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I need to make time to check in here more often. It’s exciting to see your efforts towards continuous output extrusion, this will be an important improvement.
I started building a water-cooled beam mold as well but haven’t had the time to complete and test it. Rather than drip cooling I made a jacket through which water can be circulated. I wasn’t sure whether I was on the right track but your results are encouraging.
I’d be happy to share any information with you on the machines I have been building, if that would be helpful. Feel free to send me a message.
Keep up the good work!
Great work Mark! Thanks for the great documentation.
Have you tried using aluminum sheet for the mold surface? This is what I have been using to make smaller sheets. Sometimes I use a light film of WD-40 but have also had success with no release agent at all. HDPE and PET came right out of the form without any sticking. PP can take a little bit of convincing but I think this is because the material I have been using is mixed and has some contamination.
You can see some examples on my IG page: https://www.instagram.com/preciousplasticusa/
Thank you for sharing your efforts!
There is a bit or a wait list right now, but anyone interested in having machines built should get in touch, there’s a busy summer ahead.
@fabirihotmail-com I used DOM seamless tube with 1″ ID and a 1″ Auger bit. I’ve used both .188 and .120 wall tube, .188 needs to be turned down a bit for NPT threads to be cut, .120 is a bit small and threads are flat but it works. Since you are in Europe, you should be able to source the metric sizes specified in the original design.
DOM (Drawn Over Mandrel) tube is often used for racing roll cages, so if you are having a hard time finding it maybe you should check a local shop that builds race cars or supplies race car builders.
That photo is not very helpful in showing your issue.
The corners in the files are all square, so if your pieces are not, there is a problem in the cutting. If parts are not lining up you may have them oriented wrong or need to do some d-burring.
Here are photos of the blade preparation, both tips and shearing edges should be sharpened to improve efficiency and durability. (Modified parts on bottom)
The tips of the blades should be ground to chisel points which are much stronger and cut better than the thin tips on the laser cut parts. I always grind the tips off and re-grind with an angled chisel tip. It is extra work but worth the effort.
Sorry, I didn’t see this last comment earlier.
Making consistent filament can be tricky with the basic extrusion machine and perhaps more so with human power if you extrusion speed is not well regulated. However it sound like it would be a cool experiment. I could certainly build you the basic extrusion setup but it would probably get a bit pricey for me to do a one-off pedal powered drive system.
Generally speaking, the concept of running both machines with one drive unit seems very practical and more economical than using two separate machines. The issue is that both machines have different power and speed requirements, so if you are not careful you can do some damage.
I built the machine in the photos above and am currently testing and developing it. The motor is spec’d out for the shredder and intended to put out significant torque needed to chop up plastic, however the extruder doesn’t need all that power and the Precious Plastic design did not have it in mind. Therefore if there is any binding in the extrusion barrel, all torque from the shredder motor can break the auger and bend the frame.
So basically, the concept is good, but if you don’t use the tool properly you can do some damage. Currently working to find the right balance of durability and performance.
Nice work! Great idea with the aluminum channel frame. That motor and worm-drive are nice an quiet.
Parts set includes all parts to build a shredder mechanism. To build an entire machine you will need to purchase a motor, gearbox, wiring, then build a frame and hopper.
(blade spacers are missing from the photo but are included)
I’m selling full sets of parts for DIY builds and complete units. Cost includes domestic shipping and a donation to Precious Plastic. With all of the parts and shipping added up you’ll find that the pricing is competitive with most other options and saves a lot of time researching and sourcing.
I do have listing on the Bazar but have been receiving inquires from both sites as well as the Facebook group.
Just like Marcus suggested, you need some shims.
Like These the shredders I built had the same problem each needed .012″ on each side and tightened the assembly right up. if you loosen the collars on the bearings (where the shaft passes through) you can shift the shaft side to side and determine how much play needs to be made up for. (best done with a dial indicator but you can get close with feeler gauges).
Also make sure that there are no burrs on the knife spacer washers and inside edges of the fixed blades, these clearances are pretty tight and interference is common if the parts aren’t smoothed out.
As Peter mentioned, DOM (Drawn Over Mandrel)tubing is seamless and available in a number of sizes and wall thicknesses, this is what I am using. It is commonly used in building race car roll cages and tube frames but not all metal suppliers deal with it. It may not be the cheapest option but Online Metals sells it is small quantities and you may be able to buy small remnants from a local race shop.
I am starting to build machines here in the US. Finishing some shredders right now then starting on extruders and injectors. Anyone interested pleas get in touch and we can discuss options.
Hi all. I am working on building a small batch of shredding and injection molding machines here in Portland OR. Materials have been ordered and the goal is to have the machines completed by the end of the month.
I still have one shredder and two injection machines in the production run that have not been committed to anyone. If you are interested please get in touch and I can provide pricing options and shipping estimates.