By Umberto F. Catignani, Orbital Plastics Consulting Inc.
Weighing in at 7 pounds and just shy of 900 pages, The Complete
Part Design Handbook, For Injection Molding of Thermoplastics,
written by Mr. E. Alfredo Campo, is the most complete and
comprehensive handbook on thermoplastic product design available on the market today. It is undoubtedly the new reference manual for plastic part design in the industry.Mr. Campo has masterfully compiled hundreds of pages of
reference material, equations, nomenclature, design guidelines
and material properties accompanied by ample detailed real world
design problems and sample calculations.
To capture this wealth of information, one would need many
books, catalogs and subject matter references. Mr. Campo has
painstakingly performed this task with this publication and done
so with his 35 plus years of hands-on experience in the injection
molding design arena.
This all-inclusive handbook has a total of twelve chapters. Chapter
1, Plastic Materials Selection Guide is 114 pages and rightfully
could stand on its own as a book in itself. Mr. Campo introduces
polymeric materials and discusses 35 families of thermoplastic
materials, 8 families of thermoplastic elastomers and 16 families of
thermosetting materials. For each resin family, the basic chemistry,
properties, processing characteristics, advantages, disadvantages
and limitations are discussed along with typical applications and
example end use product illustrations.
Chapter 2, Engineering Product Design shifts the spotlight to understanding the properties of materials and structural design
of thermoplastic components. Centroid, section area, moment of
inertia equations and beam deflection analysis methods. Structural
analysis of beams, columns, flat circular plates and torsion.
Viscoelasticity is first introduced along with creep and stress
relaxation phenomena.
Transitioning to the meat of this handbook, Chapters 3 – 7 discuss
structural design characteristics for thermoplastics. Chapter 3
focuses on product wall thicknesses, structural rib design, sharp
corners, bosses, threads, undercuts, integral life hinges, pin hinges,
encapsulation of inserts, types of metal inserts and anchorage. This
chapter points out many of the fundamental “Do’s and Don’ts” of
plastic part design which many product designers unfortunately
learn from attending the “part design school of hard knocks.”
Chapter 4, entitled Thermoplastic Gearing Design discusses the
material property requirements for thermoplastic molded spur
gears, mounting gears on metal shafts, tolerances and overall
shrinkage of gears. Plastic spur and helical gearing technology
design, strength, horsepower ratings, equations, tables, analysis
examples and gear specification illustrations are abundantly
displayed in this chapter.
Chapter 5 is the complete guide to Plastic Journal Bearing Design.
Design principles, factors affecting performance and dimensions
along with clearances, molding effects, PV limits and surface
finishing. Equations, tables, and analysis examples are put forward.
Chapter 6, is the complete guide to Thermoplastic Spring Design.
Locating, fixing clip, flexible hinges and torsional spring applications
are reviewed. Belleville spring washers’ equations, tables and
analysis examples are included.
Chapter 8, Thermoplastic Assembly Methods, introduces the joining
of two or more components. Each assembly method provides a
description, process sequence, advantages and limitations, typical
applications, equipment, product joint design and its variations.
Joining methods include cold heading, electro fusion fitting, hot
plate welding, solvent and adhesive bonding, metal fasteners,
press and snap fits, electromagnetic, vibration, spin and ultrasonic
welding methods.
Chapter 9, Thermoplastic Effects on Design discusses basic melt
behavior, degradation, moisture effects, shrinkage and other critical
properties. The molding process is related to its overall effects on
product design dimensions and mechanical properties.
Chapter 10, Injection Mold Design is an incredible 176 pages and
thoroughly discusses everything a product designer needs to know
about mold design. Types of steels, surface finishing, classification,
hot and cold runner technology and design, cavitation, gating,
venting, ejection, cooling, sidewall strength, designer check list and
specifications for mold construction methods.
Chapter 11, Performance Testing of Thermoplastics introduces and
discusses over 45 ASTM and UL test methods, procedures and the
overall significance of the test.
As if that were not enough, Mr. Campo’s final chapter puts forward
three analysis methods to estimate the cost to manufacture molded
product along with the cost of capital equipment.
Whether you are a seasoned product designer or have a limited
knowledge of polymers and/or polymeric behavior, you will
undoubtedly find that this publication is an invaluable and
indispensable reference manual. It also offers guidelines for
specifying resins, machine selection and fundamental processing
parameters.
This handbook is not only a must have for the plastic product
designer but many toolmakers and processors will find this a
welcome addition to their reference manuals on injection molding.
