Injection Molding Terminology Glossary 2025

Introduction to the Industry Glossary

The plastics injection molding industry is entering an era of intensive digitalization. With advancements in Tederic NEO technology, the shift to servo-electric drives, and integration of MES/MOM systems, demand is growing for unified terminology covering both traditional molding parameters and concepts related to AI, IoT, and carbon footprint. This injection molding glossary was developed as a comprehensive knowledge resource for designers, process engineers, automation specialists, and production teams.

The article combines classic definitions (clamping force, holding pressure, hot runner system) with practical application examples (e.g., how to calculate OEE for an injection cavity or understanding the differences between PCR regrind and PIR in automotive production). This makes the material a complete technical knowledge compendium for the entire production team.

What is an injection molding glossary?

Injection molding plastics glossary is an organized set of terms describing every stage of the process: from pellets to quality reports. It covers definitions of technical parameters, machines, materials, design tools, quality standards, and efficiency metrics. Each entry includes the Polish term, common English translation used in OEM documentation, abbreviations, reference values, and application context.

The primary goal of the glossary is to facilitate communication between process engineering, production teams, and end customers while ensuring consistent understanding of technical terminology across the entire organization.

Methodology and entry structure

We applied a systematic approach, where each entry is assigned to a larger thematic category. This enables the glossary to cover:

• Basic concepts – definitions of process fundamentals, injection cycle description, mold and cavity elements.
• Parameters and metrics – numerical values, equations, and practical monitoring methods.
• Materials and additives – engineering polymers, elastomers, composites, biopolymers, and regrind.
• Machines, peripherals, and automation – injection molding machines, robots, hot runner systems, cooling, drying.
• Digitalization and standards – MES, SCADA, IoT, PPAP, APQP, IATF 16949 guidelines, and ISO 13485.

Each entry includes detailed technical information and practical application examples, making it easy to quickly find answers to specific questions (e.g., how to calibrate a mold pressure sensor, what does Cpk mean for LSR injection).

Injection molding term categories

The glossary covers five main thematic categories to simplify navigation:

1. Process – definitions describing the injection cycle sequence, machine settings, parameter control.
2. Technologies and equipment – terms related to Tederic injection molding machines, molds, automation, and peripherals.
3. Materials – base polymers, additives, regrind, rheological indicators.
4. Quality and standards – PPAP documentation, audits, statistical methods, traceability tools.
5. Strategic trends – Industry 4.0, AI, ESG, circular economy, CO₂ reporting.

This grouping enables easy identification of related concepts and understanding their interrelationships in the context of the entire production process.

Basic injection process concepts

The following terms form the foundation of the injection molding process and are essential for daily work of technologists and operators:

• Injection cycle – full sequence of injection molding machine movements: closing, injection, holding, cooling, opening, ejection. Cycle optimization determines cavity takt time.
• Plastics injection molding – process of plasticizing pellets and forming the molded part in the mold using high pressure and controlled temperature.
• Molded part – finished component formed in the mold cavity; defined by weight, dimensional tolerance, texture, and color.
• Molding cavity (cavity) – space matching the molded part shape; molds can have single or multiple cavities (multi-cavity, family mold).
• Runner system – set of channels directing molten polymer from the nozzle to cavities; includes cold runner and hot runner systems.
• Sprue – central feed channel branching into point, edge, or fan gates.
• Holding pressure – post-injection pressure phase compensating for material shrinkage; affects density and prevents voids.
• Cooling time – longest cycle phase, dependent on wall thickness, mold conductivity, and cooling system efficiency.
• Degassing and venting – air removal from cavity via vent gaps; minimizes burn marks and diesel marks.
• Clamping force – tonnage required to keep mold closed against injection pressure; selected based on projected molded part area.
• Injection unit – screw, barrel, heating zones, and nozzle assembly responsible for plasticizing pellets.
• Clamping unit – injection molding machine section handling movable platen motion, toggle or column mechanism maintaining clamping force.
• Process window – range of parameters where the process remains stable and meets specs; established via DOE and SPC analysis.
• Hot runner – heated nozzle system keeping material molten up to the gate, eliminating sprues.
• Stack/cube molds – multi-level molds increasing cavity count without raising clamping force; used for high volumes.

Materials, additives, and properties

Polymer selection determines process parameters, costs, and recyclability. Key material terms:

• PP (polypropylene) – versatile semi-crystalline polymer; homo-, copolymer, impact-resistant grades. Processing range 200–240°C, shrinkage 1.2–2,5%.
• PE-HD / PE-LD – high- and low-density polyethylene used in packaging, automotive, and medical applications. MFR 2–20 g/10 min.
• ABS – acrylonitrile-butadiene-styrene copolymer combining rigidity with impact resistance; ideal for electronics and automotive interiors.
• PC (polycarbonate) – amorphous transparent polymer with impact resistance, requires drying 120°C/4 h; processing temperature 280–320°C.
• PA6 / PA66 – engineering polyamides, hygroscopic; require drying and controlled cooling, often glass fiber reinforced (PA6 GF30).
• PBT / PET – engineering polyesters used in electrical connectors; feature high dimensional stability.
• POM (polyoxymethylene) – polyacetal with low friction, preferred for precision mechanics; requires rapid cooling.
• PEEK / PAEK – high-temperature polymers for aerospace and medical applications; mold temperatures 160–190°C.
• LSR (liquid silicone rubber) – liquid silicone injected via 1:1 metering systems, cured in heated molds.
• TPE / TPU – thermoplastic elastomers with rubber-like flexibility; key factors are substrate compatibility and melt temperature.
• Masterbatch – concentrated color or functional additive, dosed 1–5% into base resin.
• Compound – polymer blend with additives (fibers, powders, stabilizers) prepared by a compounder.
• Regrind / regranulate – in-house production scrap grind, often blended with virgin material at 5–30% ratios.
• PCR (post-consumer recycled) – post-consumer waste regrind requiring filtration and odor control; increasingly an OEM tender requirement.
• PIR (post-industrial recycled) – post-production scrap material with better uniformity, used in technical components.
• MFI/MFR flow index – material volume flowing through a capillary in 10 min under specified conditions; affects screw selection and injection speed.
• UV stabilizers, HALS, antioxidants – additives protecting polymers from degradation; require OEM specification.

Machines, components, and peripherals

A modern injection molding cell is an integrated ecosystem of the injection molding machine, mold, and automation. Key terms:

• Hydraulic injection molding machine – classic design with high clamping force and excellent flexibility; requires a hydraulic system and oil cooling.
• All-electric injection molding machine – servo drives for injection, clamping, and ejection axes, offering low energy consumption and high repeatability.
• Hybrid injection molding machine – combines hydraulics with electric drives for fast axes; ideal for thin-wall parts.
• Sequential valve gate – hot runner system component with electric or pneumatic control, enabling cavity fill sequence management.
• Barrier screw – screw geometry that boosts melt homogenization and productivity; matched to specific materials.
• Two-stage plasticizing unit – setup with separate extruder for MuCell, metal powder injection molding (MIM), or regrind processing.
• Linear / Cartesian robot – handles part and runner removal, pick-and-place operations, IML, or assembly.
• Collaborative robot (cobot) – flexible arm for assembly tasks and quality checks near the operator.
• 2D/3D vision system – camera for defect inspection, insert positioning, and IML completeness verification.
• Thermostat / chiller – maintains mold and cooling circuit temperatures; parameterized by flow rate (l/min) and ΔT.
• Desiccant dryer – dries hygroscopic polymers (PA, PC, PBT) to a dew point of -40°C.
• Vacuum loader – transports pellets to hoppers, often with dust separation.
• Low-speed granulator – on-machine runner recycling; minimizes material degradation.
• Molds with H13/1.2344 steel – standard tool steels for production runs; require proper hardness and heat treatment.
• Mold sensor mounting points – ports for pressure, temperature, and strain sensors, integrating with Kistler and Priamus systems.

Process parameters and quality control

Optimizing parameters requires knowledge of both machine settings and efficiency metrics:

• Injection pressure (injection pressure) – value in bar/MPa that determines fill speed; monitored in real time via the process curve.
• Injection speed – mm/s or cm³/s; controls the flow front, especially for thin-wall parts.
• Cylinder and heating zone temperatures – temperature profiles matched to the polymer, typically 3–5 s zones.
• Mold temperature – managed by thermostats; affects gloss, shrinkage, and structure uniformity.
• Holding time (holding time) – pressure hold phase before cooling begins; too short causes sink marks.
• Mold open time – impacts takt time; must account for robot and ejector motion.
• End-of-fill detection (V/P switchover) – switchover point from speed to pressure control; based on screw position, time, or in-mold pressure sensors.
• In-mold pressure curve monitoring – cavity pressure profile for early defect detection.
• SPC (Statistical Process Control) – statistical process control using Xbar-R charts, Pp, and Ppk.
• Cp/Cpk – process capability indices; values ≥1.67 required in automotive for critical features.
• DOE (Design of Experiments) – designed experiments to define the process window and parameter interactions.
• OEE (Overall Equipment Effectiveness) – OEE = Availability × Performance × Quality; benchmark target >85% for injection cells.
• MTBF / MTTR – mean time between failures and mean time to repair; used in predictive maintenance programs.
• Traceability (full traceability) – links material batch to part number, mold, process parameters, and production timestamp.
• In-line part weighing system – weighs each part for real-time setpoint corrections.

Quality, standards, and documentation

Terms related to compliance and OEM audits:

• ISO 9001 – quality management system, foundation for most injection molding plants.
• IATF 16949 – automotive industry specification requiring APQP, PPAP, MSA, and continuous improvement processes.
• ISO 13485 – standard for medical devices covering IQ/OQ/PQ validations, sterility, and eDHR.
• GMP / GAMP 5 – good manufacturing practices and computer system validation in pharmaceuticals.
• APQP (Advanced Product Quality Planning) – product quality planning from design phase to serial production.
• PPAP (Production Part Approval Process) – documentation package approving parts for production; includes Control Plan and measurement results.
• FMEA (Failure Mode and Effects Analysis) – analysis of process and design failure modes and effects.
• MSA (Measurement System Analysis) – measurement system evaluation (Gage R&R study).
• Control Plan – dimensional and parameter control plan, linked to SPC charts.
• 8D Report – eight-discipline method for solving quality problems.
• Poka-Yoke – error-proofing solutions (mechanical, software, sensory).
• VDA 6.3 audit – German standard for production process assessment; covers injection cells.
• IQ/OQ/PQ validations – Installation Qualification, Operational Qualification, Performance Qualification required in medical applications.

Digitalization, Industry 4.0, and AI

Modern injection molding machines are part of digital ecosystems. Key terms:

• MES (Manufacturing Execution System) – real-time production monitoring system that collects data on cycles, downtime, and quality.
• MOM (Manufacturing Operations Management) – higher-level process management integrating MES with ERP.
• SCADA – line visualization and control system; in injection cells, gathers data from machine PLCs, robots, and chillers.
• OPC UA – communication standard enabling data exchange between the injection molding machine and higher-level systems.
• IIoT (Industrial Internet of Things) – network of sensors (mold temperature, vibrations, energy) publishing data to the cloud.
• Digital Twin – digital replica of the injection cell replicating process parameters and maintenance schedules.
• AI/ML in injection molding – models predicting defects, optimizing speed profiles, and suggesting setpoint corrections.
• Edge computing – machine-side data processing for millisecond reactions without network latency.
• AR/VR for service – augmented reality supporting operator training and remote Tederic service.
• OT cybersecurity – protection of PLC controllers, HMI interfaces, and industrial networks from attacks.
• Generative reporting – automatic generation of quality reports, downtime logs, and instructions from process data.

Sustainability and Recycling

More and more injection molding projects require full environmental transparency. Key terms:

• LCA (Life Cycle Assessment) – product life cycle analysis, covering CO₂ emissions from raw material to recycling.
• Carbon Footprint – greenhouse gas emissions attributed to a single molded part; reported in kg CO₂e.
• Circular Economy – designing products for disassembly, regranulation, and reuse.
• ISCC PLUS / GRS – certifications confirming recycled or biomass material origins (Mass Balance).
• Biopolymers PLA, PHA, PBS – bio-based materials, often requiring lower mold temperatures.
• Mechanical / Chemical Recycling – plastic recovery methods; chemical recycling involves depolymerization to monomers.
• Cycle Energy Consumption (kWh/kg) – energy use per kg of molded part; all-electric injection molding machines can drop below 0,3 kWh/kg.
• Heat Recovery – recovering heat from mold cooling circuits and hydraulic oil systems.
• Eco-Mode / Standby – software modes that reduce energy draw during production breaks.
• Mold Refurbishment – repairs and PVD/TiN coatings that extend toolife and reduce scrap.

Advanced Molding Technologies

The trend toward multi-material, lightweight components demands expertise in specialized processes:

• Multi-Component 2K/3K Injection Molding – molding multiple materials in one cycle; requires rotary, transfer, or index molds.
• Insert Molding / Overmolding – encapsulating metal parts, electronics, or textiles in polymer.
• IML / IMD (In-Mold Labeling/Decorating) – in-mold decoration and labeling using films or labels.
• GAIM (Gas-Assisted Injection Molding) – gas-assisted injection molding that creates hollow sections, reducing weight and sink marks.
• WAIM (Water-Assisted Injection Molding) – water-assisted injection molding for thick-walled tubes and heat exchangers.
• MuCell / Physical Foaming – injecting gas (nitrogen, CO₂) to create a microcellular structure and reduce weight by 5–15%.
• MIM / CIM (Metal/Ceramic Injection Molding) – injection molding of metal or ceramic powders with binder, followed by sintering.
• Micro Injection Molding – micro-injection of parts <50 mg, using 14–18 mm diameter screws.
• LSR Injection – high-precision process for liquid silicone rubber, requiring two-component dosing and heated molds.
• Injection-Compression Molding – combining injection and mold compression, used for optical parts and panels.
• Variotherm / Dynamic Mold Temperature Control – cyclic mold temperature changes for Class A surfaces and glossy reflectors.
• DFM/A (Design for Manufacturing/Assembly) – designing parts and molds for easy injection and minimal secondary operations.

Key Abbreviations and Acronyms

Most commonly used abbreviations in documentation, quotes, and audits:

• BoP – Bill of Process, description of production process standards.
• BOM – Bill of Materials, list of materials and components for the molded part.
• COQ – Cost of Quality, total quality costs (prevention + appraisal + failure).
• DFMEA/PFMEA – FMEA analysis for design (Design) and process (Process).
• DOE – Design of Experiments, planned process experimentation.
• ERP – Enterprise Resource Planning, financial and logistics system (SAP, Oracle).
• GR&R – Gauge Repeatability and Reproducibility, measurement system repeatability study.
• IoT/IIoT – Industrial Internet of Things for monitoring injection mold cavities.
• KPIs – key performance indicators: OEE, scrap rate, MTTR.
• LOB – Line of Balance, multi-product production planning.
• PFEP – Plan for Every Part, logistics plan for every component.
• PIR/PCR – types of recyclate (post-industrial/post-consumer recycled).
• PLM – Product Lifecycle Management, product documentation management system.
• QMS – Quality Management System, integrated quality management system.
• SMED – Single-Minute Exchange of Die, quick mold change methodology.
• TPM – Total Productive Maintenance, comprehensive maintenance program.

How to Use the Glossary in Practice

This injection molding terminology dictionary serves as a practical reference tool for all participants in the production process:

1. Troubleshooting Production Issues – quickly reference parameter and metric definitions to identify root causes of defects and process deviations.
2. Configuring New Processes – when launching new molds or materials, the glossary ensures consistent understanding of technical terminology across departments.
3. Training Operators and Technologists – standardized definitions facilitate knowledge transfer and reduce onboarding time for new employees.
4. Communication with Suppliers and Customers – uniform terminology eliminates misunderstandings in technical specifications and PPAP documentation.
5. Audits and Quality Documentation – precise definitions of metrics (Cp, Cpk, OEE) support preparation for IATF 16949 and ISO 13485 audits.

Regular use of the glossary builds technical culture within the organization and ensures consistency in process documentation across all production levels.

Summary

The "2025 Injection Molding Terms Dictionary" is a compendium combining process, material, and digital knowledge in one place. It serves as a practical reference tool for technologists, operators, quality engineers, and maintenance teams. Through standardized terminology, it facilitates communication between departments, streamlines training programs, and supports documentation compliant with IATF 16949 and ISO 13485 requirements. Regular updates with new technologies and industry standards help organizations keep pace with the dynamic evolution of the injection molding industry.