Designing Plastic Parts for the Injection Molding Process

Get a fundamental overview of plastic part design for the process of injection molding – ideal for engineers and designers who are accustomed to working with metals, but faced with metal-to-plastic concerns. Examine plastic materials, behavior and selection, engineering design, manufacturing considerations and assembly methods.

This course can be applied to the Plastics Technology Certificate.


Robert Malloy

Robert Malloy

Robert Malloy is an Emeritus Professor at the University of Massachusetts-Lowell in the Plastics Engineering Department and has been a faculty member at UMass-Lowell since 1987. Prior to joining the faculty at Lowell, he was a faculty member at the ... read more

Who Should Attend

Engineers and designers who are accustomed to working with metals and are faced with metal to plastic concerns.

Benefits and Learning Outcomes

  • Learn how to select an appropriate plastic material formulation
  • Discover how to work within the manufacturing limitations associated with the injection molding process
  • Understand how to approach plastic product development and establish end use requirements

Course Outline/Topics

An Introduction to Plastic Materials

  • Historical Development
  • Fundamental Concepts
  • Molecular Weight
  • Repeat Unit Structure
  • Morphology
  • Effect of Additives
  • Mechanical Property Overview
  • Flow Property Overview
  • Advantages of Plastic Materials
  • Limitations of Plastic Materials

Review of Injection Molding Equipment

Review of the Injection Molding Process

Review of Injection Molds

  • Design Considerations for Injection Molded Parts
  • Mold Filling Considerations
  • Effect of Gate Location and Type
  • Molecular and Fiber Orientation
  • Mold Filling Pressure Drop
  • Flow Leaders and Flow Hesitation
  • Mold Filling Simulations
  • Runner Balancing and Family Molds
  • Weld or Knit Lines
  • Shrinkage and Warpage Considerations
  • Part Ejection Considerations

Mechanical Behavior of Plastic Materials

Approaching Plastic Product Development

  • Establishing End Use Requirements
  • Conceptual Design
  • Initial Candidate Material Selection Procedures
  • Design Based Upon the Materials Selected
  • Final Materials Selection
  • Manufacturing Related Design Modifications
  • Prototyping and Testing
  • Production Tooling and Manufacturing
  • Plastic Part Prototyping Techniques
  • Assembly Techniques for Injection Molded Parts


Some knowledge of plastic materials, injection molding and engineering principles is useful, although the basics are introduced.


"The Professor was the best one I’ve ever had for a seminar or training class. I’m definitely going to come back to UW-Milwaukee for future classes."  —  Mary J. Glander, Task Force Tips

All sessions are Face-to-Face unless otherwise noted.

Mon.-Tue., Oct. 9-10


Location: UWM School of Continuing Education

Instructor: Robert Malloy


$990 if you register by Wed., Aug. 9.
$1,090 if you register after Wed., Aug. 9.

CEUs: 1.4, PDHs: 14

Enrollment Limit: 40

Program Number: 4830-10333

Registration Deadline: Mon., Oct. 9

Register Now