material removal processes
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Material Removal Processes
- A family of shaping operations, the common feature of which is removal of material from a starting workpart so the remaining part has the desired shape.
- Categories:
o Machining V material removal by a sharp cutting tool, e.g., turning, milling, drilling
o Abrasive processes V material removed by hard, abrasive particles, e.g., grinding
o Nontraditional processes V various energy forms other than sharp cutting tool to remove material
Machining*
- Cutting action involves a shear deformation of work material to form a chip
- As chip is removed a new surface is exposed
Why Machining is important
- Variety of work materials can be machined
o Most frequently applied to metals
- Variety of part shapes and special geometry features possible, such as:
o Screw threads
o Accurate round holes
o Very straight edges and surfaces
- Good dimensional accuracy and surface finish
Disadvantages with Machining
- Wasteful of material
o Chips generated in machining are wasted material, at least in the unit operation.
- Time consuming
o A machining operation generally takes more time to shape a given part than alternative shaping processes, such as casting, powder metallurgy, or forming.
Machining in the Manufacturing Sequence
- Generally performed after other manufacturing processes, such as casting, forging, and bar drawing
o Other processes create the general shape of the starting workpart
o Machining provides the final shape, dimensions, finish, and special geometric details that other processes cannot create.
Machining Operations
- Most important machining operations:
o Turning
o Drilling
o Milling
- Other machining operations:
o Shaping and planning
o Broaching
o Sawing
Turning*
- Single point cutting tool removes material from a rotating workpeice to form a cylindrical shape.
Drilling*
- Used to create a round hole, usually by means of a rotating tool (drill bit) that has two cutting edges...