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This third edition has been written to thoroughly update the coverage of injection molding in the World of Plastics. There have been changes, including extensive additions, to over 50% of the content of the second edition. Many examples are provided of processing different plastics and relating the results to critiCal factors, which range from product design to meeting performance requirements to reducing costs to zero-defect targets. Changes have not been made that concern what is basic to injection molding. However, more basic information has been added concerning present and future developments, resulting in the book being more useful for a long time to come. Detailed explanations and interpretation of individual subjects (more than 1500) are provided, using a total of 914 figures and 209 tables. Throughout the book there is extensive information on problems and solutions as well as extensive cross­ referencing on its many different subjects. This book represents the ENCYCLOPEDIA on IM, as is evident from its extensive and detailed text that follows from its lengthy Table of CONTENTS and INDEX with over 5200 entries. The worldwide industry encompasses many hundreds of useful plastic-related computer programs. This book lists these programs (ranging from operational training to product design to molding to marketing) and explains them briefly, but no program or series of programs can provide the details obtained and the extent of information contained in this single sourcebook.

Inhaltsverzeichnis

Frontmatter

1. The Complete Injection Molding Process

Abstract
This chapter provides an introduction and overview of the injection molding machine (IMM) process. It provides text with pictorial reviews. Details on the important information pertaining to IMM and reviewed in this chapter are provided in the other chapters. Figure 1-1 provides an overview that basically summarizes what should be considered to ensure that the molded product meets performance requirements and provides a good return on investment to produce all types and shapes of products for all types of markets.
Dominick V. Rosato, Donald V. Rosato, Marlene G. Rosato

2. Injection Molding Machines

Abstract
The injection molding machine (IMM) is one of the most significant and rational forming methods existing for processing plastic materials. A major part in this development has been by the forward-thinking machinery industry, which has been quick to seize on innovations and incorporate them into plastic molded products. The most recent examples are the all-electric and hybrid IMMs. A major focus continues to be on finding more rational means of processing the endless new plastics that are developed and also produce more cost-efficient products. A simplified general layout for an IMM is shown in Figs. 2-1 and 1–3.
Dominick V. Rosato, Donald V. Rosato, Marlene G. Rosato

3. Plasticizing

Abstract
To mold plastic products, the plastic is plasticized, that is, it is melted. The plasticator is the device that does so. Different methods can be used. The common types are those found in the single-stage (or reciprocating) and the two-stage IMMs (Chap. 2). In the reciprocating type, plastic is fed through a screw and into a shot chamber (front of screw). In the two-stage plastic is fed into the first-stage screw, where it is plasticized prior to entering the second stage. In the first-stage plasticator the screw motion generates controllable low pressure [usually 50 to 300 psi (0.34 to 2.07 MPa)], which causes the screw to retract slightly, preparing the melt to enter the second stage. Depending on the plastic’s melt flow characteristics and pressure required in the mold cavity or cavities, the injection pressure at the nozzle is between 2,000 and 30,000 psi (14 and 200 MPa). Adequate clamping pressure must be used to keep the mold from opening (flashing) during and after the filling or packing of the cavities with the plasticized melt.
Dominick V. Rosato, Donald V. Rosato, Marlene G. Rosato

4. Molds to Products

Overview
In the manufacture of molded products there is always a challenge to utilize advanced techniques such as monitoring and control systems (Chap. 7), statistical analysis, and so on. However, these techniques are only helpful if the basic operations of molding are understood and characterized to ensure the elimination or significant reduction of potential problems. This understanding encompasses factors such as mold design and operation, plastic performance during melting (Table 4-1), and the operation of the injection molding machine (IMM) to produce costperformance-effective products at a profit (Chaps. 8 and 14).
Dominick V. Rosato, Donald V. Rosato, Marlene G. Rosato

5. Fundamentals of Designing Products

Overview
The term “design” has many connotations. Essentially it is the process of devising a product that fulfills as completely as possible the total requirements of the user, while satisfying the needs of the fabricator in terms of cost effectiveness (return on investment). Basically design is the mechanism whereby a requirement is converted to a meaningful plan such as summarized in Fig. 5-1.
Dominick V. Rosato, Donald V. Rosato, Marlene G. Rosato

6. Molding Materials

Overview
With a little effort practically any plastic injection molding machine is capable of producing melts to produce products. However, different interrelationships exist between materials and processing equipment operations so that if results are not properly analyzed and applied inferior products and usually more expensive products are produced. The many different plastics with their many different fabricating characteristics produce all kinds of products worldwide (Fig. 1–17). Total consumption of all plastics is summarized in Table 6–1. Of the total consumption about 32 wt% go through IMMs. Extruders process about 36 wt%. Even though injection molding comes in second plastic consumptionwise, in the United States alone about 80,000 injection molding machines are operating versus about 18,000 extruders.
Dominick V. Rosato, Donald V. Rosato, Marlene G. Rosato

7. Process Control

Abstract
Injection molding control involves many facets of both machine operation and the behavior of plastic, most importantly their interaction. Principally the processing pressure and temperature versus time determine the quality of the molded product. The design of the control system has to incorporate the logical sequence of all these basic functions, including injection speed (which is pressure dependent), clamping and opening the mold, opening and closing of actuating devices, barrel temperature profile, melt temperature, mold temperature, cavity pressure, holding pressure, and so on (Figs. 7-1 and 7-2). These controls are essential to produce molded quality products. Quality features include mechanical properties, dimensional accuracy, absence of distortion, and surface quality (Chap. 4).
Dominick V. Rosato, Donald V. Rosato, Marlene G. Rosato

8. Design Features That Influence Product Performance

Overview
Different techniques or methodologies are used to analyze premature molded product failures. Throughout this book the design problems (with solutions) that could cause failures are discussed. This chapter concentrates on this subject by providing more details. A variety of auditing methods and computer software programs are used or developed by molders to provide an analysis of potential problems. Although the actual time and cost to design a product may represent less than 5% of the total time and cost, the influence on the performance and cost of the final fabricated molded product is enormous.
Dominick V. Rosato, Donald V. Rosato, Marlene G. Rosato

9. Computer Operations

Overview
Computers permeate all areas of the plastics industry from the concept of a product design, to raw material processing, to marketing and sales, to recycling, and so on. Even more vital than the computers themselves are those who operate them. Computer operators, must be equipped with the proper knowledge of both hardware and software to make efficient use of these technologies.
Dominick V. Rosato, Donald V. Rosato, Marlene G. Rosato

10. Auxiliary Equipment and Secondary Operations

Abstract
There are many different types of auxiliary equipment (AE), also called secondary equipment. They support inline production systems and secondary operations (SO) used to maximize overall processing productivity and efficiency and/or reduce operating cost. Primary processing equipment in the line identifies the basic injection molding machine. The cost of the upstream and downstream AE can sometimes be more than that of the primary IMM. Different performance requirements for the AE exist so it is important to use the specific type required in the production line that proves most reliable. The proper selection, use, and maintenance of auxiliary equipment are as important as the selection of the primary IMM. Figures 10-1 and 10-2 show examples of injection molding lines that start upstream with materials being delivered. The material is delivered to the IMM and progresses through the downstream equipment where the finished product leaves the plant. A set of rules have been developed to help govern the communication protocol and transfer of data between primary and auxiliary equipment.
Dominick V. Rosato, Donald V. Rosato, Marlene G. Rosato

11. Troubleshooting and Maintenance

Abstract
Troubleshooting is the art and science of remedying defects after the process has demonstrated the ability to produce acceptable production parts. Most defects respond to one of a variety of process and/or material changes. The goal is to correctly identify which problem is actually causing the defect and to know when a particular solution will work. When making adjustments consider the following recipe: (1) create a mental image of what should be happening, (2) look for obvious differences, (3) make only one change at a time, and (4) allow the process to stabilize after any change is made. Studies have determined that about 60% of defects result from machines and equipment, 20% from molds and dies 10% from material, and 10% from operator error. Software programs, either already installed on the machine’s processor controller or available as a software package, can provide some help (157, 158, 255, 582).
Dominick V. Rosato, Donald V. Rosato, Marlene G. Rosato

12. Testing, Inspection, and Quality Control

Abstract
Testing refers to the determination by technical means of properties and performances. It yields basic information about plastic, its properties relative to another material, and its quality with reference to standards. Most of all, it is essential for determining the performance of plastic materials to be processed and of the finished products. When possible, testing should involve application of established scientific principles and procedures. It requires specifying what requirements are to be met. There are many different tests that can be conducted that relate to practically any requirement. Many different tests are provided and explained in different specifications and standards. These tests fall into two categories: destructive and nondestructive.
Dominick V. Rosato, Donald V. Rosato, Marlene G. Rosato

13. Statistical Process Control and Quality Control

Overview
Statistics is a branch of mathematics dealing with the collection, analysis, interpretation, and presentation of masses of numerical data. The word statistics has two generally accepted meanings: (1) a collection of quantitative analysis data (data collection) pertaining to any subject or group, especially when the data are systematically gathered and collated, and (2) the science that deals with the collection, tabulation, analysis, interpretation, and presentation of quantitative data.
Dominick V. Rosato, Donald V. Rosato, Marlene G. Rosato

14. Costing, Economics, and Management

Overview
The cost to produce a product involves many different categories: materials and hardware, method of purchasing, processing method, additives used, and manufacturing costs (Fig. 14-1). It is a misconception that plastics are “cheap,” for although there are low cost types there are also more specialized and expensive types. However, a major cost advantage for injection-molded products is the low processing cost.
Dominick V. Rosato, Donald V. Rosato, Marlene G. Rosato

15. Specialized Injection Molding Processes

Abstract
The versatility of the injection molding process has spawned a whole new generation of machines to fabricate special marketable products. Since 1872 when the first US injection molding machine patent was issued, a variety of specialized machines have been placed in service. They all Utilize the basic IMM principle of melting a plastic and forcing the melt into a cavity to produce a molded product. Many specialized IMM are actually well-documented machines and are extensively used for such applications as injection blow molding (1, 3, 4, 13, 14, 18, 54, 318).
Dominick V. Rosato, Donald V. Rosato, Marlene G. Rosato

16. Injection Molding Competition

Abstract
Competition will always exist among processes and among materials as they vie for their share of the worldwide market. For over a century plastics have successfully competed with other materials (steel, aluminum, wood, etc.) in both old and new applications, providing cost and performance advantages. In fact within the plastics industry itself different plastics compete against each other. There are many examples, including thermoplastic elastomers versus thermoset rubbers and clear film LLDPE versus LDPE and PVC. This competition will continue and expand as is evident by the new plastics being developed. New material developments have been made with, for example, the metallocene catalyst systems (Chap. 6) of DuPont. This iron and cobalt single-site catalyst system can make HDPE with higher melting points while incorporating adhesion and enhanced barrier performance as well.
Dominick V. Rosato, Donald V. Rosato, Marlene G. Rosato

17. Summary

Abstract
Injection molding is a major worldwide business. As Fig. 17-1 summarizes there is an interrelationship among all plastic processing methods, all the molded products, and applications in all types of industry.
Dominick V. Rosato, Donald V. Rosato, Marlene G. Rosato

Backmatter

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