Suggested tweaks for Injection machine

Hi all,
We just managed to make a surf wax comb with the injection machine here in Sri Lanka.
Lee from Colombo Design Studion designed the proudct and the mold. Look him up for more details from that site of the process
Here is what we have learned using the injection machine itself.
It seems there is no need to preheat the mould if the vents are big enough.You will still need some good pressure to force the polymer into the mold so i would make the lever of the plunger 2 feet longer next time. Should add a lot more pressure and make your life easier and it will be easier to use for all sizes and shapes of people.
Also, we found that, as we are working in semi open spaces here, that even little wind messes with the sensors and teh real heat insite the pipe. Meaning it is nearly impossible to replicate teh same result in the same time. We wrapped a few layers of crumbled aluminum foil around the pipe, followed by a few layer of some foamier insulation material. We put the foil first so the heating clamps do not melt the insuation foam straight away. Works great like this and we can make 3 products in 40 minutes. Well, still the occasional short shot but works on a very good rate.
We do not attach the mould while heating the plastic as it would sink into the entrance of the mould and solidify a bit. Definitley harder to press it in directly if not impossible. So we use that plumbing tap you can see on the pic, after 40 mins take it off, let some polymer squeeze out (the last bit never gets soft enough), cut it of with a scissor and than attach the mould so we squezze in polymer with “ideal” liquidity.
That’s it. So our three recommendations. Longer lever, insulation, use a tap and cut off first bit of polymer. Happy making.

Thanks for the tips and tricks. Busy building the injection molder now and I’ve been lucky enough to find a ready-made extendable square tube for the lever… Will post pics when its complete.
Does that valve still have a thread? or something to easily connect a mould?

Hi @timslab, Yes that valve has an inner thread. But We only use it as a block so the polymer does not sink into the mould and blocks the mould whe it solidifies. We take off the valve and attach the mould directly to the pipe’s thread. The less way the polymer needs to travel the better.
Let us know how it goes.

Making the Rice & Carry up-cycled precious-plastic wax comb


Here you can read a bit about the mould we have made by Colombo Design Studio.
You find Lee here in the forum as @leebaz.
Cheers,
Henry