Manufacturing Processes - MFRG 315 - Tutorial 2


1. Describe the defects that can occur during sheet metal processes and how they may be overcome.

2. What is meant by anisotropy in sheet metal, what causes it and how and in what process might its presence be observed?

3. What shearing force is required to shear a 1m width by 3mm thick sheet of SAE 1015 steel and what is the total energy required?
(Assuming the tensile strength is 450 MPa: 1146 kN and 1719 Nm)

4. Circular blanks, do = 200 mm, are to be cut from 3 mm thick AISI 1008 steel sheet. What press force is needed and what energy is needed to cut each blank?
(Assuming tensile strength = 320 MPa [k=600, n=0.25] Ps = 513 kN, Es = 769 Nm)
(Click here for: solution).

4b. Deep drawing quality 2mm thick steel sheet with a LDR of 2.4 is to be drawn into 100 mm diameter cups with a 5 mm radius at the base.
a) Sketch the process.
b) Estimate the maximum possible blank diameter that can be drawn.
c) Estimate the maximum depth of cup that can be drawn, stating your assumptions.
(Click here for solution).

5. A low carbon steel, AISI 1008, steel container with an internal diameter of 56 mm and an internal depth of 80 mm and an internal bottom corner radius of 8 mm, is to be made by deep drawing 1.5 mm thick sheet. Assuming that the average thickness of the container equals the average blank thickness, calculate:
a) The starting blank diameter.
b) The draw sequence, assuming the first draw is made with a blank holder.
c) Estimate the press force for the first draw.
(Click here for solution: page 1, page 2, page 3).

6. What force is required to put a 90o bend in a 600mm width of 4 mm thick cartridge brass when the width of the die opening is 40mm?
(Assuming the tensile strength is 310 MPa: 74.4 kN)

7. How is a forming limit diagram produced?

8. What are the key features of:

9. What is meant by the term 'friction hill' and what causes it? - Choose an example carry out a simple analysis to determine the form of the 'friction hill'.

10. What is meant by redundant work? - show with the aid of an example the effect it has in metal forming operations.

11. Briefly discuss the relative merits of some common joining processes which may be suitable to join titanium in sheet form.

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David J Grieve, 11th December 2008.