Week 2: Subtractive Manufacturing Technologies

Question 1

Draw Merchant’s circle

Answer 1

Circle

Question 2

What is the definition of turning?

Answer 2

Turning operations are where metal cutting is achieved through controlled motion of the rotating the workpiece against a cutting tool (lathe/turning machine)

Question 3

What is the definition of milling?

Answer 3

Controlled motion of a rotating tool against the workpiece

Question 4

What is peripheral (slab) milling?

Answer 4

When the cutter is longer than the width of the workpiece and the rotation axis of the cutter is parallel to the surface of the workpiece

Question 5

What is conventional milling?

Answer 5

In conventional milling the maximum chip thickness is at the end of the cut as the tooth leaves the surface of the workpiece (workpiece right to left, cutter anticlockwise)

Question 6

What is climb milling?

Answer 6

In climb milling the cutting starts at the surface of the workpiece where the chip is thickest (workpiece right to left, cutter clockwise)

Question 7

What is face milling?

Answer 7

The rotating cutter has an axis perpendicular to the surface of the workpiece

Question 8

What is end milling?

Answer 8

Produces various profiles and curved surfaces

Question 9

What are the main design for machining requirements (6)?

Answer 9

• Provide access for tools
• Avoid long, thin sections that cause vibration
• Deep pockets cause vibration of the tool
• Holes can’t change direction
• Design parts that are easy to fixture
• Avoid outside rounds, which can only be CNC machined

Question 10

What are the motivations for advanced machining technologies (6)?

Answer 10

• The strength and hardness of the material are very high
• The workpiece is too brittle to be machined without damage
• The workpiece is too flexible
• The shape of the part is complex
• Special surface finish and dimensional tolerance
• The temperature rise or residual stress are not desirable or acceptable