| 1. |
- Barth, Henrik, 1971-, et al.
(författare)
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From Traditional Manufacturing to Digital Manufacturing : Two Swedish Case Studies
- 2023
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Ingår i: Innovation - Research and Development for Human, Economic and Institutional Growth. - Rijeka : InTech. - 9781837689965 - 9781837689972 - 9781837689989
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Bokkapitel (refereegranskat)abstract
- Digital manufacturing can produce new and advanced tools more rapidly and at lower cost than traditional manufacturing. This new technology means manufacturers need to develop innovative business models adapted to this change in the manufacturing landscape. With digital manufacturing, companies have both an opportunity and a challenge. They can enter new markets where large-scale production provides competitive advantage. They can enter niche markets that become more attractive as old boundaries and structures lose relevance. Yet their additive manufactured components must meet the same standards set for conventional manufactured components. However, we know little about how companies manage this change as they make the transition from traditional manufacturing to digital manufacturing. This chapter presents two co-creation digital manufacturing projects between university researchers and Swedish companies. In each project, the goal was to develop sustainable and efficient digital production methods that offer tailor-made product solutions. Various technical methods used in the projects are described as materials, and prototypes are developed, tested, and analyzed.
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| 2. |
- Bergstedt, Edwin, 1986-
(författare)
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A Comparative Investigation of Gear Performance BetweenWrought and Sintered Powder Metallurgical Steel : Utilizing In-situ Surface Profile Measurements to Investigate theInitiation and Evolution of Micropitting and Pitting Damage
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Vehicle electrification is a strong trend that introduces new challenges, such as increased input speed of the transmission and increased power density. Alsothe noise emittance of the gearbox is of increasing importance, as the sound of the gearbox is no longer masked by the internal combustion engine. Pressed and sintered powder metallurgical steel could be an interesting alternative towrought steel; the internal porosity has a dampening effect on the noise, and gears can be made in a fast and efficient process. However, current manufacturing of powder metallurgical steel has significant performance limitations. The Nanotechnology Enhanced Sintered Steel Processing project aims to reduce the gap in performance between conventional steel and powder metallurgical steel. One of the potential benefits is that with the inclusion of nano-powder the density can be increased. To validate the new material, its performance needs to be compared to the performance of current generation powder metallurgical materials and also to wrought steel. It is therefor crucial to be able to test and evaluate different materials and gears. This thesis has developed methods for testing, comparing, and evaluating the performance of gears. Powder metallurgical steel has been tested and compared to wrought steel; the efficiency as well as pitting life have been investigated in an FZG test rig. Also the effects of different surface finishing operations have been evaluated. The gear flanks were measured in-situ in the gearbox using a stylus instrument; an optimisation routine was created to fit the measurements to the theoretical involute profile. This enabled an in-depth analysis of surface wear and presented an opportunity to investigate micropitting initiation. It was found that the damage mechanisms of wrought steel and powder metallurgical steel are similar and related to the surface finishing method. However, the powder metallurgical steel was also susceptible to sub-surface cracks. Superfinished gears can be negatively influenced by the lack of tip relief as cracks initiate in the surface layer of the root, rapidly destroying the tooth.
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| 3. |
- Braun, Greta, 1995, et al.
(författare)
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Ingenjör4.0 – A National Upskilling Programme to Bridge Industry’s Skill Gap
- 2023
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Ingår i: Procedia CIRP. - Amsterdam : Elsevier. - 2212-8271. ; 120, s. 1286-1291, s. 1286-1291
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Konferensbidrag (refereegranskat)abstract
- Manufacturing industry needs major transformation to meet disruptive environmental, social, and economic challenges, thus requiring a highly skilled workforce. This paper presents key functionalities, results, and best-practices for the launch and operation of a national upskilling platform. The Swedish upskilling programme Ingenjör 4.0's operations have been constantly user-monitored through participant surveys measuring appreciation for training content from the participants and identifying areas with potential for improvement. Thematic analysis of 137 survey responses identified dimensions relevant for an upskilling programme's success. Results show that success factors and hurdles typically lie within the following dimensions: relevance, organization and structure, working life competencies, support from teachers, and collaboration with other learners. The paper concludes that national programmes like Ingenjör4.0 can, in a short time, have deep impact on skill levels for manufacturing industries in areas such as industrial digitalization. Highlighted success factors are: participant appreciation of highly relevant content, collaboration with other participants, highly competent teachers, and the collaboration between universities. Obstacles for the learners are feelings of mismatch in challenges and prior knowledge, lack of feedback and applicable working life examples in the teaching, and the need for increased collaboration with other participants.
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| 4. |
- Flys, Olena, 1971-, et al.
(författare)
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Using confocal fusion for measurement of metal AM surface texture
- 2020
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Ingår i: Surface Topography: Metrology and Properties. - Bristol : IOP Publishing Ltd. - 2051-672X. ; 8:2
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Tidskriftsartikel (refereegranskat)abstract
- The highly complex nature of as printed metal AM surfaces pose other challenges for making measurements compared to surfaces made with many conventional processing methods. The high complexity is caused by high aspect ratios, a mix of high and low reflexivity, steep angles etc. It is not clear which method is the most suitable for measuring these surfaces. The objective of this study was to compare four different measurement modes available in one instrument to evaluate the advantages and drawbacks of the respective techniques regarding measurements of metal AM surfaces. The evaluated measurement modes are Confocal Microscopy, Coherence Scanning Interferometry, Focus Variation and Confocal Fusion. The effect of advantages and drawbacks of studied techniques was tested on typical surfaces produced by L-PBF process. Surfaces printed at 0° and 90° inclinations were compared regarding the measurement results achieved from the different methods. The Power Spectral Density analysis and visual comparison were used for the examination of studied measurements methods. Besides the comparison of areal measurements acquired by different modes available in the instrument also extracted profile measurements were compared with profile images acquired using an Optical Microscope. This study reveals that confocal fusion is a promising technique for AM surface characterisation, due to the highest amount of valid data points in the typical measurement. The new approach developed in the study showed that PSD analysis can be used for evaluation of fill in algorithms incorporated in different software. Results of the profile comparisons help to illustrate features that can be depicted by surface measurements, applying different measurement principles, as well as enables comparison of raw profile data between different types of measurements. Further investigation of measurements on AM surfaces in the frequency domain will bring more understanding about the limitations of measurement techniques.
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| 5. |
- KRISHNA, AMOGH VEDANTHA, 1990
(författare)
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Towards Topography Characterization of Additive Manufacturing Surfaces
- 2020
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Additive Manufacturing (AM) is on the verge of causing a downfall to conventional manufacturing with its huge potential in part manufacture. With an increase in demand for customized product, on-demand production and sustainable manufacturing, AM is gaining a great deal of attention from different industries in recent years. AM is redefining product design by revolutionizing how products are made. AM is extensively utilized in automotive, aerospace, medical and dental applications for its ability to produce intricate and lightweight structures. Despite their popularity, AM has not fully replaced traditional methods with one of the many reasons being inferior surface quality. Surface texture plays a crucial role in the functionality of a component and can cause serious problems to the manufactured parts if left untreated. Therefore, it is necessary to fully understand the surface behavior concerning the factors affecting it to establish control over the surface quality. The challenge with AM is that it generates surfaces that are different compared to conventional manufacturing techniques and varies with respect to different materials, geometries and process parameters. Therefore, AM surfaces often require novel characterization approaches to fully explain the manufacturing process. Most of the previously published work has been broadly based on two-dimensional parametric measurements. Some researchers have already addressed the AM surfaces with areal surface texture parameters but mostly used average parameters for characterization which is still distant from a full surface and functional interpretation. There has been a continual effort in improving the characterization of AM surfaces using different methods and one such effort is presented in this thesis. The primary focus of this thesis is to get a better understanding of AM surfaces to facilitate process control and optimization. For this purpose, the surface texture of Fused Deposition Modeling (FDM) and Laser-based Powder Bed Fusion of Metals (PBF-LB/M) have been characterized using various tools such as Power Spectral Density (PSD), Scale-sensitive fractal analysis based on area-scale relations, feature-based characterization and quantitative characterization by both profile and areal surface texture parameters. A methodology was developed using a Linear multiple regression and a combination of the above-mentioned characterization techniques to identify the most significant parameters for discriminating different surfaces and also to understand the manufacturing process. The results suggest that the developed approaches can be used as a guideline for AM users who are looking to optimize the process for gaining better surface quality and component functionality, as it works effectively in finding the significant parameters representing the unique signatures of the manufacturing process. Future work involves improving the accuracy of the results by implementing improved statistical models and testing other characterization methods to enhance the quality and function of the parts produced by the AM process.
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| 6. |
- Rebeggiani, Sabina, 1980-, et al.
(författare)
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A measure of perceived quality to secure the polishability of new paint systems
- 2023
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Ingår i: Surface Topography: Metrology and Properties. - Bristol : Institute of Physics (IOP). - 2051-672X. ; 11:2
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Tidskriftsartikel (refereegranskat)abstract
- The automotive industry continuously strives to reduce their environmental impact. For the paint shop it means to introduce more sustainable paint concepts, while maintaining the production rate and retain the right surface appearance that is crucial for the vehicle’s perceived quality. Today most painted parts are visually inspected and, if needed, manually repaired by abrasive polishing to eliminate spot defects. The repair process consists of one sanding step to remove the defect, and one or two rubbing/polishing steps to restore the surface, but still it tends to be a non-reliable process leaving patterns or clusters of shallow micro scratches seen as three-dimensional shapes moving over the surface when viewed from different angles like holograms. These so called ‘polishing roses’ are hard to detect in artificial light but clearly visible in Sunlight and therefore they constitute a constant quality issue. Accurate polishing procedures in combination with more objective inspection techniques would secure a high surface quality—but what is ‘accurate’? The overall scope of the study was to deepen the knowledge of paint systems to develop test routines for the polishability of coatings already during the development stage, and thereby ease the implementation of new coating systems in production. The study was based on collected process data from professional polishers to define a process window based on key parameters for successful end-of-line repairs of coated surfaces, i.e. strategies minimizing the occurrence of visible polishing traces. A CNC-machine was built up for the purpose to systematically test and evaluate new coating systems and repair procedures. The surface estimation was made by visual inspections as well as by a further developed photometric stereo system providing quantitative images of remaining repair traces. © 2023 IOP Publishing Ltd
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| 7. |
- Rebeggiani, Sabina, 1980-, et al.
(författare)
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On communicating extruded aluminium surface quality along the supply chain : a customer approach to sustainable surfaces
- 2023
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Ingår i: Surface Topography: Metrology and Properties. - Bristol : Institute of Physics (IOP). - 2051-672X. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Today, far too many products are scrapped due to surface related issues, products with perfect function but with minor surface blemishes. The complaints are often offset by goodwill commitments from suppliers at great cost to them and delivery delays and lead time costs for customers. The reason is that the industry relies on several non-standardized classification systems for surface quality that are based on various combinations of and designations for surface defects, assessed by visual inspections at a defined distance to determine the severity of any detected surface deviations. These similar classification systems provide far too much scope for subjective and non-repeatable assessments causing communication problems between customer and producer at all stages in the supply chain. To challenge this situation, a common toolbox to communicate, describe and define surface quality should be developed, i.e. a standardisation of surface quality assessment including various effects and defects with a jointly established nomenclature and evaluation parameters. This work presents the first step of a research project bringing together 11 suppliers and OEMs along the supply chain, from the delivery of raw aluminium to finished alumina profiles included in consumer products. The final goal of the project is to develop an ‘objective classification of visual requirements’ on alumina profiles towards increased sustainability and decreased material wastage. Presented result is a common terminology with links to the process chain, surface defect geometry and visual appearance aiming at making the communication between producers and buyers of the aluminium profiles clearer and more unambiguous when it comes to specification and requirements of profile surfaces in each of the supply-chain links. Future work will add measurable parameters specifying surface quality.
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| 8. |
- Rebeggiani, Sabina, 1980-, et al.
(författare)
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Towards an Objective Classification of Extruded Aluminum Surfaces-A Literature Review and Case Study
- 2022
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Ingår i: SPS2022: Proceedings of the 10th Swedish production symposium. - Amsterdam : IOS Press. - 9781643682686 - 9781643682693 ; , s. 51-62
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Konferensbidrag (refereegranskat)abstract
- Large costs and lead-time losses are created by returned aluminum products - to a great extent unnecessarily. Much of the metal product complaints are due to visual surface defects. Today, the aluminum industry relies on several non-standardized classification systems for surface quality assessments which provides far too much scope for subjective and non-repeatable surface estimations. To challenge this situation, a common toolbox to describe and define surface quality in a more objective way needs to be developed. A first step towards such standardization is to speak the same language, thus this study is based on a state-of-the-art survey covering terminology and descriptions of surface defects in literature, and a round-robin assessment collecting terms used by employees at seven companies within the aluminum industry. The literature study showed that most attempts to catalog and categorized various types of defects on commercial aluminum extrusions are based on the origin of defects and how to prevent and/or reduce them, thus the vocabulary is production-oriented and most terms are not useful from the customers' nor the designers' point of view when coming to describe desired surface effect, i.e. perceived surface quality. The round-robin assessment confirmed the large variation of terminology used, and that defects were judged differently also within the same company due to experience and field of work. A common vocabulary is suggested to be based on the relationships between used expressions; from general terms at stages linked to consumers, designers and sale, tracing towards more technical terms the closer the stage where the origin of the defect can be found. This structure, in combination with e.g. manufacturing cost, is expected to guide customers towards more sustainable surface quality choices that, together with more consistent surface assessments along the production chain, is expected to strongly reduce unnecessary scrapping.
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| 9. |
- Reddy, Vijeth Venkataram, 1990-, et al.
(författare)
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Characterisation and analysis of the surface texture of injection-moulded automotive interior ABS and PP components
- 2023
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Ingår i: The International Journal of Advanced Manufacturing Technology. - London : Springer. - 0268-3768 .- 1433-3015. ; 128:9-10, s. 4579-4592
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Tidskriftsartikel (refereegranskat)abstract
- Interior automotive plastic components are often manufactured by injection moulding since this technique enables cost-efficient manufacturing, large design freedom, and easy integration of functions. However, to obtain a high-quality impression, it is important to produce components with uniformity in texture, colour, and gloss. Unfortunately, this is rather difficult since a large number of material and processing parameters affect the surface topography and thereby the texture, colour, and gloss. It is therefore important to improve the understanding of how different material and processing parameters affect the surface topography, and in the present study, the influence on surface topography of ABS (Acrylonitrile Butadiene Styrene) and PP (Polypropylene) by melt temperature, tool temperature, and injection speed is investigated by coherence scanning interferometry. Area scale analysis is used to identify the wavelengths of interest, and areal surface parameters are statistically screened to identify robust surface parameters that can be used to discriminate between the surfaces and quantify the influence on surface topography by different material and process variables. Results from the study suggest that tool temperature and injection speed have significant influence on certain surface parameters and, particularly, arithmetic mean height (Sa) and root mean square gradient (Sdq) by approximately 40%, core material volume (Vmc) by 35%, and core roughness depth (Sk) by 50%. These surface parameters are identified as significant and used to discriminate between the sample surfaces. © 2023, The Author(s).
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| 10. |
- Reddy, Vijeth Venkataram, 1990
(författare)
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On Deterministic feature-based Surface Analysis
- 2020
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Manufacturing sector is continuously identifying opportunities to streamline production, reduce waste and improve manufacturing efficiency without compromising product quality. Continuous improvement has been the primary objective to produce acceptable quality products and meet dynamic customer demands by using advanced techniques and methods. Considering the current demands from society on improving the efficiency with sustainable goals, there is considerable interest from researchers and industry to explore the potential, to optimize- and customize manufactured surfaces, as one way of improving the performance of products and processes. Every manufacturing process generate surfaces which beholds certain signature features. Engineered surfaces consist of both, features that are of interest and features that are irrelevant. These features imparted on the manufactured part vary depending on the process, materials, tooling and manufacturing process variables. Characterization and analysis of deterministic features represented by significant surface parameters helps the understanding of the process and its influence on surface functional properties such as wettability, fluid retention, friction, wear and aesthetic properties such as gloss, matte. In this thesis, a general methodology with a statistical approach is proposed to extract the robust surface parameters that provides deterministic and valuable information on manufactured surfaces. Surface features produced by turning, injection molding and Fused Deposition Modeling (FDM) are characterized by roughness profile parameters and areal surface parameters defined by ISO standards. Multiple regression statistics is used to resolve surfaces produced with multiple process variables and multiple levels. In addition, other statistical methods used to capture the relevant surface parameters for analysis are also discussed in this thesis. The selected significant parameters discriminate between the samples produced by different process variables and helps to identify the influence of each process variable. The discussed statistical approach provides valuable information on the surface function and further helps to interpret the surfaces for process optimization. The research methods used in this study are found to be valid and applicable for different manufacturing processes and can be used to support guidelines for the manufacturing industry focusing on process optimization through surface analysis. With recent advancement in manufacturing technologies such as additive manufacturing, new methodologies like the statistical one used in this thesis is essential to explore new and future possibilities related to surface engineering.
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