Plastic Processing and Forming – Extruding and Molding
Used in industries that range from consumer products to medical devices, the demand for plastic components is continually growing. Plastic processing is required to convert raw materials into finished products. After forming, additional processes may be required for product completion. In an effort to keep up with demand, plastic manufacturers are seeking ways to improve output and productivity from plastic extruder machines and extruder gearboxes without sacrificing quality. To accomplish this, the correct bearings must be used.
What Are the Common Bearings Used in the Plastics Processing Industry?The plastics industry is dominated by two major categories that require extruders and molding machines. An extruder passes processed plastic through a nozzle into a processed die. The extruder’s gearbox is subject to high torques and high radial and axial loads. Injection molding machines produce parts in large quantities, which require the screw feed and the linear bearings to be insensitive to heat and vibration and have high basic static and dynamic load ratings. Common bearings that are used in plastic processing for the extrusion or molding industry include:
- Rod Ends
- Cam Followers
- Mounted Units
- Roller Bearings
- Thrust Ball Bearings
- Ball Screws: Used in mechanical drive parts such as the injection cylinder, mold clamping cylinder, ejector shaft, and plasticization unit, ball screws withstand high load drives in harsh environments.
- Thrust Ball Bearings: Used to support thrust and radial loads within extrusion shafts, thrust ball bearings resist shock loads and accommodate misalignment.
- Linear Bearings: Used to carry a load on a rail, linear bearings must work at high speeds without overheating.
What Are Some Common Applications for These Bearing Types?Electrically driven extrusion molding machines increase accuracy, are cleaner, and use less energy. They also put bearings in a much harsher environment. Some of the conditions that force bearings to work harder include low lubrication, poor melting conditions, and low heat generation. Bearings used within the plastic processing and forming industry must be able to withstand heavy loads and resist dynamic peak loads, high rigidity, and high heat. Common applications of these bearing types can be found in these extrusion machine parts:
- Injection Cylinder
- Mold Clamping Cylinder
- Ejector Shaft
- Press Cylinder
- Extrusion Gearbox