Home Injection Molding





Introduction: Home Injection Molding

This Instructable explains how to make real injection molded plastic parts using a simple hand-operated machine. I realize most of you reading this don't have one of these machines, but I decided to post here anyway just to let all the garage inventors out there know that such a cool tool even exists.

More details about the machine can also be found at www.injectionmolder.net


Step 1: Machine Set Up

a) Plug in the machine. b) Turn on the power switch. c) Adjust the thermostat to the desired temperature.

Step 2: Insert the Mold

a) Place a mold in the machine. b) Make sure the sprue hole on top of the mold lines up exactly with the injection nozzle. c) Clamp the mold in place by turning the vise handle clockwise.

Inexpensive homemade molds can be made using an epoxy or urethane resin. Or, by machining a desired cavity into an aluminum block using a benchtop CNC machine.

Step 3: Pour in Some Plastic Pellets

Pour some plastic pellets into the injection tube. Wait until they melt (1-2 minutes).

Step 4: Pull Down Handle to Inject Plastic

Pull down on the handle with a quick, but steady motion. You will feel a solid resistance when the mold cavity is full. Hold the handle there for a few seconds, and then lift it back up until it locks place.

The downward force on the handle causes the injection nozzle to press down tightly against the top of the mold, allowing the molten plastic to flow directly into the sprue hole.

The time it takes to pull down the handle will vary, depending on how much plastic you are injecting. A small part (1-2 grams) may only take about 2-3 seconds to inject (plus a few seconds holding time). A larger part (5-10 grams) may take 10-15 seconds or longer to inject (plus a few seconds holding time).

Step 5: Unclamp and Remove the Mold

Wait for the molten plastic to cool in the mold for a short while (usually 5-30 seconds depending on size and shape of part). Then, unclamp the mold and remove it from the machine. Then, separate the two mold halves from each other.

Step 6: Remove the Part From the Mold

a) Remove the part from the mold. b) Cut off the sprue, and trim away any excess plastic (i.e. flash) there may be around the edges of your part.

That's it, you're done!!

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    How does the air escape from the mold while injecting the molten plastic?

    Guy on YouTube shows how to make one and how to sort recycle plastics.

    This is really interesting stuff, but where do you get or how do you make the metal molds that would be used with something like this?

    Can you tell me about the owl mold?

    can i use this to make my own bey parts?

    Nice machine and simple!!! What material is used for the molds?

    Cast iron was the original material many years ago. Common molds of today are steel or aluminum (depending on use, the steel molds will make many copies before degrading compared to aluminum) many at-home injection molders will use an epoxy cast.

    Nice machine, would have been better if you gave some info or links to who makes or sells them. Wonder if you could use recycled plastic, just need to shred it up. I work in a plastic factory for 5 years, the machines are huge. I've been making pewter figurines for years, have dozens of molds, pretty sure the melt temp is about the same as PET (470 degrees F).

    Now, I've done neither pewter work nor plastic molding, but if you have, the main difference is loading the hopper, and using pressure to get material into the mold. I suspect HarveyH44 you'd obtain excellent results in short order.