Xun #1

Question 1

What is the definition of process planning?

Answer 1

Process planning can be defined as the systematic determination of the methods by which a product is to be manufactured economically and competitively

Question 2

What are the two basic activities involved in process planning?

Answer 2

Determinitation of a macro plan based on machine tools, then decomposition of macro-plan into specific machining operations related to a single tool use - called a micro plan.

Question 3

What are the six basic steps of production planning? Which steps fall under macro planning and micro planning?

Answer 3

Question 4

The second step in process planning is called “raw workpiece”. What are three major considerations here?

Answer 4

1. Material - depends on functional requirements of part and cost
2. Shape - e.g. rod, slab, billet, etc
3. Size - depends on dimensional accuracy and form of workpiece

Question 5

The first step in developing a process plan is called “Part Requirements”. What does this step involve?

Answer 5

This step simply involves identifying the most important design features and manufacturing features for the part, such as the geometrical and technical requirements which will be imporant later on

Question 6

“Manufacturing Operations and Sequences” is the third step in developing a process plan. What are two major considerations here?

Answer 6

1. The part - required surface finish, tolerance requirements, feature accessibility and workpiece setup, production volume, etc
2. Machine tools and cutting tools - availability and capability

Question 7

What is the ISO tolerance grade? How many grades of accuracy are there? How does tolerance vary with IT number?

Answer 7

It is a group of tolerances (grades of accuracy) that vary depending on the basic size, but provide the same relative level of accuracy within a grade

20 grades of accuracy (IT01, IT0, IT1, IT2, … , IT18)

The smaller an IT number, the tighter the tolerance and hence the greater the accuracy

Question 8

What are common uses for the following ranges of tolerance?

IT1 to IT6

IT5 to IT12

IT11 to IT16

IT16 to IT18

Answer 8

IT1 to IT6 - Gauges and measuring instruments

IT5 to IT12 - For fits in precision and general engineering

IT11 to IT16 - Production of semi-products

IT16 to IT18 - For structures

Question 9

What is the notation used in the ISO tolerance grade?

Answer 9

Basic Dimension + Tolerance Zone (A-ZC) + IT (01 -18)

e.g. 50 H8, 50 J8, 125 H7

Question 10

What are the ISO tolerances for the following?

Answer 10

50 J8

50 H8

125 H7 (closest one)

Question 11

What is the table below used for?

Answer 11

Determining the number of machining operations required for a given feature

Question 12

“Machine Tools” is the name of the fourth step in developing a process plan. What are three major considerations?

Answer 12

1. Workpiece attributes - type of material and form, machining features, dimensions, and tolerance
2. Machine tool attributes - mode of operation (auto, manual, etc), type of operation (milling, drilling, etc), tooling capabilities
3. Production volume information - production quantity and order frequency

Question 13

What are the capabilities of the following machines:

Lathes, Mills, and Mill/Turn

Answer 13

Lathes: 2 or 4 axis turning and hole making

Mills: 3 to 5 axis milling and holemaking

Mill/Turn: 2 axis turning to 5 axis milling and holemaking