Forming, redistribution and addition processes Paper and board forming processes - Metal processes — AQA A-Level Design and Technology: Product Design
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Forming, redistribution and addition processes Paper and board forming processes - Metal processes explained
Press forming reshapes sheet metal by clamping a blank between a die and a punch and forcing the punch into the die cavity, so the metal flows plastically into a three-dimensional shape without deliberately removing material.
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It suits high-volume production of consistent parts such as car panels, cookware and enclosures. The blank is located, held by a blankholder or clamp, then the punch descends; clearance between punch and die controls wall thickness and prevents tearing or wrinkling. Deep draws may need more than one stage, and ductile metals such as mild steel, aluminium and copper form more readily than brittle ones. Lubricant reduces friction and galling. The process is a redistribution process: volume is conserved while shape changes.
Your focus
- Describe how a sheet metal blank is clamped and forced into a die cavity by a punch during press forming.
- Explain why press forming is classified as a redistribution process with conserved volume.
- Identify suitable products and material properties, such as ductility, for successful press forming.
Forming, redistribution and addition processes Paper and board forming processes - Metal processes exam tips
Marking Points
- Identifies press forming as a metal forming process in which a sheet blank is clamped and a punch forces it into a die cavity, reshaping rather than cutting the metal.
- Recognises that the metal is redistributed plastically with volume conserved, so the process belongs to redistribution rather than addition or wasting.
- Links the process to high-volume, repeatable production of three-dimensional parts such as car body panels, cookware or enclosures.
- Explains the roles of punch, die and blankholder/clamp, including how clearance and holding force control wall thickness and reduce wrinkling or tearing.
- Notes that material ductility and lubrication affect formability, and that deep shapes may require multiple stages.
Examiner Tips
- 💡Name the tooling explicitly (punch, die, blankholder) and state what each does, rather than describing the process vaguely.
- 💡Use the phrase 'redistribution process' and explain that volume is conserved while shape changes.
- 💡Give a named product example such as a car door panel to show the process suits high-volume three-dimensional parts.
Common Mistakes
- Confusing press forming with press cutting or blanking: press forming reshapes the sheet by plastic flow, whereas blanking cuts a shape out of the sheet.
- Assuming material is added or removed: press forming conserves the metal volume and only changes its shape, so it is a redistribution process.
- Ignoring the blankholder: without clamping, the sheet can wrinkle or draw in unevenly, so the hold-down function must be recognised.