Empowering Manufacturing Upgrades: A Guide To Sheet Metal Processing Technology Innovation And Efficient Production Practices

Sheet metal processing lacks a complete definition to date. According to a foreign professional journal, it is a comprehensive cold processing technology for thin metal sheets (usually below 6mm), encompassing shearing, punching/cutting/compound cutting, bending, riveting, splicing, and forming (such as car bodies). Its core characteristic is that the thickness of the same part remains consistent. Metal sheet processing is sheet metal processing, and Sheet Metal Stamping Parts are thin-sheet hardware parts. They can be processed through stamping, bending, stretching, etc., with the thickness remaining unchanged during processing, distinguishing them from castings, forgings, and machined parts. Examples include car bodies and stainless steel kitchenware.

Sheet metal offers advantages such as light weight, high strength, electrical conductivity (suitable for electromagnetic shielding), low cost, and good performance for large-scale mass production. It is widely used in electronics, communications, automotive, and medical devices. For example, sheet metal is an indispensable component in computer cases, mobile phones, and MP3 players. With increasingly widespread applications, sheet metal design has become a crucial part of Stamped Sheet Metal  product development. Mechanical engineers need to master design skills to ensure that sheet metal not only meets product functional and aesthetic requirements but also simplifies stamping die manufacturing and reduces costs.

(I) Basic Equipment
Includes shearing machines, CNC punching machines, laser/plasma/waterjet cutting machines, bending machines, drilling machines, and auxiliary equipment such as uncoilers, levelers, deburring machines, and spot welders.

(II) Core Steps
Shearing: Based on the unfolded drawing and batch requirements, select a blanking method such as laser cutting, CNC punching, shearing, or die cutting to complete the initial cutting of the Stamped Sheet Metal. CNC punching is limited by the cutting tools, and when processing irregularly shaped workpieces and irregular holes, large burrs are easily generated on the edges, requiring post-processing and affecting workpiece accuracy. Laser processing has no tool limitations, produces a smooth cut, and is suitable for processing irregularly shaped workpieces, but processing small workpieces takes longer.

Punching/Cutting/Combined Processing: After blanking, the edges, burrs, and joints of the workpiece need to be trimmed (grinded). The tool joints are trimmed with a flat file, and workpieces with larger burrs are treated with a grinder. Small internal hole joints are trimmed with a corresponding small file. This ensures both a beautiful appearance and provides a guarantee for bending positioning, ensuring consistent dimensions within the same batch of Custom Metal Stampings products.

Bending/Rolling: Before Deep Drawn Metal Stamping bending, the tool and tool groove must be determined according to the drawing dimensions and material thickness to avoid product collision and deformation. The bending sequence must be clearly defined, following the rule of "inside before outside, small before large, special before ordinary." For workpieces with pressed edges, bend to 30°-40° first, then press them closed with a leveling die.

Welding: Common methods include argon arc welding, spot welding, CO2 shielded welding, and manual arc welding. Before spot welding, the welding position must be determined. In mass production, positioning fixtures can be made to ensure spot welding accuracy. To ensure a strong weld, raised dots can be made on the workpiece, and the pre-pressure time, holding time, maintenance time, and rest time should be adjusted. After spot welding, weld scars will remain on the workpiece surface, requiring treatment with a surface grinder. Argon arc welding is suitable for connecting larger workpieces or treating edges and corners. After welding, it requires treatment with a grinder and surface grinder to avoid deformation of the Precision Metal Stamping, paying particular attention to edge and corner treatment.

Surface treatment: This is a crucial step in sheet metal processing, serving both rust prevention and aesthetic enhancement purposes. It is divided into pre-treatment and post-treatment. Pre-treatment primarily removes oil, scale, and rust to prepare for post-treatment. Post-treatment includes painting (baking), powder coating, and rust-proofing. Different sheet materials for  Sheet Metal Stamping Parts require different treatment methods: Cold-rolled sheets are generally electroplated first, then phosphated, and finally sprayed. Electroplated sheets are cleaned and degreased before spraying. Stainless steel sheets (mirror, matte, brushed) can be brushed before bending and do not require spraying; if spraying is required, roughening is necessary. Aluminum sheets typically undergo anodizing, with the anodizing base color chosen based on the desired spray color (commonly black and natural). Aluminum sheets requiring spraying are chromate-oxidized before spraying.

Surface pre-treatment process: Stamped Sheet Metals are hung on the production line and sequentially pass through a cleaning solution (alloy degreasing powder), clean water, a spraying area, and a drying area before being removed. During spraying, areas that do not require spraying, such as threaded holes and conductive holes, must be protected (by inserting soft rubber rods, screwing in screws, applying high-temperature tape, etc.). For mass production, positioning fixtures can be made. Spraying methods include manual and automatic spraying. Workpieces are hung on the production line, and after air blowing to remove dust, spraying, and drying, they are removed.

Riveting: Select the appropriate mold according to the stud height, adjust the press pressure to ensure the stud is flush with the workpiece surface, and avoid workpiece scrap due to insufficient stud clamping or studs protruding beyond the Custom Metal Stampings surface.

Flanging and Tapping, Spot Welding, Embossing, and Stepping: Different workpieces enter the corresponding processes according to processing requirements. Areas requiring embossing and stepping should be processed first to avoid interference in subsequent processes. For upper or lower covers with hooks that cannot be welded after bending, these must be processed before Deep Drawn Metal Stamping bending.

In addition to strict control during production, Sheet Metal Stamping Parts require independent quality inspection: First, strictly check dimensions according to drawings, reworking or scrapping any parts with non-conforming dimensions; second, strictly inspect appearance quality, prohibiting scratches and dents, and simultaneously testing color difference, corrosion resistance, and adhesion after painting. Inspection can identify errors in the unfolded drawings, bad habits and errors in the production process (such as CNC punching machine programming errors, mold errors, etc.).