| 1. |
- Bayani, Mohsen, 1981, et al.
(author)
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Geometric robustness and dynamic response management by structural topometry optimisation to reduce the risk for squeak and rattle
- 2022
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In: Design Science. - : Cambridge University Press (CUP). - 2053-4701. ; 8
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Journal article (peer-reviewed)abstract
- Historically, squeak and rattle (S&R) sounds have been among the top quality problems and a major contributor to the warranty costs in passenger cars. Geometric variation is among the main causes of S&R. Though, geometric variation analysis and robust design techniques have been passively involved in the open-loop design activities in the predesign-freeze phases of car development. Despite the successful application of topometry optimisation to enhance attributes such as weight, durability, noise and vibration and crashworthiness in passenger cars, the implementation of closed-loop structural optimisation in the robust design context to reduce the risk for S&R has been limited. In this respect, the main obstacles have been the demanding computational resources and the absence of quantified S&R risk evaluation methods. In this work, a topometry optimisation approach is proposed to involve the geometric variation analysis in an attribute balancing problem together with the dynamic response of the system. The proposed method was used to identify the potential areas of a door component that needed structural reinforcement. The main objective was to enhance the design robustness to minimise the risk for S&R by improving the system response to static geometrical uncertainties and dynamic excitation.
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| 2. |
- Bayani, Mohsen, 1981, et al.
(author)
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Squeak and rattle prevention by geometric variation management using a two-stage evolutionary optimisation approach
- 2020
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In: ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE). ; 2B-2020
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Conference paper (peer-reviewed)abstract
- Squeak and rattle are annoying sounds that often are regarded as the indicators for defects and quality issues by the automotive customers. Among the major causes for the generation of squeak and rattle sounds, geometric variation or tolerance stack-up is a key contributor. In the assembly process, the dimensional variation in critical interfaces for generating squeak and rattle events can be magnified due to tolerance stackup. One provision to manage the tolerance stack-up in these critical interfaces is to optimise the location of connectors between parts in an assembly. Hence, the focus of this work is to prevent squeak and rattle by introducing a geometric variation management approach to be used in the design phase in the automotive industry. The objective is to identify connection configurations that result in minimum variation and deviation in selected measure points from the critical interfaces for squeak and rattle. In this study, a two-stage evolutionary optimisation scheme, based on the genetic algorithm employing the elitism pool, is introduced to fine-tune the connectors’ configuration in an assembly. The objective function was defined as the variation and the deviation in the normal direction and the squeak plane. In the first stage, the location of one-dimensional connectors was found by minimising the objective function in the rattle direction. In the second stage, the best combination of some of the connectors from the first stage was found to define planar fasteners to optimise the objective function both in the rattle direction and the squeak plane. It was shown that by using the proposed two-stage optimisation scheme, the variation and deviation results in critical interfaces for squeak and rattle improved compared to the baseline results.
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| 3. |
- Bayani, Mohsen, 1981, et al.
(author)
-
Squeak and rattle prevention by geometric variation management using a two-stage evolutionary optimization approach
- 2022
-
In: Journal of Computing and Information Science in Engineering. - : ASME International. - 1530-9827 .- 1944-7078. ; 22:1
-
Journal article (peer-reviewed)abstract
- Squeak and rattle are annoying sounds that are often regarded as failure indicators by car users. Geometric variation is a key contributor to the generation of squeak and rattle sounds. Optimization of the connection configuration in assemblies can be a provision to minimize this risk. However, the optimization process for large assemblies can be computationally expensive. The focus of this work is to propose a two-stage evolutionary optimization scheme to find the fittest connection configurations that minimize the risk for squeak and rattle. This was done by defining the objective functions as the measured variation and deviation in the rattle direction and the squeak plane. In the first stage, the location of the fasteners primarily contributing to the rattle direction measures is identified. In the second stage, fasteners primarily contributing to the squeak plane measures are added to the fittest configuration from phase one. It was assumed that the fasteners from the squeak group plane have a lower-order effect on the rattle direction measures, compared to the fasteners from the rattle direction group. This assumption was falsified for a set of simplified geometries. Also, a new uniform space filler algorithm was introduced to efficiently generate an inclusive and feasible starting population for the optimization process by incorporating the problem constraints in the algorithm. For two industrial cases, it was shown that by using the proposed two-stage optimization scheme, the variation and deviation measures in critical interfaces for squeak and rattle improved compared to the baseline results.
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| 4. |
- Bohlin, Robert, 1972, et al.
(author)
-
Data Flow and Communication Framework Supporting Digital Twin for Geometry Assurance
- 2018
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In: ASME 2017 International Mechanical Engineering Congress and Exposition. ; 2
-
Conference paper (peer-reviewed)abstract
- Faster optimization algorithms, increased computer power and amount of available data, can leverage the area of simulation towards real-time control and optimization of products and production systems. This concept — often referred to as Digital Twin — enables real-time geometry assurance and allows moving from mass production to more individualized production. To master the challenges of a Digital Twin for Geometry Assurance the project Smart Assembly 4.0 gathers Swedish researchers within product development, automation, virtual manufacturing, control theory, data analysis and machine learning. The vision of Smart Assembly 4.0 is the autonomous, self-optimizing robotized assembly factory, which maximizes quality and throughput, while keeping flexibility and reducing cost, by a sensing, thinking and acting strategy. The concept is based on active part matching and self-adjusting equipment which improves geometric quality without tightening the tolerances of incoming parts. The goal is to assemble products with higher quality than the incoming parts. The concept utilizes information about individual parts to be joined (sensing), selects the best combination of parts (thinking) and adjust locator positions, clamps, weld/rivet positions and sequences (acting). The project is ongoing, and this paper specifies and highlights the infrastructure, components and data flows necessary in the Digital Twin in order to realize Smart Assembly 4.0. The framework is generic, but the paper focuses on a spot weld station where two robots join two sheet metal parts in an adjustable fixture.
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| 5. |
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| 6. |
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| 7. |
- Carlson, Johan, 1972, et al.
(author)
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Non-nominal path planning for robust robotic assembly
- 2013
-
In: Journal of Manufacturing Systems. - : Elsevier BV. - 0278-6125. ; 32:3, s. 429-435
-
Journal article (peer-reviewed)abstract
- In manufacturing and assembly processes it is important, in terms of time and money, to verify the feasi-bility of the operations at the design stage and at early production planning. To achieve that, verificationin a virtual environment is often performed by using methods such as path planning and simulation ofdimensional variation. Lately, these areas have gained interest both in industry and academia, however,they are almost always treated as separate activities, leading to unnecessary tight tolerances and on-lineadjustments.To resolve this, we present a novel procedure based on the interaction between path planning tech-niques and variation simulation. This combined tool is able to compute robust assembly paths forindustrial robots, i.e. paths less sensitive to the geometrical variation existing in the robot links, in itscontrol system, and in the environment. This may lead to increased productivity and may limit errorsources. The main idea to improve robustness is to enable robots to avoid motions in areas with highvariation, preferring instead low variation zones. The method is able to deal with the different geometricalvariation due to the different robot kinematic configurations. Computing variation might be a computa-tionally expensive task or variation data might be unavailable in the entire state space, therefore threedifferent ways to estimate variation are also proposed and compared. An industrial test case from theautomotive industry is successfully studied and the results are presented.
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| 8. |
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| 9. |
- Dagman, Andreas, 1976, et al.
(author)
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Form division in automobile design - linking design and manufacturability
- 2006
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In: Design 2006 9th International Design Conference, May 15-18, 2006, Dubrovnik, Croatia, Editor Marjanovic´, D. - 9536313790 ; 1, s. 495-502
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Conference paper (peer-reviewed)
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| 10. |
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| 11. |
- Edholm, Peter, 1974, et al.
(author)
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Geometrical Coupling Analysis to Reduce Complete Assembly Line Complexity
- 2012
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In: Proceedings of the ASME 2012 International Mechanical Engineering Congress & Exposition, IMECE2012, November 9-15, 2012, Houston, Texas, USA. - 9780791845196 ; 3:PARTS A, B, AND C, s. 89-96
-
Conference paper (peer-reviewed)abstract
- Modern assembly lines for mass production need to fulfill several important criteria. One of them is to produce products with high geometrical quality (small geometric variation). For sheet metal assemblies, focused on in this paper, it is a very complex process to achieve good geometrical quality due to the large number of assembly steps and the geometrical variation (tolerances) of the incoming parts. One “golden rule” for sheet metal assembly lines is to always reuse fixturing points (locators) throughout the whole assembly line to minimize the geometrical variation and also the complexity of root cause analysis.A new method to measure the complexity in an assembly line has been developed and also implemented in a commercial software for Computer Aided Tolerancing. This new tool not only demonstrates the “golden rule” but could also be used to ensure minimum geometrical complexity in assembly lines to ensure controlled production and high quality products.
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| 12. |
- Edholm, Peter, 1974, et al.
(author)
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Geometry robustness evaluation for common parts in platform architecture
- 2011
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In: International Journal of Shape Modeling. - 0218-6543. ; 16:1&2, s. 129-150
-
Journal article (peer-reviewed)abstract
- In this paper, a platform geometrical sensitivity value for a part has been defined. Calculation and simulation methods have been defined and tested to be used in industrial “real-life” environments. Present calculation and simulation methods for assembly analysis in a single product development have been used as a basis. These methods have been further developed and adapted to suit product family development, or platforms. The assembly geometrical sensitivity value can be used to predict the effect of tolerance stacking without having data of tolerance sizes available. Using sensitivity calculation in each assembly step gives an indication of the risk of functional failure and non-fulfilled specifications due to tolerance stacking. The platform geometrical sensitivity value could be used for optimization of a part or an assembly, by means of geometric variation, not only for one product environment but also for a complete product family simultaneously. This decreases the risk of sub-optimization of part location and assembly concepts. Using the platform geometrical sensitivity value, the effect of tolerance stacking could be predicted for all assemblies conceptually and the result can be used to dimension specific part tolerances. All equations and mathematical connections are described in detail in the paper but, due to the mathematical complexity of 3D modeling, the calculations have been performed in a geometry simulation tool. Further research needs to be done to establish a proper working procedure using platform geometrical sensitivity value.
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| 13. |
- Edholm, Peter, 1974, et al.
(author)
-
Geometry robustness evaluation for common parts in platform architecture
- 2010
-
In: Proceedings of the 8th International Symposium on Tools and Methods of Competitive Engineering, TMCE 2010. April 12–16, 2010, Ancona, Italy. - 9789051550603 ; 2, s. 1003-1012
-
Conference paper (peer-reviewed)abstract
- In this paper, a platform geometry goodness value for a part has been defined. Calculation and simulation methods have been defined and tested to be used in industrial "real-life" environments. Present calculation and simulation methods for assembly analysis in a single product development have been used as a basis. These methods have been further developed and adapted to suit product family development, or platforms. The platform geometry robustness value could be used for optimization of a part or an assembly, by means of geometric variation, not only for one product environment but also for a complete product family simultaneously. This decreases the risk of suboptimization of part location and assembly concepts. All equations and mathematical connections are described in detail in the paper but, due to the mathematical complexity of 3D modelling, the calculations have been performed in a geometry simulation tool. The proposed theories are based on previous work by Söderberg [7] presented mainly in section 2. The new contribution from this paper is mainly presented in sections 4.2 and 5.
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| 14. |
- Edholm, Peter, 1974, et al.
(author)
-
Minimizing Geometric Variation in Multiusage Assembly Line by Geometrical Decoupling
- 2011
-
In: ASME 2011 International Mechanical Engineering Congress and Exposition, IMECE2011, November 11-17, 2011, Denver, Colorado, USA. - 9780791854891 ; 3, s. 63-71
-
Conference paper (peer-reviewed)abstract
- Geometrical part robustness is today used as an engineering criterion in many manufacturing companies. The goal is to minimize the effect of geometrical variation by optimizing the locating schemes for the parts. Several methods and tools are today present to support geometrical robustness optimization for parts but also for assemblies. In this paper focus is on geometrical decoupling, which is one parameter of geometrical robustness, of the different locating strategies in a complete assembly line. A goodness value is proposed that describe the level of geometrical couplings in a complete assembly line together with the part robustness value. By calculating this goodness value it is possible to predict the geometrical sensitivity of a complete assembly line as well as predicting the risk of geometrical variation on the final product. To illustrate the definition of this goodness value, and also the purpose of calculating it, a case study is used where a part of a sheet metal assembly line is described. Several different scenarios (assembly concepts) are applied to clarify the meaning and to validate this definition of the goodness value. The case study shows that the goodness value gives a good indication of the level of geometrical couplings within the assembly line and that this value could be used to evaluate different assembly concepts, with their locating concepts, against each other. The goal is to have a more robust and also geometrically decoupled assembly line which the root cause analysis in production and also optimizes the geometrical quality minimizing the effect of geometrical variation of the final product from the plant.
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| 15. |
- Forslund, Anders, 1982, et al.
(author)
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Minimizing Weld Variation Effects Using Permutation Genetic Algorithms and Virtual Locator Trimming
- 2018
-
In: Proceedings of the ASME 2017 International Mechanical Engineering Congress and Exposition. ; 2
-
Conference paper (peer-reviewed)abstract
- The mass production paradigm strives for uniformity, and for assembly operations to be identical for each individual product. To accommodate geometric variation between individual parts in such a process, tolerances are introduced into the design. However, for certain assembly operations this method can yield suboptimal quality. For instance, in welded assemblies, geometric variation in ingoing parts can significantly impair quality. When parts misalign in interfaces, excessive clamping force must be applied, resulting in additional residual stresses in the welded assemblies. This problem may not always be cost-effective to address simply by tightening tolerances. Therefore, under new paradigm of mass customization, the manufacturing approach can be adapted on an individual level. Since parts in welded assemblies are not easily disassembled and reused, interchangeability is not a relevant concern. This recognition means that each welded assembly can be adapted individually for the specific idiosyncrasies of ingoing parts. This paper focuses on two specific mass customization techniques; permutation genetic algorithms to assemble nominally identical parts, and virtual locator trimming. Based on these techniques, a six-step method is proposed, aimed at minimizing thing effects of geometric variation. The six steps are nominal reference point optimization, permutation GA configuration optimization, virtual locator trimming, clamping, welding simulation, and fatigue life evaluation. A case study is presented which focuses on one specific product; the turbine rear structure of a commercial turbofan engine. Using this simulation approach, the effects of using permutation genetic algorithms and virtual locator trimming to reduce variation are evaluated. The results show that both methods significantly reduce seam variation. However, virtual locator trimming is far more effective in the test case presented, since it virtually eliminates seam variation. This can be attributed to the orthogonality in fixturing. Seam variation is linked to weldability, which in turn has significant impact on estimated fatigue life. These results underscore the potential of virtual trimming and genetic algorithms in manufacturing, as a means both to reduce cost and increase functional quality.
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| 16. |
- Forslund, Anders, 1982, et al.
(author)
-
Minimizing weld variation effects using permutation genetic algorithms and virtual locator trimming
- 2018
-
In: Journal of Computing and Information Science in Engineering. - : ASME International. - 1530-9827 .- 1944-7078. ; 18:4
-
Journal article (peer-reviewed)abstract
- The mass production paradigm strives for uniformity, and for assembly operations to be identical for each individual product. To accommodate geometric variation between individual parts, tolerances are introduced into the design. However, this method can yield suboptimal quality. In welded assemblies, geometric variation in ingoing parts can significantly impair quality. When parts misalign in interfaces, excessive clamping force must be applied, resulting in additional residual stresses in the welded assemblies. This problem may not always be cost-effective to address simply by tightening tolerances. Therefore, under new paradigm of mass customization, the manufacturing approach can be adapted on an individual level. This paper focuses on two specific mass customization techniques: permutation genetic algorithms (GA) and virtual locator trimming. Based on these techniques, a six-step method is proposed, aimed at minimizing the effects of geometric variation. The six steps are nominal reference point optimization, permutation GA configuration optimization, virtual locator trimming, clamping, welding simulation, and fatigue life evaluation. A case study is presented, which focuses on the selective assembly process of a turbine rear structure of a commercial turbofan engine, where 11 nominally identical parts are welded into a ring. Using this simulation approach, the effects of using permutation GAs and virtual locator trimming to reduce variation are evaluated. The results show that both methods significantly reduce seam variation. However, virtual locator trimming is far more effective in the test case presented, since it virtually eliminates seam variation. These results underscore the potential of virtual trimming and GAs in manufacturing, as a means both to reduce cost and increase functional quality.
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| 17. |
- GUNNARSDÓTTIR, SOFFÍA ARNÞRÚÐUR, 1987, et al.
(author)
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Towards Simulation of Geometrical Effects of Laser Tempering of Boron Steel before Self-Pierce Riveting
- 2016
-
In: Procedia CIRP. - : Elsevier BV. - 2212-8271. ; 44, s. 304-309
-
Conference paper (peer-reviewed)abstract
- The automotive industry is continuously developing and finding new ways to respond to the incremental demands of higher safety standards and lower environmental impact. As an answer to weight reduction of vehicles, the combination of boron steel and composite material is being developed along with their joining process, self-pierce riveting. Boron steel is an ultra-high strength material that needs to be locally softened before the joining process. However, the joining process deforms the part. This paper investigates factors affecting the geometrical deformation during the tempering process and lists important phenomena that need to be included when simulating the tempering process.
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| 18. |
- Jareteg, Cornelia, 1986, et al.
(author)
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Geometry Assurance Integrating Process Variation with Simulation of Spring-in for Composite Parts and Assemblies
- 2014
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In: Proc. of ASME 2014 International Mechanical Engineering Congress & Exposition. - 9780791846438 ; 2A
-
Conference paper (peer-reviewed)abstract
- Geometrical variation and deviation in all manufacturing processes affect quality of the final product. Therefore geometry assurance is an important tool in the design phase of a new product. In the automotive and aviation industries where the use of composite parts is increasing drastically, new tools within variation simulations are needed. Composite parts tend to deviate more from nominal specification compared to metal parts. Methods to simulate the manufacturing process of composites have been developed before. In this paper we present how to combine the process variation simulation of composites with traditional variation simulations. The proposed method is demonstrated on a real complex subassembly, representing part of an aircraft wing-box. Since traditional variation simulation methods are not able to capture the spring-in and the special deviation behavior of composites,the proposed method adds a new feature and reliability to the geometry assurance process of composite assemblies.
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| 19. |
- Jareteg, Cornelia, 1986, et al.
(author)
-
Geometry Assurance Integrating Process Variation with Simulation of Spring-In for Composite Parts and Assemblies
- 2016
-
In: Journal of Computing and Information Science in Engineering. - : ASME International. - 1530-9827 .- 1944-7078. ; 16:3
-
Journal article (peer-reviewed)abstract
- Copyright © 2016 by ASME.Geometrical variation and deviation in all the manufacturing processes affect the quality of the final product. Therefore, geometry assurance is an important tool in the design phase of a new product. In the automotive and aviation industries where the use of composite parts is increasing drastically, new tools within variation simulations are needed. Composite parts tend to deviate more from nominal specification compared to metal parts. Methods to simulate the manufacturing process of composites have been developed before. In this paper, we present how to combine the process variation simulation of composites with traditional variation simulations. The proposed method is demonstrated on a real complex subassembly, representing part of an aircraft wing-box. Since traditional variation simulation methods are not able to capture the spring-in and the special deviation behavior of composites, the proposed method adds a new feature and reliability to the geometry assurance process of composite assemblies.
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| 20. |
- Jareteg, Cornelia, 1986, et al.
(author)
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Variation simulation for composite parts and assemblies including variation in fiber orientation and thickness
- 2014
-
In: Procedia CIRP CATS 2014. 5th CATS 2014 - CIRP Conference on Assembly Technologies and Systems. - : Elsevier BV. - 2212-8271. ; 23, s. 235-240
-
Conference paper (peer-reviewed)abstract
- All manufacturing processes are afflicted by geometrical variation, which can lead to defect products. A simulation tool for geometry assurance analysis is therefore important in the design process. The use of composites has recently increased drastically, but there is still a lack of understanding about the effects of variation in such parts. A method for predicting variation in subassemblies, including variation in fiber orientation and ply thickness for composites is presented. The approach is demonstrated on an industrial case and finite element analysis is used to calculate the deformation. In particular, contribution from variation in material properties to the variation in critical points is analyzed. The results indicate that material uncertainties have a small impact on the geometric variation for the test case.
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| 21. |
- Johansson, Björn, 1975, et al.
(author)
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SUSTAINABLE PRODUCTION RESEARCH: AWARENESS, MEASURES AND DEVELOPMENT
- 2012
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In: International Journal of Sustainable Development. - 1923-6662. ; 4:11, s. 95-104
-
Journal article (peer-reviewed)abstract
- This paper takes its standpoint in thehypothesis that awareness of sustainability is the keyto create sustainable products, and that this awarenessbegins already at research level. It describes thedevelopment and follow-up of a method forincreasing sustainability awareness in sustainableproduction research. Several activities were carriedout to increase the awareness. Firstly) workshopswith researchers and industry on sustainability.Secondly) development of measures based onliterature and interviews with researchers. Thirdly)monitoring of awareness through concept maps.Progress was evaluated by comparing the awarenessof the population when the project started in 2010,and then again in 2011. The results show that theparticipants had shifted their view from primaryemphasizing technology towards a more balancedview of sustainability where social aspects were moreoften taken into consideration. According to theconcept maps methodology, sustainability awarenessin the population increased with 25%.
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| 22. |
- Kero, Timo, 1973, et al.
(author)
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A Method for Improving Dental Crown Fit-Increasing the Robustness
- 2010
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In: International Journal of Medicine and Medical Sciences. - 2073-2686. ; 1:3, s. 185-192
-
Journal article (peer-reviewed)abstract
- The introduction of mass-customization has enablednew ways to treat patients within medicine. However, theintroduction of industrialized treatments has also meant newobstacles. The purpose of this study was to introduce andtheoretically test a method for improving dental crown fit. The optimization method allocates support points in order to check the final variation for dental crowns. Three different types of geometries were tested and compared. The three geometries were also divided into three sub-geometries: Current method, Optimized method and Feasible method. The Optimized method, using the whole surface for support points, provided the best results. The results support the objective of the study. It also seems that the support optimization method can dramatically improve the robustness of dental crown treatments.
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| 23. |
- Kero, Timo, 1973, et al.
(author)
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Process Optimization Regarding Geometrical Variation and Sensitivity Involving Dental Drill- and Implant-Guided Surgeries
- 2007
-
In: International Journal of Biomedical Sciences. ; 2:4, s. 237-243
-
Journal article (peer-reviewed)abstract
- Within dental-guided surgery, there has been a lack of analytical methods for optimizing the treatment of the rehabilitation concepts regarding geometrical variation. The purpose of this study is to find the source of the greatest geometrical variation contributor and sensitivity contributor with the help of virtual variation simulation of a dental drill- and implant-guided surgery process using a methodical approach. It is believed that lower geometrical variation will lead to better patient security and higher quality of dental drill- and implant-guided surgeries. It was found that the origin of the greatest contributor to the most variation, and hence where the foci should be set, in order to minimize geometrical variation was in the assembly category (surgery). This was also the category that was the most sensitive for geometrical variation.
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| 24. |
- Kero, Timo, 1973, et al.
(author)
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VARIATION SIMULATION TOOLKIT FOR VIRTUAL VERIFICATION OF DENTAL DRILL-GUIDED SURGERIES
- 2007
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In: III INTERNATIONAL CONGRESS ON COMPUTATIONAL BIOENGINEERING. - 9789806939103 ; , s. 333-338
-
Conference paper (peer-reviewed)abstract
- . Guided surgeries are becoming common in modern dental industry, and are used for a variety of treatments. The purpose of this study is to apply a dental software toolkit for virtual simulation of dental drill guided surgery. The hypothesis is that if a virtual simulation of dental drill guided surgery can be done, then the preplanned surgery can also be verified before the actual surgery. The dental drill guided concept is a planning and surgical implementation system that enables surgery with the help of a drill guide based on planning supported by computer aided design tools and CT-scan. The variation simulation predicts the final positions of the pre-defined critical production dimension at the apical part of the fixture. The results are based on variation simulation of two dental drill guided surgeries: Maxilla, seven implants and Mandible, nine implants. Maxilla resulted in a safe surgery while Mandible needed an optimization of the implant positions before the surgery. By analyzing the results, it was also found that both plans could be optimized in order to minimize the geometrical variation. Finally, it was found that the method used was suitable for predicting guided surgeries to achieve safer treatments.
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| 25. |
- Lindau, Björn, 1961, et al.
(author)
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Aspects of fixture clamp modeling in non-rigid variation simulation of sheet metal assemblies
- 2013
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In: Proceedings of ASME 2013 International Mechanical Engineering Congress and Exposition. - 9780791856192 ; 2 B
-
Conference paper (peer-reviewed)abstract
- Today there is an increased use of CAT-tools (Computer Aided Tolerancing) within the automotive industry. These kinds of virtual tools are getting increasingly important to ensure robust solutions as early as possible in the development processes, to minimize the use of test series and thereby reduce lead times and development costs.This paper focuses upon modeling of fixture locating scheme and the aspect of how many degrees of freedoms (DoF) a clamp actually locks. The clamps control part movement allowance, and it is of importance to investigate the influence from the friction forces between the clamping units and the fixated parts. Simulated forces in non-steering directions are compared to friction forces measured in real body shop production equipment. The non-rigid variation simulations have been performed based upon the Method of Influence Coefficients (MIC) and additional functionality for contact modeling, force estimation and weld sequence analysis.There are a variety of alternatives of how to build the simulation model and the made choices obviously influence the simulation results. The industrial case study shows significant differences in both estimated in-plane forces and geometric results after springback for different choices of modeling alternatives. It demonstrates the difficulties in taking the friction force into consideration in variation simulation of sheet metal assembly processes.
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