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　　Selection of Materials

　　The materials commonly used in sheet metal processing are cold-rolled sheet (SPCC), hot-rolled sheet (SHCC), galvanized sheet (SECC, SGCC), copper (CU), copper, beryllium copper, aluminium sheet (6061, 5052, 1010, 1060, 6063, hard aluminium, etc.), stainless steel (mirror, wire drawing surface, fog surface), according to the different functions of products, different materials are selected, and the products are usually used from them. Consider the way and cost.

　　1. Cold rolled sheet SPCC is mainly used for electroplating and paint-baking. It has low cost and is easy to form. The material thickness is less than 3.2mm.

　　2. Hot-rolled SHCC, material T (> 3.0mm), is also electroplated, paint-baking parts, low cost, but difficult to form, mainly flat parts.

　　3. Galvanized sheet SECC, SGCC. SECC electrolytic plate is divided into N material and P material. N material is mainly not used for surface treatment, which has high cost. P material is used for spraying parts.

　　4. Copper; mainly used for conductive materials, its surface treatment is nickel plating, chromium plating, or no treatment, high cost.

　　5. Aluminum plate; commonly used surface chromate (J11-A), oxidation (conductive oxidation, chemical oxidation), high cost, silver plating, nickel plating.

　　6. Aluminum profiles; materials with complex cross-section structure, which are widely used in various kinds of cartons. The surface treatment is the same as that of aluminium plate.

　　7. Stainless steel; mainly used for no surface treatment, high cost.

　　Map audit

　　To compile the technological process of parts, first of all, we need to know all kinds of technical requirements of part drawings; then the drawing surface audit is the most important part of the process planning of parts.

　　1. Check if the drawing is complete.

　　2. Graphic view relationship, whether the labeling is clear and complete, labeling size units.

　　3. Assembly relationship and key dimensions are required for assembly.

　　4. The difference between old and new layout.

　　5. Translation of foreign pictures.

　　6. Code conversion at table.

　　7. Graphic problem feedback and burying.

　　8. materials.

　　9. Quality requirements and process requirements.

　　10. A quality control stamp shall be affixed to the official drawing.