DIY Plastic Shredder 2.0 

Why don't you copy my design, a 24V 350W motor can handle the whole bottle

Really good work. Surprised by your preference for stainless. You'll find the spec for hardox in the original spec is significantly better than stainless. If you've got parts that are working, corrosion isn't going to be a major concern, plus you can weld hardox like mild steel, it's crazy tough, no tricky distortion, no blunt cutting faces.

"I actually desired a two to three kilowatt three-phase induction motor-driven worm-drive gearbox coupled plastic-eating monster people call a shredder." Subbed.

ok i understand that the geared systems are smaller and more robust over time but a cheaper and easy speed and torque setup would be to use belts and pulleys , a couple of double pulleys on pillow block shafts and you can get your gear reduction and keep a lot of torque

Good work. I now see that my dream of an economical way to shred all the plastic packaging I get is unrealistic. The horsepower required just to shred a plastic bottle is surprising. I looked at commercial shredders, and they are way out of my budget. After watching this, it's fairly clear why. I assume they use heat treated steel to allow the cutters to hold an edge. I got nervous watching you poking the beast with that chunk of wood. If the hopper had vertical sides (i.e. a rectangular tube, not a frustrum), you could use a slightly smaller rectangular piston to push the cartons down safely.

Great video. I suggest trying a blade layout that pushes the plastic from the sides towards the center. All of the people I've seen try these shredders align the blades in a way that pushes the plastic to one side and end up with asymmetric forces that deform the metal just like you saw. Also, you probably need a second stage to shred into pellets, so using the paper shredder there might work.

You just need all torque no speed with the first...oh youre getting there

the luandrymats have no.2 recyclable plastic for 3d printing

You trying to make gas?

Perhaps having two meshing shredders feeding the material between them? What about making blades with interchangeable carbide cutters, such as those used on lathes?

Such a fun project, however, as a swede i get money back from recycling the plastic bottles at the grocery store... So i don't know what i would use one for =)

update. I tried that configuration. yes it works, but it was easier to have some 10mm steel laser cut vs doubling up the thinner parts.

Creative video, thanks :)

Subbed right away! Keep the videos comming and have a nice day :)

I love the classic pronged cross cut paper shredder blade design this is the “EUGH holy crap” more gnarly looking version of that all it needs is the double edge cut into the blades

i recognize that design

You did a great job of trial and error and keeping at it! I see what your problem is with your blade teeth layout. The assembly as a whole layout needs to be one in which the turning direction constantly pulls any gripped plastic into it as the blade teeth rotate though the cutting wall so plastic is constantly pulled in and cut apart. The best layout for that is a staggered but tight spiral If your blades were thinner. Make use of those thinner teeth but spread them out in rotation to where a stagger will always have a tooth rotating through the cutting wall or is just about to. That keeps the force of pull in for pinched plastic. That would also cut down the shred grain making the shredded plastic smaller. With your current layout, there is not a constant lineup of your teeth to pull in. There is a lined up cutting row then space, lined up cutting row and space, that is why you are getting the feed rejection and bottles jumping in the space between the teeth turning through the cutting wall. Its a grab, let go, grab, let go type of layout. Even thinner blades would give you more pulling force versus what you have there with them paired together and you would need quite a bit more of them so they don't deform. The close stacking effect helps to ward off that. 2 tight complete spirals that were split in the middle and then offset so they are a bit out of phase with each other is one idea or go with the classic V. Blade teeth in the middle hit the cutting wall first then taper out and back on both sides to the end of the shaft. One side of your V could be a more acute teeth taper angle back in rotation and the other side more obtuse for grabbing larger plastic pieces. Different pulling forces, are achieved by the tighter spirals, they never have that air gap and never let go. All that matters is the rotation of the teeth through the wall being constant enough to keep the plastic pulling into the entire blade assembly. I keep thinking of Whoopi Goldberg in Jumping Jack Flash where her dress is caught in the office shredder which almost leaves her naked. The pulling force is strong like that with some shredders having more thin cutting teeth that never let the objects go. They play the numbers game because the higher the number of teeth rotating through the cutting wall at almost the same time means quicker shredding. Its like the design of your paper shredder. The teeth were not the biggest problem it was the motor and electronics. That tooth layout grips things very well. Great video, thanks for posting it!

"I'm not a mechanical engineer" That's a good thing, because a mechanical engineer would have spent way too much time building something that is needlessly complicated and can't be easily repaired.

I’m looking for something similar but to shred PCB boards

Looks like you need alot of torque for that. What about a chipper with flailing arms or lawn mower blade where it hits it like a bat & both brut strike force & repeated blade cuts chop it down

can i ask, if you were to change the material to wood or also from plastic, would it work? i am just curious

Can you please try this shredder design on cardboard

great video but the cost......not today

Try adding a set of larger rollers above the small so it feeds better. Hope it helps.

Thanks for all the info.

Fantastic shredder project, great commentary, well documented, and entertaining too. Well done 👍

how much does your shreder

Have you done any pvc shredding

Have you ever considered preheating the plastic prior to trying to shred it ? Not melting temperature but a temperature that softened the plastic

Was there a reason why you changed the design of the blades. The first design seemed to shred the plastic to a more smaller and thinner size.

Excellent

that green bottle was fighting for its life

GREAT JOB THANK YOU.

How can we make these teeth more readily than lasering steel? Can we use 4" carbide tooth sawblades? I might think about this.

Very good. Price please.