摘要
台灣的工具機產業是全球第三大出口國，緊追在德國、日本之後，在工具機產業中，滑動機構是最常見的運動機構，因此如果能夠掌握滑動面摩擦特性勢必可以改善工具機的機械性能。滑動機構的典型應用於重負荷高精度之硬軌工具機的進給系統，而硬軌在使用上通常會產生很大的摩擦力及磨耗，為了降低摩擦力和磨耗量，會在接觸面上施加鏟花以改善其磨潤效果。現階段的鏟花加工面臨許多問題，目前皆是以經驗傳承的人工的方式進行，除了技術人口老化造成人力不足外，亦無法固定鏟花加工品質，此外，對於鏟花加工較少學理探討，缺乏有系統對鏟花面紋理的分析與研究，造成國內工具機產業無法提高精度和可靠度的瓶頸。本研究預期開發一套雷射鏟花製程，有系統的探討鏟花加工參數對於摩擦係數和磨耗量的
影響。
本研究針對工具機結構最常使用之FC300灰口鑄鐵作討探，首先以目前鏟花產業用於分析紋理之指標作為設計表面紋理的依據，利用雷射咬花加工表面紋理，接著利用迴轉式摩擦試驗機擷取摩擦係數並討論不同紋理之間的差異，並加大摩擦試驗機的負載在試片上產生磨耗，最後利用彩色三維雷射顯微鏡量測磨耗深度。
本研究結果顯示在具表面紋理試片隨著速度增加摩擦係數下降，符合stribeck曲線，而未加工表面紋理試片隨著實驗時間增加摩擦係數上升，且產生磨耗量大於具表面紋理試片。紋理密度方面，在密度較高PPI為100時，因高低點交會處較密集摩擦阻力大，但高點分布較均勻整體受力較為平均產生較少的磨耗量。本實驗證實表面紋理可以有效提高滑動機構之磨潤效果。透過本研究初步掌握鏟花加工參數對磨潤的影響，可提供目前人工鏟花加工參數選擇上的參考，並期望能取代部分鏟花工作，提升鏟花效能。
關鍵詞：雷射加工、雷射鏟花、摩擦試驗、磨耗分析
Abstract
Taiwan is the third biggest exporter country
of Machine Tool Industry in the world, only next behind Germany
and Japan. In the machine tool industry, a sliding mechanism is
one of the most commonly provided in mechanical devices.
Therefore, we can improve the mechanical properties of the
machine if the sliding surface friction characteristics can be
predicted. A general application is the guide rail used in the
feeding system for heavy-duty high-precision machine tools.
These rails are prone to get wear and produce great friction. In
order to reduce these circumstances, the contact surfaces of
guide rail will should be scraped appropriately. However, there
are many problems in scaping process. First of all, scraping
process is usually manual by proficient worker, and mainly
depend on their experience inheritance. Rather than enhancing
the quality of scraping process, scraping process is time
consuming. Hence, we expect to develop a laser scraping process
to explore the impact of the processing parameters on the
coefficient of friction and wear.
In this thesis, we focus on cast iron widely
used in machine tools. Firstly, we design the surface texture
based on the current scraping industry and utilize the laser
surface texture processing to treat the surface of
workpiece.Furthermore, we obtain the friction coefficient from
the rotating tribometer, and discuss the differences with
different patterns. Finally, we measure the depth of wear by a
color 3D laser microscope.
It is noted that the friction coefficient of
the specimen with surface texture is reduced when processing
speed increased. However, the specimen without surface texture
is completely opposite. For texture density, there is a lot of
friction resistance in high density, but with less wear. The
results also showed that the sliding mechanisms with surface
texture have superior lubrication effect. In this study, we can
understand the cause of tribological properties on scraping
process parameters, and expect to replace part of the manual
scraping to improve scraping the performance.
Keywords: Laser processing, Laser scraping,
Friction testing, Wear analysis. |
