Knowledge of shrinkage cavity defects in tail of extruded aluminium alloy.
A. The Reason cause the shrinkage cavity defects in tail of extruded aluminium alloy
1. Extrusion defective material left too short
2. Extrusion gasket spouts with oil or not clean
3. Ingot or wool surface is not clean
4.The length of the cut tail of the product is not in accordance with the regulations
5. Extrusion barrel lining is super-poor
6. The extrusion end suddenly increases the extrusion speed.
B. The elimination method of aluminum extruder formation and measures to reduce and prevent the formation of shrinkage cavity defects:
1. Strictly according to the process provisions cut pressure residual and sawing head, tail, to maintain the squeeze tube lining intact, prohibit the extrusion gasket oil, reduce the pre-squeeze temperature of aluminum rod, the use of special convex gaskets, the use of reasonable length of debris.
2. Extrusion tool, aluminum rod surface should be clean
3. Always check the size of the Extrusion barrel and replace the unqualified tools
4. Smooth extrusion. In the late extrusion should slow down the extrution speed, the thickness of the proper residual pressure, or use the increased residual method of extrusion.