Automotive Stamping

1. Definition and Process Status

Automotive stamping is a metal-forming process where mechanical presses and dies apply external force onto sheet metal, inducing plastic deformation or separation to produce body parts of the required shapes and dimensions. It stands as the foremost of the four core manufacturing processes in vehicle assembly. Essential vehicle components such as the body shell, chassis, and fuel tank are all fabricated via stamping, accounting for approximately 60% to 70% of the world's steel sheets requiring stamping and forming.

2. Classification of Stamping Operations

Stamping operations are primarily categorised into two types based on the nature of deformation:

Separation processes: The sheet metal is cut along a predefined contour to achieve the desired shape and dimensions. This includes blanking (the punched-out piece is the finished part), piercing/punching (the punched-out piece is scrap), and trimming (cutting away excess material to even out formed edges).

Forming processes: The blank undergoes plastic deformation without fracturing. This includes deep drawing (forming hollow open components), flanging (forming raised edges), bending (bending along straight lines into various profiles), and restriking/sizing (refining dimensional precision).

The complete stamping sequence for body panels typically comprises five key stages: drawing, trimming, piercing, restriking, and flanging.

3. Three Core Pillars of Stamping

Automotive stamping production relies on the seamless synergy of three core elements:

• Stamping equipment: Primarily consisting of mechanical and hydraulic presses. On the 7,900T high-speed stamping line at the Xiaomo Plant, the lead press boasts a capacity of 2,500T, complemented by subsequent presses rated at 1,800T + 1,200T × 3, delivering a maximum line speed of 15 strokes per minute.

• Stamping dies: Renowned as the "king of the metalworking industry", die tooling technology serves as a key benchmark of a nation's manufacturing prowess. Body panel dies are categorised into drawing dies, trimming dies, flanging dies, and more.

• Stamping materials: Predominantly cold-rolled sheet steel; outer body panels demand an FD-grade surface finish (the primary visible surface must be entirely free of defects), while inner panels permit minor imperfections provided formability is uncompromised.

4. Industry Trends

Automation and Smart Manufacturing: Moving away from labour-intensive methods, contemporary stamping lines now feature 100% automated operations, with overall automation levels surpassing 80%. As a result, line-side manpower has shifted from large groups of general workers to dedicated technical specialists and supervisory personnel.

Dual-Cavity Tooling for Large Panels: Through enhanced press tonnage and advanced die engineering, a single press stroke can now produce two components simultaneously, doubling output efficiency while significantly driving down production costs.

Low-Noise and Green Manufacturing: With acoustic insulation and noise-dampening enclosures installed along production lines, stamping shop floor noise levels can be capped below 80 dB—among the lowest in the industry.

Adoption of Advanced Materials: The continuous drive towards vehicle lightweighting is accelerating the development of stamping processes for advanced high-strength steels, aluminium, and aluminium alloys, setting higher benchmarks for die design and forming parameters.