| 1. |
- Andersson, Carin, et al.
(författare)
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Bandsawing. Part I: cutting force model including effects of positional errors, tool dynamics and wear
- 2000
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Ingår i: International Journal of Machine Tools & Manufacture. - 0890-6955. ; 41:2, s. 227-236
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Tidskriftsartikel (refereegranskat)abstract
- This article presents a mechanical cutting force model for bandsawing. The model describes the variation in cutting force between individual teeth and relates it to initial positional errors, tool dynamics and edge wear. Bandsawing is a multi-tooth cutting process, and the terminology of the cutting action is discussed and compared with other cutting processes. It will also be shown that the setting pattern and the preset feed govern the cutting data.
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| 2. |
- Andersson, Carin, et al.
(författare)
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Bandsawing. Part II: detecting positional errors, tool dynamics and wear by cutting force measurement
- 2000
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Ingår i: International Journal of Machine Tools & Manufacture. - 0890-6955. ; 41:2, s. 237-253
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Tidskriftsartikel (refereegranskat)abstract
- This article presents a method for measuring individual cutting forces during bandsawing. Methods for detecting errors in cutting edge positions, tool dynamics during machining and geometry changes due to wear have also been developed. The experimental studies that we have conducted show that the cutting forces vary during the tool engagement. These variations in force were then quantified using a previously developed cutting force model for multi-tooth cutting processes including effects of positional errors, tool dynamics and wear.
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| 3. |
- Nilsson, Anders, et al.
(författare)
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Zinc-alloys as tool materials in short-run sheet-metal forming processes - Experimental analysis of three different zinc-alloys
- 2002
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Ingår i: Journal of Materials Processing Technology. - 0924-0136. ; 125-126, s. 806-813
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Tidskriftsartikel (refereegranskat)abstract
- In recent years, there has been an increasing demand from manufacturing industries for new tool materials such as more wear resistant zinc-alloys, with optimised characteristics regarding short-run sheet-metal parts production. Research on zinc-alloys wear resistance has been performed by a lot of research groups. However, it is very difficult to compare the wear resistance of these materials due to the fact that the investigations have been carried out with conventional methods, such as pin-on-disc or block-on-ring tests. In this paper wear resistance has been evaluated for three different zinc-alloys with different primary phase as die-tool material in forming process equipment. The method used has been the U-bending process, in which the conditions are realistic due to the complex varying load and strain during the forming process. The primary phase in ACuZinc5 is a F-phase, which is harder and stronger than the primary phases in Norzak2 and ZA27. ACuZinc5 is almost nine times more abrasive resistant and Norzak2 is 1.8 times more abrasive resistant than ZA27. An other conclusion that can be drawn is the importance of using a methodology during the experimental work that has realistic conditions, both for the tool material and sheet-metal.
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| 4. |
- Zhou, Jinming, et al.
(författare)
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Effect of chamfer angle on wear of PCBN cutting tool
- 2003
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Ingår i: International Journal of Machine Tools & Manufacture. - 0890-6955. ; 43:3, s. 301-305
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Tidskriftsartikel (refereegranskat)abstract
- In precision hard turning, a remaining problem is to minimise tool wear to maintain the accuracy of geometry and surface finish. Tool wear not only directly reduces the part geometry accuracy but also increases cutting forces drastically. The change in the cutting forces also causes instability in the tool motion, which results in more inaccuracy. PCBN cutting tools are often used in hard turning. However, they are still relatively expensive compared to ordinary carbide cutting tools. In order to attain sufficiently high production rates at minimum cost, increase of knowledge on cutting tool geometry is necessary. This article presents a study of the effect of chamfer angle on tool wear of PCBN cutting tool in the super finishing hard turning. The correlation between cutting force, tool wear and tool life were investigated. The optimised chamfer angle for PCBN cutting tool is suggested. Finally, the distribution of stresses and maximum principal stress working on the tool edge were calculated with the use of finite element method. (C) 2002 Elsevier Science Ltd. All rights reserved.
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| 5. |
- Zhou, Jinming, et al.
(författare)
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Identification of cutting errors in precision hard turning process
- 2004
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Ingår i: Journal of Materials Processing Technology. - : Elsevier BV. - 0924-0136. ; 153-154, s. 746-750
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Tidskriftsartikel (refereegranskat)abstract
- During past 10 years, the availability of polycrystalline cubic boron nitride (PCBN) tools has made application of hard turning increase remarkably in a range of industrial areas, especially in automotive, roller bearing and hydraulic industry. Among the applications of CBN cutting tools, precision hard turning attracts great interests since its environmentally friendly and flexibility, which ultimately has potential to replace grinding. Using today’s high precision hard turning with high precision motion control, high static and dynamic stiffness and thermal stability CNC machine, the dimensional accuracy can reach IT5. However, this accuracy still does not meet the demands from most industries. In addition, precision hard turning has been hampered by uncertainties with respect to part quality and process reliability. Many factors affect the machining accuracy and process stability. The presented work analysis the possible error driver factor and error sources in a precision hard turning and the strategy of on-line compensation of the dimensional errors in the process, based on the monitoring of tool wear and prediction of thermal expansion. Test results indicate that within the certain range of flank wear the developed method can improve the geometric accuracy significantly.
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| 6. |
- Zhou, Jinming, et al.
(författare)
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Machining characteristics of novel-abrasion resistant iron
- 2004
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Ingår i: Journal of Materials Processing Technology. - : Elsevier BV. - 0924-0136. ; 153-154, s. 751-757
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Tidskriftsartikel (refereegranskat)abstract
- Novel-abrasion resistant iron (N-AR iron) is a new cast iron, which basically is a high-Cr white cast iron alloyed with cemented carbide (13 wt.%). The cemented carbide can be either powder from cemented carbide tool or use of recycled carbide tool. The characteristic properties for the material are the castability and its superior wear resistance which means that the N-AR iron has a high potential as tool material in many industrial applications, for example, in sheet metal forming processes and other tools exposed for abrasive wear. In presented paper, machining characteristics or machinability of N-AR iron was investigated in order to select suitable tool material and cutting parameters for this material with respect to achievable surface roughness (Rz), dimensional accuracy, material removal rate and tool wear rate. Cutting forces and chip shape of the N-AR iron material were also examined during the investigation to clarify the reason why the tool rate is so high in the machining.
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| 7. |
- Zhou, Jinming, et al.
(författare)
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The monitoring of flank wear on the CBN tool in the hard turning process
- 2003
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Ingår i: International Journal of Advanced Manufacturing Technology. - : Springer Science and Business Media LLC. - 0268-3768 .- 1433-3015. ; 22:9-10, s. 697-702
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Tidskriftsartikel (refereegranskat)abstract
- In precision hard turning, tool flank wear is one of the major factors contributing to the geometric error and thermal damage in a machined workpiece. Tool wear not only directly reduces the part geometry accuracy but also increases the cutting forces drastically. The change in cutting forces causes instability in the tool motion, and in turn, more inaccuracy. There are demands for reliably monitoring the progress of tool wear during a machining process to provide information for both correction of geometric errors and to guarantee the surface integrity of the workpiece. A new method for tool wear monitoring in precision hard turning is presented in this paper. The flank wear of a CBN tool is monitored by feature parameters extracted from the measured passive force, by the use of a force dynamometer. The feature parameters include the passive force level, the frequency energy and the accumulated cutting time. An ANN model was used to integrate these feature parameters in order to obtain more reliable and robust flank wear monitoring. Finally, the results from validation tests indicate that the developed monitoring system is robust and consistent for tool wear monitoring in precision hard turning.
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