Preface

Plastic products are indispensable in our everyday life. Today, the injection molding is the most used method for producing plastics parts. Using injection molding process, the plastic materials can be melted or remelted and injected at high pressure into the mold cavity to produce parts with desired shape.

I started my study on injection molding seven years ago. When I was an undergraduate student, I got acquainted with mechanics and control. Then, injection molding opened a new and interesting world for me to know mechanical engineering and plastic materials. To research in this direction, I got the opportunity to do a PhD study at Beijing University of Chemical Engineering. In the first of my PhD study, ARBURG, a famous global manufacturers of injection molding machines, supported a machine to my laboratory. It became the first injection molding machine which I used. Then, I used different kind of injection molding machines from LK Machinery, Haitian, GSK, etc. The basic of my research is from the PVT (Pressure-Volume-Temperature) properties of polymers which are important for both engineering and polymer physics. According to the polymer PVT properties, mold design, numerical simulation and process control for injection molding could become easily to realize. The on-line PVT measurement and one application example presented in one chapter of this book had been presented in my two articles.

After graduation, I became a teacher in Beijing Institute of Technology, and I am still doing research on polymer engineering. Fields of my interest include injection molding and innovative plastics manufacturing processes, micro-injection molding, design and process optimization, computer-aided engineering (CAE) and numerical simulation, properties for plastics. I am still working hard on these fields and hoping more research achievements will benefit to our life and society.

This book is composed of different chapters which are mainly related to the subject of injection molding. All the contents not only contain the fundamental knowledge but also have many new research results and techniques by the authors, some leading international academic experts in the field. I define the book title as "Some Critical Issues for Injection Molding" in the context of the research field covered.

#### X Preface

Chapter 1 of this book contains introduction on polymer PVT measurements and two main application areas of polymer PVT data in injection molding including numerical simulation and process control. The knowledge on PVT properties of polymers could be the fundamental concepts for the engineers in injection molding. Chapter 2 presents the effective run-in and optimization of an injection molding process guiding readers how to install robust processes or how to review and optimize them. Chapter 3 to 7 are mainly on powder injection molding which was invented and developed in the early 1970s and comprises ceramic injection molding and metal injection molding. Powder injection molding has been accepted as one of the fundamental manufacturing techniques in recent years, and it is leading the way to new prospective market segments. Chapter 8 is about microcellular injection molding which was originally concetualized and invented at the Massachusetts Institute of Technology in 1984. Microcellular technology has already had a significant impact on the worldwide plastics industry. The insert molding process employing vapour chamber is introduced in Chapter 9. Insert molding process is a simplified injection molding method that eliminates secondary processing and assembly. Chapter 10 focused on the natural fiber-thermoplastic composites, reviewed some influence factors on the injection molding process to produce natural fibers thermoplastic compound, and introduced some research on interfacial strength of injection molded composites. Chapter 11 explored and analyzed the properties of injection molded high density polyethylene nanocomposites filled with exfoliated graphene nanoplatelets.

It is now a great pleasure for me to complete one chapter and the review of the other chapters in this book. Finally, I am grateful to all the authors and the support of different foundations or companies for their research. I very much hope that the contents presented here will provide some clear presentation of injection molding process and equipment to direct people in plastics manufacturing to solve problems and avoid costly errors. With useful, fundamental information for knowing and optimizing the injection molding operation, I also hope the readers could gain some working knowledge of the injection molding.

> **Jian Wang**  School of Chemical Engineering and Environment, Beijing Institute of Technology China

X Preface

Chapter 1 of this book contains introduction on polymer PVT measurements and two main application areas of polymer PVT data in injection molding including numerical simulation and process control. The knowledge on PVT properties of polymers could be the fundamental concepts for the engineers in injection molding. Chapter 2 presents the effective run-in and optimization of an injection molding process guiding readers how to install robust processes or how to review and optimize them. Chapter 3 to 7 are mainly on powder injection molding which was invented and developed in the early 1970s and comprises ceramic injection molding and metal injection molding. Powder injection molding has been accepted as one of the fundamental manufacturing techniques in recent years, and it is leading the way to new prospective market segments. Chapter 8 is about microcellular injection molding which was originally concetualized and invented at the Massachusetts Institute of Technology in 1984. Microcellular technology has already had a significant impact on the worldwide plastics industry. The insert molding process employing vapour chamber is introduced in Chapter 9. Insert molding process is a simplified injection molding method that eliminates secondary processing and assembly. Chapter 10 focused on the natural fiber-thermoplastic composites, reviewed some influence factors on the injection molding process to produce natural fibers thermoplastic compound, and introduced some research on interfacial strength of injection molded composites. Chapter 11 explored and analyzed the properties of injection molded high density

polyethylene nanocomposites filled with exfoliated graphene nanoplatelets.

working knowledge of the injection molding.

It is now a great pleasure for me to complete one chapter and the review of the other chapters in this book. Finally, I am grateful to all the authors and the support of different foundations or companies for their research. I very much hope that the contents presented here will provide some clear presentation of injection molding process and equipment to direct people in plastics manufacturing to solve problems and avoid costly errors. With useful, fundamental information for knowing and optimizing the injection molding operation, I also hope the readers could gain some

**Jian Wang**

China

School of Chemical Engineering and Environment,

Beijing Institute of Technology

**Part 1**

**Basics for Injection Molding**