| 1. |
- Azarhoushang, Bahman, et al.
(författare)
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High-speed high-efficient grinding of CMCs with structured grinding wheels
- 2019
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Ingår i: International Journal of Abrasive Technology. - 1752-2641 .- 1752-265X. ; 9:1, s. 1-15
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Tidskriftsartikel (refereegranskat)abstract
- The implantation of ceramic matrix composites (CMCs) is limited due to their high machining costs. To overcome this problem, modified grinding wheels, one macro-structured by segmenting and another laser-structured were used. The grinding tests were carried out at different material removal rates and cutting speeds. The grinding forces, surface roughness, and induced residual stress were compared. The results showed that the wheel structuring resulted in a better performance of the grinding wheel. The grinding forces were respectively 30% and 20% lower in the case of segmented wheel and laser-structured wheel in comparison with the conventional grinding. In addition, the tensile residual stress was reduced as a negative output of the grinding process via structuring. A high-speed high-efficient grinding of CMCs without presence of surface damage was achieved by optimising the process parameters. The material removal rate could be elevated without changing the grinding forces with application of the structured wheel.
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| 2. |
- Azarhoushang, Bahman, et al.
(författare)
-
High-speed high-efficient grinding of CMCs with structured grinding wheels
- 2018
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Ingår i: ISAAT 2018 - 21st International Symposium on Advances in Abrasive Technology.
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Konferensbidrag (refereegranskat)abstract
- Ceramic Matrix Composites (CMCs) are counted as new materials which their implantation is limited due to their high machining costs as a result of high grinding forces and tool wear. To overcome mentioned problems, modified grinding wheels, one macro-structured by segmenting and another micro-structured (half lasered structured and half non-structured) were used in this study. The grinding tests were carried out at different material removal rates and cutting speeds. The grinding forces, generated surface roughness, and induced residual stress by means of grinding with the structured and non-structured wheels were compared. Reduction in the static cutting edges via wheel structuring resulted in a better performance of the grinding wheel through the reduction of rubbing and ploughing regimes. The grinding forces were respectively 30% and 20% lower in the case of segmented wheel and laser-structured wheel in comparison with the conventional grinding. In addition, the tensile residual stress can be reduced as a negative output of the grinding process via structuring. Moreover, a high-speed high-efficient grinding of CMCs without presence of surface damage was achieved by optimizing the process parameters. The material removal rate can be elevated without changing the grinding forces with application of the structured wheel.
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| 3. |
- Kadivar, Mohammadali, 1987, et al.
(författare)
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Laser-assisted micro-grinding of Si3N4
- 2019
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Ingår i: Precision Engineering. - : Elsevier BV. - 0141-6359. ; 60, s. 394-404
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Tidskriftsartikel (refereegranskat)abstract
- One of the main challenges in micro-machining of hard to cut materials is the accuracy of the machined part because of high grinding forces which cause tool deflection and rapid tool wear. Non-conventional machining processes have been developed as alternatives to conventional processes for optimizing the machining efficiency and achieving the desired tolerances. This paper addresses a novel Laser-Assisted Micro-Grinding (LAMG) process. For the first time, an ultra-short pulse laser is used to structure micro-grinding tools and a Si3N4 workpiece prior to the micro-grinding. The induced grinding forces and achieved surface roughness as well as the tool deflection and wear by the LAMG process are compared to the Conventional Micro-Grinding (CMG) process. Additionally, the ultra-short pulsed laser ablation process was simulated to find the proper laser parameters corresponding to the desired structure and laser-cut depth. The results proved an enhanced performance of LAMG process in micro-grinding of Si3N4. Using the simulation, the depth of laser cut prior to structuring could be predicted. Structuring, either the workpiece or the tool, significantly reduced the grinding forces. However, a rougher surface resulted via tool structuring. The grinding forces reduced up to almost 40% using 30% structured workpiece surfaces. Structuring the micro-tool (10% structuring) resulted in 60% reduction in the grinding forces with around 40% rougher surface. The accuracy of the part was highly improved by the laser structuring. The actual depth of cut using CMG was 30% lower than the nominal depth of cut. Utilizing LAMG the total nominal depth of cut was removed from material. The comparison between the topography of structured and non-structured tools indicated higher tool wear and shorter tool life with the non-structured tool.
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| 4. |
- Shamray, Sergey, et al.
(författare)
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Performance of micro-grinding pins with different bonding while micro-grinding Si3N4
- 2020
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Ingår i: International Journal of Abrasive Technology. - 1752-2641 .- 1752-265X. ; 10:1, s. 16-31
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Tidskriftsartikel (refereegranskat)abstract
- Selection of a grinding tool with proper specification and bond material is a major challenge in the field of micro/grinding process. In this fundamental study, four different types of diamond micro-grinding pins were used. The bond types were varied and their effects on the grinding forces and surface roughness were analysed. In the experimental study, the microtopography of the grinding tool, cutting speed and depth of cut were considered as input process parameters as well as the bond. The results revealed that forces and surface roughness are highly influenced by the tool topography. Using vitrified micro-grinding pin resulted in lower grinding forces (up to 40%) than other types. The tool wear increased with the material removal when using metal bonded grinding tool. Nevertheless, vitrified grinding tool was exposed to the self-sharpening - lowering the forces. The hybrid bond tool was the most stable tool during the grinding process - keeping the forces and surface roughness almost in the same order over the time, despite higher induced cutting forces.
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