Document Text Contents
Page 27
Manufacturing Processes for Engineering Materials, 5th ed.
Kalpakjian • Schmid
© 2008, Pearson Education
Mold Features
FIGURE 10.28 Illustration of mold features for injection molding. (a) Two-plate mold, with
important features identified; (b) injection molding of four parts, showing details and the volume
of material involved. Source: Courtesy of Tooling Molds West, Inc.
(b)
Main
runner
Gate
Cavity Guide
pin
Guide pinSprue
Cavity
Branch
runner
(a)
Gate
Sprue
Part
Main
runner
Cold slug well
Branch
runner
Page 54
Manufacturing Processes for Engineering Materials, 5th ed.
Kalpakjian • Schmid
© 2008, Pearson Education
Design of Polymer Parts
(b) (c) (d)
Extruded product
Die shape
Original
design
Distortion Modified
design
(a)
Thick
Pull-in (sink mark)
Thin
FIGURE 10.57 Examples of design modifications to eliminate or
minimize distortion of plastic parts. (a) Suggested design changes
to minimize distortion. Source: After F. Strasser. (b) Die design
(exaggerated) for extrusion of square sections. Without this
design modification, product cross-sections would not have the
desired shape because of the recovery of the material, known as
die swell. (c) Design change in a rib to minimize pull-in caused
by shrinkage during cooling. (d) Stiffening of the bottom of thin
plastic containers by doming, similar to the process used to
make the bottoms of aluminum beverage cans and similar
containers.
Manufacturing Processes for Engineering Materials, 5th ed.
Kalpakjian • Schmid
© 2008, Pearson Education
Mold Features
FIGURE 10.28 Illustration of mold features for injection molding. (a) Two-plate mold, with
important features identified; (b) injection molding of four parts, showing details and the volume
of material involved. Source: Courtesy of Tooling Molds West, Inc.
(b)
Main
runner
Gate
Cavity Guide
pin
Guide pinSprue
Cavity
Branch
runner
(a)
Gate
Sprue
Part
Main
runner
Cold slug well
Branch
runner
Page 54
Manufacturing Processes for Engineering Materials, 5th ed.
Kalpakjian • Schmid
© 2008, Pearson Education
Design of Polymer Parts
(b) (c) (d)
Extruded product
Die shape
Original
design
Distortion Modified
design
(a)
Thick
Pull-in (sink mark)
Thin
FIGURE 10.57 Examples of design modifications to eliminate or
minimize distortion of plastic parts. (a) Suggested design changes
to minimize distortion. Source: After F. Strasser. (b) Die design
(exaggerated) for extrusion of square sections. Without this
design modification, product cross-sections would not have the
desired shape because of the recovery of the material, known as
die swell. (c) Design change in a rib to minimize pull-in caused
by shrinkage during cooling. (d) Stiffening of the bottom of thin
plastic containers by doming, similar to the process used to
make the bottoms of aluminum beverage cans and similar
containers.
