Material selection manufacturing process

Farag, M. M., Selection of Materials and Manufacturing Processes for Engineering Design, Prentice-Hall, Englewood Cliffs, NJ, 1989. 

The criteria for process design for clean manufacturing focus on minimizing pollution, eneigy consumption, water consumption, secondary processes, or redundant processes. Table 5 provides a summary of suggested guidelines for materials selection and process design. 

Membrane manufacturers frequently have as much technology and art invested in the selection and processing of the tubesheet and sealants as in the membrane itself. Understandably, much of the details about tubesheet and gasket material selection and processing is considered proprietary and trade, or closely guarded, secret information by membrane manufacturers. 

It is well known that the mechanical properties of fiber-reinforced polymer composites are generally governed by three factors (i) the mechanical properties of the reinforcing elements, (ii) the size, shape and orientation of the reinforcement, and (iii) the quality of the interfacial adhesion existing between the constituents. All of these factors are addressed during the selection of the MFC materials and manufacturing process. 

The constraints on design imposed by the processes for manufacture have been covered in this chapter for a number of the widely used plastics manufacturing processes. The first step in product design should be the selection of the material and manufacturing process. Not all processes were covered, just those that are most frequently met in design practice. The basic process limitations were discussed... 

The creation of a plastic part requires a series of conscious decisions regarding type of plastic, method of production, design of mold or tooling, and selection of machine or process. Reaching these decisions requires information as to the intended usage of the part and the conditions of environment (temperature, moisture, exposure to harsh atmospheres, physical and electrical requirements). Furthermore, in most cases, the cost to manufacture the part is a major consideration and is dependent on the choice of materials, the manufacturing process, and, of course, the quantities to be produced per shift, month, or year. 

P. P. Dargie, K. Parmeshwar, and W. R. D. Wilson, MAPS 1 Computer-aided design system for preliminary materials and manufacturing process selection, Trans. ASME,. Mech. Design, 104 126-136,1982. 

Time-dependent failure probability results can also be used to develop design curves for the selection of constiment materials and manufacturing processes for a maximum-allowable failure probability criteria and desired service life as shown in Figures 5.6 and 5.7. For instance, in order to maintain a failure probability less than 3% (or reliability of 97%) for 10 years, a CFRP-composite rehabilitation needs to attain Vf= 31.5% at the time of constmction, using materials described in this analysis. 

Petroleum asphalts, compared to native asphalts, are organic with only trace amounts of inorganic materials. They derive their characteristics from the nature of their cmde origins with some variation possible by choice of manufacturing process. Although there are a number of refineries or refinery units whose prime function is to produce asphalt, petroleum asphalt is primarily a product of integrated refineries (Fig. 1). Cmdes may be selected for these refineries for a variety of other product requirements and the asphalt (or residuum) produced may vary somewhat in characteristics from one refinery-cmde system to another and even by cut-point (Table 2) and asphalt content (Fig. 2) (5,6). The approximate asphalt yields (%) from various cmde oils are as follows ... 

Processing is key to the reproducible manufacture of ceramics. The tolerance of a finished ceramic to defects determines the raw materials selected, and the control that must be exercised during processing. More expensive advanced ceramics require higher quaUty, more expensive raw materials coupled with more carefully controlled manufacturing processes. 

Activated carbon is an amorphous solid with a large internal surface area/pore strucmre that adsorbs molecules from both the liquid and gas phase [11]. It has been manufactured from a number of raw materials mcluding wood, coconut shell, and coal [11,12]. Specific processes have been developed to produce activated carbon in powdered, granular, and specially shaped (pellet) forms. The key to development of activated carbon products has been the selection of the manufacturing process, raw material, and an understanding of the basic adsorption process to tailor the product to a specific adsorption application. 

A compromise among properties, cost, and manufacturing process generally determines the material of construction. Selecting a plastic is very similar to selecting a metal. Even within one class, plastics differ because of varying formulations, just as steel compositions vary (tool steel, stainless steel, etc.). There are, of course, products for which no plastics is satisfactory, and the interests of the producer and consumer alike are best served by using some other material. 

Volume 1 addresses the initial stages in solving a materials selection problem, provides the background to all aspects of materials behavior, and discusses manufacturing processes. 

Sources of data on costs were discussed in Chapter 6 and materials of construction in Chapter 7. This chapter covers sources of information on manufacturing processes and physical properties and the estimation of physical property data. Information on the types of equipment (unit operations) used in chemical process plants is given in Volume 2, and in the Chapters concerned with equipment selection and design in this Volume, Chapters 10, 11 and 12. 

Contents Introduction to Materials. Manufacturing Considerations for Injection Molded Parts. The Design Process and Material Selection. Structural Design Considerations. Prototyping and Experimental Stress Analysis. Assembly of Injection Molded Plastic Parts. Conversion Constants. 

---