workpiece blanking

After the drawings are obtained, different blanking methods are selected according to the expansion drawings and batches, including laser, numerical control punching machine, plate shearing, mold and other methods, and then the corresponding expansion is made according to the drawings. CNC punching machine is affected by the cutting tool, for the processing of some special-shaped workpieces and irregular holes, there will be large burrs on the edge, which will have a certain impact on the accuracy of the workpiece. Laser processing has no tool limit and smooth section, which is suitable for the processing of special-shaped workpieces, but it takes a long time to process small workpieces. The workbench is placed next to the numerical control and laser, which is conducive to the processing of the sheet metal on the machine and reduces the workload of lifting the sheet. Some available edge materials are placed in designated places to provide materials for bending test molds.

After the workpiece is blanking, the corners, burrs and joints shall be trimmed (polished) as necessary. At the tool joints, flat files shall be used for trimming. For workpieces with large burrs, grinders shall be used for trimming. The small inner hole joints shall be trimmed with corresponding small files to ensure the beautiful appearance. At the same time, the trimming of the shape also ensures the positioning during bending, the position of the workpiece on the bending machine is consistent when bending, so as to ensure the consistency of the size of the same batch of products.

Next process

After the blanking is completed, the next process is entered, and different workpieces enter the corresponding process according to the processing requirements. There are bending, riveting, flanging and tapping, spot welding, convex hull and segment difference. Sometimes nuts or studs should be pressed well after bending for one or two passes. Where there are convex hull and segment difference of the mold, processing should be considered first, so as to avoid interference in other processes after processing and cannot complete the required processing. When there is a hook on the upper cover or lower shell, if it cannot be welded after bending, it should be processed before bending.

When bending, the cutting tool and groove used in bending should be determined according to the size and material thickness on the drawing. Avoiding deformation caused by collision between the product and the cutting tool is the key to the selection of the upper die (in the same product, different types of upper dies may be used). The selection of the lower die is determined according to the thickness of the plate. The second is to determine the order of bending. The general law of bending is first inside and then outside, first small and then large, first special and then ordinary. If there is a workpiece to be pressed to death, first bend the workpiece to 30-40 degrees, and then press the workpiece to death with a leveling die.

When riveting, the height of the stud should be considered to select the same and different molds, and then the pressure of the press should be adjusted to ensure that the stud and the surface of the workpiece are flush, so as to avoid the stud not being pressed firmly or pressing out beyond the surface of the workpiece, resulting in the workpiece being scrapped.

Welding includes argon arc welding, spot welding, carbon dioxide shielded welding, manual arc welding, etc. Spot welding should first consider the welding position of the workpiece, and consider positioning tooling to ensure accurate spot welding position during mass production.

In order to weld firmly, convex points are punched on the workpiece to be welded, so that the convex points can be in uniform contact with the flat plate before power-on welding, so as to ensure the consistency of heating at all points, and at the same time, the welding position can be determined. Similarly, to weld, the preloading time, holding time, maintenance time and rest time should be adjusted to ensure that the workpiece can be spot welded firmly.

After spot welding, there will be scars on the surface of the workpiece, which should be treated with a flat grinding machine. Sub-arc welding is mainly used when two workpieces are large and need to be connected together, or when the corners of a workpiece are treated to achieve smooth and smooth surface of the workpiece. The heat generated during argon arc welding is easy to deform the workpiece. After welding, it should be processed with a grinding machine and a flat grinding machine, especially in the corners.

Surface treatment

The workpiece in the bending, riveting and other processes after the completion of the surface treatment, different plate surface treatment methods are different, cold plate processing after the general surface plating, plating is not carried out after spraying treatment, the use of phosphating treatment, phosphating treatment to spray treatment. Electroplating plate class surface cleaning, degreasing, and then spraying. Stainless steel plate (mirror panel, fog panel, wire drawing plate) can be brushed before bending without spraying. If spraying is required, roughing treatment should be carried out. Aluminum plates are generally treated with oxidation, and different oxidation background colors are selected according to different colors of spraying,

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

Spraying treatment

After the surface pre-treatment, it enters the spraying process. When the workpiece is required to be sprayed after assembly, the teeth or some conductive holes need to be protected.

Protection treatment

The tooth hole can be checked into a soft rubber rod or screwed into a screw. If conductive protection is required, high-temperature adhesive tape should be attached. Positioning tooling should be made in large quantities for positioning and protection. In this way, the inside of the workpiece will not be sprayed during spraying. The nut (flanging) hole that can be seen on the outer surface of the workpiece shall be protected by screws to avoid tooth return at the nut (flanging) hole of the workpiece after spraying.

Some large-scale workpieces also use tooling protection;

When the workpiece is not equipped with spraying, the area that does not need to be sprayed shall be protected with high temperature resistant adhesive tape and paper to block some exposed nut holes with screws or high temperature resistant rubber. If the workpiece is sprayed on both sides, the nut (stud) hole shall be protected by the same method. Small workpieces are sprayed after being mixed together with lead wires or paper clips. Some workpieces have high surface requirements and should be scraped before spraying. Some workpieces are protected by special high temperature resistant stickers at the grounding symbol.

When spraying, the workpiece is first hung on the assembly line, and the air pipe is used to blow away the dust on the surface. Enter the spraying area for spraying, enter the drying area along the assembly line after spraying, and finally remove the sprayed workpiece from the assembly line.

There are two types of manual spraying and automatic spraying, so the tooling used is different.

Assembly process

After spraying, enter the assembly process. Before assembly, tear off the protective sticker used in the original spraying, and make sure that the internal thread hole of the part is not sprinkled with paint or powder. During the whole process, wear gloves to prevent dust on your hands from attaching to the workpiece. Some workpieces need to be blown clean with an air gun.

Packaging link

After assembly, it enters the packaging link. After inspection, the workpieces are put into special packaging bags for protection. Some workpieces without special packaging are packaged with bubble film, etc. Before packaging, the bubble film should be cut into the size that can package the workpiece, so as not to affect the processing speed while packaging. Special cartons or bubble bags, rubber pads, pallets, wooden cases, etc. can be customized for large batches. After packing, put it into the carton, and then paste the corresponding finished or semi-finished product label on the carton.