龍門型立式加工中心機結構特性與拓樸最佳化之研究

Study on Structure Characteristics and Topology Optimization for a Vertical Machining-Center with Gantry Type

吳育禎(Yu-Jen Wu)

指導教授 ： 林盛勇

國立虎尾科技大學/工程學院/機械與電腦輔助工程系碩士班/碩士(2013年)

摘要

近年來能源的危機及產業間的競爭越來越劇烈，如何減少能源損失、降低生產成本及提升產品的品質，以滿足消費者的需求，已成為一個非常重要的課題。業界為了追求高強度性能、高生產效能及低經濟成本，一般會朝著高速化與輕量化的目標發展，但衍生而來的是結構強度不足的問題，因此必須針對此結構特性作進一步的瞭解，以避免振動問題的產生。在高速的運動下，為了減少質量的問題，必須將移動部件輕量化，同時又不能降低結構的剛性，避免結構產生破壞。因此工具機之加工精度良窳與否，其設計考量，在於結構是否具有足夠的動態剛性、負載剛性、較高的自然頻率、重量輕及良好的抗振能力。如何設計出符合上述條件的工具機結構及開發週期縮短、成本降低，已成為現今發展工具機所面臨的問題，因此結構最佳化設計技術也日趨重要。
本論文主要是以龍門型立式加工中心機為載具，首先利用有限元素分析軟體對整機結構進行數值模態分析，求得模態參數。接著對加工中心機結構進行實驗模態分析，探討加工中心機結構模態特性，並與數值模分析結果相互搭配驗證，建立起一等效的有限元素模型，進一步瞭解結構模態特性以避免結構在使用上發生共振，導致結構發生損壞。並利用拓樸最佳化分析軟體對結構各部件進行最佳化，使結構剛性提升並達到結構輕量化之目的以減少材料的使用，進而降低生產成本的支出。本研究結果顯示，在主軸迴轉頻率範圍內共計有三個模態容易引發結構共振頻率，因此在加工時應避免使用這些頻率的轉速。將靜態分析之結果應用於拓樸最佳化，可看出各部件結構之最大應力、最大變形量及部件重量均有降低的趨勢。透過本實驗、分析與診斷流程之建立，能夠提前預知加工中心機結構之缺陷，並能夠提供業界做為加工中心機系統設計上的改善與參考，對未來擬開發新型加工中心機於設計上亦具有相當的參考性。

關鍵字

龍門型立式加工中心機 ； 有限元素分析 ； 模態參數 ； 剛性 ； 拓樸最佳化

並列摘要

In recent years, the energy crisis and the competition between the enterprises are getting more intense. It has been an important topic of how to minimize the energy loss, reduce the production cost and upgrade the product quality and satisfy the demands of consumers. In general, to pursue the high strength quality, high production efficiency and lower economic cost, the enterprise will develop toward the target of high speed and low weight, yet the structural strength problem will be derived afterward, therefore, it must be understood further on these structural characteristics to avoid the occurrence of the vibration problems. Under higher movement, in order to reduce the weight problem, moving parts are asked to be light, and to avoid destroying the structure, the stiffness of the structure can not be lowered down at the same time, Therefore, the processing precision is good or bad, the designing consideration depends on whether the structure has enough dynamic stiffness, load stiffness, higher natural frequency, light weight and good anti-vibration ability. How to design the tool machine mechanism to meet conditions stated above and shorten the developing period and reduce the cost, those topics have become the questions that the enterprises need to confront them, thus, the optimization of designing technology is more important day after day.
This thesis takes mainly the vertical machining-center with gantry type, At first, employing the finite element analysis software proceed the numerical model analysis of the whole machine structure and find the model parameters. Then, proceed the experimental model analysis, discuss the characteristics of the processing center machine structure model, collocate and verify each other with the result of numerical model analysis and implement an equivalent finite element model. The further step is to understand the characteristic of structure model to avoid the occurrence of resonance on the structure, thus, leading to the damage of the structure. Also, applying topology optimization analysis software to proceed the optimization of every part of the structure, thus, upgrading the structure stiffness to reach the goal of light weight structure (reducing the material usage) and the lower expense of production cost. The result of the study reveals that there are 3 models in the range of spindle rotation frequency are induced the structural resonance frequency easily; it must be avoided to use the speed of these frequencies during the processing. Applying the results of static analysis on the topology optimization, it can be found that there are lowering tendency of the maximum stress, maximum deformation and part weight for every part structure. Through this experiment, analysis and implementation of the diagnosis flow chart, it enables to predict the defects of the machining center structure in advance, and enables to provide to enterprises as improvement and references when designing the machining center machine system. It is also very referable to develop the new designing of the machining center machine in the future.

並列關鍵字

Vertical Machining-Center with Gantry Type ； Finite element analysis ； Modal parameter ； Stiffness ； Topology optimization

參考文獻

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