What are bubbles or peeling: Convex bubbles appear on the surface of the product, usually at the head and tail. The complete ones are called bubbles, and the ruptured ones are called peeling.
1. The causes of bubbles and peeling caused by aluminum plate extrusion
1. The wear of the extrusion cylinder and the extrusion pad is out of tolerance, the dimensions of the extrusion cylinder and the extrusion pad are improperly matched, and the diameter difference of the gasket used exceeds the allowable value;
2. Extrusion barrel and extrusion pad are too dirty, sticky with oil, water, graphite, etc.;
3. Lubricating oil contains water;
4. There are too many shovels on the surface of the ingot, too deep, or the surface of the ingot has pores, sand holes, loose tissue, oil stains, 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 temperature and size of the ingot exceed the allowable negative deviation;
8. The ingot is too long, the filling is too fast, and 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 exhaust process is not performed;
9. The design of the die hole is unreasonable, or the residual material is not cut properly, the residual material in the diversion hole and the diversion hole is partially carried out, and the gas in the gap enters the surface during extrusion.
2. How to eliminate air bubbles and peeling caused by aluminum plate extrusion
1. Reasonably design the matching size of the extrusion cylinder and the extrusion gasket, and check the tool size frequently to ensure that it meets the requirements. The extrusion cylinder should be repaired in time if there is a belly in the extrusion cylinder, and the extrusion gasket should not be out of tolerance;
2. Keep tools and ingot surfaces clean, smooth and dry;
3. When replacing the alloy, clean the cylinder thoroughly;
4. Check the equipment and instruments frequently to prevent the temperature from being too high and the speed too fast;
5. Strictly implement the process regulations and various systems;
6. Reasonably design and manufacture tools and molds, diversion holes and diversion holes are designed to have an internal slope of 1°-3°;
Strict operation, correct cutting of residual material and complete exhaust, avoiding these problems in daily production, can reduce loss and increase yield.