| 1. |
- Hägglund, Sören, 1956
(author)
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Methods and Models for Cutting Data Optimization
- 2013
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Doctoral thesis (other academic/artistic)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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| 2. |
- Schultheiss, Fredrik, et al.
(author)
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Influence of the minimum chip thickness on the obtained surface roughness during turning operations
- 2014
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In: Procedia CIRP. - : Elsevier BV. - 2212-8271. ; 13, s. 67-71
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Conference paper (peer-reviewed)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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| 3. |
- Ståhl, Jan-Eric, et al.
(author)
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Analytical Calculation of the Ra Surface Roughness during Turning
- 2012
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In: Proceedings of the 5th International Swedish Production Symposium. - 9789175197524 ; , s. 185-190
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Conference paper (peer-reviewed)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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| 4. |
- Ståhl, Jan-Eric, et al.
(author)
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Tolerance Cost in Relation to Surface Finish during Longitudinal Turning Operations
- 2014
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In: Proceedings of the 6th Swedish Production Symposium.
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Conference paper (peer-reviewed)abstract
- Tolerances are an important part of production where the desire to produce quality products have to be weighed against the increased production costs. The desired tolerance will influence the choice of both production method as well as the machine used. Given that machining is an adequate production method, variation of the required surface roughness will imply a variation of the part cost which needs to be taken into account during production planning. This paper presents a method for evaluating the tolerance cost in regards to surface roughness during longitudinal turning operations, thus enabling a better comparison between different production situations.
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