應用在陶瓷快速原型之 雷射能量均勻控制

A Uniform Laser Energy Density Control for the Ceramic Laser Sintering Rapid Prototyping

黃崇京(Chong-Jing Huang)

指導教授 ： 曾百由

國立臺北科技大學/機電學院/機電整合研究所/碩士(2012年)

摘要

本研究目的為控制雷射能量均勻分佈在陶瓷雷射燒結(Ceramic Laser Sintering, CLS)快速原型上的加工。以CO2雷射進行向量輪廓掃描時，若CO2雷射機為固定能量功率激發時，掃描至路徑上的加減速區域或轉角處，會因為機構運動速度變化，而造成雷射能量分佈不均勻；且CO2雷射機激發能量不穩定，進而影響到陶瓷工件精度。
因此本研究為了改善前人方法缺失與解決雷射能量不穩定的問題，先量測雷射機輸出功率量測訊號，再利用嵌入式控制器讀取此訊號，進行閉迴路控制，使雷射機能量達到穩定。再以雷射能量密度的觀念，以實驗方式找出機台掃描速度與雷射燒結效果的關係，利用嵌入式控制器去讀取CLS快速原型機台上馬達編碼器的資訊，再依機台掃描速度與雷射功率的關係去調變雷射控制訊號，以達成雷射能量燒結均勻分佈的目的和改善前人方法的缺點。
在實驗部分，實際在壓克力材料和陶瓷材料上進行雷射掃描，並利用高倍率金相顯微鏡觀察量測雷射能量在壓克力材料和陶瓷材料上的燒結變化情形(線寬、線深)有無達到能量均勻一致目的，實驗證實本研究雷射能量均勻控制器不僅能控制燒結線寬，也能達到能量分佈均勻的效果。

關鍵字

快速成型 ； CO2雷射 ； DSP

並列摘要

This study has focused on CO2 laser energy control for the processing of Ceramic Laser Sintering rapid prototyping which sinters ceramic powders into a solid object. If the triggering frequency of laser machine is fixed in the two dimensional contour laser scanning, the laser energy distribution will be uneven at the turning corners or in acceleration/deceleration regimes caused by the variations of velocity. The quality of sintering and finishing will be affected by this non-uniform energy distribution.
To improve the achievements in the earlier researches, as well as to stabilize the laser energy control, this project has implemented energy sensor and control circuits to first measure the laser energy and then feedback this signal to the controller. By using feedback control, this laser energy could be controlled within a reasonable range. With the concept of laser energy density, the relationship of scanning speed and CLS has been investigated. By using the position encoder feedback and derived speed of scanning, the laser power is modulated with Power Control Unit (PCU) to make uniform laser energy density and sintering, thus drawbacks in the earlier studies are then improved.
In the experiments of this project, controlled laser processing is applied on the machining of acrylic and ceramic powder samples for observations on the dimensions of the engravings by using high resolution microscope. The results have shown promising and feasible laser energy control algorithm to make uniform laser sintering quality.

並列關鍵字

Rapid prototype ； CO2 laser machine ； DSP.

參考文獻

[7] 林政毅，雷射燒結變質層層厚控制技術，碩士論文，國立台北科技大學製造科技研究所，台北、台灣，2006。

[8] 顏嘉谷，工件不等速運動下雷射照射之能量密度均勻化控制，碩士論文，國立台北科技大學機電整合研究所，台北、台灣，2008。

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