Total Quality Management

MANAGEMENT OF PROCESS QUALITY

CHAPTER 6

Introduction

The management of process quality category examines systematic processes the company uses to pursue ever-higher quality and company operational performance.

The key elements of process management are examined, including research and development, design, management of process quality for all work units and suppliers, systematic quality improvement and quality assessment.

Introduction It is apparent that this definition is directly

related to how well the processes are managed – all of the processes in the organization that contribute directly or indirectly to quality as the customer defines it.

The concept is illustrated in a figure. The control component (quality assurance) has moved from measuring output (the traditional control system) to controlling the continuous improvement of the process.

History of Quality Control

Historians have traced the concept as far back as 3000 BC in Babylonia.

Among the references to quality from code of Hammurabi, ruler of Babylonia is the following excerpt: “The mason who builds a house which falls down and kills the inmate shall be put to death” This law reflects a concern for quality in antiquity.

History

Process control is a concept that may have begun with pyramids of Egypt, when a system of standards for quarrying and dressing of stone was designed. One has to only examine the pyramids at Cheops to appreciate this remarkable achievement. Later Greek architecture would surpass Egyptian architecture in the area of military applications.

History Centuries later, the shipbuilding operations in

Venice introduced rudimentary production control and standardization.

Following the Industrial Revolution and the resulting factory system, quality and process control began to take on some of the characteristics that we know today. Specialization of labor in the factory demanded it. Interchangeability of parts was introduced by Eli Whitney when he manufactured 15,000 muskets for the federal government.

History

This event was representative of the emerging era of mass production, when inspection by a skilled craftsman at a workbench was replaced by the specialized function of inspection conducted by individuals not directly involved in the production process.

History Specialization of labor and quality assurance

took a giant step forward in 1911 with the publication of Frederick. W.Taylor’s book principles of scientific management. This pioneering work had a profound effect on management thought and practice. Taylor’s philosophy was one of extreme functional specialization and he suggested eight functional bosses for the shop floor, one of whom was assigned the task of inspection:

History

The inspector is responsible for the quality of the work and both the workmen and the speed bosses (who see that the proper cutting tools are used, that the work is properly driven and that cuts are started in the right part of the piece) must see that the work is finished to suit him. This man can of course, do his work best if he a master of the art of finishing work both well and quickly.

History

Taylor later conceded that extreme functional specialization has its disadvantages, but his notion of process analysis and quality control by inspection of the final product still lives on in many firms today. SQC the forerunner of today’s TQM or total quality control, had its beginnings in mid-1920s at the Western Electric plant of the Bell system.

History Walter Shewhart, a Bell Laboratories physicist,

designed the original version of SQC for the zero defects mass production of complex telephone exchanges and telephone sets.

In 1931, Shewhart published his landmark book Economic Control of Quality of Manufactured product. This book provided a precise and measurable definition of quality control and developed statistical techniques for evaluating production and improving quality.

History During World War II, W.Edwards Deming and

Joseph Juran, both former members of Shewhart’s group separately developed the versions used today.

It is generally accepted today that the Japanese owe their product leadership partly to adopting the precepts of Deming and Juran. According to Peter Drucker, US Industry ignored their contributions for 40 years and is only now converting to SQC.

History

The Willimatic Division of Roger Corporation and IBM supplier uses just-in-time techniques along with X-bar and R-charts for key product attributes to achieve statistical process control. Rework is reduced by 40 percent, scrap by 50 percent and productivity is increased by 14 percent.

Product Inspection Vs. Process Control

If you can’t measure it, you can’t manage it. The popularity of the expression usually means

that there is a measure of truth behind it. Truism in the field of quality management include “don’t inspect the product, inspect the process” and “you can’t inspect it in, you’ve got to build it in”

There is sound thinking behind these two statements.

Product inspection Vs.Process Control Process begins with the concept of the product idea

and extend through the life cycle of the product to ultimate maturity and phase out.

It is clear that in the philosophy of TQM most business functions and activities (processes) are interrelated and none stand alone – not purchasing, engineering, shipping, order processing or manufacturing. Key business objectives and organization success are dependent on cross-functional processes. Moreover these processes must change as environments change.

The conclusion emerges that true process optimization requires the application of tools and methods in all activities, not just manufacturing.

Historically there have been two major barriers to effective process control. The first has been tendency to focus on volume of output rather than quality of output.

The second one being, quality control system that measures products or service against a set of internal conformance specifications that may or may nor relate to customer expectations.

The result in many cases has been inferior quality products that are reworked or scrapped or worse, products that customers did not buy.

Bytex Corporation Manufactures electronic matrix switches for Citicorp, MasterCard, American Express and others. The company has focused on understanding the process, concentrating on eliminating value-added transactions. Cycle time is down by 60 per cent, inventory down by 43 per cent, final assembly time down by 52 per cent and floor space down by 30 per cent. The resulting product is superb.

Moving from inspection to process control

The objective is not merely to discover defects, but rather to identify and remove the causes of defects or variations.

Process control now becomes problem solving for continuous improvement.

Moving from inspection to process control takes place in steps. They are as follows:

Process characterization – definition of process requirements and identification of key variables

Develop standards and measures of output – involve work force

Monitor compliance to standards and review for better control – identify any additional variables that affect quality

Identify and remove causes of defects or variations (this requires a step-by-step documentation of the process and process control sharing)

Achievement of process control with improved stability and reduced variation.

Statistical Quality Control

This is the oldest and most widely known of the several process control methods.

It involves the use of statistical techniques such as control charts to analyze a work process or its outputs.

The data can be used to identify variations and to take appropriate actions in order to achieve and maintain a state of statistical control and to improve the capability of the process.

Rigorously applied, SQC can virtually eliminate the production of defective parts.

By identifying the quality that can be expected from a given production process, control can be built into the process itself.

Despite the maturity of the method and its proven benefit, many firms do not take full advantage of it. One survey found that 49per cent of responding electronic manufacturers reported using SQC techniques, but 75 per cent of them also continued to use traditional 100 % inspection.

At Motorola, SQC has been integrated into the corporate culture and is being applied in all areas of the plant. Steps to place a process under statistical control include (1). Characterizing the process 92). Controlling it and (3) adjusting the process when non-random deviations are observed. Six Sigma is the goal.

Approaches to SQC

SQC and SPC were developed in the United States in the 1930s and 1940s by W.A.Shewhart, W.E.Demming, J.M.Juran and others. These techniques have been used for decades by some American firms and many Japanese companies. Despite the proven effectiveness of the techniques, many U.S. firms are reluctant to use them.

The approach is designed to identify underlying cause of problems which cause process variations that are outside predetermined tolerances and to implement controls to fix the problem. The basic approach contains the following steps:

Awareness that a problem exists Determine the specific problem to be

solved Diagnose the causes of the problem Determine and implement remedies to

solve the problem Implement controls to hold the gains

achieved by solving the problem.

Tools for SQC

Process improvement depends to a large extent on the gathering and analysis of data which are abundant in any organization that is involved in process problems. The basic techniques are:

Data Collection Data Display Problem Analysis

Data Collection

A check sheet is an aid used in assembling and complying data concerning a problem. It is used to collect data on a process in order to determine whether any unusual or unwanted elements are present. The functions of the check sheet are

Production process distribution checks

Defective item checks Defective location checks Defective cause checks Checkup confirmation checks At the National machine tool company a team

(quality circle) identified the problem as “loss of time due to reworked jobs” and agreed that in order to determine the causes of the problems it would be necessary to find out which departments were experiencing excessive rework.

As a result, data were collected and recorded on the check sheet. It was obvious from the check sheet that department number 55 has excessive rework.

Data Display After data are collected, they can be converted

into a variety of forms for display and analysis. The control charts reflects the ongoing control of

process and signals an alarm when the process exceeds control limit.

A bar graph or column graph summarizes and presents data in an easily understood manner.

A scatter diagram depicts the relationship between two kinds of data, and the relationship forms a pattern.

A histogram is a vertical bar graph showing the distribution of data in terms of the frequency of occurrence for specific values of data.

A pareto diagram is the most widely used statistical tool in problem analysis. Indeed, it is almost universal, in process control problem solving. It is a graphic way of summarizing data in order to focus attention on the main reasons why some result in occurring and to produce a cause-and-effect relationship.

Problem Analysis The cause and effect diagram is sometimes

known as the “fishbone” or “Ishikawa diagram”, it was developed by Professor Kaoru Ishikawa of the University of Tokyo in 1950.

It is an excellent tool for organizing and documenting potential causes of problems in all areas and at all levels in the organization. As a brainstorming device it is a good way to stimulate ideas during problem solving meetings.

The diagram is a guide for discussion and focuses on the subject at hand. It serves as a measure for progress and indicates how far the discussion has progressed.

By encouraging group members to participate, it becomes an educational tool. Knowledge is also shared.

It encourages data gathering. Examination of the causes of problem leads to the gathering of additional data in order to support and validate the causes.

Pareto Analysis

Dr.J.M.Juran popularized the term “the pareto principle” while teaching quality control methods to the Japanese following World War II. This process is derived from Pareto’s Law named for the Italian economist Alfredo Pareto. The concept of the law is that any cause that results from a multiplicity of effects is primarily the result of the impact of a minor percentage of all the causes.

This technique is similar to 80-20 rule: 80 percent of inventory value is in 20

percent of the inventory items. 80 percent of the sales volume comes

from 20 percent of the customers 80 percent of the overdue accounts are

owed by 20 percent of the customers.

Quality Function Deployment

If quality definition (customer expectation) is not introduced early in the concept or design stage, there is risk that design errors and product defects will only be discovered at later stages of production or final inspection.

Motorola estimates that while design accounts for only 5 per cent of product cost, it accounts for 70 percent of the influence on manufacturing cost.

QFD

It suggests that this method has the potential to achieve many of these requirements.

In Japan where the method was first used, companies have achieved dramatic improvement in the design development process, including reductions of 30 to 50 per cent in engineering changes and design cycle time and 20 to 60 percent in start-up costs.

Steps in QFD Step 1 – Product Planning – Begins with defining

the customer requirement about the desired product characteristics

Step 2- Prioritize and Weight, the relative importance that customers have assigned to each characteristic

Step 3 – Competitive Evaluation, for those who want to be world-class or meet or beat the competition, it is essential to know how their products compare, to give competitive advantage.

Step 4 – Design Process, this is where the customer’s product characteristics meet the measurable engineering characteristics that directly affect customer perceptions

Step 5 – Design a matrix indicating the degree to which each engineering characteristics affects the customers’ characteristics is designed.

Step 6 – Design, the matrix by allowing the changes in step 4 and 5 and do some trade-offs

Step 7 – Process Planning, output from the design process goes to process planning, where the key process are determined

Step 8 – Process Control, output from step 7 goes to process control, where the necessary process flows and controls are designed.

Just-In-Time (JIT) By the third year of JIT implementation, Isuzu ( a

Japanese company) had reduced the number of employees from 15,000 to 9,900, reduced work-in-process from 35 billion yen to 11 billion yen and decreased the defect rate by two-thirds.

HP has spread JIT to all areas, including cost accounting, procurement and engineering. At one plant 290 pieces of equipment are hand assembled, product reliability has improved six fold and productivity is up.

US manufacturing has been characterized by mass production, high-volume output, and machine capacities that are pushed to the limit. This is changing as American Managers begin to discover a production method called Just-In-Time (JIT).

JIT is a basic component of manufacturing strategy. The expense and risk of maintaining inventory can be reduced so that lower costs becomes a way of improving both productivity and quality.

Just-In-Case (JIC)

JIC involves the use of buffer or safety stocks. Reasons for the need of buffer stock is that avoids risks of stock outs or failure of suppliers, getting a better price for volume purchasing or avoiding an anticipated price increase.

Shigeo shingo, who is credited with designing Toyota’s JIT production system believes that the “push” process in the US generates process-yield imbalances and interprocess delays.

Kanban as JIT is called in Japan, means visible record. It is a means of pulling parts through the assembly process; production is initiated only when a worker receives a visible cue that assembly is needed for the next step in the process.

Benefits of JIT

JIT is not an inventory control method. It is a system of factory production that interrelates with all functions and activities. The benefits include:

Reduction of direct and indirect labor by eliminating irrelevant activities

Reduction of floor space and warehouse space per unit of output

Reduction of setup time and schedule delays as the factory becomes a continuous production process

Reduction of waste, rejects and rework by detecting errors at the source

Reduction of lead time due to small lot sizes, so that downstream work centers provide feedback on quality problems.

Better utilization of machines and facilities Better relations with suppliers Better plant layout Better integration of and communication

between functions such as marketing, purchasing, design and production

Quality control built into the process