Shaping

Question 1

Define shaping (simple).

Answer 1

Changing a material’s form/geometry without removing material, e.g., bending, folding, rolling, press/forming, spinning, thermoforming.

Question 2

What is bending/folding of sheet metal?

Answer 2

Deforming sheet along a straight line to a set angle using a pan folder/press brake and a former or vee die.

Question 3

Name two bench tools for light sheet bends.

Answer 3

Hand seamer (sheet-metal pliers) and a pan folder (box and pan brake).

Question 4

What is a press brake used for?

Answer 4

Accurate bends in sheet/plate using a punch and vee die; suits repeated production with backstops/NC control.

Question 5

Minimum bend radius—why important?

Answer 5

Too-tight bends crack material or thin the outer fibres; choose radius ≥ material guidelines to reduce cracking and springback.

Question 6

What is springback?

Answer 6

Elastic recovery after bending that reduces angle; over-bend slightly or use corrected tooling to hit the target angle.

Question 7

What is rolling?

Answer 7

Passing sheet or bar through rollers to curve it to a radius; three‑roll bending machines set the centre roll to adjust radius.

Question 8

Name two checks after bending a bracket.

Answer 8

Check angle with a protractor/angle gauge and measure flange lengths; verify symmetry against a drawing or jig.

Question 9

What is metal spinning (school‑level)?

Answer 9

Forming a rotating sheet blank over a mandrel on a lathe using a roller/tool to create axisymmetric shapes (e.g., cones, bowls).

Question 10

Two basic forging terms.

Answer 10

Drawing‑out (lengthen, reduce section) and upsetting (shorten, increase section) using compressive force.

Question 11

What is annealing and why before shaping aluminium?

Answer 11

Heat then cool to soften/work‑hardened metal, reducing cracking risk and force needed for bending/pressing.

Question 12

Thermoplastics vs thermosets—shaping difference (simple).

Answer 12

Thermoplastics soften with heat and can be reshaped (e.g., acrylic); thermosets are set permanently and don’t soften again.

Question 13

What is line bending (acrylic)?

Answer 13

Heating a narrow line with a strip/line bender then folding over a former/jig to a set angle; hold until cool to fix the shape.

Question 14

Why use a former/jig for line bends?

Answer 14

Ensures consistent angle and position across a batch; improves accuracy and safety for students.

Question 15

What is vacuum forming?

Answer 15

Heating a thermoplastic sheet until soft, then using vacuum to draw it over a mould (former); trim after forming.

Question 16

Two design tips for vacuum forming formers.

Answer 16

Add draft (taper) and radiused corners to aid release and reduce thinning/tearing.

Question 17

Drape forming—simple definition.

Answer 17

Softened sheet is laid over a mould and allowed to sag/pressed to shape under gravity or light pressure.

Question 18

Steam bending wood—what does steam do?

Answer 18

Plasticises lignin so timber can be bent around a former; clamp until dry to set the curve.

Question 19

Lamination in shaping—what is it?

Answer 19

Gluing thin layers over a form to build a curved shape; layers resist springback and give strength.

Question 20

Why use jigs/fixtures in shaping?

Answer 20

To locate and support work during bending/pressing so parts are safe, repeatable, and within tolerance.

Question 21

Name three PPE/safety points for sheet‑metal shaping.

Answer 21

Gloves for sharp edges (as appropriate), eye protection, and keep hands clear of pinch points/rollers and press tooling.

Question 22

Two hazards specific to line bending/vacuum forming.

Answer 22

Burn risk from heaters/hot plastic and fume risk—use extraction and heat‑resistant gloves as needed.

Question 23

What is a pinch point and where found?

Answer 23

A trapping gap between moving parts, common on rollers and press brakes—guard and keep clear.

Question 24

Two simple gauges for shaped parts.

Answer 24

Angle gauge/protractor for bends and radius gauges/templates for curves/edges.

Question 25

How to check a rolled ring’s roundness quickly?

Answer 25

Measure diameter in several directions or sit it in a V‑block and watch for gaps; adjust and re‑roll if needed.

Question 26

What drawing info helps shaping accuracy?

Answer 26

Include bend radii, bend positions from a datum, inside/outside dimensions, and tolerances on angle/length.

Question 27

Shaping vs wasting—difference.

Answer 27

Shaping changes form without removing material; wasting removes material (e.g., cutting, drilling, milling).

Question 28

Choose a process: make 30 identical acrylic stands with 90° bends.

Answer 28

Line bending with a stop/former for repeatability; check angle with a jig and cool before release.

Question 29

Choose a process: produce a curved aluminium panel (large radius).

Answer 29

Three‑roll bending with progressive passes; check radius with a template and allow for springback.

Question 30

Choose a process: form a domed plastic cover in class.

Answer 30

Vacuum forming over a smooth radiused mould; drill vents in deep pockets to aid draw‑down.

Question 31

Two common bending defects and fixes.

Answer 31

Cracking on outside fibres (increase radius/anneal), and twist/warping (square up in a press, use a proper former).

Question 32

Vacuum forming defect: webbing—cause and fix.

Answer 32

Excess material bridging between features; fix with better mould spacing, radius changes, or lower sheet temperature/earlier vacuum.

Question 33

Vacuum forming defect: thinning—cause and fix.

Answer 33

High draw depth/sharp corners; reduce depth, add draft/radii, or pre‑stretch the sheet (plug assist).

Question 34

Bend allowance (simple idea).

Answer 34

Extra material length needed in the bend region; use trial pieces or data from charts/jigs at L1/2 level.

Question 35

Where to measure flange length—inside or outside?

Answer 35

State clearly on the drawing; inside dimensions need added allowance for radius and material thickness.

Question 36

How does shaping link to Lean (TIMWOOD)?

Answer 36

Use formers/stops to cut Defects and Overprocessing; plan nests/batches to reduce Waiting and Motion.

Question 37

First‑article approach for a bend setup—what is it?

Answer 37

Make one part, measure angle/lengths, adjust stops/over‑bend as required, then run the batch.

Question 38

Two pre‑use checks on a press brake/pan folder.

Answer 38

Guards/interlocks working and tooling tight/undamaged; set backstops with machine isolated.

Question 39

Edge finishing after shaping—why deburr?

Answer 39

To remove sharp edges that cut hands or snag; improves safety and assembly fit.

Question 40

Good thermoplastics for line bending/vac forming (two).

Answer 40

Acrylic (PMMA) and HIPS/ABS; both soften with heat and set on cooling.

Question 41

Metals suitable for school bending/rolling (two).

Answer 41

Aluminium and low‑carbon steel—ductile and available in sheet/strip.