Book Review: Manufacturing of Polymer Composites
When designing a structure, you must take the manufacturing method into account. This is especially critical for composites because you manufacture the material at the same time you manufacture the part.
Anyone who works in the composites industry, therefore, needs to have a good understanding of the different manufacturing processes. Each process has different advantages and limitations, and may be limited to specific types of structures.
It is not so important to have a thorough knowledge of all processes--learning a single process can take years of experience. Rather, it is important know the basics of each process so you know where to start and what questions to ask.
Manufacturing of Polymer Composites by B.T. Åström provides that overview. Dr. Åström describes just about every processing technique in use. After reading this book, you should be able to select an appropriate manufacturing method for your composite structures, though you will still have to consult the shop foreman on implementing your design.
As with most books of this type, the first chapter is an introduction to composites. The focus is on applications, and examples are shown in every industry from aerospace to marine to consumer. A market analysis shows that most composites are used in high volume applications, and this fact isn't forgotten in the rest of the book.
An understanding of processing methods requires an understanding of material properties, especially in their uncured form, and constituent properties are covered in the second chapter. Both fibers and matrices are covered, but I found the matrix section to be particularly good.
The discussion starts with a general coverage of polymer chemistry. The size and shape of the polymer molecules are related to the properties of the crosslinked plastic. With these basic concepts in mind, the properties of specific matrix polymers are then discussed. The interaction of all of these basic factors becomes especially clear in the description of polyester systems.
Next comes a listing of quantitative material properties. Although the information is fairly standard, it is interesting to see how polymer structure (such as degree of crosslinkning) affects the composite properties.
The heart of the book is found in the fourth chapter, which covers manufacturing processes. Dr. Åström manages to hit on just about every technique currently in use--the only significant omission I noticed was e-beam curing.
The chapter starts with a section on issues common to all or most processes. This mainly means mold design and fabrication, but also includes material conformability and heat transfer.
Two large sections cover thermoset and thermoplastic layup techniques. Coverage of each method follows a standard format: process description; raw materials and molds; crosslinking; technique and component characteristics; and applications. Schematics and pictures of actual layups in progress make the concepts clear.
The technique and component characteristics are presented as a tabular summary (e.g. equipment cost: low; mold cost: low; etc.). This provides a simple method to quickly compare different processes (even though the tables are on different pages).
It is evident throughout the book that the author is used to dealing with real composite structures. For example, the manufacturing chapter ends with a section on manufacturing-induced defects, including cosmetic problems.
The book concludes with three topics not normally covered in composite references: quality control; recycling; and health and safety. The QC chapter is good in its coverage of testing methods, but I would like to see more discussion on the development and implementation of QA plans.
Everyone who works with composites, whether in the lab or on the production floor, should read the health and safety chapter. Uncured composites are hazardous materials, and post-cure processing can generate hazardous byproducts. This chapter gives a good overview of the dangers while putting the relative hazards in perspective (yes raw materials are hazardous, but when handled correctly they are safe).
One of the features I liked best about the book was the end of chapter summaries. These can best be described as an executive summary of each chapter. Compiled into a pamphlet, they would make a good stand-alone publication.
Because the book is meant as an introduction or overview, details are often lacking. Each chapter, therefore, provides both a suggested reading list and a bibliography. I have actually read many of the suggested references, so I can safely say that in general they are good selections.
My only real complaint about the book is the extensive use of abbreviations. A list is provided at the front of the book, but I found myself referring to it too often for the less common acronyms. It would help (in future editions of the book) to include full terms in the text when an abbreviation hasn't been used in a while.
This book is a good selection for anyone in the composites industry. It should be required reading for people new to the field, especially those who only had analytical classes in college (I know it would have saved me many headaches when I first started working). It also makes a good reference for practicing engineers, either as a refresher of old knowledge or an introduction to new techniques.
More detailed contents, as well as a c.v. for Dr. Åström, are available online.
Details: Manufacturing of Polymer Composites, by
B.T. Åström, published by Chapman & Hall, 1997, ISBN
0-412-81960-0.
1. Introduction; 2. Constituent Materials; 3. Properties;
4. Manufacturing Techniques; 5. Secondary Processing; 6. Quality
Control and Characterization; 7. Recycling; 8. Health and Safety