Sheet metal is one of the most commonly used materials in product structural design.
This article provides a detailed overview of the principles for selecting sheet metal materials, including cold-rolled thin steel plates, electro-galvanized cold-rolled thin steel plates, hot-dip galvanized thin steel plates, aluminum-zinc-coated plates, and stainless steel plates, along with their applications in the structural design of communication products. Additionally, it discusses the impact of materials on processes such as punching, bending, and stretching, emphasizing the importance of material properties like plasticity, yield strength, and hardness. The article also explores the process design for punching and blanking, covering common methods, secondary cutting, bending radii, springback phenomena, and structural forms of nuts and screws. Lastly, it touches on other technical details like stretching, embossing, localized recesses, and pressing lines, providing comprehensive guidance for sheet metal processing.
1. Sheet Metal Material Selection
Sheet metal is the most widely used material in the structural design of communication products. Understanding material properties and selecting the right materials is crucial for reducing product costs, improving performance, ensuring quality, and optimizing manufacturability.
1.1 Principles of Material Selection
Use commonly available metal materials to reduce material specifications and varieties, ensuring they are within the company’s material handbook.
Minimize the variety of materials and thickness specifications within the same product.
Opt for economical material types that meet functional requirements while reducing material consumption and cost.
For large cabinets and enclosures, consider ways to reduce the overall weight of the assembly.
Beyond ensuring functional requirements, ensure the material’s stamping performance meets processing needs to guarantee reasonable manufacturing and product quality.
2. Overview of Common Sheet Materials
2.1 Steel Plates
Cold-Rolled Thin Steel Plates
Cold-rolled thin steel plates, also known as carbon structural steel cold-rolled sheets, are produced by further rolling hot-rolled steel strips at room temperature to create sheets less than 4mm thick. The absence of scale during rolling results in superior surface quality and dimensional accuracy. Combined with annealing, these plates offer better mechanical and processing properties than hot-rolled sheets.
Electro-Galvanized Cold-Rolled Thin Steel Plates
Known as “electroplated sheets,” these plates feature a zinc coating applied through an electrolytic process. The coating is thin due to process limitations, but the material provides corrosion resistance suitable for various applications.
Hot-Dip Galvanized Thin Steel Plates
Often referred to as galvanized sheets, these are produced by immersing cold-rolled steel in molten zinc at temperatures of 450–460°C. They feature good corrosion resistance and are commonly used in communication equipment.
Aluminum-Zinc-Coated Plates
These plates have an alloy coating composed of 55% aluminum, 43.4% zinc, and 1.6% silicon. The dense quaternary crystal structure provides excellent corrosion resistance, with a lifespan of up to 25 years, comparable to stainless steel. They are widely used in communication equipment without the need for additional plating or painting.
Stainless Steel Plates
Stainless steel offers high corrosion resistance, conductivity, and strength, making it widely used. However, its disadvantages include high cost (four times that of galvanized steel), high tool wear during CNC punching, and expensive fasteners such as high-strength stainless steel rivet nuts. Additional welding may be required to secure rivet nuts.
2.2 Aluminum and Aluminum Alloy Plates
3A21 (LF21)
This AL-Mn anti-rust aluminum alloy is widely used due to its moderate strength and high plasticity, especially in annealed conditions.
5A02 (LF2)
This AL-Mg anti-rust aluminum alloy features higher strength, good fatigue strength, and excellent corrosion resistance, often used in applications requiring higher durability.
2A06 (LY6)
A common hard aluminum alloy with high strength and hardness, suitable for flat panels but not for bending due to its poor plasticity, which may lead to cracking.
2.3 Copper and Copper Alloy Plates
T2 Copper (Pure Copper)
Known for its excellent conductivity, thermal performance, and corrosion resistance, T2 copper is often used in components that require high electrical conductivity, such as power supply parts.
H62 Brass
A high-zinc brass alloy with good strength, corrosion resistance, and cold and hot processing properties. While its conductivity is lower than pure copper, it offers sufficient strength and is more economical, making it a preferred substitute for T2 copper when possible.
These materials represent the primary sheet metals used in the majority of industries, meeting 99% of market needs. For more information about sheet metal processing, stay updated with Mulan Trade Group, a leading sheet metal manufacturing service provider in China. We continually update industry information for user reference.
