臺灣博碩士論文加值系統

隨著製造業不斷朝向先進製造系統邁進，生產過程對於精度、效率和可靠性的要求也越來越高。在這種產業轉型中，工具機的結構完整性成為機床的重要指標，五軸同動 CNC 加工中心扮演非常關鍵的角色。振動會直接影響加工精度，而保持結構完整性對於實現先進製造所需的高精度至關重要。實際上任何微小的變形都可能轉化為生產誤差，從而阻礙先進製造所追求的效率和可靠性。本文對五軸加工中心的振動特性和變形模式進行了全面的研究，目標在優化其結構完整性，並最終促進更有效率和更可靠的先進製造環境。本研究採用了一種雙重方法。首先進行有限元素分析 (FEA) 模擬，以確定機床結構的固有頻率和模態形狀，再進行實驗模態分析 (EMA) 來驗證有限元素分析模型的準確性，以確保其符合實際狀況。通過 EMA 和 FEA 獲得的固有頻率之間的百分比差異分別為第一、二和三個模態的 11.77%、17.73% 和 12.08%。繼振動分析之後，本研究探討了空間定位對加工中心性能的影響。對主軸箱進行了詳細的空間分析，以了解工件再不同位置如何影響機床的剛度和固有頻率。發現尤其是在處理大型工件時，特定位置會導致剛度和固有頻率降低，這可能會降低加工精度。這種綜合分析提供了主軸箱在 27 個不同空間位置的變形和頻率變化的詳細分析。在不同模式下，可以從主軸運動的測量百分比變化中發現其明顯差異。例如，第一模態的差異範圍為 -4.92% 到 2.26%，而第二模態的差異範圍為 -5.46% 到 8.10%。其他模式也觀察到類似的趨勢，凸顯了工具機複雜的動態行為。為了解決這一弱點，本論文使用有限元素分析進行設計優化過程的範例。給出床台的原始模型、透過數值模擬模型進行設計優化的結果以及主軸箱的重新設計模型配置。此類優化的主要是為了實現兩個目標：減輕重量和提高結構的固有頻率。這些發現表明進一步研究的潛力，可以將這種優化方法擴展到其他關鍵部件，從而可能進一步提高工具機結構的整體完整性和效率。

The relentless march towards advanced manufacturing systems in manufacturing demands ever-increasing precision, efficiency, and reliability within production processes. Within this paradigm shift, the structural integrity of machine tools takes center stage, with 5-axis CNC machining centers playing a particularly critical role. Vibrations directly impact machining accuracy, and maintaining structural integrity is paramount for achieving the high-precision requirements of advanced manufacturing. In essence, any minute deformation can translate into production errors, hindering the very efficiency and reliability that advanced manufacturing strives to achieve. This thesis presents a comprehensive investigation into the vibration characteristics and deformation patterns of a 5-axis machining center, aiming to optimize its structural integrity and ultimately contribute to a more efficient and reliable advanced manufacturing environment. The study employed a two-fold approach. First, finite element analysis (FEA) simulations were conducted to establish the natural frequencies and mode shapes of the machine structure. Subsequently, experimental modal analysis (EMA) validated the accuracy of the FEA model, ensuring its real-world applicability. The percentage differences between the natural frequencies obtained from EMA and FEA were 11.77%, 17.73%, and 12.08% for the first, second, and third mode shapes, respectively. Following the vibrational analysis, the study explored the impact of spatial positioning on the machining center's performance. A detailed spatial analysis of the spindle housing was conducted to understand how different positions relative to the workpiece affect the machine's rigidity and natural frequencies. The key finding indicated that specific positions could lead to decreased rigidity and lower natural frequencies, potentially reducing machining accuracy, especially when handling larger workpieces. This combined analysis provided detailed insights into the deformation and frequency variations of the spindle housing across 27 distinct spatial positions. Significant variations were observed in the measured percentage changes in spindle movement across different modes. For instance, variations in the first mode ranged from -4.92% to 2.26%, while the second mode ranged from -5.46% to 8.10%. Similar trends were noted in other modes, highlighting the complex dynamic behavior of the machine. To address this vulnerability, an illustrative example of a design optimization process using FEA was presented. The results showcased the original model, design-optimized result through a numerical simulation model, and the redesigned model configurations of the spindle housing. The main goal for this type of optimization aims to achieve dual objectives: weight reduction and an increase in the structure's natural frequency. These findings suggest the potential for further research that expands this optimization approach to other critical components, potentially leading to even greater improvements in overall structural integrity and efficiency of the machine structure.

摘要 ......i
Abstract ......iii
Acknowledgments ......v
Table of Contents ......vi
List of Tables ......ix
List of Figures ......x
Chapter 1 Introduction ......1
1.1 Overview Research ......1
1.2 Industry 4.0 vs Industry 5.0: A Shift towards Human-Machine Collaboration ......3
1.3 Literature Review ......4
1.4 Context and purpose of the work and structure of the thesis ......8
Chapter 2 Related Theory ......11
2.1 Fundamentals of Machining Dynamics ......11
2.1.1 Machining Process Dynamics ......12
2.1.2 Diagnostics and Modelling ......13
2.1.3 Applications of Machining Processes ......15
2.1.3.1 Structural Mechanics ......15
2.1.3.2 Structural Dynamics and Vibration Analysis ......15
2.2 Fundamentals of Structural Analysis ......16
2.2.1 Types of Structures and Loads ......16
2.3 Finite Element Analysis (FEA) Principles ......19
2.3.1 FEA Methodology ......22
2.4 Modal Analysis Theory ......24
2.4.1 Excitation and Response Measurement ......25
2.4.2 System Identification ......25
2.4.3 Model Validation ......26
Chapter 3 Numerical Modeling using ANSYS Workbench ......28
3.1 Introduction to ANSYS Workbench ......28
3.2 Boundary Conditions ......30
3.2.1 Material Selection and Mesh generation ......33
3.3 Static Structural Analysis ......38
3.4 Harmonic Analysis ......39
3.5 Transient Analysis ......45
Chapter 4 Experimetal Investigation of the UGE 630 ......47
4.1 Frequency excitation of the machining center ......47
4.1.1 Natural Frequencies and Mode shape characteristics ......48
4.2 Experimental Modal Analysis ......49
4.2.1 Data Acquisition and Analysis ......50
4.2.2 Impact Hammer Testing ......54
4.2.3 ME’Scope (FRF Response and Modal Validation) ......55
4.2.3.1 Sensor Points ......55
4.2.4 Data Analysis and Signal Processing ......56
4.3 Evaluation of Modal Assurance Criteria (MAC) using Impact Hammer Testing ......64
Chapter 5 Mechanical Structure Evaluation of UGE-630 ......70
5.1 Establishment of machining accuracy ......70
5.2 Spatial Positioning of the UGE-630 Spindle Housing ......72
5.2.1 Static structural deformation analysis of the UGE 630 due to self-weight ......74
5.2.1 Modal Frequency Trends ......80
Chapter 6 Conclusions and Future Prospects ......84
6.1 Conclusions ......84
6.2 Future Prospects ......86
6.2.1 Topology Optimization for Targeted Improvement ......86
6.2.1.1 Sample Optimization: The Spindle Housing ......86
References ......89
Extended abstract ......93

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