In a broad sense, quality control is the sum of all measures to ensure a stable level of quality of manufactured products. In a narrow sense, this term means a comparison of the actual value of a product with a given value, in which it is established to what extent the products satisfy the requirements established for them.
Quality Control- any planned and systematic activity carried out on manufacturing plant(in a production system), which is implemented to ensure that the goods, services, and processes produced meet the established customer requirements (standards).
In accordance with the ISO 9000:2000 standard, which defines all such standards, quality is a set of certain characteristics and properties of a product or service to satisfy specified needs. This definition turns quality into a value-neutral list of product characteristics (see Diagram 1). It is important that the selected characteristics are measurable and controllable. These may include physical quantities (weight, temperature, density), as well as characteristics relevant to trade (price, quantity per lot, package size) or to customers (for example, positive consideration of wishes). Characteristics can be very different, two main subgroups are qualitative (for example, design) and quantitative (stroke height), each of which can be determined either precisely (for example, the press piston stroke is exactly 150 mm) or have a certain interval (the press piston stroke installed in the range from 20 to 100 mm). In addition, there may be tolerances (150 mm plus minus 0.1 mm).
Diagram 1. Example of a quality concept for a connecting hose.
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Quality parameter |
Requirements |
Quality standard |
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max.507 mm - min. 497 mm |
|||
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Diameter |
Internal diameter di= 9 mm, External diameter d a = 16 mm |
Max. 507 mm - min. 497 mm Max. 8.4mm - min.7.4mm |
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|
Outer surface color |
We accept different colors |
Set value |
|
|
Bend radius |
Smallest bending radius 65 mm |
Not less than 65 mm |
|
|
Operating pressure |
Quality control includes both design (design) control and manufacturing inspection, which may differ in the volume of control activities carried out during continuous control and the sample size during selective control. Sampling control (statistical) gives indications about the state of the production process either using statistical methods (production control) or using data obtained on the proportion of defective products in the volume of the production batch.
Types of quality control
Thus, a distinction is made between sample, continuous and statistical types. Solid All products undergo inspection; production records are kept of all defects that arise during the manufacturing process of the product.
Selective— control of a part of the product, the inspection results of which apply to the entire batch. This type is precautionary, from here it is carried out throughout production process in order to prevent marriage.
Incoming control— checking the quality of raw materials and auxiliary materials entering production. Constant analysis of supplied raw materials and supplies allows us to influence the production of supplier enterprises, achieving improved quality.
Interoperational control covers the entire technological process. This type is sometimes called technological, or current. The purpose of interoperational control is to check compliance with technological regimes, rules of storage and packaging of products between operations.
Output (acceptance) control— quality control of finished products. The purpose of final inspection is to establish compliance of the quality of finished products with the requirements of standards or technical specifications, and to identify possible defects. If all conditions are met, then delivery of the product is permitted. The quality control department also checks the quality of packaging and the correct labeling of finished products.
7 instruments
The following quality control tools are available ( ):
- Summary map of defects;
- Bar chart;
- Quality regulation card;
- Brainstorm;
- Correlation diagram;
- Pareto chart.
Closely related to the technically oriented quality control is the economically oriented approach. Technical specifications should never be considered separately from economic ones. Technological innovation occurs exactly where economists see good opportunity cost reductions or great potential for increased profits. The potential for improvement can only be assessed when a clear economic analysis is available together with the technical data. The international standard ISO 9000:2000 defines quality costs as “the costs incurred to ensure the desired quality and to convince the consumer that the product will satisfy his needs, as well as losses from insufficient quality.” Diagram 2 gives an idea of how they are divided:
Scheme 2. Structure and classification of quality costs
The cost of a defect is determined by whether it was discovered in production or a consumer complaint. Typical internal costs of marriage are:
- waste, defective products;
- recycling of defects;
- unplanned sorting;
- research of the problem;
- repeated inspections;
- additional time costs due to the need for unforeseen control.
Typical external costs of marriage are:
- costs of replacing defective goods
- maintenance and repair of defective goods
- expenses arising from the provision of a guarantee
- cost of product warranty.
In most cases, it makes sense to divide the costs of defects into the costs of identifying defects, the costs of eliminating defects, and the costs that resulted from defects.
The costs of conformity include the costs necessary to achieve compliance between the planned and existing quality; certification costs include all costs associated with documenting activities. These include costs for certification of quality management systems or costs for software that facilitates the distribution of documents throughout the enterprise. Control costs usually mean the costs of carrying out control activities before the start, during production and control of finished products, as well as the costs of all other quality control tools. This may also include external costs for providing guarantees, obtaining permits, etc. The costs of preventing defects include planning, performance research, supplier assessment, auditing, and staff training. This also includes production maintenance costs.
Practical examples of the use of quality control can be found in Almanac "Production Management"
NON-STATE EDUCATIONAL INSTITUTION OF HIGHER PROFESSIONAL EDUCATION
"YELABUGA CITY INSTITUTE OF INNOVATIVE TECHNOLOGIES"
Faculty of Engineering and Technology
Department of Quality Management
in the discipline: “Means and methods of quality management”
on the topic: “Incoming product quality control”
Yelabuga 2011
Introduction
Concept and types of product quality control
Incoming product quality control, definition, concept of purpose, main tasks, organization of incoming control, efficiency
Conclusion
Introduction
Relevance. Quality control is one of the main functions in the quality management process. This is also the most comprehensive function in terms of the methods used, which are the subject of a large number of works in different fields of knowledge. The importance of control lies in the fact that it allows you to identify errors in time, so that you can quickly correct them with minimal losses.
The purpose of this work is to consider quality control, as well as to define the concept of incoming product quality control, its purpose, main tasks, organization of incoming control and efficiency.
The test consists of an introduction, 4 chapters, a conclusion, where all the conclusions of the work and a list of references are summed up.
The first chapter discusses the concept and types of product quality control. The second chapter discusses incoming product quality control, definition, concept. The purpose, main tasks, organization and effectiveness of incoming product quality control are discussed in the third chapter. And how incoming quality control of metal products is carried out at enterprises is discussed in the fourth chapter.
quality control standard metal products
1. Concept and types of product quality control
Quality control means checking the compliance of the quantitative or qualitative characteristics of a product or process on which the quality of the product depends with established technical requirements.
Product quality control is integral part production process and is aimed at checking reliability during its manufacture, consumption or operation.
The essence of product quality control at an enterprise is to obtain information about the condition of the object and compare the results obtained with the established requirements recorded in drawings, standards, supply contracts, technical specifications. NTD, TU and other documents.
Control involves checking products at the very beginning of the production process and during operational maintenance, ensuring in case of deviation from regulated quality requirements, taking corrective measures aimed at producing products of adequate quality, proper maintenance during operation and full satisfaction of consumer requirements. Thus, product control includes such measures at the place of its manufacture or at the place of its operation, as a result of which deviations from the norm of the required level of quality can be corrected even before defective products or products that do not meet technical requirements are released. Insufficient control at the stage of manufacturing serial products leads to financial problems and entails additional costs. Quality control includes:
incoming quality control of raw materials, basic and auxiliary materials, semi-finished products, components, tools arriving at the enterprise’s warehouses;
operational production control over compliance with the established technological regime, and sometimes inter-operational acceptance of products;
systematic monitoring of the condition of equipment, machines, cutting and measuring tools, instrumentation, various means measurements, stamps, models of testing equipment and weighing equipment, new and used devices, conditions of production and transportation of products and other checks;
control of models and prototypes;
control of finished products (parts, small assembly units, subassemblies, assemblies, blocks, products).
Incoming product quality control, definition, concept
purpose, main tasks, organization of incoming control,
efficiency
Incoming product quality control should be understood as quality control of the supplier’s products received by the consumer or customer and intended for use in the manufacture, repair or operation of products.
These recommendations establish the basic provisions for organizing, conducting and processing the results of incoming inspection of raw materials, materials, semi-finished products, components, etc., coming from suppliers to consumers.
The recommendations were developed to provide methodological and practical assistance to enterprise specialists in the implementation and use of a product quality management system based on the application of international standards ISO 9000 series.
The main tasks of incoming control can be:
obtaining with high reliability an assessment of the quality of products submitted for control;
ensuring the unambiguous mutual recognition of the results of product quality assessment by the supplier and the consumer, carried out using the same methods and the same control plans;
establishing compliance of product quality with established requirements in order to timely submit claims to suppliers, as well as to promptly work with suppliers to ensure the required level of product quality;
preventing the launch into production or repair of products that do not meet established requirements, as well as permitting protocols in accordance with GOST 2.124. [GOST]
One of the elements of the relationship with the supplier is the organization of incoming control, which means quality control of the supplier’s products (raw materials, components, information) received by the consumer organization and intended for use in the manufacture, repair or operation of products, as well as the provision of services. Its main goal is to exclude the possibility of penetration into production of raw materials, materials, semi-finished products, components, tools, information with deviations from the quality requirements reflected in contractual obligations. Imperfections in this type of control can bring significant losses to both the product manufacturer and its consumer.
Incoming control is very labor-intensive and expensive, and it duplicates the output control of the manufacturing enterprise. In this regard, it is becoming increasingly important to abandon input control by strengthening output control, which entails the establishment special relationship with the supplier. The practice of such relations has existed abroad for a long time. For example, at the Japanese company Bridgestone Corporation, supplied parts and raw materials are inspected mainly to check their quantity and compliance with technical documentation. The quality of materials is not checked, as it is carried out by suppliers before sending them to the consumer. This system is based on mutual trust and cooperation.
In accordance with the terms of the supply agreement, incoming inspection can be either continuous or selective. To implement it at industrial enterprises, specialized units are created in the quality control system. Medium and large enterprises operate incoming control laboratories. The main tasks of these units are:
Carrying out incoming quality control of material and technical resources entering the organization;
preparation of documents based on control results;
control of technological tests (samples, analyses) of incoming resources in workshops, laboratories, control and testing stations;
monitoring compliance by warehouse workers with the rules of storage and release of incoming products into production;
calling representatives of suppliers to jointly draw up a report on defects detected during incoming inspection, etc. Demonstration of the effectiveness of incoming control is the reduction of cases of low-quality material and technical resources or services entering production.
Forms of incoming control include:
Periodic monitoring of the effectiveness of the supplier’s quality assurance system (the so-called “second party” audit);
The requirement for the supplier to accompany the shipment of goods with protocols of control procedures;
The requirement for the supplier to carry out 100% control and testing of the supplied material and technical resources or services;
Selective acceptance testing of a batch of goods by the supplier and consumer simultaneously;
The supplier's use of a formal quality assurance system defined by the customer (for example, based on ISO 9000 standards);
Requirements for independent third party certification of supplier products.
If we are guided by the international standard ISO 9001:2008, then in section 7 “Manufacture of products” in subsection 7.4 “Purchases”, paragraph 7.4.1 states: “The organization must ensure that purchased products comply with established procurement requirements. The scope and nature of control over the supplier and purchased products should be determined by the degree of influence of these products on subsequent production of the product or on the finished product.”
The organization shall evaluate and select suppliers based on their ability to provide products in accordance with the Organization's requirements.
Criteria for selecting, evaluating and re-evaluating suppliers must be established. Records should be kept of the results of this assessment and subsequent actions.”
In clause 7.4.2 “Purchasing Information” we read: “Purchasing information must contain a description of the products being ordered and include, where necessary:
requirements for approval of products, procedures, processes and equipment;
requirements for personnel qualifications;
requirements for the quality management system.
The organization must ensure that specified purchasing requirements are adequate before communicating them to the supplier.
And finally, paragraph 7.4.3 “Checking (verification) of purchased products is as follows: “The organization must determine and implement control measures or other activities necessary to ensure compliance of purchased products with the requirements specified in the procurement information. In cases where the Organization or its consumer intends to check (verify) purchased products at the supplier’s enterprise, the Organization must establish in the procurement information the intended measures for such verification and the method of product release.”
Incoming quality control of metal products
The main indicators of metal quality are: chemical composition; micro- and macrostructure; basic and technological properties; dimensions, geometry and surface quality of metal products. Requirements for the quality of metal and products made from it are specified in national standards, technical specifications of companies (enterprises) or separate agreements between the consumer and the supplier. The quality of the metal and reliable methods for determining its main indicators are the main ones in the technological production chain. The quality of metal products entering the enterprise is determined during incoming inspection (IC).
Incoming inspection of metal products is mandatory at companies (enterprises) that develop or manufacture industrial products, as well as repair them. This control is organized and carried out in accordance with GOST 24297-87, as well as with standards and other regulatory and technical documentation (NTD) of the enterprise.
Organization of incoming quality control of metal products:
In accordance with GOST 24297-87, incoming inspection is carried out by an incoming inspection unit - the incoming inspection bureau (IBK), which is part of the enterprise's technical quality control (QC) service.
The main tasks of incoming control are:
monitoring the availability of accompanying documentation for products;
control of compliance of the quality and completeness of products with the requirements of design and regulatory technical documentation;
accumulation of statistical data on the actual level of quality of the resulting products and development on this basis of proposals to improve the quality and, if necessary, revise the requirements of the technical documentation for products;
periodic monitoring of compliance with the rules and shelf life of suppliers’ products.
Incoming inspection must be carried out in a specially designated room (area) equipped with the necessary means of control, testing and office equipment, as well as meeting occupational safety requirements. Measuring instruments and testing equipment used during incoming inspection are selected in accordance with the requirements of the normative and technical documentation for controlled products and GOST 8.002-86. If metrological means and control methods differ from those specified in the technical documentation, then the consumer agrees specifications the means and methods of control used with the supplier.
To ensure compliance with the requirements of GOST 24297, as well as the standards of the GOST R ISO 9000 series, the enterprise is developing its own technical documentation, taking into account the profile and characteristics of the products. For example, large enterprises are developing enterprise standards (STP) “Incoming inspection of metallic materials”, “Technological instructions (TI) for incoming inspection of metallic materials”, etc.
STP establishes the procedure for organizing, conducting and recording the results of incoming inspection of metal products used at the enterprise. TI determines the scope and types of incoming inspection in accordance with the list of metals and semi-finished products subject to inspection. The scope and types of incoming inspection are established in accordance with the normative and technical documentation and technical specifications for manufactured products.
Conducting the VC is entrusted to the BVK. Input control involves: a warehouse for purchased metal products or a consumer workshop (hereinafter referred to as the warehouse) and the central factory laboratory (CPL).
Incoming inspection of metal products includes the following checks:
accompanying documentation certifying quality (certificate, passport);
labeling, containers, packaging;
geometric dimensions;
surface conditions;
special properties;
grade of material (chemical composition), mechanical properties, structure.
A typical scheme for organizing a VC (Fig. 3.1) is as follows. Metal products received at the warehouse are accepted with accompanying documentation on nomenclature, assortment and quantity and no later than 10 days are transferred for incoming control. At the incoming inspection, checks are carried out on the first four points (see above) and samples are taken to confirm the metal grade, structure, mechanical and special properties. Sampling is carried out under the control of the BVK. Selected samples are transferred to the Central Laboratory. Based on the incoming inspection data, including the conclusions of the central laboratory, a conclusion is made about the compliance of the quality of metal products with the established requirements.
Rice. 3.1. Typical scheme for organizing incoming control
If the inspection results are positive, the accompanying documentation (certificate, passport) is marked “Incoming inspection completed, complies with technical specifications”
If any indicator does not meet the established requirements, twice the number of samples from a given batch of metal is subject to control. If unsatisfactory results are received again, the warehouse, BVK and the supply department draw up a defect report.
Rejected metal is marked with red “Reject” paint and stored in a reject isolator until a decision is made on disposal or return.
Control of geometric dimensions. The TI regulates the scope of control over the size of the assortment of metal products, which is, as a rule, 5% of one batch. Dimensions are controlled using measuring instruments that provide a measurement error equal to ½ tolerance on the measured parameter.
Depending on the type of assortment (rod, strip, sheet, etc.), the dimensions specified in the certificate are subject to control, while the technical specifications stipulate how and in what places measurements are taken.
For example, the thickness of strips and tapes should be measured at a distance of at least 50 mm from the end and at least 10 mm from the edge. Tapes with a width of 20 mm or less are measured in the middle. Measurements are made with a micrometer in accordance with GOST 6507-90 or GOST 4381-87.
The thickness of sheets and plates is measured at a distance of at least 115 mm from the corners and at least 25 mm from the edges of the sheet using a caliper (GOST 166-89).
The diameters of rods and wires are measured in at least two places in two mutually perpendicular directions of the same section using a micrometer (wire) or a caliper (rod). Width and length are measured with a metal tape measure in accordance with GOST 7502-89 or a metal ruler in accordance with GOST 427-75.
Surface control. The quality of the metal surface is checked for compliance with the requirements of the normative and technical documentation for delivery visually without the use of magnifying devices (except for cases specifically stated). The recommended amount of inspection is 5% of the lot. In some cases (forgings, castings, etc.), 100% of the product is subjected to surface control.
The most common characteristic surface defects of metal products are given in table. 3.1 and in Fig. 3.2.
Table 3.1 Surface defects of metal products
Name of defect Types, origin and a brief description of defect The influence of a defect on the quality of a semi-finished product or finished product Metallurgical defects Films (Fig. 3.2, a) During pressure treatment, the walls of bubbles and shells of ingots are compressed, stretched and partially broadened. As the compression of the metal increases, the outer walls of the chambers become thin and break through. The delamination of metal formed in this way, more or less parallel to the surface and extending onto it, is called film. Removing film on semi-finished products, if their depth does not exceed the dimensional tolerances, does not affect the quality of the product. Films on the surface of the tubes lead to the rejection of products Cracks (Fig. 3.2, c, d, f, g) Cracks on the surface, as well as internal cracks, are the result of stresses arising from uneven heating, strong hardening, burns during grinding and similar reasons Cracks, that do not take the semi-finished product beyond the dimensional tolerances are classified as correctable defects. In the finished product, cracks cause rejection Bubbles (Fig. 3.2, b) If the outer wall of the finished bubble is very thin, then when the metal is heated, the gases inside the bubble expand, bulge the outer wall and form a bubble on the surface of the Shells Shells on the surface of the castings are the result of unsatisfactory molding, cutting out defects , and in products obtained by pressure treatment, as a result of opened bubbles, etc. If the shell does not take the size of the product beyond the established tolerances, semi-finished products with surface shells are considered a correctable defect. In finished products, cavities lead to rejection. Burrs and declines. A burr is a convexity along a rolled profile, resulting from the extrusion of metal from the stream into the gap between the rolls. A burr is a burr rolled into metal during finishing rolling. Burrs are also found on stamped workpieces when the halves of the cutting die are displaced. Finished rods and rods of profile metal in the presence of a burr or sunset are rejected. Ringing Ringing - herringbone-like dents and marks on the tubes, sometimes easily palpable by hand, are a consequence of the high friction force arising during the drawing process, accompanied by strong vibration. Ringing on finished tubes leads to their rejection White spots and stripes White spots and stripes are defects found mainly on aluminum products. They are a consequence of contamination of the metal with electrolyte, the presence of non-metallic inclusions and impurities of sodium and calcium. The defect sharply reduces the corrosion resistance of aluminum and aluminum products, and also damages them appearance Sodium diseaseNodium disease is the inclusion of sodium compounds in aluminum. A defect renders aluminum products defective. Ripples. Ripples are pinpoint impressions of depression on the surface of aluminum products caused by sticking to aluminum rolling rolls. Chemical defects Over-etching Over-etching is characterized by a rough surface that reveals the crystalline structure of the metal. Severe overetching in thin-walled products leads to a significant reduction in the cross-section of the walls. Overtrauma is a consequence high concentration etching substances, as well as long-term aging of products in them. dark spots or uneven surface shade. Under-etching is the result of etching with solutions of weak acids and alkalis or exhaustion of the bath, short exposure in the bath, as well as contact of products with each other during etching. Haze is the result of uneven etching caused by oil contamination during stamping, segregation heterogeneity, etc. Rough spots Rough dark and white spots on products made of light metals indicate corrosion Mechanical defects Risks and scratches Risks (longitudinal scratches) occur on internal and external surfaces as a result of poor polishing of the dies, the ingress of solid particles into them (sand, scale, metal shavings), and the ingress of the same particles into the drawing point when broaching, with non-smooth surfaces of profiles, matrices, etc. Scoring occurs as a result of pressing during high temperatures or at high pressing speeds Defects spoil the appearance, reduce the dimensional accuracy of manufactured products, and sometimes lead to defects. Fractures and tears. Fractures and tears are the result of metal rigidity, defects in the stamping tool (sharp corners) and improper installation of dies. Leads the product to defective parts. Wrinkles and folds. Most often found on drawn bodies. products and represent vertically located thickenings from metal compression. These defects arise as a result of uneven thickness of the workpiece or the gap between the dies and insufficient preheating of the workpiece. They spoil the appearance and lead to defects in the finished product. processing with abrasive tools Reduces the service life of the product and spoils the appearance of the surface. Snags on the cutting part of the tool reduce the quality of its work. Grooves. Grooves are lines visible to the naked eye and running in the direction of rough grinding on finished products (tools). Grooves spoil the appearance, reduce corrosion resistance, and in some devices and tools affect proper operation. Peeling of metal or non-metallic parts. coatings Peeling of metal and non-metallic coatings is the result of their poor adhesion to the base metal. Nicks (Fig. 3.2, e)
Rice. 3.2. Surface defects of metal products: a) films; b) bubbles on the surface; c) cracks due to strong hardening; d) crack caused by grinding burn; e) nicks; f) hardening cracks; g) grinding cracks; (f and g - revealed by magnetic powder)
If necessary control inner surface pipes, samples are cut from them, cut along the generatrix and the presence of defects is checked. In all cases, when defects are detected (including traces of corrosion), samples are taken from the locations of these defects and sent to the Central Laboratory to determine the nature of the defect and the depth of its occurrence. Based on the conclusion of the central laboratory, a decision is made on the suitability of a given batch of metal.
Control of chemical composition and mechanical properties. This control is carried out in the central laboratory on specially selected samples from each batch of metal with a conclusion drawn up in the prescribed form.
Chemical composition control. This type control is carried out in order to establish compliance of the qualitative and quantitative chemical composition of metal products with the standards stated in the certificate.
The sampling rate for monitoring the chemical composition is established in the technical specifications and is usually:
for sheets and slabs - from one control sheet, batch slab;
for tapes, strips, wire - from one control roll of the batch;
for bars and profiles that are individually stamped by the supplier - from one bar, profile, batch;
for rods and profiles marked on a tag - from 2, 3 and 5 rods, profiles for batches of less than 30 pcs., from 30 to 50 pcs. and over 50 pieces respectively.
Selected samples are sent to the central laboratory, where the chemical composition is monitored using chemical and/or spectral analysis methods.
Chemical methods of analysis, which are based on the chemical reactions of analyte substances in solutions, include mainly gravimetric, titrimetric and colorimetric analyses. These methods are described in the relevant GOSTs. It should be noted that chemical analysis is labor-intensive, not universal, and does not have high sensitivity (especially at low concentrations of the elements being determined).
Spectral analysis is a physical method for qualitative and quantification composition of a substance according to its spectra.
For express and marking analysis of the chemical composition of steels, cast irons and non-ferrous alloys, spectrographs (ISP-30, DFS-13, DFS-8) and quantometers (DFS-41, DFS-51, MFS-4, “Papuas-4”) are widely used. , the basis of which is the generally accepted scheme of emission spectral analysis. When performing an analysis, a pulsed electric discharge is excited between two electrodes, one of which is the sample being analyzed. Radiation from the atoms of the elements that make up the sample, excited in the discharge, passes through a polychromator with a concave diffraction grating and is decomposed into a spectrum. To each chemical element corresponds to its own set of spectral lines, the intensity of which depends on the concentration of the element in the sample.
At qualitative analysis the resulting spectrum is interpreted using tables and atlases of the spectra of elements. For quantitative analysis of a sample, one or more analytical lines of each analyzed element are selected from the spectrum.
The intensity (J) of a spectral line of length l is related to the concentration (c) of the element in the sample by the dependence:
(l) = a × сb,
where a and b are quantities depending on the analysis conditions.
Modern instruments for spectral analysis, as a rule, are combined with a computer, which allows fully automated analysis of spectra. In addition to the indicated devices, enterprises use steeloscopes (Fig. 3.3) of the “Spectrum” type for quick visual qualitative and comparative quantitative analysis of ferrous and non-ferrous alloys in the visible region of the spectrum. The portable version of the steeloscope (SLV) allows such analysis to be carried out in workshops, warehouses, and on large parts without destroying the surface.
Spectral analysis of metals is carried out according to GOST standards, namely:
steels - GOST 18895-81;
titanium alloys - GOST 23902-79;
aluminum alloys - GOST 7727-75;
magnesium alloys - GOST 7728-79;
copper - GOST 9717.1-82, GOST 9717.2-82, GOST 9717.2-83;
copper-zinc alloys - GOST 9716.0-79, GOST 9716.1-79, GOST 9716.2-79, GOST 9716.3-79;
tin-free bronzes - GOST 20068.0-79, GOST 20068.1-79, GOST 20068.2-79, GOST 20068.3-79.
X-ray spectral analysis. Compared to optical spectra, X-ray characteristic spectra contain fewer lines, which simplifies their interpretation. This advantage is driving the increasing use of X-ray analysis in factory laboratories.
The characteristic X-ray spectrum of a sample can be obtained either by placing it on the anode of an X-ray tube and irradiating it with an electron beam with an energy of 3-50 KeV (emission method), or by placing the sample outside the tube and irradiating it with sufficiently hard X-rays emanating from the tube (fluorescence method).
The fluorescent method is more preferable because:
has a higher sensitivity (up to 0.0005%);
more efficient and technologically advanced (there is no need to make the tube dismountable and pump it out to maintain the vacuum);
the sample is not heated.
Fluorescent X-ray spectrometers used in industry to control the chemical composition of steels and alloys (Spark-1-2M, Lab-X3000, ED 2000, MDX 1000) are equipped with a computer, which allows you to automate the process of processing spectra and increase efficiency (Fig. 3.4).
The results of control of the chemical composition of the metal are documented in the accompanying documentation and registered in the incoming control passport.
Rice. 3.3. Optical design steeloscope: 1 - light source (electric arc between the electrodes, which serve as the samples under study); 2 - capacitor; 3 - slot; 4 - rotary prism; 5 - lens; 6 and 7 - prisms that decompose light into a spectrum; 8 - eyepiece
Rice. 3.4. Functional diagram of a fluorescent X-ray spectrometer: RT - X-ray tube; A - analyzer; D - detector
During the incoming inspection of imported materials, the grade of the material is determined in accordance with the certificate chemical composition.
Control of mechanical properties. This type of control is carried out at the Central Plant in accordance with the requirements of STP and TI. The content and scope of control of the mechanical properties of metal products supplied to the enterprise are determined by the grade of metal, delivery condition and purpose in accordance with the normative and technical documentation.
As a rule, mechanical properties are controlled by testing: uniaxial tension, hardness, and impact strength (see Chapter 2). The shape and dimensions of test samples must comply with the requirements of GOST 1497-84 and GOST 9454-78.
For tensile testing of round, square and hexagonal metal, 2 samples, 60 mm long from either end of the rolled product, are taken from each batch.
For tensile testing of wire supplied in coils for the manufacture of springs, a sample 600 mm long is taken from one coil of each batch, and for wire with a diameter 0.9 mm one sample 1500 mm long at a distance of at least 1 m from the end of the coil.
For tensile testing of rolled sheets, two samples 250 mm long and 50 mm wide are taken from one sheet along the rolling direction, and from sheets of aluminum and magnesium alloys - across the rolling direction. For tapes and strips, a sample 400 mm long is taken from one roll of each batch at a distance of at least 1 m from the end of the roll.
To test the impact strength of sheets, strips with a thickness of at least 11 mm, pipes with a wall thickness of at least 14 mm, rods with a diameter of at least 16 mm, 2 samples of size 11 are taken from either end next to the tensile test sample × 11× 60 mm for making samples size 10 × 10× 55 mm. From rolled products with a thickness of up to 10 mm, 2 samples are taken to make samples of size 5 × 10× 55 mm. To test impact strength at sub-zero temperatures, 3 samples are taken.
If results are obtained that do not comply with the certificate, the test is repeated on twice the number of samples. If repeated tests yield negative results on at least one sample, then the entire batch of metal is rejected. The results of the mechanical properties of the metal are reflected in the incoming inspection passport with test tables attached.
Conclusion
In the global market into which the Russian economy is integrating, enterprises need management that provides advantages over competitors in terms of quality criteria. Gradually, the understanding comes that to produce products of the required quality, it is no longer enough to have a technical control department.
All larger number In order to increase their competitiveness, enterprises are aware of the need to create a quality management system and certify it for compliance with the requirements of international standards.
Having studied the topic “Quality Management”, we found out that the direct management of the quality management system is carried out by an authorized person, and that his responsibilities include:
ensuring the development, implementation and maintenance of a quality management system;
control over internal audits of the quality management system, analysis of its effectiveness;
submitting reports to the director on the functioning of the quality management system, analyzing its effectiveness.
We also found out that operational activities related to the functioning of the quality management system are carried out by a specially created quality service, whose tasks include:
coordination of work and direct participation in the development, implementation and operation of the quality management system;
creation of a database on the quality management system;
organizing accounting and monitoring the implementation of measures and documents of the quality management system, conducting internal audits;
improvement of the quality management system.
Under the new requirements, the organization must establish and specify in detail product/service measurement requirements, including acceptance criteria. Measurement must be planned to confirm their compliance with the detailed requirements. The organization should plan to use statistical methods to analyze data. In problem analysis, causes must be identified before corrective or preventive actions can be planned. Information and data from all parts of the organization must be integrated and analyzed to evaluate general state performing work in the organization. Based on objective information, methods and means for continuous process improvement are determined.
Effective functioning of the quality system involves the creation and operation of an information retrieval system, corrective actions and results obtained in the field of quality.
Having a certified quality system at an enterprise is not an end in itself. Firstly, a number of industries have their own specific certification systems. Secondly, ISO 9000 certification is a necessary but not sufficient element of competitiveness. And thirdly, recognized leaders of the market economy create their own, more developed and advanced quality management systems. But there is no doubt that the absence of an appropriate quality system deprives an enterprise of the prospect of surviving in conditions of fierce competition.
List of used literature
1. Rebrin Yu.I. Quality control: Tutorial. Taganrog: TRTU Publishing House, 2004. 174 p.
Great Soviet Library, TSB; #"justify">. Gludkin O.P. Methods and devices for testing RES and EVS. - M.: Higher. School., 2001 - 335 p.
Unofficial GOST website; #"justify">. Build Consultant; #"justify">. A.I. Orlov Mathematics of chance: Probability and statistics - basic facts: Textbook. M.: MZ-Press, 2004, - 110 p.
V.G. Shipsha. Lecture: Incoming quality control of metal products.
Types of quality control
Solid
Selective
Incoming control
Interoperational control
More accurate classification
Quality Management System Certification
Certification- a procedure confirming by a third party the compliance of a product, process or service with specified requirements and issued in the form of a written guarantee.
The quality management system in ISO 9000 standards is understood as part of the enterprise management system, based on documented procedures for managing and executing business processes.
ISO 9000 is a series of international standards for creating a quality management system.
Certification of quality management systems is a highly effective market tool, since a certificate issued by a reputable organization is recognized as tangible evidence of the quality that the consumer (customer) has the right to expect.
Staging modern management quality management assumes that the enterprise must undergo a systemic restructuring of its activities, affecting tasks that, to one degree or another, rely on the principles of quality management laid down in the ISO 9000 series standards (strategy, structure, processes, personnel).
The certification procedure aims to give the manufacturer of the relevant products a license to use the mark of conformity.
In Russia, in accordance with the Law on Certification of Products and Services, a state product certification system has been created, which operates under the leadership of Gosstandart of Russia as the national certification body. The national standard describing the QMS certification procedure is GOST R 40.003. This system complies with ISO rules.
The basis for certification in terms of human safety and environmental protection are domestic or foreign standards.
Having a certified system allows an enterprise to:
1. reduce unproductive costs (production losses);
2. improve the level of quality of products or services;
3. be more competitive;
4. improve organizational structure management and increase its efficiency;
5. increase product sales;
6. sell manufactured products on the international market;
7. the possibility of obtaining preferential loans;
8. receive a state, municipal, or city order for the production of works and services;
9. form public opinion about the stable position of the enterprise in the market.
Question 28. Fixed assets: concept, composition, structure. Basic production and non-production assets. Depreciation and reproduction of fixed production assets. Depreciation and methods of its calculation.
Fixed assets – These are tangible assets (implements of labor) that are repeatedly involved in the production process, do not change their natural material form and transfer their value to the finished product in parts as they wear out.
Classification of fixed assets.
1. By purpose and scope of application:
Basic production assets;
Basic non-production assets.
2. By degree of use:
Fixed assets in operation;
Fixed assets in reserve;
Those in the stage of completion, reconstruction, partial liquidation;
Preserved.
3. Depending on existing rights to property:
Objects owned by an enterprise;
Objects under operational management or economic management;
Objects received for rent.
4. According to natural composition:
Facilities;
Transfer devices;
Cars and equipment;
Vehicles;
Tools, production and household equipment
Based on the degree of participation in the production process, fixed assets are divided into active and passive. The active part (machines, equipment) directly affects the production, quantity and quality of products (services). Passive elements (buildings, structures, transport) create the necessary conditions for the production process.
Types of quality control
Thus, a distinction is made between sample, continuous and statistical types. Solid All products undergo inspection. During continuous control in production, records are kept of all defects that arise during the manufacturing process of the product.
Selective- control of a part of the product, the inspection results of which apply to the entire batch. This type is precautionary, hence it is carried out throughout the entire production process in order to prevent the occurrence of defects.
The process of product quality control at enterprises is carried out by the technical control department (QC) or the quality control department.
Incoming control- checking the quality of raw materials and auxiliary materials entering production. Constant analysis of supplied raw materials and supplies allows us to influence the production of supplier enterprises, achieving improved quality.
Interoperational control covers the entire technological process. This type is sometimes called technological, or current. The purpose of interoperational control is to check compliance with technological regimes, rules of storage and packaging of products between operations.
Output (acceptance) control- quality control of finished products. The purpose of final inspection is to establish compliance of the quality of finished products with the requirements of standards or technical specifications, and to identify possible defects. If all conditions are met, then delivery of the product is permitted. The quality control department also checks the quality of packaging and the correct labeling of finished products.
More accurate classification
Factors affecting product quality
At each enterprise, the quality of products is influenced by various factors, both internal and external.
Internal ones include those that are related to the enterprise’s ability to produce products of appropriate quality, i.e. depend on the activities of the enterprise itself. They are numerous, they are classified into the following groups: technical, organizational, economic, socio-psychological.
Technical factors most significantly influence the quality of products, therefore the introduction of new technology, the use of new materials, and higher quality raw materials are the material basis for the production of competitive products.
Organizational factors are associated with improving the organization of production and labor, increasing production discipline and responsibility for product quality, ensuring production culture and an appropriate level of personnel qualifications.
Economic factors are determined by the costs of production and sales of products, pricing policies and the system of economic incentives for personnel for the production of high-quality products.
Socially - economic forces significantly influence the creation of healthy working conditions, loyalty and pride in the brand of their enterprise, moral stimulation of workers - all these are important components for the production of competitive products.
External factors in conditions of market relations contribute to the formation of product quality. The external or environment is an integral condition for the existence of any enterprise and is an uncontrollable factor in relation to it. All impact external environment can be divided into the following individual factors: economic, political, market, technological, competitive, international and social.
Analyzing the external environment enables an organization to forecast its capabilities, to make a contingency plan, to develop an early warning system against possible threats and to develop strategies that could turn external threats into any profitable opportunities. Analysis of the external environment is necessary in the process strategic planning.
Among the environmental factors considered, competitive factors occupy a special place. No organization can afford to ignore factual or possible reactions their competitors.
In the conditions of market relations, the goals of the enterprise change, which combine the following issues: ensuring survival, maximizing load, maximizing current profits, gaining leadership in the market segment, gaining leadership in terms of product quality, achieving a specific sales volume, growing sales, winning the favor of the client.
The fourth stage consists of analyzing and evaluating information. This allows you to determine the presence and extent of deviations from the specified parameters and the need for corrective actions.
The third stage of the control process is to obtain information about the state and results of the functioning of its object, allowing one to make informed decisions about how to proceed.
At the second stage, a model of the organization is created, which reflects the flows of resources, information, where costs arise, and the formation of intermediate and final results that are most suitable for observation.
By subjects that carry out the control process (administration, functional services, special units, employees themselves).
By type (financial, production, quality control, etc.).
3.By objects, which are:
State of production, technical, personnel potential, volume financial resources, inventories;
-efficiency of production activities;
- intermediate and final results, etc.
5.By intensity(normal or enhanced).
6. At the place of implementation(volatile, stationary).
7.By goals(filtering, correcting).
8.By methods:
-actual
-documentary
-evaluative.
9.By stages of implementation: preliminary, current, final.
Preliminary control is carried out before the start of work. Its main means is the implementation of certain rules, procedures, and lines of conduct, the observance of which allows one to develop in a given direction.
Current (operational) control is carried out during the work and makes it possible to exclude any deviations from the planned plans and instructions, which does not allow these deviations to develop.
To implement control, feedback is necessary, i.e. data on the results obtained.
Final (final) control is carried out after completion of work.
He does two important functions:
1.Provides information for planning(if similar work is carried out in the future).
2.Promotes motivation(i.e. ensures fair compensation).
Control is an activity to regulate relations in an organization, aimed at creating favorable conditions for the preparation and implementation of management decisions.
Each of the identified types of control is aimed at a specific object, which serves as the main basis for their identification.
To carry out the control procedure, it is necessary to sequentially overcome its four stages(Fig. 5):
Rice. 5. Stages of the control process.
At the first stage, the parameters of the functioning and development of the organization that need to be controlled and the sources of information about them are determined. These parameters take the form of various standards and regulations, reflecting the objectives laid down in the plans.
The control process is a diachronic process and covers time as initial stage management, and its final part. And if the diagnostic and orienting control functions fall primarily on the input blocks of the information-cybernetic control model, then the stimulating and corrective functions fall on the output blocks. Coordination of control over time is the most important generic characteristic of control activity, which makes it relevant to divide it into preliminary, current and final stages, which fall into two key forms within the information-cybernetic model: input and output control.
Incoming control is designed to carry out the functions of monitoring and regulating information flows entering the control apparatus. The content of these flows should include information about the material, financial and energy sources of the organization’s activities, and their staffing. At the entrance, supervisory authorities must ensure that all tasks arising from the strategic planning scheme are correctly distributed, so that each member of the organization clearly understands what he must do and what his responsibility is for violations committed. Incoming control is also necessary to assess the state of the production system and its vulnerabilities - unique channels for possible destruction of the system.
The object of input control is the flows entering the production system of the enterprise, which serve as the initial condition for the activity of this enterprise. The list of these flows includes:
-material (equipment, raw materials, resources);
-technological (patents, know-how, etc.);
- personnel;
- informational;
-Financial, etc.
The most important condition, preceding the control procedure, is bringing the current goals of the organization to the attention of performers. To do this, the controlling entity must know what the output should be and how best to implement it. Control shouldn't be scary and therefore the purpose of control will not be prohibition or threats, but maintenance optimal mode in the work of subordinates. Control should be more preventive than ascertaining.
There are two types of input control: direct and indirect.
Direct control- this is the activity of managing input flows attributed to the staff manager in accordance with his job descriptions . Direct control divided into two subspecies: strict executive control, the object of which is the performer’s activity itself, and soft functional control which involves monitoring mainly the results of activities, and not the form of activity of the performer.
Direct control may include factors formed at the intersection of two conditional axes: the goal and the means to achieve it. The goal axis usually consists of such objects of input control as hiring workers, determining the scope of work, the quality and timing of tasks performed, etc.. On the means axis, you can put aside such indicators as the personal qualities of those hired or receiving tasks, the conditions of work, the nature of personnel training etc. Calculation of optimal combinations between the set control goals and the means available for this purpose will allow the manager to evenly distribute among the controllers the scope of their direct responsibility for the implementation of the goals. The scoring of the calculation will help to identify priorities in assessing a particular level in order to choose the optimal tactics in achieving the control goal.
Indirect control– activities for managing input flows, based on the indirect powers of the manager. Indirect control is divided into two types : control through related indicators and self-control.
Control through related indicators is based on the identification of such control standards (standards), the value of which is objectively related to each other . Thus, while controlling the level of costs in an enterprise, an official cannot help but control the level of profit. We have to admit that the list of standards defining control zones at the enterprise causes these zones to overlap each other, which can lead to a loss of clarity in the distribution of areas of control.
Self-control expresses the highest degree of trust between the manager and the subordinate, especially in cases where direct methods of control are impossible, or where there is long distance between executive and regulatory bodies . The well-worn phrase “Conscience is the best controller” is a good illustration of this type of control. Currently, the share of self-control is rapidly increasing. This is due to the increasing complexity of the production and marketing system.
Incoming quality control is intended for basic and auxiliary materials: paper, paint, dampening solution, offset cloth.
The main stages of paper quality control are determining whether the printing and technical properties of paper comply with the standards. The first stage is a visual inspection. When examining the foot, you need to pay attention to the integrity of the packaging, and when opening it, to the presence of folds and wrinkles, waviness and dirt. Next stageЇ measurement of paper moisture content. The moisture content of paper is measured using moisture meters, and it should be within 5-7%. The last stage is the definition of paper whiteness. Whiteness control is carried out using a densitometer. For light paper(with a mass of 60 g/m2) the opacity indicator is important, because Such paper requires a more careful approach to the choice of paint in order to avoid such a common defect as the image showing through from the back. The method for determining the transparency of paper is examining the paper against light or using densitometers.
Along with the properties of paper, the quality of printed products is also influenced by the properties of inks. The main indicators are viscosity, thixotropy and degree of grinding. To assess the viscosity of offset inks, rod viscometers are used; the measured values must correspond to those specified by the manufacturer. To assess thixotropy, visual control is used (mix the paint and see how long it takes for the paint and binder particles to form a dense structure). To assess the degree of grinding of offset inks, the “Wedge” device is used.
To adjust the properties of paints, various additives are used to adjust the drying speed of paints and the performance properties of their films on the print. Various oils are also used to prevent drying.
To assess the quality of the moisturizing solution, indicators such as acidity, electrical conductivity and hardness of the water used are used. Acidity ( pH) moisturizing solution is one of the most important indicators. Optimal values pH fluctuates between 4.8-5.5. Important to remember, pH the solution must match pH paper, otherwise the printing may result in a defect ( yellow spots on paper). The electrical conductivity of the moisturizing solution Ї is an indicator characterizing the content of salts and various additives in the moisturizing solution. Electrical conductivity tap water usually ranges from 300 to 500 µS. The operating electrical conductivity of the moisturizing solution should be in the range from 800 to 1500 µS. Optimal value water hardness when preparing a moisturizing solution is 250.25-600.6 ppm Even small deviations from these values can cause printing problems.
Control of offset blankets is carried out by measuring Shore hardness. If necessary, the rigidity is adjusted by placing calibrated cardboard under the offset blanket.
Output control
The quality of production prints is controlled using control elements (alignment crosses) and scales located on the sheet.
The quality of the alignment is assessed visually using a magnifying glass. Control of the supply and uniformity of paint and moisture supply is carried out using dies, which can be visual and using a densitometer. Control of the paint-moisturizing solution balance is carried out visually using dies and raster elements of each color.
Control of the deformation of raster elements (dot gain) is performed visually for each paint by comparing a 50% dot raster field with a line field.
Control of color balance “in gray” is carried out visually in 3 fields: light, penumbra and shadow. With high-quality printing, the control element has a neutral gray color.
Sliding and crushing control is carried out visually. Printing slip control elements consist of a set of straight or concentric lines. Since any sliding Ї is the creation of a second identical image, the superposition of two periodic structures with linear or angular displacement will lead to the appearance of moire.
Quality control of the reproduction of small elements in highlights and shadows is carried out using fields having a point with a relative area of 1, 3, 5 and 95, 97, 99%. I use a magnifying glass to control.
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