QUALITY CONTROL

DIPLOMA IN FOUNDRY TECHNOLOGY QUALITY CONTROL

SESSION 1 :  BASIC CONCEPTS

1.1   Quality-A Look at History
1.2   Quality – The Changing Business Conditions
1.3   “Quality” Defined
1.4   The Quality Function
1.5   Quality, Costs and Schedules
1.6   Quality Disciplines and Other Disciplines
1.7   Perspective on Quality: Internal vs. External
1.8   Summary

SESSION 2 :  THE QUALITY GURUS

2.1   Introduction

The emergence of a quality imperative is rooted in the experiences, research, writings and teachings of several pioneers and leaders of the quality movement.

As the concept of total quality continues to evolve, the contributions of others will certainly come to the forefront but for now, the work of six pioneers stands out:

–  W. Edwards Deming
–  Joseph M. Juran
–  Armand V. Feigenbaum
–  Kaoru Ishikawa
–  Philip B. Crosby
–  David Garvin
–  Genichi Taguchi

Though known as “quality gurus”, their thinking and influence is not limited to the management of quality alone. They all speak of companywide integration of purpose and high regard for the human element, as individuals and as vital components of teams dedicated to continuing improvement.

2.2   Dr. W. Edwards Deming
2.3   Dr. Joseph Juran
2.4   Armand V. Feigenbaum
2.5   Kaoru Ishikawa
2.6   Philip B. Crosby
2.7   Genichi Taguchi
2.8   David Garvin

SESSION 3 :  COMPANY WIDE ASSESSMENT OF QUALITY

3.1  Why Assessment?
3.2   Cost of Poor Quality
3.3   Categories of Quality Cost
3.4   Objectives of Evaluation
3.5   Analysis of Quality Costs
3.6   Standing in the Marketplace
3.7   Company Culture on Quality
3.8   Assessment of current Quality Activities
3.9   Summary

SESSION 4 :  QUALITY IMPROVEMENT AND COST REDUCTION

4.1     Sporadic and Chronic Quality Problems
4.2     Project-by-Project Approach
4.3     Prove the Need
4.4     Identify Projects
4.5     Breakthrough Sequence for an Individual Project
4.6     Test of Theories of Management-Controllable Problems
4.7     Test of Theories of Worker-Controllable Problems
4.8     Provide a Remedy and Prove its Effectiveness
4.9     Dealing with Resistance to change
4.10   Institute Controls to Hold the Gains
4.11    Summary

SESSION 5 :  CONTROL OF QUALITY

5.1     Definition of Control
5.2     Self-Control
5.3     The Control Subject for Quality
5.4     Measuring Actual Performance
5.5     Interpreting the Difference between Actual Performance and the Goal
5.6     Taking Action on the Difference
5.7     Summary

SESSION 6 :  SUPPLIER RELATIONS

6.1  Introduction

This step on the spiral of quality concerns the purchase of goods or services from suppliers, or vendors.

For many companies, purchases account for 60 percent of the sales rand and are the source of half of the quality problems. Poor quality of supplier items results in extra costs for the purchaser.

Current emphasis on inventory reduction provides a further focus on quality under the “just-in-time” inventory concept:

–  Goods are received from suppliers only in the quantity and at the time that they are
needed for production
–  The buyer stocks no inventories

If a portion of the purchased product is defective, production at the buyer’s plant is disrupted because of the lack of a backup inventory. With conventional purchasing, supplier quality problems can be hidden by excess inventory; with the “just-in-time” concept, it is imperative that purchased product meet quality requirements.

The interdependence of buyers and suppliers has increased dramatically.

Sometimes the interdependence takes the form of integrated facilities, e.g. a can manufacturer locates next door to a brewery; sometimes technological skills are involved, e.g. an automobile manufacturer asks a supplier to propose a design for a purchased item. The supplier becomes an extension of the buyer’s organization.

These circumstances have led to a revolution in the relationship between buyers and suppliers. In the past, the parties were often adversaries; some purchasers viewed suppliers as potential criminals who might try to sneak some defective product past the purchaser’s incoming inspection. Today, the key word is partnership, i.e. working closely together for the mutual benefit of both parties.

6.2     Scope of Activities for Supplier Quality
6.3     Specification of Quality Requirements for Suppliers
6.4     Supplier Selection
6.5     Assessment of Supplier capability
6.6     Contract Management
6.7     Supplier Certification
6.8     Summary

SESSION 7 :  MANUFACTURE

7.1     Importance of Manufacturing Planning Quality
7.2     Initial Planning for Quality
7.3     Concept of Controllability; Self-Control
7.4     Defining Quality Responsibilities on the Factory Floor
7.5    Self-inspection
7.6     Process Quality Audits
7.7     Quality and Production Floor Culture
7.8     Summary

SESSION 8 :  INSPECTION AND INSPECTION TECHNIQUES

8.1   Introduction

Prior to the industrial revolution, manufacturing industries consisted largely of small shops, each dominated by a “master”. The master trained the apprentices and supervised their work in various ways, including a form of quality control. This consisted of process surveillance and product inspection, conducted until such time as the apprentice demonstrated the capability of repeatedly turning out quality products.

As the shops grew larger, they outgrew the ability of the master to direct all affairs personally. Therefore specialized departments were created and assistants appointed to supervise these departments. One of these assistants, the shop supervisor, took over supervision of the workers and continued the tradition of personally exercising the quality controls.

In due course the number of workers grew to an extent that exceeded the capacity of the shop foreman to exercise the quality controls. This problem was solved by creating the post of inspector and delegating to the inspector the job of judging fitness for use or conformance to specification. The earliest form of this was probably in the large construction projects of antiquity. Figure 8-1 shows an inspector using a string to measure the flatness of stone blocks while a worker is engaged in dressing the stone. The date is 1450.

Figure Error! No text of specified style in document. 1: Early Inspection (1450AD)

The industrial revolution resulted in the growth of large manufacturing companies which included multiple production shops (foundry, lathe, etc.)

The word “inspection” has so many meanings that precise definition must precede any discussion. As used in this program, inspection always involves evaluating the quality of some characteristic in relation to a standard. This evaluation may be described as the inspection “act” and consists of the following actions applied to each quality characteristic:

1.   Interpretation of the specification
2.   Measurement of the quality of the characteristic
3.   Comparing 1 with 2
4.   Judging conformance
5.   Disposing of conforming cases
6.   Disposing of nonconforming cases
7.   Recording the data obtained

Every key word in the foregoing is itself subject to much variation. The word “specification” is used in the generic sense as the standard for the characteristic. It may consist of a written description, a drawing, a photograph, a physical sample, an oral instruction and a hazy memory.

The term “measurement” is used in the generic sense of evaluation, and it has its own dialect.

The main purpose of inspection is to determine whether products conform to specification. This purpose is often called “acceptance inspection” or “product acceptance”. Here we are concerned primarily with acceptance inspection.

Those engaged full time in inspection work commonly carry the title “inspector”. (The title is sometimes used to describe those who are not concerned with industrial products, processes, or services, e.g. safety inspectors, health inspectors, etc. Other titles include “tester”, “gauger” “chemist” “metallurgist,”  or “technician”. Those engaged only part time in inspection commonly carry a job title which reflects their major activities, e.g. “machine operator” “adjuster”, etc.

Since the 1960s there has been a worldwide trend toward returning some of the responsibility for product acceptance to production operators, this is known as “self inspection”.

8.2     Inspection Defined
8.3     Inspection Planning
8.4     How Much Inspection?
8.5     Aims of Inspection
8.6     Role of inspection
8.7     Inspection and Inspection Stations
8.8     The Role of the Inspector
8.9     Classes of Inspectors
8.10   Summary

SESSION 9 :  AN INTRODUCTION TO MEASUREMENT

9.1   Introduction

In modern industry, uniformity for inter-changeability of parts is vital for cost effective manufacturing. Data must be analyzed on parts and processes to determine conformance to product specifications and data must be fed back to the manufacturing process to prevent production problems.

The quantification of data on parts and processes involves:

–  The defining of standard units
–  Calibrating instruments to these standard units
–  Using these instruments to quantify parts and processes

This quantifying is called “measurement”.

9.2     Measurement Defined
9.3     Units of Measure
9.4     Measurement Standards and Traceability
9.5     Measuring Instruments
9.6     Sources of Errors in Measurement
9.7     Reducing Measurement Error

SESSION 10 :  QUALITY TOOLS

10.1   Check Sheet
10.2   Defect Location Sheet
10.3   Pareto Diagram
10.4   Cause and Effect Diagrams
10.5   Process Analysis and C&E Diagram
10.6   Run Charts

SESSION 11 :  QUALITY TECHNIQUES

11.1   Bench Marking
11.2   Using Benchmarks
11.3   The “Five Whys”
11.4   Failure Modes and Effect Analysis (FME4)
11.5   Moments of Truth (MOT)
11.6   Best Demonstrated Practice
11.7   PRE- Control
11.8   Error-Proofing the Process

SESSION 12 :  QUALITY AND WASTE ELIMINATION

12.1   The 5S‘s and Their Meaning
12.2   Purpose of the 5S’s
12.3   Kaizen
12.4   The Seven “Muda”
12.5   TQC and JIT
12.6   Quality Problem Solving

SESSION 13 :  QUALITY STATISTICS

13.1   Introduction

Statistics deals with the collection, analysis, presentation, and interpretation of quantitative data.

The purpose of statistical analysis is to derive information from raw data in order to make intelligent decisions on quality. Almost every element of an organization implementing a quality program uses statistics to analyse problems, develop solutions, and improve processes.

For example:

–  Marketing uses inferential statistics to determine the size and makeup of customer
surveys
–  Engineering uses probabilistic methods to enhance the reliability of products
–  Purchasing uses statistical analysis to evaluate and monitor suppliers
–  Quality assurance uses statistics to determine the number of products that should be
inspected
–  Manufacturing uses statistical process control to monitor production processes
–  Management uses graphic methods to display data to inform

13.2   Statistical Fundamentals
13.3   Raw Data
13.4   Interpretation of Graphs
13.5   Measures of Central Tendency
13.6   Measures of Dispersion
13.7   Common Distribution Shapes
13.8   Normal Distribution

SESSION 14 :  STATISTICAL QUALITY CONTROL CHARTS

14.1   Introduction

We can define statistical process control (SPC) as the application of statistical methods to the measurement and analysis of variation in any process.

A process is a unique combination of machines, tools, methods, materials, and people that attains an output in goods, software, or services.

The evidence is clear that these fascinating techniques can make an important contribution to achieving quality objectives. For most organizations, these techniques are essential. To help assure successful and continued application of these concepts in the reality of lean operating budgets, these techniques must not become an end in themselves. Pragmatic operating managers correctly demand that each potential application show a tangible opportunity for significant benefits.

14.2   Statistical Control Charts
14.3   Advantages of Statistical Control
14.4   Principal Kinds of Control Charts
14.5   & R Charts
14.6   & R Chart Patterns
14.7   Control Charts for Attributes

SESSION 15 :  ACCEPTANCE SAMPLING INSPECTION

15.1   Introduction

Acceptance sampling is the process of evaluating a portion of the product in a lot for the purpose of accepting or rejecting the entire lot.

The main advantage of sampling is economy. Despite some added costs for designing and administering the sampling plans, the lower costs of inspecting only part of the lot result in an overall cost reduction.

In addition to this main advantage, there are others:

–  The smaller inspection staff is less complex and loss costly to administer
–  There is less damage to the product, i.e., handling incidental to inspection is itself a
source of defects
–  The lot is disposed of in shorter (calendar) time so that scheduling and delivery
are improved
–  The problem of monotony and inspector error induced by 100 percent inspection is
minimized
–   Rejection (rather than sorting) of nonconforming lots tends to dramatize the quality
deficiencies and to urge the organization to look for preventive measures
–  Proper design of the sampling plan commonly requires study of the actual level of quality
required by the user. The resulting knowledge is a useful in put to the overall quality
planning

The disadvantages are:

–  sampling risks
–  greater administrative costs
–  less information about the product than is provided by 100 percent inspection

Acceptance sampling is used when:

1.   The cost of inspection is high in relation to the damage cost resulting from passing a
defective product
2.   100 percent inspection is monotonous and causes inspection errors
3.   The inspection is destructive

Acceptance sampling is most effective when it is preceded by a prevention program that achieves an acceptable level of quality of conformance.

There is a need to emphasize what acceptance sampling does not do. It does not provide refined estimates of lot quality. (It does determine, with specified risks, an acceptance or rejection decision on each lot.) Also, acceptance sampling does not provide judgments on whether or not rejected product is fit for use. (It does give a decision on a lot with respect to the defined quality specification.)

In recent years, the emphasis on statistical process control has led some practitioners to conclude that acceptance sampling is no longer a valid concept. Their belief, stated here in oversimplified terms, is that only two levels of inspection are valid – no inspection or 100 percent inspection.

Our viewpoint is that the concept of prevention (using statistical process control and other statistical and managerial techniques) is the foundation for meeting product requirements. Acceptance sampling procedures are, however, important in a program of acceptance control. Sampling procedures are continually matched to process history and quality results. This ultimately leads to phasing out acceptance sampling in favour of supplier certification and process control.

15.2     General Sampling Procedure
15.3     Sampling Planning
15.4     Sample Selection
15.5     Acceptance of Individual Items and Acceptance of the Mass
15.6     Operating Characteristic of Single Sampling Plans
15.7     Average Outgoing Quality Limit
15.8     Single, Double, Multiple and Sequential Sample Plans
15.9     MIL-STD-105B
15.10   Other Types of Sampling Plans