EXTRUSION

EXTRUSION

Extrusion is a process used to create objects of a fixed cross-sectional profile. A material is pushed or drawn through a die of the desired cross-section. The two main advantages of this process over other manufacturing processes are its ability to create very complex cross-sections and to work materials that are brittle, because the material only encounters compressive and shear stresses. It also forms finished parts with an excellent surface finish.

Extrusion may be continuous (theoretically producing indefinitely long material) or semi-continuous (producing many pieces). The extrusion process can be done with the material hot or cold.

The most commonly extruded materials in our application spectrum include metals and polymers.

Extrusion is a process used to create objects of a fixed cross-sectional profile. A material is pushed or drawn through a die of the desired cross-section. The two main advantages of this process over other manufacturing processes are its ability to create very complex cross-sections and to work materials that are brittle, because the material only encounters compressive and shear stresses. It also forms finished parts with an excellent surface finish
Hot extrusion is a hot working process, which means it is done above the material’s recrystallization temperature to keep the material from work hardening and to make it easier to push the material through the die. Most hot extrusions are done on horizontal hydraulic presses that range from 230 to 11,000 metric tons (250 to 12,130 short tons). Pressures range from 30 to 700 MPa (4,400 to 101,500 psi); therefore lubrication is required. Lubrication can be oil or graphite for lower temperature extrusions; or glass powder for higher temperature extrusions. The largest disadvantage of this process is its cost for machinery and its upkeep.
Cold extrusion is done at room temperature or near room temperature. The advantages of this over hot extrusion are the lack of oxidation, higher strength due to cold working, closer tolerances, good surface finish and fast extrusion speeds if the material is subject to hot shortness. Materials that are commonly cold extruded include: lead, tin, aluminum, copper, zirconium, titanium, molybdenum, beryllium, vanadium, niobium and steel.
Warm extrusion is done above room temperature, but below the recrystallization temperature of the material. The temperatures range from 800 to 1800 °F (424 to 975 °C). Warm extrusion is usually used to achieve the proper balance of required forces, ductility and final extrusion properties.