Reaction Injection Molding (RIM) and Vacuum Casting have the same molding material of liquid polyurethane (PU), are two different techniques that are used for low volume manufacturing plastic parts, both RIM and Vacuum Casting have the benefits of competitive price and fast delivery since their cheap and fast tooling fabrication cost and time, are playing increasingly important role in rapid manufacturing area. However, they also works different from each other, Hereinafter it is the brief introduction of their differences:
1. Different tooling materials. Vacuum Casting tooling material is the soft pure silicone rubber, our RIM tooling materials are usually silicone rubber and hard epoxy resin (in few cases, ABS or Aluminum), thus RIM tooling is more durable than Vacuum Casting tooling to deliver more injection molding shots.
2. Different molding material options. Vacuum Casting materials have the options with properties of similar ABS, similar PC, similar PMMA, similar PP and other similar engineering plastic materials. RIM material has only one option PU with property of high strength and better shrinkage control than Vacuum Casting materials.
3. Different molding environment. Vacuum Casting works in vacuum environment, air bubbles will exist in the vacuum cast parts if not complete vacuum working environment since its zero injection molding pressure. RIM works in the nature air pressure without limitation of definite air pressure environment.
4. Different solidification time. To shorten the solidification time for vacuum cast parts, the parts will be heated in oven for several hours. RIM parts solidify in nature temperature with much shorter solidification time. Generally, for one same part, if Vacuum Casting takes 3-4 hours to completely solidify, RIM takes just 1 hour.
5. Different molding size. Vacuum Casting is usually suitable for manufacturing the small-sized parts for relatively much cheaper and faster tooling fabrication. RIM is suitable for manufacturing the big-sized parts for relatively more durable tooling and faster solidification time, such as automotive bumpers, big housings, large covers, etc.
6. Different tooling life. To keep the molding tolerance, the Vacuum Casting tooling will be scraped after usually 10-20 shots, or the preservation time over one month. By replacing the silicone rubber pieces of the RIM tooling after usually every 100 shots, the RIM tooling can reach up to 1000 shots with preservation time usually two years.
We are respected in Reaction Injection Molding industry in China, the RIM service we send out to global market are quick, economical and quality that are proven by the customers used our service, especially from automobile field. We look forward to doing more and better by our continuously improving RIM expertise and experience.