How to deal with blistering and peeling of extruded aluminum profiles?
Bubbles or peeling: There are convex bubbles on the surface of the product, which are common in the head and tail, and the complete bubble is called the rupture.
First, the reasons for the extrusion of product bubbles and peeling
1. Excessive wear of the extrusion tube and the pressing pad, improper matching of the size of the extrusion tube and the pressing pad, and the difference in the diameter of the used gasket exceeds the allowable value;
2. The extrusion cylinder and the extrusion pad are too dirty, and are stuck with oil, moisture, graphite, etc.;
3. The lubricating oil contains water;
4. There are too many shovel grooves on the surface of the ingot, too deep, or there are pores, blisters on the surface of the ingot, loose tissue, oily, etc.;
5. When the alloy is replaced, the inside of the cylinder is not cleaned;
6. Extrusion barrel temperature and extrusion ingot temperature are too high;
7. The ingot temperature and size exceed the allowable negative deviation;
8. The ingot is too long, the filling is too fast, the temperature of the ingot is uneven, causing non-drum filling, so the exhaust in the cylinder is not complete, or the operation is improper, and the exhausting process is not performed;
9. The die hole design is unreasonable, or the residual material is improperly cut, and the residual material in the split hole and the flow guiding hole is partially taken out, and the gas in the gap enters the surface when pressed.
Second, the elimination method
1. Reasonably design the matching size of the extrusion tube and the extrusion gasket, and regularly check the size of the tool to ensure that it meets the requirements. The large tube of the extrusion tube should be repaired in time, and the pressing pad should not be out of tolerance;
2. The surface of the tool and ingot remains clean, smooth and dry;
3. When replacing the alloy, thoroughly clean the cylinder;
4. Always check equipment and equipment to prevent excessive temperature and excessive speed;
5. Strictly implement the process rules and systems;
6. Reasonably design and manufacture the mold, the diversion hole and the diversion hole are designed to have an inclination of 1°-3°;
7. Strict operation, correct cutting of residual material and complete exhaust.