Methods for quantitative assessment of product quality.

Topic 5.6 Organization of technical control of product quality


1. The concept of product quality and its indicators

2. Concept, tasks and objects, types, methods of control

3. The concept and methods for assessing the technical level of products

4. Conformity assessment of product quality. Certification.

The concept of product quality and its indicators

Product quality is a set of product properties that determine its suitability to satisfy certain needs in accordance with its purpose.

Product quality indicator – a quantitative characteristic of one or more product properties that determine its quality.

To assess the quality of products, a system of indicators is used, which includes the following groups.

1. Generalizing , characterizing the general level of product quality: the volume and share of progressive types of products in the total output, grade (brand) of products (in light, cement industries), economic effect and additional costs associated with improving quality.

2. Complex , characterizing several properties of products, including the costs associated with development, production and operation. Each industry sector has its own specific complex indicators. For example, in the bearing industry, there may be an indicator that reflects the service life of bearings (in hours) and the cost of their manufacture or price (in rubles):

P to u003d Service life / Cost price (price)

A complex indicator of quality, for example, of an electric motor, is determined by the ratio of the amount of useful mechanical energy generated by the engine over its entire service life to the total costs for the production and operation of the engine.

3. Single , characterizing one of the properties of the product. They are divided into indicators:

Name of indicator Content Meter
1. Purpose (performance, power, speed) They characterize the technical and operational properties of the consumer. output per unit of time.
2. Reliability Ability to operate without failure under normal operating conditions. Time to failure.
3. Maintainability The suitability of the product for maintenance and repair. Downtime for repairs.
4. Durability The ability of a product to maintain its properties within specified limits for a certain time. Service life repair costs.
5. Manufacturability (material consumption, labor intensity) Consumption of materials per unit of production. Labor costs per unit of output. The share of material or labor costs in the cost of production.
6. Grading Gradation of products according to one or more indicators, established by regulatory documentation. grade factor.
7. Environmental The content of harmful impurities. The percentage of harmful impurities.
8. Aesthetic Design, finishing, style and fashion.

Concept, tasks and objects, types, methods of control.

Technical control of production and product quality – a set of methods, means and measures by which the quality of raw materials, materials and finished products is verified with the requirements of standards, and the parameters of the technological process are compared with the approved regulations.

Control tasks:

– prevention of marriage;

— ensuring the level of product quality established by the standards;

— registration of marriage and analysis of its causes;

– development and implementation of measures to improve product quality;

— improvement of control methods.

Objects of control:

— initial raw materials and materials;

— technical orientation according to which the products are manufactured;

— quality of instrumentation;

— condition of the equipment;

— technological regimes and processes;

– semi-finished products;

– finished products;

– packaging and shipment;

– operation of the product at the consumer.

Types of control:

Classification sign Type of control
1. By the stages of the production process 2. By the completeness of coverage of the objects of control 3. By the place of execution 4. By the possibility of using products after control 1. Input 2. Operational 3. Acceptance (delivery) 1. Continuous 2. Selective 1. Stationary 2. Sliding 1. Destructive 2. Non-destructive

Methods for quantitative assessment of product quality.

The product quality control process consists of determining the quantitative value of the controlled parameter and comparing it with the established standard or other normative value.

Methods for quantitative assessment of product quality are studied by a special science – qualimetry. Quantitative values of product quality indicators are determined by:

one. experimental method , based on the use of technical means. It allows you to give the most objective quantitative assessment of quality, since it is based on physical experiments – metrology methods (measurement of geometric dimensions, mass, hardness, electrical conductivity, wear resistance, etc.);

2. organoleptic method , based on the determination of quality by the relevant specialists using the senses according to the point system (measurement of taste, smell, color);

3. sociological method based on the use of accounting data and analysis of product consumers;

4. expert method based on the use of generalized experience and intuition of specialists and consumers of products

The listed methods provide 100% coverage of controlled objects. However, it often turns out to be expedient to check only a part of controlled objects. In this case, statistical control methods are applied.

5. Statistical method of control means quality control of products or the state of the technological process, carried out using the theory of probability and mathematical statistics.

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