矩形墊片落料沖孔復(fù)合模具設(shè)計(jì)【矩形雙孔墊板】【說明書+CAD+UG】
矩形墊片落料沖孔復(fù)合模具設(shè)計(jì)【矩形雙孔墊板】【說明書+CAD+UG】,矩形雙孔墊板,說明書+CAD+UG,矩形墊片落料沖孔復(fù)合模具設(shè)計(jì)【矩形雙孔墊板】【說明書+CAD+UG】,矩形,墊片,沖孔,復(fù)合,模具設(shè)計(jì),墊板,說明書,仿單,cad,ug
畢 業(yè) 設(shè) 計(jì)
墊片落料沖孔復(fù)合模具設(shè)計(jì)
學(xué) 號(hào)
姓 名
班 級(jí)
專 業(yè)
系 部
指導(dǎo)老師
完成時(shí)間2016年11月24日至2017年 4月 20日
目 錄
引言………………………………………………………………………1
第1章沖裁件的工藝分析………………………………………………2
1.1.沖裁件的結(jié)構(gòu)工藝性………………………………………………2
1.2.沖裁件的精度………………………………………………………2
1.3.分析比較和確定工藝方案…………………………………………3
第2章對(duì)沖裁件工藝的計(jì)算及分析……………………………………4
2.1排樣的原則…………………………………………………………4
2.2排樣的搭邊…………………………………………………………4
2.3加工模具沖裁力的確定……………………………………………5
2.4卸料力、推件力和沖壓力的計(jì)算…………………………………5
2.5壓力中心的分析和減少?zèng)_裁力的方式……………………………5
第3章壓力機(jī)的選擇……………………………………………………6
3.1壓力機(jī)的選擇………………………………………………………6
3.2.壓力機(jī)的主要參數(shù)…………………………………………………6
第4章沖壓凸凹模零件的設(shè)計(jì)…………………………………………7
4.1刃口的計(jì)算及確定…………………………………………………7
4.2.凹凸模零件的具體設(shè)計(jì) …………………………………………10
4.3.模具的凹模的設(shè)計(jì)及尺寸 ………………………………………11
4.4.模具的凸模的設(shè)計(jì)及尺寸 ………………………………………11
第5章沖壓模具其他零件分析及圖紙 ………………………………12
5.1.凸凹模尺寸的計(jì)算及繪圖 ………………………………………12
5.2.其他零件的設(shè)計(jì)及繪圖…………………………………………13
結(jié)束語…………………………………………………………………19
參考文獻(xiàn)………………………………………………………………20
引言
隨著社會(huì)的進(jìn)步及發(fā)展,各種產(chǎn)品的需求日益多樣話,因此模具產(chǎn)品的挑戰(zhàn)也日益增加,同樣產(chǎn)品的性能及品質(zhì)也得到了更大的提高,因此沖壓技術(shù)也在不斷的發(fā)展及創(chuàng)新。
模具加工是工業(yè)生產(chǎn)中較為重要的部分,擁有者不可取代的地位沖壓模具更是重中之重簡單的加工方式及精確的加工結(jié)果使其在材料加工中擁有較為重要的地位。近年來沖壓成型工藝也被運(yùn)用到精密成形及電磁成型等方面。
通過資料的搜集整合及老師的指導(dǎo)從而設(shè)計(jì)出了一套符合要求的模具。沖壓模具簡稱沖模。沖壓所利用的原理是使用被安裝的模具,對(duì)想要進(jìn)行加工的零件實(shí)施力的作用讓它的外形產(chǎn)生變形或分離,從而獲得了我們想要加工的工件的一種工業(yè)相對(duì)先進(jìn)的加工方式。一般的情況下我們所使用的模具都是為零件進(jìn)行冷變形加工,著重的對(duì)材料板加工。是生產(chǎn)量很多的零件生產(chǎn)的專用工具,為了進(jìn)行批量沖壓生產(chǎn)想要的工件,就得有條件很符合我們要的沖模,沒有它加工就沒辦法法進(jìn)行;比較好的沖模,將會(huì)帶來先進(jìn)的沖壓技藝。
沖壓模具是實(shí)行沖壓少不了的設(shè)備。產(chǎn)品的品質(zhì)、生產(chǎn)的速度、生產(chǎn)所耗資源與安全問題都受到模具設(shè)計(jì)水平的帶來的大大小小的影響。沖壓模具在工作的時(shí)候,所生產(chǎn)的共件的尺寸與外形大小精度全都是模具保證,除此還有沖壓件的表面平常是不會(huì)被損毀,所用的模具的被使用年限都會(huì)很長。
沖壓磨具使用的范圍是很大的,同樣它也被用都加工形尺寸范圍較大、外形很是復(fù)雜的部件,很小的零件比如:秒表,很大的加工零件例如:汽車的部件及它的一些外面使用覆蓋件等等,當(dāng)沖壓時(shí)會(huì)使所加工的東西發(fā)生冷變形和硬化效應(yīng),常常我們得到?jīng)_壓的零件的強(qiáng)度和硬度都很好。
沖壓在一般的情況下不會(huì)有切屑碎料的出現(xiàn),不僅所需要的材料的消耗的比較少,除此之外不需要另外的加熱設(shè)備,因次是一種不僅可以省料,也有節(jié)能,所以該沖壓件的成本雖然很低但它生產(chǎn)出的東西質(zhì)量較高。
通過本次課程的設(shè)計(jì)所學(xué)的專業(yè)知識(shí)得到鞏固,也使我對(duì)沖壓模具設(shè)計(jì)得到了更深的認(rèn)識(shí)。
第1章 沖裁件的工藝分析
1.1沖裁件的結(jié)構(gòu)工藝性
如下圖1.1所示:
沖裁件的材料為Q235鋼,材料的厚度為2mm,生產(chǎn)批量為大批量生產(chǎn)。
圖1.1雙孔墊片零件圖及三維圖
此加工件所選的材料是普通碳素鋼,有著沖壓性能良好的優(yōu)點(diǎn),因此很適合沖裁。由于該沖裁件的結(jié)構(gòu)的特點(diǎn)比較簡單,并不含有尖角因此會(huì)對(duì)沖裁加工較為有利。零件中有兩個(gè)直徑為10mm的并中心對(duì)稱圓形孔,兩孔之間的距離為40mm。零件有4個(gè)半徑為2.5的圓弧角。在這些之外,由分析算得出沖裁件的孔到邊長度為8mm,符合了沖裁件最小的孔邊的長度為的要求。所以高沖裁件的結(jié)構(gòu)滿足沖裁的要求。
1.2沖裁件的精度分析
所以所有未標(biāo)注公差尺寸按照精度等級(jí)進(jìn)行查補(bǔ)
該零件的外形尺寸:
零件的內(nèi)形尺寸:
兩孔之間的距離:
根據(jù)上面的敘述就能知道,加工這個(gè)零件我們可以使用相對(duì)普通的沖裁的方法獲得。
1.3分析比較和確定工藝方案:
此零件包括落料和沖孔兩個(gè)工序,所以可以有以下三種加工方式:
加工方案一:先進(jìn)行落料,然后沖孔 采用兩套獨(dú)立的模具進(jìn)行單工序生產(chǎn)。
加工方案二:落料及沖孔同時(shí)進(jìn)行,采用復(fù)合模具進(jìn)行加工生產(chǎn)。
加工方案三:沖孔和落料逐一進(jìn)行,采用級(jí)進(jìn)模進(jìn)行生產(chǎn)。
上面三種加工的方法中第一種的模具的結(jié)構(gòu)在三種方案中是最簡單的,不過工序較多,并且有兩副模具 它的生產(chǎn)率低。生產(chǎn)出的零件精度較低。加工方案二只有一副模具,沖裁的零件的尺寸及精度相對(duì)容易保證,生產(chǎn)率較高。加工方案三盡管生產(chǎn)率較高但相對(duì)于方案二來說加工精度稍微較差。
在三種方式的的對(duì)比下欲采用方案二進(jìn)行加工生產(chǎn)。且經(jīng)過對(duì)該復(fù)合模具中的凸凹模的壁厚的檢驗(yàn)后,數(shù)據(jù)都合格,因此采用方案二進(jìn)行加工。
第2章 對(duì)沖裁件工藝的計(jì)算及分析
2.1.排樣的原則
排樣的方式
根據(jù)次沖裁件的結(jié)構(gòu)的特點(diǎn)和技術(shù)要求,為了使材料的利用率最大化,采取少廢料的排樣方式。
2.2.搭邊值的確定
通過有關(guān)的查證:被加工的工件間的搭邊的尺寸=2.2mm, 側(cè)搭邊的尺寸長度為 a=2.5mm。
1)送料步距和條料的寬度計(jì)算
送料步距S的計(jì)算:
S=D+=26+2.2=28.2mm
2)條料的寬度B的計(jì)算:
=(零件在垂直送料的方向最大值為68mm,條料是采用了剪板的方式得到,查表得:。)
3)材料的利用率
一個(gè)步距的材料利用率:
4)排樣圖 如下圖2.1所示
圖2.1排樣圖二維圖和三維圖
2.3.加工模具沖裁力的確定:
沖裁力又包括落料力以及沖孔力。
1)落料力的計(jì)算: 由計(jì)算得L=184.56mm ,查表得)
2)沖孔力的計(jì)算: (由計(jì)算得L=62.8mm,查表得)
3)沖裁力的計(jì)算:
2.4.卸料力、推件力及沖壓力的計(jì)算:
1)卸料力的計(jì)算 :
(查表可知可取0.03)
2)推件力的計(jì)算
(查資料可知h=6mm,所以n=h/t=3,所以n取3)
3)沖壓力的計(jì)算:
2.5.確定沖裁中心及降低沖裁力的方法:
1)壓力中心的選擇:
圖2.2壓力中心
如上圖2.2所示 由于該零件形狀較為對(duì)稱,所以壓力中心定為零件中心即圖中A 點(diǎn)。
2)此次采用階梯式的凸模來達(dá)到降低沖裁力的目的。
第3章 壓力機(jī)的選擇
3.1.選擇壓力機(jī):
1)根據(jù)上面計(jì)算結(jié)果,壓力機(jī)的初選型號(hào)為J23-25。
2)其主要的技術(shù)參數(shù)如下表3.1:
表3.1壓力機(jī)技術(shù)參數(shù)表
第4章 沖壓凸凹模零件的設(shè)計(jì)
4.1.刃口尺寸計(jì)算
由對(duì)該沖裁件的外形分析可知,刃口的計(jì)算可以使用分開制造進(jìn)行的方法。
1)落料件尺寸的計(jì)算公式如下:
以下尺寸由落料獲得:
可查到凸凹模的之間的距離是在0.246mm至0.36mm之間,凸模的制造公差
凹模的制造公差。經(jīng)檢驗(yàn)滿足,所以可以按上面的公式計(jì)算刃口的尺寸。
根據(jù)此加工的零件的精度要求的等級(jí)為,所以它的磨損的系數(shù)X=0.5。
2)沖孔件的尺寸的計(jì)算的公式:
,
下面的尺寸由沖孔獲得:
可查到凸凹模之間的距離是在0.246mm至0.36mm之間,凸模的制造公差
凹模的制造公差。經(jīng)檢驗(yàn)滿足,所以可以按上面的公式計(jì)算刃口的尺寸。
根據(jù)此加工的零件的精度要求的等級(jí)為,所以它的磨損的系數(shù)X=0.5。
3)中心距的計(jì)算如下:
尺寸:
4.2.沖壓凸凹模零件具體的設(shè)計(jì)
1)凹模的高度:
凹模的壁厚:
因此可以算出凹模的總長:
2)凹模寬度的計(jì)算:
所以可以確定凹模板的外形為:
3)由上面計(jì)算出的尺寸查的模架的規(guī)格尺寸:
上模座: 下模座:
導(dǎo)柱: 導(dǎo)套:
4)這套模具計(jì)劃采用彈性卸料的裝置,初步定為橡膠,它的有關(guān)的尺寸計(jì)算如下:
(1)H代表橡膠的自由高度。
所以。
(2)所將要使用的橡膠的橫截的面積的計(jì)算及確定:
A用來代表它的面積, 根據(jù)所查的資料我們知道了橡膠在預(yù)壓量為10%至15%時(shí)每的壓力是 ,因此:
(3)橡膠的平面尺寸
結(jié)合模具尺寸及所加工的零件的大小暫定為136mmx94mm,為了使橡膠的規(guī)格與模具搭配,所以橡膠的裝模高度約為24mm。
4.3凹模零件圖:
設(shè)計(jì)的凹模厚度為25mm。
圖4.1凹模二維和三維圖
1)凹模的固定方式的選擇:
凹模的固定方式大多采用螺釘及銷釘進(jìn)行固定。而所選東西的數(shù)量及大小根據(jù)凹模的大小進(jìn)行查得進(jìn)行更改。同樣它們的位置也可根據(jù)需要進(jìn)行調(diào)整。不僅是螺釘和銷釘,它們到模板邊緣的距離也要滿足相應(yīng)的要求。
凹凸模固定板:凹模固定板的厚度為12mm
圖4.2 凹模固定板二維圖和三維圖
2) 凸模固定板:
凸模固定板的厚度取24mm
圖4.3凸模固定板二維圖及三維圖
4.4.沖孔凸模尺寸的計(jì)算如下:
1)凸模長度
其中的h1是所需要的凸模的固定板的厚度,h2是所需要的空心墊板的厚度,h3所要的凹模板的厚度。
當(dāng)對(duì)凸模的強(qiáng)度進(jìn)行了校核我們知道了:這個(gè)凸模不是細(xì)長模,所以它的強(qiáng)度是足夠使用的。
2) 下面是凸模圖:
凸模的長度被計(jì)算出了為50mm
圖4.4凸模二維和三維圖
第5章 沖壓模具其他零件分析及圖紙
5.1.凸凹模尺寸的計(jì)算及繪圖:
凸凹模的長度計(jì)算如下:
其中h1是我們所需要的凹凸模的固定板的厚度,h2是我們所需要的彈性卸料板的厚度,h3 是我們所需要凸模進(jìn)入凹模的尺寸和將被使用的彈性的原件的長度等等。
圖5.1 凸凹模二維和三維圖
5.2.其他零件的設(shè)計(jì)及繪圖:
1)推薦塊的選擇:
推薦塊的尺寸如下圖所示
圖5.2推件塊二維和三維圖
2)確定卸料板的尺寸如下圖:
卸料板的厚度取12mm
圖5.3卸料板二維和三維圖
3)墊板的取值如下圖
所設(shè)計(jì)的墊板的厚度取了12mm
圖5.4墊板二維和三維圖
4)有查表可得模具上模座尺寸為:
圖5.5上模座二維和三維圖
5)下模座的尺寸規(guī)格為:
圖5.6下模座二維和三維圖
5.3模具裝配總圖:
圖5.7模具總裝圖二維及三維圖
結(jié)束語
時(shí)光匆匆而過,三年的大學(xué)生活也即將結(jié)束。短暫的畢業(yè)設(shè)計(jì)時(shí)間也在我寫完這段話時(shí)就此結(jié)束。首先我要感謝王老師對(duì)我的畢業(yè)設(shè)計(jì)的指導(dǎo),感謝各位授課老師的悉心教導(dǎo),讓我在這學(xué)會(huì)的不僅有知識(shí)收獲最大的就是明白了更多為人處世的道理。感謝各位同學(xué),你們讓我在異鄉(xiāng)感受到了不一樣的溫暖,讓我明白了怎樣更好的與他人更好的交流,在這我們互相鼓勵(lì)共勉一同成長。我非常感謝大家,馬上就要分離不必多說,各位天涯各處 唯望君安。
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[12]梅伶.模具課程設(shè)計(jì)指導(dǎo).北京:機(jī)械工業(yè)出版社.2007.
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沖壓成形與板材沖壓
1. 概述
通過模具使板材產(chǎn)生塑性變形而獲得成品零件的一次成形工藝方法叫做沖壓。由于沖壓通常在冷態(tài)下進(jìn)行,因此也稱為冷沖壓。只有當(dāng)板材厚度超過8~100mm時(shí),才采用熱沖壓。沖壓加工的原材料一般為板材或帶材,故也稱板材沖壓。某些非金屬板材(如膠木板、云母片、石棉、皮革等)亦可采用沖壓成形工藝進(jìn)行加工。
沖壓廣泛應(yīng)用于金屬制品各行業(yè)中,尤其在汽車、儀表、軍工、家用電器等工業(yè)中占有極其重要的地位。沖壓成形需研究工藝設(shè)備和模具三類基本問題。
? 板材沖壓具有下列特點(diǎn):
(1).高的材料利用率。
(2).可加工薄壁、形狀復(fù)雜的零件。
(3).沖壓件在形狀和尺寸方面的互換性好。
(4).能獲得質(zhì)量輕而強(qiáng)度高、剛性好的零件。
(5).生產(chǎn)率高,操作簡單,容易實(shí)現(xiàn)機(jī)械化和自動(dòng)化。
沖壓模具制作成本高,因此適合大批量生產(chǎn)。對(duì)于小批量、多品種生產(chǎn),常采用簡易沖模,同時(shí)引進(jìn)沖壓加工中心等新型設(shè)備,以滿足市場求新求變的需求。板材沖壓常用的金屬材料有低碳鋼、銅、鋁、鎂合金及高塑性的合金剛等。如前所述,材料形狀有板材和帶材。
沖壓生產(chǎn)設(shè)備有剪床和沖床。剪床是用來將板材剪切成具有一定寬度的條料,以供后續(xù)沖壓工序使用,沖床可用于剪切及成形。
2. 沖壓成形的特點(diǎn)
生產(chǎn)時(shí)間中所采用的沖壓成形工藝方法有很多,具有多種形式餓名稱,但塑性變形本質(zhì)是相同的。沖壓成形具有如下幾個(gè)非常突出的特點(diǎn)。
(1).垂直于板面方向的單位面積上的壓力,其數(shù)值不大便足以在板面方向上使??板材產(chǎn)生塑性變形。由于垂直于板面方向上的單位面積上壓力的素質(zhì)遠(yuǎn)小于板面方向上的內(nèi)應(yīng)力,所以大多數(shù)的沖壓變形都可以近似地當(dāng)作平面應(yīng)力狀態(tài)來處理,使其變形力學(xué)的分析和工藝參數(shù)的計(jì)算大呢感工作都得到很大的簡化。
(2).由于沖壓成形用的板材毛胚的相對(duì)厚度很小,在壓應(yīng)力作用下的抗失穩(wěn)能力也很差,所以在沒有抗失穩(wěn)裝置(如壓邊圈等)的條件下,很難在自由狀態(tài)下順利地完成沖壓成形過程。因此,以拉應(yīng)力作用為主的伸長類沖壓成形過程多于以壓應(yīng)力作用為主的壓縮類成形過程。
(3).沖壓成形時(shí),板材毛胚內(nèi)應(yīng)力的數(shù)值等于或小于材料的屈服應(yīng)力。在這一點(diǎn)上,沖壓成形與體積成形的差別很大。因此,在沖壓成形時(shí)變形區(qū)應(yīng)力狀態(tài)中的靜水壓力成分對(duì)成形極限與變形抗力的影響,已失去其在體積成形時(shí)的重要程度,有些情況下,甚至可以完全不予考慮,即使有必要考慮時(shí),其處理方法也不相同。
(4).在沖壓成形時(shí),模具對(duì)板材毛胚作用力所形成的約束作用較輕,不像體積成形(如模鍛)是靠與制件形狀完全相同的型腔對(duì)毛胚進(jìn)行全面接觸而實(shí)現(xiàn)的強(qiáng)制成形。在沖壓成形中,大多數(shù)情況下,板材毛胚都有某種程度的自由度,常常是只有一個(gè)表面與模具接觸,甚至有時(shí)存在板材兩側(cè)表面都有于模具接觸的變形部分。在這種情況下,這部分毛胚的變形是靠模具對(duì)其相鄰部分施加的外力實(shí)現(xiàn)其控制作用的。例如,球面和錐面零件成形時(shí)的懸空部分和管胚端部的卷邊成形都屬這種情況。
? ?由于沖壓成形具有上述一些在變形與力學(xué)方面的特點(diǎn),致使沖壓技術(shù)也形成了一些與體積成形不同的特點(diǎn)。由于不需要在板材毛的表面施加很大的單位壓力即可使其成形,所以在沖壓技術(shù)中關(guān)于模具強(qiáng)度與剛度的研究并不十分重要,相反卻發(fā)展了學(xué)多簡易模具技術(shù)。
由于相同原因,也促使靠氣體或液體壓力成形的工藝方法得以發(fā)展。因沖壓成形時(shí)的平面應(yīng)力狀態(tài)或更為單純的應(yīng)變狀態(tài)(與體積成形相比),當(dāng)前對(duì)沖壓成形匯中毛胚的變形與 力能參數(shù)方面的研究較為深入,有條件運(yùn)用合理的科學(xué)方法進(jìn)行沖壓加工。借助于電子計(jì)算機(jī)與先進(jìn)的測試手段,在對(duì)板材性能與沖壓變形參數(shù)進(jìn)行實(shí)時(shí)測量與分析基礎(chǔ)上,實(shí)現(xiàn)沖壓過程智能化控制的研究工作也在開展。人們在對(duì)沖壓成形過程有離開較為深入的了解后,已經(jīng)認(rèn)識(shí)到?jīng)_壓成型與原材料有十分密切的關(guān)系。所以,對(duì)板材沖壓性能即成形性與形狀穩(wěn)定性的研究,目前已成為沖壓技術(shù)的一個(gè)重要內(nèi)容。對(duì)板材沖壓性能的研究工作不僅是沖壓技術(shù)發(fā)展的需要,而且也促進(jìn)了鋼鐵工業(yè)生產(chǎn)技術(shù)的發(fā)展,為其提高板材的質(zhì)量提供了一個(gè)可靠的基礎(chǔ)與依據(jù)。
3.沖壓變形的分類
? ?沖壓變形工藝可完成多種工序,其基本工序可分為分離工序和變形工序兩大類。分離工序是使胚料的一部分與另一部分相互分離的工藝方法,主要有落料、沖孔、切邊、剖切、修整等。其中又以沖孔、落料應(yīng)用最廣。變形工序是使胚料的一部分相對(duì)于另一部分產(chǎn)生位移而不破裂的工藝方法,主要有拉深、彎曲、局部成形、脹形、翻邊、縮徑、校形、旋壓等。
從本質(zhì)上看,沖壓成形就是毛胚的變形區(qū)在外力的作用下產(chǎn)生相應(yīng)的塑性變形,所以變形區(qū)內(nèi)的應(yīng)力狀態(tài)和變形特點(diǎn)景象的沖壓成形分類,可以把成形性質(zhì)相同的成形方法概括成同一個(gè)類型并進(jìn)行體系化的研究。
絕大多數(shù)沖壓成形時(shí)毛胚變形區(qū)均處于平面應(yīng)力狀態(tài)。通常認(rèn)為在板材表面上不受外力的作用,即使有外力作用,其數(shù)值也是較小的,所以可以認(rèn)為垂直于板面方向上的應(yīng)力為零,使板材毛胚產(chǎn)生塑性變形的是作用于板面方向上相互的兩個(gè)主應(yīng)力。由于板厚較小,通常都近似地認(rèn)為這兩個(gè)主應(yīng)力在厚度方向上是均勻分布的?;谶@樣的分析,可以把各種形式?jīng)_壓成型中的毛陪變形區(qū)的受力狀態(tài)與變形特點(diǎn),在平面應(yīng)力的應(yīng)力坐標(biāo)系中與相應(yīng)的兩向應(yīng)變坐標(biāo)系中以應(yīng)力與應(yīng)變坐標(biāo)決定的位置來表示。
4.沖壓用原材料
? ?沖壓加工用原材料有很多種,它們的性能也有很大的差別,所以必須根據(jù)原材料的性能與特點(diǎn),采用不同的沖壓成形方法、工藝參數(shù)和模具結(jié)構(gòu),才能達(dá)到?jīng)_壓加工的目的。由于人們對(duì)沖壓成形過程板材毛胚的變形行為有了較為深入的認(rèn)識(shí),已經(jīng)相當(dāng)清楚的建立了由原材料的化學(xué)成分、組織等因素所決定的材料性能與沖壓成形之間的關(guān)系,這就使原材料生產(chǎn)部門不但按照沖壓件的工作條件與使用要求進(jìn)行原材料的設(shè)計(jì)工作,而且也根據(jù)沖壓件加工過程對(duì)板材性能的要求進(jìn)行新型材料的開發(fā)工作,這是沖壓技術(shù)在原材料研究方面的一個(gè)重要方向。對(duì)沖壓用原材料沖壓性能方面的研究工作有
(1)原材料沖壓性能的含義。
(2)判斷原材料沖壓性能的科學(xué)方法,確定可以確切反映材料沖壓性能的參數(shù),建立沖壓性能的參數(shù)與實(shí)際沖壓成形間的關(guān)系,以及沖壓性能參數(shù)的測試方法等。
(3)建立原材料的化學(xué)成分、組織和制造過程與沖壓性能之間的關(guān)系。沖壓用原材料主要是各種金屬與非金屬板材。金屬板材包括各種黑色技術(shù)和有色金屬板材。雖然在沖壓生產(chǎn)中所用金屬板材的種類很多,但最多的原材料蛀牙是鋼板、不銹鋼板、鋁合金板及各種復(fù)合金屬板。
5.板材沖壓性能及其鑒定方法
? ? 板材是指對(duì)沖壓加工的適應(yīng)能力。對(duì)板材沖壓性能的研究具有飛行重要的意義。為了能夠運(yùn)用最科學(xué)與最經(jīng)濟(jì)合理的沖壓工藝過程與工藝參數(shù)制造出沖壓零件,必須對(duì)作為加工對(duì)象的板材的性能具有十分清楚的了解,這樣才有可能充分地利用板材在加工方面的潛在能力。另一方面,為了能夠依據(jù)沖壓件的形狀與尺寸特點(diǎn)及其所需的成形工藝等基本因素,正確、合理地選用板材,也必須對(duì)板材的沖壓性能有一個(gè)科學(xué)的認(rèn)識(shí)與正確的判斷。評(píng)定板材沖壓性能的方法有直接試驗(yàn)法與間接試驗(yàn)法。
? ?實(shí)物沖壓試驗(yàn)是最直接的板材沖壓性能的評(píng)定方法。利用實(shí)際生產(chǎn)設(shè)備與模具,在與生產(chǎn)完全相同的條件下進(jìn)行實(shí)際沖壓零件的性能評(píng)定,當(dāng)然能夠的最可靠的結(jié)果。但是,這種評(píng)定方法不具有普遍意義,不能作為行業(yè)之間的通用標(biāo)準(zhǔn)進(jìn)行信息的交流。
? ?模擬試驗(yàn)是把生產(chǎn)中實(shí)際存在的沖壓成形方法進(jìn)行歸納與簡單化處理,消除許多過于復(fù)雜的因素,利用軸對(duì)稱的簡化了的成形方法,在保證試驗(yàn)中板材的變形性質(zhì)與應(yīng)力狀態(tài)都與實(shí)際沖壓成形相同的條件下進(jìn)行的沖壓性能的評(píng)定工作。為了保證模擬試驗(yàn)結(jié)果的可靠性與通用性,規(guī)定了私分具體的關(guān)于試驗(yàn)用工具的幾何形狀與尺寸、毛胚的尺寸、試驗(yàn)條件(沖壓速度、潤滑方法、壓邊力等)。
? ?間接試驗(yàn)法也叫做基礎(chǔ)試驗(yàn)法。間接試驗(yàn)法的特點(diǎn)是:在對(duì)板材在塑性變形過程中所表現(xiàn)出的基本性質(zhì)與規(guī)律進(jìn)行分析與研究的基礎(chǔ)上,進(jìn)一步把它和具體的沖壓成形中板材的塑性變形參數(shù)聯(lián)系起來,建立間接試驗(yàn)結(jié)果(間接試驗(yàn)值)與具體的沖壓成形性能(工藝參數(shù))之間的相關(guān)性。由于間接試驗(yàn)時(shí)所用試件的形狀與尺寸以及加載的方式等都不同于具體的沖壓成形過程,所以它的變形性質(zhì)和應(yīng)力狀態(tài)也不同于沖壓變形。因此間接試驗(yàn)所得的結(jié)果(試驗(yàn)值)并不是沖壓成形的工藝參數(shù),而是可以用來表示板材沖壓性能的基礎(chǔ)性參數(shù)。
Characteristics and Sheet Metal Forming
1. The article overview
Stamping is a kind of plastic forming process in which a part is produced by means of the plastic forming the material under the action of a die. Stamping is usually carried out under cold state, so it is also called stamping. Heat stamping is used only when the blank thickness is greater than 8~100mm. The blank material for stamping is usually in the form of sheet or strip, and therefore it is also called sheet metal forming. Some non-metal sheets (such as plywood, mica sheet, asbestos, leather)can also be formed by stamping.
?? Stamping is widely used in various fields of the metalworking industry, and it plays a crucial role in the industries for manufacturing automobiles, instruments, military parts and household electrical appliances, etc.
? ?The process, equipment and die are the three foundational problems that needed to be studied in stamping.
? ?The characteristics of the sheet metal forming are as follows:
(1)? ? High material utilization
(2)? ? Capacity to produce thin-walled parts of complex shape.
(3)? ? Good interchangeability between stamping parts due to precision in shape??
and dimension.
(4)? ? Parts with lightweight, high-strength and fine rigidity can be obtained.
(5)? ? High productivity, easy to operate and to realize mechanization and? ? automatization.
? ? The manufacture of the stamping die is costly, and therefore it only fits to mass production. For the manufacture of products in small batch and rich variety, the simple stamping die and the new equipment such as a stamping machining center, are usually adopted to meet the market demands. The materials for sheet metal stamping include mild steel, copper, aluminum, magnesium alloy and high-plasticity alloy-steel, etc.??
Stamping equipment includes plate shear punching press. The former shears plate into strips with a definite width, which would be pressed later. The later can be used both in shearing and forming.
2.Characteristics of stamping forming
There are various processes of stamping forming with different working patterns and names. But these processes are similar to each other in plastic deformation. There are following conspicuous characteristics in stamping:
(1).The force per unit area perpendicular to the blank surface is not large but is enough to cause the material plastic deformation. It is much less than the inner stresses on the plate plane directions. In most cases stamping forming can be treated approximately as that of the plane stress state to simplify vastly the theoretical analysis and the calculation of the process parameters.
(2).Due to the small relative thickness, the anti-instability capability of the blank is weak under compressive stress. As a result, the stamping process is difficult to proceed successfully without using the anti-instability device (such as blank holder). Therefore the varieties of the stamping processes dominated by tensile stress are more than dominated by compressive stress.
(3).During stamping forming, the inner stress of the blank is equal to or sometimes less than the yield stress of the material. In this point, the stamping is different from the bulk forming. During stamping forming, the influence of the hydrostatic pressure of the stress state in the deformation zone to the forming limit and the deformation resistance is not so important as to the bulk forming. In some circumstances, such influence may be neglected. Even in the case when this influence should be considered, the treating method is also different from that of bulk forming.
(4).In stamping forming, the restrain action of the die to the blank is not severs as in the case of the bulk forming (such as die forging). In bulk forming, the constraint forming is proceeded by the die with exactly the same shape of the part. Whereas in stamping, in most cases, the blank has a certain degree of freedom, only one surface of the blank contacts with the die. In some extra cases, such as the forming of the blank on the deforming zone contact with the die. The deformation in these regions are caused and controlled by the die applying an external force to its adjacent area.
Due to the characteristics of stamping deformation and mechanics mentioned above, the stamping technique is different form the bulk metal forming: The importance or the strength and rigidity of the die in stamping forming is less than that in bulk forming because the blank can be formed without applying large pressure per unit area on its surface. Instead, the techniques of the simple die and the pneumatic and hydraulic forming are developed.
Due to the plane stress or simple strain state in comparison with bulk forming, more research on deformation or force and power parameters has been done. Stamping forming can be performed by more reasonable scientific methods. Based on the real time measurement and analysis on the sheet metal properties and stamping parameters, by means of computer and some modern testing apparatus, research on the intellectualized control of stamping process is also in proceeding. It is shown that there is a close relationship between stamping forming and raw material. The research on the properties of the stamping forming, that is, forming ability and shape stability, has become a key point in stamping technology development, but also enhances the manufacturing technique of iron and steel industry, and provides a reliable foundation for increasing sheet metal quality.
3.Categories of stamping forming
? ? Many deformation processes can be done by stamping, the basic processes of the stamping can be divided into two kinds: cutting and forming.Cutting is a shearing process that one part of the blank is cut from the other. It mainly includes blanking, punching, trimming, parting and shaving, where punching and blanking are the most widely used. Forming is a process that one part of the blank has some displacement from the other. It mainly includes deep drawing, bending, local forming, bulging, flanging, necking, sizing and spinning.
In substance, stamping forming is such that the plastic deformation occurs in the deformation zone of the stamping blank caused by the external force. The stress state and deformation characteristic of the deformation zone are the basic factors to decide the properties of the stamping forming. Based on the stress state and deformation characteristics of the deformation zone, the forming methods can be divided into several categories with the same forming properties and be studied systematically.
??The deformation zone in almost all types of stamping forming is in the plane stress state. Usually there is no force or only small force applied on the blank surface. When is assumed that the stress perpendicular to the blank surface equals to zero, two principal stresses perpendicular to each other and act on the blank surface produce the plastic deformation of the material. Due to the small thickness of the blank, it is assumed approximately the two principal stresses distribute uniformly along the thickness direction. Based on this analysis, the stress state and the deformation characteristics of the deformation zone in all kinds of stamping forming can be denoted by the points in the coordinates of the plane principal stresses and the coordinates of the corresponding plane principal strains.
4.Raw materials for stamping forming
There are a lot of raw materials used in stamping forming, and the properties of these materials may have large difference. The stamping forming can be succeeded only by determining the stamping method, the forming parameters and the die structures according to the properties and characteristics of the raw materials. The deformation of the blank during stamping forming has been investigated quite thoroughly. The relationships between the material properties decided by the chemistry component and structure of the material and the stamping forming has been established clearly. Not only the proper material can be selected based on the working condition and usage demand, but also the new material can be developed according to the demands of the blank properties during processing the stamping part. This is an important domain in stamping forming research. The research on the material properties for stamping forming is as follows:
(1).Definition of the stamping property of the material.
(2).Method to judge the stamping property of the material, find parameters to express the definitely material property of the stamping forming, establish the relationship between the property parameters and the practical stamping forming, and investigate the testing methods of the property parameters.
(3).Establish the relationship among the chemical component, structure, manufacturing process and stamping property.
?? The raw materials for stamping forming mainly include various metals and nonmetal plate. Sheet metal includes both ferrous and nonferrous metals. Although a lot of sheet metals are used in stamping forming, the most widely used materials are steel, stainless steel, aluminum alloy and various composite metal plates.
5.Stamping forming property of sheet metal and its assessing method
The stamping forming property of the sheet metal is the adaptation capability of the sheet metal to stamping forming. It has crucial meaning to the investigation of the stamping forming property of the sheet metal. In order to produce stamping forming parts with most scientific, economic and rational stamping forming process and forming parameters, it is necessary to understand clearly the properties of the sheet metal, so as to utilize the potential of the sheet metal fully in the production. On the other hand, to select plate material accurately and rationally in accordance with the characteristics of the shape and dimension of the stamping forming part and its forming technique is also necessary so that a scientific understanding and accurate judgment to the stamping forming properties of the sheet metal may be achieved.
There are direct and indirect testing methods to assess the stamping property of the sheet metal?.Practicality stamping test is the most direct method to assess stamping forming property of the sheet metal. This test is done exactly in the same condition as actual production by using the practical equipment and dies. Surely, this test result is most reliable. But this kind of assessing method is not comprehensively applicable, and cannot be shared as a commonly used standard between factories.
? ? The simulation test is a kind of assessing method that after simplifying and summing up actual stamping forming methods, as well as eliminating many trivial factors, the stamping properties of the sheet metal are assessed, based on simplified axial-symmetric forming method under the same deformation and stress states between the testing plate and the actual forming states. In order to guarantee the reliability and generality of simulation results, a lot of factors are regulated in detail, such as the shape and dimension of tools for test, blank dimension and testing conditions(stamping velocity, lubrication method and blank holding force, etc).???Indirect testing method is also called basic testing method its characteristic is to connect analysis and research on fundamental property and principle of the sheet metal during plastic deformation, and with the plastic deformation parameters of the sheet metal in actual stamping forming, and then to establish the relationship between the indirect testing results(indirect testing value) and the actual stamping forming property (forming parameters). Because the shape and dimension of the specimen and the loading pattern of the indirect testing are different from the actual stamping forming, the deformation characteristics and stress states of the indirect test are different from those of the actual one. So, the results obtained form the indirect test are not the stamping forming parameters, but are the fundamental parameters that can be used to represent the stamping forming property of the sheet metal.
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