Choose according to factors such as the product's use environment, strength requirements, and cost budget. For example, galvanized steel plates or stainless steel plates are preferred in humid environments; high-strength cold-rolled or hot-rolled steel plates are selected for high strength requirements; ordinary cold-rolled steel plates can be selected for cost considerations and ordinary environments; aluminum plates can be used for weight-sensitive products.

Sheet metal materials have a wide range of thicknesses. Common cold-rolled steel plates range in thickness from 0.3mm to 6.0mm, aluminum plates generally range in thickness from 0.5mm to 5.0mm, and stainless steel plates range in thickness from about 0.2mm to 8.0mm. Different manufacturers and uses have different common specifications.

The bending radius depends on the material thickness and material properties. Generally speaking, the bending radius should not be less than the material thickness, otherwise it may cause cracks at the bend. For different materials, such as stainless steel, the minimum bending radius is relatively large, while that of soft aluminum plates is relatively small.

The size of the hole should take into account the processing technology. For example, the minimum hole diameter of the punching hole is generally not less than the plate thickness. The hole spacing should ensure that the hole margin is sufficient to prevent deformation or cracking during processing or use. Usually, the hole margin is not less than 1.5 times the plate thickness.

Minimize the number of parts, use simple shapes and structures, and avoid overly complex bends and contours. Reasonably plan the distribution and size of holes to reduce the number of processing steps and molds used. For example, holes designed to a universal size can be processed with the same mold.

Commonly used methods include laser cutting, plasma cutting, shearing machine cutting, etc. Laser cutting has high precision and a smooth cutting surface, which is suitable for fine processing and thin plate cutting; plasma cutting has a faster speed and can cut thicker plates, but the cutting surface is relatively rough; shearing machine cutting is suitable for straight-line cutting and mass production, and the precision is average.

Laser cutting has high precision, generally up to ±0.1mm - ±0.5mm, and the specific precision depends on factors such as equipment performance, material thickness, and operator skills.

Plasma cutting can cut thicker sheet metal materials, generally steel plates with a thickness of about 0.5mm - 100mm, but as the thickness increases, the cutting precision and speed will decrease.

Generally, the bending angle tolerance is between ±1° - ±3°. Products with high precision requirements can be controlled within ±0.5°, which is related to the accuracy of the bending equipment, mold quality, and operating process.

Installing appropriate protective devices on the bending die, such as polyurethane rubber pads, can reduce friction on the sheet metal surface. At the same time, keep the bending die clean and smooth to prevent impurities from scratching the sheet metal.

Multiple bending may cause sheet metal materials to harden, reduce their toughness and ductility, and increase the risk of cracks. Some material properties can be restored through intermediate annealing, but it will increase costs and processing cycles.