Introduction to the Design Guide
Part One: The Rotational Molding Industry
- Overview
- Typical Rotomolding Applications and Markets
- The Rotational Molding Process
- Rotational Molding Machines
- Molds for Rotational Molding
- Common Plastic Materials for Rotational Molding
- Other Plastic Materials, Composites and Additives
Part Two: Designing Products for Rotational Molding
- Overview
- Nominal Wall Thickness & Wall Thickness Limits
- Wall Thickness Uniformity
- Flatness Considerations
- Minimum Wall Separation & Bridging Defects
- Corner Angle Limits
- Reinforcing Ribs
- Kiss-Off Ribbing, Single Point Kiss-Offs and Kiss-Throughs
- Draft Angles, Shrinkage & Warpage
- Corner Radii
- Holes
- Undercuts
- Tolerances
- Molded-In Threads
- Molded-In Inserts
- Finishing, Decorating & Other Post-mold Operations
- Development of Product Designs and Tooling using Digital Methods
Introduction
This document is a significant revision of ARM's "green book," The Introductory Guide to Designing Rotationally Molded Plastic Parts, originally published in 1982. A number of ARM members contributed to the original publication, including significant work by Glenn Beall.
The revision was written by Dr. Nick Henwood with contributions from the ARM Education Committee.
The publication is dedicated to the memory of Tom Wyszynski, who assisted with rewriting the guide.
This Design Guide answers the following four basic questions, and many others:
- What is the rotational molding process?
- What are its advantages to users?
- How do you design rotationally molded parts?
- What plastics can be molded?
You should find this guide useful whether you are a designer, a specifier, or a buyer of rotationally molded parts. The sections which follow will provide a better understanding of rotational molding, what it offers the design engineer, the unique capabilities of the process and the inputs required to successfully design parts.
A Word about the Information Being Presented
The information presented in this booklet has been collected from many sources which are believed to be reliable and is provided in good faith; however, no warranty of any kind, express or implied, warranty can be made to its accuracy, adequacy, validity, reliability or completeness. ARM assumes no responsibility or liability for any loss or damage suffered through reliance on any information contained herein. The final determination of the suitability of any information for the use contemplated for a given application remains the sole responsibility of the user.