New Injection Molding Press

The Rubber Group Adds Injection Molding Press for Larger Parts

Rob PruynMolding Services

The Rubber Group is using a new DESMA 968.400 ZO Benchmark (S2) rubber injection molding machine to produce larger parts such as insulators for power transformers. The rubber molder ordered the vertical injection molding press in the fall of 2019 and is already using it to produce large electrical insulators that separate conductors and prevent the passage of current. DESMA, the manufacturer of the press, is a leader provider of injection molding equipment for technical rubber and silicone molded articles. The Rubber Group’s new machine has a 6.6 liter shot, 31.9 in. x 38.6 in. platen, and 505 tons of clamping force. 

Clamping and Injection

The clamp end of an injection molding press provides force to counter the pressure that’s applied from the injection unit. The tonnage that’s applied, the location of the clamping force, the type of clamping mechanism, and the size of the mold base affect the success of the molding process. The Rubber Group’s new DESMA 968.400 ZO Benchmark (S2) rubber injection molding press features a powerful clamping unit with a mold opening stroke of 32 in., a minimum mold height of 7 in., and maximum daylight of 39 in. The vertical stroking unit has a fully hydraulic clamping system and a high-speed horizontal sliding mechanism. 

To produce large molded parts, a rubber injection molding press needs to have a shot size with a large volume – the amount of rubber injected into the mold.  Moreover, the machine’s injection unit needs to have a high enough pressure and flow rate to support proper part filling. The first-in first-out (FIFO) injection unit on The Rubber Group’s new press has an injection volume of 42.8 in.3 and is horizontally arranged for injection through a fixed platen. The maximum shot is 17.4 lbs.

Controls and Automated Data Collection

The Rubber Group’s new injection molding press is equipped with a DESMA DRC 2020HT control system that balances the automated control of process variables with oversight by skilled operators. The control system features a fully-programmable multiphase injection profile and a fully-programmable multiphase plasticizing (refilling) profile, both of which have closed-loop speed and pressure controls. There’s also an operator touchscreen and up to four mold safety pressures, each of which is freely selectable and adjustable for the opening and closing movements of the core lifters and the mold carrier.

Importantly, The Rubber Group’s new DESMA 968.400 ZO Benchmark (S2) rubber injection molding press stores important process and production data that can be accessed in real-time and stored indefinitely. This advanced technology allows upper and lower limits on parameters such as temperatures, injection times, injection pressure, and turn time. If the injection molding press is outside of these limits, the operator is notified and can make the necessary adjustments.   

Contact The Rubber Group to learn more about rubber injection molding for larger parts.