Causes of formation of shrinkage in aluminum extrusion process and preventive measures

[China Aluminum Network] tailing is a unique waste product in the extrusion process of aluminum alloy profiles. It is divided into a hollow shrinkage tail and a ring shrinkage tail. The hollow shrinkage tail is due to oil and squeezing residue on the extruded gasket. Too little material is left, resulting in a serious shortage of metal supply and other reasons to form a hollow funnel tail; ring shrinkage is mainly due to the end of the aluminum extrusion process, the metal supply in the deformation area is insufficient, forcing the metal along the extrusion gasket around Lateral turbulence occurs, and the cold and oily metal on the edges and side surfaces is circulated back into the product. The ring-shaped shrinkage is generally on the cross-section of the end of the product. It is mostly a continuous or discontinuous ring shape. . The main measures to prevent shrinking: 1) Reduce the temperature difference between the aluminum ingot and the tool, or use low temperature extrusion. 2) Ensure that the surface of the ingot is clean and evenly heated. 3) Do not grease the squeegee or wipe the pad with an oil rag. 4) Improve the surface smoothness of the mold and the extrusion tube, and clean the extrusion tube in time. 5) Reduce the extrusion speed at the end of the extrusion process. 6) Use lubrication and reverse extrusion. 7) Leave residual material and cut tails as required, or increase residual thickness appropriately