Awesome. I just finished machining my first prototype injection mold for
rubber baits the other day. Now I need to make an injector ... or wait for
the one I ordered to arrive. LOL.
Thanks for posting that.
Mark Rand fired this volley in
Mark, at the pressures 'real' injection moulding equipment works, the
tenth-of-a-thou clearances between clams is all the venting necessary.
Modern tribo-melt equipment squishes the resin in there at 10,000-20,000
psi. The air is going to move unless you have an hermetic seal. It
takes a different time to squeeze out the air for every
mould/resin/tempedrature combination, but injector ram dwells are set for
the mould AND the resin AND the temperature, and if the mould is well
built, the over-pressure limits kick as soon as the mould is really full
to the flash lines. For really complex forms, the "hot runner" idea is
used, which heats the 'conductor lines'(runners) between the nose of the
injector and the cavities, so the stuff doesn't congeal until it reaches
I don't discourage anyone from trying stuff, but those parts Ed made were
- um - _really_ bad... really... He'd have been a LOT better off trying
to CAST the parts from a low-vis liquid resin.
--Re: making rubber parts: a pal of mine by the name of Duke Croft
made a vulcanizer from an old hot plate, topped with a press that was made
from a brake drum of some kind. He used a garden hose to run the press. Will
see if I can get him to send me some photos.
--Part of what you were seeing were plastic parts made while I was
purging the machine of black Nylatron, replacing it with 'natural' color
Nylon. They look a whole lot better now and the flash is gone too.. Will
crank out more parts once I'm done restoring machine #2.
--I'd put it somewhere in the middle. It's probably the absolute
minimum setup one might consider for limited production. I'm doing prototype
stuff for 'proof-of-concept' so I'm forever tinkering with the dies and I'm
in no particular hurry.
--I would definitely NOT want to do production with this beastie as the
throughput is probably around 10 parts/hr at full gallop, due to very small
size of melt volume, purely hands-on separation of mold halves and parts
from same, etc.
--Update: put up some more photos, this time showing details on the
Honajector. And thanks to the nice folks at the Yahoo injection molding
group I've found a source for the "clamp on thermostat" control for half
the price of the one Simplomatic wanted to sell me. Here's the link: