3D砂模列印核心技術-壓電式噴墨頭是藉由控制驅動波型將噴墨液滴選擇性噴印至成型平台上，然而調整驅動波型參數會造成不同的液滴速度與墨量，這些液滴性質最終會影響列印物件的尺寸與完整性，因此本研究將探討波型參數、液滴性質與列印物件尺寸之關係，藉由控制壓電噴頭關鍵參數來提高砂模3D列印品質。
本研究使用高速攝影機搭建的觀墨系統來觀測液滴噴墨型態與適當噴墨參數，並建立3D砂模列印系統探討液滴速度與墨量對於砂模尺寸之關係。由實驗結果得到，波形驅動電壓越大，則液滴墨量越多，砂模尺寸誤差也會增加，且誤差是由第一層或最初幾層所造成的。另外，探討砂模強度發現，墨量越多、強度越好、成形性越好，但相對尺寸誤差越大，此條件難以同時達到平衡，因此本研究最後提供一個列印策略方案，將波型參數、液滴墨量、砂模尺寸誤差、砂模強度所得到之關係，透過軟體圖檔灰階設計與選擇，在最初幾層使用誤差較低之波型參數，而後幾層則增加墨量加強砂模強度，在300kgf強度需求下，還能將尺寸誤差降低至層厚10%以內。

The core technology of 3D sand mold printing is Piezoelectric inkjet head. The inkjet head selectively prints droplets onto the building platform by controlling the waveform. The waveform parameters influence the droplet properties which affect the dimension and quality of the printed object. Therefore, this study researches properties of piezo print head, including waveform parameters, droplet properties and the size of the printed object.
This study uses the high-speed camera to observe the ink-jet type and the appropriate ink-jet parameters and establish a 3D sand mold printing system to discuss the printing quality of influencing factors. As a result, the voltage is higher, the deviation value of printed object is bigger and the deviation is always caused by layer of printing beginning. In addition, the more inkjet quantity, the higher strength and the better formability it will be, but it causes the more deviation of dimension. So it’s hard to balance those influencing factors. Therefore, this study provides a printing strategy which is use gray level printing and the experimental results of testing. The strategy uses the lower deviation of waveform parameters at layer of beginning. After that, increase inkjet quantity to get the higher strength. Finally, this work achieves the deviation of dimension less than 10% under the 300kgf strength.

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