Sheet Metal Fabrication
What is a sheet metal part?
Sheet metal parts are a comprehensive cold working process for metal sheets (usually less than 6mm), including shearing, punching/cutting/compounding, folding, welding, riveting, splicing, forming, and parts made
1. Uniform thickness. For a part, the thickness of all parts is the same
2. Lightweight, high strength, electrical conductivity, low cost, and good mass production performance
B. Processing technology
The equipment for the cutting process is a shearing machine, which can cut a sheet of metal into a basic shape. Advantages: low processing cost; Disadvantages: general accuracy, cutting with burrs, cutting shapes are simple rectangles or other simple straight lines Composition of graphics.
The unfolded size of the part must be calculated before the cutting process. The unfolded size is related to the bending radius, bending angle, sheet material, and sheet thickness.
The equipment of the punching process is a punching machine, which can further process the cut material into shape. Stamping various shapes requires different molds. Common molds have round holes, long round holes, and bosses; the accuracy is higher.
Boss: The material is not removed. Note that the height of the boss is limited, which is related to the material of the board, the thickness of the board, and the angle of the slope of the boss.
There are many kinds of bosses, including heat dissipation holes, mounting holes, and so on. Due to the influence of bending, the distance between the edge of the design hole and the edge of the plate and the bending edge will be limited
3) Laser cutting
Processing equipment: laser cutting machine
For materials that cannot be removed by cutting or punching processes, or plates that are harder to damage the mold, such as rounded corners, or when there is no ready-made mold to stamp the required shape, laser cutting can be used to complete the material before bending. Molding
Advantages: cutting without burrs, high precision, can cut any graphics, such as leaves, flowers, etc.; Disadvantages: high process cost
C. Processing equipment: bending machine, bending machine
They can bend or roll the metal sheet into the required shape, which is the forming process of parts; the process of cold pressing the metal sheet by the upper and lower knives of the bending machine to deform the metal sheet to obtain the required shape is called bending.
Bending is the last step in the forming of sheet metal parts. There are a few points that need to be paid attention to whether the parts can be unfolded and bent.
5 points to note when bending
1. The material is lacking, as shown in the figure below. The boss is too high and exceeds the ductility of the material. The boss is generally used to increase the installation size or avoid installation conflicts, so the boss must not change the internal structure of the material or affect the structural strength. It can only be produced under circumstances. For example: the angle between the boss cone and the reference plane is 45°, and the height is 3 times the plate thickness
2. Redundant materials: redundant materials are common where multiple bending edges are closed, and most of them are process errors or
3. Bending restrictions: most bending machines have certain restrictions on bending
Single-side height: depends on the size of the bending machine and the height of the upper knife, the solution can be multilateral large-angle bending
Bilateral height: not greater than the maximum height of a single side, in addition to all restrictions on the height of a single side, it is also restricted by the bottom side: bending height <bottom side
4. Since the sheet metal part is formed by bending a thin metal plate, the contact of the bending edge is not sealed and there is no hard connection. If it is not processed, the strength will be affected. The usual processing method is welding. The technical requirements on the drawing are: welding angle, Fillet, rounding
5. Surface treatment
As the sheet metal of sheet metal parts is thin, it is not suitable for hot-dip galvanizing. Common surface treatment methods are: phosphating, electrostatic spraying, and the color depends on the project. This process is suitable for black parts with an untreated surface.