SEMINAR VII - SCIENTIFIC INJECTION MOLDING TECHNOLOGY

John Klees Enterprise, Inc. - 125 Caldonia Drive - Candler, NC  28715
Phone: 828.667.0580  -  Fax: 828.667.0830  -  E-mail: jklees@johnklees.com

This four day, total 32 hours, seminar, presented by John Bozzelli and John Klees, is targeted towards process understanding, process development and process optimization. This seminar is a combination of John Klees' "Injection Molding Technology" (seminar #I) and John Bozzelli's "Scientific Injection Molding". This seminar is specifically designed for people who start up a new mold or people who must optimize existing cycles, as well as personnel responsible and accountable for quality molded product molded at a competitive cost. Injection molding workshops supplement the classroom material, so you will be involved with actual machine operation. Relationship between hydraulic pressure, plastic pressure, cavity pressure and on-machine rheology are demonstrated. Emphasis is placed on practical setup procedures, which will optimize the overall molding cycle.

At this seminar you will....

  • Receive individual attention and machine side instruction due to our small group atmosphere.
  • Understand the basics of rheology, what it means to product design, to mold design, and to the molder.
  • With the help of a video, witness how a polymer flows and orients into the mold.
  • Learn points to be considered in selecting an injection-molding machine.
  • Learn why a close loop system is not smart enough to compensate for poorly trained operating personnel.
  • Be involved with actual machine setup and fine-tuning operation.
  • Learn how to master efficient production of precision molded products.
  • Return with broader insights that can immediately be applied to improve the profitability of your injection molding operation because you learned process optimization via scientific injection molding.
  • Receive a comprehensive custom-developed instruction manual, provided only to participants of this seminar, which will serve as a valuable source in the future.

Seminar Outline

I     Characteristics Of Polymeric Materials

  • Introduction to polymer chemistry from monomer to macromolecules, intermolecular forces, molecular weight distribution.
  • Polymer viscosity characteristics.
  • Shear rate, shear stress and viscosity versus injection speed.
  • Molecular orientation and flow into the mold.
  • Gate location(s) versus orientation, weld lines, mold venting and shrinkage.
  • Shrinkage versus wall thickness and mold temperature.
  • Homopolymers; copolymers and terpolymers; crystalline and amorphous materials; crystal structure and spherulites growth during the mold cooling process and it's influence on product rigidity; toughness and elongation.
  • Understanding hygroscopic polymers and drying procedures.
  • Understanding the General Test Methods of Plastic: tensile, melt-index, impact strength, etc.

II    The Injection Molding Machine

  • Injection molding machine terminology. Development of the injection unit. The reciprocating screw machine. Importance of screw design; L:D and compression ratio considerations; mixing screws. Check valve assemblies; nozzle and nozzle adapters and application of shut-off valves.
  • Hydraulic injection pressure versus plastic pressure (intensifying ratio); injection speed; packing and holding pressures and time; cushion control; temperature set-up parameters; back pressure control and screw R.P.M.  Gas assist injection molding.
  • Vented screw and barrel; functional zones of the screw; starve feeding versus flood feeding.
  • Toggle and hydraulic clamping mechanisms; clamp unit specifications; parallelism of machine platen; wrap around; machine levelness; and tiebar equalizing procedure. Two-platen clamping technology and tiebarless machines. Ejector mechanism. Standard SPI core pull sequences and auxiliary ejector mechanisms.
  • Standard SPI core pull sequence machine and cycle efficiency factors.

III    Microprocessors

  • Process-control; clamp set-up; ejector set-up; injection velocity profile; holding pressure profile; temperature set-up; process-timers; extruder R.P.M. and back-pressure.

IV    Industry introduction

  • Perspectives on the plastics’ industry. (size, profit margins, etc)
  • What is your product? (size, shape, material, and other characteristics required)
  • Injection molding’s position relative to other plastic processing methods
  • The components of a successful plastic’s application
  • Concurrent engineering and its benefits

V    Strategies for Injection Molding

        The four plastic variables:    

  • Melt Flow Rate (MFR) versus processability
  • Viscosity versus injection velocity cure; viscosity versus shear rate
  • How to control flow on an injection molding machine
  • Optimizing second stage

VI    Two stage molding

  • Alternate names: Velocity Controlled molding.
  • Systematic or decoupled molding SM (RJG Associates)
  • Development of the technique
  • Implementation

VII    Cooling Process

  • Characteristics of mold cooling, flow of cooling media and layout of cooling channels.

VIII    Case studies/Molding problems and solutions

  • Surface imperfections, warpage, voids, sinks, etc.

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