Materials, Standard Sizes, and Forming Processes for Sheet Metal

1. What Is Sheet Metal?

Sheet metal is made from bulk metal through processes such as rolling. Its core characteristic lies in its thickness:

The thinnest sheet metal (foil) is typically less than 0.2 mm thick. Common aluminum foil, for example, can be thinner than a hair.

Sheet metal, with a thickness range of 0.5 mm to 6 mm, offers both strength and formability at a moderate cost, making it the most widely used.

Thick plate metal, over 6 mm thick, is great for strong structures. It's perfect for things like bridge parts and heavy machinery bases.

2. Common Types and Characteristics of Metal Sheets

Metal sheets made of different materials have significantly different properties and are therefore suitable for different applications:

Ordinary steel (carbon steel) is low cost and strong. However, it rusts easily. To protect it, paint or galvanize the surface.It is primarily used in machinery housings, shelving, structural parts, and automotive chass.

Stainless steel contains chromium and nickel. These elements give it great corrosion resistance and a smooth surface.It's great for kitchen gadgets, medical tools, luxury decor, and outdoor structures.

Aluminum sheet is lightweight and has a natural oxide film. This gives it strong corrosion resistance. It also has great formability and excellent electrical and thermal conductivity. It is used in cans, electronic device housings, door and window frames, aviation components, and outdoor signage.

Copper sheet has a shiny metallic look. It offers great electrical and thermal conductivity. Plus, it resists corrosion.

3. Standard Dimension Specifications for Metal Sheet Metal

The procurement and application of sheet metal must follow standard sizes to ensure cost-effectiveness and feasibility. The following are common standard sheet metal sizes:

The importance of adhering to standard dimensions lies in:

Reduce costs: Design must plan component layout using standard dimensions. This cuts scrap and prevents material loss from parts that are too large for the standard sheet metal.

Improving Efficiency: Prioritize standard plate thicknesses to avoid high costs, long lead times, and structural risks from oversized or non-standard sheets like 1.7mm that are hard to source and process efficiently.

4. Sheet Metal Rolling Process: Hot Rolling vs. Cold Rolling

The sheet metal rolling process directly impacts its performance:

Hot rolling:

This process involves rolling heated metal billets. It provides high production efficiency and low cost. However, it leads to rougher surfaces and less precise dimensions. It works well for plates thicker than 3-5mm. It’s also good for structural parts that don't need high surface quality or exact dimensions.

Tip：Use hot rolling for thick sheets when cost matters and appearance isn’t a priority.

Cold Rolling:

Rolling hot-rolled sheet at room temperature makes it thinner and smoother. It also increases accuracy and hardness. It works well for thin metal sheets under 3-6mm thick. This is great for uses that need both looks and accuracy. Examples include automotive exteriors, electronic equipment housings, and parts for precision instruments.

Tip：Use cold rolling for thin sheets that need high precision or a great surface finish.

5. Main Processing Techniques for Metal Sheets

Processing sheet metal into specific shapes requires specialized processes:

Bending

Using a press brake and dies to apply pressure to the sheet, forming specific angles or curves is employed. This process can be used to create components such as boxes, brackets, and housings.

Stamping

This process uses a punch press with special dies to punch, cut, or emboss materials. It is efficient and ideal for producing large quantities of automotive parts and electrical components.

Deep Drawing

An advanced form of stamping, a round sheet of metal is pressed into a die using a punch to form deep-cavity containers. For example, the production of cans may require multiple stretching cycles.

Laser Cutting

Using a high-energy laser as a cutting tool, it can produce any complex shape with high precision and smooth cuts. Computer-controlled, automated operations make it suitable for small-batch, customized production.

Hemming

The application of raised or recessed ribs to the edge or surface of a sheet enhances the structural strength of thin metal sheets, prevents deformation, and creates smooth edges for improved safety and aesthetics.

6.Auxiliary Cutting Processes:

Plasma Cutting: It offers fast cutting speeds and low costs, making it suitable for thick plate processing, but its accuracy and cut finish are inferior to laser cutting.

Water Jet Cutting: Using ultra-high-pressure water mixed with abrasives to achieve cutting without a heat-affected zone, it can process a variety of materials, including metal, stone, and glass. However, its efficiency is lower and its cost is higher.

Tip: The decision should be based on a comprehensive consideration of workpiece shape, production batch, precision requirements, and budget. Laser cutting or spinning can be used for small-batch prototypes; stamping is preferred for large-volume production; roll bending is suitable for large-diameter cylinders.

Summary

Sheet metal processing relies on a comprehensive understanding of material properties, standard sizes, and manufacturing techniques. Mastering these fundamentals helps make optimal decisions throughout the design, procurement, and production processes—turning ordinary sheet metal into functional products that meet diverse needs. When examining metal products, we can also infer their manufacturing processes by analyzing their appearance, leading to a deeper understanding of the products themselves.