In order to meet the requirements of function and appearance of products, the design of sheet metal should ensure that the stamping process is simple, the stamping die is easy to make, the quality of sheet metal stamping is high and the dimension is stable. Detailed sheet metal design guidelines can be referred to the "Part Structural Design Craftsmanship" and "Product Design Guidelines for Manufacturing and Assembly" published by Machinery Industry Press.

process

When the drawings are ready, different blanking modes are selected according to the development drawings and batch sizes, including laser, CNC punch, cutting board, die and so on. Then corresponding blanking modes are made according to the drawings. CNC punch is influenced by cutting tools. For some special-shaped workpieces and irregular holes, there will be larger burrs on the edge. It is necessary to deburr later, and it has certain influence on the accuracy of workpieces. Laser processing has no tool limitation, flat section, and is suitable for special-shaped workpieces, but it takes longer for small workpieces to process. Placing the worktable beside the numerical control and laser is beneficial for the plate to be placed on the machine for processing, and reduces the workload of lifting the plate.

Some available edges are placed in designated places to provide materials for bending test moulds. After blanking, the edges, burrs and contacts should be repaired (polished). At the tool contacts, the workpieces with bigger burrs should be repaired with a grinder, and the contacts with smaller inner holes should be repaired with a corresponding small file to ensure the appearance of the workpiece. At the same time, the shape of the workpiece should be repaired to ensure the positioning of the workpiece during bending, so that the workpiece during bending can be repaired with a grinder. Relying on the same position on the bending machine to ensure the same size of the same batch of products.

After the blanking is completed, it enters the next process, and different workpieces enter the corresponding process according to the processing requirements. There are bending, riveting, flanging tapping, spot welding, convex hull, segment difference. Sometimes, after bending one or two rounds, the nut or stud should be pressed well. Where there are die convex hull and segment difference, processing should be considered first, so as to avoid interference in other processes before processing, and the required processing can not be completed. When there is a clasp on the upper or lower shell, if the clasp cannot be welded after bending, it should be processed before bending.

When bending, it is necessary to determine the tool and groove used in bending according to the size of the drawing and the thickness of the material. To avoid the deformation caused by the collision between the product and the tool is the key to the selection of the upper die (different types of upper die may be used in the same product). The selection of the lower die depends on the thickness of the plate. The second is to determine the order of bending. The general rule of bending is to start from inside to outside, small to big, special to common. The workpiece with pressing edge first bends the workpiece to 30 40 and then press the workpiece to death with the leveling die.

When pressing riveting, we should consider the height of the stud and choose the same and different dies, and then adjust the pressure of the press to ensure that the surface of the stud and the workpiece is even, so as to avoid the scrap of the workpiece caused by the stud not being pressed firmly or pressing out more than the workpiece surface.

There are argon arc welding, spot welding, carbon dioxide protection welding, manual arc welding, etc. Spot welding should first consider the position of workpiece welding, and in mass production, consider positioning tooling to ensure accurate spot welding position.

In order to solder firmly, the bump on the workpiece to be welded can make the bump contact with the flat plate uniformly before the electrified welding, so as to ensure the consistency of heating at all points, and can also determine the welding position. Similarly, to carry out welding, it is necessary to adjust the pre-pressing time, the holding time, the maintenance time and the rest time to ensure that the workpiece can be soldered firmly. After spot welding, there will be weld scars on the surface of the workpiece, which need to be treated by a flat grinder. Argon arc welding is mainly used when two workpieces are larger, but also when they are joined together, or when the edges and corners of one workpiece are processed, so that the surface of the workpiece can be smooth and smooth. The heat generated during argon arc welding can easily deform the workpiece. After welding, the workpiece should be treated by a grinder and a flat grinder, especially in the aspect of edges and corners.

Workpiece surface treatment after bending, riveting and other processes are completed. Different plate surface treatment methods are different. After cold plate processing, surface electroplating is generally carried out. After electroplating, no spraying treatment is carried out. Phosphating treatment is adopted and spraying treatment is carried out after phosphating treatment. The surface of plating plate is cleaned, degreased and then sprayed. Stainless steel plate (with mirror panel, fog panel, wire drawing board) can be drawn before bending, without spraying, if needed spraying to be wooled; Aluminum plate generally adopts oxidation treatment, according to the different color of spraying to choose different oxidation background.

Commonly used are black and natural color oxidation; aluminium plate needs to be sprayed after chromate oxidation treatment spraying. Surface pretreatment can clean the surface, significantly improve the adhesion of the film, and can double the corrosion resistance of the film. The cleaning process first cleans the workpiece, first hangs the workpiece on the assembly line, first passes through the cleaning solution (alloy degreasing powder), then enters the clean water, secondly passes through the spray area, then passes through the drying area, finally takes the workpiece off the assembly line.

After processing before the table, it enters the spraying process. When the workpiece requires spraying after assembly, the teeth or part of the conductive holes need to be protected. The holes can be inserted into the soft rubber rod or screwed into the screw. The high temperature tape should be used for conductive protection. A large number of positioning fixtures should be made to locate the protection. In this way, the spraying will not be sprayed inside the workpiece and the nut (flanging) holes can be seen on the outer surface of the workpiece. Screws are used to protect the workpiece nut (flanging) holes from reverting teeth after spraying.

Some large batches of workpieces are also protected by tooling; when the workpieces are not assembled for spraying, the areas that do not need spraying are protected by high temperature resistant tape and paper, and some nut (stud) holes exposed to the outside are protected by screw or high temperature resistant rubber. If the workpiece is sprayed on both sides, the nut (stud) holes should be protected by the same method; small workpieces should be sprayed with lead wires or paper clips, etc. after they run together; some workpieces have high surface requirements and need to be scraped before spraying; and some workpieces should be protected by special high-temperature stickers at the grounding points. When spraying, the workpiece is first hung on the pipeline and the dust on the surface is blown away by the air pipe. Into the spraying area spraying, after spraying along the pipeline into the drying area, and finally take off the sprayed workpiece from the pipeline. There are also two kinds of spraying, manual spraying and automatic spraying, so the tooling used is different.

After spraying, it enters the assembly process. Before assembly, it is necessary to tear off the protective stickers used in the original spraying to make sure that the thread holes in the parts are not sprayed with paint or powder. During the whole process, gloves should be worn to avoid dust attaching to the workpiece, and some workpieces should be blown clean by air gun. After assembly, it enters the packaging process. Workpieces are inspected and packed in special packaging bags for protection. Some workpieces without special packaging are packed with bubble film. Before packaging, the bubble film is cut to the size of workpieces that can be packed, so as not to affect the processing speed when one side is packed while the other side is cut. Large batches can be customized.

Special cartons or bubble bags, rubber pads, pallets, wooden boxes, etc. After packing, put it into carton, and then affix the label of finished or semi-finished products on the carton.

In addition to strict requirements in the production process, the quality of sheet metal parts requires independent quality inspection. One is to strictly check the size according to the drawings, the other is to strictly check the appearance quality. Those who do not conform to the size are repaired or scratched. The appearance is not allowed to be scratched, and the color difference, corrosion resistance and adhesion after spraying are carried out. Inspection. In this way, we can find out the errors of unfolding drawing, bad habits in the process, errors in the process, such as the errors of data punch programming, mold errors and so on.

Rules

(1) Scope of application

_1 This Code is applicable to the shearing of blanks with straight edges of various ferrous metals and other similar cutting materials.

_2 The basic thickness and maximum width of the sheared material are 0.5-6 mm and 2500 mm respectively.

Materials

1 The material shall meet the technical requirements.

2 The material is cold rolled steel plate. Serious scratches, scratches, impurities and rust spots are not allowed on the surface.

Equipment and process equipment, tools.

Plates, pliers, kettles, screwdrivers, hammers.

_2 Vernier calipers, external micrometers, steel plate rulers, steel tape rulers, right angle rulers, scribing needles.

_Process preparation

Familiar with drawings and related process requirements, fully understand the geometric shape and size requirements of the parts processed.

_2 Receive the materials according to the specifications of the drawings and check whether the materials meet the requirements of the process.

3 In order to reduce consumption and improve material utilization rate, a set cutting method should be adopted for reasonable calculation.

4 The qualified materials are stacked neatly beside the machine tool.

_5 Refuel the oil holes of the shearing machine.

6 Check whether the blades of the shears are sharp and firm, and adjust the clearance of the blades according to the thickness of the sheet metal.