Understanding Injection Molding of Thermoplastics

– The key to optimum plastic part design

Dates: 25-28 August 2020

Time: 9.00-11.30 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.

25 August:

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

26 August:

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

27 August:

• Cosmetic issues and weldlines
• Fundamentals of the packing phase

28 August:

• 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, and has been working for more than 35 years in the field of Polymer Processing. He is particularly active in the field of Injection Molding of Thermoplastics and the use of Finite Element Numerical Simulation of this process.

He works for the largest chemical company in Belgium and is currently involved in a number of research projects in the field of Rheology and Injection Molding. He is also in charge of the Flow Analysis group that uses available commercial software to support injection-molding customers.

His well known expertise has recently gained him a position as Professor at Université Libre de Bruxelles, where he is currently teaching an introductory course in Polymer Processing to students of the Engineering Faculty.

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.

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

Registration fee

Early bird discount of DKK 300,- applies when registering before 30 May 2020.

Registration closes at 25 participants.

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