Manufacturing Operations Glossary
Plain-English definitions of the OEE, lean and maintenance terms that run a factory - each linked to the tool or guide that puts it to work.
A
5S
A workplace-organisation method - Sort, Set in order, Shine, Standardise, Sustain - that makes problems and waste visible.
5 Whys
A root-cause technique: ask "why" repeatedly (about five times) until you reach the underlying cause rather than a symptom.
Andon
A visual (and sometimes audible) signal system that flags a problem or stop on the line so it gets attention immediately.
Availability
An OEE factor: run time ÷ planned production time - the share of planned time the equipment was actually running. Reduced by breakdowns and setup.
B
Bottleneck
The slowest step in a process; it sets the maximum throughput of the whole line, so improvements elsewhere don't help until the bottleneck moves.
C
Changeover
Switching a machine or line from one product or format to the next. Long changeovers cut into Availability - see SMED.
CMMS
Computerised Maintenance Management System - software to manage work orders, preventive maintenance schedules, spare parts and asset history.
Cycle time
The actual time taken to produce one unit. To meet demand, cycle time must be at or below takt time.
D
Downtime
Any time production is stopped, planned (changeovers, maintenance) or unplanned (breakdowns). Unplanned downtime is the costly kind.
F
Fishbone (Ishikawa) diagram
A cause-and-effect diagram that groups potential causes of a problem into categories (e.g. machine, method, material, manpower) to guide root-cause analysis.
First Pass Yield (FPY)
The share of units produced correctly the first time, with no rework or scrap. A core input to the Quality factor of OEE.
H
Hidden factory
The production capacity quietly lost to small, frequent, unrecorded stops and speed losses - invisible in reports but often 5–20% of output.
J
JIT (Just-in-Time)
Producing and delivering only what's needed, when it's needed, to minimise inventory - which also makes the line less tolerant of downtime.
K
Kaizen
Continuous, incremental improvement driven by the people who do the work.
Kanban
A pull-based signalling system that controls work-in-process and flow by only producing to replace what's consumed.
L
Lead time
The total elapsed time from starting a unit to finishing it, including all waiting - broader than cycle time.
Lean
A methodology focused on maximising customer value while systematically eliminating waste.
M
MES
Manufacturing Execution System - software that tracks and controls production as it happens on the floor.
Micro-stop
A brief stoppage, usually under five minutes, cleared by the operator and rarely logged individually. The main driver of the hidden factory.
MOM
Manufacturing Operations Management - a broader platform layer that includes MES plus quality, maintenance and performance management.
MTBF
Mean Time Between Failures = total operating time ÷ number of failures. Higher means the asset runs longer between failures.
MTTR
Mean Time To Repair = total repair time ÷ number of failures. Lower means failures are fixed faster.
O
OEE
Overall Equipment Effectiveness = Availability × Performance × Quality. The single percentage for how much planned time is truly productive.
OOE
Overall Operations Effectiveness - the same A × P × Q formula, but measured against all scheduled/staffed time.
P
Performance
An OEE factor: (ideal cycle time × total count) ÷ run time - actual speed versus the ideal. Reduced by micro-stops and slow running.
PLC
Programmable Logic Controller - the industrial computer that controls a machine; the source of the most reliable, automatic OEE and stop data.
Poka-yoke
Mistake-proofing - designing a process so errors are hard or impossible to make.
Predictive maintenance (PdM)
Maintenance triggered by condition data or a failure prediction, so work happens just before failure rather than on a fixed schedule.
Preventive maintenance (PM)
Maintenance performed on a planned schedule to reduce the chance of failure.
Q
Quality (OEE factor)
Good units ÷ total units produced. Rework counts as a defect, not a good unit.
R
Reactive maintenance
Fixing equipment only after it fails ("run to failure") - the most disruptive and often most expensive approach.
Root cause analysis (RCA)
A structured method to find the underlying cause of a problem so it can be eliminated, not just patched. Common tools: 5 Whys, Fishbone.
S
Scrap
Product rejected and discarded because it doesn't meet specification - a direct quality loss.
Six big losses
The six categories every OEE loss falls into: breakdowns and setup (Availability); minor stops and reduced speed (Performance); defects and startup yield (Quality).
SMED
Single-Minute Exchange of Die - a method to cut changeover time to single-digit minutes, recovering availability.
SPC
Statistical Process Control - using control charts and statistics to keep a process stable and catch drift before it makes defects.
T
Takt time
The pace demand requires: available production time ÷ customer demand. The heartbeat a line is balanced around.
TEEP
Total Effective Equipment Performance = OEE × Utilization, measured against all 168 calendar hours. Reveals idle, sellable capacity.
Throughput
The rate at which a system produces good output.
TPM
Total Productive Maintenance - an approach that involves operators in routine maintenance to maximise equipment effectiveness; the origin of the six big losses.
U
Utilization
Scheduled production time ÷ all calendar time. The factor that turns OEE into TEEP.
W
WIP (Work in Process)
Partly finished goods between process steps. High WIP hides problems and ties up cash.
Y
Yield
The share of input material or units converted into good, sellable output.