What is sheet metal?
Sheet metal is a comprehensive cold processing process for metal sheets (usually less than 6mm), including shearing, punching/cutting/combining, folding, welding, riveting, splicing, and forming.
Features:
1.Uniform thickness. For a part, the thickness of all parts is consistent.
2.Light weight, high strength, electrical conductivity, low cost, good performance in large-scale mass production
Processing Technology
1.Cut
The equipment for the shearing process is a shearing machine, which can cut a metal sheet into basic shapes. Advantages: low processing cost; Disadvantages: average precision, burrs when cutting, and single cutting shapes, all of which are simple rectangles or other simple figures composed of straight lines.
The unfolded size of the parts must be calculated before the cutting process. The size of the unfolded size is related to the bending radius, bending angle, sheet material, and sheet thickness.
2.Rush
The equipment for the punching process is a punch press, which can further process the cut materials into shapes. Different molds are required for stamping various shapes. Common molds include round holes, oblong holes, and bosses; they have higher precision.
Boss: The material is not removed. Note that the height of the boss is limited, which is related to the material of the plate, the thickness of the plate, the angle of the boss bevel, etc.
There are many kinds of bosses, including heat dissipation holes, mounting holes, etc. Due to the influence of bending, the edge of the designed hole is limited from the edge of the plate and the bending edge.
3.Laser cutting
Processing equipment: laser cutting machine
For materials that cannot be removed by shearing or punching, or for plates with high hardness that are easy to damage the mold, such as those with rounded corners, or when there is no ready-made mold to punch the required shape, laser cutting can be used to complete the forming of the material before bending.
Advantages: burr-free cutting, high precision, and can cut any graphics, such as leaves, flowers, etc. Disadvantages: high process cost
4.Bending
Processing equipment: Bending machine, plate rolling machine
They can fold or roll metal sheets into the required shape, which is a forming process for parts. The process of cold pressing the metal sheet with the upper and lower knives of the bending machine to deform it and obtain the required shape is called bending.
Bending is the last step in sheet metal forming. There are several points that need to be paid attention to whether the parts can be unfolded and bent.
1.Lack of materials. As shown in the figure below, the boss is too high, exceeding the ductility of the material. The boss is generally used to raise the installation size or avoid installation conflicts, so the boss must be made without changing the internal structure of the material and affecting the structural strength. For example: the angle between the boss cone and the reference plane is 45°, and the height is 3 times the thickness of the plate.
2.Redundant materials: Redundant materials are often found at places where multiple bending edges are closed, which is mostly due to process errors or drawing errors.
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 blade. The solution can be multi-sided large angle bending
Double-side 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 subject to restrictions on the bottom side: bending height < bottom side
4.Since sheet metal parts are formed by bending a piece of thin metal plate, the contact of the bent edge is not sealed and there is no hard connection. If it is not handled, it will affect the strength. The usual treatment method is welding. The technical requirements on the drawing are: welding angle, welding angle, rounding
5.Surface treatment
Since sheet metal parts are relatively thin, they are not suitable for hot-dip galvanizing. Common surface treatment methods include: phosphating, electrostatic spraying, and the color varies with the project. This process is suitable for black parts with untreated surface.
