Hattatsu Glossary
Key terms of efficiency improvement tools in plain language: what each term means, how it is applied on the shop floor and the mistake companies make most often when implementing it. The glossary is written by Hattatsu Group experts based on their work at manufacturing sites.
Equipment Reliability (TPM)
TPM — Total Productive Maintenance
An equipment maintenance system in which operators do daily care (cleaning, lubrication, inspection) while the maintenance team handles planned and complex work. The goal is zero unplanned stops, defects and accidents.
Autonomous maintenance checklists, visual tags on equipment, a preventive maintenance schedule and downtime cause tracking are introduced. The result is measured through OEE and mean time between failures.
Treating TPM as the maintenance department’s job only. Without operators taking part, minor faults pile up until a breakdown.
OEE — Overall Equipment Effectiveness
The share of planned production time during which equipment produced good parts at its rated speed. It equals availability multiplied by performance and quality.
OEE = availability × performance × quality. Availability is actual run time divided by planned time, performance is actual output divided by possible output at rated speed, and quality is good units divided by all units produced. Calculation example: 0.80 × 0.85 × 0.95 ≈ 0.65, which means OEE of 65%.
Comparing OEE across work areas and plants as a ranking. Downtime is counted differently in each place, and the metric is mainly useful for finding the biggest losses on a specific machine.
Six Big Losses of Equipment
Six hidden causes that drag down overall equipment effectiveness (OEE):
- Breakdowns.
- Long changeovers and adjustments.
- Idling and minor stops (micro-stoppages).
- Running below rated speed.
- Defects during start-up and warm-up.
- Defects during the production run.
Teams keep a minute-by-minute log of downtime causes, manually or through SCADA/MES sensors. Once a week they build a Pareto chart of OEE losses, and the engineering team takes on the top cause.
Counting only a major half-day breakdown as downtime and ignoring hundreds of 30–60 second micro-stoppages that together eat up to 25% of shift output.
Jishu Hozen — Autonomous Maintenance
The first and key pillar of TPM: basic machine care (cleaning, lubrication, tightening, visual inspection) is handed over from the maintenance department to the machine operators themselves.
Teams create daily cleaning, inspection and lubrication (CIL) sheets that take 10–15 minutes per shift. Operators learn to spot a defect by sound, vibration and small leaks before the unit seizes.
Issuing an order that operators now clean the machines, with no training and no scheduled time at the start or end of the shift. Workers see it as unpaid extra work and stop doing it.
SMED — Quick Changeover
A method for reducing equipment changeover time developed by Shigeo Shingo. The goal is a changeover in single-digit minutes, that is, under 10 minutes.
The changeover is filmed and its steps are split into internal ones, which can only be done with the machine stopped, and external ones, which can be prepared in advance. As many steps as possible are moved to external, then fastening and adjustments are simplified. Changeover time counts in OEE as an availability loss.
Trying to shorten changeovers by buying new equipment. Most of the time usually goes into searching for tools, waiting for material and trial adjustments, and that is solved by organizing the work, with no capital investment.
MTBF and MTTR — Reliability and Maintainability
The two main indicators of a maintenance department:
- MTBF (Mean Time Between Failures): how many hours a machine runs between breakdowns on average.
- MTTR (Mean Time To Repair): how long, on average, mechanics and electricians take to find and fix a breakdown.
The maintenance team’s job is to raise MTBF by removing the root causes of failures and to cut MTTR by standardizing repairs, keeping critical spare parts in stock and training on-duty mechanics.
Judging the chief mechanic’s department by the number of replaced parts and completed repairs instead of by how long the equipment runs without failure.
Red Tagging in TPM
A way for operators and setters to flag machine defects themselves: every oil leak, play, exposed wire, cracked hose or missing bolt they find gets a standard tag.
The tag shows the date, the operator’s name and a description of the problem, and its stub goes into the maintenance plan. The tag is removed only after the defect is fixed and the supervisor has signed off.
Hanging hundreds of tags without assigning mechanics to fix the defects. Two weeks later the faded tags are just visual clutter.
CBM — Condition-Based Maintenance
Moving from calendar-based repairs to maintenance based on the actual condition of components: vibration analysis, thermal imaging of bearings, oil analysis and monitoring of electrical load.
Mechanics regularly walk the critical equipment with vibration meters and pyrometers and log the trends. A bearing is replaced at the first signs of raceway damage, not after it has fallen apart and seized the shaft.
Installing expensive vibration monitoring on old machines that lack even regular lubrication and coolant filtration.
Flow and Waste (TPS)
Lean Production
A production management system that organizes the entire flow from order to shipment so that every action that adds no value for the customer is removed. The goal is not to cut staff but to let the same team on the same equipment produce more, faster and with fewer defects.
Work starts with a value stream map (VSM) of one product family: all operations, the inventory between them and the lead time are recorded. Then the seven wastes are identified: overproduction, waiting, transportation, overprocessing, inventory, motion and defects. Changes are first tested on a pilot area and only then rolled out to the rest of the plant.
Rolling out tools from a checklist (5S, kanban, boards) without linking them to the bottleneck of the flow. The shop floor gets cleaner, but lead times and costs stay the same, and within six months everything slides back.
TPS — Toyota Production System
A production model developed at Toyota in the 1950s–1970s under Taiichi Ohno that became the foundation of Lean. It rests on two pillars: just-in-time and jidoka, which means built-in quality.
It serves as a reference when a company builds its own production system: stable processes and standardized work at the base, then flow and pull, stopping at abnormalities and kaizen as a daily practice. Each element is adapted to the type of production: high-volume, make-to-order or process industry.
Copying TPS word for word. Toyota’s tools grew out of high-volume assembly with levelled demand, and in a make-to-order plant they have to be redesigned, otherwise they create bureaucracy instead of flow.
The Three Ms: Muda, Muri, Mura
Three sources of operational inefficiency:
- Muda: waste, meaning activities that consume resources but create no value for the customer.
- Muri: overburden of people or equipment beyond their designed capacity.
- Mura: unevenness, meaning fluctuating volumes and an irregular pace of work.
Work on waste starts not with muda but with mura (levelling shift schedules) and muri (removing overburden). Hidden waste can only be cut reliably in a stable, even process.
Fighting only muda, for example by shortening workers’ walking routes, while ignoring the uneven supply of parts that leaves the shop idle half the day and rushing the other half.
The Seven Wastes
A classification of activities that add cost without creating value:
- Overproduction, the worst waste: making products earlier or in larger quantities than ordered.
- Waiting: idle time caused by late materials, a busy crane, missing tooling or pending approvals.
- Excess transportation: long routes for parts between workshops.
- Overprocessing: excessive precision or operations the customer does not pay for.
- Excess inventory: working capital frozen in warehouses and buffers between operations.
- Unnecessary motion: bending, searching for tools, operators walking around the machine.
- Defects and rework: the cost of fixing defects and disposing of scrap.
During a rapid shop-floor audit, Hattatsu Group experts record every metre of movement and every minute of the cycle and break the shift down into value-adding work and the seven wastes.
Confusing value-adding work with being busy. A worker who spends four hours a shift searching for tooling and shifting glass racks gets very tired but creates no value.
The Eighth Waste — Unused Employee Potential
The loss of people’s ideas, suggestions, skills and energy caused by an authoritarian management style and the lack of feedback channels.
Companies introduce a transparent process for kaizen ideas: a worker proposes an improvement to their own workstation and within 3–5 days gets the resources to implement it and recognition from colleagues.
Treating workers as just a pair of hands and demanding that they follow instructions with no say in how the work is done.
VSM — Value Stream Mapping
A tool that visualizes all material and information flows from the arrival of raw materials to the shipment of finished goods to the customer.
The project team walks the product’s path through the shop from the raw-material store to dispatch and measures processing time (cycle time), waiting time between operations, total lead time and work-in-progress. From this data they draw the current-state map, find the bottlenecks and design the future-state map.
Drawing the VSM in an office from standard routing sheets instead of real stopwatch measurements on the gemba.
Takt Time and Cycle Time
Takt time is the pace at which products must leave the line to match customer demand exactly. It is calculated as available working time per shift divided by customer demand per shift.
Cycle time is the actual time an operator or machine takes to complete an operation on one unit.
Cycle time at the bottlenecks is synchronized with takt time. If the cycle is longer than takt, the plant misses shipment dates. If it is much shorter, overproduction starts and the warehouse fills up with semi-finished goods.
Confusing the two and tuning lines for maximum machine output regardless of the real shipment pace.
Line Balancing and the Yamazumi Chart
Evening out the workload across consecutive workstations so that queues do not build up in front of some machines while others stand idle.
Teams build a Yamazumi bar chart showing, for each station, value-adding time, supporting work and waste against the takt line. Operations are then redistributed between stations until every operator is loaded evenly at 90–95% of takt.
Speeding up a machine that is already the fastest instead of moving operations off the overloaded station.
One-Piece Flow
A way of organizing production in which parts move from one operation to the next one at a time, or in minimal batches, without building up stock between operations.
Areas are rebuilt from linear departments into compact U-shaped cells. As soon as a machine finishes a part, the operator passes it to the next station. The time a product spends in the shop drops from days to tens of minutes, and defects are caught immediately.
Introducing one-piece flow while breakdowns are frequent and unpredictable or changeovers are long. The flow will keep stopping.
Theory of Constraints (TOC)
Eliyahu Goldratt’s approach: the output of the whole system is set by a single constraint, the bottleneck. Improvements outside the bottleneck do not increase output.
Five focusing steps: identify the constraint, decide how to exploit it, subordinate everything else to it, elevate the constraint and go back to step one. Material release is synchronized with the pace of the bottleneck using the drum-buffer-rope method.
Pushing for 100% utilization of every machine. In make-to-order production this floods the shop with work-in-process, lead times stretch, and output does not grow.
Operational Excellence
A state in which a company consistently keeps its promises to customers on quality, delivery and cost, and improvement is continuous and does not depend on individual people. It combines Lean, Six Sigma, quality management and people development.
It is assessed by a set of key metrics (quality, on-time delivery, productivity, safety) and by the maturity of the management system: whether there are standards, regular management routines, a problem-solving system and training.
Reducing Operational Excellence to a cost-cutting project. One-off savings without a management system disappear as soon as the project is closed.
Logistics and Pull
Kanban
A pull method for controlling inventory and production with signals: cards, bins or electronic tags. The upstream process produces or delivers material only when the downstream process has used it up.
For each item the container size and the number of cards are calculated from consumption and replenishment time, and storage locations and the delivery route are defined. The number of cards in the system caps work-in-process.
Introducing kanban for items with unstable one-off demand. For make-to-order parts the cards sit idle while shortages remain.
Pull System
A principle in which each downstream process takes parts from the upstream one only when and in the quantity needed for the current work.
An upstream machine may not make a part until a signal arrives from the next station: a kanban card, an empty slot or an electronic trigger.
Sticking to push logic, where every shop fulfils its own plan in tonnes or square metres and fills the aisles between shops with semi-finished goods nobody needs.
Heijunka — Production Leveling
Levelling production volume and mix over time so that the workload of work areas and suppliers stays even. Instead of large batches of one product, a mixed sequence is produced in small batches.
Average demand is spread across days and shifts, a repeating weekly production pattern is set up and work orders are released through a leveling box. It only works together with shorter changeovers, otherwise small batches eat up capacity.
Levelling the schedule without cutting changeover time. The number of changeovers grows, equipment stands idle, and the shop goes back to large batches.
Mizusumashi — In-Plant Logistics Operator
A dedicated worker who follows a standard route and fixed schedule to supply workstations with materials, fasteners and tooling and to take away finished parts. The Japanese name means water strider.
Machine operators no longer leave their machines to fetch components. The mizusumashi delivers materials in small batches on kanban signals straight to the work area, within the operator’s reach.
Turning the mizusumashi into an ordinary porter with no schedule or route who runs whenever a supervisor shouts for a pallet.
Parts Supermarket and Fixed-Location Storage
A buffer area between operations with strict maximum and minimum stock levels, organized like a grocery store: the customer takes what it needs and the supplier refills the empty slot.
Teams install gravity-flow racks, colour-code stock levels (green is normal, yellow means reorder, red means critical shortage) and follow the FIFO principle.
Setting up huge buffer stores with no capacity limit. The supermarket turns into a graveyard of frozen metal or glass.
FIFO — First In, First Out
A material-flow principle in which the part or blank that arrives at an area first is the first to move on to further processing.
Teams design flow-through inclined roller racks or lanes: parts are loaded from one side and taken only from the opposite side. This keeps materials from ageing and coatings and blanks from deteriorating in storage.
Stacking products in dead-end piles. The bottom layers sit for months, gather dust and lose their appearance.
Built-in Quality
Jidoka — Autonomation
The principle of built-in quality: the machine or the operator stops the process at the first abnormality so that defects do not move further down the flow. The problem is solved immediately, while the cause is still visible.
Machines are fitted with sensors and limiters that stop the cycle when something goes wrong, and operators get both the right and the duty to stop the line. Every stop is recorded and analysed down to the root cause.
Granting the right to stop the line but punishing people for downtime. Operators stop pulling the cord, and defects again pass to the next process and to the customer.
Andon
A visual and audible signal system for problems at the workstation: a stack light, a display board, a button or a pull cord. The signal calls the supervisor or support team immediately, not at the end of the shift.
Each signal type (no material, breakdown, defect) gets an owner and a target response time, and the signals are logged and analysed by frequency and duration. Andon connects jidoka with real help for the operator.
Installing lights without a response procedure. The signal is on, nobody comes, and within a month everyone ignores the andon.
Poka-yoke — Error Proofing
A simple device or design feature that prevents a mistake or detects it immediately. Quality is ensured by the design itself, not by a person’s attention.
Examples: a go/no-go gauge at the operation, asymmetric fixtures that cannot be installed the wrong way, a part-presence sensor, a fastener counter. Where to install error proofing is decided from the statistics of recurring defects.
Fighting recurring defects by adding more quality inspectors. Inspection finds a defect after it has been made, while poka-yoke prevents it from being made.
The Three No’s of Quality
The basic rule of a built-in quality culture:
- Do not accept defects from the previous process.
- Do not make defects at your own workstation.
- Do not pass defects on to the next process.
Every operator is given the right and the duty to stop the operation and send a part back if the previous station passed it on with a deviation. This way defects cannot stay hidden.
Demanding that workers hit the plan at any cost, which forces them to turn a blind eye to defective parts and pass them down the line.
5 Whys — Root Cause Analysis
A method for finding the root cause of a failure: the question “Why did this happen?” is asked at least five times in a row, moving from the visible symptom down to the systemic flaw in the process.
After a breakdown or defect, the supervisor gathers a working group at the machine and unwinds the chain of facts: the machine stopped → a fuse blew → the pump was overloaded → the filter was clogged → there was no filter-cleaning procedure. The countermeasure is a filter-cleaning standard, not just a new fuse.
Stopping at the first or second level (“the operator pressed the wrong button”) and punishing the person instead of changing the tooling, sensors or procedure.
Ishikawa Diagram (Fishbone)
A problem-analysis tool that sorts the possible causes of a defect into basic categories: man, machine, material, method, measurement and environment (the 5M+E model).
When a complex defect keeps recurring, such as bubbles in laminated glass or deviations in weld geometry, a working group fills in the branches of the diagram in a brainstorming session and then tests each hypothesis with measurements.
Filling in the diagram from guesswork, without real process measurements or batch parameters.
PDCA Cycle (Deming Cycle)
The basic algorithm of continuous improvement:
- Plan: identify the problem, collect data, find the root cause and plan the solution.
- Do: implement the countermeasure on a pilot sample or a limited area.
- Check: measure the result and compare it with the target.
- Act: if the target is met, standardize and roll out; if not, go back to the analysis.
Every kaizen project or countermeasure on the problem-solving board is run strictly through the PDCA stages, with a closing date for each stage.
Jumping from Plan straight to Act (“we came up with it, let’s roll it out plant-wide”) and skipping Check. Ineffective ideas get replicated and deliver no financial result.
A3 Report — Problem Solving on One Sheet
A Toyota method for solving a complex production problem and agreeing on management decisions that fits on a single A3 sheet.
The sheet is divided into sections: problem background, current state in figures, root-cause analysis (5 Whys, Ishikawa), target state, action plan, confirmed effect and updated standard. A manager can approve the project in five minutes because the whole logic is on one sheet.
Writing 40-page reports and memos that nobody reads instead of a concise visual summary of the facts.
Kamishibai — Layered Process Audit
A system of quick visual standard audits using two-coloured cards (red on one side, green on the other) on a dedicated board on the shop floor.
A supervisor or shop manager pulls a random card with a short check from its pocket, for example “check the cutter tightening torque” or “check the 6S zone markings”. If the standard is met, the card is turned to green; if not, it is turned to red and a corrective action is recorded right away.
Doing the checks as a formality and turning cards to green without going to the machine.
People and Standards
Kaizen
Continuous improvement in small steps driven by the employees themselves. Small changes are made every day instead of one big project every few years.
It runs on a suggestion system with fast implementation, short kaizen sessions on the shop floor and problem solving through the PDCA cycle: problem, cause, countermeasure, check of the result. Speed matters: a supervisor’s suggestion should be reviewed within days, not months.
Collecting suggestions without implementing them, or paying bonuses for the number of ideas. People soon stop suggesting when they see no result, and a bonus per idea produces a stream of formal, empty suggestions.
Kaizen Blitz (Kaizen Event)
A 3–5 day hands-on workshop held by a cross-functional team right on the shop floor and focused on one specific problem, such as cutting changeover time on a cutting line or reorganizing a kitting area.
Participants are freed from their regular duties. Day 1 is time studies and an audit, day 2 is finding waste and ideas, days 3–4 are moving equipment, marking floors and building carts, and day 5 is launching the new process, calculating the economic effect and fixing the standard.
Running a kaizen blitz as a classroom training with no physical changes on the shop floor and no authority to move machines and racks.
Gemba
The place where value is created: the shop floor, the work area, the line. The gemba principle means decisions are made by observing the process first-hand, not from reports.
Managers regularly walk the floor along a set route (gemba walk), look at the flow, inventory, standards and performance boards and ask operators questions. A production audit also starts at the gemba, comparing what is seen with the accounting data.
Turning the walk into an inspection that looks for someone to blame. Problems then get hidden whenever a manager appears, and the gemba stops providing information.
Gemba Walk
A regular walk through the shop floor by senior executives along a set route to observe the flow, support people and find systemic problems, not to inspect and reprimand.
Every day the manager goes to the gemba, looks at the performance boards (safety, quality, delivery, cost), asks operators open questions (“What difficulties did you face today?”, “What standard are you missing?”), checks that countermeasures work and removes cross-functional barriers.
Turning the walk into a punitive raid by the CEO. After that, supervisors and operators start hiding problems and keeping quiet about defects.
5S and 6S — Workplace Organization
A five-step workplace organization system: sort, set in order, shine, standardize and sustain. Safety is often added as a sixth step, and the system is then called 6S.
Everything unnecessary is removed from the area, each tool, fixture and stock item gets its own marked and labelled place, and a cleaning standard with a regular checklist audit is introduced. Floor marking and storage zones link 5S to in-plant logistics.
Treating 5S as a one-off big clean-up before a management visit. Without a standard and audits the area returns to its old state within a few weeks.
Standardized Work
The current best way to perform an operation, written down: the sequence of steps, takt and cycle time, and standard work-in-process. The standard is the basis for training and the starting point for improvement.
The operation is timed at the workstation, value-adding work is separated from waiting and unnecessary motion, and a standardized work sheet is drawn up and posted at the machine. New employees are trained with the sheet, and the supervisor checks that it is followed.
Writing the standard in the office without the operators. Such a document does not match the real work, nobody follows it, and deviations become invisible.
SOP — Standard Operating Procedure
A documented and tested sequence of steps for a process operation that is the best known at the moment, with times, safety points and quality criteria.
It serves as the reference for training newcomers and assessing skills. The supervisor compares the operator’s work with the SOP: if the worker deviates from it, they are retrained, and if they have found a faster and more reliable way, the SOP itself is updated, which is kaizen in action.
Having process engineers write SOPs in an office without setters and operators. Workers will put such a dead standard in a drawer on day one.
OPL — One Point Lesson
A visual instruction of exactly one page on a single operation, safety rule or typical mistake, with 80% of the sheet taken up by photos of the right way and the wrong way.
An OPL is written right after any incident or kaizen improvement. The supervisor gathers the shift for three minutes and shows the sheet, the operators sign it, and the sheet is posted on the machine guard.
Replacing a visual OPL with a multi-page text instruction in small print that nobody on the shop floor reads.
TWI — Training Within Industry
An on-the-job instruction method that teaches newcomers complex manual and machine operations without defects and 2–3 times faster than usual.
The instructor trains a worker in four steps:
- Prepare the learner.
- Demonstrate the operation, explaining the main steps, key points and why they matter.
- Trial performance: the learner repeats the operation and says each action out loud.
- Follow-up: consolidation and regular support from the supervisor.
Teaching by the “stand next to me and watch, you’ll do it in a month” method. It breeds hidden mistakes and high turnover during probation.
Skill Matrix
A visual chart in the work area showing each employee’s current skill level for every operation and type of equipment.
Proficiency is usually split into four levels: 1 knows the theory, 2 works under supervision, 3 works independently without defects, 4 can train others. The matrix lets the supervisor cover absences immediately and plan training.
Keeping the matrix as an HR formality without linking grades and hourly pay to mastering new machines.
Hoshin Kanri — Policy Deployment
A method for cascading a company’s strategic goals through every management level down to specific projects and work-area metrics. Each level agrees its goals with the level above through discussion instead of receiving them as an order.
Annual goals are put into an X-matrix: strategy, annual objectives, priority projects, metrics and owners. Progress is reviewed monthly, which links kaizen on the shop floor to the owner’s goals.
Handing down goals without discussion or resources. Area managers sign the plan but do not believe in it, and it stays on paper.
Hoshin Kanri X-Matrix
A tool for deploying strategy on a single sheet. It links 3–5 year goals, annual priorities, key projects and measurable indicators to the senior managers responsible for them.
It helps align sales, production, purchasing and HR. Every shop-floor project is tied directly to an owner’s strategic goal, such as higher operating profit or a shorter order cycle.
A gap between the annual strategy and shift assignments: the director thinks about margins while the shop keeps pushing tonnage into the warehouse.
Figures in the calculation examples are illustrative and only show how the formula works.
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