Silicone Injector Gives Parts Production A Shot In The Arm

Many of us are happy to spend hours cooking up a solution that saves us seconds, if success means never having to do a hated task again. [frankensteinhadason] molds enough silicone parts that he grew tired of all the manual labor involved, so he built a silicone injector to do it for him. Now, all he has to do is push the handle in notch by notch, until silicone starts oozing from the vent holes in the mold.

The mold pictured above is designed to make little shrouds for helicopter communications connections like this one. His friends in the industry like them so much that he decided to sell them, and needed to scale up production as a result. Now he can make six at once.

He designed brackets to hold a pair of syringes side by side against a backplane. There’s a lever that pushes both plungers simultaneously, and adapters that keep the tubing secured to the syringe nozzles. Ejected two-part silicone travels down to a double-barrel mixing nozzle, which extrudes silicone into the top of the mold.

Naturally, we were going to suggest automating the lever operation, but [frankensteinhadason] is already scheming to do that with steppers and an Arduino. Right now he’s working on increasing the hose diameter for faster flow, which will mean changes to the adapter. Once that is sorted, he plans to post the STLs and a video of it pumping silicone.

Ever thought about doing the reverse, and using silicone to mold hot plastic? Yeah, that’s a thing.

Via r/functionalprint

14 thoughts on “Silicone Injector Gives Parts Production A Shot In The Arm

    1. US English idiom meaning a stimulus — I always equated this to something like adrenaline or morphine which would let someone keep fighting a battle through fatigue or pain.

      The author uses the title as an observation that this particular task was once dreaded and is now made easy by the invention. It is also a play on words because the main portion of the invented device is made of syringes, which could be used to give a literal injection or shot in the arm.

    1. Buy a standard or motorized caulk gun like any of the ones listed on your link and use it to fill molds with precisely measured and mixed 2-part silicone. After you’ve tried to do that you might want to revise your comment.

    2. While there’s a few manual 2 part dispensers there, none would provide a smooth injection of the entire tube for the entire push as you’d normally want in an injection molding setup like this.

      You’d have to be closer to this.

      https://www.grainger.com/product/3EAE1?gclid=Cj0KCQjww7HsBRDkARIsAARsIT5H1t6JZjmgqwjdzFjeHekkq0l952zFKtTak5uQdr_ztVHccOXi3TcaAtdaEALw_wcB&cm_mmc=PPC:+Google+PLA&ef_id=Cj0KCQjww7HsBRDkARIsAARsIT5H1t6JZjmgqwjdzFjeHekkq0l952zFKtTak5uQdr_ztVHccOXi3TcaAtdaEALw_wcB:G:s&s_kwcid=AL!2966!3!264955915661!!!g!461781425234!

      and eventually this with his servo setup.

      https://www.nordson.com/en/divisions/sealant-equipment/products/meters-and-metering-systems/105-series-2-part-shot-meter

  1. Any idea: How to curing standard (non 2parts) and cheap silicone for caulking gun molded in for without air access?
    I am trying mold
    I am trying inject silicone into 3d printed form its fishing bait but there is problem with curing and open separate the result.
    i need speed up curing process . normal open air silicone is set after 24h and its easy to remove from form when is there humidity from air.
    but i will not set when is closed in 2 parts form :(
    special silicones for molding are here extra expensive starting 50EUR and more and they have limited time for 12-24months.
    my idea was using some fluid substance for fast curing in closed forms.

  2. If the goal is to make large quantities of this, I’d looking into finding a company that has a small LSR injection moulding system (something like a Babyplast 6/12 LSR will do for for a product like this. Or look into buying one yourself outright). I doubt you’d ever be able to make these economically with a jury rigged system with small syringes.

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