Fundamentals of Quality

Dr. Tahseen Al-Doori 1

Fundamentals of Quality

Chapter 1


SectionsProcess BasicsDefinition of QualityThe Quality environmentTypes of QualityRelationship between Quality and costRelationship between Quality and

ProductivityBenefits of improving Quality


Definition of a Process

A process is a collection of interacting components that transform inputs into outputs toward a common aim.

Let us go through few examples of processes


Input

Component partsMachinesOperators

Customer receives product

Assembly of components into

final product

Ship to customer

Basic Process

Process

Output


Inputs

ResumeInterview

Information from references, former

employers, and schools

Employee to fill vacant position

Synthesize information

Evaluate information

Make decisionHire applicant

Hiring Process

Process Outputs

Inform personnel decision-maker of strengths and weaknesses of employee to improve future hiring efforts


Inputs

Manager dictates memo to secretary

Tells secretary to distribute it to everyone in the

organization

Employee to fill vacant position

Secretary types memo

Manager signs it

Secretary reviews employee listing to find out how many copies to

make

Secretary duplicates memo, making copies for

everyone on employee listing

Secretary distributes memo

Memo-Sending Process Process

Outputs

Responses to manager about memo


Input

Component partsMachinesOperators

Customer receives product

Assembly of components into

final product

Ship to customer

Production Process

Process Output

Information on product performance

Feedback Loop


Variation of a processThere are two types of variations that we are

interested in:1. Common Variation: Consider a process

such as getting ready for work or class in the morning.

Your process varies from day to day. This is Common variation.

2. Special Variation: if a construction project begins on highway you take to work or university

This is a special variation as it is caused by a change external to your “driving to work or university”


The Funnel ExperimentIf management tampers with a process without profound knowledge of how to improve the process through statistical thinking, they will increase the process’s variations and reduce their ability to manage that process.



Rule 1Rule 1: Set the funnel over the target at (0,0) and leave the funnel fixed through all 50 drops.This will produce a stable pattern of points on the surface as a circle Fig 1.7 below

Management’s use of rule 1 demonstrate an understanding of the distinction between special and common variation and between the different types of managerial action required for each type of variation.


Rule 2Rule 2 states that the funnel should be moved the distance (-x,-y) from its last resting point. This is an adjustment rule with a memory of the last resting point.This rule will produce a circle with diameter which will be double the variance of rule 1. As shown in Fig. 1.8 below.

Rule 2 implies that the process is being tampered with by people with inadequate knowledge of how to manage the process to reduce its variation.Rule 2 is commonly used as a method of “attempting” to make things better in a process.


Rule 2aRule 2a: states if (x , y) is within a circle centered at (0,0) with specific diameter D. do not adjust the funnel.But if (x , y) is out side the circle centered at (0,0) with specific diameter D, then use the adjustment rule specified in Rule 2.

Examples: Variance analysis Direct labor, direct materials, and overhead.

Variance analysis causes employees to react inappropriately to accounting variance.


Rule 3Rule 3: The funnel is set over the target at (0,0) prior to the initial drop.Rule 3 states that the funnel should be moved a distance (-x , -y) from the target (0,0).Therefore, it is an adjustment rule with no memory of the last resting point.This rule will produce an unstable, explosive pattern of resting points on the surface. Which will produce the Bow-tie shaped pattern as in the Fig. 1.9 below.


Rule 4Rule 4: The funnel is set over the target at (0,0) prior to the initial drop.Rule 4 states that the funnel should be moved to the resting point, therefore, it is an adjustment rule with no memory of either the last resting point or the position of the target at (0,0). This will produce an unstable, explosive pattern of resting points and moves farther away from the target (0,0) in one direction, as in the fig below

Rule 4 implies that the process is being tampered with by people with inadequate knowledge of how to manage the process to reduce its variation.It implies acting on common variation as if it were special variation.


Home Work

In the book, in chapter 1, there is “the Red Bead Experiment” PP 14.

Read the experiment and explain it in your own words.

To be handed to me next lesson Tuesday


Definition of Quality


Example

An example of the goalpost view, the desired diameter of stainless steel ball bearing is 25 mm (the nominal value). A tolerance of 5 mm above or below 25 mm is acceptable to purchasers. Thus, if a ball bearing diameter measures between 20 and 30 mm (inclusive), it is deemed conforming to specifications. If a ball bearing diameter measures less than 20 mm or more than 30 mm, it is deemed not conforming to specification, and is scrapped at a cost of $1.00 per ball bearing.

Give me more examples on Quality


Quality EnvironmentEmployees are the most critical stakeholders of an

organization. “in management, the first concern of the company

is the happiness of people who are connected with it. If people do not feel happy and can not be made happy, that company does not deserve to exist…The first order of business is to let the employees have adequate income. Their humanity must be respected, and they must be given an opportunity to enjoy their work and lead a happy life.”

Kaoru Ishikawa


Types of Quality

There are three types of Quality:1. Quality of Design or redesign2. Quality of Conformance3. Quality of Performance.


Quality of Design


Quality of Conformance


Quality of Performance


Relationship between Quality and cost


Relationship between Quality and Productivity


Benefits of Improving Quality


Documents

Fundamentals of Quality