Quality

What is quality management?

Coordinated activities used to direct and control an organization with respect to quality.

What is quality planning?

Determining quality objectives and the processes and resources needed to achieve them.

What is quality assurance?

Planned activities that provide confidence that quality requirements will be met.

What is quality control?

Techniques used to monitor processes and verify that quality requirements are being met.

What is the main focus of quality assurance?

Preventing quality problems by ensuring proper processes and systems are in place.

What is the main focus of quality control?

Monitoring process or product performance and identifying quality problems.

What does TQM stand for?

Total Quality Management.

What is Total Quality Management?

An organization-wide approach emphasizing customer satisfaction and continuous improvement.

What is the primary goal of TQM?

Long-term customer satisfaction through continuous improvement.

Who participates in TQM?

Employees throughout the entire organization.

What role does the customer have in TQM?

Customer needs and satisfaction are central to defining quality.

What does continuous improvement mean in TQM?

Processes and products are continually evaluated and improved.

What type of decision making is emphasized by TQM?

Fact-based decision making using data and performance information.

What did Deming emphasize about quality?

Quality should be built into processes rather than achieved through final inspection.

What does Six Sigma primarily seek to improve?

Process quality by reducing defects and variation.

Is a higher or lower sigma quality level better?

Higher; it represents fewer defects and better process performance.

What does DMAIC stand for?

Define, Measure, Analyze, Improve, and Control.

What is the Define stage of DMAIC?

Identify the problem, customer requirements, and improvement goals.

What is the Measure stage of DMAIC?

Determine current process performance using data.

What is the Analyze stage of DMAIC?

Identify the root causes of defects or poor performance.

What is the Improve stage of DMAIC?

Develop and implement solutions to address root causes.

What is the Control stage of DMAIC?

Maintain improvements and prevent the process from returning to previous performance.

What does QFD stand for?

Quality Function Deployment.

What is the primary purpose of QFD?

Translate customer needs into technical or engineering requirements.

What is the starting point of QFD?

The voice of the customer.

What is the voice of the customer?

The needs, wants, expectations, and requirements of customers.

What is the House of Quality?

A relationship matrix connecting customer requirements to product or engineering characteristics.

What quality method uses the House of Quality?

Quality Function Deployment (QFD).

What are the WHATs in the House of Quality?

The customer's needs and requirements.

What are the HOWs in the House of Quality?

The technical or engineering characteristics used to satisfy customer needs.

What does the roof of the House of Quality evaluate?

Relationships and correlations among technical requirements.

What can the House of Quality reveal about technical requirements?

Whether requirements support or conflict with one another.

What is the purpose of a competitive assessment in the House of Quality?

Compare the product or service with competitors from a customer perspective.

What is an Ishikawa diagram?

Another name for a fishbone or cause-and-effect diagram.

What is the primary purpose of a fishbone diagram?

Identify and organize possible causes of a problem.

Where is the problem or effect placed on a fishbone diagram?

At the head of the fish.

What are the traditional 4 Ms of a manufacturing fishbone diagram?

Manpower, Machines, Methods, and Materials.

What two categories may be added to create the 6 Ms?

Measurement and Environment.

What quality tool is used to brainstorm possible causes of a defect?

Fishbone or cause-and-effect diagram.

What is the Taguchi view of quality?

Any deviation from the target creates quality loss.

Does Taguchi consider a product within specifications to have zero quality loss?

No. Deviation from the target still creates loss.

What happens to Taguchi quality loss as performance moves farther from the target?

Quality loss increases.

What is the central idea behind the Taguchi loss function?

Quality should focus on closeness to the target rather than merely meeting specification limits.

What does robust quality mean in Taguchi's philosophy?

Performance remains consistent despite sources of variation or noise.

What is statistical process control (SPC)?

The use of statistical methods to monitor and control process performance.

What is the primary purpose of a control chart?

Determine whether a process is stable and under statistical control.

What are control charts designed to distinguish?

Common-cause variation from special-cause variation.

What is common-cause variation?

Natural random variation inherent in a process.

What is special-cause variation?

Variation caused by a specific identifiable source or event.

What should be done when special-cause variation is detected?

Investigate and eliminate or control the identifiable cause.

What do control limits represent?

The expected range of variation based on actual process behavior.

What do specification limits represent?

Acceptable product requirements established by customers or design.

What is the difference between control limits and specification limits?

Control limits come from process behavior; specification limits come from requirements.

Can a process be in statistical control but still fail specifications?

Yes. Stability does not necessarily mean the process is capable.

What does an X-bar control chart monitor?

The process average or mean.

What does an R chart monitor?

Process variability using subgroup ranges.

What type of data are X-bar and R charts used for?

Measured or variable data.

What does a p chart monitor?

The proportion or fraction of units that are defective.

What does an np chart monitor?

The number of defective units.

What does a c chart monitor?

The number of defects or nonconformities.

What does a u chart monitor?

The number of defects per unit.

What is the difference between a defective unit and a defect?

A defective unit is unacceptable; one unit can contain multiple defects.

What is stratification on a control chart?

A pattern in which observations cluster unusually close to the centerline.

What control-chart pattern is the opposite of stratification?

A mixture pattern.

What is a mixture pattern on a control chart?

Points occur away from the centerline with relatively few points near the center.

What does process capability evaluate?

Whether a stable process can consistently meet specification requirements.

What does Cp measure?

Potential process capability based on process spread; it does not consider centering.

What does Cp > 1 mean?

The process spread fits within the specification limits; the process is potentially capable.

What does Cp = 1 mean?

The process spread exactly matches the specification width; it just fits.

What does Cp < 1 mean?

The process spread is wider than the specification limits; the process is not capable.

Is a larger or smaller Cp better?

Larger; process variation is smaller relative to the allowable specification range.

What important factor does Cp not account for?

Whether the process is centered within the specification limits.

What does Cpk measure?

Actual process capability considering both process spread and process centering.

What does Cpk > 1 mean?

The process is capable while accounting for its actual centering.

What does Cpk = 1 mean?

The process just meets the capability threshold at its nearest specification limit.

What does Cpk < 1 mean?

The process is not adequately capable on at least one side of the specifications.

What does Cp = Cpk mean?

The process is centered between the upper and lower specification limits.

What does Cp > Cpk mean?

The process is off-center; its mean is shifted toward one specification limit.

Can Cpk normally be greater than Cp?

No. Cpk is less than or equal to Cp.

What does a high Cp but much lower Cpk indicate?

The process has potentially acceptable variation but is poorly centered.

If Cp is high but Cpk is low, what needs improvement?

Process centering; the process mean should be moved closer to the target.

What is an easy way to remember Cp versus Cpk?

Cp = Potential capability; Cpk = capability that Keeps track of centering.

What is acceptance sampling?

Using a sample from a lot to decide whether to accept or reject the entire lot.

What is a single sampling plan?

One sample is inspected and used to make an accept-or-reject decision.

What is a double sampling plan?

A second sample may be taken when the first sample does not provide a clear decision.

What is a multiple sampling plan?

Successive samples are inspected until an accept-or-reject decision can be made.

What is producer's risk?

The risk of rejecting a lot that is actually of acceptable quality.

What type of error is producer's risk?

Type I error.

What is consumer's risk?

The risk of accepting a lot that is actually of unacceptable quality.

What type of error is consumer's risk?

Type II error.

What does an operating characteristic (OC) curve show?

The probability of accepting a lot at different levels of lot quality.

As the defective rate increases, what happens on an OC curve?

The probability of accepting the lot decreases.

What does DOE stand for?

Design of Experiments.

What is the purpose of DOE?

Systematically determine how input factors affect an output or response.

What is a factor in DOE?

An input variable that is intentionally investigated.

What is a level in DOE?

A particular setting or value of a factor.

What is a response in DOE?

The output or performance measure observed during the experiment.

What is a main effect in DOE?

The effect that one factor has on the response.

What is an interaction effect in DOE?

The effect of one factor depends on the level of another factor.

What is the purpose of screening in DOE?

Identify which factors have important effects on the response.