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標題: | 超音波振動輔助平面磨削碳化鎢之樹脂砂輪選擇 Selection of the Resin Bond Grinding Wheel in Ultrasonic Assisted Surface Grinding of Tungsten Carbide |
作者: | Ping-Chen Hsieh 謝秉臻 |
指導教授: | 廖運炫(Yunn-Shiuan Liao) |
關鍵字: | 超音波輔助加工,平面磨削,碳化鎢,樹脂砂輪, ultrasonic assisted grinding,surface grinding,tugsten carbide,resin grinding wheel, |
出版年 : | 2019 |
學位: | 碩士 |
摘要: | 由前人研究指出超音波振動輔助磨削難切削材料時有明顯的效果,如在加工硬脆材料時可以減少磨削力使砂輪磨耗降低,並有效提升自銳能力;在加工延性的材料時能提升排屑能力使砂輪填塞速度降低,延長修整週期與刀具壽命,但很少探討到超音波輔助磨削的砂輪選擇,可能會與傳統磨削不同,由前人的研究與經驗可以知道在傳統磨削中,磨削軟的材料會使用結合度硬的砂輪,而磨削硬的材料則反之,會根據材料特性做選擇,但如果砂輪搭配了超音波振動輔助,去除材料的機制不同,在選擇砂輪的組成就會跟傳統磨削有差異。所以本研究選用業界常用的樹脂鑽石砂輪,探討顆粒集中度與結合劑硬度的砂輪對超音波振動輔助磨削的加工表現與砂輪磨耗情形,並驗證超音波輔助的磨削擁有較好的磨削性及砂輪壽命。
實驗結果顯示傳統磨削碳化鎢時主要的磨耗方式為破裂及磨損磨耗,破裂常會發生在加工初期顆粒不穩定時,隨著加工時間久了磨損磨耗容易形成磨耗平面。超音波輔助磨削的主要磨耗方式為部分破裂及磨損磨耗,部分破裂發生的頻率高,所以較不容易產生磨耗平面,代表自銳能力較佳。 砂輪選擇方面不管是傳統磨削或是超音波磨削都須使用集中度高的砂輪,磨削性較好,而傳統磨削需搭配結合度較軟的砂輪,但超音波磨削需搭配結合度硬的砂輪。比較了兩種加工搭配適合的砂輪組成的磨削性,發現超音波輔助磨削的修整週期比傳統磨削了多38%,代表超音波磨削可以移除更多的材料而不需要做修整,提升加工效率。 The assistance of ultrasonic vibration on the difficult-to-cut materials has been proved very effective in grinding process. For example, when grinding brittle materials, the grinding force can be reduced to lower the wear, and the self-sharpening ablity of the grinding wheel can be effectively improved;When grinding ductile materials, chip adhesion can be reduced substantially, and the dressing cycle of the grinding wheel can be extended. However, many researches have not explored the selection of the grinding wheel for ultrasonic assisted grinding, which may be different from the traditional grinding. In conventional grinding process, grinding soft materials will use a hard-bonding grinding wheel, while grinding hard materials will use a soft-bonding grinding wheel. So which kind of grinding wheel selected is based on the material characteristics, but if grinding is equipped with ultrasonic vibration assistance,it will be different because of the difference of material removal mechanism. Therefore, my research will use resin grinding wheels which are the most common in industries. And I will investigate the grinding performance and wear of ultrasonic vibration assisted grinding with different abrasive concentration and bond hardness and verify that ultrasonic assisted grinding has better Grinding and grinding wheel life. Experimental results show that the main wear mode of conventional grinding of tungsten carbide is macro fracture and attritious wear. The macro fracture often occurs when grains are unstable at the beginning of processing. And attritious wear usually becomes a wear plane after long processing times. Nevertheless, the main wear mode of ultrasonic assisted grinding is partial(micro) fracture and attritious wear. The frequency of partial fracture is high, so grains are less possible to become wear surfaces, which means better self-sharpening ability. Regarding to the selection of grinding wheel, whether it is traditional grinding or ultrasonic assisted grinding, it is necessary to use a grinding wheel with high concentration. And according to the grade of the grinding wheel bond, traditional grinding needs to use the grinding wheel with softer combination, but the ultrasonic grinding needs to use the grinding wheel with harder combination. Comparing the grinding method with two respective suitable grinding wheels, it is found that the dressing cycle of ultrasonic assisted grinding is 38% times more than the traditional grinding, which means that ultrasonic grinding can remove more materials without dressing and increase grinding efficiency. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/74339 |
DOI: | 10.6342/NTU201901308 |
全文授權: | 有償授權 |
顯示於系所單位: | 機械工程學系 |
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