17 Other forming processes - 1

1. Deep drawing is mainly used to produce: A. Open channels. B. Closed cylindrical or rectangular containers. C. Flat plates. D. Welded assemblies.

2. The sheet metal blank used in deep drawing is typically: A. Square. B. Hexagonal. C. Disc‑shaped. D. Tubular.

3. The blankholder’s function is to: A. Cut the sheet. B. Hold the blank perimeter against the die. C. Heat the blank. D. Increase punch speed.

4. During deep drawing, the punch first deforms the blank by: A. Stretching. D. Bending to form a cup. C. Shearing. B. Twisting.

5. The blankholder force must be: A. Maximized at all times. B. Completely removed. C. Partially released to allow sheet sliding. D. Applied only at the end.

6. Light drawing occurs when the height is: A. Equal to the diameter. D. Less than 1.5 times the diameter. C. More than twice the diameter. B. Independent of diameter.

7. In deep drawing, thickness reduction mainly occurs in: A. The punch contact area. B. The flange. C. The vertical walls. D. The blank perimeter.

8. The Limiting Drawing Ratio (LDR) depends primarily on: A. Sheet color. B. Material ductility or fragility. C. Punch speed. D. Die temperature.

9. Once tools are manufactured, the most critical parameters to control are: B. Punch hardness and sheet color. A. Lubrication and blankholder pressure. C. Punch speed and sheet coating. D. Die temperature and sheet width.

10. At the base of the cup, the stress state is: A. Pure compression. B. Pure shear. C. Tension in all directions. D. Zero stress.

11. In the vertical walls, the circular mark elongates because: A. There is tension vertically and little circumferential stress. B. Compression dominates in all directions. C. Shear stresses are maximum. D. The punch rotates.

12. The flange region experiences a: A. Simple tensile state. B. Pure bending state. C. Triaxial stress state. D. Zero deformation state.

13. In the flange, the circular mark becomes: B. Smaller in all directions. A. Radially elongated and circumferentially narrowed. C. Unchanged. D. Only thicker.

14. Wrinkling in the flange is caused by: A. Excessive tensile stresses. B. Circumferential compressive stresses leading to buckling. C. High punch speed. D. Excessive lubrication.

15. Tearing near the base occurs when: A. The sheet is too thick. D. Tensile stresses cause excessive thinning. C. The blankholder force is too high. B. The punch radius is too large.

16. Earing defects are caused by: A. Poor lubrication. B. Anisotropy in the sheet metal. C. Excessive punch speed. D. Incorrect blank diameter.

17. Surface scratches occur mainly due to: A. Excessive blankholder force. B. Lack of lubrication and poor cleaning. C. High punch temperature. D. Incorrect punch radius.

18. Failure limit diagrams are used to: A. Predict possible failures in deep drawn parts. B. Select punch materials. C. Determine sheet color. D. Measure punch speed.

19. Increasing blankholder force too much may cause: A. Wrinkling. B. Tearing. C. Earing. D. No effect.

20. Reducing blankholder force too much may cause: A. Excessive thinning. D. Wrinkling in the flange. C. Earing. B. Surface scratches.

21. Hydroforming involves deforming parts using: A. Compressed air only. B. Pressurized fluid. C. Mechanical hammers. D. Heated dies.

22. Sheet metal hydroforming produces parts similar to: B. Extrusion. A. Deep drawing. C. Casting. D. Rolling.

23. In sheet hydroforming, the die is replaced by: A. A steel block. B. A polymer mandrel. C. A flexible rubber membrane. D. A rotating roller.

24. During sheet hydroforming, pressure is transmitted to the blank by: A. Air jets. B. Rubber and pressurized oil. C. A heated punch. D. A rotating die.

25. One major advantage of sheet hydroforming is: A. High tooling cost. B. Poor surface finish. C. Reduced tooling cost due to flexible dies. D. Limited to long production runs.

26. Hydroforming allows deeper parts because: A. The punch moves faster. B. Fluid pressure contributes to deformation. C. The sheet is heated to melting. D. The blankholder force is eliminated.

27. Surface finish in hydroforming is excellent because: B. The punch is polished. A. The rubber membrane prevents scratches. C. The sheet is coated. D. The die is made of ceramic.

28. Tube hydroforming is used mainly to: A. Increase tube thickness. B. Modify cross‑sections for rigidity and weight reduction. C. Weld tubes together. D. Produce flat sheets.

29. Before tube hydroforming, the tube must be: A. Cast. D. Bent to fit into the die. C. Machined internally. B. Filled with sand.

30. In tube hydroforming, the tube expands because: A. The punch pushes it outward. B. The tube is heated. C. Pressurized fluid is introduced inside. D. The dies rotate.

31. A common application of hydroformed tubes is: A. Bicycle frames. B. Ship hulls. C. Forged crankshafts. D. Extruded window frames.

32. An alternative to tube hydroforming would be: A. Casting the tube. B. Welding multiple tube segments. C. Rolling the tube flat. D. Using a mandrel to compress the tube.

33. Spinning is used to form: A. Non‑axisymmetric shapes. D. Axisymmetric sheet metal parts. C. Welded assemblies. B. Extruded bars.

34. In spinning, the sheet metal disk is formed against: A. A rubber membrane. B. A rotating mandrel. C. A hydraulic punch. D. A fixed die cavity.

35. The roller tool in spinning is often made of: B. Hardened steel. A. Polymer. C. Ceramic. D. Aluminum.

36. Spinning allows greater deformation than deep drawing because: A. It uses higher temperatures. B. It is performed in a single pass. C. It gradually forms the part in multiple passes. D. It uses thicker sheets.

37. A disadvantage of spinning is: A. Poor surface finish. B. High tooling cost. C. Long processing times. D. Limited material compatibility.

38. Spinning is more efficient than deep drawing for: A. Very long production runs. B. Short and medium series. C. Only hot‑worked materials. D. Only aluminum alloys.

39. Plate roll bending cannot compete with spinning because: A. It requires expensive dies. B. It cannot create transitions between shapes. C. It produces poor surface finish. D. It cannot bend thick materials.

40. Typical products manufactured by spinning include: B. Bicycle frames and car bumpers. A. Pots, domes, nozzles, and musical instrument parts. C. Forged gears and crankshafts. D. Welded pressure vessels.

41. Die‑cutting is mainly used for: A. Large parts in short runs. B. Small parts in large runs. C. Medium parts in short runs. D. Tubular components.

42. Punching is typically used for: A. Large automotive panels. D. Medium and small parts in short or medium runs. C. Casting molds. B. Thick plates only.

43. Shearing cuts sheet metal by applying: A. Tensile stresses. B. Compressive stresses. C. Shear stresses. D. Bending stresses.

44. In shearing, cracks form: A. Only from the punch side. B. Only from the die side. C. From both punch and die sides until they meet. D. Only after heating.

45. The rollover zone in a sheared edge is: A. A rough fractured surface. B. A curved surface caused by plastic deformation. C. A sharp burr. D. A polished burnished area.

46. The burnished area appears because: B. The sheet fractures instantly. A. Material rubs against punch or die walls. C. The sheet is overheated. D. Clearance is too large.

47. The burr is located: A. At the top of the cut. B. At the punch entry. C. At the bottom, near the die contact. D. In the middle of the thickness.

48. Typical cutting clearance values are: A. 1–3% of sheet thickness. B. 8–15% of sheet thickness. C. 20–25% of sheet thickness. D. 30–40% of sheet thickness.

49. Smaller cutting clearance results in: B. Worse edge quality. A. Better edge quality. C. More burr formation. D. Higher fracture zone.

50. Soft materials require: A. Larger clearances. D. Smaller clearances. C. No clearance. B. Clearance equal to sheet thickness.