CNC 工具機產效暨與節能同步優化設計與空刀率之智能監測研究

Study of Syncronous Optimization of Machining Efficiency and Energy Consumption and Idle Machining Monitoring

李軍逸(CHUN-YI LEE)

指導教授 ： 王世明

中原大學/工學院/機械工程研究所/碩士(2017年)

https://doi.org/10.6840/cycu201700110

摘要

馬達為CNC工具機加工時主要耗電的元件之一，一般廠商最常用的三軸CNC工具機其主要耗電馬達包含一個主軸馬達和三個伺服軸馬達，其他如自動換刀馬達或排屑馬達因相對功率或使用時間較低，因此其對機台總體耗電的影響也較輕。若欲分析機台加工條件與耗電量之間的關係，可以分析主軸馬達和伺服軸馬達為主。在同步考慮機台耗電成本與加工效率下，應該根據馬達耗電特性選擇最佳的切削參數組合，求得加工效率與耗電成本的優化組合。首先瞭解有切削負載對各馬達的性能與耗電關係的影響，進而建立加工效率與耗能的同步優化設計演算法，並結合人機介面的設計，便成為一個可輔助加工製造廠進行產線優化的系統，協助工程師找出兼具“能源效益和產能效益”的加工參數優化組合。本研究之產效與節能同步優化系統以CNC工具機為對象，對主軸馬達及三軸伺服馬達轉速與耗電的關係和進給速度與耗電的關係進行分析，並建立藕合關係模型，再據以建立加工節能綜效分析演算法，再將演算法植入所設計的人機介面完成一協同優化設計系統。研究最後在合作廠商瀧澤公司進行實機驗證，實驗結果顯示有無切削的耗電確實有明顯差別，且各軸馬達在某些加工進給下的耗電量相對較低，此可能為機台結構上的各種特性(EX.移動軌道的摩擦阻力)所導致的綜合結果，優化設計系統則可根據此現象將加工參數進行修改，以達到產效與節能同步優化的效果。
加工過程中的空刀時間會影響加工效率及機台有效稼率，極小化空刀時間亦是加工參數優化的一環。研究中之空刀率監測功能以CNC工具機為對象，以線上主軸電流變化來判斷是否做有效切削，同時也以當下執行NC程式來作為輔助判斷，避免其他情形造成主軸負載變化而導致系統誤判。研究以C#撰寫的空刀監控模組針對加工中NC程式的G01、G02、G03進行監測，在人機介面上顯示有效加工與無效加工時間分析結果。研究最後在研究室的CNC進行實機驗證，實驗結果顯示監測的誤差範圍在一秒內，可作為優化加工路徑與減少空刀時間的參考依據。

關鍵字

CNC工具機 ； 產效 ； 節能 ； 優化 ； 空刀率 ； 稼動率

並列摘要

Motor is the main energy consumption in the CNC tool machine. Generally, the energy consumption of 3-axis CNC machine including spindle motor, servo motor of XYZ axis, auto-tool change motor, and chip removal motor. However, the auto-tool change motor and chip removal motor are not significantly influenced the total energy consumption because is not frequently be used. Spindle motor and servo motor can be used to analyze the relationship between machining process and energy consumption. Both energy consumption and machining efficiency are simultaneously considered. To obtain optimal machining efficiency and energy consumption cost, the optimal combination of cutting parameter according to the motor energy consumption characteristics must be selected. Firstly, understanding the relationship between cutting load on the motor performance and energy consumption. Thus, establish algorithms for simultaneous processing efficiency and energy consumption optimization. Furthermore, human machine interface was designed, and finally a machining optimization assisted system that help engineer to identify “energy and productivity efficiency” optimum machining parameter was created. In this study, simultaneous optimization of productivity efficiency and energy saving for CNC machine tool was investigated. Relationship between spindle rpm, feed rate, and energy consumption were analyzed, and then analysis modelling was created. Special algorithm was used to establish energy saving analysis, and included in the human machine interface as well as in the system. Experiment was carry out to verify the proposed system. The experiment result showed a significant energy consumption between without cutting and with cutting. The servo motor under certain feedrate exhibits lower energy consumption. The may be related to characteristics of machine structure (i.e. friction of rail). This phenomenon can be used to modify machining parameter in order to achieve optimum production efficiency and energy saving.
Air cutting during machining process will affect the machining efficiency and utilization rate. Minimizing of air cutting time is also one of the optimization parameter. Investigation of air cutting time is one of the objective in this study. Online spindle current change was used to determine whether the cutter is in process of cutting or air cutting. At the same time, NC program was also used to help decide it, and also to avoid wrong diagnosis of spindle current change that affected by other circumstances. The online air cutting monitoring module that built using C# language program is use to monitor G01, G02, G03 of NC program. The analysis result of effective machining and ineffective
machining were displayed on human machine interface. Experimental and verification of the system were carried out. The experimental results showed that the error range of the monitoring is within one second. This can be used as a basis for optimizing machining path and minimizing air cutting time.

並列關鍵字

CNC machine tools ； production efficiency ； energy saving ； optimization ； air cutting time ； utilization rate

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