購(gòu)買設(shè)計(jì)請(qǐng)充值后下載,,資源目錄下的文件所見即所得,都可以點(diǎn)開預(yù)覽,,資料完整,充值下載可得到資源目錄里的所有文件。。?!咀ⅰ浚篸wg后綴為CAD圖紙,doc,docx為WORD文檔,原稿無(wú)水印,可編輯。。。具體請(qǐng)見文件預(yù)覽,有不明白之處,可咨詢QQ:12401814
第7章
沖壓及薄板液壓成形的案例分析:
7.1。案例1:精密反射板的液壓成形
7.1.1。問(wèn)題陳述
為了空間通信,直徑為12m被稱為平方公里陣列(SKA)的反射鏡/天線陣列被確定了三種方法制造?12米的反射鏡,即:
(a) 鋁合金板組裝和一個(gè)鋼筋支撐的結(jié)構(gòu)
(b) 復(fù)合材料制造形成的反光板
(c) 模具(超高頻- D)內(nèi)高壓成形的板材
在這些方法中,超高頻- D被認(rèn)為是最經(jīng)濟(jì)的,并能產(chǎn)生所需的表面光潔度和精度,并且對(duì)高壓成形的小尺寸(?50寸)和大到(?12米)反射[Antsos2003]的有限元進(jìn)行了模擬與檢查。這一分析表明部分液壓成行后的回彈性較大。這導(dǎo)致維護(hù)最后反射剖面(圖0.2毫米的均方根(RMS)的耐受性是相當(dāng)困難的。(7.1)。這是關(guān)于確定最佳的模具或模具的幾何形狀,以減少所需內(nèi)高壓成形?12米的反射回彈得一項(xiàng)調(diào)查。
7.1.2。序列形成
目前生產(chǎn)的直徑30英寸較小的反射鏡如圖7.2
第1步:板材由于重力下垂
第2步:板料的頂部和底部之間模具的夾緊
第3步:脹形高端板材模具型腔
7.1.3。目標(biāo)和方法途徑
這項(xiàng)研究的具體目標(biāo)是:
(a) 預(yù)測(cè)在反射?12米高壓成形回彈
(b) 確定影響反射器回彈的工具和材料參數(shù)
(c) 通過(guò)反射的回彈補(bǔ)償估算模具/模具的幾何形狀
下面概述的是任務(wù)
任務(wù)1:確定使用雙軸片凸起材料AA3003 – O的性能測(cè)試
任務(wù)2:調(diào)查片材各向異性,一個(gè)?。?50英寸)內(nèi)高壓成形反射對(duì)回彈和變
薄的影響。
任務(wù)3:調(diào)查表模摩擦條件下的界面效應(yīng)在模具板下垂由于重力作用,以及變薄
和內(nèi)高壓成形反射模具回彈?12米的結(jié)構(gòu)。
任務(wù)4:估計(jì)?12米反射鏡最佳模具結(jié)構(gòu),讓沿曲線長(zhǎng)度可以很容易地補(bǔ)償回
彈均勻分布
任務(wù)5:量化對(duì)細(xì)化和優(yōu)化模具結(jié)構(gòu)板材厚度的影響
7.1.4。有限元(FE)仿真
使用單元進(jìn)行了利用商業(yè)有限元代碼PAMSTAMP2000對(duì)液壓成形過(guò)程模擬圖7.3顯示了在PAMSTAMP有限元模型等軸測(cè)視圖2000板殼單元。有限元模擬輸入條件列于表鋁AA3003- O獲得粘性壓力的測(cè)試。當(dāng)剛性空白是仿照彈塑性凸凹模的模板的有限元模擬。由于軸對(duì)稱變形和邊界條件只有四分之一的空白部分為模板根據(jù)庫(kù)侖摩擦定律的接口摩擦系數(shù)(μ)= 0.1的假設(shè)。對(duì)工作表上模夾緊進(jìn)行了模擬移動(dòng),流體(或空氣)壓力是通過(guò)使用有限元軟件PAMSTAMP的'Aquadraw'。
7.1.5.內(nèi)高壓成形材料
各向異性反射板對(duì)回彈和變薄分配一個(gè)小尺寸(?50寸)有限元進(jìn)行了兩個(gè)為形成?50英寸直徑的反射板的各向異性模擬。初始毛坯直徑= 57.5英寸(?一千四百六十毫米)。系數(shù)的各向異性三個(gè)方向(0 °,45°和90°)分別輸入到有限元模擬,以評(píng)估在形成反射的各向異性對(duì)厚度分布和回彈的影響,這些各向異性值選擇上,真正形成條件是可以仿效的。然而,他們不反映??鋁合金3003- O的(圖7.4)的實(shí)際值準(zhǔn)確的各向異性值鋁合金3003- O的需要從拉伸試驗(yàn)確定。希爾的標(biāo)準(zhǔn)是1948年的產(chǎn)量用來(lái)代表在有限元模擬板材各向異性
圖7.4:沿軋制方向(0°),對(duì)角方向(45°)和橫向方向(90°)用有限元模擬塑性的變比
板材各向異性的影響中形成的細(xì)化反射分布:
即使形成了各向異性材料特性被用來(lái)描述了有限元模擬片材(圖7.5)。間伐比例并沒(méi)有明顯改變沿圓周的一部分,對(duì)材料性能各向同性和各向異性的有限元模擬說(shuō)明有限元模擬預(yù)計(jì)在高壓成形的一部分最大減薄了14%最大減薄觀測(cè)到是該地區(qū)靠近頂端的圓頂,但不是在圓頂?shù)捻旤c(diǎn)。由于壓應(yīng)力沿對(duì)社會(huì)形成的板材何處接觸到這些地點(diǎn)的模具表面徑向表行事不變,細(xì)化超過(guò)150毫米的中心曲線長(zhǎng)度。
材料各向異性的回彈
——觀察更多的回彈有限元各向同性和各向異性模型相比,(圖7.6)
——對(duì)于各向異性的情況下,不同的回彈沿圓周的一部分。這種變化是由于回彈在沿軋制屈服應(yīng)力和橫向的滾動(dòng)方向的各向異性常數(shù)屈服準(zhǔn)則中引入了變異
圖7.5:有限元模擬預(yù)測(cè)各向異性材料的稀疏分布插圖:圖為?50寸長(zhǎng))的
反射曲線變形示意圖
圖7.6:各向異性板材有限元模擬形成?50英寸的反射回彈
7.1.6:?12米反射工藝參數(shù)和刀具幾何參數(shù)對(duì)回彈的影響
高壓成形?12米的反射鏡有限元模擬進(jìn)行了使用代碼PAMSTAMP2G到研究了工藝參數(shù),即以下效果:
(a) 由于模具其自身重量導(dǎo)致下垂
(b)片材和模具界面摩擦條件
(c)模具的幾何形狀(法蘭角)
液壓成形零件的回彈:
圖7.7:為假定模具有限元模擬示意圖
表7.2:刀具幾何形狀在模擬中使用
?12米天線模具結(jié)構(gòu)設(shè)計(jì)在圖7.7和表7.2顯示了以目前的模具成型制造中使用更小的反射器為基礎(chǔ)內(nèi)高壓成形有限元天線進(jìn)行的模擬三個(gè)階段。在第一階段,該表將死腔由于其本身重量的重力下垂進(jìn)行模擬(重力模擬)。在第二階段,由被認(rèn)為是(夾緊模具板控股模擬)。第三階段,進(jìn)行回彈模擬后其次進(jìn)行內(nèi)高壓成形過(guò)程有限元模擬,表7.3顯示了有限元模擬矩陣,研究在?12米反射回彈(a)界面條件及(b)模具的幾何形狀的影響。三種不同的接口之間的表和法蘭在模具的幾何形狀不同的角度摩擦條件和模具幾何形狀考慮對(duì)摩擦條件影響。
表7.3:有限元模擬矩陣來(lái)確定影響界面摩擦及模具幾何尺寸對(duì)回彈(法蘭角),并在?12m變薄形成反射
研究法蘭回彈影響的角度:
在與該模具的法蘭角的增加形成了部分回彈。在?12米反射器,Z軸方向的最小為10毫米,觀察回彈位移為30度角,而在Z法蘭?16毫米的法蘭60度角位移觀測(cè)方向?yàn)樽畲蠡貜棥?
回彈法蘭角在30 °形成的部分是非線性分布。這是很難修改模具,以補(bǔ)償非線性回彈。因此,這是傾向于選擇與模具結(jié)構(gòu)法蘭角45度回彈的變化曲線長(zhǎng)度,并且可以很容易地補(bǔ)償上模具幾何形狀。
隨著75 °法蘭角,徑向回彈比其他法蘭角較?。?0°,45°和60°)。因此,在模具上的選擇75 °法蘭角,被認(rèn)為是形成和薄鋼板厚度0.25英寸?12米的最佳反射
圖7.8:比較Z位移在換用不同的角度法蘭液壓成形零件回彈的模具結(jié)構(gòu)(初始板材厚度=0.25英寸)
圖7.9:在換用不同的角度法蘭液壓成形模具結(jié)構(gòu)部分(初始板厚=0.25英寸)
比較回彈的徑向位移。
在最后的反射回彈中工具之間摩擦片的影響:
圖7.10顯示了與法蘭不同的摩擦角為60度的條件反射形成的細(xì)化比較,細(xì)化在不改變摩擦條件的顯著變化。
在液壓成形,片自由凸起(統(tǒng)一拉伸)到上模腔,并逐漸從外圍向中心接觸到上模,表是夾在邊緣以避免在高壓成形過(guò)程中的任何物質(zhì)運(yùn)動(dòng)進(jìn)入體腔。
因?yàn)?,不存在?fù)債表和上模之間的相對(duì)運(yùn)動(dòng)。因此,效果對(duì)形成中的一部分變薄摩擦是微不足道的。
圖7.10:預(yù)測(cè)不同回彈的?12米法蘭角60°(初始板材厚度=0.25英寸)反射界面摩擦條件比較。
7.1.7。摘要和結(jié)論
在這項(xiàng)研究中,有限元(FE)板材液壓成形與模具(超高頻- D)的?50英寸和?12米的反射進(jìn)行了使用商業(yè)有限元程序PAMSTAMP2G/PAMSTAMP2000年的模擬過(guò)程:
(a) 對(duì)制造的超高頻三維?12米反射鏡的可行性論證
(b) 預(yù)測(cè)在高壓成形過(guò)程?12米后反射鏡的回彈
(c) 確定的工藝參數(shù)影響/材料特性(即各向異性片材,板材初始厚度,界面摩擦條件下,重力和模具的幾何尺寸對(duì)回彈)形成的反射器
(d) (d) 計(jì)算在回彈形成的反射可以很容易地通過(guò)修改模具的補(bǔ)償?shù)囊粋€(gè)幾何尺寸。
這項(xiàng)研究得出的結(jié)論是:
形成反射超高頻- D的可行性過(guò)程:通過(guò)有限元模擬,用模具(超高頻- D)的內(nèi)高壓成形過(guò)程中形成大的反光板使用的可行性證明。有一個(gè)表面精度要求0.2毫米的RMS上的內(nèi)形成反射朗讀,在超高頻- D過(guò)程是有厚度的變化而變形, 還有的由于殘留在反射形成的反射回彈應(yīng)力,因此,為了獲得所需的關(guān)于最終形成準(zhǔn)確地表反射剖面,對(duì)模具/模具幾何體必須進(jìn)行修改。因此需要在設(shè)計(jì)上與Z軸方向高硬度模具結(jié)構(gòu),盡量慎重考慮減少上層偏轉(zhuǎn)死于高勢(shì)力。觀察附近的頂點(diǎn)?12米天它是很好的資產(chǎn)負(fù)債表內(nèi)的材料最高為14%,變薄,線 斷裂極限為AA3003 – O。
影響工具之間的摩擦片:工藝條件,即下垂的空白由于重力作用,模具的幾何形狀(法蘭角)和初始板厚影響了部分形成的細(xì)化。然而,在部分變薄分布發(fā)生的變化僅± 2%,有限元模擬關(guān)于在液壓成形零件變薄界面摩擦條件的影響被認(rèn)為是微不足道的。
各向異性對(duì)板料回彈的影響:由于AA 3003 – O為非各向異性數(shù)據(jù),假設(shè)的數(shù)據(jù)被用來(lái)量化回彈各向異性的影響,在板材各向異性導(dǎo)致圓周的一部分非均勻回彈。因此,需要考慮材料的各向異性估計(jì)和補(bǔ)償在模具的幾何形狀的回彈,回彈是受a)板材各向異性,B)初始板厚,C)下垂的空白,由于重力和d)模具的幾何形狀的相互影響。
模法蘭角對(duì)回彈的影響:入模腔片材下垂導(dǎo)致更多的物質(zhì)流入模腔,從而減少了減薄形成的部分,增加成型后的回彈。因此,模具的幾何形狀(法蘭角)顯著影響了內(nèi)高壓成形零件的回彈。高等法蘭角允許在空白以及在初始階段的夾緊下垂更多的物質(zhì)流進(jìn)模腔,因此,較大的模具幾何法蘭角導(dǎo)致更多的回彈。
然而,更大的法蘭角導(dǎo)致回彈更加均勻分布,這是可取的。統(tǒng)一回彈可以更容易地通過(guò)修改模具幾何尺寸進(jìn)行補(bǔ)償。其中模具幾何尺寸(法蘭角)在本研究中考慮,75°法蘭角的發(fā)現(xiàn)使得了初步板材厚度6.35毫米(0.25英寸)的材料回彈分布均勻。
板材厚度對(duì)回彈的影響:對(duì)于較大的法蘭角,入模腔更多的物質(zhì)流。此外,小薄床單的抗彎曲和更容易流動(dòng)到模具型腔。太多的材料進(jìn)入模腔流導(dǎo)致皺紋和折疊。
- 模具結(jié)構(gòu)的“最佳“回彈補(bǔ)償:較低的值幾何模法蘭角(30°,45°和60 °)導(dǎo)致了非均勻回彈這是很難彌補(bǔ)。高等法蘭角導(dǎo)致過(guò)度進(jìn)入模具型腔物質(zhì)流的重力及控股階段,從而導(dǎo)致皺紋和折疊。因此,“最優(yōu)“模具結(jié)構(gòu)(法蘭角)取決于初始片厚度,負(fù)債表和厚度的減小。據(jù)估計(jì),在形成?12米反射鏡厚度為4.75毫米(0.185英寸)的初始表的“最佳“死幾何(法蘭角)將在60°?75 °。
顯示對(duì)應(yīng)的拉丁字符的拼音
(編號(hào)):
長(zhǎng)春理工大學(xué)光電信息學(xué)院
畢 業(yè) 設(shè) 計(jì)(論 文)譯文
姓 名
王懷鋒
學(xué) 院
機(jī)電工程分院
專 業(yè)
機(jī)械設(shè)計(jì)制造及其自動(dòng)化
學(xué) 號(hào)
0951317
指導(dǎo)教師
仲叢華
2013
年
4
月
11
日
冷沖模具使用壽命的影響及對(duì)策
沖壓模具概述
沖壓模具--在冷沖壓加工中,將材料(金屬或非金屬)加工成零件(或半成品)的一種特殊工藝裝備,稱為冷沖壓模具(俗稱冷沖模)。沖壓--是在室溫下,利用安裝在壓力機(jī)上的模具對(duì)材料施加壓力,使其產(chǎn)生分離或塑性變形,從而獲得所需零件的一種壓力加工方法。
沖壓模具的形式很多,一般可按以下幾個(gè)主要特征分類:
1.根據(jù)工藝性質(zhì)分類
(1)沖裁模 沿封閉或敞開的輪廓線使材料產(chǎn)生分離的模具。如落料模、沖孔模、切斷模、切口模、切邊模、剖切模等。
(2)彎曲模 使板料毛坯或其他坯料沿著直線(彎曲線)產(chǎn)生彎曲變形,從而獲得一定角度和形狀的工件的模具。
(3)拉深模 是把板料毛坯制成開口空心件,或使空心件進(jìn)一步改變形狀和尺寸的模具。
(4)成形模 是將毛坯或半成品工件按圖凸、凹模的形狀直接復(fù)制成形,而材料本身僅產(chǎn)生局部塑性變形的模具。如脹形模、縮口模、擴(kuò)口模、起伏成形模、翻邊模、整形模等。
2.根據(jù)工序組合程度分類
(1)單工序模 在壓力機(jī)的一次行程中,只完成一道沖壓工序的模具。
(2)復(fù)合模 只有一個(gè)工位,在壓力機(jī)的一次行程中,在同一工位上同時(shí)完成兩道或兩道以上沖壓工序的模具。
(3)級(jí)進(jìn)模(也稱連續(xù)模) 在毛坯的送進(jìn)方向上,具有兩個(gè)或更多的工位,在壓力機(jī)的一次行程中,在不同的工位上逐次完成兩道或兩道以上沖壓工序的模具。
沖冷沖模全稱為冷沖壓模具
冷沖壓模具是一種應(yīng)用于模具行業(yè)冷沖壓模具及其配件所需高性能結(jié)構(gòu)陶瓷材料的制備方法,高性能陶瓷模具及其配件材料由氧化鋯、氧化釔粉中加鋁、鐠元素構(gòu)成,制備工藝是將氧化鋯溶液、氧化釔溶液、氧化鐠溶液、氧化鋁溶液按一定比例混合配成母液,滴入碳酸氫銨,采用共沉淀方法合成模具及其配件陶瓷材料所需的原材料,反應(yīng)生成的沉淀經(jīng)濾水、干燥,煅燒得到高性能陶瓷模具及其配件材料超微粉,再經(jīng)過(guò)成型、燒結(jié)、精加工,便得到高性能陶瓷模具及其配件材料。本發(fā)明的優(yōu)點(diǎn)是本發(fā)明制成的冷沖壓模具及其配件使用壽命長(zhǎng),在沖壓過(guò)程中未出現(xiàn)模具及其配件與沖壓件產(chǎn)生粘結(jié)現(xiàn)象,沖壓件表面光滑、無(wú)毛刺,完全可以替代傳統(tǒng)高速鋼、鎢鋼材料。
冷沖模具主要零件
冷沖模具是沖壓加工的主要工藝裝備,沖壓制件就是靠上、下模具的相對(duì)運(yùn)動(dòng)來(lái)完成的。加工時(shí)由于上、下模具之間不斷地分合,如果操作工人的手指不斷進(jìn)入或停留在模具閉合區(qū),便會(huì)對(duì)其人身安全帶來(lái)嚴(yán)重威脅。
(一)模具的主要零件、作用及安全要求
1.工作零件凸凹模是直接使坯料成形的工作零件,因此,它是模具上的關(guān)鍵零件。凸凹模不但精密而且復(fù)雜,它應(yīng)滿足如下要求:
(1)應(yīng)有足夠的強(qiáng)度,不能在沖壓過(guò)程中斷裂或破壞.
(2)對(duì)其材料及熱處理應(yīng)有適當(dāng)要求,防止硬度太高而脆裂。
2.定位零件定位零件是確定坯件安裝位置的零件,有定位銷(板)、擋料銷(板)、導(dǎo)正銷、導(dǎo)料板、定距側(cè)刀、側(cè)壓器等。設(shè)計(jì)定位零件時(shí)應(yīng)考慮操作方便,不應(yīng)有過(guò)定位,位置要便于觀察,最好采用前推定位、外廓定位和導(dǎo)正銷定位等。
3.壓料、卸料及出料零件壓料零件有壓邊圈、壓料板等。
壓邊圈可對(duì)拉延坯料加壓邊力,從而防止坯料在切向壓力的作用下拱起而形成皺褶。壓料板的作用是防止坯料移動(dòng)和彈跳。頂出器、卸料板的作用是便于出件和清理廢料。它們由彈簧、橡膠和設(shè)備上的氣墊推桿支撐,可上下運(yùn)動(dòng),頂出件設(shè)計(jì)時(shí)應(yīng)具有足夠的頂出力,運(yùn)動(dòng)要有限位。卸料板應(yīng)盡量縮小閉合區(qū)域或在操作位置上銑出空手槽。暴露的卸料板的四周應(yīng)設(shè)有防護(hù)板,防止手指伸入或異物進(jìn)入,外露表面棱角應(yīng)倒鈍。
4.導(dǎo)向零件導(dǎo)柱和導(dǎo)套是應(yīng)用最廣泛的一種導(dǎo)向零件。其作用是保證凸凹模在沖壓工作時(shí)有精確的配合間隙。因此,導(dǎo)柱、導(dǎo)套的間隙應(yīng)小于沖裁間隙。導(dǎo)柱設(shè)在下模座,要保證在沖程下死點(diǎn)時(shí),導(dǎo)柱的上端面在上模板頂面以上最少5至10毫米。導(dǎo)柱應(yīng)安排在遠(yuǎn)離模塊和壓料板的部位,使操作者的手臂不用越過(guò)導(dǎo)柱送取料。
5.支承及夾持零件它包括上下模板、模柄、凸凹模固定板、墊板、限位器等。
上下模板是冷沖模具的基礎(chǔ)零件,其他各種零件都分別安裝固定在上面。模板的平面尺寸,尤其是前后方向應(yīng)與制件相適應(yīng),過(guò)大或過(guò)小均不利于操作。
有些模具(落料、沖孔類模具)為了出件方便,需在模架下設(shè)墊板。這時(shí)墊板最好與模板之間用螺釘連接在一起,兩墊板的厚度應(yīng)絕對(duì)相等。墊板的間距以能出件為準(zhǔn),不要太大,以免模板斷裂。
6.緊固零件它包括螺釘、螺母、彈簧、柱銷、墊圈等,一般都采用標(biāo)準(zhǔn)件。冷沖模具的標(biāo)準(zhǔn)件用量較多,設(shè)計(jì)選用時(shí)應(yīng)保證緊固和彈性頂出的需要,避免緊固件暴露在表面操作位置上,防止碰傷人手和妨礙操作。
冷沖模具的發(fā)展
改革開放以來(lái),隨著國(guó)民經(jīng)濟(jì)的高速發(fā)展,市場(chǎng)對(duì)冷沖模具的需求量不斷增長(zhǎng)。近年來(lái),冷沖模具工業(yè)一直以15%左右的增長(zhǎng)速度快速發(fā)展,冷沖模具工業(yè)企業(yè)的所有制成分也發(fā)生了巨大變化,除了國(guó)有專業(yè)模具廠外,集體、合資、獨(dú)資和私營(yíng)也得到了快速發(fā)展。
隨著與國(guó)際接軌的腳步不斷加快,市場(chǎng)競(jìng)爭(zhēng)的日益加劇,人們已經(jīng)越來(lái)越認(rèn)識(shí)到產(chǎn)品質(zhì)量、成本和新產(chǎn)品的開發(fā)能力的重要性。而冷沖模具制造是整個(gè)鏈條中最基礎(chǔ)的要素之一,冷沖模具制造技術(shù)現(xiàn)已成為衡量一個(gè)國(guó)家制造業(yè)水平高低的重要標(biāo)志,并在很大程度上決定企業(yè)的生存空間。
近年許多冷沖模具企業(yè)加大了用于技術(shù)進(jìn)步的投資力度,將技術(shù)進(jìn)步視為企業(yè)發(fā)展的重要?jiǎng)恿?。一些?guó)內(nèi)模具企業(yè)已普及了二維CAD,并陸續(xù)開始使用UG、Pro/Engineer、I-DEAS、Euclid-IS等國(guó)際通用軟件,個(gè)別廠家還引進(jìn)了Moldflow、C-Flow、DYNAFORM、Optris和MAGMASOFT等CAE軟件,并成功應(yīng)用于沖壓模的設(shè)計(jì)中。
以汽車覆蓋件模具為代表的大型沖壓模具的制造技術(shù)已取得很大進(jìn)步,東風(fēng)汽車公司模具廠、一汽模具中心等模具廠家已能生產(chǎn)部分轎車覆蓋件模具。此外,許多研究機(jī)構(gòu)和大專院校開展模具技術(shù)的研究和開發(fā)。經(jīng)過(guò)多年的努力,在模具CAD/CAE/CAM技術(shù)方面取得了顯著進(jìn)步;在提高模具質(zhì)量和縮短模具設(shè)計(jì)制造周期等方面做出了貢獻(xiàn)。
雖然中國(guó)冷沖模具工業(yè)在過(guò)去十多年中取得了令人矚目的發(fā)展,但許多方面與工業(yè)發(fā)達(dá)國(guó)家相比仍有較大的差距。例如,精密加工設(shè)備在冷沖模具加工設(shè)備中的比重比較低;CAD/CAE/CAM技術(shù)的普及率不高;許多先進(jìn)的模具技術(shù)應(yīng)用不夠廣泛等等,致使相當(dāng)一部分大型、精密、復(fù)雜和長(zhǎng)壽命冷沖模具依賴進(jìn)口。
隨著科學(xué)技術(shù)的不斷進(jìn)步,現(xiàn)代工業(yè)產(chǎn)品的生產(chǎn)日益復(fù)雜與多樣化,產(chǎn)品性能和質(zhì)量也在不斷提高,因而對(duì)冷沖壓技術(shù)提出了更高的要求.為了使冷沖壓技術(shù)能適應(yīng)各工業(yè)部門的需要,冷沖壓技術(shù)自身也在不斷革新和發(fā)展.冷沖壓技術(shù)的發(fā)展思路就是盡可能地完善和擴(kuò)充冷沖壓工藝的優(yōu)點(diǎn),克服其缺點(diǎn).在冷沖壓技術(shù)的發(fā)展過(guò)程中,應(yīng)注意以下幾方面:
(1)冷沖壓技術(shù)的發(fā)展過(guò)程中應(yīng)正確地確定工藝參數(shù)及冷沖模具工作部分的形狀與尺寸,提高沖壓件的質(zhì)量、縮短新產(chǎn)品試制周期,應(yīng)在加強(qiáng)沖壓成形理論研究的基礎(chǔ)上,使沖壓成形理論達(dá)到能對(duì)生產(chǎn)實(shí)際起指導(dǎo)作用,逐步建立起一套密切結(jié)合生產(chǎn)實(shí)際的先進(jìn)的工藝分析計(jì)算方法.國(guó)外已開始采用彈塑性有限元法對(duì)汽車覆蓋零件的成形過(guò)程進(jìn)行應(yīng)力應(yīng)變分析和計(jì)算機(jī)模擬,以預(yù)測(cè)某一工藝方案對(duì)零件成形的可能性和可能出現(xiàn)的問(wèn)題。
(2)加快產(chǎn)品更新?lián)Q代,克服模具設(shè)計(jì)周期長(zhǎng)的缺點(diǎn).應(yīng)大力開展模具計(jì)算機(jī)輔助設(shè)計(jì)和制造(CAD/CAM)技術(shù)的研究.在我國(guó),目前要特別注意加強(qiáng)多工位級(jí)進(jìn)模CAD/CAM技術(shù)的研究。
(3)滿足大量生產(chǎn)需要以及減輕勞動(dòng)強(qiáng)度.應(yīng)加強(qiáng)冷沖壓生產(chǎn)的機(jī)械化和自動(dòng)化研究,使一般中、小件能在高速壓力機(jī)上采用多工位級(jí)進(jìn)模生產(chǎn),達(dá)到生產(chǎn)高度自動(dòng)化,進(jìn)一步提高沖壓的生產(chǎn)率。
(4)擴(kuò)大冷沖壓生產(chǎn)的運(yùn)用范圍.使冷沖壓既適合大量生產(chǎn),也適合小批量生產(chǎn);既能生產(chǎn)一般精度的產(chǎn)品,也能生產(chǎn)精密零件.應(yīng)注意開發(fā)如精密沖裁(特別是厚料精沖)、高能成形、軟模成形、施壓和超塑性加工等新成形工藝,還要推廣簡(jiǎn)易模(軟模和低熔點(diǎn)合金模)、通用組合模、數(shù)控沖床等設(shè)備的運(yùn)用。
此外,對(duì)沖壓板料性能的改進(jìn),模具新材料、模具新加工方法的開發(fā)也應(yīng)進(jìn)一步加強(qiáng)。
冷沖模具使用壽命的影響及對(duì)策
冷沖模具的使用壽命是以沖制出的工件數(shù)量來(lái)計(jì)算的。影響冷沖模壽命的因素很多。主要有模具結(jié)構(gòu)設(shè)計(jì)、制造模具所用凸模和凹模的材料、模具的熱處理質(zhì)量與表面強(qiáng)化、沖模零件的制造精度和冷沖壓材料的選取。除此之外,還有沖模的安裝、調(diào)整、使用以及維修等。
1.模具設(shè)計(jì)對(duì)壽命的影響
(1)排樣設(shè)計(jì)的影響排樣方法與搭邊值對(duì)模具壽命的影響很大,過(guò)小的搭邊值,往往是造成模具急劇磨損和凸、凹??袀闹匾?。從節(jié)約材料出發(fā),搭邊值愈小愈好,但搭邊值小于一定數(shù)值后,對(duì)模具壽命和剪切表面質(zhì)量不利。在沖裁中有可能被拉人模具問(wèn)隙中,使零件產(chǎn)生毛刺,甚至損壞模具刃口,降低模具壽命。因此,在考慮提高材料利用率的同時(shí),必須根據(jù)零件產(chǎn)量、質(zhì)量和壽命,確定排樣方法和搭邊值。
(2)凹模結(jié)構(gòu)的影響對(duì)容易產(chǎn)生應(yīng)力集中而開裂的凹模結(jié)構(gòu),可以采用組合結(jié)構(gòu)或鑲拼結(jié)構(gòu),以及預(yù)應(yīng)力結(jié)構(gòu),從而提高模具使用壽命。
(3)間隙的影響當(dāng)間隙過(guò)小時(shí),壓縮擠壓利害,摩擦力增大,磨損增大,側(cè)面的磨損加劇,沖裁后卸料和推件時(shí),材料與凸、凹模之間的摩擦還將造成刃口側(cè)面的磨損比端面的磨大大,同時(shí)也容易造成凸、凹模溫度很高,把金屬碎屑吸附在刃口側(cè)面,形成金屬瘤,使凸、凹模出現(xiàn)崩刃或脹裂現(xiàn)象。因此,過(guò)小的間隙對(duì)模具壽命極為不利。間隙太大,會(huì)增加凸模與凹模端面邊緣的集中應(yīng)力,致使壓應(yīng)力急劇增加,于是刃口邊很快屈服變形而失去棱角。因此又增加了沖裁力,進(jìn)而使刃口邊更快磨損,降低模具壽命。但為了減小凸、凹模的磨損,延長(zhǎng)模具使用壽命,在保證沖裁件質(zhì)量的前提下,設(shè)計(jì)時(shí)適當(dāng)采用較大間隙是十分必要的。
(4)模具導(dǎo)向結(jié)構(gòu)對(duì)壽命的影響可靠的導(dǎo)向?qū)τ跍p小工作零件的磨損,避免凸、凹模啃傷是非常有效的。特別對(duì)無(wú)問(wèn)隙或小問(wèn)隙沖裁模、復(fù)合模和多工位級(jí)進(jìn)模更為重要。為提高模具壽命,必須根據(jù)工序和零件精度要求,正確選擇導(dǎo)向形式和導(dǎo)向精度,所選擇導(dǎo)向精度應(yīng)高于凸、凹模的配合精度。
(5)冷沖壓材料選取的影響冷沖壓材料應(yīng)滿足制件的設(shè)計(jì)要求和沖壓工藝要求,否則容易損傷模具,降低模具使用壽命。冷沖壓材料表面質(zhì)量不好,沖壓時(shí)制件易破裂,也易擦傷模具。冷沖壓材料塑性不好,變形量小,沖壓時(shí)制件易破裂,也易擦傷模具。另外,材料的厚度公差應(yīng)符合國(guó)家標(biāo)準(zhǔn)。因?yàn)橐桓睕_模適用于一定材料的厚度,成形、彎曲、翻邊、引伸模具的凸、凹模結(jié)構(gòu)間隙是直接根據(jù)材料厚度來(lái)確定的。所以材料厚度不均勻,會(huì)導(dǎo)致廢品產(chǎn)生和模具損壞。
2.模具材料對(duì)模具壽命的影響
模具材料對(duì)模具壽命的影響是模具材料性質(zhì)、化學(xué)成分、組織結(jié)構(gòu)、硬度和冶金質(zhì)量等的綜合反映。其中,材料性質(zhì)和熱處理質(zhì)量影響最為明顯。模具材料性質(zhì)對(duì)模具壽命的影響是很大的。如將同一種工件,使用不同的模具材料做彎曲試驗(yàn),試驗(yàn)結(jié)果:用9Mn2V材料,其壽命為5萬(wàn)次;用Crl2MoV滲氮,其壽命可達(dá)40萬(wàn)次。因此,在選用材料時(shí),應(yīng)根據(jù)制件的批量大小,合理選用模具材料。模具工作零件的硬度對(duì)模具壽命的影響也很大。但并不是硬度愈高、模具壽命愈長(zhǎng)。這是因?yàn)橛捕扰c強(qiáng)度、韌性及耐磨性等有密切的關(guān)系。有的沖模要求硬度高,壽命長(zhǎng)。如采用T10鋼制造沖模,硬度為54~58HRC,只沖幾千次,制件毛刺就很大。如果將硬度提高到60~64HRC,則刃磨壽命可達(dá)2~3萬(wàn)次。但如果繼續(xù)提高硬度,則會(huì)出現(xiàn)早期斷裂。有的沖模硬度不宜過(guò)高,如采用Crl2MoV制造凹模硬度為58~62HRC時(shí),一般壽命為2—3萬(wàn)件,失效形式是崩刃和開裂以及如果將硬度降到54~58HRC,壽命提高到5~6萬(wàn)件,但硬度降低到50~53HRC會(huì)出現(xiàn)凹模刃口易磨鈍現(xiàn)象。由此可見,模具硬度必須根據(jù)材料性質(zhì)和失效形式而定。應(yīng)使硬度、強(qiáng)度、韌性及耐磨性、耐疲勞強(qiáng)度等達(dá)到特定沖壓工序所需要的最佳配合。
3.模具的熱處理質(zhì)量與表面強(qiáng)化對(duì)壽命的影響
模具的熱處理質(zhì)量對(duì)模具的性質(zhì)與使用壽命影響很大。實(shí)踐證明,模具工作零件的淬火變形與開裂,使用過(guò)程中早期斷裂,雖然與材料的冶金質(zhì)量、鍛造質(zhì)量、模具結(jié)構(gòu)及加工有關(guān),但與模具的熱處理關(guān)系更大。根據(jù)模具失效原因的分析統(tǒng)計(jì),熱處理不當(dāng)引起的失效占50% 以上。實(shí)踐證明,高級(jí)的模具材料必須配以正確的熱處理工藝,才能真正發(fā)揮材料的潛力。模具工作零件表面強(qiáng)化處理的目的,是獲得外硬內(nèi)韌的效果,從而得到硬度、耐磨性、韌性、耐疲勞強(qiáng)度的良好配合。模具表面強(qiáng)化處理方法很多,表面處理的新技術(shù)工藝發(fā)展很快。除氮碳共滲和離子氮化、滲硼、滲鈮、滲釩、表面鍍硬鉻和電火花強(qiáng)化外,化學(xué)氣相沉積(CVD)和物理氣相沉積(PVD)已逐步采用。經(jīng)CVD和PVD處理后,模具表面覆蓋一層超硬物質(zhì),如TiC、TiN等。硬度極高、耐磨性、耐蝕性、抗黏合性很好,可提高模具壽命幾倍到幾十倍。
4.沖模零件的制造精度對(duì)模具壽命的影響
沖模制造的精度與使用壽命關(guān)系很大,特別是模具表面粗糙度對(duì)模具影響很大。如用Crl2MoV鋼制造落料模,如果表面粗糙度值R =1.6 m時(shí),其壽命為3萬(wàn)件左右。如經(jīng)精拋光,表面粗糙度值R =0.4 m,壽命可提高到4—5萬(wàn)件。因此,對(duì)模具工作零件表面,一般都要經(jīng)過(guò)磨削、研磨、拋光等精加工和精細(xì)加工。
5.其他方面對(duì)模具壽命的影響
(1)壓力機(jī)的精度不高,也易使沖模損壞。
(2)沖模在壓力機(jī)上安裝的正確與否及操作者的技術(shù)水平高低,對(duì)模具壽命也有很大影響。
(3)沖模的保管和維護(hù)好壞,以及使用潤(rùn)滑劑的情況,也影響模具使用壽命。
結(jié)語(yǔ)
在實(shí)際生產(chǎn)中,對(duì)于薄板沖模使用,很少出現(xiàn)非正常磨損的情況。但對(duì)于厚板沖模時(shí)則發(fā)現(xiàn)易出現(xiàn)非正常磨損,我們總是針對(duì)出現(xiàn)的問(wèn)題進(jìn)行研究總結(jié)。因?yàn)橐桓崩錄_模,從設(shè)計(jì)、加工制造、裝配、調(diào)試到安裝、使用,都耗費(fèi)了眾多工時(shí),同時(shí)沖模的凸、凹模使用的材料,大都是優(yōu)質(zhì)合金鋼。因此,沖模的成本都是比較高的。所以在生產(chǎn)中了解影響沖模壽命的因素及采取相應(yīng)的對(duì)策來(lái)指導(dǎo)生產(chǎn),具有重大的現(xiàn)實(shí)意義。
Die Life of cold stamping die and improvements
Overview of stamping die
Stamping Die - Stamping in the cold, the material (metal or non-metallic) processing into parts (or half) of a special technical equipment, called cold stamping die (commonly known as Die). Press - is at room temperature, using the die installed in the press to put pressure on the material to produce a separation or plastic deformation, and thus to obtain the necessary parts of a pressure processing method.
Stamping die in the form of many, the general categories according to the following main features:
1. According to the technical nature of
(1) Die along the closed or open contour the material are derived from mold. If blanking die, punch die, cut off the mold, cut mode, cutting mode, split mode, etc..
(2) bending mode to blank or blank sheet along a straight line (curved line) to bend, deform, and thus obtain a certain angle and shape of the workpiece in the mold.
(3) The drawing die is made of the blank sheet opening hollow, or hollow pieces of further changes to the shape and size of the mold.
(4) Die rough or semi-finished workpiece is convex according to plan, direct copy the shape of the die shape, the material itself, generate only local plastic deformation of the mold. Such as the bulging mode, reducing the die, expansion die, forming die rolling, flanging mold, plastic mold.
2. According to the degree classification process combination
(1) single process model in a press tour, just completed a die stamping process.
(2) composite model is only one station, in a press tour, at the same station at the same time to complete more than two or two die stamping process.
(3) Progressive Die (also known as the modulus of continuity) in the feeding direction, rough, with two or more of the station, at the press of a visit, work in different places on the completion of two or two successive Road over stamping die process.
Chong called cold stamping die Die-wide.
Cold stamping die is used in cold stamping die mold industry, and accessories required for high-performance structural ceramic materials, preparation methods, high-performance ceramic materials, molds and accessories from the zirconium oxide and yttrium aluminum powder increases, Pr element composition, Preparation is the solution of zirconia, yttria solution, praseodymium oxide solution, according to a certain percentage of alumina solution when mixed liquor, ammonium bicarbonate infusion, by co-precipitation synthesis of ceramic materials, molds and accessories needed for raw materials, reaction precipitate generated by the treatment, drying, calcining and accessories by high performance ceramic mold material superfine powder, and then after forming, sintering, finishing, they will have high-performance ceramic materials, molds and accessories. Advantages of this invention is the invention made of cold stamping dies and parts and long service life, the process does not appear in the press and its parts and stamping die bond generated the phenomenon of stamping surface is smooth, no glitches, can replace traditional high-speed steel, tungsten steel.
Die with the main parts
Die stamping tools is the main process equipment, stamping rely on the relative movement under the mold completed. Processing time because the upper and lower mold between the constant division and, if continued operation of the fingers of workers to enter or remain in the mold closed, there will certainly pose a serious threat to their personal safety.
(A) of the mold main parts, function and safety requirements
1. Working parts is a direct punch to blank forming the working parts, therefore, it is the key to mold parts. Punch not only sophisticated and complex, it should meet the following requirements:
(1) be of sufficient strength, can not be broken or destroyed during stamping.
(2) should be appropriate to its material and heat treatment requirements, to prevent too high hardness and brittle fracture.
2. Positioning parts positioning part is to determine the location of the parts installed blank, there are pins (board), gauge pin (plate), lead is sold, guide plate, knife set from the side, side pressure etc.. Design should be considered when positioning parts easy to operate and should not have had orientation, location to facilitate observation, preferably in the forward position, contouring to correct the pin location and positioning.
3. Binder, unloading and discharging parts binder components are blank holder, binder board.
Blank holder pressure can drawing blank holder force, thereby preventing billets under the action of the tangential pressure arch formed folds. The role of pressure plate to prevent movement and bounce blank. Top of the device, discharge board's role is to facilitate the pieces and clean up waste. Them by the spring, rubber and equipment, putting on the air-cushion support, can move up and down, knocking out pieces of the design should have enough top output, movement to the limited spaces. Stripper plate area should be minimized or closed position in the operating groove milling out empty-handed. Exposure of the stripper plate should have protection around the plate, to prevent finger inserted into or foreign objects inside, exposed surface edges should be blunt down.
4. Guide parts and guide sleeve guide pin is the most widely used part of a guide. Its role is to ensure punch the punching clearance when accurate match. Therefore, the guide posts, guide cover the gap should be less than the blanking clearance. Guide Post located next mold base, to ensure that the stroke bottom dead center, the lead column in the template on the face over the top for at least 5 to 10 mm. Guide columns should be arranged far away from the module and the pressure plate in the area, so the operator's arms do not get to take over the lead column material.
5. Supporting and clamping the upper and lower parts which includes templates, die handle, fixed plate punch, plate, stopper, etc..
Up and down the template is the basis of the cold die parts, other parts are respectively fixed at the top. Template plane size, especially around the direction to be compatible with the workpiece, too large or too small are not conducive to action.
Some molds (blanking, punching type mold) to the pieces of convenience, be set up under the mold plate. At this time the best and the template plate connected between the screw, the two plate thickness should be absolutely equal. Plate spacing out the pieces to be able to prevail, not too much, so as not to break the template.
6. Fastening parts which includes screws, nuts, springs, pins, washers, etc., are generally used standard parts. Die more with the amount of standard parts, design choice and flexibility should be tightened to ensure the top out of the need to avoid exposure to the surface fastener operating position, the staff and impede operation to prevent bumps.
Die with the development
Since reform and opening, with the rapid development of the national economy, the market demand with the growing Die. In recent years, Die with the industry has been around 15% growth rate of the rapid development of industrial enterprises with ownership Die components also changed dramatically, in addition to the professional mold factory outside of state-owned, collective, joint ventures, wholly-owned and private has been a rapid development.
As with the accelerating pace of international integration, the increasing competition in the market, it has been increasingly recognized product quality, cost, and new product development capacities. The cold die manufacturing is the most basic elements of the chain, one of the cold die manufacturing technology to measure a country's manufacturing sector has become an important symbol of the level, and largely determine the viability of enterprises.
Die with enterprises to increase in recent years many technological advances for investment, technological progress will be seen as an important driving force for enterprise development. Some domestic enterprises have popularized the two-dimensional mold CAD, and gradually began to use UG, Pro / Engineer, I-DEAS, Euclid-IS and other international common software, individual manufacturers have also introduced Moldflow, C-Flow, DYNAFORM, Optris and MAGMASOFT etc. CAE software, and successfully applied in stamping die design.
A car cover mold as the representative of a large stamping die manufacturing technology has made great progress, Dongfeng Motor Corporation mold factory, mold manufacturers such as FAW mold center has been able to produce some car cover mold. In addition, many research institutions and universities to carry out technology research and development of mold. After years of effort, in the mold CAD / CAE / CAM technology has made remarkable progress; in improving quality and reducing mold die design and manufacturing cycle, and so contributed.
Although China Die with the industry over the past decade has made remarkable development, but in many ways compared with the industrialized countries there is still a large gap. For example, the precision machining equipment, processing equipment in Die with the relatively low proportion; CAD / CAE / CAM technology penetration is not high; many advanced mold technology not widely so, resulting in a considerable number of large, sophisticated, complex and long Die life with dependence on imports.
????With the continuous progress of science and technology, modern industrial production of increasingly complex and diverse, product performance and quality is ever increasing, thus the cold stamping technology put forward higher requirements. In order to adapt to the cold stamping technology industry needs, cold stamping technology itself also in innovation and development. cold stamping technology idea is to improve and expand as much as possible the advantages of the cold stamping process, to overcome its shortcomings. in the cold stamping technology development, should note the following aspects:
(1) cold stamping technology process parameters should be properly identified and Die with the work of some of the shape and size, to improve the quality of stamping parts and shorten the new product production cycle should be in strengthening the metal forming the basis of theoretical studies, to metal forming theory to practice can produce a direction, and gradually establish a close connection with the actual production of the advanced process of calculation. abroad have begun to use plastic finite element method, automobile parts forming process of the stress and strain analysis and computer simulation to predict the forming part of a process plan on the possibilities and potential problems.
(2) to accelerate product replacement, mold design to overcome the shortcomings of a long cycle. Should vigorously carry out computer-aided design and manufacture of molds (CAD / CAM) Research. In my country, paying particular attention to strengthening the multi-position progressive die CAD / CAM Technology.
(3) to meet the needs of mass production, and reduce labor intensity. Should strengthen cold stamping of mechanized and automated, so that the average, small pieces of high-speed presses in a multi-position progressive die production, production reached a high degree of automation to further improve stamping productivity.
(4) expand the scope of application of cold stamping production. So cold pressing both suitable for mass production, but also for small batch production; both the general accuracy of product production, but also can produce precision parts. Should pay attention to development such as fine blanking (especially thick material fine blanking), forming high-energy, soft mold forming, pressure and processing new superplastic forming process, but also promote the easy mode (soft mode and the low melting point alloy mold), Universal Hybrid model, the use of CNC punch press and other equipment.
In addition, the performance improvement of sheet metal stamping, mold new material, die development of new processing methods should be further strengthened.
Die with life and Countermeasures
Die with the life of the workpiece by punching out the number of terms. Many factors affect the life Die. There are die structure design, manufacture molds used in the punch and die materials, die quality and surface hardening heat treatment, precision die manufacturing parts and cold stamping materials selection. In addition, there are die installation, adjustment, use and maintenance.
1. Die Design on Life
(1) Layout design of layout methods and take the boundary value a great impact on the die life, too small to take the boundary value, often causing rapid wear and convex mold, die bite wounds on the. Starting from material savings, take the boundary value smaller the better, but take the edge is less than some value, the cut surface of the mold and the quality of life adversely. There will be left behind in the blanking die Q-gap were to produce spare parts glitch, or even damage the die edge, reduce die life. Therefore, consider increasing the material utilization of the same time, parts must yield, quality and life expectancy to determine the layout methods and take the boundary.
(2) die structure prone to stress concentration on the cracking of the die structure, composite structure can be used or mosaic structure, and prestressed structure to enhance the mold life.
(3) the impact of clearance when the gap is too small, compressed extrusion of interest, increased friction, increased wear, the wear side of aggravated discharge and push pieces after blanking time, materials and convex, the friction between die will cause wear and tear than the end edge on the side of the grinding much, but also easily lead to convex, concave mold temperature is high, the adsorption of metal de