Injection Molding (Plastic) Apprenticeship

Injection Molding (Plastic) Program Outcomes

  • Plastic Structure and Properties – Explain the polymerization process. Compare linear, branched, and cross-linked structures. Describe the functions of additives such as plasticizers, lubricants, fillers, and reinforcements.
  • Introduction to Injection Molding – Describe the functions of the major components of an injection molding machine. Compare toggle and hydraulic clamping systems. Describe the various types of screw tips. Explain the purpose of back-pressure. Compare plastic pressure to hydraulic pressure.
  • Mold Installation and Start-up – Determine maximum and minimum mold size. Explain the purpose of the locating ring. Describe the step-by-step process of clamping a mold to the platens. Establish molding parameters such as shot size, barrel temperatures, injection speeds and pressures, pack, hold, and cooling times, ejector stroke, and mold opening and closing speeds.
  • Mold Design and Construction – Explain the function of various mold components. Select the appropriate metals for cavities, cores, and mold bases. Describe the different machining operations that may be used to produce mold cavities, cores, and bases. Calculate runner, gate, and venting requirements. Demonstrate mold polishing techniques.
  • Blueprint Reading – Understand and interpret the types of lines used on shop drawings and part prints. Apply tolerances and symbols. Identify threads, tapers, and machined surfaces. Develop good sketching techniques.
  • Mathematics – Fractions, decimals, ratio and proportion, cutting speeds and feeds, basic algebra, geometry and trigonometry.
  • Inspection Procedures – Use precision measuring instruments to inspect plastic parts. Examine plastic parts for visual defects. Describe corrective action to eliminate defects.
  • Machine Shop Practices – Safely operate basic machine shop machines such as saws, lathes, mills, drill presses, and grinders to produce simple parts when a qualified toolmaker is not available.