Milling can be defined as the process through which material is cut using rotating tooth cutters. The combination of many teeth operating around the milling cutter enhances the working of the process. In addition, the material being worked on can be cut into different shapes for instance, curved, flat or angular (Nowosielski & Babilas, 2007). The process is also able to produce a combination of shapes. The milling machine is, therefore, the combination of systems used to hold the surface into place, rotate the cutter, and feed surfaces. There are important factors that need to be considered when planning for a milling process. For good results, the means of holding the surfaces and the cutters being used should be appropriate. In addition, the cutting speed as well as the feed rate should be in balance. This can only be achieved by application of a number of factors. It is very vital that the type of material being machined and that of the cutting tool are considered (Nowosielski & Babilas, 2007). Check out for rigidity of the system and the physical ability of the cutter. The type of finish expected, and power at the spindle are the key factors in the system.
Transforming is an old method of processing plastic products. Applications of transformed plastic materials are quite versatile and ranges from simple packaging to materials used in areas of high impact such as cockpit covers. Simple forms of transforming are done by passing heated plastic over a mold vacuum. The mold is then left to cool and then ejected by the use of a reverse pressure (Nowosielski & Babilas, 2007). Vacuum transforming applies. Advanced vacuum transforming involves the use of hydraulic systems combined with heat and process controls that enhance vacuum forming for applications required for heavy duties. Vacuum transforming requires low forming pressures and is, therefore, cost-effective. The process, however, requires the use of plastic unlike other processes that start with resin base. Secondly, a piece of material has to be cut off from the finished product.
The process of centrifugal casting is used to produce small parts that form complex geometry. The horizontal centrifugal casting involves rotation of a mold in its horizontal axis and melt in the extreme centrifugal force is pushed against the wall of the mold. The melt forms the shell of the roll (Vaidyanathan, Schulman, Nielsen, & Shalita, 1981). Liquid metal is added from the center of the mold. The process of filling the mold takes about two minutes, and the rate of flow is around 30 kg/s. the liquid metal is supposed to adhere to mold and creates a ring on the circumference. The ring then expands to the mold extremities. The interaction of the forces the causes various wave patterns to form on the free surface. Centrifugal casting is efficient in the production of graduated composite products. The process is determined by the temperatures of the metal, solidification rate as well as thermal properties. It is crucial to understand the process of solidification.
Nowosielski, R and Babilas, R (2007) Fabrication of Bulk metallic glasses by centrifugal Casting Method. Journal of achievement in materials and manufacturing engineerin. Vol 20. Issue 1-2.
Vaidyanathan, A ,Schulman, J.P, Nielsen, S and Shalita. S (1981). Correlation between macro-scopic porosity location and liquid metal pressure in centrifugal casting technique.J Dent Res, vol 60, pp.59-66.