In the 1960¹s Colin Chapman (1928-1982) the former head of Lotus Cars UK, proposed to his team that they should use “That big press in the sky!” to hold their closed molds together during injection. He was, of course, referring to atmospheric pressure. Thus was formed their early process of Vacuum Assisted Resin Injection (VARI).
Lightweight matched molds were formed with vacuum and resin seals. A glass mat was laid into the cavity and a low-pressure resin mix was fed in centrally, while the mold set remained under vacuum. The VARI system continued into the late 1980¹s and was also notably used in the manufacture of the DeLorean car produced in Northern Ireland. Although still used today by Lotus for limited applications, their own RTM process application has become more prominent.
(used without permission from JHM Technologies website)
John, Just curious…DeLorean bodies were made from stainless steel. Did they use vacuum molding to shape the panels? I thought (maybe erroneously) that a vacuum press was only used on materials that “set up” like epoxy, glue, etc. Doug
There are all kinds of metal forming methods. Stretch forming is an interesting one. Explosive fabrication is another. It’s all a balance of material properties and desired shapes and finance. The term “crossover applications” only has meaning if people look to other pastures. Guys like Morey, Pope, and Simmons were exposed to other worlds, as were the sailboard people, a diversity perhaps seldom seen in this day where there is enough money inside surfing to make running into walls not only profitable but downright glamourous.
I don’t know a thing about DeLorean cars other than they had stainless steel bodies. Your question sparked my interest though and a quick search shows that they did use the VARI resin injection molding system in the construction. If you check the link, and scroll down the opened website you will see a pic of the molding in process. Can’t tell what the part is though. Maybe part of the body substructure? The stainless body panels must have been formed differently.