Industrial Engineering & Manufacturing Glossary

Plain-English definitions for 120+ industrial engineering, manufacturing, lean, and Six Sigma terms — each with its own in-depth page and links to guides, calculators, and templates.

120+ terms
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5 Whys Read →
A root cause technique where you ask "why?" repeatedly until you reach the fundamental cause of a problem.
QualityLean
5S (Sort, Set in Order, Shine, Standardize, Sustain) Read →
A five-step workplace organization method that creates clean, orderly environments where abnormalities are immediately visible.
Lean
8 Wastes (DOWNTIME) Read →
The eight categories of waste lean targets: Defects, Overproduction, Waiting, Non-utilized talent, Transportation, Inventory, Motion, Extra processing.
Lean
8D (Eight Disciplines) Read →
A structured eight-step problem-solving and corrective-action method, widely used in automotive supplier quality.
Quality
A
A3 Thinking (A3 Report) Read →
A structured problem-solving approach that fits the whole problem, analysis, and countermeasures on a single A3-size sheet.
Lean
ABC Analysis (Pareto Inventory Classification) Read →
An inventory categorization that ranks items into A, B, and C classes by value so control effort is focused where it matters.
Supply Chain
ADKAR (Awareness, Desire, Knowledge, Ability, Reinforcement) Read →
A change-management model that focuses on the individual stages a person moves through during organizational change.
Project ManagementLean
Andon Read →
A visual signal — usually a light or board — that alerts the team to an abnormal condition on the line so it can be addressed immediately.
LeanQuality
Autonomous Maintenance (Jishu Hozen) Read →
The TPM pillar in which operators take ownership of basic equipment care — cleaning, inspecting, lubricating, and detecting abnormalities.
Maintenance
Availability Read →
The percentage of planned production time that equipment is actually running — one of the three OEE factors.
Maintenance
B
Batch Size (Lot Size) Read →
The number of units produced between changeovers — smaller batches cut lead time and WIP but require more setups.
Flow
Bill of Materials (BOM) Read →
A hierarchical list of all components, sub-assemblies, and raw materials needed to build a product.
Systems & TechSupply Chain
Bottleneck (Constraint) Read →
The process step with the lowest capacity, which sets the maximum throughput of the entire system.
Flow
Bullwhip Effect Read →
The amplification of demand swings as orders travel upstream through a supply chain.
Supply ChainFlow
C
Capacity Planning Read →
Determining the production capacity an operation needs to meet changing demand across short, medium, and long horizons.
Supply ChainFlow
Capacity Utilization Read →
Actual output as a percentage of maximum possible output — high utilization sounds good but drives up queue time.
Flow
Cellular Manufacturing (Work Cells) Read →
Arranging equipment and workstations into a compact cell (often U-shaped) that processes a family of similar products in flow.
LeanFlow
Changeover (Setup) Read →
The time to switch production from one product to the next, including cleanup, tooling change, adjustment, and first-article validation.
Flow
Continuous Flow Read →
Producing and moving one unit at a time through a sequence of steps with no stops or batches between them.
FlowLean
Continuous Improvement (CI / Kaizen) Read →
The ongoing, organization-wide effort to improve products, services, and processes through small incremental changes.
Lean
Control Chart (Shewhart Chart) Read →
A time-series chart with statistical control limits used to distinguish normal variation from special-cause variation.
Six SigmaQuality
CONWIP (Constant Work In Process) Read →
A pull system that caps the total work-in-process in a line, releasing new work only as finished work exits.
Flow
Cost of Quality (COQ) Read →
The total cost of achieving quality (prevention + appraisal) plus the cost of failing to (internal + external failure).
Quality
Critical Chain (CCPM) Read →
A project scheduling method that accounts for resource constraints and protects the plan with aggregated buffers.
Project Management
Critical Path Method (CPM) Read →
A scheduling technique that finds the longest sequence of dependent tasks, which determines the shortest possible project duration.
Project Management
Cycle Time Read →
The time to complete one unit of work from start to finish at a process — distinct from takt time and lead time.
Flow
D
Design of Experiments (DOE) Read →
A statistical method for efficiently testing multiple factors at once to find which inputs drive an output and how they interact.
Six Sigma
Discrete-Event Simulation (Process Simulation) Read →
Modeling a process as a sequence of events to predict performance, test changes, and find bottlenecks before building them.
Work MeasurementSystems & Tech
DMAIC (Define, Measure, Analyze, Improve, Control) Read →
The five-phase data-driven improvement cycle at the heart of Six Sigma for improving existing processes.
Six Sigma
Downtime Read →
Any period when equipment is not producing during planned production time, whether planned or unplanned.
MaintenanceFlow
DPMO (Defects Per Million Opportunities) Read →
A normalized defect metric that allows fair comparison of quality across processes of different complexity.
Six Sigma
Drum-Buffer-Rope (DBR) Read →
A Theory of Constraints scheduling method that paces the whole plant to the bottleneck and protects it with a time buffer.
Flow
E
Earned Value Management (EVM) Read →
A project-control technique that integrates scope, schedule, and cost to measure performance and forecast outcomes.
Project Management
Economic Order Quantity (EOQ) Read →
The order quantity that minimizes the combined cost of ordering and holding inventory.
Supply Chain
Ergonomics (Human Factors) Read →
Designing work, tools, and workstations to fit human capabilities and limitations, reducing injury and fatigue.
SafetyWork Measurement
ERP (Enterprise Resource Planning) Read →
Integrated software that manages core business processes — finance, inventory, planning, procurement — on a shared database.
Systems & Tech
F
FIFO (First-In, First-Out) Read →
A sequencing discipline ensuring the oldest item is processed or shipped first, preserving order and freshness.
FlowSupply Chain
First Pass Yield (FPY) Read →
The percentage of units that pass through a process correctly the first time, with no rework or repair.
Quality
Fishbone Diagram (Ishikawa / Cause-and-Effect Diagram) Read →
A cause-and-effect diagram that organizes potential causes of a problem into categories shaped like a fish skeleton.
Quality
Flow Read →
The smooth, uninterrupted movement of material and information through a value stream with minimal stops or queues.
LeanFlow
FMEA (Failure Mode and Effects Analysis) Read →
A structured method to identify potential failure modes, rate their risk, and prioritize preventive actions.
Quality
G
Gage R&R (Gauge Repeatability & Reproducibility) Read →
A study that quantifies how much of observed variation comes from the measurement system rather than the process.
Six SigmaQuality
Gantt Chart Read →
A horizontal bar chart that shows project tasks against a timeline, with their durations, dependencies, and progress.
Project Management
Gemba (The Real Place) Read →
The actual place where work happens — the shop floor — where leaders go to observe reality firsthand.
Lean
Genchi Genbutsu (Go and See) Read →
The Toyota principle of going to the source to see for yourself before making a decision.
Lean
Group Technology Read →
A method of grouping similar parts into families to exploit their similarities in design and manufacturing.
Work MeasurementLean
H
Heijunka (Production Leveling) Read →
Leveling the volume and mix of production over time to reduce unevenness and enable smooth flow.
LeanFlow
Hoshin Kanri (Policy Deployment) Read →
A strategic planning process that aligns goals and actions from the executive level down to the shop floor.
Lean
I
IIoT (Industrial Internet of Things) Read →
A network of connected sensors and machines that stream real-time data from the factory floor for monitoring and analytics.
Systems & Tech
Industry 4.0 (The Fourth Industrial Revolution) Read →
The digital transformation of manufacturing through connectivity, data, automation, and smart systems.
Systems & Tech
Inventory Read →
Raw materials, work-in-process, and finished goods held in the system — one of the eight wastes when excessive.
Supply ChainFlow
J
Jidoka (Autonomation) Read →
"Automation with a human touch" — machines detect abnormalities and stop automatically to prevent defects.
LeanQuality
Just-in-Time (JIT) Read →
Producing and delivering exactly what is needed, when it is needed, in the amount needed.
LeanFlow
K
Kaizen (Change for Better) Read →
Continuous, incremental improvement involving everyone — from daily small ideas to structured multi-day events.
Lean
Kanban Read →
A visual signaling system that triggers production or replenishment based on actual consumption rather than forecasts.
LeanFlow
Kingman's Equation (VUT Equation) Read →
A queueing formula showing wait time rises sharply with utilization and variability.
Flow
KPI (Key Performance Indicator) Read →
A measurable value that shows how effectively an operation is achieving its key objectives.
Lean
L
Lead Time Read →
The total elapsed time from order (or raw material) to delivery (or finished product), including all waiting.
Flow
Lean Manufacturing (Toyota Production System) Read →
A systematic approach to maximizing customer value by relentlessly eliminating waste through continuous improvement.
Lean
Lean Six Sigma Read →
A methodology combining lean's focus on flow and waste with Six Sigma's focus on reducing variation and defects.
Six SigmaLean
Learning Curve (Experience Curve) Read →
The predictable reduction in labor hours per unit as cumulative production volume increases.
Work Measurement
Line Balancing Read →
Distributing work evenly across stations so each cycle time is at or below takt, minimizing idle time and bottlenecks.
FlowWork Measurement
Line Efficiency (Balance Efficiency) Read →
The ratio of total value-added work time to total available station time across a line — a measure of how well it is balanced.
Flow
Little's Law Read →
A fundamental relationship: WIP = Throughput × Lead Time, explaining why cutting WIP shortens lead time.
Flow
M
MES (Manufacturing Execution System) Read →
Software that manages and tracks production execution on the shop floor in real time, bridging ERP and the machines.
Systems & Tech
Milk Run Read →
A scheduled route that picks up or delivers material in small quantities from multiple points on a fixed cycle.
Supply ChainFlow
Monte Carlo Simulation Read →
A technique that runs thousands of randomized trials to produce a probability distribution of outcomes.
Project ManagementWork Measurement
MRP (Material Requirements Planning) Read →
A planning logic that explodes a production schedule through the BOM to calculate what to order or make, and when.
Systems & TechSupply Chain
MTBF (Mean Time Between Failures) Read →
The average operating time between equipment breakdowns — a key reliability metric where higher is better.
Maintenance
MTTR (Mean Time To Repair) Read →
The average time to restore equipment to operation after a failure — lower is better.
Maintenance
Muda (Waste) Read →
Any activity that consumes resources but creates no value for the customer.
Lean
Mura (Unevenness) Read →
Variation and irregularity in workload or flow that creates waste and overburden.
Lean
Muri (Overburden) Read →
Unreasonable strain on people or equipment caused by poor design or uneven demand.
LeanSafety
O
OEE (Overall Equipment Effectiveness) Read →
The gold-standard equipment metric: Availability × Performance × Quality. World-class is 85%+.
MaintenanceFlow
One-Piece Flow (Single-Piece Flow) Read →
Moving a single unit through each step at a time, with no batching or queues between operations.
FlowLean
Operating Rhythm (Management Operating System) Read →
The structured cadence of meetings, reviews, and walks that keeps an operation aligned and responsive.
Lean
P
Pareto Analysis (80/20 Rule) Read →
A technique that focuses effort on the "vital few" causes that account for the majority of a problem.
Quality
PDCA (Plan-Do-Check-Act / Deming Cycle) Read →
A four-step iterative improvement cycle: Plan a change, Do it small, Check the results, Act to standardize or adjust.
Lean
PERT (Program Evaluation and Review Technique) Read →
A scheduling method that uses optimistic, likely, and pessimistic estimates to model task duration uncertainty.
Project Management
Poka-Yoke (Mistake-Proofing) Read →
Any device or design that prevents an error from being made or from becoming a defect.
Quality
Predictive Maintenance (PdM / Condition-Based Maintenance) Read →
Using condition-monitoring data to predict and prevent failures just before they would occur.
MaintenanceSystems & Tech
Preventive Maintenance (PM / Planned Maintenance) Read →
Scheduled, time- or usage-based maintenance performed to prevent failures before they happen.
Maintenance
Process Capability (Cp / Cpk) Read →
Indices (Cp, Cpk) that compare the spread and centering of a process to its specification limits.
Six SigmaQuality
Pull System Read →
Production triggered by actual downstream consumption rather than forecasts — work is pulled by demand.
LeanFlow
Push System Read →
Production driven by forecasts and schedules, pushing work downstream regardless of actual demand.
Flow
Q
Quality Function Deployment (QFD / House of Quality) Read →
A structured method to translate customer requirements into specific engineering and process characteristics.
Quality
R
Reorder Point (ROP) Read →
The inventory level at which a replenishment order should be placed to avoid a stockout during the lead time.
Supply Chain
Resource Leveling Read →
Adjusting a project schedule to smooth resource demand and resolve over-allocations.
Project ManagementFlow
Rolled Throughput Yield (RTY) Read →
The probability a unit passes through every step of a process defect-free — the product of each step's first pass yield.
Six SigmaQuality
Root Cause Corrective Action (RCCA / RCA) Read →
The disciplined process of finding a problem's fundamental cause and implementing a permanent fix.
Quality
S
Safety (Workplace Safety) Read →
The systems, behaviors, and culture that protect workers from injury and illness — always the first priority.
Safety
Safety Stock (Buffer Stock) Read →
Extra inventory held as a buffer against demand and supply variability to protect service level.
Supply ChainFlow
Schedule Adherence (Plan Attainment) Read →
The percentage of the planned production that was actually completed on time and in the right sequence.
Flow
Scrap (Waste / Reject) Read →
Material or product that fails quality requirements and cannot be reworked, representing pure loss.
Quality
Sigma Level (Process Sigma) Read →
A measure of process capability expressed in standard deviations between the mean and the nearest spec limit.
Six Sigma
Six Sigma Read →
A data-driven methodology for reducing variation and defects to no more than 3.4 per million opportunities.
Six Sigma
SMED (Single-Minute Exchange of Die) Read →
A systematic method for cutting changeover time to single-digit minutes by converting internal setup to external.
Lean
Spaghetti Diagram Read →
A visual tracing of the physical path of a product, person, or material to expose wasted motion and transport.
LeanFlow
SPC (Statistical Process Control) Read →
Using control charts to monitor a process and distinguish normal variation from special-cause signals requiring action.
Six SigmaQuality
Standard Operating Procedure (SOP) Read →
A documented, step-by-step instruction for consistently performing a routine task or process.
QualityLean
Standard Time Read →
The time a qualified, trained worker should take to complete a task at a normal pace, including allowances.
Work Measurement
Standard Work (Standardized Work) Read →
The documented current best method for a task, tied to takt time, sequence, and standard WIP — the baseline for improvement.
Lean
Supermarket (Lean Supermarket) Read →
A controlled inventory store of standard quantities that a downstream process pulls from and upstream replenishes.
LeanFlow
T
Takt Time Read →
The rate of customer demand — available production time divided by demand — that sets the pace production must match.
LeanFlow
Theory of Constraints (TOC) Read →
A management philosophy that every system has one constraint limiting it, and improvement means managing that constraint.
Flow
Throughput Read →
The rate at which a system produces finished, sellable output — ultimately limited by the bottleneck.
Flow
Tier Meetings (Tiered Daily Management (T1–T4)) Read →
A layered system of short daily meetings that escalate problems up and cascade actions down the organization.
Lean
Time Study (Stopwatch Time Study) Read →
Direct observation and timing of a task, broken into elements, to establish a standard time.
Work Measurement
Toyota Kata (Improvement Kata & Coaching Kata) Read →
A structured routine for developing a scientific, continuous-improvement mindset through deliberate daily practice.
Lean
TPM (Total Productive Maintenance) Read →
A system for maximizing equipment effectiveness through operator involvement and proactive maintenance, targeting zero breakdowns.
Maintenance
TRIR (Total Recordable Incident Rate) Read →
The number of OSHA-recordable injuries per 200,000 hours worked — the standard safety benchmark.
Safety
TWI (Training Within Industry) Read →
A set of structured supervisor skills — Job Instruction, Job Methods, and Job Relations — for training and improving work.
Lean
V
Value Stream Read →
All the activities — value-adding and not — required to bring a product from raw material to the customer.
Lean
Value Stream Mapping (VSM) Read →
A pencil-and-paper method for visualizing material and information flow to expose waste and design a better future state.
Lean
Value-Added (VA vs Non-Value-Added) Read →
Activity that transforms a product in a way the customer is willing to pay for — everything else is waste or necessary non-value-added.
Lean
Visual Management (Visual Controls) Read →
Making the status of work, performance, and standards instantly visible so anyone can understand the situation at a glance.
Lean
W
Water Spider (Mizusumashi) Read →
A dedicated logistics worker who replenishes line-side materials on a timed route so operators never leave their station.
LeanFlow
WIP (Work In Process) Read →
Inventory that has entered production but is not yet finished — the lever that controls lead time via Little's Law.
Flow
Work Breakdown Structure (WBS) Read →
A hierarchical decomposition of a project into progressively smaller, manageable deliverables and work packages.
Project Management
Work Sampling (Activity Sampling) Read →
A statistical technique that uses many random observations to estimate the proportion of time spent on each activity.
Work Measurement
Y
Yamazumi Chart (Work Balance Chart) Read →
A stacked-bar chart showing each operator or station's workload against takt time to guide line balancing.
FlowLean
Yokoten (Horizontal Deployment) Read →
The practice of systematically sharing and replicating improvements horizontally across teams, lines, and plants.
Lean

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