| 摘要: | 放電加工發展至今已超過半個世紀，而其所加工的材料亦不計其數，卻鮮少出現以放電加工多晶矽材料的相關文獻。本文將利用線切割放電加工法(WEDM)加工多晶矽材料，並探討各項加工參數對於加工進給速率、加工擴槽寬及表面粗糙度的影響，冀望能在多晶矽的線切割放電技術上有所突破。 實驗結果顯示，脈衝時間越長或開路電壓越大，加工進給速率越快、加工溝槽越寬、表面越粗糙；休止時間正好完全相反。至線張力方面，雖然增加線張力可以改善加工溝槽的寬度，但是加工進給速率會隨著線張力增強而降低，也因此表面粗糙度有變差的趨勢。至於其他加工參數的影響，沖水流率越大對加工進給速率、加工溝槽寬及表面粗糙度均有改善的效果。至於送線速度方面，增加送線速度可小幅度改善加工進給速率、加工溝槽寬，而對表面粗糙度的影響則相當有限。 第二部份的實驗結果亦顯示使用雙脈衝電源加工多晶矽材料，確實可有效改善放電延遲的現象並增加放電頻率，進而提升加工效率。經實驗證明線切割放電加工法確實可應用在多晶矽材料的切割上，日後將此製程技術應用於太陽能電池相關產業上，將具有很大的競爭力。 Electrical discharge machining (EDM) has been developed for over half a century, and there have been numerous materials machined by means of this technology. However, little research is conducted on poly-silicon. The current study investigated the effects of operation parameters on feedrate, machining groove width, and surface roughness, utilizing the technology of WEDM to process poly-silicon, in hopes of having a breakthrough in the technology of WEDM on poly-silicon. The results showed that the longer on-time or the larger the open-voltage was, the faster the feedrate was, the wider the machining groove width was, and the coarser the surface roughness was. The off-time suggested a contrast effect. Moreover, increasing the wire tension might modify the machining groove width, but might lower the feedrate, revealing a tendency of worsening the surface roughness. As for other factors causing effects on the manufacturing process, a larger flush flow rate, helped amend the feedrate, the machining groove width, and surface roughness while wire speed could only partially improve the feedrate, the machining groove width and had limited impact on the surface roughness. The results from the second part of the experiment also indicated that processing poly-silicon by means of double-pulse power supply could actually modify the phenomenon of ignition delay and increase the discharge frequency, promoting the machining efficiency. The present study successfully showed that WEDM can be applied to poly-silicon wafers slicing. This manufacturing process is believed to be competitive if used in industries related to solar cell. |
