If you’ve ever wondered how large, hollow plastic structures like tanks and drums are made, you’re in luck: [Andy] Not only does it fill us with the details of rotary casting and molding, he also created this sweet little rotary casting machine to help with his DIY projects.
Granted, [Andy]Its build, like a car’s fuel tank or kayak, won’t make anything too big. Not only is it larger for smaller parts, but these structures are usually made with a process related to rotating molding. Both processes use a bound multipart mold that is partially filled with plastic resin and then rotate the mold around two axes to distribute a thin layer of resin around the inside of the mold. The difference is that roto-molding uses a thermoplastic resin, whereas roto-casting uses resins like polyurethane and silicone set at room temperature.
The machine is easy to see, but only because he has worked hard to optimize it. The videos below cover the build in detail – if you really want to see it, skip the 11:38 mark in the second video. Although you will miss some juicy tidbit, such as a perfect 90 ° joint casting in square tubing. There are also custom tools [Andy] He used to run the spinning of the mold to split the bead chain, which was pure talent.
Machine and using a complex nine-piece mold, [Andy] RC from polyurethane resin was able to make significantly more detailed tires for cars. We want to see what this rig is good for – almost as much as we want to see the details of how the mold was made. We’ve seen other rotary molding machines before, but it takes the cake to fit and finish.