| 1. |
- Schultheiss, Fredrik, et al.
(författare)
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Cost Optimization by Incremental Production Improvements of Metal Cutting Operations
- 2011
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Ingår i: [Host publication title missing]. ; , s. 540-547
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Konferensbidrag (refereegranskat)abstract
- The focus of this project has been to find a method on how to do production improvements systematically in the case of manufacturing by means of metal cutting operations. Typically every company determines their cutting data with the help of previous experiences as well as recommendations made by the tool manufacturers. These chosen cutting data may be the optimal settings for the specific operation although the probability for this is very slim. Some large companies have resources to investigate and find the optimum cutting data by themselves but this is usually not the case for SMEs. These companies need a clear and logical method on how to find the machining optimum while not causing too many delays or scraped parts during the normal production. The goal of this research was to find a method to incrementally optimize the production in terms of manufacturing costs of the machined parts in SMEs. The proposed method is illustrated by an analysis of the results obtained from a case study at a small Swedish company. The present work constitutes a good foundation for the optimization of the production process and thereby has a strong relevance toward the area of sustainable production.
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| 2. |
- Schultheiss, Fredrik, et al.
(författare)
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Machinability of duplex stainless steels - A study with focus on the tool wear behaviour
- 2011
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Ingår i: [Host publication title missing]. ; , s. 271-277
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Konferensbidrag (refereegranskat)abstract
- This article presents research done in order to analyse the machinability of duplex stainless steel with coated carbide tools during turning operations. Although duplex stainless steel has existed for about 70 years fairly little work has been published in the area of investigating the different aspects of the machining of these materials. In this research project three different kinds of duplex stainless steels and their properties have been examined. These materials where SAF 2507, SAF 2205 and LDX 2101 which together covers a large part of the duplex stainless steels that are commercially available today. This study focuses on analysing the tool wear behaviour in an attempt to better understand the actual wear patterns during machining, not only the more traditional ones that are in common use today. Some additional tests were also done in order to get a better understanding of the machinability of duplex stainless steel in general. Theories and concepts that are related to the analysing of machinability will be presented, most of which have been previously validated and in use for a long time. Adhesive wear of the cutting tool, in many cases severe, was to some extent found at all different cutting data investigated.
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| 3. |
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| 4. |
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| 5. |
- Agmell, Mathias, et al.
(författare)
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A fully coupled thermomechanical two-dimensional simulation model for orthogonal cutting: formulation and simulation
- 2011
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Ingår i: Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture. - : SAGE Publications. - 0954-4054 .- 2041-2975. ; 225:B10, s. 1735-1745
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Tidskriftsartikel (refereegranskat)abstract
- In this paper a fully coupled thermomechanical two-dimensional simulation model for orthogonal cutting is presented. The model is based on the arbitrary Lagrangian-Eulerian formulation with the remeshing technique. The material model used for the workpiece material includes Johnson-Cook plasticity, and as the chip separation criterion the Johnson-Cook damage law is employed. The different friction zones are modelled by the Coulomb friction law with a maximum limit for the friction. The capability of the model to represent the cutting process realistically is validated by performing simulations for different feed depths. The model is validated by comparison of the simulated values and measured experimental data for several different important process parameters, such as the feed force, the cutting force, the chip thickness ratio, the relative deformation widths, and the temperature distribution. The results from the simulations showed very good agreement with the experimental data.
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| 6. |
- Agmell, Mathias, et al.
(författare)
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A numerical and experimental investigation of the deformation zones and the corresponding cutting forces in orthogonal cutting
- 2011
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Ingår i: Advanced Materials Research. - 1022-6680 .- 1662-8985. - 9783037850954 ; 223, s. 152-161
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Konferensbidrag (refereegranskat)abstract
- Abstract in UndeterminedThis study are focused on the deformation zones occurring in the work piece in a machining process and the corresponding cutting forces. The fully coupled thermo-mechanical FE-model for orthogonal cutting, developed in [1] is utilized. The work piece material is modeled with Johnson-Cook plasticity including damage formulation. Simulations for different feed depths were performed. The cutting forces, the chip thickness ratio and the deformation widths were determined experimentally by the quick-stop images and a force measurements. The results from the simulations have been compared to experimental data for the cutting forces and the chip thickness ratio as a function of the theoretical chip thickness.
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| 7. |
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| 8. |
- Agmell, Mathias, et al.
(författare)
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Identification of plasticity constants from orthogonal cutting and inverse analysis
- 2014
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Ingår i: Mechanics of Materials. - : Elsevier BV. - 0167-6636. ; 77, s. 43-51
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this work is that from experimental determined cutting process parameters be able to predict the plasticity input constants to Finite Element Method (FEM) models. In the present study the Johnson-Cook constitutive model constants are determined on the basis of cutting process parameters in orthogonal cutting and by use of inverse analysis. Previously established links between Johnson-Cook constitutive model constants and cutting process parameters in the cutting process such as primary cutting force and chip compression ratio is used serve as a starting point in the inverse analysis. As a reference material AISI 4140 has been chosen in this study, which is a tempered steel. The Johnson-Cook constitutive model constants in the reference material are being changed within an interval of ±30 %. The inverse analysis is performed using a Kalman filter. The material model for the reference material is validated on the basis of the experimental results in previous work. The model showed to predict the cutting process parameters with a high level of accuracy. The predicted Johnson-Cook constitutive model constants in the present study achieve an error between simulated- and experimental cutting process parameters of maximum 2%. The method described in this study is not limited to identify Johnson-Cook constitutive model constants, but the method can also be used for other constitutive models. The same applies to the process itself and the selected cutting process parameters, but orthogonal cutting has been used to illustrate and validate this method.
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| 9. |
- Agmell, Mathias, et al.
(författare)
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Modelling Subsurface Deformation in High Speed Machining of Inconel 718
- 2012
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Konferensbidrag (refereegranskat)abstract
- Abstract in UndeterminedTraditionally, the development and optimization of the machining process with regards to the sub-surface deformation is done through experimental method which is often expensive and time consume. This paper presents the development of a FE-simulation model to predict the depth of sub-surface deformation induced in the high speed machining of Inconel 718 by use of whisker-reinforced ceramic tool. The effects of cutting parameters and geometry on sub-surface deformation will be simulated by developed FE model. In addition to FE model, the experimental study was made to validate the results of FE model. Characterization of sub-surface deformation produced under different machining parameters and tool conditions was made by EBSD and in the cutting and feed directions.
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| 10. |
- Agmell, Mathias, et al.
(författare)
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The link between plasticity parameters and process parameters in orthogonal cutting
- 2013
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Ingår i: 14th CIRP Conference on Modeling of Machining Operations (CIRP CMMO). - : Elsevier BV. - 2212-8271. ; 8, s. 224-229
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Konferensbidrag (refereegranskat)abstract
- In the present study the plasticity parameters in the Johnson Cook plasticity model are determined on the basis of process parameters in orthogonal cutting by use of inverse analysis. Previously established links between material parameters and process parameters in the cutting process such as chip thickness ratio, cutting forces, temperatures, deformation zones, is used serve as a starting point in the inverse analysis. The material AISI 4140 is simulated using the model employed in [1], the Johnson Cook parameters being changed within an interval of ±30 %. The inverse analysis is performed using a Kalman filter. The material model for the reference point is validated on the basis of the experimental results in [1], the model being shown to predict the process parameters with a high level of accuracy. The attempt is made to establish a link for materials having cutting process characteristics that are similar between certain process parameters and the Johnson Cook parameters in order to be able to predict the input parameters to FEM models using experimental data from a cutting process.
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| 11. |
- Andersson, Carin, et al.
(författare)
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Experimental studies of cutting force variation in face milling
- 2011
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Ingår i: International Journal of Machine Tools & Manufacture. - : Elsevier BV. - 0890-6955. ; 51:1, s. 67-76
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this paper is to present a developed cutting force model for multi-toothed cutting processes, including a complete set of parameters influencing the cutting force variation that has been shown to occur in face milling, and to analyse to what extent these parameters influence the total cutting force variation for a selected tool geometry. The scope is to model and analyse the cutting forces for each individual tooth on the tool, to be able to draw conclusions about how the cutting action for an individual tooth is affected by its neighbours. A previously developed cutting force model for multi-toothed cutting processes is supplemented with three new parameters; eccentricity of the spindle, continuous cutting edge deterioration and load inflicted tool deflection influencing the cutting force variation. A previously developed milling force sensor is used to experimentally analyse the cutting force variation, and to give input to the cutting force simulation performed with the developed cutting force model. The experimental results from the case studied in this paper show that there are mainly three factors influencing the cutting force variation for a tool with new inserts. Radial and axial cutting edge position causes approximately 50% of the force variation for the case studied in this paper. Approximately 40% arises from eccentricity and the remaining 10% is the result of spindle deflection during machining. The experimental results presented in this paper show a new type of cutting force diagrams where the force variation for each individual tooth when two cutting edges are engaged in the workpiece at the same time. The wear studies performed shows a redistribution of the individual main cutting forces dependent on the wear propagation for each tooth.
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| 12. |
- Andersson, Carin, et al.
(författare)
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Grinding or shaving - economic decision support in the production of gears
- 2014
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Ingår i: ; , s. 1-8
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Konferensbidrag (refereegranskat)abstract
- This paper describes a case study at an automotive company with the purpose ov developing an economically based decision support tool, for strategic decision about wheather to chose grinding or shaving as a finishing method in gear manufacturing. In the study different cost models are compared regarding input parameters in alignment with the required input data required to make a decision. With the performance driven cost model used during the analysis, shaving was shown to be the most cost efficient finishing method.
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| 13. |
- Andersson, Carin, et al.
(författare)
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Manufacturing costs as a decisionsupport in production developoment and relocation issues - a case study at a supplier to the automotive industry
- 2014
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Ingår i: ; , s. 1-10
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Konferensbidrag (refereegranskat)abstract
- This paper will present a case study at a Swedish subcontractor, were a performance driven manufacturing cost model is used to analyse different production development scenarios in relation to sourcing. The result shows that production performance in terms of downtime, speed rate and quality losses will have a significant impact on manufacturing costs. The cost model was used to obtain cost scenarios for different offshoring alternatives serving as a decision support for the company management. Based on these scenarios they decided not to offshore production, instead they realized the potential of developing the Swedish site according to the proposed scenario.
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| 14. |
- Andersson, Carin, et al.
(författare)
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Modeling of maintenance costs
- 2011
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Konferensbidrag (refereegranskat)abstract
- Abstract in Undetermined Increased global competition demands for increased manufacturing costs awareness. Maintenance activities and strategies have been studied extensively, but few studies discuss maintenance costs. This paper presents a model for calculating performance-driven manufacturing costs (in currency/piece), including parameters for determining the maintenance costs in relation to the total manufacturing costs. This study focus on developing an existing manufacturing part cost model involving parameters driving maintenance costs. A proposal of the allocation of different maintenance activities to different costs parameters is discussed together with the utilization of the model in an industrial case study.
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| 15. |
- Bushlya, Volodymyr, et al.
(författare)
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Characterization of White Layer Generated when Turning Aged Inconel 718
- 2011
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Ingår i: Procedia Engineering. - : Elsevier BV. - 1877-7058. ; 19, s. 60-66
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Konferensbidrag (refereegranskat)abstract
- Abstract in UndeterminedWhite layer formation is considered as a part of minimum array of parameters characterizing surface integrity of the machined product. The paper is aimed on identification and characterization of white layer generated when finish turning aged Inconel 718 with Al2O3-SiCw ceramic tools under different cutting conditions, tool wear and coolant application. As expected intensity of white layer formation was proportional to cutting speed and tool wear. High resolution transmission electron microscopy (HRTEM) performed on white layer revealed formation of nanostructured material with grain size of 50-150 nm. Long-term ultrasonic-assisted etching of white layer allowed to uncover its morphology, where subsequent AFM measurements confirmed HRTEM findings. Observations by high resolution SEM provided evidence that gamma' Ni-3(Al,Ti) phase remained intact. (C) 2012 Published by Elsevier Ltd. Selection and peer-review under responsibility of Prof. E. Brinksmeier
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| 16. |
- Bushlya, Volodymyr, et al.
(författare)
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Effect of Cutting Conditions on Machinability of Superalloy Inconel 718 During High Speed Turning with Coated and Uncoated PCBN Tools
- 2012
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Ingår i: 45th CIRP Conference on Manufacturing Systems 2012. - : Elsevier BV. - 2212-8271. - 9781627485128 ; 3, s. 370-375
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Konferensbidrag (refereegranskat)abstract
- Inconel 718, an efficient superalloy for energy and aerospace applications, is currently machined with cemented carbide tools at low speed (vc≈60 m/min) due to its unfavorable mechanical and thermal properties. The article presents results of superalloy machinability study with uncoated and coated PCBN tools aiming on increased speed and efficiency. Aspects of tool life, tool wear and surface integrity were studied. It was found that protective function of the coating, increasing tool life up to 20%, is limited to low cutting speed range. EDX and AFM analyses suggested dominance of chemical and abrasive wear mechanisms. Residual stress analysis has shown advantageous compressive surface stresses.
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| 17. |
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| 18. |
- Bushlya, Volodymyr, et al.
(författare)
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Effects of Cutting Speed when Turning Age Hardened Inconel 718 with PCBN Tools of Binderless and Low-CBN Grades
- 2013
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Ingår i: Machining Science and Technology. - : Informa UK Limited. - 1091-0344 .- 1532-2483. ; 17:4, s. 497-523
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Tidskriftsartikel (refereegranskat)abstract
- Application of polycrystalline cubic boron nitride (PCBN) tools as an alternative for ceramic and cemented carbide tools in machining superalloys has been frequently identified as a solution for enhancing process efficiency but only a limited number of studies has been done in this area. The current study explores the effect of the cutting speed, which was varied in a wide range (2-14m/s), on machinability of age hardened Inconel 718 with PCBN tools. Performance of binderless PCBN grade and grade with low-cBN content was evaluated in terms of tool life, tool wear, cutting forces and surface quality. Chip formation and process dynamics were analyzed as well. It was found that low-cBN grade provided 70-90% better surface finish and tool life than the binderless at moderate speeds (5-8m/s). Performance of both grades at low and high speed ranges was non-satisfactory due to notching and flaking respectively. At low cutting speed adhesive wear plays a major role while as the speed increases a chemical wear becomes dominant.
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| 19. |
- Bushlya, Volodymyr, et al.
(författare)
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Modeling and experimentation on multistage work-hardening mechanism in machining with nose-radiused tools and its influence on machined subsurface quality and tool wear
- 2014
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Ingår i: International Journal of Advanced Manufacturing Technology. - : Springer Science and Business Media LLC. - 0268-3768 .- 1433-3015. ; 73:1-4, s. 545-555
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Tidskriftsartikel (refereegranskat)abstract
- The paper reports on the modeling and respective experimental validation for the formation of the machined subsurface layer in turning with nose-radiused and round tools. An experimental work on the mechanisms of work-hardening of the machined surface and related wear of the cutting tools was conducted for high-speed turning of aged Inconel 718 with whisker-reinforced alumina tools. The model shows that multiple deformations of the machined surface occur when machining with small feeds and tools with large nose radius, thus changing the mechanics of surface formation. Experimental results confirm the localized increase in subsurface hardness in the vicinity of the tool tip. The variation in the degree of work-hardening and the extent of the area affected by it fully agree with the predictions of the model. The model also shows that a significant part of the cutting tool may cut through the extra work-hardened material. Tool wear tests show that the local increase in workpiece hardness results in a localized increase in the wear rate of the cutting tools.
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| 20. |
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| 21. |
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| 22. |
- Bushlya, Volodymyr, et al.
(författare)
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Performance and wear mechanisms of whisker-reinforced alumina, coated and uncoated PCBN tools when high-speed turning aged Inconel 718
- 2013
-
Ingår i: International Journal of Advanced Manufacturing Technology. - : Springer Science and Business Media LLC. - 0268-3768 .- 1433-3015. ; 66:9-12, s. 2013-2021
-
Tidskriftsartikel (refereegranskat)abstract
- Abstract in UndeterminedInconel 718, an efficient superalloy for energy and aerospace applications, is currently machined with cemented carbide tools at low speed (vc≈60 m/min) due to its unfavorable mechanical and thermal properties. The article presents results of a study of superalloy machinability with whisker reinforced alumina, uncoated and coated PCBN tools. Turning of age hardened Inconel 718 (45 HRC) was done under high speed machining conditions (vc=250…350 m/min). Aspects of tool life, tool wear and generated surface quality were studied. Application of uncoated PCBN tools resulted in surface quality and force level superior to other tool materials. Considerable side-flow of workpiece material was found to affect surface quality, especially for coated PCBN and ceramic tools. It was found that protective function of the coating, which increases the tool life up to 20%, is limited only to low cutting speed range. EDX and AFM analyses suggested dominance of chemical and abrasive wear mechanisms. EDX mapping of worn tools pointed absence of diffusional wear for PCBN tools and intensive degradation of whisker reinforcement in ceramic tools due to diffusion of Ni, Fe and Cr.
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| 23. |
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| 24. |
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| 25. |
- Bushlya, Volodymyr, et al.
(författare)
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Tool wear and tool life of PCBN, binderless cBN and wBN-cBN tools in continuous finish hard turning of cold work tool steel
- 2014
-
Ingår i: Journal of Superhard Materials. - 1934-9408. ; 36:1, s. 49-60
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Tidskriftsartikel (refereegranskat)abstract
- The paper presents the results of comparative study of performance of cutting tools made of ceramic-bound, binderless cBN, and wBN-cBN tool materials. The tool performance was assessed by tool wear-resistance, values of cutting forces, parameters of machined surface quality, and the state of sub-surface layer generated in continuous turning of hardened cold work tool steel. The tests were carried out under conditions of high speed machining (v (c) = 120-180 m/min) both with and without a coolant. The best tool performance by the above-mentioned criteria is provided by a low-cBN material with ceramic binder.
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| 26. |
- Bushlya, Volodymyr, et al.
(författare)
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Wear mechanisms of silicon carbide-whisker-reinforced alumina (Al2O3-SiCw) cutting tools when high-speed machining aged Alloy 718
- 2013
-
Ingår i: International Journal of Advanced Manufacturing Technology. - : Springer Science and Business Media LLC. - 0268-3768 .- 1433-3015. ; 68:5-8, s. 1083-1093
-
Tidskriftsartikel (refereegranskat)abstract
- The paper is aimed at the identification and characterization of wear mechanisms of SiC whisker-reinforced alumina when turning aged Alloy 718 under different cutting conditions and when machining dry and with coolant. Secondary and backscatter electron microscopy accompanied by focus ion beam milling and EDX techniques were used for analysis of worn-out tools. Notch wear on the major cutting edge was found to consist of two notches: depth-of-cut notch and secondary notch located outside the chip area. The last was found to be governed by adhesion and attrition associated with adverse chip flow conditions. Formation of a minor notch was related to attrition by the defects found on the machined surface. Diffusion of Ni, Fe, and Cr into SiC whiskers was found to degrade them and facilitate adhesion. Chemical wear mechanisms were found to be responsible for degradation and decomposition of whiskers and formation of tribolayer on tool surfaces, which in turn was related to the reduced adhesion of Alloy 718 on the tool. Cracking on the tool rake and localized plastic deformation were found to further accelerate tool deterioration.
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| 27. |
- Chen, Ling, et al.
(författare)
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Modeling effect of surface roughness on nanoindentation tests
- 2013
-
Ingår i: Procedia CIRP. - : Elsevier BV. - 2212-8271. ; 8, s. 334-339
-
Konferensbidrag (refereegranskat)abstract
- Surface roughness is a commonly used criterion for characterization of surface quality in a machining operation. In the study of micro-scale mechanical properties of machined surface and cutting tool with nanoindentation, prefect surface finish on the test specimen is often required for the reliable result. However, the prefect surface finish is often difficult to obtain from the machining operation due to the limitation of the cutting tool geometry and machining dynamics. In presented paper, the effect of surface roughness on nanoindentation measurement was investigated by using finite element method. A 3D finite element model with three levels of surface roughness was developed to simulate the load-displacement indentation process with a Berkovich indenter. The material used in the simulation is AISI 316L stainless steel and it was modeled as an elastic-plastic von Misses material. Three levels of surface roughness, Ra, are used in the simulation, including 2 nm, 20 nm and 37 nm. The mechanical properties were calculated by combined simulation with the Oliver-Pharr method. The hardness and reduced modulus from the simulation was found to decrease with an increase of roughness. The scatter of load-depth curves and deviation of hardness and reduced modulus are affected by the changing of roughness. The height of pile-up was little affected by the surface roughness from the simulation. Combined effect of indenter tip radius and surface roughness was also investigated.
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| 28. |
- Chen, Ling, et al.
(författare)
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Numerical and experimental study of the roughness effects on mechanical properties of AISI316L by nanoindentation
- 2014
-
Ingår i: Modeling and Numerical Simulation of Material Science. - 2164-5345.
-
Tidskriftsartikel (refereegranskat)abstract
- Surface roughness is a commonly used criterion for characterization of surface quality in a ma-chining operation. In the study of micro-scale mechanical properties of machined surface and cut-ting tool using nanoindentation method, perfect surface finish on the specimen is often required for the reliable indentation result. However, the perfect surface finish is often difficult to obtain from the machining operation due to the dynamic behavior of the machining and the limitation of the cutting tool geometry. In the presented paper, the effect of surface roughness on the nanoindentation measurements is investigated by using finite element method. A 3D finite element model with seven levels of surface roughness is developed to simulate the load-displacement behavior in a indentation process with a Berkovich indenter. The material used in the simulation is AISI 316L stainless steel, modeled as an elastic-plastic von Misses material. The mechanical properties were calculated by combining simulations with the Oliver-Pharr method. The hardness and reduced modulus from the simulation were found to decrease with an increase of roughness. The study showed that the scatter of the load-depth curves and the deviation of the hardness and the reduced modulus are significant affected by the variation of roughness. It was also found that the height of pile-up was little affected by the surface roughness from the simulation. The combined effect of indenter tip radius and surface roughness was also investigated. The study was complemented with experimental tests and the results from these tests support the results from the simulation.
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| 29. |
- Fallqvist, Mikael, 1982-, et al.
(författare)
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Influence of the tool surface micro topography on the tribological characteristics in metal cutting – Part I Experimental observations of contact conditions
- 2013
-
Ingår i: Wear. - : Elsevier BV. - 0043-1648 .- 1873-2577. ; 298, s. 87-98
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Tidskriftsartikel (refereegranskat)abstract
- The influence of surface micro topography of CVD α-Al2O3 coatings, deposited on cemented carbide inserts, on tribological characteristics in sliding contact and in metal cutting has been investigated using quenched and tempered steel as counter/work material. Pin-on-disc and turning tests were carried out and post-test characterization using 3D optical surface profilometry and scanning electron microscopy was performed in order to investigate the tribological response of the coatings. The results show that surface micro topography can have a significant impact on the tribological performance of Al2O3 coatings under initial and cutting contact conditions. For both kinds of tests the tendency for transfer of workpiece material strongly increases with increasing coating micro topography. In the pin-on-disc tests, a smooth coating surface significantly reduces the friction coefficient. In the turning tests the contact conditions at the flank face increase with decreasing micro topography. In contrast, no general conclusions can be drawn regarding the influence of coating micro topography on the contact conditions at the rake face. The resulting topography of the turned surface was found to increase with increasing coating topography.
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| 30. |
- Frogner, Kenneth, et al.
(författare)
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A new concept of coil design for industrial induction heating
- 2011
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Ingår i: Proceedings of the Swedish Production Symposium 2011, SPS11.
-
Konferensbidrag (refereegranskat)abstract
- Abstract in UndeterminedThe demands for energy efficent heating solutions for the manufacturing industry can be met by a new induction heating platform, presented in this article. A new concept and technology to design and manufacture induction heating units is explained, evaluated and tested with successful results. The so called Greenheat technology relies on inductors built on Litz wiring moulded in soft magnetic composite; a flux conducting material produced using rotational casting methods. The aim of the article is to present and verify a hyphotesis of greatly improved induction heating results when modifying a traditional inductor design in four dependent steps. The verification is done using analytic solutions and FEM simulations as well as by experimetal work, clearly showing higher heating efficiency, no requirement for advanced cooling and a higher geometrical flexibility compared to existing heating solutions.
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| 31. |
- Frogner, Kenneth, et al.
(författare)
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Industrial heating using energy efficient induction technology
- 2011
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Ingår i: Proceedings of the 44th CIRP International Conference on Manufacturing Systems.
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Konferensbidrag (refereegranskat)abstract
- Abstract in UndeterminedThe demands for energy efficent heating solutions for the manufacturing industry can be met by a newinduction heating platform, presented in this article. A new concept and technology to design andmanufacture induction heating unit is presented, as well as a prototype induction heater, evaluated and testedin an industrial environment. Improvements compared to existing heating solutions can be clearly shown, e.g.higher heating efficiency, no requirement for advanced cooling, a higher geometrical flexibility and alsoenvironmental gains. The Greenheat platform is built on Litz wiring, SMC flux conductors, and a castingtechnology which is outlined in the article.
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| 32. |
- Fyhr, Pontus, et al.
(författare)
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A modular framework for evaluation of electrical machine production costs
- 2013
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Ingår i: 3rd International Electric Drives Conference (E|DPC). ; , s. 136-140
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Konferensbidrag (refereegranskat)abstract
- A framework structure for solving multiple option production economic models is described, showing the possibilities in defining independent process modules according to a defined set of rules. The modules are then scanned and inserted into appropriate locations in the solver framework based on naming scheme and linking information, allowing both re-use of knowledge as well as rapid development and deployment of models for new production. The methodology is applied to the production of an electric machine, showing the ability to assess options with regard to for example technical infeasibilities such as the combination of incompatible production method selections, splitting and joining process flows and maintaining a continuous solution space. The structured framework approach also allows extraction of data from any point in the production flow, for any option or nominal batch size.
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| 33. |
- Fyhr, Pontus, et al.
(författare)
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Cost drivers and production limitations for electrified vehicle traction components
- 2012
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Ingår i: [Host publication title missing]. - 9789175197524 ; , s. 405-410
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Konferensbidrag (refereegranskat)abstract
- The automotive industry is shifting from internal combustion engines towards electrified drivetrains, containing electrical machines, power electronics and battery systems. The major hurdle in gaining customer acceptance for this type of drivetrain is the increase in price, due to hybrid drivetrains featuring an additional power system and pure electric systems requiring a major investment in energy storage. This paper details two of these systems with regards to their production processes, supply limitations and cost drivers.
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| 34. |
- Fyhr, Pontus, et al.
(författare)
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Production Cost Case Generation by a Recursive Monte-Carlo Method in Electrical Machine Production
- 2014
-
Ingår i: [Host publication title missing].
-
Konferensbidrag (refereegranskat)abstract
- Electrical machine production is a multi-disciplinary area, comprising traditional mechanical processes such as sheet metal cutting, chemical processes for insulation and electrical for the working principles. In manufacturing, high throughput automation of coilwinding and sheet-cutting is combined with complex assembly, such as slotting the coils, often performed manually, but with increasing interest in automation. Followed by inherently slow processes such as the curing of resins for insulation, this poses a very difficult challenge for production system designers. Selecting the most efficient combination of low and high cycle time processes, appropriate levels of automation and sufficient buffer levels, while minimizing investments and work in progress costs.
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| 35. |
- Fyhr, Pontus, et al.
(författare)
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Statistical interfaces for production of a permanent magnet based rotor
- 2014
-
Ingår i: Electric Drives Production Conference (EDPC), 2014 4th International. - 9781479950089 ; , s. 1-6
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Konferensbidrag (refereegranskat)abstract
- A production-system simulation model for manufacturing cost of a permanent-magnet based rotor, analyzing the influence of uncertain parameters by utilizing the Monte Carlo method. The uncertain parameters studied include investment and bill of materials costs as well as cycle time. The resulting influence of these uncertainties are presented for each case individually, as well as all possible combinations, giving seven total cases studied. Cutting tool costs over a range of batch sizes show that investment uncertainty has rapidly declining impact even within fairly low batch sizes. BOM cost variations, especially for the permanent magnets maintain a sizeable influence over the range of batch sizes. The Weibull distribution based model for permanent magnet insertion shows that profit margins derived from point based nominal data is not reliable for pricing of manual production processes. The presented approach is useful both for decision making regarding new production, as well as pricing in competitive markets with narrow margins.
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| 36. |
- Fyhr, Pontus, et al.
(författare)
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The scale of permanent magnet materials for automotive traction motors
- 2012
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Ingår i: [Host publication title missing]. - 9781467330060 ; , s. 235-241
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Konferensbidrag (refereegranskat)abstract
- A mathematical model is developed with the purpose of estimating the scale of permanent magnet materials consumption in hybrid and electric automotive traction systems. These estimations are compared to consumption figures from industries such as wind power, HVAC, consumer electronics and industrial machinery. The estimations generated are useful in strategic decision-making for production planning.
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| 37. |
- Gabrielson, Per, et al.
(författare)
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Indication of cracking during pressing of advanced thin plates using an AE-based monitoring system
- 2010
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Ingår i: Tools and Technologies for the Processing of Ultra High Strength Steels: IDDRG Conference Proceedings ; 50th Anniversary Conference, 2010 May 31 - Juni 02, Graz, Austria. - 9783851251081 ; , s. 925-934
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Konferensbidrag (refereegranskat)abstract
- The acoustic emission that is detectable in the forming of complex thin part plates contains information about the quality of the pressed plates. The information can be used as process control and to filter out advanced thin plates with defects such as cracks. The article describes the results obtained in a try-out pressing process in special developed punch-die pairs with different pressing depths in a press at Alfa Laval in Lund. At the trials two module testing tools called SE30 and SE25 were used to create a different degree of formability by different surface enlargement in the same complex original design. Used sheet materials were stainless steel and two qualities of titanium. The used measuring system was based on a PC with AE-sensor of model 8152 from Kistler. The results of experiments show that it is possible to detect and distinguish the plates that fracture during the forming operation. For a large number of plates detectable signals from areas close to cracks with only local necking were also obtained. This local necking cannot or can hardly be detected by light-test or light detecting equipment. The left figure shows a metal sheet with fractures and the right figure describes measured acoustic emission as a function of time and the number of the details. In this example the first four plates are fractured and the last five plates are without any fractures. There are several differences between the two types of signals of acoustic emission. The signal that indicates cracking of the plate differs by a sudden high acoustic emission and also a slightly lower level before the crack formation is started. Before the fracture occurs the sheet metal is stretched out and the lower level of acoustic emission also indicates less movement of the sheet metal just before the time of fracture. The purpose of the conducted experiment was to find out whether the selected approach was appropriate. The obtained result shows unambiguously that the chosen approach is pertinent and that an AE-based monitoring system can be used as a process control system to ensure the quality of production of advanced thin plates in stainless steel and titanium. Information can be saved from the main forming operation and can be used to see trends both long and short term.
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| 38. |
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| 39. |
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| 40. |
- Gutnichenko, Oleksandr, et al.
(författare)
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Influence of cutting speed and tool wear on vibrations and process stability when turning Inconel 718 with PCBN tools
- 2014
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Ingår i: International Journal of Manufacturing Research. - 1750-0591. ; 9:2, s. 173-193
-
Tidskriftsartikel (refereegranskat)abstract
- Results of the study of cutting speed and tool wear influence on the vibrations and their nature during machining superalloy Inconel 718 with low cBN content (cBN-L) and binderless pcBN (bcBN) tools are presented. Cutting speed was varied from 2 to 14 m/sec while other cutting conditions were constant. The process evolution was studied with the wavelet transform of tool acceleration spectra. Behaviour of the dynamic system was found to vary with the cutting speed and the specifics of tool wear. It is shown that machining with bcBN tools was accompanied by appearance of significant vibration when cutting speed exceeded 5 m/sec, but the machining with cBN-L was characterised by the suppression of vibrations over the entire speed range. This was related to the difference of tool microgeometry development during the course of wear. The wear of bcBN tools, in contrast to cBN-L, was characterised by merger of crater and flank wear and formation of negative clearance angle. Such difference results in an increase of cutting forces 2-4 times as compared to cBN-L tools. Estimation of dynamic stability by 0-1 test confirmed the process instability when turning with bcBN tools at cutting speeds higher than 8 m/sec which concurs with chatter appearance.
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| 41. |
- Gutnichenko, Oleksandr, et al.
(författare)
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Machinability and process stability when turning Alloy 718 with standard and produced by selective laser sintering toolholders
- 2014
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Ingår i: [Host publication title missing].
-
Konferensbidrag (refereegranskat)abstract
- The paper presents the results of a comparative analysis of machinability and dynamic stability when turning a nickel-based superalloy with WRA tools in a conventional and prototype toolholders. The use of the prototype toolholder with a spatial structure is shown to significantly suppress vibrations during the machining and stabilize the process within the cutting speed range between 200 and 400 m/min. The above mentioned benefits are demonstrated to be owing to damping properties of the proposed toolholder.
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| 42. |
- Gutnichenko, Oleksandr, et al.
(författare)
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Self-generated vibrations and process stability when turning high chromium white cast iron with PCBN tools
- 2014
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Ingår i: Proceedings of the 6th Swedish Production Symposium.
-
Konferensbidrag (refereegranskat)abstract
- The dynamic instability and related problems when turning high chromium cast iron (HCCI) with two polycrystalline cubic boron nitride (PCBN) tools in wide range of cutting speeds and feed rates were studied in the article. The tool wear mechanisms and specifics for both tools as a main criterion of appearance of process instability were investigated. In spite of the chatter-like surface of machined workpieces it was shown the dynamic stability of process by two method ‘0-1 test’ and determination of maximum Lyapunov exponent. Taking into account the strong periodicity of process with several clear harmonics it was concluded that such process is related to self-resonant phenomena.
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| 43. |
- Hoseiny, Seyyed Mohammad Hamed, 1980, et al.
(författare)
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The influence of microstructure and mechanical properties on the machinability of martensitic and bainitic prehardened mould steels
- 2013
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Ingår i: International Journal of Materials Research. - : Walter de Gruyter GmbH. - 1862-5282 .- 2195-8556. ; 104:8, s. 748-761
-
Tidskriftsartikel (refereegranskat)abstract
- The machinability of two prehardened mould steels, one continuously-cooled and one quenched and tempered, is compared in terms of cutting temperature, cutting force and tool life. Both materials have a hardness of similar to 40 HRC which is a typical hardness for prehardened mould steels. The results of machinability tests are related to mechanical properties and microstructural features, and the material removal rate is estimated for the materials. The continuously-cooled steel with bainitic structure shows higher machinability and possesses superior impact toughness and ductility compared to the quenched and tempered steel with martensitic structure. These properties are very important for plastic mould steels. The continuously-cooled bainitic steel also has the advantage of not requiring any costly quenching and tempering processes in connection with its production.
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| 44. |
- Hörndahl, Mikael, et al.
(författare)
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EFFECTS OF COOLING RATE AND SILICON CONTENT ON AL/SICp MMC
- 2014
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Konferensbidrag (refereegranskat)abstract
- This paper reports the results of the study ofthe microstructural and mechanical properties ofmetal matrix composites (MMC) based on Al-Si matrix alloyandsilicon carbideparticulates. The scope of the studyis to investigate the effects of cooling rate and silicon content on the microstructure and the mechanical propertiesof MMC.Samples were cast in mouldsof different temperature in order to identifythe effects of the cooling rate while silicon content was varied from 7 to 12.5 %in the matrix material.The conclusion is that the cooling rate has little effect on the properties unless it is taken to the extreme and the effects of the silicon content is no more pronounced than for non-reinforced aluminium.
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| 45. |
- Johansson, Daniel, et al.
(författare)
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Tool Life and Wear Model in Metal Cutting, Part 1 - Influence of Varying Flank Wear Criterion on Colding's Tool Life Equation
- 2014
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Ingår i: Proceedings of the 6th Swedish Production Symposium.
-
Konferensbidrag (refereegranskat)abstract
- The tool life model formulated by Bertil Colding is limited to the use of a specified tool life criterion. The Colding equation describes the relationship between tool life, cutting speed and the equivalent chip thickness. The Colding equation is based on five constants which have unique values for each selected value of the tool life criterion. This paper investigates how these Colding constants can vary for different selected wear criteria.
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| 46. |
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| 47. |
- Jönsson, Mathias, et al.
(författare)
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Dynamic Manufacturing Costs - Describing the Dynamic Behavior of Downtimes from a Cost Perspective
- 2011
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Konferensbidrag (refereegranskat)abstract
- Downtimes in a manufacturing cell, line or individual machines are characterized by a stochastic behavior that their frequency and their duration display. A method is presented here for analyzing this dynamic behavior from a cost perspective. An important element of the method is statistical analysis of downtimes, including empirical distribution functions pertaining to downtimes of specific types. For demonstrating this, use is made here of genuine downtime data obtained from the Swedish company Alfa Laval.
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| 48. |
- Jönsson, Mathias, et al.
(författare)
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Relations between Volume Flexibility and Part Cost in Assembly Lines
- 2011
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Ingår i: Robotics and Computer-Integrated Manufacturing. - : Elsevier BV. - 0736-5845. ; 27, s. 669-673
-
Konferensbidrag (refereegranskat)abstract
- This paper presents a strategy for achieving volume flexibility in assembly lines, so that varying production demands can be met. The strategy involves providing assembly lines inherent cycle-time flexibility, through creating the possibility for operators to handle multiple work stations. A basic part-cost model serves as a basis for analyzing the cost effects of different staffing alternatives, its taking account of different performance parameters and numbers of operators. Use of the part-cost model is illustrated by analyzing two specific cases differing in the number of operators assigned to the assembly line, the operators being partly permanent and partly temporary workers. It is shown how the costs are affected by the production performance of the work force in question, temporary operators being expected to display a somewhat lower level of performance than permanent workers.
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| 49. |
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| 50. |
- Kirkhorn, Lanny, et al.
(författare)
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Improved tool wear properties in sheet metal forming using Carbide steel, a novel abrasion resistant cast material
- 2011
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Ingår i: Wear. - : Elsevier BV. - 0043-1648. ; 271:9-10, s. 1280-1287
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Tidskriftsartikel (refereegranskat)abstract
- Abstract in UndeterminedThis work presents a comparative study regarding wear behavior between a novel abrasion resistant cast iron, "Carbide Steel" and a number of conventional tool materials frequently used in the automotive industry. Carbide Steel is basically a high-Cr white cast iron heavily alloyed with cemented carbide. The high chromium content and additional alloying elements like WC. TiC or NbC results in a material containing a large portion of hard, wear-resistant carbides with a composition different from conventional white irons normally used in wear applications. Characteristic properties for the material are: superior as-cast properties, improved wear resistance and hardness. The as-cast hardness of Carbide Steel is comparative to hardened steel but depending on desirable properties of the wear part the alloying content can be varied within a wide range. An interesting aspect of the material is potential for sustainable manufacturing, due to the fact that the critical alloying elements are added in the form of recycled carbide inserts. The experimental work was carried out in a U-bending test equipment to simulate conditions in a stamping process. One type of sheet material was used and seven different conventional tool materials were evaluated. The selection of tool materials ranged from white cast irons to tool-steels and powder steels. The wear patterns were analyzed and expressed in percentages of reduction of weight of the test specimens, galling tendency and temperature variations during the experiments. All parameters were correlated to the number of strokes. The press force was measured and a friction coefficient was calculated. An important conclusion from the experimental work is that Carbide Steel has a significantly higher wear resistance compared to the other conventional tool materials evaluated. Galling is also significantly reduced when using Carbide Steel. The volume part of carbides and the relative size of the same play a significant role in the process leading to less galling and wear, when using Carbide Steel as a tool material. (C) 2011 Elsevier B.V. All rights reserved.
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