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1、<p> 出處:Journal of Materials Processing Technology</p><p> Volume 201, Issues 1–3, 26 May 2008, Pages 247–251</p><p> 10th International Conference on Advances in Materials and Processin
2、g Technologies — AMPT 2007</p><p> 題目:筆記本頂蓋的鎂合金板材沖壓模具設(shè)計</p><p> ?蔡恒光,廖浩欽,陳復(fù)國</p><p><b> 摘要:</b></p><p> 在本文章中,對LZ91鎂鋰合金板材在室溫下制造筆記本頂蓋時的沖壓工藝進行了檢
3、查,同時使用了實驗方法和有限元分析。四步工序沖壓工藝的開發(fā),以消在沖壓頂蓋的工藝的情況下產(chǎn)生裂縫和起皺缺陷。為了驗證有限元分析,進行實際操作沖壓工藝與使用0.6毫米厚的LZ91的空白。厚度分布在不同地點之間的實驗數(shù)據(jù)和有限元計算結(jié)果吻合良好,證實了有限元分析的準(zhǔn)確性和效率。 LZ91板材在室溫成形性能優(yōu)越,也表明目前的筆記本頂蓋的成功制造研究。適合的四步操作過程本身操作程序數(shù)量少,比在目前的實踐要求,形成在筆記本鉸鏈的有效途徑。這也印證
4、了在制造筆記本蓋的情況下,可以用LZ91鎂合金板材的沖壓工藝生產(chǎn)。它提供了一個在電子行業(yè)替代鎂合金的應(yīng)用。</p><p><b> 關(guān)鍵字</b></p><p> ?筆記本電腦情況下;LZ91鎂鋰合金板材;多工序沖壓;成形性</p><p><b> 介紹</b></p><p> 在E
5、MI中由于重量輕,性能良好,在電子行業(yè)鎂合金已被廣泛用于結(jié)構(gòu)部件,如手機和筆記本電腦。雖然現(xiàn)行的鎂合金產(chǎn)品制造過程一直壓鑄,鎂合金板材的沖壓行業(yè),因為其有競爭力的生產(chǎn)力和有效的薄壁結(jié)構(gòu)構(gòu)件生產(chǎn)性能已制定的利益。由于它的六角形密堆積(HCP的形成)晶體結(jié)構(gòu)([陳等,2003]和[陳和黃,2003]),即使它需要高溫,常用沖壓工藝中鎂合金(鋁3%,鋅1%)已在目前的形成過程中應(yīng)用。最近,鎂,鋰(LZ)合金也已研制成功,以提高鎂合金的室溫成形
6、性。鎂合金的延展性,可以改善鋰此外,開發(fā)形成體心立方(BCC)晶體結(jié)構(gòu)([Takuda等人。,1999],[Takuda等。,1999]和[Drozd等,2004])。</p><p> 在本研究中,一個筆記本頂蓋使用LZ表的情況下的沖壓工藝進行了檢查。筆記本頂蓋的兩個鉸鏈的形成,如圖1所示(a和b),是由于在沖壓過程中最困難的操作之間的法蘭和圖中顯示在小角落半徑小的距離。 如圖1(c)。造成這種幾何復(fù)雜圓角半
7、徑的一個戲劇性的變化時,鉸鏈法蘭太接近筆記本的邊緣,這很容易造成周圍的鉸鏈法蘭斷裂缺損,并要求多操作,,克服這一問題。在本研究中,LZ鎂合金板的成形性能和最佳的多工序沖壓工藝開發(fā),以減少同時使用的實驗方法和有限元分析的操作程序。</p><p> 圖1 在筆記本頂蓋的鉸鏈法蘭 (a)鉸鏈,(b)頂蓋情況和(c)法蘭。</p><p> 2。鎂合金板材的力學(xué)性能</p>&
8、lt;p> 在室溫下進行拉伸試驗,比較其機械性能,在高溫下對AZ31張鎂鋰合金板材LZ61(鋰6%,鋅1%),LZ91,LZ101。圖2(a)顯示LZ表在室溫和那些對AZ31張在室溫和200°C的應(yīng)力應(yīng)變關(guān)系據(jù)悉,應(yīng)力 - 應(yīng)變曲線趨于增加鋰的含量較低。圖(2)也顯示,LZ91板材在室溫和AZ31鎂板在200°C是彼此接近。 LZ101板材在室溫下具有更延性比LZ91和AZ31在200°C由于鋰的成
9、本是非常昂貴,而不是LZ101板材LZ91板材,可被視為一個合適的LZ鎂合金板材在室溫下呈現(xiàn)良好的成形性。出于這個原因,本研究采用LZ91板材的筆記本頂蓋的空白,并試圖探討在室溫成形性LZ91。以確定是否斷裂將發(fā)生在有限元分析,為0.6毫米厚的LZ91板材成形極限圖還建立了如圖2(b)所示。 </p><p> 圖2 鎂合金的力學(xué)性能 (a)鎂合金的應(yīng)力應(yīng)變關(guān)系; (b)LZ91板材的(FLD)成形極限圖&l
10、t;/p><p><b> 3。有限元模型</b></p><p> 如圖3(a)所示,使用軟件DELTAMESH,由CAD軟件,PRO / E的模具幾何構(gòu)造,被轉(zhuǎn)換成有限元網(wǎng)格。被視為剛體的工具,并采用四節(jié)點殼單元建設(shè)空白網(wǎng)。從實驗中獲得的材料特性和成形極限圖中使用的有限元模擬。在初始運行中使用的其他模擬參數(shù)為:沖壓力5毫米/秒,壓邊力3千牛,庫侖摩擦系數(shù)為0.1。
11、采用有限元軟件PAM_STAMP進行分析,并在臺式電腦上進行模擬。 </p><p> 圖3 有限元模擬 (a)有限元網(wǎng)格和(b)在角落斷裂。</p><p> 首次構(gòu)建了有限元模型研究的一個鉸鏈的形成過程。由于對稱性,只有一個頂蓋的情況下的一半是模擬,如圖3(a)所示。仿真結(jié)果如圖3(b)所示,表明斷裂發(fā)生在法蘭的角落,最小厚度小于0.35毫米。這意味著斷裂問題非常嚴(yán)重,是只通過擴
12、大在法蘭圓角半徑是不能解決的。對有限元模擬進行研究的參數(shù),影響斷裂的發(fā)生以及避免斷裂,提出了幾種方法。</p><p> 4. 多工序沖壓工藝設(shè)計</p><p> 為了避免發(fā)生斷裂,多工序沖壓過程是必需的。在當(dāng)前的工業(yè)實踐中,形成頂蓋的情況下,使用鎂合金板材,通常需要至少十步的運作程序。在本研究中,嘗試了??減少運作程序。對避免斷裂,提出了幾種方法,斷裂問題的一個可行的解決方案是四個
13、操作沖壓工藝。為了限制這個文件的長度,在下面只對兩個操作和四個操作沖壓工藝進行了描述。</p><p> 4.1 兩步操作沖壓工藝</p><p> 第一是在兩個操作沖壓工藝側(cè)壁形成如圖4(a),第二是在圖4(b)提出的鉸鏈法蘭成型,鉸鏈法蘭的高度為5毫米。圖4(c)所示的厚度分布的有限元模擬得到。變形板材的最小厚度為0.41毫米及以上的成形極限圖的菌株。這意味著可避免斷裂??缺損。此
14、外,法蘭的高度符合要達到的目標(biāo)。然而,這個過程是產(chǎn)生起皺缺陷的關(guān)鍵,如圖4(d)所示,法蘭上的鉸鏈,導(dǎo)致在隨后的修剪操作中出現(xiàn)問題。因此,即使兩個操作沖壓工藝解決在角落和底部的鉸鏈法蘭斷裂問題,更好的形成過程仍有望解決鉸鏈法蘭起皺。</p><p> 圖4 兩個操作沖壓工藝 (a)形成的側(cè)壁,(b)鉸鏈,(c)厚度分布和(d)皺紋的形成</p><p> 4.2 四步操作沖壓工藝&l
15、t;/p><p> 如圖5(a)所示,四部操作在本研究中提出的形成過程三個側(cè)壁和慷慨的角半徑的鉸鏈法蘭成形開始。由于側(cè)壁接近法蘭開放和圓角半徑大于所需的法蘭成功形成無斷裂。成功地避免了這樣的過程,同時形成兩個幾何特征的難度,但增加了一張白紙的物質(zhì)流。下一步是修剪外側(cè)壁的空白,并校準(zhǔn)所需的圓角半徑4毫米到2.5毫米的值。鉸鏈,從而形成,如圖5(b)所示。第三步是開放的一面折疊,使側(cè)壁可以圍繞其周邊完成,如圖5(c)所
16、示。研究修剪額外的表外側(cè)壁在第二步第三步的效果。當(dāng)額外的工作表不修剪,在拐角處的厚度為0.381毫米,如圖5(d)所示。提高到0.473毫米厚度的角落,如圖5(e)所示。如果修剪在第二個步驟實施。在第三步的折疊過程中產(chǎn)生過多的物質(zhì),然后根據(jù)零件設(shè)計,修剪掉。最后一步是醒目的過程,是適用于校準(zhǔn)所有的圓角半徑設(shè)計值。在最終產(chǎn)品的角落的最小厚度為0.42毫米,和所有株以上的成形極限圖。這是要注意,圖5(a-c)只顯示一個鉸鏈的形成。相同的設(shè)計
17、概念,然后擴展到完整的頂蓋的沖壓工藝。</p><p><b> 5。實驗驗證</b></p><p> 為了驗證有限元分析,進行實際操作沖壓工藝與使用0.6毫米厚的LZ91表的空白。毛坯尺寸和模具的幾何形狀設(shè)計,根據(jù)有限元模擬結(jié)果。然后制造一個完善的產(chǎn)品無斷裂和皺紋,如圖6(a)所示。為了進一步驗證了有限元分析定量,厚度,在完善的產(chǎn)品的鉸鏈周圍的角落,如圖6(b
18、)所示,進行測量和對比獲得的有限元模擬,如表1所列。表1中可以看出,實驗數(shù)據(jù)和有限元計算結(jié)果是一致的。四步操作過程的有限元分析的基礎(chǔ)上設(shè)計,然后由實驗數(shù)據(jù)證實。</p><p> 圖6 完善的產(chǎn)品 (a)無斷裂和皺紋(b)測量厚度的位置。</p><p> 表1。測量的厚度比較</p><p><b> 6。結(jié)束語</b></p&
19、gt;<p> 在目前使用的實驗方法和有限元分析對鎂合金板材成形進行了研究。首先研究了AZ31和LZ的成形性。研究結(jié)果表明,LZ91板材在室溫下有良好的成形性,類似于AZ31板材成形溫度在200°C。</p><p> LZ91板材在室溫成形性能優(yōu)越,也表明在目前的筆記本頂蓋制造的成功研究。四步的操作過程使其本身在筆記本比在目前的實踐中需要較少的操作程序,形成鉸鏈的有效途徑。</
20、p><p> 同時證明了筆記本蓋,可以用LZ91, LZ91鎂合金板的沖壓工藝生產(chǎn)。在電子行業(yè)它提供了一個替代鎂合金的應(yīng)用。</p><p> Journal of Materials Processing Technology</p><p> Volume 201, Issues 1–3, 26 May 2008, Pages 247–251</p>
21、;<p> 10th International Conference on Advances in Materials and Processing Technologies — AMPT 2007</p><p> Die design for stamping a notebook case with magnesium alloy sheets</p>
22、<p> Heng-Kuang Tsai, </p><p> Chien-Chin Liao, </p><p> Fuh-Kuo Chen, </p><p> Department of Mechanical Engineering, National Taiwan University, Taipei, Taiwan, ROC</p&
23、gt;<p> Available online 8 December 2007.</p><p> http://dx.doi.org/10.1016/j.jmatprotec.2007.11.288, How to Cite or Link Using DOI</p><p> Permissions & Reprints</p><p&
24、gt;<b> Abstract</b></p><p> In the present study, the stamping process for manufacturing a notebook top cover case with LZ91 magnesium–lithium alloy sheet at room temperature was examined using
25、 both the experimental approach and the finite element analysis. A four-operation stamping process was developed to eliminate both the fracture and wrinkle defects occurred in the stamping process of the top cover case.
26、In order to validate the finite element analysis, an actual four-operation stamping process was conducted with the </p><p><b> Keywords</b></p><p> Notebook case; </p><p
27、> LZ91 magnesium–lithium alloy sheet; </p><p> Multi-operation stamping; </p><p> Formability</p><p> 1. Introduction</p><p> Due to its lightweight and good pe
28、rformance in EMI resistance, magnesium alloy has been widely used for structural components in the electronics industry, such as cellular phones and notebook cases. Although the prevailing manufacturing process of magnes
29、ium alloy products has been die casting, the stamping of magnesium alloy sheet has drawn interests from industry because of its competitive productivity and performance in the effective production of thin-walled structur
30、al components. As for stam</p><p> In the present study, the stamping process of a notebook top cover case with the use of LZ sheet was examined. The forming of the two hinges in the top cover of a notebook
31、, as shown in Fig. 1(a and b), is the most difficult operation in the stamping process due to the small distance between the flanges and the small corner radii at the flanges, as displayed in Fig. 1(c). This geometric co
32、mplexity was caused by a dramatic change in the corner radius when the flange of hinge gets too close to the </p><p> Fig. 1. Flange of hinges at notebook top cover case. (a) Hinge, (b) top cover case
33、and (c) flanges of hinge.</p><p> View thumbnail images</p><p> 2. Mechanical properties of magnesium alloy sheets</p><p> The tensile tests were performed for magnesium–lithium
34、alloy sheets of LZ61 (lithium 6%, zinc 1%), LZ91, and LZ101 at room temperature to compare their mechanical properties to those of AZ31 sheets at elevated temperatures. Fig. 2(a) shows the stress–strain relations of LZ s
35、heets at room temperature and those of AZ31 sheets at both room temperature and 200 °C. It is noted that the stress–strain curve tends to be lower as the content of lithium increases. It is also observed from F
36、ig. 2(a) that t</p><p> Fig. 2. Mechanical properties of magnesium alloy. (a) The stress–strain relations of magnesium alloy; (b) forming limit diagram (FLD) of LZ91 sheet.</p><p> View t
37、humbnail images</p><p> 3. The finite element model</p><p> The tooling geometries were constructed by a CAD software, PRO/E, and were converted into the finite element mesh, as shown in Fig.
38、3(a), using the software DELTAMESH. The tooling was treated as rigid bodies, and the four-node shell element was adopted to construct the mesh for blank. The material properties and forming limit diagrams obtained from t
39、he experiments were used in the finite element simulations. The other simulation parameters used in the initial run were: punch velocity of 5 mm/s, </p><p> Fig. 3. The finite element simulations.
40、 (a) Finite element mesh and (b) fracture at the corners.</p><p> View thumbnail images</p><p> A finite element model was first constructed to examine the one-operation forming process of the
41、 hinge. Due to symmetry, only one half of the top cover case was simulated, as shown in Fig. 3(a). The simulation result, as shown in Fig. 3(b), indicates that fracture occurs at the corners of flanges, and the minimum t
42、hickness is less than 0.35 mm. It implies that the fracture problem is very serious and may not be solved just by enlarging the corner radii at the flanges. The finite element simulati</p><p> 4. Multi
43、-operation stamping process design</p><p> In order to avoid the occurrence of fracture, a multi-operation stamping process is required. In the current industrial practice, it usually takes at least ten ope
44、rational procedures to form the top cover case using the magnesium alloy sheet. In the present study, attempts were made to reduce the number of operational procedures. Several approaches were proposed to avoid the fract
45、ure, and the four-operation stamping process had demonstrated itself as a feasible solution to the fracture problem. </p><p> 4.1. Two-operation stamping process</p><p> The first operation in
46、 the two-operation stamping process was sidewall forming as shown in Fig. 4(a), and the second one was the forming of flange of hinge presented in Fig. 4(b), the height of the flange of hinge being 5 mm. Fig. 4(c) s
47、hows the thickness distribution obtained from the finite element simulation. The minimum thickness of the deformed sheet was 0.41 mm and the strains were all above the forming limit diagram. It means the fracture de
48、fect could be avoided. In addition, the height o</p><p> Fig. 4. Two-operation stamping process. (a) Formation of sidewalls, (b) formation of hinges, (c) thickness distribution and (d) wrinkle.</p&g
49、t;<p> View thumbnail images</p><p> 4.2. Four-operation stamping process</p><p> The four-operation forming process proposed in the present study starts with the forming of three side
50、walls and the flange of the hinge with a generous corner radius, as shown in Fig. 5(a). Since the sidewall close to the flange was open and the corner radius was larger than the desired ones, the flange was successfully
51、formed without fracture. Such process successfully avoided the difficulty of forming two geometric features simultaneously, but increased the material flow of the blank sheet. Th</p><p> Fig. 5. Four-o
52、peration stamping process. (a) First operation, (b) second operation, (c) third operation, (d) without trimming and (e) with trimming.</p><p> View thumbnail images</p><p> 5. Experimental val
53、idation</p><p> In order to validate the finite element analysis, an actual four-operation stamping process was conducted with the use of 0.6 mm thick LZ91 sheet as the blank. The blank dimension and t
54、he tooling geometries were designed according to the finite element simulation results. A sound product without fracture and wrinkle was then manufactured, as shown in Fig. 6(a). To further validate the finite element an
55、alysis quantitatively, the thickness at the corners around the hinge of the sound product, as s</p><p> Fig. 6. The sound product. (a) Without fracture and wrinkle and (b) locations of thickness measur
56、ed.</p><p> View thumbnail images</p><p> Table 1. Comparison of thickness measured</p><p> Full-size table</p><p> 6. Concluding remarks</p><p> The
57、press forming of magnesium alloy sheets was studied in the present study using the experimental approach and the finite element analysis. The formability of both AZ31 and LZ sheets was examined first. The research result
58、s indicated that the LZ91 sheet has favorable formability at room temperature, which is similar to that of AZ31 sheet at the forming temperature of 200 °C.</p><p> The superior formability of LZ91
59、 sheet at room temperature was also demonstrated in the present study by successful manufacturing of the notebook top cover case. The proposed four-operation process lends itself to an efficient approach to form the hing
60、e in the notebook with fewer operational procedures than that required in the current practice.</p><p> It also confirms that the notebook cover cases can be produced with LZ91 magnesium alloy LZ91 sheet by
61、 the stamping process. It provides an alternative to the electronics industry in the application of magnesium alloys.</p><p> Acknowledgments</p><p> The authors would like to thank the Nation
62、al Science Council of the Republic of China for financially supporting this research under the Project No. NSC-95-2622-E-002-019-CC3, which made this research possible. They would also like to thank ESI, France for the h
63、elp in running the PAM_STAMP program.</p><p> References</p><p> Chen and Huang, 2003</p><p> F.K. Chen, T.B. Huang </p><p> Formability of stamping magnesium-alloy
64、 AZ31 sheets</p><p> J. Mater. Process. Technol., 142 (2003), pp. 643–647</p><p> Chen et al., 2003</p><p> F.K. Chen, T.B. Huang, C.K. Chang </p><p> Deep drawing
65、of square cups with magnesium alloy AZ31 sheets</p><p> Int. J. Mach. Tools Manuf., 43 (2003), pp. 1553–1559</p><p> Drozd et al., 2004</p><p> Z. Drozd, Z. Trojanová, S. K&
66、#250;dela </p><p> Deformation of behavior of Mg–Li–Al alloy</p><p> J. Mater. Compd., 378 (2004), pp. 192–195</p><p> Takuda et al., 1999a</p><p> H. Takuda, T. Yo
67、shii, N. Hatta </p><p> Finite-element analysis of the formability of a magnesium-based alloy AZ31 sheet</p><p> J. Mater. Process. Technol., 89/90 (1999), pp. 135–140</p><p> Ta
68、kuda et al., 1999b</p><p> H. Takuda, S. Kikuchi, T. Tsukada, K. Kubota, N. Hatta </p><p> Effect of strain rate on deformation behavior of a Mg–8.5Li–1Zn alloy sheet at room temperature</p
69、><p> Mater. Sci. Eng., 271 (1999), pp. 251–256</p><p> Corresponding author.</p><p> Copyright © 2007 Elsevier B.V. All rights reserved.</p><p> Supplementary co
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74、ing behavior of AZ31B mag...Zhongguo Youse Jinshu Xuebao/Chinese Journal..., Volume 21, Issue 9, September 2011, Pages 2023-2027Abstract</p><p> QGBF behavior for AZ31B magnesium alloy sheet with 1.0 mm
75、thick was studied. Half-sphere free gas bulging tests were performed at 300-400°C for 300 s duration to study the effects of temperature and gas pressure on QGBF properties of AZ31B sheet. The results show that the
76、bulging height increases with the gas pressure increasing at different temperatures, however, the bulging parts crack within 300 s when the forming temperature exceeds the threshold. And the bulging height exists peak va
77、lue at </p><p> View record in Scopus</p><p> Influence of cutting speed on flank temperat...Materials and Manufacturing Processes</p><p> Influence of cutting speed on flank te
78、mperat...Materials and Manufacturing Processes, Volume 26, Issue 8, August 2011, Pages 1059-1063Abstract</p><p> Chip ignition is one of the important problems in cutting magnesium alloy due to cutting t
79、emperature rise, which is mainly caused by the increase of cutting speed. In this article, we measured the mean flank temperature through mounting two K-type thermocouples in workpiece of AM50A magnesium alloy. Effect of
80、 cutting speed on the temperature rise of tool flank was analyzed. The results show that the temperature first increases and then decreases as the cutting speed increases. The chip ignition </p><p> View re
81、cord in Scopus</p><p> Influence of environmentally friendly electr...Zhongguo Youse Jinshu Xuebao/Chinese Journal...</p><p> Influence of environmentally friendly electr...Zhongguo Youse Ji
82、nshu Xuebao/Chinese Journal..., Volume 21, Issue 4, April 2011, Pages 927-931Abstract</p><p> In an alkaline basic solution containing sodium silicate, the influence of phytic acid (C6H18O24P6) concentrat
83、ion on the solution conductivity was studied. The influence regularities of environmentally friendly electrolytes, such as NaOH, Na2SiO3·9H2O, H3BO3, Na2WO4·2H2O, NaAlO2 and Na2CO3, on the solution conductivity
84、 were systematically studied by the orthogonal experiment with four factors and three levels. The results show that the solution conductivity decreases with the increase of phytic </p><p> View record in Sc
85、opus</p><p> View details of all 9 citing articles in Scopus</p><p> Provided by Scopus</p><p> Related reference work articles</p><p> e.g. encyclopedias</p>
86、<p> Sintering: ModelingEncyclopedia of Materials: Science and Techn...</p><p> 3.10 - Computational Modeling of Concrete St...Comprehensive Structural Integrity</p><p> 3.307 - Fini
87、te Element Analysis in Bone Rese...Comprehensive Biomaterials</p><p> Hard Tissues, Mechanical Properties ofEncyclopedia of Materials: Science and Techn...</p><p> NDT: Support by ModelingE
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