Methodology of statistical quality control. Mechanism of statistical product quality control
Mechanism of statistical product quality control
The statistical methods applied in technological process
A role of statistical methods in management of productions
Quality of production is a set of the properties causing its suitability for satisfaction of certain requirements according to appointment. It is formed at various production phases and characterized by a number of indicators: reliability, durability, functionality, esthetics.
Qualitative production possesses high consumer properties, becomes a subject of the increased demand, fully satisfies requirements. As indicators of quality infringe on interests, both producers of production, and her consumers who can not coincide, it has to be estimated from the point of view of interests of society when the priority remains for the consumer. Society recognizes only real improvement of quality, that is realized in consumption. There is no sense, for example, infinitely to work on prolongation of functioning of one knot of the car if in general its durability does not increase because of imperfection of other knots.
It is difficult to solve a problem of improvement of quality of any type of production to the separate enterprise as have impact not only internal (intra production), but also external factors on this process, so-called "quality of society". Without improvement of all elements entering the "quality of society" block it is difficult to count on high quality of production. At the same time high-quality production guarantees success to the enterprise, and the success of the enterprise leads to success of society. This process can be presented in the form of "a quality pyramid" (fig. 1).
| Quality products (performance, design, unctional) |
| Production quality (materials, equipment, processes, employees, working conditions) |
| Quality of the company (management, organization, equipment, personnel, management) |
| Quality society (political system, science and technology, communications, spiritual, moral principles, ideals and morals, law, culture) |
Fig. 1. Quality pyramid
2 Quality as object of management
Quality management is the establishment, providing and maintenance of a necessary level of quality of production at its development, production, the address, operation and consumption which are carried out by systematic quality control and purposeful impact on conditions and factors, influencing it (State standard specification 15467-79). To operate quality - to mean to carry out the economic, organizational, technical and other actions aimed at quality providing production at all stages of life cycle of goods (introduction, growth, a maturity, demand maintenance).
In modern understanding activities for quality management cannot be effective after production is already made; it has to be carried out continuously during production, and also precede the process of production.
Quality management is based on the following principles:
- focus - it is necessary to have the accurate purpose in the quality relation;
- planned character - is planned set of actions in the field of quality, which
are subject to implementation;
- continuity;
- intensity - improvement of quality belongs to intensive factors of development
economies;
- system approach;
- complexity - the solution of problems of quality taking into account all aspects, from which
it depends;
- aspiration to exact compliance of quality to inquiries of consumers;
continuous improvement - promotes competitiveness
enterprises.
Product quality control - a production management component in general, one of its properties, functions. Therefore it develops and carried out within the operating control system and consists in development of policy in the field of quality, to accurate and well organized work on detection of demand, creation, production and service of production. This branch of science according to the general theory of management operates with concepts "system", "Wednesday", "program", etc.
Except major factors and conditions of production influence quality many random, local and subjective factors. To influence all these factors, to support an appropriate level of quality, the control system, that is set of measures of continuous impact on process of creation of a product is necessary.
Distinguish the operating and operated systems. The operated system it is presented by various levels of management of the organization, firm, other structures; the managing director - creates and provides quality management.
Let's consider the main categories of management and providing production with quality.
The control system and providing production with quality relies on the following interconnected categories: object, subject, purpose, methods, means, functions, character of the administrative relations, etc.
Object of management - quality of production, set of its properties or their some part, group, separate property. It is necessary for the effective organization of product quality control that not only the object of management was allocated, but also other categories allowing to realize and organize better all process are accurately defined.
The subject of management - the operating bodies of all steps and persons urged to provide achievement and maintenance of the planned production level of quality.
The purpose of management - a certain level and a condition of quality of production taking into account economic interests of the producer and consumer, and also safety requirements and environmental friendliness; set of properties and a level of quality which should be set, reached and provided that they corresponded to nature of requirement and thus provided production efficiency and consumption, availability of the price to the consumer, normal prime cost and sufficient profitability of production.
Methods of management of quality - ways with which governing bodies influence production, providing achievement and maintenance of the planned state and quality of production.
Methods of management of quality can be divided into four groups: organizational, social and psychological, economic, organizational and technological.
Organizational methods - set of the methods promoting such organization of the operated subsystem which will provide the demanded quality. Carry to this group of methods administrative (orders, directives, resolutions, instructions, orders), disciplinary, providing motivation (establishment of responsibility and forms of encouragement), stabilizing, based on all-organizational and linearly - a functional regulation on the basis of norms, standards, explanations, consultations, familiarization, cautions.
Social and psychological methods - set of ways of impact on spiritual interests of workers, formation of their motivations connected with ensuring the corresponding quality. Treat such methods: education and promotion of devotion to the enterprise, respect for itself as to the employee of this enterprise, pride of its achievements, forms of moral incentive.
Economic methods of management of quality - the ways of influence based on application of economic incentives and creation of a material interest in achievement of the set purpose in quality area. Also include in group of economic methods: financing of activity in the field of quality management; economic incentives of production, granting to consumers production and the services conforming to their requirements; planning of creation of the new and modernized types of production and services; pricing on production and services taking into account their level of quality; formation of funds of economic incentives of quality; use of system of compensation and material encouragement taking into account its quality on each workplace of a production system and a control system of quality in general; use of economic measures of impact on suppliers depending on quality of the services delivered by them to production and rendered.
Organizational and technological methods are subdivided into methods of quality control of process and production and methods of regulation of quality of process and production. The main place in organizational and technological methods is taken by systematic methods of management of quality.
Control facilities quality include:
office equipment, means of communication which use the governing bodies and faces operating performance of special functions in control systems of quality;
bank of the standard documentation regulating indicators of quality of production and organizing performance of special functions on quality management;
the metrological means including the state standards, measuring instruments;
the regulating documents of the state system of ensuring unity of measurements (GSI);
base of public service of standard help data on properties of substances and materials (GSSD).
The functions which are carried out by the enterprise concerning quality as object of management, following:
Rationing (standardization, certification, certification);
Technological preparation of production (sufficient logistics, high-quality seeds of plants, elite breeds of animals, high level of service, etc.);
Professional development of shots, stimulation, strengthening of responsibility for quality;
Control of the course of productions by means of information and methodological support.
The administrative relations in the field of quality are the relations of subordination (submission) and coordination (cooperation).
The relations of subordination are characterized by vertical communications of heads with subordinates and are defined by extent of centralization and decentralization of functions and problems of product quality control. At the level of the enterprise of the relation of subordination are under construction depending on its production structure and structure of a control system of quality. The administrative relations are based on a combination of one-man management, collective nature, stimulation of an initiative of members of labor collective, use of economic, moral and material incentives.
The relations of coordination are under construction by means of horizontal communications between the certain workers and the organizations entering interaction for the sake of providing a certain level of quality of production or its increase.
At the level of the enterprise product quality control can be organized by distribution of functions and tasks between divisions and workers or creations of special department of quality management. In organizational structure the divisions which are engaged in coordination of works on quality management can be provided. Distribution of functions of quality management between divisions depends on volume and nature of activity of the enterprise. In any option the head of the enterprise who is responsible for all its activity and economic results which cannot be high at bad quality of production has to perform the general management of a control system of quality.
Heads should recognize that the enterprise it is capable on bigger in comparison with last experience.
3 One of the most important stages of ensuring quality of production is high-quality management of technological processes of production. Ensuring quality of production in the course of conducting technological process is based on a monitoring procedure basis.
Control is the activity including carrying out measurements, examinations, tests or an assessment of one or several characteristics of object, in this case technological process of production and comparison of the received results with the established requirements for definition, whether compliance on each of these characteristics (ISO 8402 standard) is reached.
Control - one of the main functions of quality management. It allows to reveal mistakes in time quickly to correct them with the minimum losses.
"the feedback loop" (fig. 1) is the cornerstone of quality control.
| Sensor device |
| Process |
| Purpose |
| Mediator |
| Pathogen |
Fig 1. Feedback loop
Special type of control - test of finished goods, that is definition or use of one or several characteristics of a product under the influence of set of physical, chemical, natural and operational factors and conditions.
Formation of quality of production happens during the certain period and depends on the conditions created by technological operations of all production cycle. Control of the parameters having impact on quality of end products is especially important.
Control of technological processes and quality of production - an integral part of processes of management of quality in production. It allows to define suitability and a level of quality of production, possibility of its further use. Depending on extent of influence on technological process or production control is subdivided on active and passive.
At active control there is an opportunity to improve organizational forms or technical means for receiving quality production.
Passive control gives the chance to establish the fact: whether in the necessary limits there are physical parameters of controlled object. It is applied when it is necessary to separate qualitative raw materials from low-quality or at rejection of production. Thus step-by-step or complex control is exercised: check of physical quantity of each parameter (the maintenance of various elements in sterns, water, drains, etc.) is made on which property of this production depends.
Distinguish entrance, operational and acceptance types of control.
Entrance control is exercised at receipt of production.
Operational control is applied in productions. In the conditions of division of labor when workers are connected among themselves under the terms of production, separate deviations, mistakes reduce the general quality. At the agricultural enterprises during the working day (change) quality is controlled by workers, foremen, experts. Daily heads of divisions estimate quality of work. In crews, on farms, in shops branch groups and posts of daily control are created.
Acceptance control is exercised at delivery of production.
With complication of production the number of parameters and need for their control grows. The industry produces measuring equipment of different function. Devices of active control "warn" about deviations from the set parameters in production, and acceptance devices fix a condition of quality of already made production (grain protein content, sugar in beet, fat in milk, etc.).
Quality of goods is controlled by manufacturers, and in trade - commodity researchers at acceptance of goods from suppliers, in a storage time of goods on base, in a distribution network before realization. In many agricultural enterprises laboratories agrochemical, dairy, on quality of forages which help to improve breeding work are created, to improve technology.
Metrological ensuring quality is an establishment and application of the technical means, rules, norms necessary for achievement of unity and the demanded accuracy of measurements of volumes and quality of the performed works, the made production. Metrological providing the agricultural enterprise will be organized by laboratories of quality, engineering service of economy, control service of quality.
Deviations from requirements of the specifications and technical documentation (standards, specifications) testify to decline in quality of a product and are called as defects. Defects can be obvious, hidden, remediable and incorrigible.
The deviation of quality of production comes from the set parameters, as a rule, towards its deterioration and has the general and private manifestations.
Are among the general deviations an obsolescence, physical and an obsolescence of production, loss of initial properties at operation and storage.
Private deviations from quality are extremely various and caused by external factors: in operation violations of the rules, mistakes of developers and manufacturers, failures in production discipline, defects of the equipment, etc. The instability of quality caused by private deviations from the set parameters has casual character. Emergence of deviations can be expected only with a certain degree of probability.
Seriously instability and variability of requirements influence quality. Change of requirements of consumers even at compliance of production of standard and technical documentation worsens perception of quality or leads to its full loss.
It is possible to draw a conclusion that quality of production is in constant dynamics and is the extremely unstable category.