Quality assurance is associated with some form of measurement and inspection activity. The first task we must do is produce quality merchandise so that buyers buy and keep buying.
Total quality encompasses three important aspects for managers of manufacturing and service organizations, and these are:
- Productivity Cost Cost Quality
Productivity is: the measure of efficiency defined as the quality of product achieved per unit of input or input.
Good quality increases productivity, profits, and other measures of success.
total-quality-assurance-1The Craft era: quality assurance was informal, every effort was made to ensure that quality was incorporated into the final product by the people who produced it.
Early 20th century: quality assurance fell into the hands of inspectors, work was divided into specific tasks to increase efficiency, manufacturers provided quality products but at very high prices and costs, inspection was the primary means of quality control during the middle of the 20th century.
Quality Assurance: it is about doing a statistical control, it was no longer reviewed at the end of the production line, in Honduras the companies have not yet implemented the Statistical Process Control CEP and it was eighty years ago that it was implemented for the first time in Japan.
During the Second World War the US government secretly created the MIL-STD standard military sampling tables.
After the Second World War: Due to the shortage of goods in the United States made production a top priority, quality remained within the territory of specialists. To aid Japan's reconstruction efforts, two American advisers introduced statistical quality control techniques among the Japanese.
Excellence in quality was recognized as the key to global competitiveness and was widely promoted throughout the industry.
Definition of Quality:
quality is defined:
- as a RAE degree of excellence. To make products suitable for use. Adjustment to requirements
A product is of quality when it satisfies the needs of the client.
Quality is not controlled, it is manufactured.
Quality in Design: it is not enough to control quality, quality must be designed. Quality is made in the design of the product. Quality is made in the design of processes and services.
Three Qualities Diagram
Quality of Competition: you have to see what happens on the other side, that is, the other companies to see if they can be improved. The quality is not only free, but it is a true and honest generator of profits.
Quality Dimensions:
Defined by Garvin:
- Performance Characteristics Reliability Compliance Durability Service Capacity Aesthetics Perceived Quality.
At service:
- Time Opportunity Total Courtesy Consistency Accessibility and Convenience Accuracy Sensitivity
There are three levels of Quality:
- Organizational Level. Process Level. Performer / Task.
To produce goods and services that meet or exceed expectations, a company must understand the impact of its entire system on quality.
Principles of Quality:
- Focus on the Client. Participation and Teamwork. Improvement and Continuous Learning.
There is only one true quality, one that contributes to achieving productivity, one that contributes to achieving the benefits of companies and organizations.
THE ISO 9000 STANDARDS
The word quality has been defined in many ways, but we can say that it is the set of characteristics of a product or service that give it the aptitude to satisfy customer needs.
Quality system means having a series of elements such as quality manuals, measurement equipment, procedure folders, trained personnel, etc., all working as a team to produce goods and services of the quality required by customers. The elements of a quality system must be documented in writing.
The series of ISO9000 standards are a set of statements, which specify which elements must integrate the Quality System of a company and how these elements must work together to ensure the quality of the goods and services that the company produces. Standards do not define what a company's quality system should be, but rather establish minimum requirements that quality systems must meet.
The ISO Standards related to quality are as follows:
ISO 8402: It defines terms related to quality.
ISO 9000: Provides guidelines for judiciously choosing one of the following standards
ISO 9001: Covers the quality of design, production, installation, and after-sales service.
ISO 9002: It is more restricted and covers only quality in production and installation.
ISO 9003: Still more restricted, Covers only final inspection and testing.
ISO 9004: Establishes the requirements of a quality system to obtain the guarantee of the company's security.
If a company wants to guarantee its customers quality in the stages of design, production, installation and after-sales services, it must implement a quality system in accordance with ISO 9001 (Image 1). It may happen that the company manufactures a product licensed by another firm. The quality of the design, then, does not depend on the company that manufactures but on the owner of the product. In this case, the company that manufactures can use the ISO 9002 Standard, to give its customers quality assurance in the production and installation of goods and services (Image 2). There are cases in which the company only wants to guarantee its clients the inspection and final tests of the product before its sale. This may be sufficient when the product is a raw material with minimal processing.In this case, the company can implement a quality system according to ISO 9003 (Image 3).
Important elements of the ISO 9000 Standards: Responsibility of Company Management - Quality Policy: It is the responsibility of management that the quality policy is understood and applied by all company personnel. It is required to define the roles and responsibilities of all staff regarding quality. A representative of the company's management should be appointed with the authority to implement and maintain the quality system, permanently reporting to management on its performance (Image 4). Quality System - Quality Manual: The quality system must be documented by preparing a Quality Manual. The Quality Manual must make an adequate description of the elements and procedures of the quality system and serve as a permanent reference in the implementation and maintenance of the quality system. You must explain the company's Quality Policy, the objectives to be achieved and the plan to achieve it (Image 5).
Quality in Design: Quality in design is extremely important because design defects will not be eliminated in the production stages. It is extremely important to plan the design, document the requirements that the product must meet, make plans, drawings and prototypes of the product. The design stage must provide documented information (Image 6).
Control of Documentation and Information: It is necessary to have written procedures regarding how to create and authorize the use of quality documentation, how to distribute it among the different sectors and people, how to modify it when necessary and how to withdraw the documentation. obsolete so that it is not confused with the valid one (Image 7). Purchase Control: Quality records of accepted subcontractors must be maintained. Purchases must be accompanied by documentation that describes the product, and provides data on type, grade, specifications, inspection instructions and other relevant technical data (Image 8).
Product Identification and Traceability: It is necessary to have procedures to uniquely identify all batches of the manufactured product, and all batches of the raw materials or parts used in manufacturing (Image 9).
Process Control: There must be written procedures that define how to produce, such as monitoring process parameters and criteria for task execution. And written records of the processes, equipment and qualified personnel must be kept (Image 10).
Inspection and Testing: Written procedures should be established and maintained on how to inspect and test products received from other suppliers, intermediate products that are manufactured, and final products of the manufacturing process. There must be written procedures for the inspection and testing of the products at the Receipt stage (Raw Materials and parts to be used), Manufacturing Process and Output of the Final Products (Image 11 and 12). Control of Inspection, Measurement and Test Equipment: The equipment used to carry out measurements and tests must be periodically controlled and calibrated. The uncertainty of the measuring device must also be measured, which must be compatible with the test to be performed (Image 13).
Inspection and Test Status: The inspection and test status of the manufactured batches must be properly identified (Compliant, Non-Compliant), ensuring that only approved products can be dispatched or installed (Image 14).
Control of Non-Conforming Products: Written procedures must be established regarding what is to be done with batches of non-conforming product (Image 15).
Corrective and Preventive Actions : Corrective actions are those that are executed when a nonconformity is discovered in a product or a customer complaint is filed. Preventive actions should be taken when potential causes of non-compliance are found (Image 16).
Handling, Storage, Packaging and Delivery: Written procedures must be established on how to preserve, pack and deliver the manufactured products without deterioration of their quality (Image 17).
Quality Records: All the information produced by the Quality System must be recorded (stored), either on paper or in a computer system. This information must be maintained and made available to the client (Image 18).
Internal Quality Audits: An audit is an objective examination performed by qualified people to evaluate quality systems. It is necessary to have an internal audit plan, to be carried out periodically by qualified personnel independent of the person in charge of the activity to be audited (Image 19).
Staff Training: The fundamental basis of quality is training. As good as the quality system is, if the personnel are not sufficiently trained, the system will not work (Image 20). After-Sales Services: There must be written procedures to provide after-sales services, when this is a necessary requirement (Image 21).
Statistical Techniques: The need to use statistical techniques at different stages of the production process must be identified (Image 22).
These are the elements of a quality system that ISO 9000 describes one by one. But we had said that the term SYSTEM means that they must all work together. Each element of the system must be put into operation, but it is very important that the Quality System as a whole works as an organized whole, so that the quality of the products and services that are produced can be guaranteed. (Image 23).
REENGINEERING
In the last decade the changes in the business world have been fundamental and formidable. We are witnessing the globalization of markets, the privatization and proliferation of technology and the new emphasis. Investments in technologies and development are increasingly expensive to buffer them in a single market. The increase in interdependence and productive specialization have created the products called "Without Nationality". One way to maintain and grow in this world is through reengineering.
Reengineering: It is the fundamental revision and radical redesign of processes to achieve spectacular improvements in contemporary critical performance means such as: Quality, Cost, Services and Speed.
Reengineering aims to computerize the current processes to make the fastest rather search for a new agile process that is capable of satisfying the needs of the internal or external client and for this, technology is required. Management must be willing to support all new products or processes.
Reengineering as well as Total Quality is part of the current of change that is what we must be sure will prevail in the future. Reengineering is just one method of gaining a competitive advantage. Total Quality programs work within a framework of a company's existing processes and seeks to improve them through continuous improvement.
Organizational Reengineering: During the past decade and what has run from it, the most commented topic in administration has been that of Total Quality, a topic that even today has not been fully understood and much less successfully applied. But several aspects of this movement have become clear. The focus of business activity must first be on the customer, which is why products and services only make sense if they meet your needs. Second, the competitiveness of companies is not in itself in these products and services, but mainly in the way of making or offering them, that is, in the processes that generate them. For this reason, it is imperative that the administration ceases to be function-oriented and becomes process-oriented. The third aspect,It is the need for management to include in its agenda the concept of continuous improvement, as the only way to stay competitive in a market in which the variables that affect said competitiveness permanently change.
However, the rate of competition that some companies are facing is such that continuous improvement is not enough to keep them competitive. At this point Organizational Reengineering was born, which according to the definition given by its main proponents, consists of »the fundamental review and radical redesign of processes and Organizational structure, to achieve spectacular improvements in the key measures of organizational performance, such as quality, costs, service and speed ».
Generally, after briefly knowing what it is about, many managers immediately exclaim: Ah yes; already. I've already done that. But Organizational Reengineering is not doing better what is being done, or reorganizing, or redistributing functions, or automating, restructuring, or reducing, much less, laying off people.
It is therefore about completely rethinking the way the company has been managed, changing from the principles on which the organization of work is based to the tools for the execution of tasks, through preparing employees for this change.
The new administrative order thus has, as a guiding focus, the customer; as the axis of administrative management, to processes; as an element of competitive research, Bench Marking; as raw material for decision-making and administrative work, information; as working tools, the new information technologies and as an element of definition of what to do or not to do, to the analysis of added value.
It is true, staying competitive is becoming more difficult every day. But others are already doing it.
STATISTICAL QUALITY CONTROL
The quality control statistic is based on observations, from which a function can be calculated that describes how events occur. Today they are effective tools to improve the production process and reduce its defects. It is necessary to believe that you can reduce waste and defective products. Defective products are unavoidable. The cause of all ongoing problems is variation.
In every process there are four conditions:
- Raw material. Machinery. Work method. Inspection.
The four factors are the same, the result will always be the same. All of them will be faulty or good. Changing any of the four conditions will also change the final product. Although the causes of variation in quality are innumerable, not every cause affects quality to the same degree.
There are two groups of causes:
- Cause that has a great effect Cause they have minor effects.
Statistical Methods: there are five tools that are:
- Pareto Analysis Cause and Effect Diagram Histograms Control Charts Dispersion Diagram
These are some basic tools of statistical quality control used today, it is necessary to be good in the previous tools to aspire to master more difficult and advanced methods.
Cause-Effect Diagrams: We have seen in the introduction how the value of a quality characteristic depends on a combination of variables and factors that condition the production process. We will continue with the mayonnaise manufacturing example to explain the Cause-Effect Diagrams (Image 24).
The variability of quality characteristics is an observed effect that has multiple causes. When a problem occurs with the quality of the product, we must investigate to identify the causes of it. For this we use the Cause-Effect Diagrams, also known as Fishbone Diagrams for the shape they have. These diagrams were first used by Kaoru Ishikawa.
To make a Cause-Effect Diagram we follow these steps:
- We decided which is going to be the quality characteristic that we are going to analyze. For example, in the case of mayonnaise it could be the weight of the filled jar, the density of the product, the percentage of oil, etc. We draw a thick arrow that represents the process and to the right we write the quality characteristic (Image 25). We indicate the most important and general causal factors that can generate the fluctuation of the quality characteristic, drawing secondary arrows towards the main one. For example, Raw Materials, Equipment, Operators, Measurement Method, etc. (Image 26). We include in each branch more detailed factors that can be considered causes of fluctuation. To do this, we can ask ourselves these questions:
- Why is there fluctuation or dispersion in the quality characteristic values? Due to the fluctuation of Raw Materials. Raw Materials are listed as one of the main branches. Which Raw Materials produce fluctuation or dispersion in the values of the quality characteristic? Oil, Eggs, salt, other seasonings. Oil is added as a minor branch of the main branch. Raw Materials. Why is there fluctuation or dispersion in the oil? Due to the fluctuation of the quantity added to the mixture. We add to Oil the smallest branch Quantity. Why is there variation in the added amount of oil? Due to irregular operation of the balance. The Balance branch is registered. Why does the balance work irregularly? Because it needs maintenance. In the Balance branch we place the Maintenance branch.
Thus we continue to expand the Cause-Effect Diagram until it contains all the possible causes of dispersion (Image 27).
Finally we verify that all the factors that may cause dispersion have been incorporated into the diagram. The Cause-Effect relationships must be clearly established and in that case, the diagram is finished (Image 28).
Histogram: A histogram is a graph or diagram showing the number of times each of the results is repeated when successive measurements are made. This allows you to see around which value the measurements are grouped (Central tendency) and what is the dispersion around that central value. How useful is the histogram? It allows to quickly visualize information that was hidden in the original data table. For example, it allows us to appreciate that the weight of the patients is grouped around 70-75 kilos. This is the Central Tendency of the measurements. Furthermore, we can see that the weights of all the patients are in a range from 55 to 100 kilograms. This is the Scattering of the measurements. We can also see that there are very few patients above 90 kilograms or below 60 kilograms.
Now the doctor can extract all the relevant information from the measurements he made and can use them for his work in the field of medicine (Image 29).
Pareto Diagrams: The Pareto Diagram is a special histogram, in which the frequencies of certain events are ordered from highest to lowest. Let's explain it with an example (Image 30).
Suppose a refrigerator manufacturer wants to analyze which are the most frequent defects that appear in the units when leaving the production line. For this, he began by classifying all possible defects into their various types:
| Type of deffect | Problem Detail |
| Motor does not stop | Does not stop the motor when it reaches temperature |
| Does not cool | The engine starts but the refrigerator does not cool |
| Weatherstrip Def. | Broken or misshapen weatherstrip that does not fit |
| Def paint. | Paint defects on external surfaces |
| Stripes | Scratches on external surfaces |
| It does not work | Plugging in won't start the engine |
| Door does not close | The door does not close properly |
| Drawers Def. | Interior cracks with cracks |
| Engine won't start | Engine does not start after stop cycle |
| Poor Leveling | Refrigerator sways and cannot be leveled |
| Door Def. | Refrigerator door does not close tightly |
| Others | Other Defects not included in the above |
Scatter Diagrams: Scatter Diagrams or Correlation Graphs allow studying the relationship between 2 variables. Given 2 variables X and Y, it is said that there is a correlation between the two if each time the value of X increases, the value of Y increases proportionally (positive correlation) or if each time the value of X increases, the value decreases in equal proportion of Y (Negative Correlation).In a correlation graph we represent each pair X, Y as a point where the coordinates of X and Y intersect: For example, in the following graph we can see the relationship between the content of cotton and its stretch (Image 31).
Control Charts: A control chart is a specially prepared chart or diagram where successive values of the quality characteristic being controlled are noted. Data is recorded during the operation of the manufacturing process and as it is collected.
The control chart has a Center Line that represents the historical average of the characteristic that is being controlled and Upper and Lower Limits that are also calculated with historical data.
For example, if the last 15 measurements were as follows:
So we would have a Control Chart like this (Image 32).
There are different types of Control Charts: XR Charts, C Charts, np Charts, Cusum Charts, and others. When measuring a quality characteristic that is a continuous variable, XR Charts are generally used. These are actually two charts that are used together, the one for X (subgroup average) and the one for R (subgroup range). In this case samples are taken from several pieces, for example 5 and this is a subgroup. In each subgroup the average X and the range R (Difference between maximum and minimum) are calculated.
Next we can see a typical graph of X (Image 33). And what follows is a graph of R (Image 34).
The graph of X allows to control the variability between the successive subgroups and that of R allows to control the variability within each subgroup.
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