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This four day, 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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