- Email: [email protected]
Science and technology in the new millenium
7 Science and technology in the new millenium
Science and technology are full of surprises, and at no other time in history have they radiated such rich potential. The only certainty is the extent and speed of change. The transistor is 50 years old, but the microprocessor, which is based on it, is just 27. The Internet is 30, but the World Wide Web is not 10 years old. Microchips are everywhere.. 'Just as we are still feeling reverberations from the invention of the international combustion engine, we will be feeling the impact of the microchips for countless generations to come' says Paul Saffo, director of the Institute of Future, a technology think tank in California. But if you think computers have already changed your life, fasten your seatbelts. By 2020 the desktop PC will be replaced by millions of microchips embedded in everyday objects; cars, furnitures, machines, tools, etc. Switches and buttons will soon be replaced by 'smart' sensors and voice activation devices. Sensors in your refrigerator will tell the supermarket to deliver items you are running short of. You will jump in your car and sensors will adjust the seat, steering wheel, mirrors and air conditioning to your requirements. The logistic systems in manufacturing and production will also be based on sensors. Last minute supply is a normal procedure. 'Cheap microsensors and voice recognition will shape the next phase of the computer revolution', Saffo says. 'Sensors will allow computers to penetrate every aspect of our lives, while receding into the background. This will be the age of calm computers; computers that adapt to us, rather than we to them. Today's PCs will seem comically clunky to future generations.' Meanwhile, smart sensors in buildings and bridges will detect stress and warn of potential structural failures. The evolution of sensing technologies will culminate in a single chip that will store technical records, data, procedures, solutions, etc. In the 21st century, life and work will be made easier by servant robots also in the workplace. Robotic 'pets' - special purpose automation - will undertake mundane tasks and will be far more efficient than androids mimicking humans, predicts Prof Marwan Jarbi, professor of adaptive systems 129
130
The welding workplace
in the department of engineering at Sydney University. Duplicating our intelligence will be the great challenge of the 21st century. The information society will create a new economic and social order in the 21st century, much of it based on the Internet, says John Patrick, vicepresident of Internet technology for IBM: 'The Net is that rare technology that only crops up every 100 years or so, where reality really does exceed hype. We are at the start of an information explosion.' That explosion will thrust the Internet into a multitude of new places, bringing the world's knowledge, in sound and vision, to places as small as your wristwatch. The amount of information on the Internet - already doubling every year - will be so colossal that you will need holographic researchers to guide you to the information you want. Within 20 years active contact lenses will allow you to surf the Web and acquire your e-mail without even opening your eyes. As scientists learn more about the construction of atoms and molecules, they will also discover a flood of new materials. The invention of plastics in the 20th century will be far surpassed by the development of new environmentally-friendly alloys such as double strong steel and aluminium. Although oil supplies are unlikely to run out within the next 100 years, the hunt for a clean, cheap and inexhaustible source of energy will become imperative as environmental issues become more and more pressing. It is unlikely that 'cold fusion' - a low-temperature nuclear technology that promises vast, cheap power - will materialize as a viable energy source, even by the late 21st century. Fusion research is being scaled back dramatically worldwide, because of a growing consensus that it is technically impossible. Not to worry, says Dr Don Hutton of the department of physics at Melbourne's Monash University. 'Our consumption of energy should fall with more efficient technology. By the time China is fully developed, its consumption of energy should be no more that the US at the present time. There will also be a slow shift from fossil fuels to renewable energy sources: solar and wind power.' Where are we going with science and technology in arc welding? It is of course predictable that mechanization and automation will follow the next phase of the 'computer revolution'. Further design and development of sensing systems in combination with automated welding are expected. Progress in electronics for process steering, the control systems for guarding the welding parameters during welding and the welding process, are important for quality aspects and product responsibility. Welding equipment will be more compact, easier to access and smarter in use. Welding and cutting robots will be smaller, more user friendly and less costly. Welding sensors will be able to maintain the proper accuracy for a specified welding process, free from the influence of welding process - induced disturbances (such as light, heat, fume, spatter and electromagnetics),
Science and technology in the new millenium
131
satisfactory durability, low cost, easy maintenance, compact size and light weight, and a wide applicability range. The sensors which should make most progress in welding are optical sensors followed by arc sensors. The control system, which will reach a high level of development, is the adaptive control system for arc welding. Computerized welding mechanization and automation will be common and also used in smaller welding workplaces. The development of new construction materials, like environmentally friendly alloys, such as double strong steel and aluminium, will become usual.
7.1
Paradigmatic shift in robotic manufacturing towards the virtual manufacturing plant [1] Background
Welding technology is the most complex technique that we know. It started nearly six thousand years ago (Mos.l, 4:17-22) with the blacksmith Tubal-Kain who was manufacturing all kinds of tools from copper and iron, by forgewelding. In the beginning of the 19th century (5900 years later) shielded metal arc welding (SMAW) was introduced. From that time welding technology development has rapidly increased and we have seen a small paradigmic shift over the century. The development of steel together with the development of processes has resulted in new products and new improvements. Reports reveal how to find new solutions to unknown problems by scientific research. Other technologies have been developed in parallel such as electronics and computers, leading to the first robot in 1974. Increasing demands on productivity, safety and quality have led to more automation and thereby more complex processes. Faster, cheaper and better are the words that we hear every day. However, they are explained in more exact terms like: • • •
Cut the product development time from four years to two years. Reduce costs by 5-8% each year during the next five years. Improve the quality to World Class, ISO 9001 and EN 729-2.
The welding process itself becomes a part of a whole system, far away from what Tubal-Kain ever could have dreamt of.
Introduction Today's technology has come to a level where these goals can no longer be reached without involving the whole company. Welding technology must be a part of this development which means that existing tools and systems must
132
The welding workplace
be able to 'talk' with new systems that are to be developed. The future will be even more complex where communication, education and changes of organizations are the key issues for success. What are the alternatives? There is no doubt that if we are not successful in our development of welding production it will happen in the low cost countries and we must fully appreciate this fact. The globalization of companies is developing rapidly and purchase departments can show figures that are very hard to compete against. Our future lies in new technologies which can reach the goals that are set up. This means that we are going to meet a paradigm shift within the coming eight to ten years - it has already begun!
Paradigm shift A paradigm shift is defined as a major change in the way things are thought about, especially scientifically. Once a problem can no longer be solved in the existing paradigm, new laws and theories emerge and form a new paradigm, overthrowing the old if it is accepted. To abandon one paradigm for another is to alter the entire intellectual basis of a community whether it be scientific, political or otherwise. It represents a profound change in the thoughts, perceptions and values that form a particular vision of reality. Paradigm shifts are usually brought about by people who are young or new to a particular discipline since they are relatively free of established preconceptions. A paradigm is the consensus of the scientific community, where the professions have come to accept concrete problem solutions. The concept of paradigm has two general levels. The first is the encompassing whole, the summation of the parts. It consists of the theories, laws, rules, models, concepts and definitions that go into a generally accepted fundamental theory of science. Such a paradigm is global in its character. The other character of paradigm is that it can also be just one of these laws, theories, models, etc, that combines with others to make up a global paradigm. For instance, Galileo's theory that the earth rotated around the sun became a paradigm in itself, namely a generally accepted law in astronomy. Yet on the other hand, his theory also combined with other local paradigms in areas such as religion and politics to transform culture. In 1974ASEA (now ABB Flexible Automation) introduced the first electrical microcomputer controlled robot. Since that time development has been rapid and today we are entering the virtual manufacturing world. During the past 25 years industry has followed the development by investing in new techniques and thereby reducing manpower as well as shortening lead times quite extensively, Fig. 7.1. Facilities have become more complex and changes in products and production are now very difficult
Science and technology in the new millenium
133
Year 2000+ Present level
-~~~~~~~~~~~~~~--------------l
l
I
I I I I
rnanufacturinq plant I I I I I
1990 Robot IV
lI
! The virtual!
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1985
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1995
I I I I I
Off-line programming: aLA CCD camera
I
Robot II
!
CAD
I Robot I
1974
I
!
Robot III Seam searching and tracking ,---_ _+--_----' 1980
1975
!
! I I
25 years in steps of 5 years
1997
2000 10 years-~
12006 2010 l
7.1 Robot arc welding development during the past 25 years. Today we are entering the new paradigm, the virtual manufacturing plant.
because of unforeseen bottle necks. Welding automation is in this respect harder to introduce than automation in machining since welding involves heat deformation. Such a bottle neck came into existence in 1990 when a new robot installation was programmed. The complexity of the robot combined with the complex weld structures led to a total on-line programming time of approximately 500 hours! This was of course unacceptable and off-line programming was the solution. Today the down time of the robot for such programming is some 25 hours! However, off-line programming was not that simple. It required a 3D CAD model from both the design department (the weld structure), fixtures and the robot supplier. These models, at that time, were not good enough to use and therefore they had to be developed so they could fit in to the whole system, Fig. 7.2. Sharing data between different departments and databases in a global perspective will be the next challenge. Much work is going on around the world on this subject not least in the US Space Shuttle Program, as it was some 35 years ago! Industries will of course in the near future see and use some of the inventions that develop, Fig. 7.3. Over the last 25 years heavy investments have been made in robot facilities as well as in new weld structures. New investments will be even more
134
The welding workplace 3D-CAD FEM Calculation
Intergraph/EMS 3D solids (Solid edge)
3D-CAD Fixtures
Database
IEP
Processes Welding of frames QA ISO 9001 EN 729-2
Simulation Off-life programming RobCad Ver. 3.5.1 Silicon graphics
MRP IBM AS 400 MAPICS
Purchase External suppliers of robot systems B&C, IGM, ABB
TDL UNIX or PC
Ingoing parts in the product
Production process Plate and welding fabrication of frames
7.2 Information and data flow in the process of weld structure development has to be improved to meet next generation requirements.
expensive and requirements are so high that it is more or less impossible to foresee what the consequences will be unless you can see it in 'reality'. A change in one corner of the plant can show good results but in another corner it might create problems. Virtual reality simulation is a part of the new paradigm using suitable models, Fig. 7.4. To reduce arc time, high speed welding i.e rapid melt, double wire welding, time process, etc, will increase in use. Simulation of the whole process will be of great importance in order to verify the process as well as the equipment, etc. How to document the fabrication is another important issue which will be required according to standards and quality assurance documents. In the globalization process it is vital for companies that new innovations are implemented as fast as possible to other fabrication plants and used as standard. The conditions at various plants are different around the globe. Therefore it is important to simulate different alternatives. Communication between companies will be crucial for how successful the companies will be.
Science and technology in the new millenium
,?
Changes in the history of the Arvika Plant
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7.3 History shows that change is a permanent state.
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7.4 Virtual reality simulation is a part of the new paradigm using suitable models.
136
The welding workplace
7.2
Robotic welding systems in the year 2000 [2] - fit for human beings!
'Complete automation whereby all human labour is replaced by automated production'. This has long been the aim of industry. Two decades after the introduction of microprocessors, a lot has been achieved, but a more realistic view of the possibilities, and especially impossibilities has formed. We cannot deny, that although automation can reduce the human effort needed in a production process, it will not completely replace the need for a brain on the shop floor. Although desirable, and also possible in a technical sense, it has proven impractical to remove the last operator completely from a production process. The modern design and implementation of robotic welding systems therefore is not concentrating only on strictly technical matters. The system functionality must include the human factor as an integral part of the production system. In the automated production systems supplied by Kranendonk, the operator does not serve merely as an 'intelligence server' to the production system. He is in control. The automated equipment is the tool of the operator. When we consider welding processes, the following advantages of robotized processing are evident: • • • •
Robotization removes the worker from the welding area, which improves health conditions, Fig. 7.5. Repetitive strain injuries due to work in bended, kneeling or overhead working stances are avoided. The welding area can be closed off from the human workers for UV light, smoke and noise protection. Better fume extraction can be accomplished.
700
1000
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7.5 Welding under cramped conditions (courtesy of Kranendonk Automation BV).
Science and technology in the new millenium
137
These advantages were first recognized and used in series production. In shipbuilding, one-piece production is typical. Besides this, the sheer size of workpieces has stopped many yards from using robots for welding of sub-constructions and sub-sub-constructions. The conditions under which welding in ship constructions has to take place are often more difficult than in series production for part welding. The benefits of robotized welding systems are therefore much greater. As an example, welding of double hull section blocks in the shipbuilding industry can be observed. These blocks consist of a bottom panel with several vertical 'webs' placed longitudinally and laterally. This way, a number of boxes are formed, which are only open from the top. The construction requires substantial welding. The classic way of production involves a welder who has to climb into one of the boxes, carry his welding equipment along, and perform the welding inside the box. Automation of this job offers substantial benefits. Not only is the actual welding performed by a robot, but the entry of the welder is replaced by movement of the robot, complete with welding equipment, into the box, suspended from a large gantry. The 'mechanical' ergonomical aspects of this type of automation are clear. Having replaced the human labour with machine labour, the emphasis of the operator task will be the operation of a computer integrated production system. A whole line of processes is involved, ranging from the CAD design of the double hull sections, through work preparation, production control to the actual control of the equipment. Carefully implemented computer integration in this part adds to the user-friendliness of the system. A second, related example is the cutting of profiles carried out in many shipyards. Today, productivity and efficiency of the profile production is a very important factor. This has caused shipyards to move away from conventional autogenous cutting to plasma cutting technologies. The latest dry oxygen plasma cutting processes are hardly fit for manual cutting for the following reasons: • • •
The weight of the torch makes manual handling difficult The cutting process produces much smoke, noise and No, gases Like welding, the process emits strong UV radiation.
The dry oxygen cutting process offers faster processing, and very good product quality but can only be used in an automated environment. In shipbuilding, the manual cutting shop is replaced by an automated robot profile cutting line. Instead of worsening the environment for the cutting operator, it has been improved significantly on the following points: •
The torch is handled by the robot i.e. the operator is removed from the process yet remains in full control.
138
• • • • • •
The welding workplace
Programming of the robot is automatic, off-line, via a CAD/CAM connection. Enclosing the cutting area in a soundproof cabin offers excellent noise shielding, not only for the operator, but also for the entire environment. The process can be monitored through windows in the enclosing cabin. Special coating blocks the UV radiation. Scrap can be disposed of centrally. The cabin has efficient fume extraction with centralized filter units for dust and smoke. Observation cameras can be installed to optimise the operator's view on the cutting process.
Computer integrated systems are not yet commonplace in the shipbuilding industry. In many shipyards, the hull prefabrication processes are still the work of real craftsmen. Implementation of computer integrated technology must therefore be done in a careful way. Even though the high level of automation is only achieved through computer integration, the computer systems themselves should not be too much in the foreground. The former steel workers usually have no desire to be trained as computer technicians. It is important to use the capabilities of modern computer technology to create an operator interface that makes operating procedures as simple as possible. As an example, the production data required to control a profile cutting robot system does not look very appealing, see Fig. 7.6. The use of a graphical user interface offers the possibility to directly show the resulting shape of the cut as defined within the control system. Modern operating systems also allow more than one task to run from one computer station. Several tasks can run in separate windows. This eliminates the need for several separate terminals or control stations. S,A111 P,A1738-R,HP180X10,3120,3,TACKWELD ONLY B,50,100,950,100,70 B,900,100,1800,100,50 B,1750,100,2650,100,30 B,2600,100,3100,100,10 e,l 0,3 M,B-P4-L, 50, 60 I,1000, B-RATH, 100, 50 I,2120, B-RATH, 100, 50 M,B-P4-R,50,60 7.6 Example of production datafile (courtesy of Kranendonk Automation BV).
Science and technology in the new millenium
139
Computer integrated robot welding and cutting cells allow for further integration of work preparation processes, see Fig. 7.7. This reduces the number of human actions required to operate the system. It offers a local work preparation station (LWP) for each one of the production lines in the system, and one central work preparation system (CWP) integrating the production control and logistics control of the various lines. This distributed method of production automation offers both a high level of automation and the flexibility required in a production environment. The high level of automation allows the hull fabrication to be performed by very few people, having control jobs rather than menial work. On each level of the control system, the system handles a relevant part of the production data. In the central work preparation office (CWP) most of the work concerns planning activities: • • •
Selection of which jobs are to be executed in the next shift or day. Transfer of the production data from the yard's host system. Releasing the data for production.
In the local work preparation offices, production data for each of the production lines can be modified. For instance, a 'rush job' can be manually entered and production of the job started. On the shop floor, production is monitored. The welding expert on the shop floor has access to the database of process parameters that the automation system uses to assign process parameters for the welding system. This implies that in the design and work preparation phase of the production process, welds are described by their physical specifications (such as throat height, etc) and that the translation of the specifications into actual process parameters is automatically done on the shop floor, where direct feedback (through the welding engineer's observation or through automated process monitoring equipment) is possible. The human insight is in this way used in combination with the automated data system, which allows even less straightforward welding jobs to be carried out by such an automated system. A final but important aspect of ergonomy in automated production systems is not built into the system as such, i.e. the way in which the new system and new operational procedures are introduced and implemented in the end user's plant. It is not only important to train the actual operators in the operation of the equipment and software, but also to supply these personnel with sufficient background intormation to create an understanding of what is going on within the system. In addition, experience has shown that it pays to train people who are not directly involved with the new system, but whose jobs will be affected by it. Creating understanding helps tremendously to integrate the new production system into the existing production.
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Science and technology in the new millenium
141
The difference in automation per se, and the successful implementation of automated production systems is that in the latter, the place that humans take is carefully considered. Then, not only does automation work but the system is a place fit for humans to work in.
References 1 Hans Brostrom, Volvo Wheel Loaders AB, Sweden, IIW Document XII-1526-98. 2 Kranendonk Automation Systems AB, Netherlands.
Science and technology are full of surprises, and at no other time in history have they radiated such rich potential. The only certainty is the extent and speed of change. The transistor is 50 years old, but the microprocessor, which is based on it, is just 27. The Internet is 30, but the World Wide Web is not 10 years old. Microchips are everywhere.. 'Just as we are still feeling reverberations from the invention of the international combustion engine, we will be feeling the impact of the microchips for countless generations to come' says Paul Saffo, director of the Institute of Future, a technology think tank in California. But if you think computers have already changed your life, fasten your seatbelts. By 2020 the desktop PC will be replaced by millions of microchips embedded in everyday objects; cars, furnitures, machines, tools, etc. Switches and buttons will soon be replaced by 'smart' sensors and voice activation devices. Sensors in your refrigerator will tell the supermarket to deliver items you are running short of. You will jump in your car and sensors will adjust the seat, steering wheel, mirrors and air conditioning to your requirements. The logistic systems in manufacturing and production will also be based on sensors. Last minute supply is a normal procedure. 'Cheap microsensors and voice recognition will shape the next phase of the computer revolution', Saffo says. 'Sensors will allow computers to penetrate every aspect of our lives, while receding into the background. This will be the age of calm computers; computers that adapt to us, rather than we to them. Today's PCs will seem comically clunky to future generations.' Meanwhile, smart sensors in buildings and bridges will detect stress and warn of potential structural failures. The evolution of sensing technologies will culminate in a single chip that will store technical records, data, procedures, solutions, etc. In the 21st century, life and work will be made easier by servant robots also in the workplace. Robotic 'pets' - special purpose automation - will undertake mundane tasks and will be far more efficient than androids mimicking humans, predicts Prof Marwan Jarbi, professor of adaptive systems 129
130
The welding workplace
in the department of engineering at Sydney University. Duplicating our intelligence will be the great challenge of the 21st century. The information society will create a new economic and social order in the 21st century, much of it based on the Internet, says John Patrick, vicepresident of Internet technology for IBM: 'The Net is that rare technology that only crops up every 100 years or so, where reality really does exceed hype. We are at the start of an information explosion.' That explosion will thrust the Internet into a multitude of new places, bringing the world's knowledge, in sound and vision, to places as small as your wristwatch. The amount of information on the Internet - already doubling every year - will be so colossal that you will need holographic researchers to guide you to the information you want. Within 20 years active contact lenses will allow you to surf the Web and acquire your e-mail without even opening your eyes. As scientists learn more about the construction of atoms and molecules, they will also discover a flood of new materials. The invention of plastics in the 20th century will be far surpassed by the development of new environmentally-friendly alloys such as double strong steel and aluminium. Although oil supplies are unlikely to run out within the next 100 years, the hunt for a clean, cheap and inexhaustible source of energy will become imperative as environmental issues become more and more pressing. It is unlikely that 'cold fusion' - a low-temperature nuclear technology that promises vast, cheap power - will materialize as a viable energy source, even by the late 21st century. Fusion research is being scaled back dramatically worldwide, because of a growing consensus that it is technically impossible. Not to worry, says Dr Don Hutton of the department of physics at Melbourne's Monash University. 'Our consumption of energy should fall with more efficient technology. By the time China is fully developed, its consumption of energy should be no more that the US at the present time. There will also be a slow shift from fossil fuels to renewable energy sources: solar and wind power.' Where are we going with science and technology in arc welding? It is of course predictable that mechanization and automation will follow the next phase of the 'computer revolution'. Further design and development of sensing systems in combination with automated welding are expected. Progress in electronics for process steering, the control systems for guarding the welding parameters during welding and the welding process, are important for quality aspects and product responsibility. Welding equipment will be more compact, easier to access and smarter in use. Welding and cutting robots will be smaller, more user friendly and less costly. Welding sensors will be able to maintain the proper accuracy for a specified welding process, free from the influence of welding process - induced disturbances (such as light, heat, fume, spatter and electromagnetics),
Science and technology in the new millenium
131
satisfactory durability, low cost, easy maintenance, compact size and light weight, and a wide applicability range. The sensors which should make most progress in welding are optical sensors followed by arc sensors. The control system, which will reach a high level of development, is the adaptive control system for arc welding. Computerized welding mechanization and automation will be common and also used in smaller welding workplaces. The development of new construction materials, like environmentally friendly alloys, such as double strong steel and aluminium, will become usual.
7.1
Paradigmatic shift in robotic manufacturing towards the virtual manufacturing plant [1] Background
Welding technology is the most complex technique that we know. It started nearly six thousand years ago (Mos.l, 4:17-22) with the blacksmith Tubal-Kain who was manufacturing all kinds of tools from copper and iron, by forgewelding. In the beginning of the 19th century (5900 years later) shielded metal arc welding (SMAW) was introduced. From that time welding technology development has rapidly increased and we have seen a small paradigmic shift over the century. The development of steel together with the development of processes has resulted in new products and new improvements. Reports reveal how to find new solutions to unknown problems by scientific research. Other technologies have been developed in parallel such as electronics and computers, leading to the first robot in 1974. Increasing demands on productivity, safety and quality have led to more automation and thereby more complex processes. Faster, cheaper and better are the words that we hear every day. However, they are explained in more exact terms like: • • •
Cut the product development time from four years to two years. Reduce costs by 5-8% each year during the next five years. Improve the quality to World Class, ISO 9001 and EN 729-2.
The welding process itself becomes a part of a whole system, far away from what Tubal-Kain ever could have dreamt of.
Introduction Today's technology has come to a level where these goals can no longer be reached without involving the whole company. Welding technology must be a part of this development which means that existing tools and systems must
132
The welding workplace
be able to 'talk' with new systems that are to be developed. The future will be even more complex where communication, education and changes of organizations are the key issues for success. What are the alternatives? There is no doubt that if we are not successful in our development of welding production it will happen in the low cost countries and we must fully appreciate this fact. The globalization of companies is developing rapidly and purchase departments can show figures that are very hard to compete against. Our future lies in new technologies which can reach the goals that are set up. This means that we are going to meet a paradigm shift within the coming eight to ten years - it has already begun!
Paradigm shift A paradigm shift is defined as a major change in the way things are thought about, especially scientifically. Once a problem can no longer be solved in the existing paradigm, new laws and theories emerge and form a new paradigm, overthrowing the old if it is accepted. To abandon one paradigm for another is to alter the entire intellectual basis of a community whether it be scientific, political or otherwise. It represents a profound change in the thoughts, perceptions and values that form a particular vision of reality. Paradigm shifts are usually brought about by people who are young or new to a particular discipline since they are relatively free of established preconceptions. A paradigm is the consensus of the scientific community, where the professions have come to accept concrete problem solutions. The concept of paradigm has two general levels. The first is the encompassing whole, the summation of the parts. It consists of the theories, laws, rules, models, concepts and definitions that go into a generally accepted fundamental theory of science. Such a paradigm is global in its character. The other character of paradigm is that it can also be just one of these laws, theories, models, etc, that combines with others to make up a global paradigm. For instance, Galileo's theory that the earth rotated around the sun became a paradigm in itself, namely a generally accepted law in astronomy. Yet on the other hand, his theory also combined with other local paradigms in areas such as religion and politics to transform culture. In 1974ASEA (now ABB Flexible Automation) introduced the first electrical microcomputer controlled robot. Since that time development has been rapid and today we are entering the virtual manufacturing world. During the past 25 years industry has followed the development by investing in new techniques and thereby reducing manpower as well as shortening lead times quite extensively, Fig. 7.1. Facilities have become more complex and changes in products and production are now very difficult
Science and technology in the new millenium
133
Year 2000+ Present level
-~~~~~~~~~~~~~~--------------l
l
I
I I I I
rnanufacturinq plant I I I I I
1990 Robot IV
lI
! The virtual!
Robot V
1985
:I I I I I
1995
I I I I I
Off-line programming: aLA CCD camera
I
Robot II
!
CAD
I Robot I
1974
I
!
Robot III Seam searching and tracking ,---_ _+--_----' 1980
1975
!
! I I
25 years in steps of 5 years
1997
2000 10 years-~
12006 2010 l
7.1 Robot arc welding development during the past 25 years. Today we are entering the new paradigm, the virtual manufacturing plant.
because of unforeseen bottle necks. Welding automation is in this respect harder to introduce than automation in machining since welding involves heat deformation. Such a bottle neck came into existence in 1990 when a new robot installation was programmed. The complexity of the robot combined with the complex weld structures led to a total on-line programming time of approximately 500 hours! This was of course unacceptable and off-line programming was the solution. Today the down time of the robot for such programming is some 25 hours! However, off-line programming was not that simple. It required a 3D CAD model from both the design department (the weld structure), fixtures and the robot supplier. These models, at that time, were not good enough to use and therefore they had to be developed so they could fit in to the whole system, Fig. 7.2. Sharing data between different departments and databases in a global perspective will be the next challenge. Much work is going on around the world on this subject not least in the US Space Shuttle Program, as it was some 35 years ago! Industries will of course in the near future see and use some of the inventions that develop, Fig. 7.3. Over the last 25 years heavy investments have been made in robot facilities as well as in new weld structures. New investments will be even more
134
The welding workplace 3D-CAD FEM Calculation
Intergraph/EMS 3D solids (Solid edge)
3D-CAD Fixtures
Database
IEP
Processes Welding of frames QA ISO 9001 EN 729-2
Simulation Off-life programming RobCad Ver. 3.5.1 Silicon graphics
MRP IBM AS 400 MAPICS
Purchase External suppliers of robot systems B&C, IGM, ABB
TDL UNIX or PC
Ingoing parts in the product
Production process Plate and welding fabrication of frames
7.2 Information and data flow in the process of weld structure development has to be improved to meet next generation requirements.
expensive and requirements are so high that it is more or less impossible to foresee what the consequences will be unless you can see it in 'reality'. A change in one corner of the plant can show good results but in another corner it might create problems. Virtual reality simulation is a part of the new paradigm using suitable models, Fig. 7.4. To reduce arc time, high speed welding i.e rapid melt, double wire welding, time process, etc, will increase in use. Simulation of the whole process will be of great importance in order to verify the process as well as the equipment, etc. How to document the fabrication is another important issue which will be required according to standards and quality assurance documents. In the globalization process it is vital for companies that new innovations are implemented as fast as possible to other fabrication plants and used as standard. The conditions at various plants are different around the globe. Therefore it is important to simulate different alternatives. Communication between companies will be crucial for how successful the companies will be.
Science and technology in the new millenium
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Robotic welding systems in the year 2000 [2] - fit for human beings!
'Complete automation whereby all human labour is replaced by automated production'. This has long been the aim of industry. Two decades after the introduction of microprocessors, a lot has been achieved, but a more realistic view of the possibilities, and especially impossibilities has formed. We cannot deny, that although automation can reduce the human effort needed in a production process, it will not completely replace the need for a brain on the shop floor. Although desirable, and also possible in a technical sense, it has proven impractical to remove the last operator completely from a production process. The modern design and implementation of robotic welding systems therefore is not concentrating only on strictly technical matters. The system functionality must include the human factor as an integral part of the production system. In the automated production systems supplied by Kranendonk, the operator does not serve merely as an 'intelligence server' to the production system. He is in control. The automated equipment is the tool of the operator. When we consider welding processes, the following advantages of robotized processing are evident: • • • •
Robotization removes the worker from the welding area, which improves health conditions, Fig. 7.5. Repetitive strain injuries due to work in bended, kneeling or overhead working stances are avoided. The welding area can be closed off from the human workers for UV light, smoke and noise protection. Better fume extraction can be accomplished.
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These advantages were first recognized and used in series production. In shipbuilding, one-piece production is typical. Besides this, the sheer size of workpieces has stopped many yards from using robots for welding of sub-constructions and sub-sub-constructions. The conditions under which welding in ship constructions has to take place are often more difficult than in series production for part welding. The benefits of robotized welding systems are therefore much greater. As an example, welding of double hull section blocks in the shipbuilding industry can be observed. These blocks consist of a bottom panel with several vertical 'webs' placed longitudinally and laterally. This way, a number of boxes are formed, which are only open from the top. The construction requires substantial welding. The classic way of production involves a welder who has to climb into one of the boxes, carry his welding equipment along, and perform the welding inside the box. Automation of this job offers substantial benefits. Not only is the actual welding performed by a robot, but the entry of the welder is replaced by movement of the robot, complete with welding equipment, into the box, suspended from a large gantry. The 'mechanical' ergonomical aspects of this type of automation are clear. Having replaced the human labour with machine labour, the emphasis of the operator task will be the operation of a computer integrated production system. A whole line of processes is involved, ranging from the CAD design of the double hull sections, through work preparation, production control to the actual control of the equipment. Carefully implemented computer integration in this part adds to the user-friendliness of the system. A second, related example is the cutting of profiles carried out in many shipyards. Today, productivity and efficiency of the profile production is a very important factor. This has caused shipyards to move away from conventional autogenous cutting to plasma cutting technologies. The latest dry oxygen plasma cutting processes are hardly fit for manual cutting for the following reasons: • • •
The weight of the torch makes manual handling difficult The cutting process produces much smoke, noise and No, gases Like welding, the process emits strong UV radiation.
The dry oxygen cutting process offers faster processing, and very good product quality but can only be used in an automated environment. In shipbuilding, the manual cutting shop is replaced by an automated robot profile cutting line. Instead of worsening the environment for the cutting operator, it has been improved significantly on the following points: •
The torch is handled by the robot i.e. the operator is removed from the process yet remains in full control.
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The welding workplace
Programming of the robot is automatic, off-line, via a CAD/CAM connection. Enclosing the cutting area in a soundproof cabin offers excellent noise shielding, not only for the operator, but also for the entire environment. The process can be monitored through windows in the enclosing cabin. Special coating blocks the UV radiation. Scrap can be disposed of centrally. The cabin has efficient fume extraction with centralized filter units for dust and smoke. Observation cameras can be installed to optimise the operator's view on the cutting process.
Computer integrated systems are not yet commonplace in the shipbuilding industry. In many shipyards, the hull prefabrication processes are still the work of real craftsmen. Implementation of computer integrated technology must therefore be done in a careful way. Even though the high level of automation is only achieved through computer integration, the computer systems themselves should not be too much in the foreground. The former steel workers usually have no desire to be trained as computer technicians. It is important to use the capabilities of modern computer technology to create an operator interface that makes operating procedures as simple as possible. As an example, the production data required to control a profile cutting robot system does not look very appealing, see Fig. 7.6. The use of a graphical user interface offers the possibility to directly show the resulting shape of the cut as defined within the control system. Modern operating systems also allow more than one task to run from one computer station. Several tasks can run in separate windows. This eliminates the need for several separate terminals or control stations. S,A111 P,A1738-R,HP180X10,3120,3,TACKWELD ONLY B,50,100,950,100,70 B,900,100,1800,100,50 B,1750,100,2650,100,30 B,2600,100,3100,100,10 e,l 0,3 M,B-P4-L, 50, 60 I,1000, B-RATH, 100, 50 I,2120, B-RATH, 100, 50 M,B-P4-R,50,60 7.6 Example of production datafile (courtesy of Kranendonk Automation BV).
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Computer integrated robot welding and cutting cells allow for further integration of work preparation processes, see Fig. 7.7. This reduces the number of human actions required to operate the system. It offers a local work preparation station (LWP) for each one of the production lines in the system, and one central work preparation system (CWP) integrating the production control and logistics control of the various lines. This distributed method of production automation offers both a high level of automation and the flexibility required in a production environment. The high level of automation allows the hull fabrication to be performed by very few people, having control jobs rather than menial work. On each level of the control system, the system handles a relevant part of the production data. In the central work preparation office (CWP) most of the work concerns planning activities: • • •
Selection of which jobs are to be executed in the next shift or day. Transfer of the production data from the yard's host system. Releasing the data for production.
In the local work preparation offices, production data for each of the production lines can be modified. For instance, a 'rush job' can be manually entered and production of the job started. On the shop floor, production is monitored. The welding expert on the shop floor has access to the database of process parameters that the automation system uses to assign process parameters for the welding system. This implies that in the design and work preparation phase of the production process, welds are described by their physical specifications (such as throat height, etc) and that the translation of the specifications into actual process parameters is automatically done on the shop floor, where direct feedback (through the welding engineer's observation or through automated process monitoring equipment) is possible. The human insight is in this way used in combination with the automated data system, which allows even less straightforward welding jobs to be carried out by such an automated system. A final but important aspect of ergonomy in automated production systems is not built into the system as such, i.e. the way in which the new system and new operational procedures are introduced and implemented in the end user's plant. It is not only important to train the actual operators in the operation of the equipment and software, but also to supply these personnel with sufficient background intormation to create an understanding of what is going on within the system. In addition, experience has shown that it pays to train people who are not directly involved with the new system, but whose jobs will be affected by it. Creating understanding helps tremendously to integrate the new production system into the existing production.
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The difference in automation per se, and the successful implementation of automated production systems is that in the latter, the place that humans take is carefully considered. Then, not only does automation work but the system is a place fit for humans to work in.
References 1 Hans Brostrom, Volvo Wheel Loaders AB, Sweden, IIW Document XII-1526-98. 2 Kranendonk Automation Systems AB, Netherlands.