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I apologize for reviving an old thread, but i stumbled across this site and I too am building a pouring machine. Has anyone made any progress with the machines mentioned in this thread?
I've got two machines planned, a CNC (or PLC) driven machine to pour open molds and a PLC driven pneumatic injection machine for 2piece molds. So far I've collected some of the parts as I find them on eBay but am not convinced what way to go. I have put the injection machine on high priority over the pouring as it will be a less complicated machine.
Currently my main roadblock is figuring out how to transfer the plastic into the ram chamber. I have toyed with a few ideas, but haven't tried anything yet. Cost is a main factor in building this machine so I'm looking for solutions that are "eBay" friendly. My first idea was to use a peristaltic pump to pump the plastic. These can be found pretty cheap on eBay ($40 or so). The problem is most of them are stepper motor driven and the controllers for those are not cheap. I also don't know how they will withstand the heat.
I then thought of using an "auger" to push the plastic out of the chamber and into the injection ram (like big commercial injection machines). This may be a solution as I could probably put this together with a few pipe fittings and a drill bit. Then timing is an issue that can be overcome.
Another thought was to have a constant pressure type system mentioned earlier in this thread. This is how machines like the Nordson hot melt systems work. I really liked the idea redg8r has with the paint containers. Did you ever get this working? Any pics?
Last but not least would be vacuum. I could have a electric control valve that connected to the ram chamber that would open as the ram withdrew causing the plastic to siphon into the chamber. The valve would then close and the nozzle valve would open as the ram was charged and the piston pushes the plastic out. This may be difficult as the valves would get gunked up with plastic and could fail.
Ok, with all that said what do you guys recommend? Have you completed your machines? Pics? Once I complete this machine I will be working on the pouring machine that will pour up to 3 colors in each cavity to create bloodlines, spots, patterns, etc...
Thanks in advance!
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