Stages Of Technological Process Research Articles

Sewing technologies as interdisciplinary innovations in architecture

The article explores interdisciplinary approaches in architecture related to the use of sewing and textile production technologies. The main technological processes of manufacturing sewing and textile products, as well as adapted sewing production technologies in research prototypes and real buildings and structures made of wood are considered. The research is conducted on the basis of an interdisciplinary approach, involving knowledge from the history of architecture, applied arts and design, information technology and engineering. Special attention is paid to the experimental work of the University of Stuttgart, where automated production processes are used to create experimental architectural prototypes from multilayer wooden veneer. As a result of the study, three main stages of technological processes for the manufacture of garments were identified, which can be adapted for the manufacture of architectural objects. It is demonstrated that an interdisciplinary approach using sewing and textile technologies leads to a revision of techniques and methods in the fields of construction engineering, automation, digital manufacturing and materials science. Experimental prototypes and structures not only have efficient and resource-saving qualities, but also have a high level of architectural and artistic solutions. The use of sewing technologies opens up new opportunities for creating innovative and unique forms and designs in architecture.

WASTEWATER RECLAIMING AND RECYCLING: ESSENCE AND DIRECTIONS FOR IMPLEMENTATION

Topicality. The topicality of the research results from the fact that according to the data of the United Nations (UN), 36% of the world's population lives in water-scarce regions, in particular Ukraine is ranked 125th among 179 countries on the indicator of total internal renewable water resources per capita, which states that Ukraine is poorly supplied with freshwater. In recent years, special attention of international communities have been paid to the wastewater reclaiming and recycling as a possible alternative to traditional water supply and solution of water scarcity problem. In the UN World Water Development Report 2017, it is noted the need to use wastewater as a resource since fresh water has become increasingly scarce. Aim and tasks. The purpose of the article is to determine the essence, features and directions for wastewater reclaiming and recycling implementation to ensure sustainable water resources management in Ukraine. Research results. The results indicate that climate change, rapid urbanization and population growth affect the state of water resources and the population's access to fresh water. In order to find ways to overcome the natural water shortage, it was proposed to use alternative sources of water supply, in particular, wastewater reclaiming and recycling. Based on the analysis of national and foreign regulatory legislation, the modern semantic content of the concepts of "wastewater reclaiming" and "wastewater recycling" has been clarified, and a scheme for introducing the wastewater reclaiming and recycling into the water cycle has been developed. Statistical data on providing the population of Ukraine with centralized water supply and drainage systems and the amount of volumes of untreated wastewater discharged into the environment have been analyzed. The analysis was carried out and the main areas of recycling of wastewater reclaiming components were determined. Conclusion. Considering the importance of ensuring sustainable water resources management, the authors of the article determined the place and role in the introduction of wastewater reclaiming and recycling. The study demonstrated that 97% of Ukraine's wastewater is not recycled, and more than a quarter of the discharged wastewater in the Odessa region is discharged without proper treatment, which has extremely detrimental consequences for the environment and human health. The stages of technological processes of centralized water supply and sanitation services are considered and the introduction of wastewater reclaiming into the water use cycle, in particular in the energy, manufacturing, agricultural sectors and for municipal and domestic needs, is proposed. It is argued that the introduction of wastewater reclaiming and recycling contributes to the development of a circular economy and provides certain socio-economic-environmental benefits, including reducing environmental impact, avoiding overexploitation of water resources and increasing water availability in arid regions of Ukraine.

Intellectual and natural resources: new opportunities for development

The article analyzes the role of intellectual resources in the development of extractive industries through research on promising technological solutions for the main stages of technological processes. The relevance of the study lies in the possibility and necessity of using patent analytics as a tool for forming growth points for high-tech sectors of the economy in resource-type regions. The authors suggest that the oriented adaptation of patent analytics tools will solve a large-scale scientific problem - to identify patterns and dependencies of changes in the mining and geological conditions of subsoil use and, accordingly, the main parameters of mining machines, over time and develop a methodology for predicting and justifying the promising parameters of various mining machines as one functional purpose, and multifunctional, ensuring their efficient operation for a given period of time.

Development of the fundamental diagram of the formation and transformation of the products properties during their manufacturing

In object-oriented technologies of mechanical engineering production the step-by-step execution of interconnected design stages of technological process of product manufacture is used. A systematic approach to research and qualitative modelling of real physical processes, taking into account the operational characteristics of products and machines at all levels of research is ignored. As a rule, the object-oriented technological processes do not track the change of the products properties during their manufacture from the position of technological inheritability for all stages and substages of the Life Cycle Support of Product. Therefore, the development of scientific and applied principles of technological inheritability of quality parameters to provide the operational characteristics of products in the design of function-oriented technologies is a priority item of modern mechanical engineering. The structure of functional-oriented technology is closely related to the stages and substages of Life Cycle Support of Product. From the standpoint of continuous damage mechanics, Life Cycle Support of Product is considered to be a single process of exhaustion of the material plasticity margin under the influence of certain load modes in accordance with the technological inheritance of the product properties. The basic chart of the formation and transformation of the products properties from the point of view of mechanics of technological inheritability is developed. This chart, in contrast to previous research in this area, takes into account the significant impact of the stage of blanks manufacture in the technological process structure on the formation of technological parameters and operational characteristics of products.

Optimization of Production of Blast Furnace Ferromanganese in Conditions of Non-Integrated Iron Works

Production of high carbon blast furnace ferromanganese (HC FeMn) in conditions of Russian non-integrated iron works stipulates use of various combinations of permanently changed sorts of manganese ores with different mineralogy, manganese content and granulometric composition. Operation complexity is caused by challenge to satisfy with customers’ stringent requirements specific to percentage of manganese, silicon and maximum permissible content of tramp elements in produced alloy as well as by necessity to recycle fine fraction formed at the stage of crushing of solidified large-sized ferromanganese. Fluxless technological regime is defined as a most efficient mode to achieve high technical and economic indices. Special attention is given to methods of increase of manganese recovery in every stage of technological process. The largest losses of manganese are related to losses with slag and top gas, and developed techniques to minimize these losses are described with taking ecological aspects into consideration.

Особенности локализации деформации при термосиловой обработке

The paper considers the issues of ensuring the uniformity of strain of axisymmetric long-dimensional samples during thermal force processing (TFP), which is the simultaneous application of force and temperature effects for comprehensive improvement of geometric characteristics and physical and mechanical parameters of the workpiece material. This technology is used at various stages of technological processes of parts manufacturing, but its main task is to ensure the axis straightness and the specified distribution of residual technological stresses at the procuring stage. The disadvantage of TFP is that the axial deformation proceeds nonuniformly along the workpiece axis. The core process parameter is the deformation, the control of which is a key factor ensuring the TFP efficiency. The authors studied the plastic strain distribution over the sections of long-length workpieces with different deformation degrees. The study involved the assessment of strain uniformity over the workpiece sections, taking into account the stage of the stress-strain relation at the end of the loading cycle. Based on the concepts of plastic deformation as an auto-wave process, the authors selected the range of technological modes corresponding to the most uniform strain distribution along the workpiece axis with complete processing of the entire workpiece volume. This range corresponds to the stage of parabolic hardening of the plastic flow curve with the formation of the maximum number of stationary zones of localized plasticity. Rheological modeling allows identifying the control points that specify the boundaries of the plastic flow curve stages at various loading parameters, including temperature. To improve the reliability of determining the actual deformation under production conditions, the authors proposed modernizing the TFP process monitoring method by fixing the deformation on a limited workpiece section using the optical technique. The statistical analysis of the strain distribution over the sections for the samples confirms the correctness of this approach. The application of the proposed control method will ensure the most uniform distribution of plastic deformation due to the reliable enter of the workpiece deformation to the range of strain values corresponding to the stage of parabolic hardening of the plastic flow curve.

Use of clarifying agents in technological process of kvass production

In our country, the production of soft beverages is a popular direction of food industry. Fermented kvass, fruit and berry drink, lemonade, carbonated drinking and mineral water, and others are referred to non-alcoholic drinks. Currently, consumers increasingly prefer natural drinks consisting of traditional ingredients. One of the traditional drinks since ancient times revered in Russia, is bread kvas of natural fermentation. In the production of fermented drinks, modern technologies, the newest equipment, automated manufacturing processes are used, which allow intensifying technological plots for fermented kvass production using new methods. This allows optimizing stages of technological process and the entire production. The use of new methods for optimizing production processes allows reducing costs of production by reducing the time component of the technological process of kvass production.

The Use of Composite Polymeric Materials to Increase the Effectiveness of Ship Ventilation Systems

The article presented the use of composite polymeric materials to increase the effectiveness of ship ventilation systems in the process of its machining. As the result of the research, the author considered that, it is important to evaluate and anticipate all possible factors (technical, technological, ergonomic, environmental) associated with the negative impact of excessive production waste generation (chips and dust) in the workplace at the design stages of technological processes for machining parts made of composite materials. The research results determined the possibility of using composite polymer materials for manufacturing the structures of ship ventilation systems, as well as other ship systems.

Increase of Durability of Austenitic Steel by Overlap of Carburization and Diffusion Saturation from Liquid Metal Medium Solutions Technologies

This paper investigated the overlap of carburization and diffusion saturation from liquid metal medium solutions technologies. The carburization of austhenic steel able to increase of its wear resistance and microhardness to 700HV. But this kind of treatment provided to reduction of corrosion resistance. This effect conditioned by formation of chromium carbides, herewith austenite of steel impoverished of chromium. This paper proposes the new technology lets increase the durability of asthenic steels, using carburization and diffusion saturation in eutectic Pb-Bi-Li medium with adding of nickel and chromium. The most effective technology consisted of previous carburization, diffusion saturation and final carburization. First carburization provided to increase of surface layers microhardness to 2800 MPa, diffusion saturation to 7500 MPa, the final carburization to 19500 MPa. The properties of coating depended of combination of technological impact and technological modes of every stage of technological process: temperature and duration. The temperature influenced to microhardness of coating: when the temperature increased microhardness decreased. The duration of diffusion saturation influenced to thickness of diffusion layer: when the duration increased the thickness increased too

Thermodynamic analysis of liquid steel refining by complex alloy containing La - Ce -Al

Alloys containing rare-earth metals (REM) are increasingly used in production of steels and alloys. After modification and microalloying of steel with REM, structure of primary metal is refined, its mechanical characteristics are upgraded, concentration of oxygen dissolved in liquid iron is decreased significantly, and originated nonmetallic inclusions do not exceed several microns in size and are of predominantly globular shape. Due to relatively high cost of REM, it is proposed to calculate their consumption at each stage of technological process to determine optimal amount required for deoxidation or modification. In this work, thermodynamic modeling of phase equilibria in liquid metal of Fe - La - Ce -Al - O system has been performed. The authors provide a base of thermodynamic data of the system under study: temperature dependences of the equilibrium constants of reactions between the components, values of the first-order interaction parameters (according to Wagner) for elements in liquid iron, values of energy parameters of the theory of subregular (for oxide melt) and regular (for solid solution) ionic solutions. Based on coordinates of calculated isothermal (1600 °С) isostructural (0.01 wt. % aluminum) cross section of solubility surface of components in metal (SSCM) of the Fe - La - Ce -Al - O system, lanthanum and cerium flow diagrams were constructed for various initial oxygen concentrations (metal is pre-deoxidized with aluminum). It has been shown that costs of expensive REM used in microalloying and metal modification strongly depend on composition of the initial metal.

A method of determination of average plane of taps of pipes by triangulation method using an anthropomorphic robot

Nowadays there are various manufacture methods of pipe taps. One of the most laborious operations during manufacture is a marking of pipe taps for subsequent machining. Work layout operations are performed using special tool ware and outfit. These operations are performed manually and it leads to the decrease in accuracy and to the increase of laboriousness. The authors suggest the method of determination of the latent base of pipe tap (average plane) using an anthropomorphic robot. The results of research would help to make the virtual calculation of tool position of the anthropomorphic robot for marking and to generate the robot trajectory. Ultimately, such research would also decrease laboriousness and increase accuracy of marking operation. Materials and methods. The authors supposed to use latent base, namely the average plane of the pipe tap as a measuring base. The robot is calibrated from the base plane placement and chooses the shortest circular arc by comparative approach. Therefore, such shortest arc would form the average plane. The authors carry out the determination of the curve line length by the triangulation method using the interferometer. Results. The result of the research is the technology development for determination of latent base in the average plane form. Discussion and conclusion. The proposed method of latent bases determination of pipe tap would allow making the automated system of marking of pipe taps. Moreover, such method would help to reduce time of performing operations as well as to decrease the manufacture laboriousness on the following stage of technological process.

Stages of technological process of high anisotropy formation of magnetic properties under «dry» pressing of powder products

The article proposes the description of technological production process of anisotropic products from powders of high materials which provides powders preparation and products made of them. It has been shown that the main drawback of «wet» pressing technology is low accuracy at dosing wet charge. To eliminate warping and cracking of briquettes obtained by «wet» pressing during the sintering, they are subjected to air drying at room temperature within 48-72 hours. However, the percentage of product failure due to mechanical and magnetic characteristics remains high. Practically all the drawbacks of «wet» pressing can be eliminated by reverse to dry powder pressing, which allows to obtain low mass magnets without additional final finishing machining, to avoid warping and cracking of the product, and to reduce sintering time. Nevertheless, under the dry powder pressing the magnetic characteristics of products are significantly lower than under the wet pressing. When working with disperse materials, a promising direction is to converse them into fluidized state. To obtain the fluidized state of powder materials, vibrational technologies are used, involving the transfer of a wide range of energy to the powder material, i.e. mechanical, acoustic, electric and magnetic energy.

Designing of organizational and technological solutions for construction in constrained urban environments

The article substantiates the need to improve the quality of design work on the construction site in the context of the existing urban development taking into account specific criteria and gradations. The features and problems of the main periods of construction are investigated. To improve the quality of the design documentation, in particular, of the construction work program in constrained urban conditions, the authors conducted the research of the influence of a complex of constraint factors affecting construction preparation activities. Recommendations of construction site organization in the current conditions are given. The results are presented and further research stages of technological processes in constrained urban conditions are outlined. We show the expediency of a systematic approach to improving the quality of construction’s process. We are taking into account the assessment of environment state and the need to reduce the negative impact of construction and assembly works on nearby already built-up areas. The need to take into account the above factors for developing a project of works execution is justified.

ГИДРОМЕТАЛЛУРГИЧЕСКАЯ ТЕХНОЛОГИЯ ПЕРЕРАБОТКИ ЦИНКСОДЕРЖАЩИХ ШЛАМОВ СТОЧНЫХ ВОД ПРОИЗВОДСТВА ХИМВОЛОКНА

Large areas of storage sludge pose a risk of contamination of soil, groundwater and crops, respectively, pose a significant risk to humans and other living organisms, because heavy metals accumulated in plants are included in food chains and enter the gastrointestinal tract with foodstuffs. Over time, sludge stores overflow, causing the need to build new structures. The introduction of sludge recycling technologies will free up the area occupied by sludge storage facilities, eliminate the cost of building new sludge and profit from the extraction of valuable components. Such, for example, is zinc, whose content in natural raw materials is 1-3 %, and in the waste of the production of viscose fiber 6.5-40 % (depending on the range of products, and reagents used for wastewater treatment). Zinccontaining sludge at medium-sized enterprises is 1,000,000 tons, allowing it to process that amount of sludge with a capacity of 10 tons per hour for 10 to 15 years. In the early works in the laboratory, physical and chemical laws of zinc-containing sludge processing were established and technological process of sludge utilization into zinc sulfate was developed, the composition and physical and chemical properties of zinc-containing sludge were investi-gated, the conditions of processing and rational ways of utilization were determined, the influence of temperature on contact duration, reagent concentration, mixing intensity was investigated for the zinc hydroxide extraction process, zinc content purification technology was proposed, impurity solution, comparative feasibility studies and cost effectiveness of sludge processing were performed. The paper presents a study of hydrometallurgical method of processing zinc-containing sewage sludge by leaching. The removal of zinc from the sludge is carried out on a semi-industrial installation. To study the particle size distribution of the source ore, wet sieving method is chosen. Phase chemical analysis on the forms of zinc is carried out. Also, X-ray and thermogravimetric analyzes are applied to study the real composition of the sample. On the basis of a series of experiments on a semi-industrial installation, the main stages of technological process are identified and investigated. According to the results of the research, the technological process of obtaining zinc sulfate from zinccontaining sludge production of viscose fiber is developed. It is proposed to divide the process into separate stages, in order to develop a flexible technological scheme, which allows the processing of different raw materials. For complete and effective extraction of zinc, the insoluble residue after the leaching step is proposed to be treated with a nitric acid solution, which allows to obtain an additional product – calcium nitrate enriched with micro-impurities. According to preliminary ecological and economic calculations, the profit from the sludge processing for one year will be about EUR 1.684 million. Through the implementation of the proposed scheme for the use of secondary products, a significant social effect is achieved by improving the environmental situation by reducing the amount of waste in the sludge collectors, creating jobs.

ИСПОЛЬЗОВАНИЕ ЦИКЛОНА И ЭФФЕКТА "МИКРОВЗРЫВОВ" КАПЕЛЬ ВОДОТОПЛИВНОЙ ЭМУЛЬСИИ ПРИ КОМПЛЕКСНОЙ ОЧИСТКЕ ВЫХЛОПНЫХ ГАЗОВ ДВИГАТЕЛЯ ВНУТРЕННЕГО СГОРАНИЯ

Obtaining additional energy due to the deep utilization of the internal combustion engine (ICE) heat losses al-lows saving fuel used for the operation of the ship's power plant. This accordingly leads to a reduction of the emissions of harmful substances into the atmosphere, contributes to meet the more stringent standards of the International Maritime Organization (IMO) governing the limits of these emissions. The study aims to develop the system of complex exhaust gas cleaning for an internal combustion engine (ICE). For solving the tasks in the technology of proposed method there were 6 stages of technological process envisaged. Based on experimental and theoretical studies, a setup for complex exhaust gas cleaning using a cyclone and the effect of "microexplosions" of a water-fuel emulsion (WFE) droplet was developed. It has been established that as a result of activated WFE combustion we obtain at the engine outlet exhaust gases of a corresponding composition with a reduced amount of toxic ingredients down to 35 % and below and most importantly – an equimolar ratio of NO2 /NO to NOx. Experimental studies have shown that in the condensate acid under these conditions, an average concentration of about 57 % is established, which ensures a sharp increase in the absorption of SO2 and NOx. The presence of an equimolar (or almost this) NO2 /NO ratio in gases ensures the passivation of the condensation surface in exhaust gas boiler (EGB) from carbon steel. This ensures a sharp decrease in the low-temperature corrosion intensity, an increase in the operating reliability of condensation surfaces and the possibility of a sharp increase in the engine exhaust gas utilization depth to 80...90 °C instead of 160 °C. For the final gas cleaning, it was proposed to install a venturi scrubber and a cyclone-absorber on the gas path of ICE. Based on experimental studies, it has been established that the installation of a condensation heating surface in the EGB reduces the NOx content in gases by 55 %, SO2 - by 50 %, and the content of solid particles - by 3 times. The developed complex system can be used to clean the ICE gases to the level recommended by IMO.

The Influence Technological Aspects to the Formation of Defects in PbI<sub>2</sub> Single Crystals

The research of the influence of technological modes has been carried out and the negative influence of contaminating impurities on the lead iodide crystallization process has been grounded. The new technological approach to PbI2 single crystals growth has been proposed, which, unlike traditional methods, is based on increasing of the purity of the source components at the initial stage of technological process. The comparative analysis of the proposed growth technique with other known methods has been made, the efficiency of the purification operation of the Pb and I2 source components for the obtention and properties of PbI2 single crystals has been determined. The main types of defects during PbI2 crystallization from the melt have been analyzed and technological approaches for elimination of the structural violations have been proposed.

Online-calculator “A calculation of baking formula” for automated workplace of operator-technologist

Calculation of recipes of dough for bakery products is a significant and routine operation. Doughing is the main stage of technological process in bakery production. The quality of both the dough and the final product is caused by baking properties of flour and also a ratio of water, yeast, salt, sugar and cooking fat. The recipe of a bakery product is developed for the purpose of its production with the required properties due to assigned amount of components. Development of the automated calculator for calculation and correction of the recipes of bakery products is explained by the bakery technologist’s daily need in calculating the amount of components. Basic data for calculation are type, quantity and humidity of the main (flour, grain products) and additional components (sugar, butter, cocoa and others), amount of flour which is used for preparation of ferment. The technique of calculation of recipes of fermented dough and non-fermented dough is considered. There are panels for the choice of a way of doughing, for setting the amount of flour and grain products, and other components, setting additional data, and the result of calculation of recipes. The data found during the calculation of the recipe of bakery products come to the database and are used for controlling the recipes, for proper dosing. The programming language JavaScript with jQuery library is chosen. Programming is carried out in free source code editor Notepad++ The source code editor developed on the basis of Java technology has a number of advantages for industrial consumers. The main advantages are independence of the hardware platform and the operating system. Besides, development of the automated online calculator accessible on any personal computer connected to Internet network simplifies considerably the technologist’s work.

System for complex exhaust gas cleaning of internal combustion engine with water-fuel emulsion burning

The necessity to fulfill all requirements of international organizations in the field of environmental protection, need to reduce heat loss in combustion of organic fuels, increasing economy and reliability of all elements of ship's power plant make it necessary to develop complex technology. The aim of study is to develop system for complex exhaust gas cleaning of internal combustion engine (ICE). For performing tasks in technology of proposed method, providing solutions to problems of improving economic efficiency, improvement of environmental indicators and reliability, it is envisaged 5 stages of technological process. At all stages conditions for appropriate running of physico-chemical processes in the next stage are created. Possibility of solving complex problems in proposed technology is ensured by combustion of water-fuel emulsion (WFE) with specifically recommended value of water content W r = 30%. When WFE is burnt with a water content of 30%, the low-temperature corrosion intensity decreases, which allows to install a condensing heating surfaces in exhaust gas boilers. At these conditions an equimolar ratio of nitrogen oxides NO2:NO in gases is required, which is necessary to activate their absorption properties. When WFE is burnt with water content W r = 30% the metal surface with a temperature below of dew point H2SO4 passivates. Experimental studies performed show that: 1 m2 of condensing surface absorbs 3.4 mg/m3 of NOx and 0.89 mg/m3 of SO2, which makes it possible to decrease the NOx concentration by 1.55 times and SO2 - in 1.5 times. There is a process of precipitation of toxic solid ash and soot particles: from 150...170 mg/m3 (at outlet of ICE when WFE is burnt with W r = 30%) to 70...90 mg/m3 after the condensing surface. Consumption of water with alkaline properties decreases when NOx, SO2, CO2 concentration is reduced in front of scrubbers. Reducing pollution of heating surfaces increases the cleaning period of EGB in 2.5 times. The using of complex system provides efficient exhaust gas cleaning at the level recommended by IMO.

STUDY OF THE DIFFERENT WAYS OF PROTEINS EXTRACTION FROM SHEEP AND COW WHEY FOR “URDA” CHEESE PRODUCTION

The necessary stage of technological process of “Urda” albumin cheese production is whey proteins extraction from sheep whey (in classic technology of product) or from the whey mixtures, offered in the work. For whey proteins extraction from whey the following ways are used: thermal, acid, acid-alkaline and chlorine-calcium. There was established the equal dependence of the influence of the way of proteins extraction from both sheep and cow whey on the output of protein mass. The most output of protein mass (3,47±0,10 %) is at the chlorine-calcium way of proteins extraction, a bit less – 3,41±0,08 % – at the acid-alkaline way. But the acidity of such protein mass, received by the chlorine-calcium and acid-alkaline ways is not high – 37,2±1,8 and 45,6±1,4 % respectively that negatively influences the gustatory qualities of product. The least output is registered at the thermal way. Albumin cheese, received from such protein mass, was the best by its gustatory qualities. The output of protein mass from sheep whey is 1,60 times higher than from cow whey. The mass share of proteins in protein mass, received from sheep whey is by 6,9…8,0 % higher comparing with one, received from cow whey. Protein mass, received from sheep whey by the chlorine-calcium and acid-alkaline ways has the low titrated acidity. Cheese, received from protein mass, received of sheep whey by the acid method, has the extremely high acidity values (115,5±1,5 °Т), excessive sour-milk flavor and smell. These results don-t allow to provide the long storage term. That is why it is recommended to use the thermal way for proteins extraction from sheep whey and for proteins extraction from cow way in the technology of “Urda” albumin cheese. So the thermal way of proteins extraction from the mixture of sheep and cow whey in ratio 1:1 or 3:1 can be used for “Urda” albumin cheese production. The use of cow whey gives a possibility to cheapen the product because cow whey is cheaper than sheep one. Such cheese has the improved organoleptic parameters, namely homogenous consistence, tender sour-milk flavor and smell.

Solution of the problem of negative value of the linear technological size

The calculation of the linear technological sizes is one of necessary design stages of technological processes of machining. A problem is that with performance of calculation of the linear technological sizes negative value of the technological size sometimes turns out. In the article consideedr an example of calculation, in which appears negative value of the technological size. The calculation is carried out on the technique with use of the chart of processing and the computer program which is carrying out automatic construction and the decision of the equations of dimension chains. As a result of the study, it was found that the appearance of a negative value when calculating the technological dimensions is not an error, this is due to the uncertainty of the positions of the technological size boundaries before calculation.