Net shape processes

Sand Casting. Sand casting is the most popular method of molding for cast copper alloys. It is the least expensive near net shape process, and pattern costs are low. Dimensional tolerance capabiUties vary widely and are the least accurate when compared with other methods of casting. 

Another important feature of the net shape technology is that it does not follow percolation theory. This gives an opportunity to design materials with unique properties. As an example Ni-ceria cermet with low Ni content was prepared and investigated [16]. The net shape processed Ni-ceria cermet, which was prepared according to procedure presented in Figure 3-13, features ... 

Near-Net-Shape Processes Parts Examples of Applications 575... 

Special Applications NEAR-NET-SHAPE MANUFACTURING EXAMPLES 568 3.6.1. Thixoforging 3.6.2. Near-Net-Shape Processes for 584... 

Figure 2 Preconditions for Developing Near-Net-Shape Processes.

Modified knee presses up to a nominal force of 6300 kN are employed to extrude the valve tappets. The output capacity is 25-40 parts per minute. As a result of the near-net-shape process, the material is utilized to a higher extent—about 80%. The sizes of slot width and hole diameter are delivered at an accuracy ready for installation, whereas the outer diameter is pressed at IT quality 9-10 ready for grinding. The number of process steps and part manufacturing time were reduced. 

Near-net-shape processes for prototyping and smaU-batch production by means of rapid prototyping techniques can be characterised by the process chains listed in Figure 28. 

Figure 28 Near-Net-Shape Process Chain for Producing Prototypes and Small Series by Means of Generic Manufacturing Techniques (RP techniques).

The process is very nearly a true net-shape process - with little trimming required after process completion. 

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