Understanding Injection Molding of Thermoplastics

– The key to optimum plastic part design

Dates: 21 – 24 June 2021
Time: 09:00 – 11:30 a.m.
Where: Online via MS Teams

The course focuses on the complex phenomena behind the Injection Molding process with a strong emphasis on the understanding of parts’ problems (aspect, shrinkage, warpage, weld lines, burns, etc.) and their relationship with material properties (amorphous, semi-cystalline, filled, unfilled) and the process itself. Each day different topics will be covered.

21 June:

  • Introduction to the process
  • Fundamentals of rheology including pressure dependence of viscosity

22 June:

  • Basic fiber orientation
  • Flow in simple geometries
  • Thermal effects and frozen skin dynamics

23 June:

  • Cosmetic issues and weldlines
  • Fundamentals of the packing phase

24 June:

  • Residual stresses
  • Shrinkage and warpage
  • Conclusions

Seminar Content

  • basic polymer thermal and rheological behaviour
  • effect of pressure on polymer properties
  • the flow process in Injection Molding
  • part geometry and flow pattern
  • compressibility, phase change and PVT data
  • what is crystallinity and how does it affect processing
  • the packing phase: key to the dimensional quality of the part
  • effective part, mould and process design for proper cavity packing
  • understanding the shrinkage build-up
  • part warpage mechanisms: designing for minimum warpage, according to material properties and part shape
  • warpage: the special case of fibre filled materials
  • the concept of residual stresses: the compromise with warpage
  • final conclusions and wrap-up – seminar evaluation by the participants

The seminar is not specifically about Injection Molding Simulation. However, the intention is to clearly help those among the participants who are “Flow Analysis users” to gain a thorough understanding of the concepts that form the basis of the existing code. Model assumptions and corresponding limitations will be highlighted and discussed.

The first part of the seminar will quickly describe the process cycle for the purpose of setting up a common vocabulary.

Target audience

  • design engineers in charge of molded parts
  • mold making specialists
  • molders
  • flow analysts looking for analysis interpretation support
  • project leaders involved in developing molded parts
  • research engineers interested in injection molding
  • mechanical engineers interested in process induced weakness and strength
  • material engineers or designers wishing to improve their understanding of a given class of materials (i.e. glass fiber filled polymers)
  • students involved in the field
  • young, skilled professionals with little field experience
  • flow analysis developers
  • customer support engineers

The seminar may not fit the needs of beginners in the field.

Vito Leo’s professional background
Vito Leo is a physicist by training (PhD from Brussels University), and has been working for more than 37 years in the field of polymer processing and mechanical performance of thermoplastics. He has been very active in the field of Injection Molding of Thermoplastics and the use of Finite Element Numerical Simulation of this process, initiating and managing a CAE Team in a large company.

He worked for the largest chemical company in Belgium in a number of research projects in the field of Rheology, Injection Molding, Mechanical performance of polymers and 3D Printing. For nearly 20 years he was Professor at Université Libre de Bruxelles, where he taught an introductory course in Polymer Processing to students of the Engineering Faculty nearly identical in content to his well-known seminar BIMS-1.

He is now full-time on the BIMS SEMINARS activities, expanding the training portfolio and starting consulting work in addition.

The Teacher’s word
“As a professional in the Plastic Industry for many years, I have met a very large number of people involved in this field: part designers, mold makers, molders, technicians on the shop floor, or academic people involved in fundamental research. I have always had the impression that everyone has a limited view of the problems, a good understanding in his particular field, but usually little knowledge of the process as a whole. Even worse, people usually do not understand each other because their job and training background are so different. Very few part designers or project managers know about the really peculiar behavior of molten polymers in a molding process. And no University Professor or Flow Analysis developer seem to know how a molding machine really works, or how a mold is made.

During my professional life I have tried to bridge the gap between those different approaches, being involved in academic research, attending conferences or training sessions, publishing papers, using software, but also spending a lot of time on the shop floor, running the machine myself, and working days and sometime entire weeks in molding shops throughout the world optimizing the process.

Flow Analysis Codes (Moldflow®, Moldex® and the likes) are now established and respected tools, readily available on PC and with excellent user interface and very good modeling capabilities. But optimum use and proper interpretation of results still require very skilled and experienced specialists. The users I come across are often young computer minded engineers, with limited knowledge of plastics and processing technology.

I also noticed that the recent boom in the Mobile Communications Business is generating extremely fast growth in leading companies, where very young professionals are now in charge of world-wide projects, involving complex plastic parts, special materials, and very demanding dimensional and mechanical requirements. These engineers would benefit from an appropriate training in Injection Molding and Polymer Physics.

Now that I have a good understanding of the molding process and the underlying physics, I want to try to share my knowledge with people in the industry.

The challenge I give myself is the following: I want to go deeply into the physics of the various thermoplastics processing behavior, thoroughly explain the mechanisms involved in this complex process from filling to final warpage, and yet present this seminar material with simple words and concepts, and minimum mathematics, so that the whole interested community, with or without high level university training, will benefit from these training sessions.”

Past participants have said
“It was amazing”, Dana-Maria Cobzaru, R&D Engineer, Novo Nordisk A/S
“All mechanical engineers need to go through the course”, Emil Gram Spork, Mechanical Design Engineer, Demant A/S

For more information on course content
Please e-mail Dr. Vito Leo at bims.seminars@gmail.com

21 – 24 June 2021

Registration fee

DKK 9,175 Members of ATV-SEMAPP and IDA Polymer
DKK 9,675 Non-members

Includes sessions during the four days & educational materials. Participants will receive a certificate after completing the course.

All prices are excluded of Danish VAT 25%.

Save 1,000 DKK when registering before 1 April 2021.

Registration closes at 25 participants.

Binding registration
Registration is binding, however substitutions are accepted at any time.

Understanding Injection Molding of Thermoplastics, 21 - 24 June 2021

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