Injection Molding Process Technology

Resin behavior and drying, machine/screw/melt profiles, filling and packing, cooling and mold temperature, and the complete 18-defect troubleshooting matrix.

Private cohorts & on-site
Format: 3-day (8:30 a.m.–4:30 p.m.)
Level: Intermediate
Location: Scheduled on demand · on-site at your facility or a regional venue
Date(s): Not yet scheduled for open enrollment. Get notified when it is, or book it privately for your team.
Includes: Certificate of Completion · printed slide binder · take-home reference text

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One email when dates are set. Or skip the wait: run it as a private cohort, on-site at your plant.

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Faculty

Faculty details for this seminar will be announced with the full schedule.

Fees

Early: $1,895 (payment 4+ weeks ahead)
Standard: $2,095 (check/ACH) · $2,165 (card)

Group discount: $200 off per attendee for 3+ from the same organization.

Also Available

  • Corporate on-site delivery at your facility
  • Private cohort sessions
  • Digital curriculum licensing

Seminar Overview

Injection molding is the dominant plastics conversion process in automotive, medical, electrical, and consumer manufacturing, yet most molding problems are solved by trial-and-error at the machine rather than from first principles. This seminar replaces folklore with the scientific molding method, taught directly from the primary-source processing literature: the DuPont molding guides for Delrin® acetal, Crastin® PBT, Zytel® nylon and Minlon® reinforced nylon; the Victrex PEEK injection and compression molding guides; the BASF Ultramid® processing documentation; and the Covestro part and mold design guide, together with the RJG process documentation and certification curriculum that underpin modern data-driven molding.

Because the course is built on the actual resin-supplier processing windows and the RJG machine-and-process instrumentation method — not vendor slide decks or marketing material — attendees learn the same melt-temperature, fill-speed, pack-and-hold, and cooling logic that resin and process-instrumentation engineers use. Every module closes with a troubleshooting matrix (short shot, flash, sink marks, voids, warpage, weld lines, splay, burn marks, delamination, brittleness) worked from the documented cause/effect relationships in the primary sources.

Attendees leave able to establish a scientific molding process from scratch, document a repeatable process window, qualify a resin lot change or machine-to-machine process transfer, and diagnose defects by their signature rather than by knob-turning. The course is intermediate level: attendees should have hands-on exposure to injection molding and want to move from operator-level to engineer-level process control.

Ideal Learner

  • Process and manufacturing engineers responsible for injection molding operations
  • Molding technicians and supervisors pursuing scientific / data-driven molding certification
  • Design and materials engineers who specify resins and must understand process effects on properties
  • Quality engineers tasked with molding defect investigation and PPAP/process validation
  • Automotive tier suppliers, medical device molders, electrical/electronic connectors, consumer products

Learning Objectives

  • Establish a documented scientific molding process (viscosity curve, cavity balance, pressure drop, gate seal/fill-only weight, cooling rate) from machine data rather than trial-and-error
  • Set melt temperature profiles, screw design parameters, and back pressure appropriate to the resin family from the supplier's processing documentation
  • Select fill speed, boost (injection) pressure, hold (second-stage) pressure/time, and cooling time using the primary-source guidance and confirm gate seal by fill-only weight
  • Specify correct drying conditions for hygroscopic resins (nylon, PBT, PEEK, PC, TPU) and recognize moisture-related defect signatures (splay, silver streaks, hydrolysis, brittleness)
  • Diagnose short shot, flash, sink marks, voids, warpage, weld/knit lines, burn marks, delamination and brittleness by matching defect signature to process/mold/material cause

Consulting Sessions

Seminar attendees can sign up for individual consulting sessions with the instructor. Sessions are free for registered attendees, first-come first-served — sign up when registering by calling 248-539-0473 or during the seminar.

Seminar Outline

  • Polymer rheology from the supplier guides: viscosity, shear thinning, melt flow in the machine and mold
  • Amorphous vs. semi-crystalline behavior — why Delrin acetal, Zytel/Minlon nylon, Crastin PBT, and Victrex PEEK each demand different process discipline
  • Moisture in hygroscopic resins: why wet nylon fails, drying temperatures/dewpoints per the DuPont and BASF documentation, PEEK-specific drying
  • Moisture defect signatures: splay, silver streaking, hydrolyzed molecular weight loss, weld-line weakness
  • **Exercise 1: compute the correct drying window (temperature, time, dewpoint) for a nylon and a PBT part and predict the defect signature if drying is skipped**
  • Injection unit anatomy: clamp, barrel, screw/check-ring, nozzle — from the RJG process documentation
  • Screw design fundamentals: compression ratio, L/D, flight geometry, barrier screws vs. general-purpose screws for crystalline resins
  • Melt temperature profiles across the barrel zones; nozzle temperature; residence time and thermal degradation limits for acetal, PBT, nylon, PEEK
  • Back pressure: mixing, color dispersion, and melt uniformity vs. shear degradation
  • **Worked example: barrel profile for glass-filled Crastin PBT versus unfilled Delrin — and what happens when profiles are copied between resins**
  • First-stage (boost) injection: velocity-controlled filling, why fill speed dominates part quality
  • The viscosity curve (rheology) study from the RJG method — finding the "best" fill speed from the flat portion of the relative-viscosity plot
  • Cavity balance studies, pressure-drop studies, and fill-only (short shot) weight series
  • Multi-cavity imbalance: natural imbalance vs. tooling-induced imbalance and corrective levers
  • **Exercise 2: build a complete first-stage setup (viscosity curve interpretation, cavity balance decision, fill-only weight ladder) from supplied machine data**
  • Second-stage (hold) pressure and time; the gate-seal study and fill-only weight confirmation
  • Sink marks and voids: thick/thin section effects, pack pressure transfer, coring decisions per the Covestro part design guide
  • Hold-pressure profiling; overpacking effects — stress, flash, dimensional change, ejection problems
  • Cooling time determination and its interaction with hold time; crystallinity effects in acetal, PBT, nylon, PEEK
  • **Worked example: eliminating sink on a thick boss without creating flash — pack profile from the primary sources**
  • Mold temperature controllers, chillers, and the effect of mold temperature on crystallinity, shrinkage, and warpage
  • Cooling-time fundamentals and the dominant-role of wall thickness; conformal vs. conventional cooling concepts
  • Warpage: differential shrinkage, differential cooling, orientation — diagnosis from part distortion pattern
  • Thermal degradation: residence-time discipline for PEEK and acetal; purging and shutdown procedures per the supplier guides
  • **Exercise 3: warpage diagnosis from a distortion signature (saddle/bow/twist) back to differential cooling, differential shrinkage, or orientation**
  • Injection molding of PEEK per the Victrex guide: melt temps, mold temps, post-crystallization/annealing, high-temperature mold requirements
  • Compression molding of PEEK and reinforced thermoplastics: charge placement, press cycles, flow/solderless fusion, fiber orientation consequences
  • Process economics and part-property tradeoffs: fiber orientation and anisotropy, weld lines in injection vs. compression
  • When compression wins: very thick sections, continuous-fiber or heavily filled compounds, low-volume large parts
  • **Worked example: injection vs. compression decision for a thick-section PEEK component — property and cost consequences of each route**
  • The ETS troubleshooting matrix: defect → signature → candidate causes (process / mold / material / machine) → corrective levers
  • Weld lines and knit lines: formation, meeting-angle effects on strength per the Covestro guide, melt temperature/fill speed remedies
  • Flash: clamp tonnage, venting, injection speed/pressure, viscosity effects — flash as a symptom, not the disease
  • Short shot: venting, fill speed, vent/runner/gate sizing, material viscosity variation, machine capability limits
  • Burn marks / gas traps: venting and fill-speed discipline
  • Delamination and contamination signatures: residual regrind, foreign resin, mold release, wet vs. dry blending
  • Brittleness: molecular-weight loss (overdrying, over-shearing, thermal degradation), weld-line stress, notches and stress concentrators
  • **Case History: a multi-cavity family mold with cavity-to-cavity variation traced to imbalance plus moisture — full diagnosis chain from the primary-source method**
  • **Exercise 4: capstone — hand each attendee a defect signature and machine data set; produce the full diagnosis and corrective plan and defend it**

More in Track C — Design, Molding & Tooling

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