Sheet Metal Processing: The Cornerstone of Industrial Design

In the vast field of industrial design, sheet metal processing serves as a solid cornerstone, supporting the creation of countless products. Sheet metal processing is a comprehensive cold working technique applied to metal sheets (usually under 6mm thick), encompassing a series of key steps such as cutting, stamping, bending, and welding. This process skillfully transforms metal sheets into various shapes to meet the diverse needs of different industries. With its variety of techniques, relatively low cost, and high efficiency, it holds a pivotal position in many fields.

From car bodies and doors in automotive manufacturing to enclosures and casings in electronics and electrical appliances, and even parts in the aerospace sector, sheet metal processing is omnipresent. In the automotive industry, sheet metal techniques give vehicles their smooth lines and sturdy body structures; in the electronics field, they create refined and practical enclosures that protect delicate internal components while also providing aesthetics and heat dissipation. Next, let us explore the key steps involved in sheet metal processing.

Material Selection: The Right Choice is the Best Choice
At the initial stage of sheet metal processing, material selection is crucial. The right material forms the foundation for ensuring product quality and performance. Common sheet metal materials are diverse, each with its own characteristics. Cold-rolled steel (SPCC), due to its low cost and ease of forming, is widely used in products that are cost-sensitive and have simple forming requirements, such as ordinary home appliance shells, where material thickness is generally ≤3.2mm. Hot-rolled steel (SHCC) has an advantage in thickness, T≥3.0mm, and is also commonly used for plating and painted parts. However, due to its relatively higher forming difficulty, it is mostly used for flat parts, such as flat support components in large-scale equipment.

Galvanized steel (SECC, SGCC) is divided into electrolytic N and P types. N type is mainly used in applications where surface treatment is not required, with higher cost. P type is commonly used for painted parts, playing a role in products that require good appearance and corrosion resistance, such as outdoor power distribution box enclosures. Stainless steel, known for its excellent corrosion and high-temperature resistance, is highly favored in kitchenware, medical instruments, and building decoration, such as hospital surgical instruments and kitchen sinks. Commonly used SUS304 stainless steel has outstanding corrosion resistance and mechanical properties.

Aluminum, being lightweight, corrosion-resistant, and easy to form, is an ideal choice for various lightweight sheet metal products, such as slim electronic device housings and lightweight components in aerospace equipment. Common types include pure aluminum and aluminum alloys, which can be flexibly chosen based on specific processing requirements and product applications. Copper, with excellent electrical and thermal conductivity as well as corrosion resistance, is indispensable in sheet metal processing that requires specific conductive or thermal properties, such as conductive connectors in electronic devices. Its surface is usually treated with nickel or chrome plating, or left untreated, but with a relatively higher cost.

When selecting materials, multiple factors must be comprehensively considered, including product purpose, performance requirements, cost budget, and processing difficulty. For products used in harsh outdoor environments, materials with strong corrosion resistance should be prioritized. If there are strict weight limits, aluminum is a good choice. For cost-sensitive products, cold-rolled steel or similar materials can be prioritized as long as basic performance requirements are met.

Cutting: Precisely Shaping Contours
Cutting is a key process in sheet metal fabrication that gives the material its initial shape, much like a painter sketching the first draft on a canvas. Its precision and results directly affect subsequent processing. Common cutting methods each have their own advantages. Laser cutting uses a high-energy-density laser beam to irradiate the surface of the material, causing it to melt or vaporize instantly, and auxiliary gas blows away the melted or vaporized material to achieve cutting. This method offers extremely high precision, generally controllable within ±0.1mm, with fast speed, making it especially suitable for cutting complex shapes and thin materials requiring high accuracy, such as precision housings for electronic components and fine contour cutting for aerospace parts.

Plasma cutting uses a high-temperature, high-speed plasma arc to heat the metal to a molten state, with compressed gas blowing away the molten metal to form the cut. It is more suitable for cutting thicker metal plates, generally able to handle metals over 30mm thick, and is widely used in heavy plate cutting in industries such as mechanical processing, construction, and shipbuilding. However, its precision is relatively lower, typically around ±0.5mm.

Oxy-fuel cutting uses a mixture of oxygen and fuel gas to produce a high-temperature flame that heats and oxidizes the metal, mainly used for cutting steel and similar materials. It is cost-effective but relatively slow, and the quality of the cut is greatly affected by the material’s thickness and type. Waterjet cutting uses a high-pressure water stream to shape the metal, offering strong adaptability to various materials, especially those sensitive to heat. It does not cause thermal deformation during cutting, preserving the material’s original properties, but the equipment is relatively expensive and the cutting efficiency is lower.

Different cutting methods vary significantly in precision, speed, and suitable material thickness. In practical applications, the appropriate cutting method should be chosen precisely based on factors such as the complexity of the product’s shape, dimensional accuracy requirements, and material characteristics to ensure that the cut contours meet design specifications and provide a solid foundation for subsequent processing.

Bending: Creating Unique Angles and Shapes
Bending is a crucial process in sheet metal fabrication for shaping products with unique angles and forms. By bending metal sheets along specific bend lines, the desired angles or shapes are achieved, giving the product a distinctive structure and appearance. In practical applications, CNC press brakes have become essential tools for achieving high-precision bending. Controlled by computer programs, they can accurately manage bend angles, curvatures, and bending sequences, greatly improving both the accuracy and efficiency of bending.

Controlling bend angles and curvatures is vital to product quality. Excessive bending may cause the metal to crack or deform, affecting the product's strength and appearance, while insufficient bending may fail to meet design requirements, impacting assembly and performance. Therefore, during the bending process, it is necessary to carefully select appropriate bending parameters based on sheet thickness, material characteristics, and product design requirements, such as bending force, bending speed, and die opening width.

For thicker sheets, greater bending force and suitable die opening width are required to ensure the material bends smoothly without cracking. For softer materials, the bending speed should be appropriately reduced to prevent uneven deformation caused by excessive speed. In the production of high-precision products, such as precision enclosures for electronic devices, the requirements for bending accuracy are extremely high. CNC press brakes can achieve precise program-controlled bends, allowing for small angles and complex curvatures to meet the high-precision design needs of the product.

Welding: Achieving Stable Component Connections
Welding is a key process that connects multiple sheet metal components into a complete structure, much like tightly weaving individual parts together to ensure the product's structural strength and sealing performance. Common welding methods each have their characteristics and are suitable for different materials and applications.

Arc welding uses the high temperature generated by an electric arc to melt metal for welding and is one of the most widely used welding methods. It is suitable for connecting various metal materials. The equipment is simple, operation is flexible, and it can weld in various positions and materials. However, production efficiency is relatively low, and weld quality largely depends on the skill of the operator. It is commonly used for welding large structural components where welding precision requirements are not particularly high, such as construction steel structures and large machinery frameworks.

Tungsten inert gas (TIG) welding uses argon gas as a shielding gas, effectively isolating air and preventing oxidation of the welded metal. Therefore, it is often used for welding metals prone to oxidation, such as aluminum, magnesium, titanium and their alloys, as well as stainless steel and high-alloy steel. It provides good welding results and high-quality welds, making it suitable for situations where welding quality is highly demanded, such as aerospace components and medical device welding.

Laser welding uses a high-power laser beam to melt and weld metal, offering advantages such as fast welding speed, small heat-affected zone, and minimal deformation. It is especially suitable for welding precision components, such as electronic parts and micro-device assembly, meeting high-precision and high-reliability welding requirements. However, the equipment cost is high, and it requires operators with relatively advanced skills.

Different welding methods vary in terms of suitable materials, welding results, and costs. In practice, the appropriate welding method should be chosen comprehensively based on the product's structural characteristics, material type, welding quality requirements, and budget, ensuring the welded joints are strong and reliable, meeting the product's performance and lifespan requirements.

The Art of Sheet Metal in Industrial Design
As a key part of industrial design, sheet metal processing and assembly are involved throughout the entire process, from product concept to final completion. From the initial material selection to cutting, stamping, bending, welding, and other processing techniques, and finally to assembly and quality inspection, every step embodies the wisdom and effort of engineers and technicians. They work together to create countless industrial products that are both functional and aesthetically appealing.

With the rapid advancement of technology, sheet metal processing and assembly techniques are constantly being innovated and improved. Intelligent processing equipment and automated assembly lines are gradually becoming the industry norm, significantly enhancing production efficiency and product quality while reducing labor costs and errors. The concept of green and environmentally friendly processing is also gaining traction; using new materials and eco-friendly techniques to minimize waste and pollutants has become an important direction for the sustainable development of the sheet metal industry.

In the future of industrial design, sheet metal processing and assembly will continue to play a vital role, driving product innovation and industry upgrades. They will deeply integrate with other advanced technologies, such as artificial intelligence, big data, and 3D printing, to create smarter, more personalized, and higher-performance products that meet the growing material and cultural needs of people. At the same time, with the intensifying global competition in manufacturing, sheet metal processing companies will need to continually enhance their technical skills and management capabilities, strengthen R&D innovation, and improve product quality and service levels to remain competitive in a fierce market.