archived-shredder-dev

Hi ! This channel is dedicated to the development of the new shredder PRO. Anyone with the badge @Contributor, can read and participate ! For the records, a few months back, WEIMA contacted us to help us design a new shredder PRO. They are a very renowned shredding company, so we got very excited to work with them and we immediately went to Germany to meet them and draft this project. A few weeks later, they came back with this general idea : https://drive.google.com/file/d/1KjsbZRWkdKs3x0fE2-iLd9HKTYp13xcA/view They think we need to make a radical design change from the shredder PRO and go back to a single axis. Their experience is showing that two axes is not efficient, and if we want to go on the multiple axis world, the shredder needs to have 4 of them, which is incompatible with affordability. This model would allow different rotor designs, to compensate for different machinery ressource and allow different prices depending on the context. Finally the sieves will also act as pushers that are manually operated. These pushers can also be motorized in contexts when the workforce needs to be optimized but initial cost is less problematic. And now, what you are all waiting for, the first prototype in action : https://youtu.be/bwAbHozODOk ! Now we will prepare a second trip to Weima’s factory to test some different plastics and discuss potential optimisation. Feel free to drop your ideas hereunder !

Precious_Plastic_x_WEIMA_shredder_pro.pdf

WEIMA shredding & compressing

Precious Plastic X WEIMA | Shredder Pro prototype V1

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Looks awesome! Only concern is rolling the pusher plates/parts - I think a lot of laser shops have CNC brakes for bending but not necessarily for rolling. Could a design work that has a faceted pressing lever to push plastic in or does it have to be a smooth arc/circle?

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It appears that the shreds are still a little on the large side.

Yes this is definitely a good point. The bending is also my main worry with this design, that need to be simplified.

5:53 PM

I agree with you Abe, but I think they use one of their sieve for making this first prototype, which are bigger as their specialty is wood shredding. But I will confirm and see how this can be reduced.

Nice shred, but don’t mix plastic

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We build some of the Precious Plastic machines years ago but the shredder was always an issue. We ended up buying 2 single axis shredders at auction and were really happy with them. We have one in use and have a big yet manageable industrial shredder for sale. You guys probably already looked at how other shredders are build and probably already have a nearly finished design but I dont mind taking some pictures from ours in case it helps. Aside from the blades probably having to be made professionally most of the case can easily be welded and a motor reused. Similar to how the screw of the extruder is a part you purchase. I really think,you guys are going in the right direction by going for a single axis shredder and I hope

Very cool design. I like that the model in the video doesn't have blades. The biggest issue I currently have is the blades jam if I'm not careful what I'm shredding. Also they can shred film! I'm guessing the cost of the cutting barrel(s) is more that the current shredder blades?

I am glad that Precious Plastic is finally going towards a single axe true shredder system. @Abe, in theory the shredder is only the first stage, you then have to granulate your plastic to small size. A big step for the project

4:35 PM

If you allow me, dump the gearbox madness and use belt drive. The price will significantly lower, you will waste less energy and it is much easier to source.

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Hello ! I will meet online with Weima tomorrow to start discussing about the shredder, please drop below your eventual question and comment !

6:49 PM

Then I will go visit their factory to run some test the 8th of July, is there anyone close by that would like to join, ideally with some filming skills so we can shoot a little video

They are north of Stuttgart in Germany by the way. @Thomas Peterberns | Johannplasto ?

Yann

Then I will go visit their factory to run some test the 8th of July, is there anyone close by that would like to join, ideally with some filming skills so we can shoot a little video

They are north of Stuttgart in Germany by the way. @Thomas Peterberns | Johannplasto ?

Sounds good! But it’s still 9hours by train from Dresden. I have to check if it’s possible. (edited)

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8:54 PM

This is a Pro box I've designed inspired by the laser cut blade options shown in the document that was shared. Running now at 50 rpm to test. Very powerful, ~2500nm, tearing through large format failed 3d prints and waste cutoffs from lasercutter today. (edited)

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2:41 AM

what you think? based on the v2 shredder. only file changes are the side plates, and the blade tooth profile. delete the fixed blade.

Hi Butte ! Might worth a try for a small double axe shredder. But from experience, I would not remove the fixed blades. I personally tried it a couple of time with the current shredder PRO and breaking the bearing all the time ! The shredded plastic will get stuck in between the teeth if not cleaned with the fixed blades, this will create a radial force pushing the axis to the outside. Thankfully the bearing are the first to break, creating a not too bad mess, but still.

11:38 AM

So I would highly suggest to add fixed blade, cleaning on both side, if you want to go on the double axe.

11:38 AM

CitSciWorkshop

This is a Pro box I've designed inspired by the laser cut blade options shown in the document that was shared. Running now at 50 rpm to test. Very powerful, ~2500nm, tearing through large format failed 3d prints and waste cutoffs from lasercutter today. (edited)

That look amazing, do you have some video of it running ?

Yann

That look amazing, do you have some video of it running ?

Yeah, getting clips of testing for the next few days.

Second version of the new shredder PRO is coming ! Globally the concept works, and is nice to use, now it is time to optimise the process and the cost of the machine

-> It is confirmed that the manual levers are nice to use : they require very little pressure and there is no “push-back” even pressing harder material like PS. So for cost saving : just a straight sticks and no bearing. -> The screens / sieves will be simplified : reduction of the thickness to 4mm + bending line. The screens will be able to be manufacture without bending or rolling machine, only laser-cut and welding. -> Also screen holes will be reduces to 12mm (there were 20mm in the video), this should give smaller flakes with a still acceptable throughput. Smaller holes will have too much impact on the productivity, and as said @PlasticAtBay_Julien_NScotland having a shredder that also granulate is utopic, so we are staying on the shredder side, there is already a lot of good and cheap granulator out there.

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5:18 PM

-> Remove the lid on top of the shredder and replace it by a 900mm height hopper. There was not enough feeding with just the casing, this high hopper should offer enough space for 10min continuous shredding, be safe, and can be reloaded easily and continuously. Simplification of housing design assembly: sticking together for easy welding -> Housing will be simplified with “puzzle” joinery for welding and some bolting. -> The rotor will be changed for a laser-cut one, to be able to be reproduced everywhere and have a lower cost. The double direction shredding is kept, therefore the particular blade design. To build this shredder, only laser-cut, welding and drilling will be necessary (no complex milling, no bending or rolling etc…). With the exception of the axis that will require lathe and mill job (as the current Precious Plastic shredders).

5:19 PM

https://drive.google.com/drive/u/0/folders/1Z1FD5HRVRvjejAut21_gmM7KL01XjA8e

@CitSciWorkshop looks good. can you show us some shredding video? what about the side blades?

ShrednMelt_Xu

@CitSciWorkshop looks good. can you show us some shredding video? what about the side blades?

We're using a comb and will likely be adding a hardened plate with a reverse edge for additional shearing. Like I said, we're getting clips of various tests in the next few days.

If you allow me, I suggest you plan a conveying system via a pump or a chip extractor.

12:05 PM

It is just the matter of welding the right size of pipe. car exhaust pipe is pretty cheap. also the tray needs to have a little deep

Has anyone attempted a shredder construction using 3D prints instead of metal? I’m fully aware it won’t have the functionality, throughput, or power that an equivalent v4 shredder box would have, but I am trying to make something that would be a little more accessible for classrooms to produce. I’m currently in the middle of building the v4 via 3D printing, using carbon fiber reinforced PLA and 200 micron tolerances on the blades - potentially considering reinforcement with steel epoxy on the cutting areas. Some parts such as the threaded rod, pillow block bearings, and machine screws I’m picking up locally as they are easy and cost-effective to purchase. While I am not expecting this to shred gas cans or milk jugs, I am hoping it can handle spaghettified 3D printing filament (Plain PLA, mostly) and failed prints under a certain width. Basically to allow technology classrooms to build their own shredder and repurpose their own PLA waste. We’ll find out!

7:24 PM

Puddle of parts. Clear parts were laser cut from 3mm acrylic, all else was printed from carbon fiber reinforced PLA. We’re gonna test the parts raw, then try heat-treated, and then finally epoxy reinforcing select pieces such as the rotating blades and fixed knives.

7:28 PM

Our shaft assembly

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Another idea for blade reinforcement was electroplating, and we’ll be looking into that as well. We will be taking photos, videos, and fully documenting this process on our website once that is up. We’ll take videos of all the tests, so that we can help others learn whether this is an interesting offshoot to try, or simply a really bad idea from people with too much technology and time on their hands. Either way, we hope to help the entire community learn something out of this.

It fits together, spins nicely without catching, and can shred spaghettified filaments (PLA and carbon fiber PLA) by hand turning. Next up is building or 3D printing a handle for extra torque, as well as trying to get our motor attached.

5:01 PM

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5:05 PM

We’re going to add the rest of the frame laser cut from acrylic, and also try to gear down and attach a motor. The motor we currently have is from a disassembled black and decker circular saw that might be 20-30 years old. Motor specs as is are 5300 rpm, 120v 9a, originally used with 7-1/4” blades. Any ideas of how to gear down such a spin-y motor into something more apt for a shredder? I was thinking a 1:100 planetary gear system but am struggling with how to get all the parts fitting together…

5:07 PM

It has a button wired in, so that’s nice.

5:08 PM

I will note this particular build is NOT for continuous use but for “burst” shredding in a classroom setting as needed

5:10 PM

If there is a super easy motor I can yoink from a common (USA) product, PLEASE let me know because I am trying to find the easiest / cheapest sources for these builds that does not require the purchase of a brand-new motor.

Hello guys! New here, im trying to get a shredder in my workshop, but i have some issues: 1. My country barely allows to import machines from other countries 2. Plasma cutting/CNC isnt a cheap option. Any recommendation on how to make the shredder box?

I’m testing a 3D printed option utilizing carbon fiber PLA blend (see above), but stalling at motor integration. My local team is very small - an IT-and-electronics educated hobbyist with a minimal engineering and manufacturing background, and a non-technical administrative support who is learning alongside. We’re hoping to recruit someone with a better mechanical understanding soon who may be able to help us design a decent gearing system that is functional as a 3D printed part. The white end piece was standard PLA as I realized after printing two of the side pieces that I needed to reverse the part on the Y axis to ensure proper compatibility, and didn’t want to switch out filaments if I didn’t have too - we’ll see how this impacts the build over time. Parts were printed on a snap maker 2.0 A350 model, and took several weeks of printing and many calibration headaches to ensure parts were up to scuff, but overall the costs of the materials of the parts were under $150 usd not including my hobbyist labor converting the parts to .stl or ensuring tolerances /sizing /proper printing parameters, est 1-2 hours per part design. We fully expect some form of catastrophic failure upon motor integration unless we can get the speed /torque juuuuust right - and if it doesn’t explode then, we’re gonna see what kind of materials it takes to break these teeth. I’ll group the .stl files I used (ripped and converted from the autocad drawings, the only one that needed a size modification was the hex rod) and upload those at some point soon in case anyone else would like to try this out alongside. Keep in mind part sizing may need to be modified to ensure proper fit as the end-result is always dependent on printer resolution.

Smarterer

I’m testing a 3D printed option utilizing carbon fiber PLA blend (see above), but stalling at motor integration. My local team is very small - an IT-and-electronics educated hobbyist with a minimal engineering and manufacturing background, and a non-technical administrative support who is learning alongside. We’re hoping to recruit someone with a better mechanical understanding soon who may be able to help us design a decent gearing system that is functional as a 3D printed part. The white end piece was standard PLA as I realized after printing two of the side pieces that I needed to reverse the part on the Y axis to ensure proper compatibility, and didn’t want to switch out filaments if I didn’t have too - we’ll see how this impacts the build over time. Parts were printed on a snap maker 2.0 A350 model, and took several weeks of printing and many calibration headaches to ensure parts were up to scuff, but overall the costs of the materials of the parts were under $150 usd not including my hobbyist labor converting the parts to .stl or ensuring tolerances /sizing /proper printing parameters, est 1-2 hours per part design. We fully expect some form of catastrophic failure upon motor integration unless we can get the speed /torque juuuuust right - and if it doesn’t explode then, we’re gonna see what kind of materials it takes to break these teeth. I’ll group the .stl files I used (ripped and converted from the autocad drawings, the only one that needed a size modification was the hex rod) and upload those at some point soon in case anyone else would like to try this out alongside. Keep in mind part sizing may need to be modified to ensure proper fit as the end-result is always dependent on printer resolution.

Thanks for your ping in the other channel. I guess my first question is in regard to the necessity of 3D printing the pieces? Is is a sort of crash test? We use 1045 steel for axles and AR500 for the blades currently. Steel hex bar is available in various sizes, and its a matter of turning down the round parts of the axle to the common diameter of a coupler . It definitely would not fail before anything that was printed.

Basically, yeah - a crash test. Wanted to see if it was possible (it works by hand on spaghettified PLA from catastrophically failed prints! - Haven’t installed sieve yet as we’re still trying to figure out next steps for the shredded pieces which will determine sizing) Our end hope is shredding EPS and HDPE bags, not anything too tough to thick really. The full intent is to create a mini Precious Plastics curriculum to allow local k-12 teachers and students recycling materials within their school’s technology and design programs. This is seeing if it is feasible to design and build something using equipment fairly available to those teachers and students, particularly high-school STEM programs integrating topics like reverse engineering, basic electrician training, and products design and manufacturing.

Smarterer

Basically, yeah - a crash test. Wanted to see if it was possible (it works by hand on spaghettified PLA from catastrophically failed prints! - Haven’t installed sieve yet as we’re still trying to figure out next steps for the shredded pieces which will determine sizing) Our end hope is shredding EPS and HDPE bags, not anything too tough to thick really. The full intent is to create a mini Precious Plastics curriculum to allow local k-12 teachers and students recycling materials within their school’s technology and design programs. This is seeing if it is feasible to design and build something using equipment fairly available to those teachers and students, particularly high-school STEM programs integrating topics like reverse engineering, basic electrician training, and products design and manufacturing.

If you want something that uses plastic as an analog, there are these type of hex bars available via McMaster, https://www.mcmaster.com/plastic-hex-rods/shape~hex-bar/material~plastic/width~3-4/

10:30 PM

Then creating a hex to keyed coupler could be something you 3D print.

10:31 PM

as far as a small motor, maybe look for geared DC motors, like a windshield wiper motor. Caveat here is I would not expect to use any of this to act as more than a moving demonstration.

Thanks! That definitely gives me a few more places to jump from. Modified a design from thingiverse and now 3D printing a test coupler to attach the existing shaft to the 7mm hex attachment on an adjustable torque 12v dc drill. I don't have high hopes for this rendition, but it will be fun to see if it spins plastic better than my poor hands can do it.

So - PLA coupler #1 “works” as a motorized demonstration tool, however the hex side that attaches to the drill tends to free-roll inside the coupler the second the shredder encounters anything more than a few pellets of EPS. We are hoping for a bit more function than that. Adding keyholes and extended coverage to the hex side (10mm depth to ~25mm depth) and printing coupler #2 also in PLA overnight, if this works better on torque tests tomorrow, we’ll bust out the carbon fiber filament tomorrow and see what it can do.

7:43 AM

Exciting note - drilling holes to add keying to the hex side of PLA coupler #1 significantly increased torque to shredder, and after it passed our EPS test, we were able to partially shred (half of) a solid polystyrene cup before the first coupler catastrophically failed, which is WAY MORE ability than what we were expecting of a 3D printed shredder.

Solid coupler worked great, and the next point of failure was the shaft. Broke on the Y/Z plane between the blade section and the side bearing after several successful runs using EPS as well as a run of smaller fragments of the PS cup. We knew this axis would break as it was only printed with ~60% infill and minimal walling to save filament as this was our second fit-test axis while adjusting part sizing to compensate for the resolution of the 3D printer. We're gonna diverge this into two separate shredder boxes now. For the next update to the existing shredder box, we're gonna reprint the shaft with carbon fiber PLA new infill settings, aiming for a completely solid part. This part will also be heat-treated prior to assembly to help improve it's overall strength and function. None of the other existing parts have been heat-treated or had any other form of post-processing after printing. For the 2nd version I'm intending to redesign and re-print the blades and spacers so that we can utilize a hollow square steel tube as the shaft/axle. This is relatively cheap and easily available in my area, and can be used as-is rather than needing to be machined / turned down from stock. The square tube should provide enough force on the blades, and a carbon-fiber PLA keyed adaptor will allow the square tube to fit into the same bearing size so no other parts should need to be adapted before printing. I found a 3D printed version of the bearing, and while I have very little hope for it's actual functionality I am going to try and print one just for fun to see.

I find sincerely useless and wasteful the idea of making a shredder for plastic from plastic. Maybe it can be useful for vegetables.

I got my shredder

hello

2:34 AM

anyone here

2:34 AM

????>

would a plastic hopper be recommended for the shredder 3.3v

Alex_recycles and creates

would a plastic hopper be recommended for the shredder 3.3v

it can work, i wouldn't say is recommended but its possible (edited)

Just watched again the "classic" version of the blade of Weima design. Seems pretty doable with the machinery I use at job. If needed feel free to ask, my employer is interested in the project, so maybe we can cooperate in the development.

Hi everyone, I'm a mechatronics engineer and wanted to have a look if I could help out with improving the design of the machines. What are currently the most important challenges that people are facing when using the shredder?

guys, im looking for the shredder files but one with no welding, anyone have a link at hand?

Niels Bosmans

Hi everyone, I'm a mechatronics engineer and wanted to have a look if I could help out with improving the design of the machines. What are currently the most important challenges that people are facing when using the shredder?

Only regarding the double shaft shredder: From what I read in the past year, to me seems that the plastic in the shredder can melt because of the friction, since the blades aren't close between eachother. I'm developing a shredder with blades made from a solid bar. The design isn't "offical", is a personal project. Since I'm a lathe machinist, and since my employer let me to use the lathe at job, I decided to try to follow my path. At the moment the development stopped in last november ( I had some personal issues) but my concept is to make a shredder that cut the plastic instead of shredding. So I made a pair of rotary blades from solid (39NiCrMo3 steel, quench hardened), with a very small distance between eachother (0.03mm) nitrided to enhance surface hardness, to ~65HRC. At the moment I have to do some metalworking (I have to add a tab to fix the longitudinal play of the fixed blades) and to test it. For the moment I can say that with only 1.5kw@15rpm it can shred thich HDPE (from plastic crates, not caps!) with no issues. The only issue comes from the axial/rotational fixing of the static blades. I put a 12.9 M6 screw on every blade, but they (only one of them during testing, to be honest) doesn't stay in position during shredding, so it seized rubbing against the rotary one. Let me to wait the temperature to go down (I can't stay in the factory more than the 8hours when the temperature is over 30°C) and I try to solvecl the issue on this design. If it is OK I'm thinking about releasing the blueprints and adding the machine to the bazaar.

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does anyone know were to get good motors

9:37 PM

for a vs 3.3 shredder ?

9:41 PM

motor

I ran into a problem

5:04 PM

So the motor requires 1.5kw and my outlets only give 110 to 120 volts

The amps is 10-15

5:27 PM

Would if I use a less 1kw motor but with a gear box that increases the rpm

5:27 PM

?

Alex_recycles and creates

So the motor requires 1.5kw and my outlets only give 110 to 120 volts

You don't have much overhead but it can run 1.5kw on 120VAC isolated and with a VFD controlling the load. I suggest a 30:1 gearbox

9:03 AM

VFDs that convert single to three phase at 120 are uncommon but ATO brand has a model. I can help you if needed.

Hello, I am a space engineer interested in sustainable economy and recycling materials. I recently bought a monoshaft shredder on the bazar and thought it would be a good idea to start gathering some info from people with more experience while I wait for it to be delivered. My plan is to use a monophase motor (1kw power) with a gearbox capable of reducing it's high rpm to something in the range of 30-60 rpm. I am unsure about what components I need for a motor controller capable of protecting the motor from overloads and possibile non-nominal situations that could come up with use. Is it a simple circuit breaker an acceptable solution? Thanks to anyone who's gonna answer!

Astrorick

Hello, I am a space engineer interested in sustainable economy and recycling materials. I recently bought a monoshaft shredder on the bazar and thought it would be a good idea to start gathering some info from people with more experience while I wait for it to be delivered. My plan is to use a monophase motor (1kw power) with a gearbox capable of reducing it's high rpm to something in the range of 30-60 rpm. I am unsure about what components I need for a motor controller capable of protecting the motor from overloads and possibile non-nominal situations that could come up with use. Is it a simple circuit breaker an acceptable solution? Thanks to anyone who's gonna answer!

A specialized motor circuit breaker would be a better solution (not the only one), something like these https://catalogue.lovatoelectric.com/gl_en/Products/Motor-protection-circuit-breakers/CAP01/pc

11:05 PM

check well for compatible values with your motor's

is their a tolerance for the N/m for the shredder ?

4:24 PM

like it can be less than 300N/m

Alex_recycles and creates

like it can be less than 300N/m

Any less than this and the machine will tend to jam more often.

I was thinking about using a crane motor for the motor for my shredder. The motor can lift 400lbs that should give more than 300N/m

https://youtu.be/NL-k8kJ8yig

Teaching Tech

Recycling waste 3D prints with a Precious Plastics shredder

Just take care not to overheat the motor, as these are not done fo continous use.

for me the motor I will buy can lift 400 lbs precious plastics recommends a motor that can lift 200 lbs

200 or 400 lbs does not say anything about torque. To calculate torque you need to know the power (hp/kw) and revolutions per minute. http://wentec.com/unipower/calculators/power_torque.asp

you can convert

3:41 PM

I put 300 n/m to ft lb and it was 221.26 ft lb

3:42 PM

so 400 lb is around 500-600 n/m

CitSciWorkshop

Any less than this and the machine will tend to jam more often.

What about 400 to 500 N/m

3:41 PM

?

Alex_recycles and creates

What about 400 to 500 N/m

Seems fine, just make sure your frame is built well to withstand the force.

My motor came in

Yann

Second version of the new shredder PRO is coming ! Globally the concept works, and is nice to use, now it is time to optimise the process and the cost of the machine

-> It is confirmed that the manual levers are nice to use : they require very little pressure and there is no “push-back” even pressing harder material like PS. So for cost saving : just a straight sticks and no bearing. -> The screens / sieves will be simplified : reduction of the thickness to 4mm + bending line. The screens will be able to be manufacture without bending or rolling machine, only laser-cut and welding. -> Also screen holes will be reduces to 12mm (there were 20mm in the video), this should give smaller flakes with a still acceptable throughput. Smaller holes will have too much impact on the productivity, and as said @PlasticAtBay_Julien_NScotland having a shredder that also granulate is utopic, so we are staying on the shredder side, there is already a lot of good and cheap granulator out there.

Yesterday we went to the K 2022 in Düsseldorf to see it in Person. We asked a WEIMA guy when we can buy one and how much the estimated retail price might be. He didn’t even know what Precious Plastic is and said he can’t tell us anything about the machine. Weima is not going to produce it, it was a »one time job for a customer«. Then he made some remarks on how pathetic the approach is and left us standing there. I was quite shocked by this response. Nonetheless: it looks really good! I’d love to have it in our workshop.

steffen

Yesterday we went to the K 2022 in Düsseldorf to see it in Person. We asked a WEIMA guy when we can buy one and how much the estimated retail price might be. He didn’t even know what Precious Plastic is and said he can’t tell us anything about the machine. Weima is not going to produce it, it was a »one time job for a customer«. Then he made some remarks on how pathetic the approach is and left us standing there. I was quite shocked by this response. Nonetheless: it looks really good! I’d love to have it in our workshop.

Weird ! I was there at the beginning of the fair, but couldn't stay the whole time. There was a lot of Weima sales people at the fair, and they are not well aware of the project (it is a relatively big company, and this is a relatively small project for them). I think you had bad luck and talk to one that was not very interested by the project, in general they were quiet happy with the result.

But that bring us to a little update ! Weima finish the second version of the machine, that is now very close to its final version : the pusher system have been simplified and the hopper have been built with safety requirement in mind. Now we will go to the 3rd and final version, mostly focusing on cost optimisation (homogenisation of the sheet sizes, cheaper motor and reduce the amount of bolts) : material cost should be around 2500 - 3000€ (considering the new price of everything), which should give a selling cost around 6-7000€ probably for people producing it. Then we will have some extensive testing to determine the output depending on axis type / plastic type / screen size... By the end of the year / beginning of next year the machines drawings should be ready !

10:47 AM

Concerning the production, the guy was right, Weima is not interested in selling them, this project was to support us designing and having a new open-source shredder PRO. They will probably produce some part, like the monoblock rotor, that can be sold on the bazar (there will also be a laser cut rotor, so people have choice), but this machine is too small compare to what they usually produce / sells. So it will be on the exisiting community for the production. (edited)

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hi, A motor/motoreductor supplier just advised me to put the motoreductor without coupler directly on the axe of the shredder, did anyone tried this on the 3.3 ? is there any risks ?

This is what we are doing on the new version of the shredder PRO. But on the shredder 3.3, the shredding box and the motor are linked together by a frame, meaning there is a high chance for these two to be slightly misaligned to each other. The coupling we use (HRC) can accept a slight misalignment, the axis straight in the motor will not.

10:16 AM

So, it is possible, but it imply a serious redesign, where the shredding box also need to support the motor, and only the shredding box can be attached to the frame to not create a over constrained structure.

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fecarian

hi, A motor/motoreductor supplier just advised me to put the motoreductor without coupler directly on the axe of the shredder, did anyone tried this on the 3.3 ? is there any risks ?

You can do it. I don't recommend it. We have gearboxes that take through shafts and we've replaced several shafts due to shearing. Keys can roll destroying the shaft. It makes replacement a pain in the butt. A Lovejoy could make replacement much easier and the spiders allow for slight misalignments. Basically it comes down to room. If you can fit a coupling on there I suggest doing it. If you absolutely have to take up as minimal space as possible connecting directly to the shaft can be done. It just makes repairs more of a headache.

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You can see some testing of the first prototype of the shredder happening here

the video was filmed in September, we already made a second and more safe version, more details coming soon ! https://youtu.be/on1lUU_QAxs (edited)

Precious Plastic

This shredder will change the recycling game

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Where to source those milled teeth?

The milled teeth are machine by Weima, but there will be 2 rotors on the final model, a classic laser cut blade, and another, similar to this one, that can sourced at Weima, and with off the shelf cutting teeth.

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https://youtu.be/PazKSWlWLvM

Alex recycles and creates

My Shredder #preciousplastic #machine

Hey everyone! I’m based in the northeast USA #🍔north-america and seriously considering a shredder for a small scale project. I’ve not seen pre fabs or kits made in the states and the shipping from abroad seems exorbitant. Anyone in the US have any experience using the plans for the shredder or shredder pro with a US fabrication shop who could help me to (roughly) estimate costs and complexity? Or any challenges I can expect to run into?

perispective

Hey everyone! I’m based in the northeast USA #🍔north-america and seriously considering a shredder for a small scale project. I’ve not seen pre fabs or kits made in the states and the shipping from abroad seems exorbitant. Anyone in the US have any experience using the plans for the shredder or shredder pro with a US fabrication shop who could help me to (roughly) estimate costs and complexity? Or any challenges I can expect to run into?

Have you checked machine shops close to you on the map?

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CitSciWorkshop

Have you checked machine shops close to you on the map?

I see one - gonna try reaching out to see if they’re still actively involved in the community/project.

CitSciWorkshop

Have you checked machine shops close to you on the map?

No replies. Trying someone else local-ish who mentions they have a shredder to see what into making it. There aren’t any more machine shops listed near me (I’m in NJ, only other close ones are in Ohio and Toronto, Canada).

Yann

The milled teeth are machine by Weima, but there will be 2 rotors on the final model, a classic laser cut blade, and another, similar to this one, that can sourced at Weima, and with off the shelf cutting teeth.

Hello, I checked trough the documentation, and wondering if pushing the levers are easy, it should have only one handle, what pushing both sides, would be more comfortable and need a simple mechanism. Also, I'm wondering if this could have the cutting area ofsetted like on one side to 30-45° and then have a single screen coming from the other side with the mechanism, basically reaching again the state of operating with a single lever instead of 2, also pieces might fall trough screen more easy and if you design it well the counter knife can be removed from sideways The bearings on the levers are probably overkill, brass bushing would suit there. Shieve could be an hexagon octagon shape cutted in half, where you make the actual screen from flat pieces and the frame from L beams or something similar, and fix the shieve to beams with 4 or 6 M4 CSS allen screws

Sastas

Hello, I checked trough the documentation, and wondering if pushing the levers are easy, it should have only one handle, what pushing both sides, would be more comfortable and need a simple mechanism. Also, I'm wondering if this could have the cutting area ofsetted like on one side to 30-45° and then have a single screen coming from the other side with the mechanism, basically reaching again the state of operating with a single lever instead of 2, also pieces might fall trough screen more easy and if you design it well the counter knife can be removed from sideways The bearings on the levers are probably overkill, brass bushing would suit there. Shieve could be an hexagon octagon shape cutted in half, where you make the actual screen from flat pieces and the frame from L beams or something similar, and fix the shieve to beams with 4 or 6 M4 CSS allen screws

I'd like to see the contact levers foot activated, allowing the application of body weight rather than arm strength, and leaving hands free to engage the emergency stop.

I have a question, im about to buy the motor for the V2 shredder, how much power is reccomended? The place where ill buy from said half hp is more than enough, but i rather ask you folks

Mosk17

I have a question, im about to buy the motor for the V2 shredder, how much power is reccomended? The place where ill buy from said half hp is more than enough, but i rather ask you folks

3hp (2.2kw) for shredder 3-5hp (2.2-4kw) for shredder pro 1/2hp is too low. Your output rpm would have to be incredibly slow for it to work without jamming all the time.

It will have 56rpm

7:17 PM

I’ll ask then for a more powerful one then, thank you

hey guys, I've got a shredder 2.1 with a 3hp 1 phase motor. it works decently but with anything larger than a couple inches it is always stalling. I'd like to eventually implement some arduino control but for now I designed another version of this shredder that has smaller teeth, so it can hopefully just nibble away at big parts and not stall out. Check it out and please share your feedback. https://github.com/hazyavocado/Shredder2.2

GitHub - hazyavocado/Shredder2.2: Shredder with small teeth to nibb...

Shredder with small teeth to nibble away at big parts - GitHub - hazyavocado/Shredder2.2: Shredder with small teeth to nibble away at big parts

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1:20 AM

by the way, i am using something like this to limit current to around 10 amps, and also using it to turn on/off. https://www.aliexpress.us/item/2255800859985978.html

sodadiet

hey guys, I've got a shredder 2.1 with a 3hp 1 phase motor. it works decently but with anything larger than a couple inches it is always stalling. I'd like to eventually implement some arduino control but for now I designed another version of this shredder that has smaller teeth, so it can hopefully just nibble away at big parts and not stall out. Check it out and please share your feedback. https://github.com/hazyavocado/Shredder2.2

Looks good! I'm curious how it runs so let us know if/when you do this. I have a shredder box that needs new blades anyways so.. If it works better, I'm game.

Ben - Precious Plastic Ciledug

Looks good! I'm curious how it runs so let us know if/when you do this. I have a shredder box that needs new blades anyways so.. If it works better, I'm game.

Thanks, I’ll let you guys know. I made a few versions with different shapes for the fixed blades. Check the other branches. I’ll probably build the flush straight blade version : https://github.com/hazyavocado/Shredder2.2/tree/flush-straight-blades

GitHub - hazyavocado/Shredder2.2 at flush-straight-blades

Shredder with small teeth to nibble away at big parts - GitHub - hazyavocado/Shredder2.2 at flush-straight-blades

what if the center blade is just a series of 200mm circular saw blades similar to how Jeremy fielding did in his video? but obviously turning at a slower speed.

any news on if the Wiemar shredder design will be released? I have buyers for tis specific design

I will make a little recap, but basically the development slowed down during winter. The 3rd and final version is currently being built, then with documentation and testing we should expect a release in June-July probably.

I found an electric winch

10:56 AM

I am wondering if this is minimum enough to power a shredder

If I believe it might have some torque with this gear ratio, this is still far underpowered for a shredder.

I have order this motor for the shredder

11:49 AM

Will this work

11:50 AM

And if I get this kind of gear box

11:50 AM

11:51 AM

Will it work with the motor

11:51 AM

To reduce from 900Rpm to 30rpm?

foofred

To reduce from 900Rpm to 30rpm?

That’s that ideal RPM also your motor has to be able to run forward and backward

Alex_recycles and creates

That’s that ideal RPM also your motor has to be able to run forward and backward

Can you say the motor and gearbox will work nicely together. ?

foofred

Can you say the motor and gearbox will work nicely together. ?

Yes they do

4:07 PM

You want the shredder to be slow and powerful

Thanks

And make sure the motor

4:08 PM

Can go forward and backward

4:09 PM

I think you can upgrade a motor so it can do that

foofred

I have order this motor for the shredder

@Alex_recycles and creates this is a 3 phase motor. You simply swith two phases for it to work in reverse. Forward: L1, L2, L3 Reverse: L2, L1, L3 If you only have single phase power available, you'll need a VFD.

5:02 PM

It doesn't appear that the motor will mount directly to the gearbox. I suggest finding a motor that mounts directly to the gearbox, otherwise you're going to have to figure out how to mount the motor to a frame and also to the gearbox.

Hey. I would like to build a device on top of 3.3 shredder, that is more compact than original - something that 3d printing nerds like me can put together easily using off the shelf components and won't take too much of the space. Ideally I would like to:

Get rid of the coupling between gearbox and the shredder body, and (potentially) remove one of the bearings supporting the shredder's shaft. This has a potential to reduce the width by 36% (53->34).

Remove the need for the frame.

The way I think about it is to screw together the shredder body and the gearbox. Now I am concerned about a couple of things:

Safety role of the coupling. In the original design it's likely it will fail first if too much torque is applied. Here, my strategy would be to use a servomotor with an arduino that does the torque limiting. How reasonable is that?

Tolerance of the gearbox for radial / angular misalignment between the shaft. I guess I can get it as accurate as 0.15mm, but I have no idea if this would be within the range of what gearbox can live with, would you?

1:19 AM

I also realized that 3.3 unit's shaft (30mm) does not match off-the shelf gearbox sizes (RV50 - 25mm, RV63 - 25 mm, RV75 - 28mm). Without the coupling this would make it difficult for home tinkerer to source the necessary elements - likely requiring custom machining (expensive, and takes time). So I thought about modifying the 3.3 design to reduce the output shaft size to 25/28mm on the side that would mate with the gearbox. With this folks can use PP's bazaar to source the shredder unit and can order standard sized gearbox easily. My question here is: how much thought/process went into sizing the shaft? Is the 30mm backed by some calculations / FSM simulations (if so, would love to see those), or just practice of what worked in the past? I.e. how much would I stretch the design by shaving it to 25/28mm? I wonder if you would have any thoughts on these ideas? Possibly is it something that was tried/considered before? A bad/good idea? Anything I should think about? If this goes ahead, would you like to share to distribute the design under PP brand? I'm happy to license any work on it open source. Disclaimer: I know nothing about mechanical design, I'm just a programmer that knows how to bolt things together.

Flexible shaft couplers are very common, and you can get them with one size on the input and a different size on the output. With as much vibration as you will get from the blades coming through the shaft, I think it's a good idea to have some type of dampening isolation from the shaft to the gearbox, regardless of the precision you have in mating them. That is just speaking in general, I would have to take a closer look at 3.3 to give you a specific advice

Yann

You can see some testing of the first prototype of the shredder happening here

the video was filmed in September, we already made a second and more safe version, more details coming soon ! https://youtu.be/on1lUU_QAxs (edited)

any updates here? couple questions, these are carbide cutter inserts like from a lathe? what rpm is this running? The screen itself is acting as the anvil to work the cutter against? or you are relying on speed to cut without any sort of anvil?

MaciejW

Hey. I would like to build a device on top of 3.3 shredder, that is more compact than original - something that 3d printing nerds like me can put together easily using off the shelf components and won't take too much of the space. Ideally I would like to:

Get rid of the coupling between gearbox and the shredder body, and (potentially) remove one of the bearings supporting the shredder's shaft. This has a potential to reduce the width by 36% (53->34).

Remove the need for the frame.

The way I think about it is to screw together the shredder body and the gearbox. Now I am concerned about a couple of things:

Safety role of the coupling. In the original design it's likely it will fail first if too much torque is applied. Here, my strategy would be to use a servomotor with an arduino that does the torque limiting. How reasonable is that?

Tolerance of the gearbox for radial / angular misalignment between the shaft. I guess I can get it as accurate as 0.15mm, but I have no idea if this would be within the range of what gearbox can live with, would you?

i use a chain flex coupling, 2-3mm misalign and it still works. I would not depend on the motor bearing to save money. bearings are cheap. less than 10usd for Chinese and 30usd for the good euro or japanese brands. i thought bout modding the shredder box to the v3 to connect a hoist in it, but it comes out to a lot of work for no gain, vs just using the existing v3 design, pulling the hex shaft out of the shredder (25mm) machining it down to one inch round with a proper key and putting it back together. I spent years thinking bout the v3 and making it lower cost and at this point this is as good as you will get. Also NO SERVO. Servos are very expensive. adding in electronics etc just goes in the opposite direction for cost. keep it simple, robust, cheap and dumb with the shredder design. Spending 500 dollars to save on 100 in materials is not the direction to go. Been there done that.

foofred

Click to see attachment 🖼️

it will overheat. it will shred, but only a few minutes. then you will either have to stop or it will burn out if there is not overheat protection

@Butte (PP Philippines) The idea of removing the bearing is to reduce the dimension by allowing the gearbox to mate directly with the shredder wall. No intention to save money, but to make the device as compact device as possible instead. I frankly would spend a bit more on the shredder to make it smaller - where I live the cost of the device dwindles in comparison with the real estate costs to house a full floor standing unit. But the added cost for going with servos isn't in the range of 500 usd, I think. I can get 1kW servo with an AC driver for approx 220 USD delivered (check Lichuan brand on Aliexpress). Arduino, wiring, microswitches for safety, shouldn't go excess of 20, maybe 30 if display is added. Electronic housing, hopper - self 3d printed. So it doesn't bloat the cost that much, given a cost of comparable "dumb" motor and removed parts (bearing, frame). The point on complexity is also good, but I'm happy to absorb it (software, electronics design). There are very few commercial alternatives available for that niche, but the ones that are there charge in excess of 1500 (Polystruder, Fefil). I think the budget for an open source machined based on very slightly modified (and as such - easily available) 3.3 shredder can be as low as 700-800 (300-400 shredder, 250 servo, 100 gearbox) usd. I suppose using 1 kw servo with a 3.3 unit that IIUC can deal with much stronger motors is going to grossly underutilize the shredder. But that's ok for the target niche, and the benefit of availability of 3.3 via bazaar is huge.

MaciejW

@Butte (PP Philippines) The idea of removing the bearing is to reduce the dimension by allowing the gearbox to mate directly with the shredder wall. No intention to save money, but to make the device as compact device as possible instead. I frankly would spend a bit more on the shredder to make it smaller - where I live the cost of the device dwindles in comparison with the real estate costs to house a full floor standing unit. But the added cost for going with servos isn't in the range of 500 usd, I think. I can get 1kW servo with an AC driver for approx 220 USD delivered (check Lichuan brand on Aliexpress). Arduino, wiring, microswitches for safety, shouldn't go excess of 20, maybe 30 if display is added. Electronic housing, hopper - self 3d printed. So it doesn't bloat the cost that much, given a cost of comparable "dumb" motor and removed parts (bearing, frame). The point on complexity is also good, but I'm happy to absorb it (software, electronics design). There are very few commercial alternatives available for that niche, but the ones that are there charge in excess of 1500 (Polystruder, Fefil). I think the budget for an open source machined based on very slightly modified (and as such - easily available) 3.3 shredder can be as low as 700-800 (300-400 shredder, 250 servo, 100 gearbox) usd. I suppose using 1 kw servo with a 3.3 unit that IIUC can deal with much stronger motors is going to grossly underutilize the shredder. But that's ok for the target niche, and the benefit of availability of 3.3 via bazaar is huge.

thats your materials cost of 700 to 800? My v3.1 is only around 300usd with a 3hp hoist motor...

@Butte (PP Philippines) Have you laser cut / welded this yourself? Shredder unit kits alone are 300-400 on bazaar, with a finished kit like yours going for > 2000. Hard to build them at material cost in DIY setting without an ability to machine steel and weld.

Butte (PP Philippines)

thats your materials cost of 700 to 800? My v3.1 is only around 300usd with a 3hp hoist motor...

Does the nice doggo come with the unit?

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MaciejW

@Butte (PP Philippines) Have you laser cut / welded this yourself? Shredder unit kits alone are 300-400 on bazaar, with a finished kit like yours going for > 2000. Hard to build them at material cost in DIY setting without an ability to machine steel and weld.

yes actually I have built and sold well over 200 units of v3 shredder kits, 24 units of complete v3 shredder with gear motor, plus another 30+ units with 5hp motors in the last 5 years, and I have a full fabrication shop. I get laser cutting locally, 6kw fiber laser. I also have a CNC plasma in the shop. All built from Precious Plastic sales. We we have 10 full time employees. Started out in my home garage with zero money, just some tools, and a obsession with building Precious Plastic machines. https://youtu.be/Hk7Ay_pigVA (edited)

Precious Plastic Philippines

July 3, 2023

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HAL_9000

Does the nice doggo come with the unit?

that is Adogbo (rymes with adobo) He is a employees dog. this is the old shop. New shop dog is Rex and our office cat is Mister Black.

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MaciejW

@Butte (PP Philippines) Have you laser cut / welded this yourself? Shredder unit kits alone are 300-400 on bazaar, with a finished kit like yours going for > 2000. Hard to build them at material cost in DIY setting without an ability to machine steel and weld.

our finished v3 shredder is 865USD local price including VAT.

1

@Butte (PP Philippines) would you be willing to make a prototype of the shredder unit I discussed above? Basically a v3 module with a) shaft turned at one end to match the gearbox interface (25 or 28 depending on standard gearbox) and possibly shorter and b) some mounting holes in the side wall countersunk from the inside, to match the gearbox flange threads. I'm happy to do the CAD for the parts. That said I am still not sure if that's a good idea from mechanical perspective. I read your concern about vibration. The cost of the servos feels like a valid trade-off for added control safety and compactness, at least for the use case I intend to use it for and given the volumetric cost of the ownership.

MaciejW

@Butte (PP Philippines) would you be willing to make a prototype of the shredder unit I discussed above? Basically a v3 module with a) shaft turned at one end to match the gearbox interface (25 or 28 depending on standard gearbox) and possibly shorter and b) some mounting holes in the side wall countersunk from the inside, to match the gearbox flange threads. I'm happy to do the CAD for the parts. That said I am still not sure if that's a good idea from mechanical perspective. I read your concern about vibration. The cost of the servos feels like a valid trade-off for added control safety and compactness, at least for the use case I intend to use it for and given the volumetric cost of the ownership.

i really do not have the production capacity at the moment. hunting for a engineer to do cad documentation on the double shaft v3 and the baling machine

ive got a bit of a curiosity regarding shredders, grinders and granulators for recycling plastics. my curiosity is thus: what are the differences between the three and what are the pros and cons of the three. im hoping to start a recycling facility soonish and im trying to look into as many various options as possible to make sure i can get the most out of my investment (edited)

collosis

ive got a bit of a curiosity regarding shredders, grinders and granulators for recycling plastics. my curiosity is thus: what are the differences between the three and what are the pros and cons of the three. im hoping to start a recycling facility soonish and im trying to look into as many various options as possible to make sure i can get the most out of my investment (edited)

https://www.sinoshredder.com/shredder-grinder-and-granulator-difference/

waterppk

https://www.sinoshredder.com/shredder-grinder-and-granulator-difference/

ive seen that page and quite a few others. im thinking im probably going to try to make a grinder like the "game changer" video from precious plastics but without a schematic or anything like that its gonna be difficult to get it going

Yann

You can see some testing of the first prototype of the shredder happening here

the video was filmed in September, we already made a second and more safe version, more details coming soon ! https://youtu.be/on1lUU_QAxs (edited)

any ideas as to whether or not the schematics for this and the upgraded version will be released in the future?

collosis

any ideas as to whether or not the schematics for this and the upgraded version will be released in the future?

Unfortunately working with a external company has its big advantages : a machine properly designed by engineers with decades of experience, but it also come with some slowness. Normally we should receive the final prototype from Weima at the end of this month, and from there we will work on the documentation and the videos.

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Butte (PP Philippines)

any updates here? couple questions, these are carbide cutter inserts like from a lathe? what rpm is this running? The screen itself is acting as the anvil to work the cutter against? or you are relying on speed to cut without any sort of anvil?

The carbide inserts are standard pieces that can be bought to different supplier. We will also get some big batch manufactured to be able to put them on the bazar to make them more accessible (like for the extrusion screws at the beginning). The shredder is designed for 50 to 60rpm, so not relying on speed to cut. There is a fixed blade under the axis where the cut is happening, the screens act as pushers to ensure the plastic is forced against the axis and brought to the fixed blade.

For all practicality when developing your plastic shred line, and to go big, or even practical to process a couple hundred kilos daily, you need a multi stage shredding system. First step after sorting is to run thru a dual shaft shredder. These are ideal to break down big stuff into smaller, but is not effecient in granulating down to the sub 6-10mm flake that our extrusions work with. After the initial shred, then it should pass thru magnets to remove steel particles. Next step is the granulator for the final shred, and ideally another set of magnets, then vacuum collection, to a cyclonic filter, and bagging or silo. somewhere along the way a washing line and de-watering system would also be nice but not exactly required.

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@Butte (PP Philippines) you've specifically mentioned a dual shaft shredder. How does a single shaft shredder like v3 relate to that?

MaciejW

@Butte (PP Philippines) you've specifically mentioned a dual shaft shredder. How does a single shaft shredder like v3 relate to that?

my dual shaft shredder re-uses all the parts of the v3, only the side plate is changed and 2 gears are added.

@Butte (PP Philippines) is dual shaft better design by principle, or simply - more the better?

dual shaft is better. How ever it would require a 3.5 HP motor cause your moving more parts. A single shaft motor would require 1.5 HP motor

Alex_recycles and creates

dual shaft is better. How ever it would require a 3.5 HP motor cause your moving more parts. A single shaft motor would require 1.5 HP motor

im using 5hp and even then it still jams on the bigger stuff. I have run up to 12hp diesel on the v3.

Butte (PP Philippines)

im using 5hp and even then it still jams on the bigger stuff. I have run up to 12hp diesel on the v3.

do you have a gear box attatched ?

I use belt and pulley to a jack shaft and then chain and sprockets for the second reduction because of the torque.

gear boxes can increase the torque by a lot but the RPM will be decreased

Alex_recycles and creates

gear boxes can increase the torque by a lot but the RPM will be decreased

a set of belt and pulley can do the same thing as a gearbox

1

Does anyone know where i can get the plans to build the shredder?

1:06 PM

Also, hello everyone. Glad tl be here

themazz

Does anyone know where i can get the plans to build the shredder?

The plans are in the download section: https://community.preciousplastic.com/academy/download otherwise at the left side you can walk through the various machines in "Build"

Precious Plastic Community

A series of tools for the Precious Plastic community to collaborate around the world. Connect, share and meet each other to tackle plastic waste.

2

are we thinking wrong about our shredder design?

4:38 AM

I am seeing shredders with carbide tooth inserts.

4:38 AM

my local milling supply has these for a little less than 3 USD each.

1

like this?

5:22 AM

So IMHO to have a cheap consumable insert the design/cost of the tool holder is super expensive.

i could laser from 12mm ms plate the holder, then drill and tap it...

So if you have 3 inserts per blade that is 3x setups and 3x tool changes....per blade.

8:55 AM

At a machinists rate that is a massive labor cost

8:55 AM

Again, IMHO

Butte (PP Philippines)

are we thinking wrong about our shredder design?

It depends on how you're thinking about the shredder use;

if you're looking at it as an industrial paced business machine, replaceable carbide inserts make a lot of sense.
if you're thinking about it as an occasional use hobbyist machine, keeping the costs & maintenance as low as possible (to ease entry into the space) makes more sense. There's nothing wrong with either option, it depends on how you're going to be using the machine. Both have their pros and cons.

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Butte (PP Philippines)

my local milling supply has these for a little less than 3 USD each.

How mady do you reckon for a full set?

36 if i was to retrofit my granulator

https://youtube.com/shorts/rv1uL9sUBuM?feature=share going to send this configuration of shredder in the wild after a shield for the gears is added. i kept having the bearings break because of the previous configuration of the gears, this is only good method unless I was to use one motor for each shaft.

Precious Plastic Philippines

sachet dual shaft

Hello all! We run a 3D printing business and are building up quite a bit of PLA filament waste as well as empty filament spools. I would love to build a shredder to break down the material to smaller chunks for melting and then machining on my CNC router. Can any of the Precious Plastic Shredder builds handle large (less than 6" round) PLA chunks? Nothing I print is solid, generally 3-5 walls and 15% infill. I would also love to build this myself, but am not sure what the technical specs need to be to shred something like this.

We were trying to shred 3D printed parts with the single axle shredder (looks like: https://bazar.preciousplastic.com/machines/shredder/shredder-kits/precious-plastic-shredder-box-stainless-steel-material-minor-modification/) and it would stall pretty readily but our parts are pretty dense. We ended up getting a surplus 5HP granulator and it's still possible to stall that but only if you dump in a box of stuff at the same time. I know this won't help you a lot but I think about the only thing you could do is get some of your prints to someone with a shredder for a test or find someone nearby you that you could bring your parts to test

4:49 PM

I think the spools are polystyrene FYI so that might be a problem for reuse, the ones we've had aren't marked/labelled for a material

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