Page 571 - 04. Subyek Engineering Materials - Manufacturing, Engineering and Technology SI 6th Edition - Serope Kalpakjian, Stephen Schmid (2009)

Synthesis, Design, and Projects 55|

SYNTHESIS, DESIGN, AND PROIECTS

20.24. Rapid-prototyping machines represent a large capi- 20.27. Identify the rapid-prototyping processes described in
tal investment; consequently, few companies can justify the this chapter that can be performed with materials available in
purchase of their own system. Thus, service companies that your home or that you can purchase easily at low cost.
produce parts based on their customers’ drawings have be- Explain how you would go about it. Consider materials such
come common. Conduct an informal survey of such service as thin plywood, thick paper, glue, and butter, as well as the
companies, identify the classes of rapid-prototyping machines use of various tools and energy sources.
that they use, and determine the percentage use of each class. 20.28. Design a machine that uses rapid-prototyping tech-
20.25. Qne of the major advantages of stereolithography is nologies to produce ice sculptures. Describe its basic features,
that it can use semitransparent polymers, so that internal de- commenting on the effect of size and shape complexity on
tails of parts can readily be discerned. List and describe sever- your design.
al parts in which this feature is valuable. 20.29. Because of relief of residual stresses during curing,
20.26. A manufacturing technique is being proposed that long unsupported overhangs in parts made by stereolithogra-
uses a variation of fused-deposition modeling in which there phy tend to curl. Suggest methods of controlling or eliminat-
are two polymer filaments that are melted and mixed prior to ing this problem.
being extruded to make the part. What advantages does this
method have?