Technical control is ... Objects of technical control

The competitiveness of any enterprise depends on the quality of its products. Its high level can be ensured only if there is a well-coordinated organization of enterprise services and when using modern tools of a quality management system. Technical control is one of the main components of quality management. Its main task is to prevent the release of products that do not comply with technical and regulatory documentation. This process largely depends on the organization of control work.

The concept of technical control

Product quality control is used to assess the qualitative and quantitative indicators of the manufactured goods or services. Technical control is a check that covers all stages of the product life cycle, starting from the receipt of raw materials (input) at the enterprise and ending with the shipment of finished products. In this regard, they also distinguish production, which covers all technological operations and consists of the following types:

• input (raw materials and components);
• operating;
• technological discipline;
• acceptance (quality, completeness, marking);
• technological equipment;
• production conditions and other factors affecting the quality of the finished product.

Technical control is a check for compliance with established requirements. A similar procedure is carried out in 3 stages:

• Carrying out measurements, collecting other information about the controlled object.
• Processing of the obtained data, their comparison with standard values.
• Development of corrective measures to eliminate inconsistencies.

The general purpose of these works is to find marriage - correctable or final. Its criteria are the presence of defects - deviations from the normative and technical documentation (NTD). Their occurrence requires an analysis of the causes and conditions, as well as a solution to the issue of stopping production and a way to fix the marriage.

The most common causes of defects are violation of design and technological requirements, errors made during the design process, failure to perform control operations, and equipment wear. Therefore, improving quality is closely related to improving the production culture, qualifications and personal responsibility of workers.

The technical control system includes:

• objects and methods of control;
• performers;
• technical documentation.

During the control operation, samples are also used. These are units of the evaluated object or its parts, the characteristics of which are taken as the basis for high-quality manufacturing.

Types of control

Technical control is a concept that has many classification features. The types of control are grouped as follows:

Types of technical quality control are regulated by design and technological documentation (KTD), methods, standards approved by the enterprise and other scientific and technical documentation. Their choice depends on the serial production.

There is also the concept of technological and technical supervision - control, which is carried out by the customer in the process of production work. Most often, this type of verification is carried out in construction.

Methods

Technical control methods include several components:

• measurement technology;
• list of evaluated features;
• means of control;
• regulated accuracy.

Product quality control is carried out in the following main ways:

• visual inspection, checking for the absence of external defects;
• shape and size measurements;
• hydraulic, pneumatic, and mechanical tests for tensile, compression, strength, and to determine other physical characteristics;
• chemical, metallographic and other types of laboratory tests;
• X-ray, luminescent, electrophysical, electrothermal, ultrasonic and other special methods;
• sampling from test materials;
• carrying out control tests of prototypes, batches of products or products of unit production;
• verification of compliance with technological discipline in production.

In recent years, non-destructive testing methods (acoustic, fluoroscopic, capillary, magnetic, eddy current and others) have been widely developed in the organization of technical control, which provide a higher economic effect and allow expanding the capabilities of such an operation.

Statistical evaluation

The technical control system includes the analysis of a large array of measured parameters. They do not have an identical character, their values ​​fluctuate within certain limits, since the errors of the technological process have random fluctuations. When conducting technical control, the following basic statistical methods for assessing quality are used:

• stratification;
• cause and effect diagrams;
• Pareto charts;
• histograms;
• control cards.

In practice, several methods are usually used simultaneously, which allows you to get more useful information to analyze the causes of marriage.

Stratification method

The method of separation is one of the simplest. Its principle is to group the measurement data (according to the conditions for their receipt, for example, by contractor, equipment, technological operation and other parameters) and the processing of each set separately.

If a difference is found between the stratification parameters, then this allows us to determine the cause (human factor, equipment errors, and others). A similar method of statistical analysis is used both independently and in combination with other methods.

Causal relationship diagram

A causal diagram is used to identify and systematize factors that influence the appearance of defects, and is constructed in the following order:

• choose a problem to find its solution;
• determine the maximum number of factors affecting the controlled parameter;
• identify the most significant factors and conditions;
• determine the reasons that affect them;
• analyze the chart (brainstorming is recommended);
• Develop an action plan.

If factors can be quantified, then they are analyzed using Pareto diagrams. For complex schemes, the method of separation by individual significant factors is used.

Pareto Chart

Pareto diagrams are used to illustrate the relative importance of various causes of defects. Those that have the largest percentage are subject to priority elimination.

Such charts are also built before and after the corrective measures taken to evaluate their effectiveness. They are a graph with columns corresponding to the factors of marriage. The height of the columns is equal to the relative share in the total number of defects. On their tops build a cumulative curve.

bar graph

The histogram is also made in the form of a bar graph, but the height of the column in this case reflects the amount of data falling into this range of values ​​of the controlled parameter. For example, on the abscissa axis, the intervals of the scatter of the diameter of the neck of the shaft are plotted, and on the ordinate axis, the number of parts from the batch having this size. Thus, the histogram shows the size distribution for one of the technological operations or for final acceptance.

On the obtained columns draw an approximating line. According to this schedule, the reasons for the size exceeding tolerances are analyzed. If the distribution curve has two vertices, then this indicates the combination of two factors in the diagram.

Control cards

The basis of the control chart method is mathematical probability theory. When building maps, the following parameters are determined:

• boundaries for the statistical evaluation of the measured value;
• sampling frequency and volume;
• actions to be taken when debugging a process.

Most technological processes are described by the law of the normal Gaussian distribution, shown in the figure below.

Objects, goals and objectives

Technical control is one of the components of quality management. At each stage of the product life cycle, there is a specificity of its implementation. The goals, objectives and objects of technical control at each of these stages are:

State Technical Control

State control is a form of verification of compliance of organizations with the technical regulations. It can be carried out both by state organizations and non-state ones (the right to carry out such work is enshrined in licenses). Most often, such checks are carried out by enterprises in the energy industry and the production of measuring instruments.

The main goal of state control is to prevent cases of unfair treatment of consumers by manufacturers, sellers and suppliers of goods and services. Moreover, the activities of the inspection organization can be expressed in several forms:

• verification of the certificate of conformity, indicating compliance with the requirements of national, international, industry and other standards;
• issuing instructions to eliminate violations identified during the audit;
• suspension or termination of the certificate of conformity;
• holding a producer or supplier criminally and administratively liable.

Quality control

To organize technical control at enterprises, they create a quality service. It consists of several departments. Its structure may include the following units:

• bureau of entrance control;
• workshop bureaus of technical control;
• central factory laboratory;
• standardization bureau;
• Bureau of metrological support;
• measuring and testing laboratory and other structural units.

The Department of Technical Control and Quality Assurance is headed by the Director of Quality. The regulation on this unit is approved by the general director of the organization, and the activity of this structure should be regulated by the enterprise standards adopted in the established manner.

The technical control service works closely with such departments as:

• chief designer (joint development of test methods, product and component quality requirements);
• chief technologist (routings with requirements for conducting control operations, joint verification of compliance with technological discipline);
• chief mechanic (for ensuring accuracy of equipment);
• personnel (selection of personnel of the necessary qualifications);
• supply (incoming control);
• financial services (analysis of losses due to marriage and expenses to prevent it);
• production units.

The coordination of the activities of these services, the formulation of the main tasks to achieve quality, as well as the final decision are made by the chief engineer of the enterprise.