Precious Plastic Oslo (WIP)
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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…
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…
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
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.
Those are great results.
I used an arbor press to provide the injection force in my DIY configuration. It works very well. http://onearmy.world/community/forums/topic/portable-desktop-injection-machine/page/3/
Thanks for posting, looking forward to how your improvements work out.
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