Outline of Goals

A project log for Micro Injection Molding Machine

Building a tabletop injection molding machine.

jupdykejupdyke 02/03/2016 at 03:470 Comments

This project is quite daunting and could easily take years to accomplish. Building a small injection molding machine is by no means a simple task and I don't want anyone to think I am fooling myself into thinking it is. I have spent about a year learning about injection molding and doing some simple projects. If you have not checked out my Modular Continuous Track System please do. It documents my experiments with silicone molds and 2 part resin injection.

So this is not my first project and I am quite lucky to have both some funding behind this project as well as access to quite a bit of tools. I would attempt this unless I did have these resources. I have built 2 cnc machines, and a few 3d printers. I don't think this prepares me for this project, but it helps a little.

With a project of this size it makes sense to create smaller milestones. I am currently doing quite a bit of molding using a two part resin and aluminum molds. But I am injecting it by hand and opening the molds by hand. So creating some smaller goals will allow me to use this project earlier. So below is my starting point for an outline.

Stage 1 - Simple Mold Opening / Closing

This version will not be much more than a frame that can open and close the aluminum mold which I am already using.

Stage 2 - Automated Resin Molding Machine

This version will add in the use of a static mixer and resin dispensing. The idea is that the resin I am using has a pot life of 30 minutes, and by heating the mold it might be possible to remove parts from the mold before the resin cures in the static mixer. If this is the case, the parts could be removed and the mold injected again using the same static mixer. This would allow for a semi-automated injection mold.

2 part resin is quite a bit easier to work with than traditional plastic pellets. It just requires mixing and injecting. The main issue with 2 part resins is that they are slow to cure.

Stage 3 - Full Injection Molding Machine

This would be the fully finished machine. The main part of this stage is going to figure out how to design and build the pellet hopper, screw drive, heater and ram. Since this will require higher pressure injection, the closing mechanism will also have to be stronger. So I might increase to a larger pneumatic cylinder, or possibly go to hydraulic. It will also probably require the addition of cooling lines to remove the heat from the mold.