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1 Introduction
Rapid prototyping (RP) is an automatic process of manufacturing objects directly from their CAD models without the use of any tooling specific to the geometry of the objects being produced. RP adopts a divide-and-conquer approach in which the complex 3D object is split into several 2D slices that are simple to manufacture. Furthermore, as the object grows from bottom up, the chances of collisions are eliminated.
RP revolutionized the way products are designed and manufactured today. Its ability to realize conformal cooling channels and gradient objects are its most significant advantages. Figure 1(a) [Figure omitted. See Article Image.] shows an example of incorporating conformal cooling channels in a mold. Figure 1(b) and (c) [Figure omitted. See Article Image.] are examples of gradient matrix for non-metals and the same for metals are shown in Figure 1(d) and (e) [Figure omitted. See Article Image.] ([8] Karunakaran et al. , 2006).
2 Rapid manufacturing
RP cuts down product development time and rapid tooling (RT) cuts down productionizing time. Therefore, rapid prototyping & tooling (RP&T) is an effective tool where time to market matters. However, use of RP is still limited to the manufacture of only prototypes, mostly of non-metallic materials. The dream of manufacturing engineers today is to extend the total automation to functional and full-life components. In other words, RP is evolving into rapid manufacturing (RM). The following bottlenecks are the hindrance to this evolution:
- poor quality;
- short life;
- long cycle time; and
- high cost.
Slicing that contributed to RP's total automation is also responsible for these problems. Today's rapid prototypes leave much to be desired in terms of the quality of geometry (accuracy and surface finish) and material (strength, variety, homogeneity, size, proprietary nature, etc.). One can produce parts out of any material on a CNC machine by using appropriate cutting parameters. On the other hand, if a new material is to be used on a RP machine, elaborate experimentation is required to fine-tune the process for the new material. Due to layered manufacturing, all RP processes inherently exhibit anisotropy. Furthermore, due to enormous quantity of heat generated, metallic RM methods are prone to distortion and cracking defects, leading to poor accuracy and strength. Due to these quality restrictions,...