The textbook · 30 years · 12 editions in two languages
The book the industry learned plastics from.
Designing Plastic Parts for Assembly by Paul A. Tres, Fellow of the Society of Plastics Engineers. First published by Carl Hanser in 1994, revised ten times since, translated into Chinese twice — and the spine of every ETS seminar, design review and expert opinion.
ISBN 978-1-56990-912-6 · 474 pp · full colour · also on the SPE bookstore
Who wrote the front matter
Not blurbs. Signed essays from the people who build the cars.
Every edition opens with a preface or foreword by a working engineer, an executive or trial counsel — two SAE presidents, the CEO of SPE, a Tesla senior engineer, Mercedes-Benz, DENSO, Schaeffler, Bayer and Chrysler. Read them in full below. They say what the book actually does on a production floor.
has become must–have literature for anyone joining the interiors design department at Mercedes–Benz U.S. International.
DENSO utilizes many of the topics presented in this book.
I look forward to more of his books on plastic design, manufacturing, and assembly.
The book is thus much more than its title suggests.
Paul did it. I did not..
Thirty years on the shelf
Ten editions. Every one revised from the field.
Each edition absorbed what the seminars and the expert-witness work turned up since the last one. Hover a spine; click through to its front matter.
What’s inside the 10th edition
Eleven chapters. Material to fastener.
The book walks the same path a part takes: understand the polymer, size the safety factor, run the strength-of-materials math, respect the nonlinearity — then join it. Welding, press fits, living hinges, snap fits, bonding, in-mold assembly and fasteners each get the design rules, the worked equations and the case histories where someone got it wrong.
The free snap-fit and living-hinge calculators on this site implement chapters 7 and 8.
- Understanding Plastic MaterialsThermoplastics vs thermosets, crystalline vs amorphous behavior.
- Understanding Safety FactorsWhat a safety factor means across a product’s life expectancy.
- Strength of Material for PlasticsTensile testing, stress–strain, pull rates that mimic hand vs automated assembly.
- Nonlinear ConsiderationsWhen polymers stop recovering to their original dimensions.
- Welding Techniques for PlasticsUltrasonic, vibration, spin, hot-plate, laser, electromagnetic and the new hot-gas subchapter.
- Press FittingForce-fit joints between like and unlike materials.
- Living HingesIntegral hinges molded in one tool, and the materials that survive them.
- Snap FittingHook-and-groove lock arms — deflection, strain and retention.
- BondingAdhesive and solvent bonding, surface preparation, chemistry.
- In-Mold AssemblyOvermolding and multi-material molding, from tail lights to toothbrushes.
- FastenersScrews, bolts, metal inserts, clips and spring washers in plastic.
The archive · 1993 – 2024
Every preface and foreword, in full.
Fourteen essays to the English editions, newest first. Each opens on its own reading page with the edition cover, the signature block and links to the next.
- 2024 Preface · 10th editionPaul A. TresFellow of the Society of Plastics Engineers · ETS Inc. · Bloomfield Hills, Michigan Read →
- 2021 Foreword · 9th editionJeff Hemphill2020–2021 President, SAE International · Chief Technical Officer, Schaeffler Group USA · Wooster, Ohio Read →
- 2021 Preface · 9th editionNeelam KaswaSenior Mechanical Engineer, Tesla Inc. · Fremont, California Read →
- 2017 Foreword · 8th editionDouglas E. Patton2017 President, SAE International · EVP & Chief Technical Officer, DENSO International America · Southfield, Michigan Read →
- 2017 Preface · 8th editionWim De VosCEO, Society of Plastics Engineers · Ronse, East Flanders, Belgium Read →
- 2014 Preface · 7th editionDavid M. Paris, Esq.Nurenberg, Paris, Heller & McCarthy Co., L.P.A. · Cleveland, Ohio Read →
- 2006 Preface · 6th editionJeff Lubbers, PEMercedes-Benz U.S. International · Tuscaloosa, Alabama Read →
- 2003 Preface · 5th editionJoerg-Uwe Szipl, Esq.President, Griffin & Szipl, P.C. · Washington, D.C. Read →
- 1999 Preface · 4th editionDr. Kishor S. MehtaTechnical Manager, Bayer Corporation · Pittsburgh, Pennsylvania Read →
- 1998 Preface · 3rd editionGlenn L. BeallPresident, Glenn Beall Plastics, Ltd. · Libertyville, Illinois Read →
- 1995 Foreword · 2nd editionHenri (Ari) SayagResearch Manager, Mecaplast · Monte Carlo, Monaco Read →
- 1994 Preface · 2nd editionJohn E. FillionManager, Organic Materials Engineering, Chrysler (later Fiat Chrysler Automobiles North America) · Auburn Hills, Michigan Read →
- 1994 Foreword · 1st editionDr. Donald E. BaxaUniversity of Wisconsin–Madison · Madison, Wisconsin Read →
- 1993 Preface · 1st editionDr. Peter DewhurstDepartment of Industrial & Manufacturing Engineering, University of Rhode Island Read →
塑料零件装配设计 · Chinese editions
Translated for the world’s largest plastics industry.
The first Chinese edition (Chemical Industry Press, Beijing) carried a new preface by the author written for designers across aerospace, automotive, computers, furniture, medical and packaging. The 8th edition followed from China Machine Press with the DENSO foreword and the SPE preface.
2017 President, SAE International · EVP & CTO, DENSO International America
Read → Preface · 8th Chinese edition · 2017 Wim De VosCEO, Society of Plastics Engineers
Read → Preface · 1st Chinese edition · 2002 Paul A. TresETS Inc. — preface to the first Chinese edition
Read →Read before you buy
Two free lectures, straight from the text.
Both are PDF excerpts of real seminar sessions built on the 7th edition.
The Honda pitfall case and the step-by-step procedure for catching it before steel is cut. ©1992–2015 Paul A. Tres.
Download the excerpt → PDF · PD3 session, 2015 Snap-Fits Which KillThe influence of color on plastic product failure — pigment-driven degradation, investigated from the 7th edition.
Download the excerpt → Video · 51 minutes The Plastic Part Design webinarThe author working a full design problem on camera — the closest thing to opening the book with him.
Watch →Where to get it
Three ways to own the 10th edition.
474 pages, full colour, January 2024. ISBN 978-1-56990-912-6.
Buy hardcover →The same 10th edition in digital form. ISBN 978-1-56990-939-3.
Buy eBook →Three days in Grand Rapids, October 20–22, 2026 — the book taught by the man who wrote it, with a 20-minute one-on-one.
Seminar details →Also available through the Society of Plastics Engineers bookstore. Corporate libraries ordering for a training cohort: ask about seminar bundles.
The whole practice
One record. Eight ways to use it.
Three days in Grand Rapids with the author. 1,300 slides, real case histories, twenty minutes with him.
90 coursesThe catalogFailure, composites, EV, crash, compliance, regulated product. Open enrollment, in-plant, or your own cohort.
Your floorIn-plantThe same course at your plant, on your parts. Sixty-three companies have already hosted it.
The book10th editionDesigning Plastic Parts for Assembly. The seminars are taught from it. Read the prefaces first.
The recordExpert witnessTrial and deposition work since 1997. Plastics failures, explained to a jury.
The toolsCalculatorsSnap-fit and living-hinge, free. The same equations the seminar spends a day on.
Cited answersChatETSAsk the corpus. Answers come back with the source, not a guess.
The workspaceETS BuildDesign, FEA, DFM, PPAP and FMEA in one browser. Early access for pilot teams.
Next step
See it taught, live.
The October 20–22 seminar in Grand Rapids is built on this book: 1,300 slides, real case histories, and a 20-minute session with the author for every attendee.
- NDA on request
- Senior engineer replies in one business day
- Fixed price where applicable
- Your data stays yours