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Att äga framtiden : perspektiv på kommunal utveckling
- 2017
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Samlingsverk (redaktörskap) (övrigt vetenskapligt/konstnärligt)abstract
- centrum för kommunstrategiska studier (CKS) har i två decennier verkat som ett centrum för forskning och samverkan vid Linköpings universitet. CKS bedriver forskning med målet att fördjupa strategiskt relevant kunskap för en långsiktigt hållbar samhällsutveckling. Det gör vi genom akademiska fora och genom samverkan med kommuner och regioner. Genom det långsiktiga stödet från Linköpings universitet och kommunerna i Östergötland har kännedom om CKS verksamhet spridits och vi har kunnat erfara att vi utvecklats i riktning mot att etablera oss som ett nationellt kraftcentrum för strategisk kommunforskning.I samband med att CKS fyller tjugo år vill vi stanna upp och reflektera över den brytningstid som vi uppfattar att svenska kommuner befinner sig i. Det finns en offentlig diskussion och debatt om vilken väg kommunerna ska ta och den debatten vill vi delta i. Detta är bakgrunden till denna antologi, till vilken ett 30-tal författare som alla har stor erfarenhet av kommunala frågor har bjudits in. Forskare, experter, journalister, politiker och tjänstepersoner skriver alla om frågor som rör kommunernas framtid.Författarna behandlar olika frågor som i dag hamnar högt uppe på kommunernas agendor; förutsättningarna för lokal demokrati, spänningar mellan stad och land, global uppvärmning, lokal utveckling och näringslivsutveckling, migration och integration och effekterna av demografisk förändring. Genom att låta författarna diskutera och reflektera kring dessa frågor hoppas vi att den här antologin bidrar till en kunskapsbaserad, nyanserad och konstruktiv framtidsdiskussion. Vår förhoppning är att antologin ska komma att läsas av politiker, tjänstepersoner, experter, lärare, studenter, journalister och andra som är intresserade av de frågor som boken behandlar.TackDen här antologin har kunnat förverkligas genom stöd och arbetsinsatser från många. Här har Anna Valentinsson, kommunikatör vid CKS och Johan Ekfeldt, som språkgranskat texterna, varit helt centrala. Ett stort tack vill vi också rikta till våra långsiktiga finansiärer; Linköpings universitet, kommunerna i Östergötland och Region Östergötland.Norrköping 19 september 2017Martin Klinthäll, föreståndareBrita Hermelin, vetenskaplig ledare
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| 3. |
- Hägglund, Sören, 1956
(författare)
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Methods and Models for Cutting Data Optimization
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Traditional optimization of cutting processes refers to minimizing cost or minimizing time (minimumcost or maximum production rate). These criteria apply to the cutting speed via well-known equationsfor economic tool life and tool life for maximum production rate. Quite often speed is focused firstwhen after some suitable feed value is chosen. This is a poor strategy for several reasons.This thesis analyses and suggests suitable strategies, methods, algorithms and models for cuttingdata optimization with general guidelines as well as specific recommendations for some exemplifiedsituations. Effective procedures designed to avoid sub-optimizations and alternative models forminimizing the process costs, maximizing the production rate or minimizing the tool cost whileconsidering a desired cycle time (corresponding to actual demand of the produced part) are centralsubjects for the discussions.In a second phase, tool wear calibration allows for tool replacement coordination to minimizerelated costs, since planned occasions eliminates slack due to operator unattendance, and coordinatedtool replacements minimizes total replacement time.The procedures, methods and models for cutting data optimization discussed have also proven tomake significant cost reductions in several cases even when the process engineers involved in thesestudies generally have long experience and said to have optimized their processes continuously foryears.Although, the models presented in this thesis mainly refer to turning operations, these strategies areapplicable for turning, milling and holemaking processes and especially applicable for medium tolarge lot sizes in multi tool operations, cell balancing, transfer line balancing, etc.
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| 4. |
- Johansson, Daniel, et al.
(författare)
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Assessment of Commonly used Tool Life Models in Metal Cutting
- 2017
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Ingår i: Procedia Manufacturing. - : Elsevier BV. - 2351-9789. ; 11, s. 602-609
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Tidskriftsartikel (refereegranskat)abstract
- In this work, eleven different combinations of work piece materials and tool grades have been evaluated in wear test when turning with cemented carbide insert. The most commonly used tool life models such as the Taylor model, the Extended Taylor model, the Coromant Turning model version 1 and the Colding model have been tested on the data and their accuracy is presented. The well-known Taylor model proves to have a limited ability to reproduce the data. The most accurate model is the Colding model, with an average model error of approximately 4.0% and Woxén equivalent chip thickness proves to work well for all presented tool life models. This work also discusses the models ability to reproduce cutting data for finishing operations and possible limitations when extrapolating the models for smaller chip thicknesses.
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| 5. |
- Johansson, Daniel, et al.
(författare)
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Selecting Cutting Data Tests for Cutting Data Modeling Using the Colding Tool Life Model
- 2018
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Ingår i: Procedia CIRP. - : Elsevier BV. - 2212-8271. ; 72, s. 197-201
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Konferensbidrag (refereegranskat)abstract
- An analysis on selecting cutting speed, cutting feed and depth of cut when collecting data for the Colding Tool Life Model based on Woxen's Equivalent Chip Thickness was performed to achieve the lowest possible model error. All possible combinations of a large data set were evaluated with regard to model error. This work shows that an increase of ratio between the highest and lowest cutting speed, feed, depth of cut and tool life within the five included tool life tests increases the likelihood of an accurate model. Further, to ensure an accurate model, it is not enough to have a large ratio of one single parameter, but a large ratio in all parameters is needed. The paper also presents a suggestion on how to select the cutting data points, derived from the best performing tool life models. It is concluded that one should aim to have one pair of cutting data points with equal equivalent chip thickness while varying cutting speed and three more test points with different equivalent chip thickness.
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| 6. |
- Kantojärvi, Fredrik, et al.
(författare)
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Predicting tool life for side milling in C45 E using Colding and Taylor tool life models
- 2023
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Ingår i: Advances in Industrial and Manufacturing Engineering. - 2666-9129. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- This paper investigates the possibility of using empirical tool life models to predict tool life in a side milling application in a medium carbon steel, C 45E. To do this, an extensive dataset containing 46 data points with different machining parameters are produced. Four different empirical models: Taylor's equation, Colding's equation and Extended Taylor both using depth of cut and feed as well as an Extended Taylor using equivalent chip thickness has been considered. It is found that Colding's equation is best suited to predict the tool life for this application. Furthermore, this paper suggests a novel method to fit the experimental data to the empirical models. Based on the results from previously published papers it is shown that the proposed method performs equally or better to determine the model constants.
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| 8. |
- Schultheiss, Fredrik, et al.
(författare)
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Influence of the minimum chip thickness on the obtained surface roughness during turning operations
- 2014
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Ingår i: Procedia CIRP. - : Elsevier BV. - 2212-8271. ; 13, s. 67-71
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Konferensbidrag (refereegranskat)abstract
- Considerable efforts have been put into analyzing the obtained surface roughness during turning operations. However, knowledge is still lacking on how to model the arithmetic mean surface roughness Ra through using a general model applicable for all workpiece materials and process parameters. Further, the influence of the minimum chip thickness on the obtained surface roughness needs to be clarified. This article presents a new model for predicting the Ra surface roughness during turning operations. The model is based on physical and empirical knowledge of the turning process and has been experimentally validated through turning Al-SiCp MMC, cast iron, conventional- and stainless steels, as well as Ti6Al4V. The obtained results show great potentials with an average error of 6.7% even though errors as large as 16.6% were obtained for some cases.
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| 9. |
- Schultheiss, Fredrik, et al.
(författare)
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Modeling the cost of varying surface finish demands during longitudinal turning operations
- 2016
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Ingår i: International Journal of Advanced Manufacturing Technology. - : Springer Science and Business Media LLC. - 0268-3768 .- 1433-3015. ; 84:5, s. 1103-1114
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Tidskriftsartikel (refereegranskat)abstract
- Tolerances, including geometry, dimension, and surface roughness, are an important part of production where the desire to manufacture quality products have to be weighed against the increase of manufacturing costs. The desired tolerance will influence the choice of both manufacturing method and machine tool. Given that machining is an adequate production method, variation of the required tolerances will imply a variation of the part cost which needs to be taken into account during production planning. Thus, the term “tolerance cost” is introduced. The paper presents a model for evaluating the tolerance cost in respect to the surface roughness during longitudinal turning operations, enabling a better comparison between different production alternatives. Through knowledge of the required surface roughness, it is possible to estimate appropriate cutting conditions. Knowledge of the cutting conditions and the part geometry then makes it possible to calculate the cycle time, information which in turn may be used for calculating the corresponding part cost. Through using experimental data, it is proven that the required surface roughness has a significant influence on the attained manufacturing cost. For instance, while longitudinally turning AISI 4140, it was shown that an improvement of the surface roughness from Ra=3.2 μm to Ra=1.6 μm will entail an increase of the part cost by roughly 20 %. Similarly, a decrease of the required surface quality (larger Ra value) will imply a significantly reduced part cost.
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| 10. |
- Ståhl, Jan-Eric, et al.
(författare)
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Analytical Calculation of the Ra Surface Roughness during Turning
- 2012
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Ingår i: Proceedings of the 5th International Swedish Production Symposium. - 9789175197524 ; , s. 185-190
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Konferensbidrag (refereegranskat)abstract
- In this article an analytical equation for calculating the theoretical arithmetic mean surface roughness, Ra, in the case of turning using a tool with a circular nose radius is presented. The calculated Ra-values are verified by experimental results obtained from machining of 7 different workpiece materials. For all measuring series results were obtained that were either better or worse than the theoretically calculated values. The presented model describes an analytical equation for calculating the theoretical Ra-value and may be practically implemented in industry.
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