Chapter 23
Which of the following is required by both JIT and synchronous manufacturing systems>
some work-in-process inventory
Setup time
the time that a part spends waiting for a resource to be set up to work on this same part
Queue time
the time that a part waits for a resource while the resource is busy with something else
Wait time
the time that a part waits not for a resource but for another part so that they can be assembled together
Processing time
the time that the part is being processed
Idle time
the unused time that represents the cycle time less the sum of the setup time, processing time, queue time, and wait time
The primary way synchronous manufacturing (TOC) differs from MRP systems is that TOC can:
vary process and transfer batch sizes
What is the relationship between a process batch size and a transfer batch size?
-they can be the same size -the transfer batch size can be smaller
2 measurements must be used to measure a firm's performance
1) one from the financial point of view 2) one from the operations point of view
Goldratt's Rules of Production Scheduling
1. Do not balance capacity, balance production flow 2. The level utilization of a non-bottleneck resource is not determined by its own potential but by some other constraint in the system 3. An hour lost at a bottleneck is an hour lost for the entire system 4. An hour saved at a non-bottleneck doesn't improve the system 5. Bottlenecks govern both throughput and inventory in the system 6. Transfer Batch is not necessarily equal to the Process Batch 7. Process Batches should be variable both along their route and in time 8. Priorities can be set only by examining the system's constraints
Goldratt's Theory of Constraints (TOC)
1. Identify the system contraints. (No improvemet is possible unless the constraint or weakest link is found.)
Which of the following best describes synchronous manufacturing as it relates to firm goals?
The entire production process working in harmony to achieve profit goals.
The goal of any firm:
The goal of a firm is to make money
When nonbottleneck resources are scheduled with larger batch sizes, what happens?
They risk becoming bottlenecks
When manufacturing is truly synchronized, its emphasis what?
Total system performance
What nonbottleneck operation X feeds bottleneck operation Y (X-->Y), what happens?
Work in process builds up between X and Y
What terms are used to compute dollar days?
a measurement of the value of inventory and the time it stays within an area. Multiply the total value of inventory by the number of days inventory spends within a department.
Synchronous manufacturing
a production process working in harmony to achieve the goals of the firm
An MRP system uses ______ scheduling derived from the master production schedule; whereas, synchronous manufacturing uses a ______ scheduling system focused on critical resources.
backward; forward
A _____ is any resource whose capacity is less than the demand placed upon it.
bottleneck
The bottleneck in the process is often considered a system control point. This control point is also called the ______?
drum
A process has three machines A, B, and C. A feeds B and B feeds C. (A-->B-->C) B is the bottleneck. An improvement initiative improves C and save three hours per week. What happens to the output of the process?
it stays the same
Accounting systems can compel operations managers and supervisors to focus on ______ systems rather than the firm's ultimate _______.
measurement, goals
A production quantity large enough or small enough to be processes in a particular length of time is called?
process batch
Any resource whose utilization is close to capacity and could become a bottleneck if not scheduled carefully is called what type of resource?
(CCR) capacity-constrained resource
To test whether productivity has increased, we should ask which of these questions?
-Has the action taken increased throughput? -Has it decreased inventory? -Has it decreased operational expense
Which of the following is/are key differences between JIT systems and synchronous manufacturing?
-JIT is most often used in repetitive manufacturing environments -JIT requires a stable production level -JIT does not allow very much flexibility in the products produced -HIT still requires work-in-process when used with kanbans -Vendors need to be located nearby
Which of the following is a key financial measurement?
-Net profit -Cash flow -ROI (return on investment)
Which of the following is/are ways to save time in a process as it pertains to the bottleneck operation?
-better tooling -higher-quality labor -larger batch sizes -reduction in setup times
Identify the negative impact of inventory on a firm's performance as well as the factors that contribute to this.
-carrying cost -lengthening lead times -creating problems with engineering changes
If the drum is not a bottleneck but a CCR, we might want to create two buffer inventories. Where?
-in front of the CCR -at the end
What happens when schedulers try to reduce setup time by running larger batches?
-investment in inventory increases -work in process increases
Cost accounting is used for what?
-performance measurement -cost determinations -investment justification -inventory valuation
Which of the following is/are viable ways to identify the bottleneck in a process?
-run a capacity resource profile -use knowledge of the particular plant, look at the system in operation, and talk with supervisors and workers.
In synchronous manufacturing thinking, however, making all capacities the same is viewed how?
A bad decision
Where is synchronous manufacturing most vulnerable to defects
At the bottleneck
If a bottleneck does not require setup time to change products, how should one schedule the sequence of products?
In the order of required customer deliveries
According to Goldratt, a key operational measure is which of the following?
Inventory
In which type of production system is quality more critical for continuous product flow?
JIT
According to Goldratt, what is the only thing that can guarantee long-term survival of the firm?
Making money
If a process flows from A to B to C, and each process must be completed before passing to the next step, then B and C are _______ events?
dependent
Which of the following is not typically a difference between marketing and production organizations?
desire to exceed customer expectations