4.2 Sheet metal processes

• Sheet metal processes: edge treatment, hollowing, sinking, raising
• Tools and equipment for sheet-metal processes
• Carrying out sheet-metal processes
• The importance of sheet-metal processes

• describe the sheet-metal processes applied in metal technology
• select tools and equipment for a given sheet-metal process
• carry out sheet-metal processes for a given task
• acknowledge the importance of sheet-metal processes in day-to-day life

“Why are sheet-metal processes important?”

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1. Shaping sheet without cutting it
   40 min · 1 practice tasks · quiz
   The four sheet-metal processes, and why a shaped article with no seam beats one cut and joined.
2. Stretching and shrinking
   40 min · 1 practice tasks · quiz
   The only two things that can be done to sheet without cutting it, and why stretching has a limit that shrinking does not.
3. Why raw edges must be treated
   40 min · 1 practice tasks · quiz
   The three faults of a sheared edge, and the four treatments that fix all of them at once.
4. Forming a safe edge
   40 min · 1 practice tasks · quiz
   Marking the allowance, folding to a right angle and closing the fold, and why the allowance must be added when marking out.
5. Forming a wired edge
   40 min · 1 practice tasks · quiz
   Turning a curl, laying the wire in and closing the metal round it, and why the allowance is 2.5 times the wire diameter.
6. Beading and swaging
   40 min · 1 practice tasks · quiz
   Rolling grooves into sheet to stiffen it, the difference between a bead and a swage, and why a groove works so well.
7. Hollowing
   40 min · 1 practice tasks · quiz
   Beating a depression into flat sheet over a hollow support, working in a spiral, and recognising work hardening.
8. Sinking
   40 min · 1 practice tasks · quiz
   Beating the middle of a clamped sheet down inside a former, leaving a flat flange, and the two faults that spoil it.
9. Raising
   40 min · 1 practice tasks · quiz
   Forming deep shapes by beating from the outside and shrinking the metal, and why raising can go where hollowing cannot.
10. Planishing
    40 min · 1 practice tasks · quiz
    Smoothing a shaped surface with light overlapping blows between polished faces, and why it also stiffens the work.
11. Stakes and formers
    40 min · 1 practice tasks · quiz
    The stakes that support sheet work from behind, how the shape of the stake decides the shape you can form, and how to look after them.
12. Hammers and mallets for sheet work
    40 min · 1 practice tasks · quiz
    Which tool moves metal without marking it, which finishes it, and why a steel hammer ruins thin sheet.
13. Work hardening and annealing
    40 min · 1 practice tasks · quiz
    Why hammered sheet becomes hard and springy, how to recognise it, and how to soften each metal again.
14. Choosing the process for a shape
    40 min · 1 practice tasks · quiz
    Working from the shape you want back to the process that makes it, and the two processes that apply to every job.
15. A shaping task: making a scoop
    40 min · 1 practice tasks · quiz
    Bringing the processes together on one article, in an order that cannot be changed.