I'd like a simple plastic injection machine or designs

Hi Jeff, it's been about 25 years so I can't remember any company names. One was a "Hot Runner" specialist and they where running multi cavity thin walled margarine containers cycling at about 5 seconds. I managed a toolmaking company for over 20 years, mainly intricate stuff (2 shot/3Shot) stuff no one else wanted to do. We also did mobile phone moulds but as you say the cheap Chinese stuff killed the trade.

Chris

Hi Chris, one big name in the thinwall packaging container business was Stackteck, they are still in business, along with a lot of other package / container and closure moulders. Husky and Mould Masters were the big guns in hot runner systems for many years. Still operating but I think smaller scale these days.

I have also done some work with multishot moulding, especially for TPE or TPV overmoulding. Had several large structural / cosmetic mouldings projects with gas assist and also coinjection two polymer moulds (nightmares). One interesting project was a family of moulds for two shot rigid plastic keycaps for industrial keyboards. The letters were moulded first in cav 1, usually in white or yellow, the shot lifted up and set back into cav 2 with a helical cam, then the cap shot around the light coloured letters. The second shots were all colours. Sealoffs at the colour boundaries was required to be zero flash. OK once we had it dialed in. The idea was that the letters and numbers could never wear away, in critical reliability systems ie powerplants and military stuff. That was OK, keycaps lasted forever, but people still pushed the wrong buttons once in a while!

Jeff, I am sure it was Husky that I went to see. Keyboard keycaps, we made around 30 16 impression mould tools for IBM keyboards. That's 30 for the main button and 30 for the printable cap. CNC spark macines came in for the multi cavity stuff. Long retired and out of the game now.