Generative process

P. Zatta, R. Lucchini, S. J. van Rensburg, A. Taylor, The role of metals in neurode-generative processes aluminum, manganese and zinc, Brain Res. Bull., 62 (2003), 15-28. 

A generative process-planning system consists of the following importemt functions ... 

The generative process-planning approach has the following advantages ... 

Part-Description Methods for Generative Process-Planning Systems... 

Some of the representations used in a generative process-planning system include GT code, line drawing, special language, symbolic representation, solid model, CSG, B-Rep, feature-based model. Extract and decompose features from a geometric model. 

Unlike other subtractive machining processes, Generative Processes buUd parts by a layer-by-layer technique using form neutral substances like fluids, powders, foil-or wire-shaped materials by chemical and or physical reactions. In general the process, as shown in Fig. 79, results directly from a 3D model, which is sliced into thin cross-sections typically with a thickness of 0.1-0.4 mm. Depending on the kind of process, parts that may be difficult or even impossible to fabricate by conventional methods, can be produced out of polymers, metal, ceramic or composite materials [101]. A selection of RP-processes is described below, but due to the complexity of the processes readers are referred to the cited references. 

A complete data-generative process for MALDI-MS can be captured in a Bayesian framework [38, 39]. The preprocessing phase is then a Bayesian inference procedure where the Nx P table of interest is the mean of a posterior distribution given the observed signals. The computation involved in simulation of the posterior distribution is expensive, however, and dedicated modeling expertise is required for this approach. 

Laser-based generative processes such as stereolithography and selective laser sintering are part of a group of techniques commonly known as layered manufacturing . These are rapid prototyping techniques that build up a 3D object (or physical model) layer by layer. They are used in fields like mechanical engineering, and more recently in medicine and health care, as they are fast and cost effective techniques for the manufacture of 3D parts. 

A comparison of the characteristics of generative and non-generative processes is helpful to understand the possibilities and limitations of generative manufacturing processes. This discussion is postponed to the end of the section (Section 4.7.6) because the principles of generative manufacturing must first be known. 

Generative processes are also used to produce cores and molds for sand casting, lost models, molds for investment casting, and master models for a variety of molding processes, preferably in soft (silicone) molds. Molds for sand and investment castings are not discussed in the context of this book, molding techniques are discussed in Section 1.11. 

D CAD Mold Rapid Fronted Generative Process-Specific... 

FIGURE 4.131 Geometric freedom of generative processes using the example of a structure with internal cavities (source Trumpf)... 

Rapid tooling means an application-oriented subset of the generative processes. 

The implementation of the generative principle as seen in Figure 4.129 lists five process families. The generative processes are associated in Table 4.7, which underlie the generative machinery, are available today. 

TABLE 4.7 The Five Generative Process Families and the Derived Generative Manufacturing Processes... 

FIGURE 4.143 Mold inserts, manufactured with different generative processes (partially cut)... 

Examples for the application of generative processes in the repair and maintenance, the texturing (Figure 4.147), which is applied with the powder nozzle, and the construction of a mold insert made from 1.2343 on a prefabricated blank, are made from the same material. 

Figure 4.148 shows a component made with the generative process and as a finish-machined insert. Generative processes have made their way into the production of... 

Non-generative processes work with materials in the form of semifinished parts, which are selected to match the mechanical properties of the product product-oriented material selection. 

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