鈷含量對碳化鎢磨削特性及表面性狀影響之研究

Investigation of the effect of cobalt concentration on the grindability of cemented carbide

彭揚景(Yang-Ching Peng)

指導教授 ： 趙崇禮

淡江大學/工學院/機械與機電工程學系碩士班/碩士(2012年)

https://doi.org/10.6846/TKU.2012.00251

摘要

玻璃模造製程（GMP）在大量生產高精度光學元件，如球面及非球面玻璃透鏡及自由曲面光學元件，是非常具有前景的一項技術。然而，只有極少數的材料可以承受在玻璃模造成形時，產生的化學反應、機械應力及高溫等影響，而這類的模具材料大多是難加工的材料。致使要將這類的材料加工到次微米等級的形狀精度及奈米等級的表面粗糙度是相當困難且耗費成本。而在可選擇的材料為數不多的情形下，碳化鎢(WC)是目前業界最常應用於玻璃模造的模具材料之一。碳化鎢，是由碳化鎢與結合劑鈷燒結成的材料，為碳化鎢顆粒及鈷結合成的複合材料。鈷含量對於碳化鎢的機械性質扮演著很重要的角色。因此本研究的目的為探討不同鈷含量對於碳化鎢的磨削特性之影響。而本研究所選用的加工參數為主軸轉速、切削深度與進給，了解此加工條件對加工後表面所造成的影響。研究發現，較低的鈷含量其碳化鎢有著較高的硬度值及較佳的表面粗糙度(Ra)。在本研究中，鈷含量0%至3%的碳化鎢其表面粗糙度值可達到5nm，其結果優於鈷含量6%至13%的10nm。

關鍵字

磨削加工 ； 碳化鎢 ； 表面粗糙度

並列摘要

Glass molding process (GMP) is regarded as a very promising technique for mass producing high precision optical components such as spherical/aspheric glass lenses and free-form optics. However, only a handful of materials can sustain the chemical reaction, mechanical stress and temperature involved in the glass molding process and almost all of these mold materials are classified as hard-to-machine materials. This makes the machining of these materials to sub-micrometer form accuracy and nanometer surface finish a rather tough and expensive task. Amongst those handful choices, tungsten carbide (WC) is by far the most commonly used mold material in GMP industry. WC, also known as sintered/cemented WC with cobalt (Co) binder, is a metal matrix composite of WC particles and Co matrix. Cobalt concentration plays an important role in shaping mechanical properties of the obtained WC/Co materials. This research aimed to investigate the effect of Co concentration on the grindability of WC/Co materials. Efforts have been made to correlate grinding parameters such as spindle speed, cut depth and feed to the obtained surfaces. It is found that, despite of higher hardness values, better surface finish can be achieved on WC/Co specimen of lower Co concentration. In the present study, surface roughness (Ra) values better than 5nm and 10nm were obtained on WC/Co specimens of 0~3% and 6~13% Co concentrations respectively.

並列關鍵字

Grinding ； WC ； Surface roughness

參考文獻

【32】 范偉華, “精密加工硬脆材料之表面性狀研究”, 淡江大學機械與機電工程學系博士論文, 民國一百年

【28】 廖怜怡, “單點車削碳化鎢之研究”, 台灣大學機械工程學系碩士論文, 民國一百年

【5】 J.W. Gardener, H.T. Hingle, “From Instrμmentation to Nanotechnology”, Gordon and Breach Science Publishers, USA, (1991).

【6】 J. Gurland, “New Scientific Approaches to Development of Tool Materials”, Int. Mater. Rev., 33, No.3, 151 (1988)

【8】 R.R. Reeber, K. Wang, “Thermophysical Properties of a-Tungsten Carbide”, J. Am. Ceram. Soc., 82, No. 1, 129 (1999)