Planning for CNC Operations

1
Planning for CNC Operations
2
Coordination of 5 functions

• 1. NC management - shop supervisor
• 2. Part programming - programmer
• 3. Machine operators
• 4. Tool and fixture preparation - tool room
  person
• 5. Machine and controller maintenance

3
Process planning - detailed operation plan

• person often called a process planner
• links engineering design with shop floor machining

4
Planning considerations (6)
5
1. Raw material considerations

• size and shape
• amount of material to be removed

6
2. Datum Selection

• reference surfaces for machining and mating parts

7
3. Process capability

• holding tolerances
• surface finish quality

8
4. Process selection and sequencing (p129)
9
5. Tool path planning
10
6. Machining parameters

• speeds, feeds, depth of cut
• depth of cut determined by available spindle
  horsepower and rigidity of cutter and machine

11
NC documentation (6)
12
1. Raw material drawings

• specs on material type
• shape and dimensions of the blank

13
2. Production drawings
14
3. Operation sheet

• required processes
• sequences

15
4. Tooling plan

• list of tools (p157)
• offsets (p160)
• presets

16
5. Workholding and machine setup sheet

• locating positions
• clamping positions
• clamping methods
• list of locating and clamping devices
• special notes - clamping forces, pressures

17
6. Programming sheet