Injection molding photos

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.

Simple-minded question:-

What does one do for venting in an injection mould?

Mark Rand(currently trying to re-make some rubber parts) RTFM

Mark Rand fired this volley in news: snipped-for-privacy@4ax.com:

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 the cavities.

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.

LLoyd

I'd be really interested in hearing your experiences with this -- my '78 Newport needs quite a few rubber parts replaced, and I've had zero luck finding them.

--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.

Anyone looking for a simple injection molder machine check out

He's one of my customers.

Randy

Thank You, Randy

Remove 333 from email address to reply.

--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.

--Wrote to my pal Duke and he sent me some sketches of how he did his home vulcanizing. If you like I can forward 'em via email, to give you an idea of how he did it.

steamer fired this volley in news:4bd5ca1e$0$1654 $ snipped-for-privacy@news.sonic.net:

Is this a commercial tribo-melt machine, or a "drill press" type home injector?

LLoyd

"How to Cast Small Metal and Rubber Parts" by Cannon is your text. Still available from Amazon, I got mine 20 years ago. I've seen it in several libraries, too. Focus is on car restoration parts.

Stan

That would be interesting...

My current attempts are heading towards gravity casting with 2 part PU based rubber, but I know that its oil resistance is less than perfect.

Mark Rand RTFM

--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: