SEMINAR II - INJECTION MOLD DESIGN

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

This three day, total 24 hour, seminar offers a thorough review of the Fundamental Mold Design requirements, and concentrates on the design elements that are necessary to produce a sound operational injection mold.

This course is intended for, and will benefit all professionals involved in the injection molding and tool manufacturing process, such as tool designers, liaison engineers, toolmakers and mold maintenance personnel, set-up personnel, tool room and molding room management personnel.  It is also designed as a continuation for those individuals who have previously attended seminar #I, Injection Molding Technology.

Practical technology and underlying mold engineering principles will be lectured during this presentation.

At this seminar you will....

  • Increase understanding of the major considerations required when evaluating injection molding machine specifications and how to relate this technical data to mold design and material processed.
  • Be introduced to the fundamental components which compose the injection mold.
  • Understand the nomenclature.
  • Evaluate the basic mold lay-out and learn how to scrutinize the design concept.
  • Take a subject of unique complexity and reduce it to a subject almost of simplicity
  • Receive a source of technical information tempered with a considerable amount of practical hands-on experience.
  • Learn to design for competitiveness through proven concepts for mold manufacturing technology.
  • Comprehend the segments on techniques, allowing one to communicate efficiently with the mold maker, and developing a practical outlook which benefits the project's end result.
  • Broaden your skills on the selection of tool steels and other materials used in the moldmaking industry.
  • 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     Mold Engineering principles

  • Mold filling.
  • Gate location(s), Polymer orientation and effects on shrinkage, core deflection weld lines and vent locations.
  • Parting line location.
  • Cooling requirements; effect on crystal structure, physical and dimensional characteristics.
  • Effect of molding conditions and wall thickness on mold shrinkage.

II    Review of the injection molding machine specifications

  • Rated clamping force, opening force, platen size, distance between tie-bars.
  • Mold height (min-max), or daylight (min-max), mold opening stroke, ejector stroke and ejector force, K.O. bar location(s).
  • Rated injection capacity, injection velocity (max), injection rate and injection pressure, plasticizing capacity.
  • Nozzle stroke, nozzle contact force and nozzle penetration past stationary platen.

III    Some basic calculations

  • Determination of shot weight and clamping force requirement.
  • Estimating cooling and cycle time.
  • Estimating ejection force requirement, relating to the type of ejection selected.
  • Cavity side walls and estimated amount of deflection.

IV    Introduction to Injection Mold Design

  • Terminology used in the moldmaking industry
  • Two plate molds
  • Three plate molds
  • Stack molds
  • Interchangeable mold frames
  • Specialty molds: Unscrewing mold, Prototype mold base, MUD frames, Combination mold, Roundmate® 

V     Runner lay out, type of gates and mold venting

  • Sprue bushings and sprue puller designs.
  • Runner lay out, runner configuration and recommended runner sizes. Balancing runner systems.
  • Gate types: standard gate, fan gate, direct sprue, ring gate, film or flash gate, tab gate pinpoint gate, submarine or tunnel gate, curved tunnel gate, chisel gate.
  • Venting: perimeter venting, ring venting, venting with lamina assembly, ejector pin venting, etc. Recommended vent depth versus molding material.

VI   Mold components

  • Cavity and core inserts, core pin application(s) and method of cavity and core locating. Through pocket, blind pocket, channel pocket, etc.
  • Support pillars and riser blocks.
  • Leader pin and leader pins bushings, parting line interlocks.
  • Ejector pins, stop pins, ejector pin assembly. Ejector blades and sleeves. Guided ejector mechanism.
  • Stripper plate and stripper rings, delayed stripper ejection. Ring and bar ejector system.
  • Air ejector systems and vacuum breaks. Programmed ejection.

VII    Mold Cooling

  • Basic water cooling theory. Velocity of cooling media. Reynolds, Prandtl and Nusselt numbers. Heat coefficient transfer. Thermal conductivity and specific heat of the cooling media and how to influence the quantity of heat to be extracted from the mold.
  • Methods of applying cooling to the mold: Waterline lay out and cooling passage designs: baffles, cascades, inserts, etc. Seals and O ring installation. Thermal conductivity of materials used in the mold making industry.
  • Heat pipes (latent heat of evaporation).
  • Vacuum cooling

VIII   Materials used in mold making

  • Structure of steel. Tool steel alloys. Principle function of alloying elements in tool steel. Heat treatment (annealing, stress relief, hardening, case hardening). Nonferrous materials used in the mold making industry. Tool surface enhancements commonly used in the Plastic Processing Industry.

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