2.7. АКРОНИМЫ - Учебное пособие Омск 2003 удк 802. 0(075)


(акроним - буквенная аббревиатура, состоящая из инициальных букв терминологических словосочетаний)

Ex. I. Translate the terms - acronyms

CAT – Computer Aided Technologies (mach); CAT – Computer – assisted trading (econ.); CAR – compound annual return (econ.); AND – Army Navy design (mach.); ARM – aircraft radio mechanic (aviat.); DAY – distributed air gap (mach.); MAD – magnetic airborne detector (aviat.); SIGMA – shielded inert-gas metal-arc welding (mach.); ACID – Automated Classification and Interpretation Data (inform.); ROAD – Reorganized Objective Army Division (mil.); MAN - Militarg Aviation notice (mil.); MASS – Modern Army Supply System (mil.); WHO – World Health Organization; SAW – Surface Acoustic Waves (elect.); SALT – Strategic Armaments Limitation Talks (mil.); ROSE – Remote Operation Service Element (comm..); DAM – Data Addressed Memory (autom.); CAP – cleaner air package (mach.); HELP – Highway Emergency Locating Plan (road.); PERT – program evaluation and review technique (comp.)

Notes to ex.1:

mach. – machinery;

econ. – economy;

aviat. – aviation;

inform. – information;

mil. – military;

elect. – electricity;

comm.. – communication;

autom. – automation;

road – road–building;

comp. – computers.



The future academician Vladimir Ipatiev was born in Moscow on November 21, 1867, in the fam­ily of a well-known architect. He received a secondary military educa­tion at a Moscow military gymnazium and, after graduating from it, enrolled in an army infantry school. During his years of military service, cadet Ipatiev completed a course on organ­ic and inorganic chemistry on his own. He received his higher educa­tion at the Mikhailov Artillery Academy in St. Petersburg, which was considered at that time to be the best higher training facility for Russian military officers.

At the Academy, Vladimir Ipatiev had a great many opportunities to study chemistry and experiment in a well-equipped chemistry laboratory. It was here, working on his own, that he achieved such fantastic success in his study of chemistry that he soon began to de facto hold classes in the subject at the Academy. His authority at the Academy became so great that its directors approved and published a chemistry coursebook written by Lt. Ipatiev, allowing him to restructure the subject's entire curriculum.

It was here too that he revealed himself as a talented scientist. Vladimir Ipatiev did not simply repeat chem­istry experiments already described, but from the very beginning sought his own, new paths, and his research were distinguished by their novelty and originality. At the Academy, he made acquaintance with such major Russian chemists as Aleksei Favorsky and Dmitry Chernov, and many others.

Having graduated from the Academy in 1892 with excellent marks, he was retained there as an instructor, and to work on his doctoral thesis.

It was during this year that the young scientist's life changed forever. Vladimir Ipatiev published his first work – a brilliant study of the structure of steel crystals, which was approved at a session of the Physical Chemical Society of Russia, and won the approval of Dmitry Mendeleev him­self. He was accepted into the Society, thus becoming the youngest member ever in the history of that organization. The young scientist saw this event as a real triumph: it meant recognition in the scientific world, and strengthened his resolve to devote himself to chem­istry.

In 1894, the 27-year-old Capt. Ipatiev defended his thesis on organic bonds, and became the youngest professor of chemistry at the Michailov Artillery Academy. Like his previous work, his dissertation was rated very highly by the leading chemists of the day, and was even published abroad.

In 1896, Vladimir Ipatiev was sent to Munich University in Germany, to continue his research in a practical with the renowned chemist Adolf von Baeyer. Under his direction, Dr. Ipatiev engineered the original reac­tion of isoprene synthesis for the first time anywhere, thereby laying the foundations for the production of syn­thetic rubber. From this moment on, organic synthesis definitively became the main line of Ipatiev's research.

Vladimir Ipatiev lived abroad for three years. After his return to Russia in 1899, the most active and productive period of his scientific work began. The promising new direction in chem­istry organic synthesis in the presence of catalysts turned out to be an unlim­ited field of study for a chemist of genius. With striking diligence and scientific intuition, Dr. Ipatiev per­formed an endless number of .experi­ments, each of them pushing forward the boundaries of science and raising it to new levels.

It was Vladimir Ipatiev who first intro­duced high-pressure methods to chemistry, having built the "Ipatiev Bomb" an apparatus, unique for the times, which became the prototype for the modem autoclave. His article on the catalytic hydrogenization of organic bonds, which marked the beginning of catalytic synthesis in chemistry, was published one year earlier than a simi­lar study by the French chemist (and, later, Nobel Prize winner) Paul Sabatier. At the same time, using the methods developed by him for initiat­ing reactions at high pressures, Ipatiev's research was more original.


Today we should give the outstanding manager and talented engineer Alexander Serebrovsky his due for his major contribution to the oil industry development. His activities in establishing mutually beneficial ties between oilmen in Russia and the USA constitute a clear example of a statewide view of the industry's problems.

By the early 1920s, the oil industry of Soviet Russia was in a critical position owing to the rapid strengthening of negative development trends that appeared at the beginning of the centu­ry, and to the destruction caused by the Civil War. This affected primarily crude oil production, which was con­stantly falling. For example, in 1901 – 11,506,100 tons of oil were produced (the maximum pre-revolutionary level), in 1913 – 10,205,500 tons and in 1917 – 8,795,000 tons, but in 1920 – only 3,849,000 tons.

Many foreign analysts viewed the future of the Russian oil industry with considerable skepticism, believing that the country would be an oil importer for a long time to come.

The prominent Soviet engineer Alexander Serebrovsky, dubbed by Western journalists the "Russian Rockefeller," was of a different opinion. This extremely interesting man had experienced major events in his life. Serebrovsky was born in 1884 in the Samara Region, in the family of a rail­way worker. After finishing school in 1900, he began working at the head railway workshops of the Samara-Zlatoust railway. Two years later, he had passed the full course of a secondary school externally, and then he was accepted at the St. Petersburg technological institute. He did not complete his degree, however, owing to the revolutionary events of 1905, in which the young Serebrovsky took an active part.

At the end of 1908, he left for Belgium, where he entered the Brussels Polytechnic School and, in 1911, graduated there as a mechanical engineer. On returning to Russia, he had a variety of engineering posts in Sormovo, Moscow and Revel (now Tallinn). In May 1920, by decision of the Government of Soviet Russia, this exceptionally energetic and widely educated man was appointed head of the Azneft trust (an abbreviation for Azerbaijan Oil Trust), which at the time produced and refined about 90 % of the country’s oil. In his strategy for reviving and mod­ernizing the Russian oil business, the engineer Serebrovsky oriented him­self on making extensive use of advanced foreign and, above all American, experience. He proceeded from the assumption that the neces­sary technical and production culture already existed in Russia for adopt­ing American innovations in the oil industry. Serebrovsky intended to use the latest American technology for turning the trust he headed into one of the most competitive oil compa­nies in the world.

A decisive role in the implementation of these plans was played by several months he spent on business trip to the USA in 1924. His aim was to establish direct contacts within American oil business community, to get to know the state of the oil busi­ness in the USA and to purchase oil­field equipment.

The trip began with a visit to the head office of the standard Oil Company, in Manhattan. The Chief Executive of the company expressed an interest in cooperating with the head of Azneft. He allowed Alexander Serebrovsky free access to all the company’s facilities and plants. In the hope of developing business relations he was even ready to render all sorts of assistance in the purchase of the latest American equipment.

Alexander Serebrovsky’s trip to the USA exerted a long-term positive impact on the development of the Azneft trust and, consequently, on the entire Soviet oil industry. On the basis of analysis of American management practices, the engineer Serebrovsky proposed organizing the work of Azneft in the manner of the leading US companies. In his opinion, granting greater independence to the regions and enterprises and their transfer to cost accounting would provide an opportunity for free development and further technical and organizational improvement at the local level. The divisional structure of the trust, as proposed by A. Serebrovsky, on the basis of analysis of the American oil companies experience, was apparently best suited to Azneft since it took into account its large size, geographical dispersion of its offices and enterprises, orientation on a broad range of petroleum products.

Thus, A. Serebrovsky has made greater contribution to the development of oil industry of the country.


As far as the use of products is concerned, stricter limits or prohibitions on the use of pollutants (meaning, for example, asbestos-free products, new exhaust emission standards) have had, and continue to have, an influence on product design and production techniques. As for waste disposal, schemes aimed at transferring more responsibility for disposal to manufacturers and traders are of particular importance.

Strict environmental regulation can be seen as a considerable disadvantage when considering factory location. Taking Germany as an example, 1.7 % of the republic's GDP was spent on environmental protection in 1991, two thirds of this by private industry. Although there is general consensus that this policy makes sense in the long run and is indispensable, we must ask if this challenge does not represent an invaluable locational advantage in the long term. Do these constraints not lead to innovations in products and processes as well as to new markets? Germany has the highest share of the world market (1990) for environmental protection technology (21 %), ahead of the USA (16 %) and Japan (13 %).

Financial estimates for solving the environmental problems inherited in the former GDR are going through the roof. Many other countries, amongst them some of Germany's immediate neighbours, are not yet aware of this situation or its consequences. No doubt all industrial countries will be faced with these challenges sooner or later. But then the efforts we are making today will give us an invaluable competitive edge, with a large market for know-how and machines for environmentally safe manufacturing processes emerging. A significant number of companies have already taken up this idea as a matter of sales policy. In both capital investment and consumer goods, progressively more purchasing decisions are being influenced by environmental considerations.

Take, for example, the field of electroplating, which because of the chemicals used, is a major hazard to the environment. Electroplating companies are obliged to invest heavily in waste disposal, in particular for drainage filtering, making it difficult to integrate the electroplating stage into the overall manufacturing process. This has led to a new approach: instead of the workpiece being transported to the individual baths for surface treatment, the 'chemical' comes - inside a sealed machine - to the workpiece. Inside the machine is a processing chamber which is filled alternately with the necessary fluids for the cleaning and separating processes. The unit manufacturer assumes the responsibility for disposal as part of the service, so that the operator is not burdened by the specific problems of an electroplating shop. He can integrate this machine into his production process and operate it as he would any other. Here, new requirements have led to new solutions and have thereby generated a forward-looking innovation.



Environmental protection is not only of constitutional importance, it is becoming increasingly more significant as an economic factor. Each year, the expenditures on environmental protection are being increased. These will continue to rise due to the growth in the existence of environmental protection systems despite a downward trend in investments.

In previous years, investments in environmental protection have also undergone a structural change which makes the necessary sums appear too low. It has been ascertained that statistics normally only take so-called “end of the pipe technologies” (i.e. connected filters and sewage treatment processes etc.) into account. At present, however, the conversion to process and product integrated environmental protection based on an environmentally friendly production process is taking place. Appropriate measures form part of modernization and expansion investments which is predominantly of advantage to the machine and plant building industry. They increase the level of environmental protection although a special arithmetical compilation would be impossible and of little use.

The high rate of investment in environmental protection has now borne fruit and this is particularly made clear by the drop in the emission of pollutants (sulpher dioxide) in Bavaria.

By ground redevelopment and the preservation of healthier air and water and of nature and the countryside may be achieved a distinct location advantage.

A further point is also worth mentioning however, i.e. the fact that not only a few industrial sectors benefit from the high expenditure on environmental protection. In addition to specialist environmental protection companies, the demand ensuing from environmental protection is also of particular benefit to the most diverse companies in the machine building and steel construction industries, electrical engineering, control technology, measuring and analysis technology, process engineering, the construction industry and the manufacturers of numerous types of apparatus, equipment, working materials and devices required in environmental protection.

Environmental protection is a growth industry and this is also demonstrated by the “investments” in organizational structures which have not yet been statistically compiled such as the dual waste system (DSD) and other disposal and recycling systems. In this respect, the processing industry will be a particularly interesting growth industry. This collective term is used to describe all companies which deal with the recycling of raw materials and/or other marketable products from refuse or waste materials and particularly companies which deal with the separation and sorting of refuse or the disassembly of used products and/or processing, refining and marketing the materials thus obtained. Environmental protection technology has good prospects and the evaluation of patent statistics Ifo-Institut für Wirtschaftsforschung has shown that Germany is the world’s leading inventor in the processing industries and surpasses the USA and Japan in practically all areas of processing technology with regard to the number of registrations. Inventions involving the destruction of solid refuse or its conversion into useful and safe items are of the utmost significance and approximately a quarter of all German inventions involving the recycling of synthetics came from Bavaria. A vast growth market is opening with regard to the prevention of water pollution.

Prospects should not only be viewed on a national level however. The European single market promises new stimuli for the environmental protection industry. In 1988, the European Community amounted to approximately DM 9.4 billion.

Surveys have shown that companies regard the sales potential in the EEC single market (with its improved prospects concerning public invitations to tender) as an incentive for intensifying activities abroad.

New politico-environmental initiatives must thus gain a foothold throughout the whole of the EEC from the start to achieve the most widespread effect possible and to prevent the local economy from having to bear onesided cost burdens and competition disadvantages. Nobody should lose sight of the discernment that every money unit invested in environmental protection must first be earned.


It is important to consider restructuring methods of paying employees in order to attain maximum financial efficiency. A study examined the relationship between piece-work and hourly pay, operating the two schemes in parallel. Initially, piece work and time-related pay schemes were operated in parallel. A survey revealed that the efficiency level for piece work was equal to the prescribed 'sound barrier', in this case 135 %. Hourly paid workers achieved between 40 and 100, and an average 70 %. So contrary to many people's expectations, the hourly-paid workers were by far the 'most expensive'. In the units, a veritable 'performance explosion' was observed amongst this group; the comparative figure is now 120 %. Lead times have fallen by 30 to 40 %. There is no longer any stockpiling of work in progress; raw material is available on call from stock, as determined by the unit concerned and not by a central administration!

The workforce is now paid according to productivity, in the form of bonuses, divided as a matter of principle equally amongst the whole group, taking both shifts together. The group has an elected speaker who has a full work load and receives no financial reward. This prevents the position of foreman from being secretly re-established, an effect which can be observed in many other examples of group working. The large reserve of potential speakers is in itself amazing; the figure is over 50 %. The fear which is occasionally expressed that the pay scheme in such a group must result in a harsh social climate, is not borne out here. The performance differentials which inevitably arise do not result in individuals being ostracised, which must be due at least in part to the attention paid to human factors.

Meetings of all unit employees take place at regular intervals, as a rule weekly, and notes of these meetings are taken as a matter of principle. They deal mainly with efficiency improvements, since these are in the natural interest of the employees. Work is currently under way to establish a corporate model in which each employee's self-image and that of the company are expressed to the customers.

It should be clear by now that the solutions of the future can not be 'bought off the shelf, but must be pioneered. A process of change in awareness and behaviour must be given priority over the use of technical aids. In many cases we are still at square one. Only if corporate management works unequivocally towards this goal will it be possible to mobilise middle management and staff. This requires a reappraisal on the part of all concerned, a process which will be wearisome and in part painful, but which is absolutely essential. History teaches us that structures and organisations which are only concerned with hanging onto power and which no longer offer new ideas and solutions, will sooner or later disappear and be replaced by new ones; it this that industry, through innovation, must endeavour to avoid.


The skilled trades together make up Bavaria's most diverse and – after industry – its second largest economic sector. In 1992, Bavaria's 140,000 craft businesses and their 1 million employees achieved an annual turnover of approx. DM 165 billion, this representing approx. 12,5 % of Bavaria's gross domestic product. These efficient and modern businesses which cover 127 different skilled trades make a major contribution to the success of the Bavarian economy. After all, one of the main reasons for Bavaria's (unprecedented leap from a primarily agricultural land to one of Germany's leaders in both economic and technological terms is the fact that Bavarian business is made up not only of large corporations operating on an international scale but also of numerous modern and highly dynamic small and medium-sized businesses.

Thanks to their diversity, the skilled trades are both active in and vital to virtually every branch of industry: In building and finishing, metalworking, woodworking, textiles and the clothing industry, the food industry, health and body care, industrial cleaning and in glass, paper and ceramics. The skilled trades perform countless important functions in both the economy and in society at large.

The skilled trades and economic pro­gress:

The skilled trades are flexible, creative and innovative. They both generate and act upon new ideas, putting these into practice fast without any bureaucratic delays. That's why so many new business develop­ments start life in the skilled trades.

The skilled trades and new technologies: It goes without saying that craftsmen avail themselves of state-of-the-art technologies in addition to their traditional tools and methods.

The skilled trades and environmental protection:

The skilled trades are helping to put into practice a professional and effective attitude to environmental pro­tection. Take car mechanics, for example, who have an important role to play in the reduction of car exhaust fumes or the construction industry and related trades for whom energy conservation in building and heating systems has become a watchword.

The skilled trades and the division of labor:

The skilled trades perform numerous important supply, service and finishing functions for other branches of industry. These range from the supply of quality precision parts to the maintenance and repair of machines and the cleaning of buildings.

The skilled trades and customer proxi­mity:

Thanks to their decentralized and demand-oriented structure, the skilled trades are able to respond particularly well to individual requirements and thus to ensure a wide range of highly differentiated, quality products and services geared to the demand.

The skilled trades and tradition:

Craftsmen have always been both the creators and preservers of Bavaria's very rich and multifaceted traditions. This applies not only to the builders of Bavaria's churches and royal residences but also to gold and silversmiths, wood carvers and the brewers of Bavaria's world-famous beer.

The skilled trades and society:

The characteristics typical of craftsmen, such as accountability for one's own actions, industriousness and a sense of one's responsibility to society, are indis­pensable if our social market economy and free and democratic society are to work. Bavaria's self-employed craftsmen, therefore, are a kind of compensatory force of the center, and that not only in economic and political spheres but also in society at large.

At first glance, the skilled trades in Bavaria do not appear to have profited from the export opportunities opened up by the European Single Market and the new markets in what used to be Bavaria's Eastern Bloc neighbors. This is because traditionally, they cater above all to local and regional requirements. At present, exports account for only 3 % of the skilled trades' collective turnover. As a recent survey indicated that over 50 % of Bavaria's craft businesses believe their products stand a good to fair chance on the European market, however, it looks as if this state of affairs will change very soon.

For the skilled trades, increased inter­national cooperation means above all an expansion of their sales and supply mar­kets for both goods and services, additional demand for quality products, increased supply work as a result of the industry's continued policy of contracting out whenever possible, increased opportunities to bid for public contracts and the possibility of obtaining additional manpower and a new generation of workers. An increase in inter­national joint ventures on the part of small and medium-sized craft businesses would also strengthen this sector of the economy, this being a positive development for all countries concerned. After all, the health and efficiency of this sector are ultimately essential to the unification of Europe in freedom and prosperity.


What is the role of the employee in an increasingly automated working environment? Jean Heymans of CECIMO examines the consequences -and costs - in terms of technical development and manpower.

The Luddites had a point. In the short term mechanisation has nearly always led to unemployment. But we recognise that over a longer time scale engineering innovation is a prime mover of industrial development and therefore of economic growth. Still, in these days of global competition and obstinately high levels of unemployment in the developed economies, 'automation' is once again seen as a threat to manufacturing jobs.

This view may be too pessimistic. Jean Heymans, Secretary General of CECIMO, thinks that the replacement of shop-floor workers by machines may have reached the optimal point: 'The more electronically-driven machine tools have in the past diminished the workforce at the end-user point. I don't think this is going to continue, however.'

There might even be a slight move in the opposite direction. 'The general tendency in the early eighties was towards big, flexible machining systems. What you see now are more stand-alone machines with very quick transfer of parts from one machine to another to achieve a better product in a simpler way.'

The machine tool industry is a good barometer of the state of the manufacturing industry as a whole. 'In our sector I'd say we are now picking up and employment is increasing slightly. It's a good sign,' says Jean Heymans.

This guarded optimism was reflected in the CECIMO-sponsored 1l.EMO Fair held in Milan in May 1995. 'The fair was very successful because of the quality of the visitors. In comparison with previous fairs there were fewer people, but companies had sent decision-makers with their staff, making meetings much more efficient. This is something we have observed world wide. It's encouraging because exhibitors lose less time and in Milan we were able to shorten the fair by one day.

'Among the technical developments, the most important ones concerned speed - speed in tool changes and in making the pieces and the development of linear motors. In the past there was a tendency to over-engineer machinery. This has changed to having simpler machines that really answer the needs of the customer. Modularity of machine tool parts is a developing tendency.

One of the oldest mechanical enterprises is WARKA. The basic production profile of WARKA includes:

The Warka Mechanical Equipment Works has a 100 year history. The Building Fix-

tures and Metal Casting Factory – the Lubert Brothers Inc. was established in 1891. Initially, the basic production consisted of various kinds of building fixtures. New products and technology were added in time: machine tools, drills, planning, screwing and sharpening machines, and rolling bearings testing machines. The years 1962 and 1963 saw the introduction of complex machine tool sets and complete technological-production lines. They supply our products to, among others, the FSM car factory in Bielsko Biala, the URSUS tractor factory and arms industry enterprises.


The market for tool export is shifting from Europe to the US and Asia-Pacific, with CNC and full service packages occupying an increasingly important position in market sales.

Machine tools are fundamental to the manufacturing process of any company and therefore occupy a strategic position at the heart of any industrial nation. They are the 'master' or 'mother' machine, with every manufactured good being made either directly by a machine tool, or by a machine that was made by a machine tool. As such the industry has traditionally been a barometer for the health of the economy. When machine tool investment is increasing companies are looking ahead, planning to expand or cope with increased demand. Conversely, when recession occurs, investment is the first item to be cut and as a result the industry tends to suffer tremendous cycles of fortune. Yet no piece of capital equipment is more important to the development of companies and their products, and the capacity to invest in such technology should be a fundamental concern for policy makers.

The machine tool industry has faced considerable restructuring over the last fifteen years in the face of two steep recessions, technical change and the advent of increased European legislation. The strong cyclical movement in demand for machines is a reflection of the industry's heavy dependence on investment demand, particularly in the capital goods sector which is its main market.

The UK machine tool industry which comprises the cutting, forming and processing of metals spans a wide spectrum of users, covering aerospace, automotive, defence and general engineering as well as any industry directly or indirectly involved in the manufacturing process. The aerospace and automotive sectors account for around 45 per cent of machine tool purchases in the UK.

The world machine tool market is now dominated by Germany and Japan who between them account for around 50 per cent of world production. Japan in particular has seen sharp growth from 5 per cent of the world market in 1970 to 25 per cent in 1995. The UK remains a significant supplier of machine tools, however, being the world's eighth largest producer and seventh largest exporter.

Technical developments have dramatically changed the structure of the machine tool industry as many manual operations have now been replaced by an electronics-based solution, undertaken by CNC machines which are capable of performing several different operations with tools automatically changed in a pre set sequence. Indeed the life cycle of machines is becoming ever shorter as the power of computers continues to increase. Machines are now likely to become obsolete within three to five years if they are not upgraded or replaced.

The development of technology within the machine tool industry continues to be increasingly sophisticated with machines capable of working to an accuracy of thousandths of a millimetre up to panels the size of aircraft wings. The major areas of development at present affect lasers, high speed machining up to 50,000 rpm and new materials which may in time supplant metal as a core material. Ceramics and plastics for example are being developed for use by the aerospace and automotive industries.

In some areas British machine tool technology leads the world, such as in probes and sensors, coordinate measuring devices and grinding and laser technology.

The outlook for the machine tool industry is dependent on a recovery in investment, not only in the UK but in the major industrial countries throughout the world, following the slump during the period 1990-1993. Although the climate has undoubtedly improved recently, continuing weak demand in Europe, particularly in the aerospace and defence sectors, will delay the growth in demand for capital goods and machine tools in the short term. However the combination of a competitive exchange rate, low interest rates coupled with sustained productivity growth ahead of most competitors should underpin the competitive position of most UK producers lifting their long term prospects.

In the UK manufacturing investment remains by common consent significantly below the levels of our major competitors and at present there appears to be little acceptance among policy makers that such a problem exists despite its acceptance amongst most commentators. With such investment, particularly in high technology goods, the UK would be able to take advantage of its other competitive leads. Without it we face the dual problems of increased inflation due to capacity pressures and, inevitably, a loss of quality.


Mike Judd and Keith Brindley of SMART give an insight into all that is new and exciting in the world of soldering.

In SC soldering processes, the component is placed on the printed circuit board at a later stage than solder and flux. At a later stage still, heat is applied. In a nutshell, then, SC soldering processes involve three distinct stages:

This separation of solder application from the application of heat (both go together in CS soldering process - and cannot be split because molten solder in a CS process itself supplies the required heat) effectively means that application of solder, in practice, becomes an assembly process rather than a soldering process. Readers are referred to Chapter 2 for a discussion on methods of solder paste application.
Heat application

There are only three basic ways of transferring heat; conduction - hot liquid, hot belt, heated collet; convection - hot air, hot gas, hot vapour; radiation -infra-red, laser, light beam.

Processes may be a combination of two or all three heat transfer methods but only two of these (infra-red and hot vapour) are used to any great extent.

Both infra-red and hot vapour soldering machines have been developed to such an extent there is really very little to choose between them. Both processes (at least their state-of-the-art variants) are capable of soldering densely-populated printed circuit assemblies to a high level of performance, and with few defects.

Laser soldering is currently in late developmental stages, and shows great promise for specialised SC soldering of surface mounted components. At present it is more costly than infra-red and hot vapour soldering processes, but it may find a niche market for soldering individual components which cannot easily be soldered by other mass means.
Infra-red soldering

Infra-red (IR) soldering processes have developed rapidly in recent years since their first introduction. Main developments of infra-red soldering machine processes with time are:

Generally, infra-red soldering machines direct infra-red heat onto the board from above and below. Radiating elements have built-in thermocouples to allow temperature control. Heat transferred onto the assembly and so temperature of the joints to be soldered, however, depends on the materials and shapes of the board and components as well as wavelength of the infra-red radiation. For this reason, in such a basic infra-red machine it is difficult to be sure that all joints reach the same temperature at the same time. The effect of different joint temperatures is known as the shadow effect.

In operating terms, the shorter the wavelength of the infra-red element the more likely are boards and small components to suffer from overheating. On the other hand, more uniform heating of solder paste is obtained with short wavelengths.

Longer wavelength elements have an advantage in their air around them is heated. This hot air provides heat to assemblies by convection means. If hot air is allowed to aid heating of assemblies naturally the process is known as infra­red radiation with natural convection heating. The addition of convection heating to infra-red radiant heat soldering machiners tends to give more uniform heating and reduce temperature differences between joints on assemblies.

This principle of using convection heating to reduce air temperature differentials is extended by forcefully circulating warmed air to provide forced convection heating. It can be extended further by forcing air through perforations in each infra-red panel emitter, such that it is distributed evenly over the assembly surface. In this way, high volumes of airflow can be generated at quite low velocities. In general, the higher the volume of forced airflow the smaller the difference between joint temperatures across an assembly. A further advantage of forced convection is the lower infra­red emitter temperatures required.

By dividing the infra-red soldering machine into distinct and isolated zones, each of which use forced convection, greater control over assembly joint temperatures is available. Typically, air is taken into a zone from the assembly area, recirculated then diffused through heater elements back to the air intake. This effectively segregates each zone from its neighbour and gives a high degree of temperature isolation and controllability. Control of assembly temperature within such a soldering machine is achieved simply by standard computer and electronic closed-loop control principles, allowing high degrees of accuracy and adjustment.

Air is not the only gas which can be used in convection infra-red SC processes. An inert gas, say, nitrogen, can easily be incorporated into the system instead.

The ability of infra-red soldering machines to produce perfectly soldered assemblies depends on temperature uniformity over all the joints to be soldered. As an assembly passes through a soldering machine, the ideal is to maintain a constant temperature at all joints across the assembly; in other words there should be no difference in temperature between any two points on the printed circuit board. This elimination of temperature differential is often known as a zero.

Temperature differentials between joints can be caused by a number of factors, including:


assembly surface;

supporting arms.
Hot vapour soldering

Hot vapour soldering processes saturated vapour, condensation, or vapour phase (VPS) soldering processes.

Although classed here as a convection form of heating, heat transfer in a hot vapour soldering process takes place when a saturated vapour condenses on the board, and is thus a product of the liquid's latest heat of evaporation. If a liquid is selected with a boiling point of that required to convert the solder paste into molten solder (around 215°C to 230°C), then once that temperature has been reached, no further condensation can take place so no further temperature rise can occur. Upper temperature control in the process is therefore simply not required - a significant advantage over other SC soldering processes, particularly those using infra-red heating elements.

In turn the equipment, in principle at least, is extremely simple. All element heats the liquid to boiling point, while the assembly is positioned in the resultant vapour above the liquid. Liquid used is a perfluorocarbon (this is no environmental threat). Times to reach soldering temperature range from as little as just 5 or 6 for small joints, to around 50 for large joints. The vapour also removes flux and flux residues in a washing action after soldering has taken place, reducing the requirement for post-assembly cleaning.


4.1. Порядок слов в предложении

В отличие от русского предложения со свободным порядком слов английское предложение имеет твердый порядок слов, который можно представить схематически следующим образом (см. рис. 1, 2):

Подлежащее + сказуемое + дополнение




Рис. 1

или сокращенно: