Acceptance Sampling, Producer’s Risk(α), Consumer’s Risk (β) & Acceptable Quality Level (AQL)

Acceptance Sampling

Acceptance sampling is concerned with inspection and decision making regarding the entire lot/production/shipment

• A form of inspection used to accept or reject whole lot based on sample information

• Not consistent with TQM or Zero Defects philosophy

• Producer & customer agree on the number of acceptable defects

• A means of identifying not preventing poor quality

Statistical Process Control (SPC), Basic Procedure of Control Chart.

Statistical Process Control (SPC)

Statistical evaluation of the output of a process during production

- Goal is to make the process stable over time & then keep it stable unless the planned changes are made
- Statistical description of stability requires that ‘pattern of variation’ remains stable over time, not that there be no variation in the variable measured

• Process is in control has only random cause variation (inherent variability of system)

• When the normal functioning of the process is disturbed by some unpredictable events, special cause variation is added to common cause variation

Statistical Quality Control (SQC) & Process Variability

Statistical Quality Control (SQC)

A quality control system using statistical techniques to control quality by performing inspection, testing & analysis to conclude whether the product is as stated or designed quality standard

- Relying on the probability theory, evaluates batch quality & controls the quality of processes or products

- Makes the inspection more reliable & less costly

SQC is used to describe the set of statistical tools used by quality professionals

• Descriptive statistics

- Used to describe quality characteristics & relationships

• Acceptance sampling

- Used to randomly inspect a batch of products to determine acceptance or rejection of entire lot based on the results

- Does not help to identify and catch the in-process problems

• Statistical process control (SPC)

- Involves inspecting the output from a process & identifying in-process variation

- Quality characteristics are measured & charted

What is Quality Inspection? How Much to Inspect, How Often & Where to Inspect in the Process.

Inspection

An appraisal activity that compares goods or services to a standard

- Well-designed processes little inspection is necessary, inspection cannot be completely eliminated

In lean organizations, inspection is less of an issue than it is for other organizations, because have extra emphasis on quality in the design of both products/processes & workers have responsibility for quality (quality at the source).

What is Quality control? Approaches to quality assurance.

Quality control

A process that evaluates output relative to a standard & takes corrective action when output doesn’t meet standards

- The operational techniques & activities (a system for measuring & checking) used to fulfill the requirements for quality

• Incorporates a feedback mechanism system to explore the causes of poor quality or unsatisfactory performance & takes corrective actions
• Suggests when to inspect, how often to inspect, & how much to inspect.

The foundations of modern quality management: The Gurus

Walter A. Shewhart

• Pioneer of Modern Quality Control

• Founder of the control chart “father of statistical quality control.”

•  Originator of the plan-do-check-act cycle

• Perhaps the first to successfully integrate statistics, engineering, & economics

W. Edward Deming

• Theory of variance: controllable & uncontrollable variance

• PDCA cycle: Core element is ‘Management Team’

• Fourteen points for quality and productivity.

• Seven deadly sins and diseases.

• Out of Crisis (Having a satisfied customer is not enough)

- Profit in the business comes from repeat customers, customers that boast about your product & service & customers that bring friends with them

What is Brainstorming and Bench-marking?

Brainstorming

Technique for generating a free flow of ideas in a group of people

- A group of people share thoughts & ideas on problems in a relaxed atmosphere that encourages unrestrained collective thinking

- The goal is to generate a free flow of ideas on identifying problems, & finding causes, solutions, & ways to implement solutions

Bench-marking

Process of measuring performance against the best in the same or another industry

- An approach that can inject new energy into improvement efforts

- Purpose is to establish a standard against which performance is judged, & to identify a model for learning how to improve

Steps in benchmarking process

• Identify a critical process that needs improvement (order entry, distribution) 

• Identify an organization that excels in the process, preferably the best 

• Contact the benchmark organization, visit it, & study the benchmark activity 

• Analyze the data 

• Improve the critical process at your own organization 

Quality Problem Solving

Problem Solving

Basic steps in problem solving

• Step 1: Define the problem & establish an improvement goal

• Step 2: Develop performance measures & collect data (check sheet, scatter diagram, histogram, run chart, & control chart)

• Step 3: Analyze the problem (Pareto chart, cause-and-effect diagram)

• Step 4: Generate potential solutions (brainstorming, interviewing, surveying)

• Step 5: Choose a solution 

- Identify the criteria for choosing a solution & select the best one

• Step 6: Implement the solution

- Keep everyone informed

• Step 7 : Monitor the solution to see if it accomplishes the goal.

Total Quality Management (TQM), Basic Principles & Implementation of TQM

Total Quality Management (TQM)

A philosophy that involves everyone in an organization in a continual effort to improve quality & achieve customer satisfaction. There are three key philosophies

1. Never-ending push to improve, which is referred to as continuous improvement
2. Involvement of everyone in the organization 
3. Customer satisfaction, which means meeting or exceeding customer expectations

Hierarchy of Quality, Quality Inspection, Quality Control, Quality Assurance, Total Quality Management

Hierarchy of Quality

Follows the evolution of quality management

The Costs of Quality

The Costs of Quality

There are three cost of quality. those are

• Appraisal costs

• Prevention costs

• Failure costs

What is Quality? Dimensions & Determinants of Quality. Consequences of Poor Quality

Quality

Quality is consistent conformance to customers’ expectations, in other words, ‘doing things right’

- Major influence on customer satisfaction or dissatisfaction

Another way to think about quality is the degree to which performance of a product or service meets or exceeds customer expectations

The Dimensions of Quality

Product & service quality is often judged on eight dimensions of quality

The Determinants of Quality

The degree to which a product successfully satisfies its intended purpose

• Design

- Quality of design (Intention of designer to include/exclude feature)

• How well the product conforms to the design

- Quality of conformance (The degree to which goods/services conform to the intent of the designers)

• Ease of use

- User instructions, intended purposes, ways for functioning properly & safely

• Service after delivery

- Recall & repair of the product, adjustment, replacement or buyback

Benefits of Good Quality

• An enhanced reputation for quality

• Greater customer loyalty

• The ability to command premium prices

• An increased market share

• Fewer production or service problems 

• Lower liability costs

• Higher productivity

• Higher profits

The Consequences of Poor Quality

• Loss of business

• Liability

• Productivity

• Costs