Page 42 - Handbook of Plastics Technologies

INTRODUCTION TO POLYMERS AND PLASTICS

1.28 CHAPTER 1

FIGURE 1.23 Injection compression process. 63

FIGURE 1.24 Lost-core injection molding process. 64

then followed by the second material as depicted in Fig. 1.26. In this process, the first ma-
terial goes to the outside of the mold and forms the skin, and the second material forms the
interior of the part. This is often referred to as sandwich molding. Materials may be in-
jected either sequentially or simultaneously. Applications include the use of an expensive
outer layer and a cheaper core material or with fiber reinforced materials, where a skin ma-
terial is used for improved surface quality.

Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com)
Copyright © 2006 The McGraw-Hill Companies. All rights reserved.
Any use is subject to the Terms of Use as given at the website.