Share your shredder info!
I am a Mechanical Engineering student from Brazil willing to build a shredder for my thesis work.
One step of my thesis work is benchmarking.
WIll you please share your shredder information for my research?
It will be shared with the community after the work is done!
Please answer me with:
– Photos of your shredder
– Dimensions (height, length and width)
– Motor specifications
– Production cost/Selling cost
I believe this topic will be useful for many people afterwords!
Hi Adele, the cost depends on the country you live I think you will start asking to a laser cutter company the cost sending them the files that you find on the PP download kit (I buy it at 340 euros complete) , than you can ask for the motor reducer In that case I can suggest you that is sufficient a 1100w mono phase with 28 rpm or a 750w with 17 RPM but the costs is almost the same(about 370euros) and the weight too. For the frame cost it depend on the material you can ask for steel frame or for extruded aluminium like the one I use, in this case the cost is about 150 euros.
Is 28 or 27 rpm fast enough? I read 70 rpm was ideal?
It is fast enough and allow you to use just, a 1.1 KW motor, so cheaper and lighter than a 2.2 KW, you can use a 47 rpm but you will need more power (1.5 or 1.8kw), as you, can see in many videos when the speed is too high the bottles jump up and they don’t be shredded, you need something to push them, instead with 28 rpm I rare this appens.
it seems the torque (strength it can supply the schredder axe) of the motor is a bit low; i would rather go for at least 200N/m
Concerning the RPM; you should keep in mind that 60rpm = 1 full rotation / second (which in my opinion is already fast enough !!)
to complete my explanation : the torque is calculated with the values of Watts & RPM.
A reducer will slower the RPM whilst maintaining the same W value, which will make the torque value go higher
hope it helped !
Maybe time to drag this back up:
This motor/gearbox combo will actually produce around 225Nm max, but it may be that the gearbox is only rated for 73Nm. Generally they will take several times the rated load before failing, but prolonged heavy use will shorten its life.
there is already a post with lots of info about this topic. according to the reports, 2.2 kw is the base line for most house-hold plastic, anything beyond (industrial waste, but precious since its mostly good quality) will jam your shredder pretty easy.
btw. it also depends you’re running this motor with 3 phase which is by nature more powerful.
4kw however gives you sufficient and efficient power (rather with new reducer) but kicks you into the 700-1200 Euro range, rarely jams, good for 24/7 operations.
please search the forum for ‘share your shredder experience’ or so.
seriously, having spent myself dozens of hours filling the shredder, i wouldn’t even bother to use anytime below 7kw next time. you need a good amount of plastic chips for the next steps : sheet press, injection, extrusion or vacuum to make this on a regular base. especially when plastic recycle machinery have a hefty pretty tag, you’re likely up making bigger things just, easier to get those machines, build or purchased, imho.
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