make a guitar body. We used sheets of 18mm plywood and CNC cut one profile into 3 of the 5 sheets. This allowed us to change the thickness relatively easily. The aim of this was to keep it simple – so we simply screwed on a mould fitting and ran the machine as fast as we could. The mould was fastened together with screws and we used a lot of clamps to reinforce the flat areas during extrusion. I wouldn’t say the results are successful, but we did learn something.
-Clamps aren’t enough to hold back the pressure. Some clamps bent.
-The plastic did release quite easily from the wood.
-We were not able to fill the mould completely and it was hard to monitor how much more there was to fill. However, the plastic was able to reach the very tight corners.
We’ve only brushed the surface and there is still quite a bit more we could try with this concept. If you have any suggestions, shoot!
hehe @malyboa, if we don’t try we’ll never know! I quite like this technique. I think it really opens up a lot of possibilities.. Angle joints take a bit of time making strong and pretty.. this way of doing things could create far stronger parts and with less time. In the coming months we might push this technique into different applications and designs. For now I’m just exploring 🙂
Hello everyone, sadly @cymek has had to return to the US of A. The main man working on development of the extrusion machine is now @peter-bas, who has been making some improvements to monitor the machine.
If you’re curious to see or have any ideas / suggestions with regards to the techniques – check out these topics: