本文選題：單點漸進(jìn)成形　切入點：回彈　出處：《陜西科技大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：金屬板料單點漸進(jìn)成形是一種在數(shù)控機(jī)床上通過計算機(jī)控制成形工具頭運動的柔性制造技術(shù),在鈑金類件成形領(lǐng)域應(yīng)用前景廣闊。與傳統(tǒng)的金屬板料成形方式相比,單點漸進(jìn)成形省去了模具制造的過程,因此,這種成形方式具有成本低、生產(chǎn)周期短的特點,特別適用于那些生產(chǎn)批量不大的產(chǎn)品。但是在對這種成形方式的進(jìn)一步研究中,發(fā)現(xiàn)成形精度不足是制約單點漸進(jìn)成形技術(shù)發(fā)展的關(guān)鍵,按照目前的科技水平與工藝技術(shù)最高能達(dá)到的精度為±3mm,但在工業(yè)應(yīng)用領(lǐng)域要求成形件的精度為±0.2mm,這一精度要求嚴(yán)重制約了這項技術(shù)在先進(jìn)制造領(lǐng)域的推廣與應(yīng)用。因此,本文重點對成形過程中的回彈進(jìn)行了研究,因為回彈對成形件的精度影響最大,提出了減少回彈的方法;最后還對其它成形缺陷(厚度減薄、凹陷、破裂、壓痕)進(jìn)行了研究,提出了抑制這些成形缺陷的措施。本課題的研究內(nèi)容如下:(1)單點漸進(jìn)成形中理論問題的研究。主要分析了成形過程中的壁厚變化情況;同時對單點漸進(jìn)成形中的主應(yīng)力、主應(yīng)變進(jìn)行了分析,另外還對成形力進(jìn)行了理論分析;最后通過正交實驗對不同加工工藝參數(shù)條件下的成形力進(jìn)行了測量,得出了成形力與加工工藝參數(shù)的關(guān)系。(2)利用ABAQUS對漸進(jìn)成形過程進(jìn)行了數(shù)值模擬。分別模擬了成形角為30°、45°、60°,層間距為0.5mm、1.0mm、1.5mm,成形工具頭半徑為3mm、4mm、5mm條件下的應(yīng)力、應(yīng)變、位移。(3)采用實驗方法對單點漸進(jìn)成形中的回彈進(jìn)行了重點研究。首先,單獨研究了主軸轉(zhuǎn)速對回彈量的影響;然后,對不同形狀的成形件的回彈量進(jìn)行了研究,選取了三種典型的制件:外凸形、圓錐形、內(nèi)凸形;最后利用正交實驗對成形角、層間距、進(jìn)給速度、加工深度這四個因素對回彈量的影響進(jìn)行了研究,通過以上研究得出了這些因素對成形件回彈量的影響。(4)對漸進(jìn)成形過程中的其它一些成形缺陷進(jìn)行了研究。研究了成形角對成形件壁厚的影響;正交實驗研究了不同加工工藝參數(shù)條件下的最大凹陷值;另外還研究了板料表面的破裂、壓痕、金屬堆積現(xiàn)象,且提出了相應(yīng)的抑制這些缺陷的措施。(5)回彈現(xiàn)象是單點漸進(jìn)成形過程中一個不可避免的現(xiàn)象,減小回彈的方法很多。本文,主要研究了采用負(fù)補償方法來減小回彈,這為后期進(jìn)行相關(guān)研究提供了參考依據(jù)。
[Abstract]:Single point incremental forming of sheet metal is a kind of flexible manufacturing technology which can control the movement of forming tool head by computer on NC machine tool. It has a broad application prospect in sheet metal forming field. Single point incremental forming eliminates the process of die manufacturing, so it has the advantages of low cost and short production cycle, and is especially suitable for those products with small batch production. However, in the further study of this kind of forming method, It is found that the lack of forming precision is the key to the development of single-point incremental forming technology. According to the present level of science and technology, the maximum accuracy of the technology is 鹵3mm, but the precision of forming parts is 鹵0.2mm in the field of industrial application, which seriously restricts the popularization and application of this technology in the field of advanced manufacturing. In this paper, the springback in the forming process is studied, because the springback has the greatest influence on the precision of the forming parts, the method of reducing the springback is put forward, and the other forming defects (thickness thinning, depression, fracture, indentation) are also studied. The research contents of this paper are as follows: 1) the theoretical problems in single point progressive forming are studied. The variation of wall thickness in forming process and the principal stress in single point progressive forming are analyzed. The main strain is analyzed, and the forming force is analyzed theoretically. Finally, the forming force under different processing parameters is measured by orthogonal experiment. The relationship between forming force and processing parameters is obtained. The numerical simulation of progressive forming process is carried out by using ABAQUS. The stress and strain are simulated under the conditions of forming angle 30 擄45 擄60 擄, layer spacing 0.5 mm 1. 0 mm 1. 5 mm, and the radius of forming tool head 3 mm / 4 mm / 5 mm, respectively, when the forming angle is 30 擄/ 45 擄/ 60 擄, the layer spacing is 0. 5 mm / 1, and the radius of forming tool head is 3 mm / 4 mm / 5 mm. Displacement. 3) the springback of single point progressive forming is studied by experimental method. Firstly, the effect of spindle speed on springback is studied separately; then, the springback of different shapes of forming parts is studied. Three kinds of typical parts are selected: convex shape, conical shape and inner convex shape. Finally, the effects of four factors, such as forming angle, interval between layers, feed speed and machining depth, on springback are studied by orthogonal experiment. The influence of these factors on the springback of the forming parts is obtained. Some other forming defects in the process of progressive forming are studied. The influence of the forming angle on the wall thickness of the forming parts is studied. In addition, the fracture, indentation and metal accumulation on the surface of sheet metal were studied by orthogonal experiment under the conditions of different processing parameters. It is suggested that the springback phenomenon is an inevitable phenomenon in the process of single point progressive forming, and there are many methods to reduce the springback. In this paper, the negative compensation method is mainly used to reduce the springback. This provides a reference for the later research.
【學(xué)位授予單位】：陜西科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TG306

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本文編號：1558017