Injection machine revamp

Precious Plastic Machine Development
#1

Hi There,
i have been involved in my shredder making and i have finished an injection machine.
attached the one i have made out from a jack.
simple enough and easy to cover all the enquiries i have from customers asking these machines for simple projects.
i am thinking of adding a motor to ease the feeding process.
it would involve a ultrasonic sensor(i guess) and an arduino.
i just have to find out the power that the motor should be able to give.

any one here to help me to choose the right components? elaborate the program ?

the process on the arduino should be roughly this one :
– cold extrusion prevent
– distance measured <20cm
-go up
-distance measured =0
-go down
– distance meaured  = 20cm
– go up
…

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#2

And another picture

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#3

hi Stan
thanks for your message! very nice.
it is a 1300w – 50rpm winch motor. it delivers about 250Nm torque.
very easy to use and safe with the doglead.
it is powerful enough to shred hard plastics such as vacuum cleaner cases and others.
main problem is that it has a limited shredding duration.
but in most cases 30 minutes is enough.
very noisy process.

#4

Looks great. The injection machine looks like a convenient alternative to the PP design.

What was the lift and power rating on the winch motor/gear you are using?

Great work.

#5

and here is the “shreddinjection” machine.
easy to fit on the shredder chassis.
well balanced if placed at the opposite of the shredder
on wheels to melt plastic outside.
injection jack in on a sliding rail to accomodate any kind of molds.
jack can be driven using cordless drill
handle can be dismantled easily.

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#6

here is the final version with small modifications only !
i have a push bar to help the flow, and extensions in the “hopper”

i will have soon the molds to make the electronic control box with recycled plastic, and the it will be possible to sell it on the bazar alike the shredders.

i will add some safety improvements such as a barrel insulation.

thanks for your help,

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#7

That’s a nice idea. Just some remarks about using a stepper (Nema34 with driver & power supply = around 200$) & Arduino (~20$) might be rather hard thing to do since you won’t be able to connect it so easily (it’s all moving), unless you drive the screw directly. I have Nema34 and all sorts of leads crews around and can try it for you …i should check this out anyway …
And yeah, might be more practical to use the hand drill instead as Stan said. I am rather worried that the jack may bend and break over time since the main forces attack it from the side. You use a person weight to checkout at which forces it starts skewing the jack btw. Very like it’s enough to inject most of your objects.
Congrats !

#8

hi PPboys,
thanks for your comments.
yes i looked about arduino and it’s more complex than it looks like after the 1st injection trial.
thing is…it works without so let’s remain simple !

a slight improvement of the feed neck, an inside rod to “pre-push” plastic and the cordless drill might help to get more plastic through the tube.
the stroke of the jack, although it’s only 200mm, requires a lot of revolution before pushing effectively the plastic.
waste of time and the plastic cools down during this time.

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#9

I think at the end of your stroke the scissor jack reduces your effective force compared to the lead screw driving it. An alternate low cost approach would be just to use a long lead screw with a motor at the end. Then the torque stays constant.

#10

Hi Stan. Thanks for your comment.  I thought about the cordless still too.  But an arduino based gives more options. I Will think about both options and let you know the résults.

#11

Interesting design. There are online scissor jack and leadscrew calculators that will get you to a force vs. torque value for a given position. I would be tempted to be lazy and just try a cordless drill or impact driver. It will be interesting if the motion is fast enough to avoid a plug solidifying in a cold mold.
I’m not sure an arduino is needed instead of just a forward/reverse switch. Figuring out how to detect when the mold is full (torque rise) may be useful. You kind of get this for free with the clutch on the cordless.

Good luck, interested in your results.