Reference
Manufacturing engineering glossary
85 terms used in plant setup, line design, automation, quality and material handling — defined the way they are actually used on an Indian shop floor, not the way a textbook defines them.
Glossary
Line design and flow
Takt time
The rate at which one unit must be completed to meet customer demand: available production time per day divided by units required per day. Takt is set by demand, not by the line.
Cycle time
The time a station actually takes to complete its work and pass the unit on. The line's cycle time is that of its slowest station.
Work content
The total of all manual and machine time required to build one unit, across every operation, before it is divided into stations.
Line balancing
Allocating work content across stations so that each is loaded as evenly as possible and none exceeds the design cycle time.
Balance efficiency
Work content divided by (number of stations x design cycle time). A measure of how much station time is actually productive.
Bottleneck
The station or resource whose capacity limits the output of the whole line. Improving anything else changes nothing until the bottleneck moves.
Buffer
Deliberate storage between operations that decouples them, so a short stoppage at one station does not immediately starve or block its neighbours.
WIP (work in progress)
Units that have entered the line but not yet been completed. High WIP hides problems and ties up cash; too little makes the line fragile.
Standard work
The documented, repeatable sequence, timing and inventory for an operation. The baseline against which any improvement is measured.
Yamazumi chart
A stacked bar chart of work content per station against takt, used to see at a glance where a line is unbalanced.
Spaghetti diagram
A drawing of the actual path a person or part travels through a layout, used to expose wasted movement.
SMED (single-minute exchange of die)
A method for cutting changeover time by converting internal steps, which need the machine stopped, into external steps done while it runs.
Changeover time
The elapsed time from the last good part of one variant to the first good part of the next, at full rate.
One-piece flow
Moving units through the process one at a time rather than in batches, so problems surface immediately and WIP stays low.
Pull system
Producing only what the downstream process has consumed, signalled by kanban or an equivalent, instead of pushing to a forecast.
Kanban
A signal — card, container, or electronic — that authorises replenishment of a specific part in a specific quantity.
Cell layout
Machines and stations arranged by the sequence of a product family rather than by machine type, usually U-shaped to shorten operator travel.
Glossary
Machines and automation
SPM (special purpose machine)
A machine designed and built for one specific operation or family of parts, rather than a general-purpose machine adapted to it.
Semi-automatic station
The operator loads and unloads; the machine performs the operation and monitors it. The common middle ground on Indian assembly lines.
Pick and place unit
A two- or three-axis mechanism that transfers a part between fixed positions on a fixed cycle. Cheaper and faster than a robot where the motion never changes.
Robot cell
A robot with its tooling, fixturing, guarding and safety system, integrated as one unit. The robot is usually the smallest part of the cost.
End effector
The tooling at the robot's wrist — gripper, weld gun, dispenser, nutrunner. Usually the item that decides whether the cell works.
PLC (programmable logic controller)
The industrial controller that runs machine and line logic. Its make and generation largely determine spares availability and who can service the machine.
HMI (human machine interface)
The operator's screen and control panel. Good HMI design shows the operator what to do next and what went wrong, not just what the machine is doing.
Servo drive
A closed-loop drive that controls a motor's position, speed and torque, used where motion must be accurate and repeatable.
VFD (variable frequency drive)
A drive that varies an AC motor's speed. Common on conveyors, pumps and fans, and usually the cheapest energy saving on an old machine.
Pneumatics
Compressed-air actuation. Cheap and fast for fixed-stroke motion, but compressed air is expensive to produce, so leaks and continuous vacuum cost real money.
Retrofit
Replacing a machine's controls, drives, sensors or safety system while keeping its mechanical base. Viable only when the mechanics are still sound.
SCADA
Supervisory software that collects and displays data from multiple machines or lines, typically for monitoring and reporting rather than machine control.
MES (manufacturing execution system)
Software that manages production orders, routing, traceability and performance data between the ERP and the shop floor.
OEE (overall equipment effectiveness)
Availability x performance x quality, expressed as a percentage. Useful for trend and loss analysis; misleading when compared between different plants.
Digital twin
A simulation model of a line or machine used to test layout, throughput and logic before the equipment is built.
Glossary
Quality, measurement and error-proofing
Poka-yoke
Error-proofing. A design or device that makes an error impossible, or that stops the operation the moment one occurs, at the station that caused it.
Andon
A visual and audible signal that calls attention to a problem at a station, and the discipline of responding to it within a defined time.
FMEA (failure mode and effects analysis)
A structured review of how a process or design can fail, how bad each failure would be, how likely it is, and how it would be detected.
Control plan
The document listing what is controlled at each process step, how it is measured, at what frequency, and what to do when it is out of specification.
PPAP (production part approval process)
The evidence package a customer requires before approving a part for series supply, including capability studies and measurement system analysis.
Cp and Cpk
Process capability indices. Cp compares the spread of the process to the tolerance; Cpk also accounts for how far the process is off-centre.
GR&R (gauge repeatability and reproducibility)
A study of how much of the observed variation comes from the measurement system rather than the parts.
SPC (statistical process control)
Charting a process characteristic over time to distinguish normal variation from a real change that needs action.
Checking fixture
A purpose-built gauge that holds a part in its functional datums so features can be checked quickly and repeatably on the shop floor.
Datum
A reference feature from which dimensions are measured. Fixtures and gauges must locate on the same datums as the drawing, or measurements will not agree.
GD&T (geometric dimensioning and tolerancing)
A symbolic language for specifying form, orientation and location tolerances relative to datums, rather than by dimensions alone.
Torque-angle monitoring
Recording both torque and rotation angle during tightening, and accepting only results inside a defined window. Catches cross-threading and stripped threads that torque alone misses.
Force-displacement monitoring
Recording the force-versus-distance signature of a press or insertion operation and comparing it to an accept envelope.
Leak test
Verifying sealing integrity, usually by pressure decay or mass flow, against a calibrated master leak. Temperature and dwell control decide repeatability.
EOL (end of line) test
The final functional test before despatch, which confirms the assembled product performs as specified and records the result.
Traceability
The recorded link between a finished unit and the components, process results, station, time and operator that produced it.
Containment
The immediate action taken when a defect escapes — identifying, isolating and sorting the suspect population until a permanent fix is proven.
Master part
A known-good or known-bad sample used to verify that a gauge, sensor or test station is still detecting what it is supposed to detect.
Glossary
Material handling and storage
Belt conveyor
A continuous belt carrying products. Suits light, small or irregular items with no flat base; products cannot accumulate without slipping.
Roller conveyor
Products ride on rollers, driven or gravity. Needs a flat, rigid base of adequate length, and allows accumulation when zoned.
Accumulation
Allowing products to queue on the conveyor without pressing on each other, so a stopped station does not stop the whole line.
Free-flow conveyor
A pallet conveyor whose chain slips beneath stopped pallets, so pallets can queue and be located precisely at each station.
Pallet (assembly)
The carrier that a product rides on through a line, providing consistent locating. Not to be confused with a storage pallet.
Slat conveyor
A chain-driven conveyor with a continuous slat surface, used for heavy, hot or dirty products and where operators walk alongside.
Power-and-free
An overhead conveyor in which carriers can be disengaged from the drive chain to stop, accumulate or divert while the chain keeps running.
AGV / AMR
Automated guided vehicle (follows a fixed path) or autonomous mobile robot (navigates dynamically). Both replace manual transport between areas.
Stillage
A rigid steel container, usually stackable, for storing and moving parts between operations or to the customer.
Returnable packaging
Reusable containers, dunnage and trolleys that cycle between supplier and customer, replacing single-use packaging.
Flow rack
Gravity-fed shelving that presents parts at the point of use and replenishes from the rear, so the operator never handles empty containers.
Tugger train
A towing vehicle with trolleys that delivers parts to the line on a fixed route and timetable, replacing individual forklift trips.
Kitting
Assembling all the parts for one unit into a kit before it reaches the line, so the operator picks from one place instead of many.
Selective pallet racking
The standard adjustable beam racking that gives direct access to every pallet. Simple and flexible, at the cost of floor area.
Lifting and tilting table
A powered table that raises and tips a container or assembly to a comfortable working height and angle, reducing reach and bending.
Glossary
Safety and compliance
Risk assessment
The structured identification of hazards and evaluation of risk that determines what safeguarding a machine actually needs, under ISO 12100.
Fixed guard
A barrier held in place by fixings that require a tool to remove. The first choice wherever routine access is not needed.
Interlocked guard
A movable guard whose opening commands a stop, optionally with guard locking so it cannot open until motion has ceased.
Light curtain
An optoelectronic device that detects a person entering a hazard zone and commands a stop. Its mounting distance depends on total stopping time.
Performance level (PL)
The reliability classification, a to e, that a safety-related control function must achieve under ISO 13849-1, derived from the risk assessment.
Stopping time
The total time from a stop signal to the hazard ceasing — device, controls, valves and machine run-down. Must be measured, not assumed.
LOTO (lock-out tag-out)
The procedure and hardware that isolate and lock off every energy source, including stored pneumatic and gravity energy, before maintenance.
Emergency stop
A manually operated command to stop the machine as quickly as safely possible. A complement to safeguarding, never a substitute for it.
Glossary
Projects and commissioning
Greenfield
A new facility built on an undeveloped site, with full freedom of layout and a longer schedule.
Brownfield
Expansion or modification within an existing facility, constrained by what is already there and by production that must continue.
Turnkey
A single supplier takes responsibility for design, build, installation and commissioning, handing over a working installation.
Design freeze
The point at which the design is agreed and signed off, after which changes carry cost and schedule impact. The most important date in the project.
FAT (factory acceptance test)
Testing the equipment at the supplier's works, ideally with your parts, before despatch. The cheapest place to find a problem.
SAT (site acceptance test)
Repeating the acceptance criteria on your floor, under production conditions, after installation.
Commissioning
Bringing the equipment from installed to producing good parts at rate — connecting utilities, tuning, trial running and correcting.
SOP (start of production)
The date series production begins. Everything in a plant project schedules backwards from it.
Ramp-up
The planned climb from first production to rated output, during which yield, cycle time and reliability all still improve.
Utilities schedule
The document listing every connection each machine needs — power, air, water, exhaust, drainage — with loads and positions. Late utilities data is a common cause of delay.
Layout (plant layout)
The arrangement of processes, storage, services and movement routes on the floor. Decided before the building, not after.
Scope boundary
The written line between what the supplier provides and what the customer provides. Most disputes on equipment projects start here.
Go deeper
Guides that use these terms
Most of the vocabulary above shows up in our practical guides: assembly line design, error-proofing, machine guarding, choosing a conveyor and plant setup. The takt time calculator puts numbers against the first four.
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