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V4 Shredder Double Axis – [INDEX+BLOG]

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Yann lagrenouille

V4 Shredder Double Axis – [INDEX+BLOG]

23/04/2019 at 15:49

Hey community,

We are 3 guys to work on the V4 shredder double axes, Landry ( @landry) from France – a industrial designer and engineer, Paco ( @pacoacu13) from Spain – mechanical engineer, and Yann from France – material engineer.

We work on the Precious Plastic shredder double axes in Eindhoven, and we try to find the best solution for shred some big parts of plastic, also including thick parts like beams and sheets.

The sub-topics will be the same than for the single axis shredder, as most of the technologies will be similar :
Drives (Motors and Gears)
Cutting Technology (Shredding principles and fine tuning)
Feeding System (Hoppers, Conveyer Belts, new Systems)
Control System (Electronics)

The double axes shredder is the most used for different industrial activities, but with different designs for different results. We need something close to an industrial shredder, who can shred different plastic shapes and sizes quickly, and easly in very little plastic chips.

Reliability, Safety & Maintenance
As for the single axis shredder trials, the next version should not jam as often as the current shredder does. Furthermore we want to implement automatic reverse (torque detection) and back to normal operation.
Safety will also be improved by a proper hopper limiting the acces to the blades, and a good “catch” of the plastics for removing any human help in the process of shredding.
Maintenance such as cleaning (between different plastic batch) shall also be considered.

So how will we start?
The main goal we want to achieve, is increasing the shredding capacity, we want something much bigger than the last verion, and that can work all day (at least 7 hours) with no jam and very few human interventions.Our biggest problem right now is the huge variety of plastic that can be found – small/big, thin/thick, flat/geometric and different materials. And most of the shredders are specified on one particular task. E.g. slow running Granulators to recycle runners of the injection process.

Double axis shredders in general seams a very polyvalent option, even if they have quiet some incovenient (like a lot of laser cut parts…), but let’s give it a try at least !

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24/04/2019 at 12:58

yeah, of we course we want 🙂 major problem we notice over and over is that people take v3 as granted and a sort of single source of truth, we have a often hard time to explain our changes to the design to users … so lets do the next as economic as possible 🙂

24/04/2019 at 12:50

if you guys can upload a drawing at some point would be great, I can show this to our gurus who do machine building/upgrades/maintenance for a living, since 40 years. Details become quickly an issue. For instance if you base your design on holes, it just invites a lot of problems (ie: not using bolts with the right hardening grade,..), also if you make a template for production, sometimes we use the CNC to mark holes. Marking holes alone is kinda difficult even for more experienced guys (i do this only since 2 years) like me, for students with sight problems things go quickly banana. I prefer good welds over holes, it goes faster and I don’t expect a John Doe to open and maintain those machines 🙂

24/04/2019 at 12:42

No worries, I just wanted to say that yes, this shredder will be bigger and in another price range for sure, as we want to have this alternative. Also this will be a parallele development with the single shaft, only one will probably be released at the end.

Therefore I am and will be very thankfull for all your inputs to make it easier to built, cheaper, more efficient… if you would like to of course.

24/04/2019 at 12:26

thanks Yann, yeah, didn’t want to appear piggy again, just throwing numbers and observations at you, collected here downtown in the garage 🙂
go ahead. i also wanted to highlight what impacts design decisions may have, a tiny a little detail can render us unable to deal with production in the short times we can spent on one built.

24/04/2019 at 00:18

lol, hilarious, evtl. we take this offline but yeah. I am surprised one can manage to get enough plastic at all from the dumpster (here in eu, going to 80% recycled), sort, wash and then make a product. considering the $$ and energy thrown at this first tedious .. smelly stage, I am not surprised we’re not there yet . From my observations all over the net, I think 10% make it, somewhere into a new profession, luck and cool products. There is and was so much creative & successful entrepreneurship on the 3D print train. I’d burst out in happy tears to seeya all there catching up; speaking of technology; so it’s a matter of time that labor is reduced to a minimum due to automation – something we can do too – (a dark transition age), why not copying the idea of automation and go for micro [email protected], so much to do yet, so much to gain 🙂

23/04/2019 at 23:06

thanks @s2019, honestly, haven’t even got that far figuring those questions, obviously. I have often the sensation that the shredder should be dropped for good and all efforts & resources should rather focus on the ‘after math’ of this very first stage of material development which accounts easily up 80% til shipping a great product. I mentioned this already somewhere but got no good feedback but here again: why not just grabbing the plastic after sorting, washing, shredding right from the facility ? this way one can focus on a product with way less pollution, footprint, etc … time will tell, v5 will tell 🙂 Imagine that PP provides a low-cost semi/full-automatic machine which can produce somewhere in a shelf new parts 🙂 they will be small but still, one can make a decent living from it, right away, no hassle or 2-5K invest needed …
thanks man,

23/04/2019 at 19:28

btw. here the prices for making v3 work :

2.2Kw = 420 Euro for the motor & reducer, 130 Euro for the inverter, 30 Euro for
cables, 100 Euro for couplings  = 680 Euro

4Kw (our recommendation to go bigger) = 760 for motor and reducer, 220 Euro for the inverter, ~40 Euro for wiring,breakers, emergency switches , 160 for couplings = 1175  Euro

and that’s the more cheap variant you can possibly get in europe, especially if you can’t risk anything (warrenty, invoice, safety rules out scrap yard parts). i don’t think any of the machine builders on the bazar are picking this on a daily base from the scrap yard, how could you ?

23/04/2019 at 19:00

we already tried everything possible but eindhoven seems to use it’s goal keeper position to deny/refuse any sort of improvements, no matter the gravity or urgency or realities coming with it. anyway, don’t worry, we started building a new site pointing out all the numbers/fixes for v3.

What’s really buffing us now since long how we got from ‘precious plastic’ doable with ‘common available tools and materials’ over to  recycling bigger quantities, eg: reinvent the wheel and copy industrial grade machines in the garage, etc.. We serve a good chunk of the european users who also have the $$ to throw at this kind of activity. I can only remember a few clients who needed such ‘mega’ machines, but ok, apparently I didn’t get the memo about ‘mass plastic for the mass’, lol


23/04/2019 at 18:38

yeah, i just checked,  it’s around 2-3K to make in a good equipped shop, plus income tax and vat = around 4500 – 7000 Euro. And that are prices for a place, catalonia, which had 4+ industrial revolutions behind and I’d say the prices here are still quite cheap. Most of the things here are produced on a ‘shop to shop’ base, depending on ‘external’ components like high quality blades from Alibaba makes this a really tough adventure to get out to people 🙂 We already struggle with the cashflow constraints given by the bazar modalities ..

good luck, I’d honestly prefer the v4 team fixes the past first, that’s a ballpark most of us in the PP machine builder segment can handle !

23/04/2019 at 18:11

@sharma-sagar, you could laser cut it or produce it on the lathe (i hope) and some exorbitant welding and/or plasma cutting. doing this however in a homeshop (professionals in that segment are busy with more profitable stuff) is quite a challenge, an pretty expensive one. getting the hexbar already dialed precisely in on a pretty strong lathe for this design for instance will need quite some ‘special’ equipment, a good 4 jaw chuck. however, I estimate the production of this build around 2000-3000 euro (if you want a ‘sustainable’ activity around PP, with after being 40+ old ). So this would be around +1000 Euro more than the competition which does the thing with the double – triple strength, quality and experience …. That would address the needs and wallets of around 10% of users we encountered til now.

however, from what I see , I can just hope this drive shaft isn’t below 3cm diameter, again … this would rule out also stronger motors

btw. whilst you on it, Is there a reason why nobody updates v3.0 first with all the issues and fixes reported here ?

If you like I can show the design to some professionals (seniors) to get some remarks, for free, before we all blow another 30 tonnes of precious resources on this subject 🙂

23/04/2019 at 17:30

Is it as powerful as it looks? Are the parts still lasercut?

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