臺灣博碩士論文加值系統

近年噴頭噴印技術隨著積層製造的再次崛起，而衍生出許多不同於紙本印刷的新興應用；由於壓電噴頭的快速噴墨與高精準度等優勢，適合應用於快速打樣與各式直接製造等方法，進而成為在3D列印中材料噴印與黏著劑噴塗成型技術上的主流應用。隨著噴印效率的改善與大型工件的需求，多頭噴印的應用亦更加廣泛；然而，噴頭噴印狀態及多頭對位校正則將是攸關噴印尺寸精確度與品質的關鍵之一。鑑此，本研究藉由開發一影像視覺式演算系統，針對機台噴頭進行離線的平面自動對位校正與噴孔檢測；在噴印初始前產生合宜噴頭配置的對位參數，以改善人力校正所需的時間與對位誤差，進而降低於立體疊層的位置誤差。列印對位圖形作為對位參考，經外部掃描器取像；再透過視覺演算方法擷取特徵，以利計算噴頭對位偏差，並產生噴印系統所需的設定參數。本研究將多噴頭對位方法進行簡化；相對人工對位，不僅降低對位誤差，節省所需的工作時間。並提供具多噴頭之3D列印系統使用者一簡便且快速的噴頭對位整合應用。

Since additive manufacturing technique has raised again in recent years, it has opened a new era for document printing technology as well as modeling and tooling industries by using printheads or nozzles. However, the condition of the printhead is directly yield the finishing quality of the printed part. With the increasing demand of larger scale parts and concerns of printing efficiency, using plurality of printheads for a wider printable area is necessary. Moreover, the major obstacle of printhead arrays is that the correlated stitching and misalignment between multiple printheads will not satisfied the target image dimension. Therefore, the purpose of this thesis attempts to help a printing system to align the printheads and monitor head conditions rapidly. In this thesis, a vision system for multiple printheads alignment and inspection was developed. Machine vision computation was conducted in order to manipulate the alignment configurations for a better image quality. This proposed vision inspection procedure was manipulated by a scanner and vision processing techniques as an offline system. Result of this thesis showed an adequate alignment setting of multiple printheads by image processing algorithms. Compared with manual alignment, the proposed system not only reduces the tedious and complicated processes but also saves lots of time. This thesis may be of importance in explaining the printhead alignment configuration, as well as in providing the printing system and users with a better understanding of multiple printhead operation for a 3D printing system.

摘要 III
ABSTRACT IV
ACKNOWLEDGEMENT V
TABLE OF CONTENT VI
LIST OF FIGURES VIII
LIST OF TABLES X
CHAPTER 1 INTRODUCTION 1
1.1 Background 1
1.2 Research Objective 2
1.1 Framework of this Thesis 3
CHAPTER 2 BACKGROUND AND LITERATURE REVIEW 4
2.1 Literature Review 4
2.2 Inkjet Technology with Additive Manufacturing 6
2.2.1 Material Jetting 6
2.2.2 Binder Jetting 7
2.3 Overview on Inkjet Technology 9
2.3.1 Piezoelectric Printhead 11
2.3.2 Printhead Principles 12
2.3.3 Application of Printhead Array 15
2.3.4 Printing Driver System 16
2.4 Computer Vision and Image Processing 17
2.4.1 Thresholding Processing 17
2.4.2 Edge Detection 18
2.4.3 Contour Representation 19
2.4.4 Polygonal Approximation 20
CHAPTER 3 SYSTEM INTEGRATION AND METHOD 22
3.1 Printing System 22
3.1.1 System Framework 22
3.1.2 Motion System 25
3.1.3 Print Head System 25
3.1.4 Material Supply System 27
3.2 Vision Inspection System 29
3.2.1 System Architecture 30
3.2.2 Image Acquisition 31
3.2.3 Image Processing 31
3.2.4 Multiple Head Inspection 33
3.2.4.1 Nozzle Inspection 33
3.2.4.2 Head Alignment 33
CHAPTER 4 EXPERIMENTAL RESULTS 37
4.1 Printhead Inspection 37
4.2 Printhead Alignment 41
4.2.1 Image Processed Result 41
4.2.2 Actual Printing Test 45
CHAPTER 5 CONCLUSIONS AND FUTURE WORKS 49
5.1 Conclusions 49
5.2 Future Works 51
REFERENCES 52

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