Injection Molding Machine
A two-platen injection molding machine removes the rear platen and toggle linkage of the classic three-platen toggle design and generates the clamping force with a locking mechanism connected directly to the tie bars. At the same tonnage the machine length becomes markedly shorter, and the mold opening stroke and mold height range become larger. It is common on large machines of 600 tons and above.
At large tonnages the toggle design becomes a solution that is both long and heavy on maintenance. The two-platen design moves the moving platen with hydraulic cylinders; when the mold closes the tie bars are locked, and short-stroke high-pressure cylinders apply the clamping force.
The gain is floor space and flexibility with large molds: a larger tonnage fits on the same floor, and deep, thick molds run comfortably. Below 600 tons this advantage often does not cover the cost.
When large parts (automotive bumpers, containers, household appliance housings), limited factory space and high mold weight come together. At small tonnages the toggle design is more economical.