Plastic Injection Mold Design: Basic and Advanced Topics

In this plastic injection molding course, you’ll enjoy a comprehensive exploration of injection mold design that not only enhances your understanding but also equips you to drive overall project success. Through a unique approach, you’ll gain a profound comprehension of detailed mold design concepts set forth in the context of the whole design process.

As you progress, you’ll cultivate a strategic mindset for achieving cost savings throughout the process, and review projects at each important juncture to master advanced concepts.

By enrolling in this course, you’ll emerge with an enriched perspective on injection molding and design, equipped to make significant contributions to projects’ triumphs through your comprehensive grasp of both design intricacies and cost-efficient strategies.

This course can be applied to the Plastics Technology Certificate.


Erik Foltz

Erik Foltz is a certified professional Moldflow® consultant at The Madison Group. Foltz received his MS from the Polymer Engineering Center at the University of Wisconsin-Madison. Foltz’s work concentrates on assisting industrial clients accelerate the product design process through the ... read more

Who Should Attend

Anyone responsible for procuring, evaluating, building or designing injection mold tools, including tooling engineers, buyers, toolmakers, mold designers, product designers, managers and molders.

Benefits and Learning Outcomes

  • Learn to do advanced cavity and core inserting
  • Analyze your current issues regarding plastic injection molding
  • Understand mold design concepts
  • Avoid costly mistakes
  • Specify and evaluate your purchases of molds
  • Understand advanced parting line, shut-off development, advanced slide and lifter design

Course Outline/Topics

Day 1 & 2

Introduction and Overview

The Anatomy of a Mold

Mold Types

  • Stripper plate molds
  • Unscrewing molds
  • Quick change molds
  • Hot runner molds
  • Shuttle molds

Basic Mold Construction

  • Use and placement of bolts and dowels
  • Major suppliers and differences between them
  • How to specify and order mold bases and components

Common Components and their Function

  • Leader pins, return pins, support pillars, rest buttons, etc.

The Molding Press

  • How the mold interfaces with the press
  • Horizontal and vertical clamp
  • Shuttle and rotary presses

Plastic Resin Fundamentals

  • Amorphous and semi-crystalline
  • Basic properties and how they affect the mold design


  • How to use shrink to your advantage
  • Factors that affect shrink and warp

Plastic Product Design Fundamentals

  • Common errors
  • What the mold designer needs to look for in a product design

Sprue, Runner and Gate

  • Common gate design errors
  • Runner sizing guidelines
  • Runner pullers


  • Determining ejector place
  • Pin orientation methods
  • Knock-out patterns
  • Return pins and springs

Basic Mold Inserting

  • Solid vs split construction
  • Criteria for inserting

Slides and Lifters

  • A thorough look at how to mold undercuts
  • Typical slide and lifter construction
  • Mechanical vs hydraulic

Cavity Layout

  • How to efficiently “place“ the cavities in the mold and choose the best parting line
  • How it affects runners, ejection and gates


  • The economic effect of cooling design
  • General rules for waterline placement
  • Thermal conductivity of various tool steels


  • Venting of runners
  • How venting affects the molded part
  • Why this should NOT be overlooked

Mold Steel

  • What to look for in a mold steel
  • A discussion of steel hardness
  • Alternate materials used in molds

Plating and Polishing

  • A selection chart for mold coatings
  • When and why to use plating

Day 3

  • Structural design considerations
  • Ejector pin placement
  • Support pillar/plate thickness calculations
  • Fit tolerances/machining precision
  • Mold and part design considerations for multi-shot molding
  • Core shift

  • LSR and HCR mold design considerations
  • Unscrewing collapsible core technology
  • Mold maintenance considerations
  • Injection molding simulation for toolmakers/tool designers for driving engineering decisions

Date: Tue-Thu, Sept 17-19, 2024

Delivery Method: In-person

Time: 8am-4pm CT

Location: UWM School of Continuing Education

Instructor: Erik Foltz


$1,485 by Sept 3, 2024
$1,645 after Sept 3, 2024

CEUs: 2.1, PDHs: 21

Enrollment Limit: 20

Program Number: 4830-16304

Registration Deadline: Sept 10, 2024

Register Now


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