[attachment=9966]
Manufacturing Processes: Classification & Selection & Fundamentals of Casting Process
Manufacturing Processes : Classification
1. Metal Casting Processes
2. Metal Forming Processes/Metal Working Processes
3. Fabrication Processes
4. Material Removal Processes
5. Powder Metallurgy
6. Special Processes
7. Non-traditional Processes
Brief of the Main Processes
Metal Casting Processes
• Alloy Making & Melting
• Mould Making
• Pouring
• Cooling & Solidification
• Removal of Runners & Risers
• Heat Treatment
• Subsequent Machining Operations, if Necessary
Metal Working Processes
• Selection of Process: Cold Working or Hot Working
• Cutting of required size of raw material
• Provision of a die, a punch and other arrangements (e.g. press for forging)
• Heating of the material if required above the re-crystallization temperature
• Carrying out forging operation, i.e. forcing the punch into the work piece kept in the die
• Cutting extra material, if necessary
• Subsequent machining operations, if necessary.
Fabrication Processes
(Product manufactured by joining different components by bolding, riveting, welding or other means)
1. Cutting the raw material into required sizes and/or making some pieces by machining casting and other processes.
2. Positioning the pieces in required configuration joining them through welding with series of inspections during joining
3. Cleaning, filing and other subsequent operations, if necessary.
Advantages & Disadvantages of the Processes
Casting processes
Advantages
1. Intricate shapes can be cast
2. Products of very large size can be made
3. Economical if large number of similar products are required to be made
4. As compared to forging the products made are lighter as exact radii, contours, bosses, collars, ribs, etc. can be made
Casting Processes
Disadvantages
1. A great deal of material wastage in the form of runners and risers.
2. Strength of the material is less as compared to forging particularly if direction of loading is to be considered
3. Many defects caused even with a small mistake. Some of these defects are internal and can be found only by destructive testing or advanced means
4. Not economical for small volumes of products in general
5. Some materials are not very conducive to casting
Metal working processes
Advantages
1. Economical if very large volumes of products are to be made
2. Grain direction and arrangement can be manipulated for achieving higher strengths in the direction of loading
3. Less material as compared to casting
4. Finish products can be made which do not require any further machining
Disadvantages
1. Generally heavier products as compared to casting as lugs, collars, ribs cannot be provided
2. Very intricate shapes cannot be produced as compared to casting
3. Some materials are not conducive to metal working processes.