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Precious Plastic Oslo (WIP)

This topic contains 7 replies, has 3 voices, and was last updated by  Stan 1 year ago.

4
Martin Gautron martingautron

Precious Plastic Oslo (WIP)

19/09/2019 at 13:57

Finally sharing some of our machines and tests. I made a first injection machine based on PP design and tested it with different molds made out of steel and aluminium. Even got to test it with a fairly complex 3 parts mold for a flute made by @siemenc. I am now making a more compact-bench injection machine to focus on CNC’d molds for small items.

The first things I’m trying to improve from my first machine are :
– tolerance between piston and barrel, my last one was very loose since i couldn’t find a seamless tube matching the piping system dimensions in Norway.
– Nozzle-Mold connection, I’m trying a clamping system instead of a screwing one, time and volume consuming. I will try a “nipple nozzle nut” tip that should fit in the chamfered hole of the mold once clamped in position.
– The pressure provider, still working with the lever but I want to change for a more linear system, ideally a rack and pinion system like on a press drill.
– Insulation of the barrel nozzle, I had some weird results when working in windy locations, maybe losing some precious degrees too fast…

I also found some inspiration from “The secrets of building a plastic injection machine” book by V. Gingery to build the bench version.
The new barrel I made is from a solid aluminium rod, lathed down to fit the heating elements, ended up much thicker than the original tube, so now the body should absorb and store more heat. I also decided to use only one temperature controller and 3 heating elements, since the nozzle is not so big I felt i didn’t need it…
I’m curious about the consequences. The machine is almost ready for testing as I write…

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starter
19/09/2019 at 14:04
1

My 1st CNC’d aluminium mold (Imac stands makes very milling-friendly Alloy), very satisfying test got me to improve the machine before pushing further…

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starter
19/09/2019 at 14:12
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The flute mold made by @siemenc, and some results… I was surprised to see how much “force” goes inside the mold, the aluminium blocks tends to spread in the middle despite the thickness.
View of the 3D mold, courtesy @siemenc

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starter
19/09/2019 at 14:34
2

Waiting to assemble the shredder I’m using plastic flakes from the Bazar and occasionally some don’t-try-this-at-home electric planer in a box to shred objects.
I’ve been mostly pressing PP so far and it shrunk a lot on thick parts.
Simple molds made from geometric parts, works fine for simple shapes…
One 3D mold also made by siemen to do the firsts tests on the flute

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starter
19/09/2019 at 14:41
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A few examples…

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starter
19/09/2019 at 14:49
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A few shots of the new machine in the making

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dedicated
19/09/2019 at 18:16
1

Awesome you’re sharing your process @martingautron ! Need to pass by you guys soon again, once things have cooled down a bit here. Curious for the new progress you’re making.

warrior
19/09/2019 at 18:45
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Those are great results.
I used an arbor press to provide the injection force in my DIY configuration. It works very well. https://davehakkens.nl/community/forums/topic/portable-desktop-injection-machine/page/3/
Thanks for posting, looking forward to how your improvements work out.

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