Week 3: Transformative Manufacturing Technologies

Question 1

What is the definition of casting?

Answer 1

Casting involves pouring molten metal into a mould cavity allowing it to solidify and removing the part from the mould

Question 2

What are the advantages of casting(3)?

Answer 2

• Complex shapes with internal cavities can be produced
• Very large parts can be produced
• The process is economically competitive

Question 3

What are the main parts of a typical casting configuration (8)?

Answer 3

• Pouring cup
• Sprue
• Well
• Side riser
• Gate
• Casting
• Top riser

Question 4

What are the 3 equations that are not given for casting?

Answer 4

1. Q=Av
2. A1/A2 = sqrt(h2/h1)
3. v = c*sqrt(2gh)

Question 5

What is the desired Reynolds number?

Answer 5

Below 20,000 to avoid turbulent flow and air bubbles

Question 6

What equation is used to calculate solidification time?

Answer 6

Chvorinov’s rule

• n = 1.5 - 2
• c = constant

Question 7

What is true stress and true strain?

Answer 7

True stress = load/instantaneous area

True strain = ln(current length/initial length)

Question 8

What is forging?

Answer 8

Forging is a process in which the workpiece is shaped by compressive forces applied through various dies and tooling. Resulting parts have great strength and toughness

Question 9

What are draft angles for?

Answer 9

Draft angles are to facilitate the removal of the part from the die. Upon cooling the forging shrinks both radially and longitudinally so internal draft angles (7-10deg) are made larger than external ones (3-5deg).

Question 10

What is rolling?

Answer 10

Where rollers are used to reduce the thickness of a strip of metal

Question 11

What is the equation for power in flat rolling?

Answer 11

Power = 2piFLN/6000

- N is rpm of the roll

Question 12

What is deep drawing?

Answer 12

Where the depth of the finished part is greater than its diameter. (From a sheet of metal in one ‘punch’)