| 1. |
- Ahlberg, Erik, et al.
(författare)
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"Vi klimatforskare stödjer Greta och skolungdomarna"
- 2019
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Ingår i: Dagens nyheter (DN debatt). - 1101-2447.
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- DN DEBATT 15/3. Sedan industrialiseringens början har vi använt omkring fyra femtedelar av den mängd fossilt kol som får förbrännas för att vi ska klara Parisavtalet. Vi har bara en femtedel kvar och det är bråttom att kraftigt reducera utsläppen. Det har Greta Thunberg och de strejkande ungdomarna förstått. Därför stödjer vi deras krav, skriver 270 klimatforskare.
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| 2. |
- Ask, Urban, 1956, et al.
(författare)
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IT Governance in the light of Paradox - A Social System Theory Perspective
- 2006
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Ingår i: The 40th Hawaii International Conference on System Sciences, 2007.
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Konferensbidrag (refereegranskat)abstract
- This paper uses Niclas Luhmann's concepts of paradox and deparadoxization as a starting point for looking at IT governance within large, Swedish organizations. All in all a total of 25 organizations within both the public and private sector have been investigated through interviews with the companies Chief Information Officers. The results are presented in relation to a number of areas within the study that could be identified as dichotomies, or areas where the respondents had to deal with conflicting logics. The results are discussed in general terms in relation to IT governance practice as well as the potential value of applying Luhmann's theory of social systems to the study of IT governance
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| 3. |
- Björnsson, Andreas, 1981-, et al.
(författare)
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Automated Composite Manufacturing Using Off-the-shelf Automation Equipment – A Case from the Space Industry
- 2014
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Ingår i: Proceedings of the 16th European Conference on Composite Materials, 22nd-26th June 2014, Seville, Spain. - 9788461697984
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Konferensbidrag (refereegranskat)abstract
- A novel approach to the manufacturing of composite products using off-the-shelf automation equipment is explored in this article. A manufacturing concept for a specific product is developed and analyzed, from a technical perspective, in order to find areas where off-the-shelf automation equipment can be used. The article also highlights areas where case-specific solutions need to be developed. In this particular case, off-the-shelf automation equipment can be used for most of the tasks that the manufacturing system needs to perform. The most challenging process is identified as the application of adhesive. The manufacturing concept described in the article shows that it is possible to build a system for the manufacturing of composite components using a high degree of off-the-shelf automation equipment.
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| 4. |
- Björnsson, Andreas
(författare)
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Automated layup and forming of prepreg laminates
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Composite materials like carbon fiber-reinforced polymers (CFRPs) present highly appealing material properties, as they can combine high strength with low weight. In aerospace applications, these properties help to realize lightweight designs that can reduce fuel consumption. Within the aerospace industry, the use of these types of materials has increased drastically with the introduction of a new generation of commercial aircraft. This increased use of CFRP drives a need to develop more rational manufacturing methods.For aerospace applications, CFRP products are commonly manufactured from a material called prepreg, which consists of carbon fibers impregnated with uncured polymer resin. There are two dominant manufacturing technologies for automated manufacturing using prepreg, automated tape layup and automated fiber placement. These two technologies are not suitable for all types of products, either due to technical limitations or a combination of high investment costs and low productivity. Automation alternatives to the two dominant technologies have been attempted, but have so far had limited impact. Due to the lack of automation alternatives, manual manufacturing methods are commonly employed for the manufacturing of complex-shaped products in low to medium manufacturing volumes.The research presented in this thesis aims to explore how automated manufacturing systems for the manufacturing of complex CFRP products made from prepreg can be designed so that they meet the needs and requirements of the aerospace industry, and are suitable for low to medium production volumes. In order to explore the area, a demonstrator-centered research approach has been employed. A number of demonstrators, in the form of automated manufacturing cells, have been designed and tested with industrial and research partners. The demonstrators have been used to identify key methods and technologies that enable this type of manufacturing, and to analyze some of these methods and technologies in detail. The demonstrators have also been used to map challenges that affect the development of enabling methods and technologies.Automated manufacturing of products with complex shapes can be simplified by dividing the process into two steps. Thin layers of prepreg are laid up on top of each other to form flat laminates that are formed to the desired shape in subsequent forming operations. The key methods and technologies required to automate such a system are methods and technologies for automated prepreg layup, the automated removal of backing paper and the forming of complex shapes. The main challenges are the low structural rigidity and tacky nature of prepreg materials, the extensive quality requirements in the aerospace industry and the need for the systems to handle a wide array of prepreg shapes.The demonstrators show that it is possible to automate the manufacturing of complexshaped products using automated layup and forming of prepreg laminates. Tests using the demonstrators indicate that it is possible to meet the quality requirements that apply to manual manufacturing of similar products.
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| 5. |
- Björnsson, Andreas, 1981-, et al.
(författare)
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Automated material handling in composite manufacturing using pick-and-place systems - a review
- 2018
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Ingår i: Robotics and Computer-Integrated Manufacturing. - : Elsevier BV. - 0736-5845 .- 1879-2537. ; 51, s. 222-229
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Tidskriftsartikel (refereegranskat)abstract
- With increasing use of fiber reinforced polymer composites follows a natural pursuit for more rational and effective manufacturing. Robotic pick-and-place systems can be used to automate handling of a multitude of materials used in the manufacturing of composite parts. There are systems developed for automated layup of prepreg, dry fibers and thermoplastic blanks as well as to handle auxiliary materials used in manufacturing. The aim of this paper is to highlight the challenges associated with automated handling of these materials and to analyze the main design principles that have been employed for pick-and-place systems in terms of handling strategy, reconfigurability, gripping technology and distribution of gripping points etc. The review shows that it is hard to find generic solutions for automated material handling due to the great variety in material properties. Few cases of industrial applications in full-scale manufacturing could be identified.
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| 6. |
- Björnsson, Andreas, 1981-, et al.
(författare)
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Automated Removal of Prepreg Backing Paper - A Sticky Problem
- 2013
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Ingår i: Proceedings of the SAE 2013, Aerotech Congress and Exhibition, 24th-26th September 2013, Montreal,Canada. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International.
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Konferensbidrag (refereegranskat)abstract
- Automated solutions for manufacturing composite products based on prepreg often imply Automatic Fiber Placement or Automatic Tape Laying. These systems are generally associated with huge investments. For certain manufacturing applications it is interesting to investigate alternatives to find simpler and less costly automation. One example of an automated system could be the use of a standard industrial robot to pick single prepreg plies from an automated cutting machine and stack them to form a plane laminate. This paper is based on a case illustrating a product from the aircraft manufacturing industry. The case will demonstrate a pick and place concept on a general level and illustrate challenges that must be solved. The challenge selected to be the main focus for this paper is an automated process for backing paper removal. A literature review of different gripping technologies reveals several interesting technologies, and the most promising are tested for backing paper removal. The tests show that an automated removal process can be designed by using standard vacuum grippers in combination with mechanical clamping grippers. In order to lift the backing paper with a vacuum gripper an initial separation between the backing paper and prepreg is needed. This separation is most easily mechanically induced by bending the material. The proposed solution for automatic backing paper removal can be integrated in a manufacturing cell for manufacturing of the studied product.
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| 7. |
- Björnsson, Andreas, 1981-, et al.
(författare)
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Automation of composite manufacturing using off-the-shelf solutions; three cases from the aerospace industry
- 2015
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Ingår i: ICCM International Conferences on Composite Materials. - : International Committee on Composite Materials.
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Konferensbidrag (refereegranskat)abstract
- With an increased use of composite materials follows a need for rational, cost-efficient manufacturing processes. This paper explores how off-the-shelf solutions, developed for other purposes than composite manufacturing, can be used to build systems for automated composite manufacturing. Three demonstrators, each of them dealing with a specific type of material and all of them representing different manufacturing technologies for automated composite manufacturing, are presented and analyzed to find aspects that affect the ability to use off-the-shelf solutions. The three demonstrators target low to medium manufacturing volumes of complex products and they have been developed in collaboration with industrial partners within the aerospace industry. The conclusions drawn from the development of the demonstrators are that it is technically feasible to use off-the-shelf solutions in the three cases while adhering to the high quality standards of the industry. Furthermore three groups of aspects, quality aspects, product aspects and system aspects, which affect the ability to use off-the-shelf solutions for automated composite manufacturing, are identified.
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| 8. |
- Björnsson, Andreas, 1981-, et al.
(författare)
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Composite Manufacturing : How Improvement Work Might Lead to Renewed Product Validation
- 2012
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Ingår i: Proceedings of the 5th International Swedish Production Symposium. - 9789175197524 ; , s. 505-513
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Konferensbidrag (refereegranskat)abstract
- High-performance polymer composites are mainly used in applications where the benefits of high strength and low weight justify the high material and manufacturing costs. Many of these applications are found today in the aerospace, space and defense industries. Most of today’s commonly used manufacturing methods within this area are highly labor intensive. Furthermore, the quality requirements from the customers require a high level of process control. The purpose of this paper is to explore how changes that are introduced in order to improve productivity in a manufacturing system are managed, particularly with regard to who takes the decision to implement a change and how a change is validated. The study is based on qualitative interviews performed at several companies that manufacture composite components for the aerospace, space and defense sectors. The findings show that the responsibility for deciding to implement a change and the need for validating it are based on many diverse and interconnected factors. Therefore, it is difficult to construct guidelines for early assessment of the scope and cost of a proposed change. Hence each individual change request must be evaluated on its own. The study also shows that the validation process can be adapted to a level that is based on the type of change. In addition, it highlights that control over process parameters in manufacturing is essential.
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| 9. |
- Björnsson, Andreas
(författare)
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Enabling Automation of Composite Manufacturing through the Use of Off-The-Shelf Solutions
- 2014
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Composite materials offer an appealing combination of low weight and high strength that is especially sought after in high-performance applications. The use of composite materials has and is continuing to increase, and the use of the material has been shown to provide substantial weight savings in for example aircraft design. With an increased use of composite materials follows an increased demand for cost-efficient manufacturing methods.Composite products are in many cases manufactured either by manual operations or by the use of complex automated solutions associated with high investment costs. The objective for this research is to explore an approach to develop automated composite manufacturing based on commercially available off-the-shelf solutions as an alternative to the existing automated solutions for composite manufacturing.The research, which was carried out in collaboration with industrial partners within the aerospace sector, is based on a demonstrator-centered research approach. Three conceptual demonstrators, focusing on three different manufacturing methods and a number of physical demonstrators, are used to show that off-the-shelf solutions can be used for automated manufacturing of composite products.Two aspects that affect if it is possible to use off-the-shelf solutions for automated composite manufacturing are the rigorous quality standards used by the aerospace industry and the great variety in product properties and material properties that is associated with composite manufacturing.The advantages in using off-the-shelf solutions has shown to be that the solutions generally are associated with low investments and that published information about the solutions, and the solutions themselves, is generally available for evaluation and testing. When working with the demonstrators it has been shown to be useful to break down a manufacturing system into basic tasks and consider off-the-shelf solutions for each particular task. This approach facilitates the search for a suitable off-the-shelf solution to solve a particular task. However, each of the separate tasks can affect other areas of the manufacturing system, and an overall systems perspective is required to find solutions that are compatible with the entire manufacturing system.
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| 10. |
- Björnsson, Andreas, et al.
(författare)
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Getting to grips with automated prepreg handling
- 2017
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Ingår i: Production Engineering. - : Springer Science and Business Media LLC. - 0944-6524 .- 1863-7353. ; 11:4-5, s. 445-453
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Tidskriftsartikel (refereegranskat)abstract
- Automated manufacturing of composite parts based on prepreg material is receiving increased interest with the rising use of composite materials for high-performance applications. The two main automation alternatives for prepreg layup, automated tape layup and fiber placement, are not cost-effective for all types of products, and manual labor is common for the manufacturing of complex parts in low manufacturing volumes. Alternatives to the two dominant automation solutions have been pursued, but so far these have had a limited impact in industrial applications. This paper presents four different solutions for automated layup of prepreg plies to flat laminates that can be formed in a subsequent forming process, which decrease the system complexity. The solutions target products where the layup of flat laminates today is done manually due to technical limitations or cost considerations. The layup solutions must manage challenges caused by material properties such as low material rigidity and tack, and be able to handle a high number of ply shapes. All four solutions are designed for prepreg that is covered with a stiff backing paper. The aim of the paper is to analyze and compare the four solutions. It can be concluded that the most versatile solution is a dual-arm robot equipped with simple end effectors. The dual-arm solution presents a possibility to control the pick-up and lay-down motions that make peeling motions possible, which is advantageous when picking material that has tacked to the pickup surface.
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