3D有限元素法模擬選擇性雷射燒結製程

Numerical Analysis of Selected Laser Sintering by 3D Finite Element Method

顏郡毅(Chun-Yi Yen)

指導教授 ： 李有璋

中原大學/工學院/機械工程研究所/碩士(2016年)

https://doi.org/10.6840/cycu201600791

摘要

本文在微觀尺度下以數值分析法模擬最密堆積之選擇性雷射燒結製程的溫度分佈，其中假設雷射能量為一高斯分佈函數並沿著一特定方向以特定速度移動來加熱粉末，在考慮粉末的非線性熱傳、熱對流與熱輻射的情況下探討光斑大小、速度所帶來的影響。
在這其中確定了當光斑半徑小於或等於粉末半徑時只有沿著雷射移動路徑下的粉末是可以達到燒結溫度並燒結成一實體，且明白光斑大小與溫差成反比，光斑愈大溫差愈小反之則愈大，故如何在最小的光斑大小中達到一最均勻溫度是本文的重點；從結果得知在製程前期，因粉末接近室溫且雷射移動速度相對於粉末大小過於快速導致在製程前期粉末無法得到足夠的能量來進行燒結，是故以改變速度的方式來使得製程中的能量分佈不均來達到完整燒結與均溫的效果。

關鍵字

有限元素法 ； 選擇性雷射燒結

並列摘要

In this paper, transient temperature for the selected sintering laser process with the most-packed particle at micro-scale was simulated by numerical analysis. The numerical model assuming that a Gaussian laser beam move along a given path with a particular speed to heat the sintering particles with considering the nonlinear heat conduction, convention and radiation and investigate the influence of the laser beam size and the laser moving speed on the temperature distribution.
The numerical results show once the beam size radius is equal to or less than the particle radius, only the particle which along the laser moving path can reach the sintering temperature, meanwhile, the temperature gradient is inversely proportional to the beam size hard to reach a uniform temperature distribution with smaller beam size. The initial particle temperature is closed to the room temperature and the laser moving speed is too fast to provide enough energy to reach the sintering temperature lead to lower temperature distribution, therefore, changing the laser scanning speed during the sintering process with increasing scanning speed can achieve more uniform temperature and also reach the sintering temperature.

並列關鍵字

Numerical Analysis ； Selected Laser Sintering

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