工件不等速運動下雷射照射之能量密度均勻化控制

Energy Density Uniformity Control of Laser Irradiation for Non-Isokinetic Moving of Work Piece

顏嘉谷(Chia-Ku Yen)

指導教授 ： 湯華興 ； 洪永銘

國立臺北科技大學/機電學院/機電整合研究所/碩士(2008年)

https://doi.org/10.6841/NTUT.2008.00464

摘要

本文針對XY-PLOTTER在加減速區域所衍生出雷射能量分佈不均勻的問題進行研究與改善，期望利用自製控制器進行工件在不等速運動下之雷射照射之能量密度均勻化控制，改善傳統控制器不等速運動下雷射照射之能量不均勻情況，進而得到較佳精度之工件。
為了改善雷射掃描時XY-PLOTTER在不等速運動下造成雷射照射之能量產生不均勻分佈之問題，使用TI 之TMS320F2812 晶片開發雙軸雷射能量控制器，其硬體方面利用VP2812EVM配合邏輯電路設計而成；軟體則是使用TI所提供之CCS開發軟體進行設計，模擬出觸發訊號與PWM訊號此兩種雷射機接受之訊號格式，並且由QEP電路進行移動距離之計數，判斷是否輸出PWM訊號。
本文為了了解自製控制器控制雷射於加減速區與等速區內能量之分佈，因此提出了新式雷射能量密度分析實驗法來進行自製控制器之實驗，由於壓克力材料對於熱的反應明顯，可觀察壓克力試片上之線寬線深的數據得知改善後之效果。
實驗可分為點陣掃描實驗與向量掃描實驗兩部份，由點陣掃描實驗結果顯示自製控制器的確明顯改善了能量分佈不均一之問題；由向量掃描實驗結果觀察出自製控制器完全改善傳統控制器在掃描輪廓圖形之轉角處能量集中之問題。

關鍵字

壓克力試片 ； 雷射能量密度 ； 線寬線深

並列摘要

The purpose of this paper is to study and to improve the non-uniform density distribution, which is derived from the acceleration or deceleration of the XY-PLOTTER. It is expected that under the condition that work piece moved with variable speed the laser energy density can be uniformly controlled by self-made controller. The non-uniform laser energy distribution of the traditional controller caused by a non-isokinetic movement of the work piece will be improved; then the precision of the work piece can be better than before.
For improving the non-uniform distribution of laser density when the XY-PLOTTER under non-isokinetic moving during laser scan, a bi-axial laser density controller is developed using TMS320F2812 chip of Texas Instrument. Its hardware is made up by VP2812EVM with logical circuit; its software is designed by CCS deployment software provided by Texas Instrument. Two signals, Tickle signal and PWM signal, which are acceptable by laser machine, are simulated. Furthermore, the counting of the moving distance is executed by QEP circuit and the results will be used to determine whether or not the PWM signal will be sent.
For completely understanding the density distribution in the acceleration zone and the deceleration zone and the constant speed zone formed by self-made controller, this paper propose a new laser density analysis method for testing self-made controller. The effect of improvement can be visualized by observing the line width and depth on the acrylic specimen caused by laser vaporization because the acrylic material is sensible to heat.
The experiment can be divided into two parts: dot matrix scanning and vector scanning. The result of dot matrix scanning shows the self-made controller can obviously improve the density distribution. The result of vector scanning shows the self-made controller can completely improve density concentration on corner during scanning the contour of the work piece by traditional controller.

並列關鍵字

acrylic specimen ； laser energy density ； line width ； line depth

參考文獻

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[12]Dolphin Wu，VP2812EVM技術手冊，台北：旺陽電企業股份有限公司，2005。

[1]H. H. Tang, “Method for rapid forming of a ceramic work piece,”. U.S. patent no. 6217816, 2001.

[6]Texas Instruments, TMS320F2812 Digital Signal Processors Data Manual. Literature Number: SPRS174L, December 2004.

[16]嚴孝全，陶瓷雷射燒結快速原型技術之研發，博士論文，國立台北科技大學機電科技研究所，2007。