Customized Precision Sheet Metal Processing

Customized Precision Sheet Metal Processing

First, after receiving the drawings, our designers will select different blanking methods based on the unfolded diagram and batch size. These methods include laser, CNC punching, shearing, and die-cutting. The resulting unfolding is then performed according to the drawings. CNC punching is affected by tooling, so when processing odd-shaped workpieces and irregular holes, large burrs may appear on the edges, requiring post-processing deburring and impacting workpiece precision. Laser processing has no tooling restrictions and produces smooth cross-sections, making it suitable for processing odd-shaped workpieces. However, it can be time-consuming for smaller workpieces. Placing a workbench next to the CNC and laser machines facilitates sheet metal placement on the machines for processing, reducing the amount of sheet metal lifting required. Some usable offcuts are stored in designated areas to provide material for trial molds during bending. Second, after blanking, the workpiece undergoes necessary trimming of edges, corners, burrs, and joints. Flat files are used to trim tool joints, while larger burrs are trimmed with a grinder. Small internal holes are trimmed with corresponding small files to ensure a beautiful appearance. This trimming also ensures consistent positioning during bending, ensuring consistent positioning of the workpiece against the press brake and consistent dimensions across the entire batch.

Third, after blanking is complete, the workpiece enters the next process, with each process depending on the specific processing requirements. These include bending, riveting, flanging, tapping, spot welding, embossing, and stepping. Sometimes, nuts or studs need to be pressed after one or two bends. Embossing and stepping areas should be processed first to avoid interference with other processes and delays in the required processing. If there are latches on the upper or lower cover that cannot be welded after bending, these should be processed before bending. Fourth, when bending, first determine the tool and tool groove based on the dimensions on the drawing and the material thickness. Avoiding deformation caused by collision between the product and the tool is crucial for selecting the upper die. The choice of the lower die is determined by the thickness of the sheet. Secondly, determine the order of bending. Generally, bend the workpiece inwards first, then outwards, small parts first, then large parts, and special parts first, then standard parts. For workpieces that require crimping, first bend the workpiece to 30°-40°, then press the workpiece with a flattening die. When riveting, consider selecting dies of varying stud heights and adjusting the press pressure to ensure the stud is flush with the workpiece surface. This prevents the stud from being pressed in or protruding beyond the workpiece surface, resulting in scrapped workpieces.

Fifth, welding includes argon arc welding, spot welding, CO2 shielded welding, and manual arc welding. For spot welding, the first consideration is the workpiece's position. In mass production, consider installing positioning tooling to ensure accurate spot welding positions. To ensure a secure weld, the workpieces are embossed with raised points. This ensures uniform heating at all points before welding, and also helps determine the weld position. Similarly, the pre-pressing, hold, hold, and rest times must be carefully adjusted to ensure a secure spot weld. Spot welding can leave weld scars on the workpiece surface, which require a flat grinder. Sub-arc welding is primarily used when joining two large workpieces or for finishing the edges and corners of a single workpiece to achieve a smooth, flat surface. The heat generated by sub-arc welding can easily cause workpiece deformation, so post-weld treatment with a grinder or flat grinder is recommended, especially for corners with numerous edges.

Sixth, after bending, riveting, and other processes, the workpiece requires surface treatment. Treatment methods vary depending on the plate. Cold plate processing typically involves electroplating, but spraying is not performed after this. Instead, phosphating is used, followed by spraying. Electroplated plates are cleaned and degreased before being sprayed. Stainless steel sheets can be brushed before bending, without spraying. If spraying is required, roughening is required. Aluminum sheets are generally oxidized, with different oxidation base colors selected depending on the desired color. Black and natural oxidation are commonly used. Aluminum sheets that require spraying are chromated before spraying. This surface pretreatment cleans the surface, significantly improving coating adhesion and doubling the corrosion resistance of the coating. The cleaning process begins by washing the workpiece. The workpiece is hung on the assembly line, first immersed in the cleaning solution, then in clean water, then passed through the spray area, and then through the drying area. Finally, the workpiece is removed from the assembly line.