Hydraulic injection molding machines remain a popular option on many shop floors, especially for the production of larger parts.
Once the dominant machine in the injection molding segment, hydraulic machines may be the best option, depending on a shop’s specific needs, electricity costs, and preferences.
These types of machines employ hydraulic cylinders to clamp together two halves of a mold at high pressure. Plastic substrate pellets are then melted, and the liquid is injected into the mold cavity. Once the plastic has cooled and hardened, the mold halves are separated, the part is extracted, and the process is repeated.
On today’s shop floor, hydraulic machines can control clamp forces exceeding 8,000 tons and can produce parts weighing more than 50 pounds. Hydraulic machines are popular for the automotive end market, which requires the production of large, heavy parts such as bumpers.
Hydraulic machines are preferred for actuating core pulls, ejectors, and valve gates as well as thick-walled parts that require longer hold times.
Some of the benefits of a hydraulic press include greater clamp force for larger parts, improved injection rates, high resistance to wear and tear, larger shot size, better injection capability, lower initial purchase price, easier to control for high-level projects.
Hydraulic machines are powerful and use more energy. They also require more maintenance, including changing hydraulic oils and fluids. While they are noisier, as clamp forces increase and control systems improve, hydraulic machines’ precision performance also improves.