【摘要】：隨著我國現(xiàn)代化制造行業(yè)的高速發(fā)展,汽車已經(jīng)普遍融入到日常生活當(dāng)中,汽車的銷售和生產(chǎn)數(shù)量日益增長,因此對汽車覆蓋件模具的表面質(zhì)量要求越來越嚴(yán)格,相應(yīng)的數(shù)控加工技術(shù)受到了廣泛地重視。汽車覆蓋件多數(shù)為自由曲面,考慮到球頭刀加工自由曲面的局限性,環(huán)形刀的應(yīng)用越來越廣泛,但環(huán)形刀加工曲面時,時常發(fā)生干涉的現(xiàn)象,因此,如何規(guī)劃刀具軌跡來避免干涉現(xiàn)象的發(fā)生,是數(shù)控編程時應(yīng)主要考慮的問題�；谏鲜鰡栴},本文針對兩種自由曲面進(jìn)行加工參數(shù)優(yōu)化后,根據(jù)所得最優(yōu)參數(shù)的數(shù)學(xué)模型,進(jìn)行工件姿態(tài)的調(diào)整及刀具軌跡的重新規(guī)劃。首先,對環(huán)形刀加工汽車覆蓋件模具進(jìn)行行距優(yōu)化研究,分別對4種代表性型面建立了行距與刀具幾何參數(shù)、殘留高度之間的數(shù)學(xué)模型;針對兩種常用的型面建立了基于刀位點的行距數(shù)學(xué)模型;基于所建立的數(shù)學(xué)模型,分別對4種型面進(jìn)行了銑削加工實驗,驗證了模型的準(zhǔn)確性。其次,針對環(huán)形刀加工凹曲面汽車覆蓋件時產(chǎn)生的欠切干涉現(xiàn)象進(jìn)行了研究。分析了刀觸點處刀具與曲面的微分幾何關(guān)系,根據(jù)所建立的行距數(shù)學(xué)模型,得出了刀軸的最優(yōu)傾角;對凹曲面進(jìn)行了軌跡仿真及加工效率的分析,得出了最優(yōu)走刀方向后,確定了坐標(biāo)系之間的轉(zhuǎn)換關(guān)系,從而將工件姿態(tài)調(diào)整到最優(yōu);針對凹曲面型面,分別用傳統(tǒng)方法和本文方法進(jìn)行了對比實驗,從而驗證了本文方法的正確性。最后,針對環(huán)形刀加工凸曲面汽車覆蓋件時產(chǎn)生的過切干涉現(xiàn)象進(jìn)行了研究。通過分析干涉產(chǎn)生的原因,確定了消除干涉的方法;進(jìn)行了凸曲面加工實驗,確定干涉發(fā)生點的位置;將刀具調(diào)整到最優(yōu)姿態(tài)后,應(yīng)用軌跡密化法重新規(guī)劃刀具軌跡,達(dá)到消除干涉的目的。針對凸曲面型面,分別用傳統(tǒng)方法和本文方法進(jìn)行了對比實驗,從而驗證了本文方法的可行性。
[Abstract]:With the rapid development of the modern manufacturing industry in China, the automobile has been integrated into the daily life, and the sales and production quantity of the automobile is increasing day by day. Therefore, the surface quality requirements of the automobile panel die are becoming more and more strict. The corresponding NC machining technology has been paid more and more attention. The automobile covering parts are mostly free-form surfaces. Considering the limitation of ball-head knife in machining free-form surfaces, the application of ring-shaped knives is more and more extensive. However, interference often occurs when machining surfaces with ring-shaped knives, so, How to plan tool path to avoid interference phenomenon is the main problem to be considered in NC programming. Based on the above problems, after optimizing the machining parameters of two kinds of free-form surfaces, according to the mathematical model of the optimal parameters, the adjustment of workpiece attitude and the re-planning of tool path are carried out. Firstly, the optimization of line spacing for automobile panel die with ring cutter is studied. The mathematical models of line spacing, tool geometry parameters and residual height are established respectively for four typical profile surfaces. A line spacing mathematical model based on tool point is established for two kinds of common profile surfaces, and milling experiments are carried out to verify the accuracy of the model based on the established mathematical models. Secondly, the undercutting interference caused by ring cutter machining concave surface automobile panel is studied. The differential geometric relationship between tool and surface at tool contact point is analyzed. According to the mathematical model of line spacing established, the optimal inclination angle of tool axis is obtained. The trajectory simulation and machining efficiency analysis of concave surface are carried out. After the optimal direction of cutting tool is obtained, the transformation relationship between coordinate systems is determined, and the attitude of workpiece is adjusted to the optimum. Compared with the traditional method and the method in this paper, the correctness of the method is verified by comparing the concave surface with the traditional method and the method in this paper. Finally, the phenomenon of over-cut interference in the machining of convex surface automobile panel with ring cutter is studied. Through the analysis of the causes of interference, the method of eliminating interference is determined, and the machining experiment of convex surface is carried out to determine the position of interference point. After the tool is adjusted to the optimal attitude, the tool path is re-programmed by the method of path densification to eliminate the interference. Compared with the traditional method and the method in this paper, the feasibility of this method is verified by comparing the convexity surface with the traditional method and the method in this paper.
【學(xué)位授予單位】：哈爾濱理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2016
【分類號】：TG659

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