Rapid Prototyping in Manufacturing
Rapid prototyping (RP) is the name applied to a group of novel part-manufacturing processes relying on the rapid solidification of a loose material. They are supposed to be faster and more flexible than conventional forming techniques and therefore partic
- PDF / 539,130 Bytes
- 13 Pages / 439 x 666 pts Page_size
- 23 Downloads / 231 Views
Rapid prototyping (RP) is the name applied to a group of novel part-manufacturing processes relying on the rapid solidification of a loose material. They are supposed to be faster and more flexible than conventional forming techniques and therefore particularly suited to producing prototypes in a very short time.
12.1 The Idea Classical manufacturing of solid parts relies on one of the following three principles (Fig. 12.1): 1. Take a solid blank of the chosen material that is bigger than the desired object, so that the final piece is fully contained within the bounding surface of the blank. Create the piece by removing all surplus material, leaving just the piece you want. 2. Prepare a form (die or mold) that is the exact negative of the desired object (apart from details such as filling holes and shrinking allowance). Fill it with the chosen material, which has to be in an easily deformable state – liquid, soft plastic, or powder – and let it solidify. Remove the form to obtain access to the finished solid part.
Fig. 12.1 The classical principles of part manufacturing: a) Remove excess material from solid blank; b) Have liquid or powdery material solidify in a mould; c) Change shape of fixed mass of plastic material: c1) Solid block; c2) Sheet or plate.
A. Dashchenko (ed.), Manufacturing Technologies for Machines of the Future © Springer-Verlag Berlin Heidelberg 2003
368
F.H. Rehsteiner
3. Take exactly the right amount of the chosen material in a hard-plastic state, i.e., one able to withstand the force of gravity and reasonably careful handling. Knead it into the desired shape, then let it solidify (e.g., by cooling or baking). All of these processes suffer from one or more of the following drawbacks: (1) demanding work and tool preparation; (2) requiring sophisticated machining programs and fixtures; (3) requiring expensive tools such as molds, dies, and accurate cutting tools; (4) all of the tools are subject to wear and hence need to be replaced periodically; (5) excess material is wasted when applying principles 1 and 2; and (6) expensive machinery is required, mostly with a narrow range of application (e.g., machine tool, melting/baking oven, or forging press). These attributes imply that classical manufacturing technologies are rather inflexible; a typical time delay for producing a demanding prototype, e.g., the crankshaft housing of a car engine, is of the order of 10 weeks. This is especially incompatible with the requirements of today’s market, where the saying “time is money” holds true more than ever before. Therefore, towards the end of the 1980s, investigations started in an alternative manufacturing principle: take an easily deformable – liquid or powder – substance and solidify it just where you need it and nowhere else. After having created (solidified) the whole piece, remove the excess material which is still fully deformable, and reuse this excess material whenever possible. Soon two additional principles proved to be highly important: have the amount of material solidified at a time s
Data Loading...
