11. Lean, Just-in-Time and Theory of Constraints

Introduction: From Efficient Operations to Flow

Production Planning and Control is concerned not only with deciding what should be produced, but also with ensuring that materials, information, labour, equipment and time are coordinated so that customer requirements are met with minimum delay and waste. Traditional production systems often seek efficiency by maximizing machine utilization, producing in large batches and maintaining inventories as protection against uncertainty. Although such practices may improve local efficiency, they can also create long lead times, hidden defects, excessive work-in-process and weak responsiveness.

Lean production, Just-in-Time (JIT) and the Theory of Constraints (TOC) offer complementary approaches to this problem. Lean focuses on the systematic elimination of activities that do not create customer value. JIT emphasizes producing and replenishing only what is needed, when it is needed, and in the required quantity. TOC concentrates on identifying and managing the constraint that limits the throughput of the entire system. Together, these approaches shift attention from isolated departmental performance to the flow of value through the complete production system.

Their importance in production planning is practical as well as theoretical. A planner must determine the rhythm of production, establish replenishment signals, sequence jobs, reduce setup time, balance workloads and protect the system from disruption. These decisions require an understanding of takt time, pull systems, Kanban, production leveling, small-lot production, SMED, standardized work and drum-buffer-rope scheduling. The effectiveness of these methods depends on disciplined implementation rather than on the use of isolated tools.

Learning Objectives

After studying this chapter, the student should be able to:

1. Explain the principles and relationships among Lean, JIT and TOC.

2. Distinguish value-adding, necessary but non-value-adding, and pure waste activities.

3. Calculate and interpret takt time, cycle time, throughput and basic capacity measures.

4. Design a simple pull system using Kanban signals.

5. Explain the role of production leveling, small lots, SMED and standardized work in improving flow.

6. Apply the five focusing steps and drum-buffer-rope logic to a constrained production system.

7. Evaluate the managerial, technological and organizational requirements for implementation.

8. Diagnose common failure modes and recommend appropriate improvement actions.

The Logic of Lean Production

Lean is a management philosophy and operating system for creating customer value with fewer resources and less delay. It is not simply a cost-reduction programme. Cost reductions achieved by reducing inspection, maintenance or training may damage quality and reliability. Lean instead seeks to remove the causes of unnecessary consumption while strengthening the capability of the process.

Customer value is determined by the characteristics for which the customer is willing to pay, including function, quality, delivery reliability and sometimes customization. An activity is value-adding when it transforms the product or service in a way that the customer requires and when it is performed correctly the first time. Inspection, movement, waiting, storage and rework generally do not add value. Some activities, such as regulatory inspection or a temporary safety control, may be necessary even though the customer does not directly value them. These should be reduced or redesigned, but they cannot be eliminated without considering risk and compliance.

Lean analysis commonly identifies seven forms of operational waste: overproduction, waiting, transportation, over-processing, inventory, motion, and defects. Many organizations also identify underutilization of human capability as an additional form of waste. Overproduction is particularly damaging because it creates or conceals other wastes. Producing earlier or in greater quantity than required leads to inventory, handling, storage, obsolescence and delayed detection of quality problems.

The five widely used Lean principles are:

• Specify value from the customer’s perspective.
• Identify the value stream and expose waste.
• Make value flow continuously wherever possible.
• Establish pull according to actual downstream demand.
• Pursue perfection through continuous improvement.

These principles should not be interpreted as a sequence that ends after one cycle. Improvements in flow reveal new problems, and the system must repeatedly examine causes, test countermeasures and stabilize the improved process.

Just-in-Time and the Economics of Flow

JIT is the coordinated production and delivery of the right item, in the right quantity, at the right time. It seeks to reduce inventories and lead times while making problems visible. Inventory is not automatically waste in every situation; it may protect against demand variation, supplier unreliability, long setup times or process instability. However, excessive inventory can hide these problems. JIT therefore treats inventory reduction as a method for exposing and solving underlying causes, not as an objective pursued without safeguards.

A JIT system requires several conditions: reliable processes, short and repeatable setup times, capable suppliers, preventive maintenance, accurate information, disciplined scheduling and employee involvement. Reducing inventory before achieving these conditions may produce stockouts and production interruptions rather than improvement. JIT is consequently better understood as a system of interdependent practices than as a policy of maintaining zero inventory.

A central planning concept is takt time:

Takt time = Available production time during the period / Customer demand during the period

If a plant has 420 net available minutes per shift and customer demand is 140 units, takt time is 3 minutes per unit. Takt time represents the pace required to satisfy demand; it is not the same as the actual cycle time of a machine. For stable flow, the effective cycle time at each required work position should normally be no greater than takt time. If cycle time is much lower, the resource may have excess capacity or may be producing ahead of demand. If it is higher, the process cannot meet demand without additional capacity, overtime, inventory or a change in the process.

Takt time must be recalculated when demand, available time, product mix, breaks, planned maintenance or staffing patterns change. It also should be used with caution in highly variable job shops, where a single takt may not represent the economic or technical characteristics of every order.

Pull Systems, Kanban and Production Leveling

A push system releases work according to a central schedule, often without regard to the immediate capacity or inventory condition of the next operation. A pull system authorizes production or movement only when a downstream process consumes material or signals a requirement. Pull reduces uncontrolled accumulation and links production more closely to actual demand.

Kanban is a signalling method used to control pull. A Kanban may be a card, container, electronic message, barcode event or other authorization. In a two-card system, a withdrawal Kanban authorizes movement of material and a production Kanban authorizes replenishment. When a downstream process consumes a standard container, the empty container or its electronic equivalent signals the upstream process to produce the defined quantity.

A simplified estimate of the number of Kanban containers is:

N = D × L × (1 + S) / C

where N is the required number of containers, D is demand per time period, L is replenishment lead time, S is a safety factor, and C is the quantity per container. The result is normally rounded upward. The safety factor should reflect process and supply uncertainty rather than serve as a substitute for improvement. As reliability improves and lead time decreases, the number of containers can be reduced.

Kanban is appropriate when demand is reasonably repetitive, containers have standard quantities, processes are stable and replenishment routes are defined. It is less suitable for unique engineering orders, highly erratic demand or processes whose output cannot be replenished within an acceptable period. In those settings, a hybrid planning method may combine material requirements planning for long-term coordination with pull signals for repetitive subassemblies.

Pull cannot function effectively if upstream processes produce defective parts, changeover times are excessive or replenishment quantities are too large. Kanban therefore depends on quality at the source, visible standards, quick response to abnormalities and disciplined adherence to the signal.

Production leveling, or heijunka, smooths the volume and mix of production over a planning horizon. If a customer requires 100 units on Friday and the plant produces all 100 on Friday, the system experiences peaks in labour, materials and capacity. A level schedule may distribute production across the week. Mix leveling goes further by sequencing different models in a repetitive pattern rather than producing one model in a large batch followed by another. Leveling reduces demand amplification and makes resource requirements more predictable, but it requires small lots, rapid changeovers and reliable supply.

Small Lots, SMED and the Reduction of Lead Time

Large batches are often justified by the belief that setup costs must be spread over many units. This may be economically rational when setups are genuinely long and infrequent. However, large batches also increase inventory, extend response time, delay defect detection and make production less flexible. The strategic answer is not merely to tolerate costly setups; it is to reduce setup time and make smaller lots feasible.

Single-Minute Exchange of Die (SMED) is a structured approach to reducing changeover time. Its basic logic is to distinguish between:

• Internal activities, which can be performed only while the machine is stopped.
• External activities, which can be performed while the machine is operating.

Improvement begins by observing and documenting the complete changeover. External activities are moved outside the shutdown period. Internal activities are simplified through locating pins, quick clamps, standardized settings, preset tools and parallel work. Finally, the method is refined through elimination of adjustment, visual guidance and error-proofing. The term “single-minute” expresses the ambition of reducing setup duration to a single-digit number of minutes; it is not a requirement that every setup literally take less than ten minutes.

Reduced setup time changes the planning problem. More frequent changeovers can support mixed-model production, lower finished-goods inventory and improve response to demand. Nevertheless, setup reduction should not be pursued without considering tool life, quality validation, safety and the total cost of the changeover. A fast but uncontrolled setup may increase defects or create unsafe conditions.

Standardized Work and Stability

Standardized work defines the current best known method for performing a task safely, with the required quality, within the required time. It normally specifies takt time, work sequence and standard in-process stock. Standardization provides a baseline for training, auditing and improvement. Without a stable method, it is difficult to determine whether performance changes result from a genuine improvement or from uncontrolled variation.

Standardized work is not intended to prevent employee judgment or continuous improvement. Workers should be involved in developing and revising standards because they possess practical knowledge of abnormal conditions and task difficulty. Once a better method is validated, the standard must be updated and communicated. A standard that exists only in a manual but is not visible, understood and followed has little operational value.

Stability also depends on the familiar Lean foundations of reliable equipment, capable processes, appropriate materials and trained people. Total productive maintenance, preventive maintenance, quality-at-source practices, 5S and visual management support these foundations. The purpose of 5S is not cosmetic tidiness; it is to make abnormalities, missing items, unsafe conditions and unnecessary movement immediately visible.

Theory of Constraints: Managing the System’s Limitation

The Theory of Constraints views every system as having at least one constraint that limits its ability to achieve its goal. In a production system, the constraint may be a machine, labour skill, policy, market condition, supplier, information rule or physical capacity. Improving a non-constraint may produce local gains without increasing total throughput. For this reason, TOC emphasizes system-level performance rather than isolated utilization.

TOC commonly evaluates three operational measures:

• Throughput: the rate at which the system generates money through sales, not merely the rate at which it produces inventory.
• Inventory or investment: money tied up in items intended for sale, transformation or support.
• Operating expense: money spent to convert inventory into throughput.

The five focusing steps are:

1. Identify the constraint. Determine what currently limits the system’s throughput.

2. Exploit the constraint. Obtain the maximum effective output from the constraint using existing resources—for example, reduce idle time, prioritize profitable work and avoid processing defective material.

3. Subordinate everything else. Align non-constraints with the needs of the constraint, even if this means accepting lower local utilization.

4. Elevate the constraint. Add capacity through overtime, alternative equipment, subcontracting, process redesign or investment.

5. Repeat the process. Once the constraint moves, prevent organizational inertia from making the previous constraint the permanent focus.

The phrase “subordinate everything else” is often difficult for managers because it challenges the belief that every department should maximize utilization. If a bottleneck can process only 80 units per day, producing 100 units at an upstream operation creates inventory rather than throughput. The non-bottleneck should therefore work to the rate required by the constrained flow, unless there is a clearly justified reason to build a controlled buffer.

Drum-Buffer-Rope Scheduling

Drum-buffer-rope (DBR) is a TOC scheduling method. The drum is the pace set by the constraint. The buffer is time or material protection placed before the constraint or customer shipment so that minor disturbances do not stop the flow. The rope is the communication mechanism that releases work into the system at a rate synchronized with the drum and buffer condition.

Suppose a fabrication line contains three operations and the second operation can process only 50 units per shift, while the other operations can process 70 units. The second operation is the drum. A controlled buffer of work is maintained before it, and material release is tied to the expected consumption of the drum rather than to the 70-unit capacity of the first operation. If the buffer becomes too small, management investigates the cause; if it becomes excessive, release is slowed or the process is corrected.

DBR does not mean that every resource remains idle whenever the constraint is busy. Non-constraints may perform useful work, maintenance, training or carefully authorized replenishment. The principle is that work should not be released merely to keep every resource busy. DBR is especially useful where variability is high and a single resource clearly governs throughput. It can be integrated with Lean methods: Lean reduces waste and variation, while TOC ensures that improvement effort is directed toward the current limiting factor.

Integrating Lean, JIT and TOC

Lean and TOC are sometimes presented as competing philosophies, but their practical emphasis differs more than their ultimate purpose. Lean asks where waste exists and how flow can be improved. JIT provides a demand-linked replenishment logic. TOC asks which constraint currently determines system throughput and where improvement will have the greatest effect.

An integrated approach can follow this sequence:

1. Map the value stream and quantify demand, lead times, inventory and process capability.

2. Calculate takt time and compare it with effective cycle times.

3. Identify the constraint using actual flow data rather than departmental opinion.

4. Protect and exploit the constraint through quality at the source, reliable maintenance and priority rules.

5. Use DBR or an appropriate pull signal to control release.

6. Reduce setups and stabilize work so that smaller lots and leveled production become possible.

7. Establish standardized work and visual controls.

8. Reduce buffers progressively as reliability improves.

9. Reassess the system because the constraint may have moved.

The integration must preserve distinctions. A Kanban quantity is not necessarily the same as a TOC buffer. Takt time is a demand pace, whereas the drum is the pace of the constraint. A system may have takt time of four minutes but a bottleneck cycle time of five minutes; in that case, the system requires capacity improvement, demand adjustment, overtime, outsourcing or another strategic response. Merely increasing Kanban cards will not solve the capacity gap.

An Illustrative Case: Improving Flow at Meridian Components

Background

Meridian Components, a fictional manufacturer of precision brackets, supplies three standard models to an equipment producer. The plant operates one eight-hour shift, with 420 net production minutes after breaks and planned meetings. Average daily demand is 105 units, giving a takt time of four minutes per unit. The process consists of cutting, stamping, deburring, inspection and packing.

Situation and Problem

The plant releases work in large weekly batches. Cutting and stamping are frequently busy, but finished goods inventory is high and customer lead time is nine working days. The stamping press requires 90 minutes to change from one model to another. Defects are often discovered at final inspection, and operators report that priorities change several times during a shift.

An initial value-stream review finds that stamping has an effective cycle time of 4.8 minutes per unit, above the four-minute takt time. It is therefore the principal constraint. The plant’s weekly schedule also creates uneven model demand: one model is produced for two days, followed by another model. Upstream cutting continues to run when stamping is not ready, creating queues.

Analysis

The management team first distinguishes local efficiency from system throughput. Cutting has spare capacity, but its additional output cannot be sold until it passes through stamping. The team therefore stops measuring cutting success primarily by utilization and begins tracking stamping throughput, queue size, first-pass yield and schedule adherence.

A changeover study separates internal and external work. Tools are prepared after the previous batch has finished, settings are preset, and quick clamps replace several bolted connections. The 90-minute setup is reduced to 25 minutes. Operators also create a standard sequence for setup and a checklist for first-piece approval.

The plant then introduces a leveled schedule with smaller repeated batches. A withdrawal signal from deburring authorizes movement of a standard container from stamping. A production signal authorizes stamping to replenish the container. Cutting is released according to the rope linked to stamping rather than according to its own available capacity. A small time buffer is maintained before stamping to protect it from short interruptions.

Strategy and Solution

The improvement programme uses both Lean and TOC principles. Stamping is exploited by scheduling qualified operators, eliminating avoidable waiting for tools and ensuring that material is available. Defective material is not allowed to consume bottleneck time. Cutting and deburring are subordinated to the stamping schedule. The setup reduction supports mixed-model production and lower container quantities. Standardized work is posted at each operation, and abnormalities are recorded at the point of occurrence.

After the process is stabilized, the team investigates why stamping remains above takt. A die modification reduces handling and lowers the effective cycle time to 4.1 minutes. A limited amount of overtime is used while a second tool is evaluated. The team does not add Kanban containers simply to conceal the capacity gap.

Outcome

In this illustrative case, the plant’s lead time falls because uncontrolled queues are reduced, although the precise result depends on demand and process conditions. More importantly, management gains a clear control logic: stamping determines the production rhythm, buffers are visible, and release is linked to actual consumption. The plant also becomes capable of changing models more frequently without relying on large finished-goods inventories.

Learning Points

The case demonstrates five lessons. First, the most heavily utilized resource is not automatically the system’s most important resource; the constraint must be linked to throughput. Second, reducing setup time is a capacity and responsiveness improvement, not merely a maintenance activity. Third, pull systems require stable quantities, quality and replenishment rules. Fourth, production leveling cannot be separated from small-lot capability. Finally, Lean and TOC are most powerful when improvement is directed toward the current system limitation.

Measurement and Managerial Control

Implementation requires measures that reflect flow rather than isolated activity. Useful indicators include lead time, throughput, on-time delivery, work-in-process, first-pass yield, setup duration, schedule adherence, buffer status and the percentage of time the constraint is available for productive work. Local utilization may still be monitored, but it should not dominate decision-making when it encourages overproduction.

A balanced review asks four questions: Is the customer receiving the required output? Is flow becoming faster and more reliable? Is quality improving at the source? Is the constraint being managed and then elevated when appropriate? Financial measures should also be considered. Reducing inventory may improve cash flow, but a stockout that stops a customer shipment may be economically damaging. Similarly, overtime at a bottleneck may be justified temporarily, but permanent overtime can indicate that capacity investment or product redesign is needed.

Digital technologies can support these practices through real-time machine data, electronic Kanban, barcode or RFID transactions, finite-capacity scheduling, statistical process control and dashboard visualization. Predictive maintenance can help protect a constraint by identifying likely equipment failure before it interrupts production. Analytics can reveal queue patterns and calculate actual cycle-time distributions. However, digital systems do not replace process discipline. Automating inaccurate data, unstable standards or poorly designed signals can make waste less visible rather than eliminate it.

Challenges, Risks and Professional Considerations

Lean and JIT programmes commonly fail when they are treated as short-term cost-cutting exercises. Reducing inventory without improving reliability transfers problems to customers and employees. Another mistake is implementing Kanban before standardizing container sizes, replenishment routes and quality requirements. Excessive Kanban quantities can recreate a push system under a different name.

Managers may also reward the wrong behaviour. If operators are evaluated only on machine utilization, they may produce ahead of demand. If purchasing is measured only on unit price, it may choose large deliveries that increase inventory and handling. Performance measures should therefore be aligned with flow, quality, responsiveness and total cost.

Employee participation is an ethical and operational requirement. Improvement should not be used to intensify work without considering ergonomics, fatigue, safety and reasonable staffing. Standardized work must include safe methods, and productivity gains should be balanced with fair treatment and capability development. Supplier requirements should also be transparent; JIT deliveries should not simply transfer inventory and uncertainty to smaller suppliers without collaboration or appropriate contractual arrangements.

Other risks include excessive dependence on a single supplier, insufficient contingency capacity, inaccurate demand forecasts, weak maintenance and failure to review the location of the constraint. A resilient system does not eliminate every buffer. It determines which buffers are necessary, makes them visible and reduces them only when the underlying risk has been addressed.

Current Developments and Best Practices

Contemporary production systems increasingly combine Lean principles with advanced planning, connected equipment and data analytics. Electronic Kanban can link consumption at the point of use with supplier or warehouse replenishment. Digital twins and discrete-event simulation can test alternative batch sizes, buffer policies and constraint scenarios before physical changes are made. Machine learning may support demand sensing and predictive maintenance, although model quality depends on accurate data and appropriate human oversight.

A mature implementation generally follows these practices:

• Begin with a clearly defined customer requirement and measurable process problem.
• Observe the actual process rather than relying solely on reports.
• Stabilize quality, maintenance, staffing and material availability before aggressive inventory reduction.
• Identify the system constraint and direct improvement resources toward it.
• Use takt time to establish demand pace, but do not confuse it with capacity.
• Reduce setup time so that small lots and mixed-model flow are economically practical.
• Make pull signals simple, visible and tied to standard quantities.
• Involve employees in designing standards and solving abnormalities.
• Use buffers deliberately and review their size as conditions change.
• Measure total system performance, not just departmental utilization.
• Reassess the constraint after every significant improvement.

Chapter Summary

Lean production seeks to create customer value by removing waste and improving the flow of work. JIT connects production and replenishment to actual demand, while Kanban provides a practical signalling mechanism for pull. Takt time expresses the pace needed to meet demand; cycle time describes the process rate and must be compared with takt when balancing work.

Production leveling smooths volume and mix, but it depends on small lots and short changeovers. SMED reduces setup time by separating internal from external activities and simplifying the remaining work. Standardized work establishes a stable, safe and repeatable method that supports both control and continuous improvement.

TOC focuses attention on the constraint that limits total throughput. Its five focusing steps—identify, exploit, subordinate, elevate and repeat—are operationalized through drum-buffer-rope scheduling. The drum sets the pace, the buffer protects flow, and the rope controls release. Lean, JIT and TOC can be integrated when managers distinguish demand pace from constraint pace, use data to identify the true limitation and pursue system-level rather than local optimization. Successful implementation requires reliable processes, employee involvement, appropriate measures, ethical working conditions and disciplined managerial follow-through.

Key Terms

Lean production: A system for creating customer value with minimal waste and improved flow.

Just-in-Time (JIT): Producing and delivering the required item, quantity and timing in response to actual need.

Value-adding activity: An activity that transforms a product or service in a way the customer requires and accepts.

Waste (muda): Resource consumption that does not create customer value.

Takt time: Available net production time divided by customer demand for the same period.

Cycle time: The elapsed time between completed units or the time required to perform a production cycle.

Pull system: A system in which downstream consumption authorizes upstream production or movement.

Kanban: A physical or electronic signal that authorizes production, withdrawal or replenishment.

Production leveling (heijunka): Smoothing production volume and product mix over time.

Small-lot production: Producing in relatively small quantities to reduce inventory and improve responsiveness.

Setup or changeover: Activities required to prepare a process to produce a different product or specification.

SMED: Single-Minute Exchange of Die, a method for reducing changeover time by separating and simplifying setup activities.

Standardized work: The documented current best method, sequence and timing for performing a task safely and consistently.

Constraint: Any factor that limits the throughput or achievement of a system’s goal.

Throughput: The rate at which a system generates money through sales or completed customer output.

Buffer: Deliberate protection in time, material or capacity against variation and disruption.

Drum-buffer-rope: A TOC scheduling method in which the constraint sets the pace, a buffer protects it and a release signal controls upstream work.

Subordination: Aligning non-constraint activities with the requirements of the system constraint.

First-pass yield: The proportion of units that meet requirements without rework or repair.

Review Questions

Short Answer Questions

1. What is the difference between takt time and cycle time?

2. Why is overproduction considered a particularly damaging form of waste?

3. What is the purpose of a Kanban signal?

4. Distinguish between internal and external setup activities in SMED.

5. What are the five focusing steps of the Theory of Constraints?

Long Answer Questions

1. Explain how Lean, JIT and pull production are related, and identify the conditions required for their successful implementation.

2. Discuss production leveling and small-lot production. How does setup-time reduction support both practices?

3. Explain standardized work and its relationship with quality, training, safety and continuous improvement.

4. Describe drum-buffer-rope scheduling and explain how it controls material release in a constrained production system.

5. Compare the Lean focus on waste elimination with the TOC focus on constraints. How can the two approaches be integrated?

Analytical / Application Questions

1. A plant has 360 net production minutes per shift and daily demand of 90 units. One operation has a cycle time of 5 minutes. Calculate takt time, assess the capacity position of the operation and recommend possible responses.

2. A factory consumes 240 components per day. Replenishment lead time is 1.5 days, the safety factor is 10 percent and each Kanban container holds 30 components. Calculate the required number of containers, rounding upward, and explain how the number might be reduced responsibly.

3. In a four-operation line, the second operation can produce 48 units per shift while the other operations can produce 70 units. Develop a drum-buffer-rope response and explain why maximizing the output of the first operation may harm system performance.

22. Multiple Choice Questions with Answers

Question 1

A plant has 420 net production minutes available per shift and demand of 140 units per shift. What is the takt time?

A. 2 minutes per unit

B. 3 minutes per unit

C. 4 minutes per unit

D. 5 minutes per unit

Correct Answer: B. 3 minutes per unit

Question 2

Which situation most clearly represents a pull system?

A. The upstream department produces to keep its machine busy.

B. Production is released according to a monthly forecast regardless of downstream inventory.

C. An upstream process replenishes a standard container after receiving a downstream consumption signal.

D. All departments produce the maximum quantity permitted by their capacity.

Correct Answer: C. An upstream process replenishes a standard container after receiving a downstream consumption signal.

Question 3

The main purpose of production leveling is to:

A. Maximize the utilization of every machine independently.

B. Smooth production volume and mix over time.

C. Increase the size of production batches.

D. Eliminate the need for customer demand information.

Correct Answer: B. Smooth production volume and mix over time.

Question 4

Which SMED action directly reduces machine downtime during changeover?

A. Performing tool preparation while the machine is stopped.

B. Moving activities that can be done externally outside the shutdown period.

C. Increasing the batch size to avoid all future changeovers.

D. Allowing operators to adjust settings without a standard method.

Correct Answer: B. Moving activities that can be done externally outside the shutdown period.

Question 5

A process has a cycle time greater than takt time. What does this generally indicate?

A. The process has more capacity than demand requires.

B. The process cannot meet the required demand pace without intervention.

C. The Kanban quantity is automatically correct.

D. Production leveling has already been achieved.

Correct Answer: B. The process cannot meet the required demand pace without intervention.

Question 6

Under the Theory of Constraints, what should management do immediately after identifying the constraint?

A. Maximize output at every non-constraint.

B. Exploit the constraint using existing resources.

C. Increase inventory throughout the entire plant.

D. Replace the constraint without examining its current utilization.

Correct Answer: B. Exploit the constraint using existing resources.

Question 7

In drum-buffer-rope scheduling, the drum represents:

A. The amount of finished-goods inventory held for emergencies.

B. The signal that authorizes unlimited upstream production.

C. The pace established by the system constraint.

D. The time required for a supplier to deliver materials.

Correct Answer: C. The pace established by the system constraint.

Question 8

Why can reducing inventory too quickly create operational problems?

A. Inventory always increases customer value.

B. Inventory reduction may expose unresolved instability in quality, supply or equipment.

C. Lower inventory automatically increases setup time.

D. Pull systems require unlimited inventory.

Correct Answer: B. Inventory reduction may expose unresolved instability in quality, supply or equipment.

Question 9

A bottleneck can process 50 units per day, while an upstream process can produce 70. Which action is most consistent with TOC?

A. Release all 70 units to maximize upstream utilization.

B. Synchronize release with the bottleneck and protect it with an appropriate buffer.

C. Stop measuring throughput and measure only upstream efficiency.

D. Increase the upstream batch size to prevent the bottleneck from becoming visible.

Correct Answer: B. Synchronize release with the bottleneck and protect it with an appropriate buffer.

Question 10

Which statement best describes standardized work?

A. A permanent rule that prevents workers from suggesting improvements.

B. The current best known safe and repeatable method for performing a task.

C. A schedule based only on forecasted demand.

D. A document used exclusively by the quality department.

Correct Answer: B. The current best known safe and repeatable method for performing a task.