本研究使用實驗室自行開發之五軸加工系統，應用於非平面雷射披覆成形，並藉由進給速率來控制披覆幾何形貌。非平面披覆過程中之NC加工碼為利用齊次轉換矩陣定義未知曲面工件座標與機械座標之關係來計算各軸移動量，並使用Mach3控制軟體完成披覆加工。

實驗中使用波長1064nm的低瓦數光纖雷射當作施加熱源進行微小的形貌披覆成形，首先對斜面平板進行披覆，探討不同基板角度對披覆形貌之影響，並以Fluent模擬粉末濃度場來加以分析。從斜板披覆實驗中得知披覆形貌會沿著雷射軸線堆積，會造成在曲面披覆當中披覆高度不均的現象，故在披覆實驗中噴嘴軸線會持續地與曲面保持垂直且等距。

從平面迴路披覆實驗中發現，當兩側路徑之切線夾角越小時兩端隆起程度越嚴重；再從平面、圓管與曲面披覆實驗當中發現，以等速的進給速率披覆時，越靠近兩端轉折點披覆高度會越高。

利用進給速率與披覆高度之關係對隆起的路徑給予不同的進給速率。經由速度修正後之平面與圓管披覆結果發現，當提升進給速率時能夠藉由降低粉末附著量來達到幾何形貌修正之目的。

A five-axis machining system was developed in this study. It was used in the non-planar laser cladding, which utilizes feed speed to control 3D cladding shape. During non-planar fabrication process, an NC code based on homogeneous transformation matrices defines the relationship between the substrate coordinate and machine coordinate for unknown work-piece surface. The Matlab with Mach3 control software were used to complete fabrication processing.

At first an inclined-surface plate was built with single-layer and single-track cladding, it can be found that the cladding shape varies with inclined angles. Fluent software was adopted to simulate the powder concentration field. From the inclined-surface plate’s cladding experiment, the cladding shape would accumulate along the laser beam center and cause uneven cladding height on the curved surface cladding; therefore the nozzle would be constantly kept vertical from the curved surface during cladding experiment.

In the planar loop cladding experiment, it can be found that the raising of the cladding height at the turning points on two sides at constant feed speed. The relationship of feed speed and cladding height was used. After speed control for flat surface and pipe cladding, it is able to reduce the powder adhesion amount in order to fix geometric shapes.

[1] Steen W.M., “Laser material processing”,Springer-Verlag,1991.
[2] 黃博詳, “同軸雷射披覆之斜板效應量測與分析”,國立成功大學機械工程研究所碩士論文,2000.
[3] Yang H., Shi J., “Study of laser precise drilling technology of ceramic material”, Proceedings of SPIE – The International Society for Optical Engineering, v5629, pp. 404-412, 2005.
[4] Nowotny S., “Laser Beam Build-Up Welding: Precision in Repair, Surface Cladding, and Direct 3D Metal Deposition”,Journal of thermal spray technology, v16(3),pp. 344-348,2007.
[5] Li J., “Calibration of a multiple axes 3-D laser scanning system consisting of robot, portable laser scanner and turntable”, Journal for Light and Electron Optics,v122(4),pp. 324-329,2011.
[6] Xu H., “Optimization of 3D laser cutting head orientation based on the minimum energy consumption”,Springer-Verlag,London,v74(9),pp. 1283-1291,2014.
[7] Zekovic S., “Numerical simulation and experimental investigation of gas–powder flow from radially symmetrical nozzles in laser-based direct metal deposition”, International Journal of Machine Tools & Manufacture,v47(1),pp. 112-123,2007.
[8] Liu H., “Numerical simulation of powder transport behavior in laser cladding with coaxial powder feeding”, Science China:Physics,Mechanics And Astronomy, v58(10),2015.
[9] 彭聖介, “ 雷射披覆修補模具之可行性研究”,國立台灣科技大學機械工程研究所碩士論文,1994.
[10] Picasso M., “A Simple but Realistic Model for Laser Cladding”, Metallurgical and Materials Transactions B,v25(2),pp. 281-291,1994.
[11] Liu J., “Study on cross-section clad profile in coaxial single-pass cladding with a low-power laser”, Optics & Laser Technology,v37(6),pp. 478-782,2005.
[12] Fathi A., “Geometry Control of the Deposited Layer in a Nonplanar Laser Cladding Process Using a Variable Structure Controller”, Journal of Manufacturing Science and Engineering,v130(3),2008.
[13] Colodrón P., “Performance Improvement of a Laser Cladding System through FPGA-Based Control”, 37th Annual Conference on IEEE Industrial Electronics Society,pp. 2814-2819,2011.
[14] Steen W. M., Mazumder J., “Laser material processing”,4th Edition, Springer, London, pp. 11-135, 2010.
[15] 張智星, “MATLAB程式設計與應用”,清蔚科技股份有限公司,2001.
[16] Asada H., “ROBOT ANALYSIS AND CONTROL”,John Wiley & Sons,1986.
[17] ANSYS FLUENT 14.0 User Guide,ANSYS Inc.,2011.
[18] Calleja A., “Feed rate calculation algorithm for the homogeneous material deposition of blisk blades by 5-axis laser cladding”,Journal of Advanced Manufacturing Technology,v74(9),pp. 1219-1228,2014.