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How to deal with the foaming and peeling on the surface of aluminium profile?
Bubble or peeling: Bubbles with convex shape appear on the surface of the product, which are common in the head and tail. The complete bubbles are called bubbles, and the cracked ones are called peeling.
1. Causes of bubble and peeling in extruded products
1. The abrasion of the extrusion cylinder and the extrusion pad is excessive, the dimension of the extrusion cylinder and the extrusion pad is not matched properly, and the diameter difference of the gasket used exceeds the allowable value.
2. Extrusion cylinder and cushion are too dirty, sticky with oil, moisture, graphite, etc.
3. Lubricating oil contains water;
4. The ingot surface has too many troughs, too deep, or there are air holes and sand holes on the ingot surface, loose structure, oil stain and so on.
5. When the alloy is replaced, the cylinder is not cleaned up.
6. Extrusion cylinder temperature and extrusion ingot temperature are too high.
7. The temperature and size of ingot exceed the allowable negative deviation.
8. The ingot is too long, fills too fast, the ingot temperature is uneven, which causes non-drum filling, so the exhaust in the barrel is incomplete, or the operation is inappropriate, and the exhaust process is not carried out.
9. The die hole design is unreasonable or the cutting residue is improper. The residue in the shunt hole and the diversion hole is partially taken out, and the gas in the space enters the surface during extrusion.
II. Elimination methods
1. Reasonably design the matching size of extrusion cylinder and gasket, check the tool size regularly to ensure that it meets the requirements, and repair the big belly of extrusion cylinder in time, so that the gasket can not exceed the tolerance.
2. Keep the surface of tools and ingots clean, smooth and dry.
3. When replacing the alloy, the cylinder should be cleaned thoroughly.
4. Check equipment and instruments frequently to prevent excessive temperature and speed.
5. Strict implementation of process regulations and systems;
6. Reasonable design and manufacture of tools and dies, diversion holes and diversion holes are designed into 1-3 degrees of inclination;
7. Strict operation, correct cutting of residue and complete exhaust.