四墊圈沖孔、落料復(fù)合模設(shè)計【多墊圈】【說明書+CAD】
四墊圈沖孔、落料復(fù)合模設(shè)計【多墊圈】【說明書+CAD】,多墊圈,說明書+CAD,四墊圈沖孔、落料復(fù)合模設(shè)計【多墊圈】【說明書+CAD】,墊圈,沖孔,復(fù)合,設(shè)計,說明書,仿單,cad
目錄
一、設(shè)計多墊圈復(fù)合模的出發(fā)點………………………………………… 2
二、多墊圈復(fù)合模沖壓的工藝分析……………………………………… 4
1、材料…………………………………………………………………4
2、尺寸精度……………………………………………………………4
3、沖壓工藝分析………………………………………………………4
三、沖壓工藝方案的制定………………………………………………… 6
1、單墊圈、多墊圈復(fù)合模的比較……………………………………6
2、主要難題及解決方法………………………………………………6
四、沖壓工藝的計算……………………………………………………… 8
(一)、排樣計算……………………………………………………………8
(二)、計算各工序壓力、選擇壓力機……………………………………10
(三)、復(fù)合模的凸、凹模的計算…………………………………………11
1、凸、凹模的刃口計算………………………………………………11
2、凸凹模的設(shè)計………………………………………………………13
(四)、彈簧的選用和計算…………………………………………………14
五、選擇壓力機型號……………………………………………………… 16
六、主要零部件結(jié)構(gòu)與尺寸的選擇和確定……………………………… 17
七、繪制模具總裝圖……………………………………………………… 21
八、繪制主要非標準零部件圖…………………………………………… 23
九、結(jié)束語………………………………………………………………… 24
參考文獻…………………………………………………………………… 25
一、設(shè)計多墊圈復(fù)合模的出發(fā)點
因冷沖壓能得到形狀較復(fù)雜的制件,且加工精度高,尺寸穩(wěn)定,互換性好,在大量生產(chǎn)條件下,制件成本低,生產(chǎn)效率高,易于自動化。所以隨著我國工業(yè)的現(xiàn)代化,冷沖壓工藝正越來越多地被采用,并在使用中得到不斷發(fā)展。
在沖壓生產(chǎn)中,沖裁所使用的模具稱為沖裁模。它是沖壓生產(chǎn)中不可缺少的工藝設(shè)備,良好的模具結(jié)構(gòu)是實現(xiàn)工藝方案的可靠保證。
常用的沖裁模典型結(jié)構(gòu)主要有單工序沖裁模、復(fù)合模、連續(xù)模。由這次畢業(yè)設(shè)計的題目《多墊圈復(fù)合?!房芍枰O(shè)計一付加工墊圈的模具。墊圈常用于各種儀器儀表,更可起到防震、絕緣的作用,且年產(chǎn)量高。
考慮到單工序沖裁生產(chǎn)效率低、難以滿足該零件的年產(chǎn)量要求,故考慮采用復(fù)合沖裁與連續(xù)沖裁。
復(fù)合沖裁是沖床在一次行程中,板料在沖模內(nèi)經(jīng)過一次定位,能夠同時完成兩種或兩種以上不同工序的沖壓過程。對于該零件采用復(fù)合模能保證沖壓件的形位精度和尺寸精度,且生產(chǎn)效率也高。
連續(xù)沖裁是在一套沖模里,把同一個沖壓件的幾個工序排列成一定順序。加工時,沖床每次行程,條料在沖模里依次移動一個位置。在不同的位置(簡稱工位)上,分別進行工件所要求的不同工步(即連續(xù)沖壓工序中每一單獨的工序),除最初幾次沖程外,以后每次沖程都可以完成一個沖壓件。對于該零件采用連續(xù)沖裁雖能滿足其生產(chǎn)效率,但零件的材料為橡膠,質(zhì)軟,采用連續(xù)沖裁難以保證沖壓件的形位精度和尺寸精度,而且其模具制造、安裝較復(fù)合模要復(fù)雜。
通過對單工序模、復(fù)合模、連續(xù)模的比較分析,決定采用復(fù)合模形式比較合適。
而這次畢業(yè)設(shè)計的任務(wù)是設(shè)計出一付能一次沖出多個墊圈的復(fù)合模,其主要是因為某廠生產(chǎn)的墊圈用處廣泛,規(guī)格繁多,每年的墊圈單件產(chǎn)量多在百萬以上。由于廠家競爭激烈,產(chǎn)品面臨著殘酷的考驗。為此,必須在內(nèi)部通過優(yōu)化加工工藝,提高材料利用率、生產(chǎn)效率等來降低成本。
首先,在指導(dǎo)老師的建議下,將各種墊圈的規(guī)格大小進行了分類比較。然后設(shè)想能否在單沖墊圈的基礎(chǔ)上,一模同時沖壓出多個各種規(guī)格的產(chǎn)品。以達到既能提高工作效率,又能提高材料的利用率。
在查閱了大量的文獻資料后,初步掌握了模具的設(shè)計方法,由于時間倉促,水平有限,整個設(shè)計必然有許多不足之處,這有待于今后在工作、學(xué)習(xí)中的不斷更正和改進。
二、多墊圈復(fù)合模沖壓的工藝分析
1、 材料:
該零件的材料為人造橡膠,厚度為2mm,年產(chǎn)量百萬以上。常用于各種儀表、儀器等。
2、 尺寸精度:
因為材料性質(zhì),所取的凸凹模的間隙應(yīng)偏小,故模具零件的加工精度較高。所以可以初定最大外圓尺寸Φ500-0.1mm、及最小內(nèi)孔尺寸Φ120+0.070均為IT10級。
3、 沖壓工藝性分析:
在排列出的各種規(guī)格墊圈中,在最不影響產(chǎn)品質(zhì)量情況下及在符合產(chǎn)品所允許的公差范圍里,選出厚度一樣(均為2mm)、材料相同的墊圈,將其內(nèi)外結(jié)構(gòu)、尺寸進行整理如圖所示:
原墊圈的尺寸 調(diào)整后的墊圈尺寸
從圖中可以看出,尺寸經(jīng)過調(diào)整后,墊圈的內(nèi)外圈關(guān)系正好是相互套裁的。 墊圈甲(外徑為Φ50)的孔徑為墊圈乙(外徑Φ36)的外徑,墊圈乙的孔徑為墊圈丙(外徑Φ26)的外徑,墊圈丙的孔徑為墊圈?。ㄍ鈴溅?6)的外徑。這正符合一模同時沖壓下四個墊圈的條件。從其普遍的墊圈性質(zhì)和客戶的要求來說,略作尺寸改動并不影響產(chǎn)品的使用,也不影響產(chǎn)品的質(zhì)量。所以如果將原來的一次沖一模改進為一次沖出四模,不僅可使材料的利用率成倍的提高,生產(chǎn)效率更能大幅度地提高四倍。并節(jié)省了人工、電耗等。經(jīng)濟效益十分可觀。
三、 沖壓工藝方案的制定
1、 方案的制定:
沖壓墊圈工序較簡單,基本工序是沖孔、落料。
比較項目
單墊圈復(fù)合模
多墊圈復(fù)合模
材料的利用率
K=31%
K=61%
每一次沖得產(chǎn)品
1件
4件
產(chǎn)品質(zhì)量
佳
佳
調(diào)整單件批量
容易
不易
模具開制成本估價
2000元/付×4=8000元
8000元/付
模具壽命
長
長
模具維護
簡單
較難
沖壓操作
簡單
簡單
該廠原來都是以單墊圈形式開制的復(fù)合模,現(xiàn)在多以用多墊圈復(fù)合模。為了更清晰了解這兩種復(fù)合模沖壓成型產(chǎn)品的優(yōu)劣性,下面列表將它們進行比較:
從上述列表中可以看出,多墊圈復(fù)合模在關(guān)鍵兩項——材料利用率和生產(chǎn)效率的對比上遙遙領(lǐng)先于單墊圈復(fù)合模。從某種意義上來講,該模具滿足了單件產(chǎn)品需求量巨大的情況。同時使本廠的競爭力大大提高。
所以,采用多墊圈復(fù)合模沖制零件。
2、 主要難題及解決方法。
(1) 主要難題:由于該零件的結(jié)構(gòu)簡單,整個沖制過程并不存在什么問題。但是該復(fù)合模由多付凸凹模組合而成,所以如何將凸凹模中的產(chǎn)品一次卸出來成為一個主要難題。
(2) 解決方法:如下圖所示是凸凹模與卸料板的關(guān)系。
圖1 圖2
由圖1、2中可看出,凸凹模是尾部相互固定組合而成。而卸料板也必須與其同步而行,一起動作,才能成功卸料。
所以,需要在組合凸凹模上以穿孔機穿孔,然后經(jīng)由線切割割出腰圓長槽,用銷子8將卸料圈串合起來。就能成功使卸料板、凸凹模成為一體在腰圓槽里上下同時動作,以達到一次將沖壓的四片墊圈卸出來的目的。
四、 沖壓工藝的計算
模具設(shè)計,牽涉面廣,要了解模具的加工工藝,不然設(shè)計出的模具無法加工就失敗了。首先要確定凸凹模的間隙,沖裁模凸模的橫斷面一般都小于凹???。凸凹模之間應(yīng)有適當(dāng)?shù)目障?,但間隙的大小牽涉范圍很多。間隙過小時,會使沖裁后的落料件尺寸增大,沖孔件尺寸縮小;間隙過大時,會使沖裁結(jié)束后的落料件尺寸縮小,沖孔件尺寸增大。
間隙大小還對模具壽命有影響。當(dāng)間隙增大時,模具壽命有明顯增長。
同時,間隙的大小還和工件平直、沖裁面毛刺大小等密切相關(guān)。
故應(yīng)考慮墊片的產(chǎn)品性質(zhì),主要要求為:產(chǎn)品要平直、無毛刺。產(chǎn)品材料為人造橡膠,適宜選偏小間隙,查表后可確定其雙邊間隙為0.08mm。
其次,要計算凸、凹模的尺寸大小、沖裁件的排樣方式和了解被加工零件的沖裁力、卸料力、推料力等,還要根據(jù)計算出來的沖壓力選擇壓力機。了解該壓力機的開閉合高度,安裝板的大小等,才能考慮模具的總厚度是多少并確定模架。根據(jù)沖壓零件的材料、批量來定模具凸凹模的材料,淬火硬度等。
(一)、排樣計算
為了合理利用材料,并盡可能的節(jié)省材料,應(yīng)對沖裁件進行合理地排樣。
1、板料規(guī)格的確定:零件材料為人造橡膠,厚度為2mm,選用2mm×500mm×500mm。
2、方案的確定:
方案一:采用單排法
1)查表得搭邊值 a=2mm,a1=1.5mm 則
B=D+2a=50+2×2=54mm
2)確定步距s
s=D+a1=50+1.5=51.5mm
3)裁板條數(shù)n1=Bb/B=500/54=9條,余14mm;
每條沖零件個數(shù)n2=(Lb-a1)/s=(500-1.5)/51.5=9個,余35mm;
每板沖零件總個數(shù)n總=n1×n2=9×9=81個
板料的利用率為
η總=[n總×π(R2-r2)/LbBb]×100%
=[81×3.14×(252-62)/500×500]×100%
=60%
方案二:采用多排。
1)如圖所示,根據(jù)相關(guān)幾何知識可知
B=D+2a
=[(50+1.5)sin60+50]+2×2
=44.6+50+4
=98.6mm
2)步距s=D+a1=50+1.5=51.5mm
3)裁板條數(shù)n1=Bb/B =500/98.6=5條,余7mm;
每條沖零件個數(shù)n2=(Lb-a1)/s
=(500-1.5)/51.5
=9個
余35mm;
每板沖零件總個數(shù)n總=2n1×n2=90個
板料利用率為
η總=[n總×π(R2-r2)/LbBb]×100%
=[90×3.14×(252-62)/500×500]×100%
=66.6%
由上述可知,采用單排的板料利用率為60%,采用多排的板料利用率可提高到66%。很明顯,多排方式是能達到提高材料利用率的要求,所以采用多排方式。
(二)、計算各工序壓力、選擇壓力機
該產(chǎn)品只需沖孔、落料復(fù)合沖壓一道工序,并根據(jù)復(fù)合模的結(jié)構(gòu)能一次沖出四個墊圈。
已知產(chǎn)品材料為人造橡膠,厚度為2mm,查表得τ=50N/mm2
四墊圈沖裁力P沖=KLtτ
=1.3×(50+36+26+16+12)×3.14×2×50
=57148N
人造橡膠的K卸系數(shù)根據(jù)材料性質(zhì)并查表得K卸=0.01
四墊圈卸料力P卸=K卸P沖
=0.01×57148
=571.48N
同理得,K頂=0.015
四墊圈頂料力P頂=K頂P沖
=0.015×57148
=857.22N
多墊圈復(fù)合模結(jié)構(gòu)主要是采用彈性卸料裝置和上出料方式的沖裁工藝力,故
P總=P沖+P卸+P頂
=57148+571.48+857.22
=58576.7N
=58.5767.×103N
=59KN
按現(xiàn)有規(guī)格選用100KN壓力機比較適宜。但是考慮到模具結(jié)構(gòu),為了能滿足模具最大封閉閉合高度,選用160KN壓力機才更適宜。
(三)、復(fù)合模的凸、凹模刃口計算
1、復(fù)合模的凸、凹模刃口計算
1)沖孔部分:
凸凹模中的凹模部分和沖孔凸模部分,可采用分開加工。
如圖所示,該零件的材料為人造橡膠,厚度t=2mm。屬于一般的沖孔、落料件。Φ120+0.070mm由沖孔獲得。查雙邊間隙表得,Zmin=0.0615mm,Zmax=0.09mm則Zmax-Zmin=0.09-0.0615=0.0285mm
零件精度IT10以上,χ=1。按照模具制造精度高于沖裁件精度3~4級的原則,設(shè)凸、凹模按IT5級制造,沖孔Φ120+0.070mm,查表得,δ凸=δ凹=0.008mm。
d凸=(d+χΔ)0-δ凸=(12mm+1×0.070)0-0.008=12.070-0.008mm
d凹=(d+χΔ+Zmin)0+δ凹=(12mm+1×0.070+0.0615)0+0.008
=12.13150+0.008mm
校核:δ凸+δ凹≤Zmax-Zmin
δ凸+δ凹=0.008+0.008=0.016mm<0.0285mm
故凸、凹模刃口尺寸可確定。
根據(jù)模具結(jié)構(gòu)要求,可確定凸模以臺肩固定的方式固定。
因是采用彈性卸料板的小凸模,可確定凸模長度為:
L=h1+h2+δ+h
式中L—凸模長度
h1—凸模固定板厚度(20mm)
h2—卸料板厚度(15mm)
δ—材料厚度(2mm)
h—附加長度,它包括凸模的修模量,凸模進入凹模的深度,凸模固定板與卸料板之間的安全距離。一般取h=15~20mm。
故總長度L=20+15+2+15=52mm 即確定的凸模長度為52mm。
詳細凸模尺寸見零件圖第9頁。
2)落料部分:
圓形落料凹模和凸凹模中的凸模部分,亦采用分開加工。
Φ500-0.1mm由落料獲得。查表得,δ凹=0.011mm,δ凸=0.011mm。
D凹=(D-χΔ)0+δ凹=(50-1×0.1)0+0.011=49.90+0.011mm
D凸=(D-χΔ-Zmin)0-δ凸=(50-1×0.1-0.0615) 0-0.011
=49.83850-0.011mm
校核:δ凸+δ凹=0.011+0.011=0.022mm≤0.0285mm
所以凸、凹模尺寸可確定。
該復(fù)合模的凹模刃口為直筒形,用螺釘固定在上模座上,因此它屬于倒裝復(fù)合模。
根據(jù)模具結(jié)構(gòu)要求,確定凹模壁厚為35mm。其實際尺寸可參看零件圖第4頁。
另外,因為該模具的四付凸凹模之間尺寸有互借關(guān)系,所以按其名義尺寸進行制造。
2、凸、凹模的設(shè)計
該模具為同時沖出四個墊圈的復(fù)合模。這四個墊圈的尺寸是相互套裁的。用復(fù)合模沖出四個墊圈(這四個墊圈尺寸按由大到小分別以甲、乙、丙、丁命名),理應(yīng)在同一位置上要布置八套凸、凹模。由于其中有三個是套裁的,需要五付凸、凹模。這副模具進一步展示了復(fù)合模在同一位置布置多套凸、凹模的結(jié)構(gòu)特點。
這副模具的凸、凹模的布置方法是:上模部分裝有凸凹模2(它的外切刃口是墊圈甲的沖孔凸模同時又是墊圈乙的落料凸模,它的內(nèi)刃口是墊圈乙的沖孔凹模同時又是墊圈丙的落料凹模)和墊圈甲的落料凹模3、凸凹模18(它的外切刃口是墊圈丙的沖孔凸模同時又是墊圈丁的落料凸模,它的內(nèi)刃口是墊圈丁的沖孔凹模)。下模部分裝有凸凹模7(它的外切刃口是墊圈甲的落料凸模 ,它的內(nèi)刃口是墊圈甲的沖孔凹模同時又是墊圈乙的落料凹模)和墊圈丁的沖孔凸模11以及凸凹模14(它的外切口是墊圈乙的沖孔凸模同時又是墊圈丙的落料凸模,它的內(nèi)刃口是墊圈丙的沖孔凹模同時又是墊圈丁的落料凹模)。沖裁后,由上模推下的是墊圈甲、丙,還有墊圈丁的沖孔廢料,由下模頂出(在下模座下裝有彈頂裝置)的是墊圈乙和墊圈丁。關(guān)于其卸料方式已在上文中提及,就不再詳細介紹。
(四)、彈簧的選用和計算
1)卸料力前面已算出,總卸料力F卸=571.48N,根據(jù)模具結(jié)構(gòu)估計擬選用4個彈簧,計算每個彈簧擔(dān)負卸料力約為
F預(yù)=F卸/n
=571.48/4
=142.87N
即每個彈簧所承受的負荷力為142.87N。
2)由裝配結(jié)構(gòu)尺寸,求得彈簧自由高度
H0>凸模固定板厚度+彈簧壓縮量+凸模自由高度
H0>20+1.25+15=36.25mm
根據(jù)F預(yù)的大小,從圓柱螺旋壓縮彈簧表中可初選彈簧規(guī)格為外徑D=16mm,鋼絲直徑d=2.5mm,自由高度H0=50mm,彈簧最大工作載荷下的總變形量H許=17.5mm,有效圈數(shù)n=9.5,最大工作載荷F許=292N。
3)求出彈簧的預(yù)壓縮量:H預(yù)=F預(yù)H許/F許
=142.87×17.5/292
=8.56mm
則總壓縮量為:H總=H預(yù)+H工作+H修磨
=8.56+2+1+5
=16.56mm
總壓力F總=F預(yù)H總/ H預(yù)=142.87×16.56/8.56=276.4N
4)檢查所選彈簧的性能要求,即
總壓縮量H總=16.56mm<最大許可壓縮量H 許=17.5mm
總壓力F總=276.4N<最大工作負荷F許=292N
說明所選彈簧合適
最后選彈簧規(guī)格為:16mm×2.5mm×50mm
五、 選擇壓力機型號
因為模具閉合高度:
H閉=上模座厚+下模座厚+落料凹模厚+沖孔凸模長度+上墊板+下墊板-落料凹模與凸模的刃面高度差+板料厚度
=40+45+52+52+10+10-1+2
=210mm
根據(jù)設(shè)備載荷情況和模具的閉合高度,可選用J23-16型壓力機,該壓力機的最大裝模高度為220mm,最小裝模高度為160mm。
模具閉合高度滿足Hmin+10≤H閉≤Hmax-5,故認為合適。
六、主要零部件結(jié)構(gòu)與尺寸的選擇和確定
雖然為了能簡化模具設(shè)計制造工作,縮短周期,提高質(zhì)量,節(jié)約材料,降低成本,應(yīng)盡量采用標準件,但考慮到模具結(jié)構(gòu)的特殊性和合理性,還是不得不對零件某些方面進行必要的修改以滿足技術(shù)要求。
1)擋料銷:限定條料或卷料送進距離的定位銷件??紤]到該模具為帶有彈性卸料板的倒裝復(fù)合模,采用彈壓式活動擋料銷。此種擋料銷裝在彈壓卸料板上,沖壓時被壓入卸料板孔內(nèi),上?;爻虝r由彈簧、簧片將其頂起,以待下一次沖程時定位用。卸料板的擋料銷孔和擋料銷采用H8/d9基孔制間隙配合。
2)卸料裝置:卸料裝置的型式較多,它包括固定卸料板、活動卸料板、彈壓卸料板和廢料切刀等幾種。本模具采用彈壓卸料板作為卸料裝置。卸料板一般采用Q235或Q255鋼制造;在這里的卸料板宜用45鋼制造,熱處理硬度為28~30HRC。表面粗糙度應(yīng)達到Ra1.6~0.8μm。詳細尺寸見零件圖第11頁。
3)模柄選擇:中、小型沖模通過模柄將上模固定在壓力機的滑塊上。
由壓力機型號可知模柄孔直徑為40mm,深度為60mm,選旋入式模柄,通過螺紋與上模座連接,為防止松動,常用防轉(zhuǎn)螺釘緊固。選模柄規(guī)格為A40×90 GB2862.2—81·Q235,其旋入部分為30mm。因為在復(fù)合模的上模座中要加工打板孔15mm,所以旋入部分為40mm(模架厚度)-15mm(打板孔深)=25mm。即模柄的旋入部分要在原有基礎(chǔ)上再車去5mm,此時模柄總長度H=85mm。實際模柄規(guī)格為A40mm×85mm。
4)打料推桿尺寸:推桿直徑根據(jù)打料力選Φ12mm。
根據(jù)模具結(jié)構(gòu),推桿的長度為L桿>模柄總長=85mm
所以L桿=120mm。
5)凸凹模固定板:根據(jù)模具的結(jié)構(gòu),取固定板厚度為20mm。凸凹模固定板上的凸凹模安裝孔與凸凹模采用M7/h6基軸制過渡配合,凸凹模壓裝后端面要與固定板一起磨平。固定板的上、下表面粗糙度為Ra1.6~0.8μm,另一非基準面可適當(dāng)降低要求。固定板材料用45鋼制造,無需熱處理淬硬。
6)墊板:墊板的作用是直接承受和擴散凸模傳遞的壓力,以降低模座所受的單位壓力,防止模座被局部壓陷。該模具因為上下模座均分布著凸凹模,為降低模座所受的單位壓力,均需加上墊板。墊板外形尺寸詳見零件圖第2、8頁。其厚度取10mm。墊板材料為45鋼,淬火硬度為43~48HRC。墊板上、下表面應(yīng)磨平,表面粗糙度為Ra1.6~0.8μm,以保證平行度要求。
7)模架的選取:常用的標準模架是由上托、底座、導(dǎo)柱、導(dǎo)套等零件組成。按導(dǎo)柱的數(shù)量、在模架上固定位置的不同,可分為十二種。一般采用兩個導(dǎo)柱的模架。后側(cè)導(dǎo)柱模架可用于沖裁寬度大的條料,送料及操作比較方便。但由于導(dǎo)柱裝在一側(cè),沖壓時容易產(chǎn)生偏心力矩,使模具偏斜,影響模具壽命與工件質(zhì)量。因而適用于中等復(fù)雜程度及公差等級要求一般的中、小型工件。中間導(dǎo)柱模架在沖壓時不會因偏心距而引起模具的偏斜,有利于延長壽命,至于其缺點為條料寬度受導(dǎo)柱間的距離的限制,在對本工件加工中并不重要,所以本模具采用中間導(dǎo)柱形式。
由凹模周界尺寸D=50mm+2×35mm=120mm,選I級精度的中間導(dǎo)柱圓形模架。
模架規(guī)格:160mm×(180~220)mm I [GB/T2851.6—1990《沖模滑動導(dǎo)向模架 中間導(dǎo)柱圓形模架》]
8)螺釘:選M10mm螺釘,其長度根據(jù)模具結(jié)構(gòu)定。
9)圓柱銷:選Φ8mm來固定凹模,選Φ6mm來連接卸料板,長度由模具結(jié)構(gòu)定。
七、繪制模具總裝圖
原理說明:
本模具為多墊圈復(fù)合模。
該模具一次沖出四只橡膠墊圈,具有生產(chǎn)效率高和少廢料的特點。
模具由凸模11、凹模3和凸凹模2、7、14、18等組成。
頂板5、12、圓銷6和彈壓卸料板13一起組成下頂件器,借彈簧24之力將工件頂出。
頂板15、16、17與圓銷4連在一起組成上頂件器,借打棒20之力將工件和廢料打下。
八、 繪制主要非標準零部件圖
(見圖紙第2~18頁)
十、結(jié)束語
歷時兩個多月的畢業(yè)設(shè)計,其目的在于綜合運用本專業(yè)所學(xué)課程的理論和生產(chǎn)實際知識,進行一次設(shè)計工作的實際訓(xùn)練,從而培養(yǎng)和提高獨立工作的能力,鞏固和擴充課堂上所學(xué)到的知識,掌握一般設(shè)計的方法和步驟等基本技能,進一步熟練計算、繪圖、查閱設(shè)計資料和手冊,熟悉標準規(guī)范。
沖壓模具是冷沖壓工藝必不可少的工藝裝備,沖壓模具設(shè)計的好壞,水平的高低,將直接影響產(chǎn)品質(zhì)量、成本、生產(chǎn)效率與操作者的安全。
復(fù)合模是沖壓模具的一種,它對提高生產(chǎn)效率、降低成本、提高質(zhì)量和實際沖壓自動化等方面有著非?,F(xiàn)實的意義。
這付多墊圈復(fù)合模的結(jié)構(gòu)比較復(fù)雜,模具制造精度高,這對模具設(shè)計者來說,需要考慮的方面很多,尤其是模具各部分結(jié)構(gòu)的設(shè)計。
在本次設(shè)計得到了指導(dǎo)老師的幫助和支持,特在此表示衷心的感謝!
由于水平有限,此模具設(shè)計難免存在著一些缺點和錯誤,敬請各位老師批評指教。
參考文獻
高鴻庭、劉建超主編:《冷沖模設(shè)計及制造》,機械工業(yè)出版社
華玉培、李恒權(quán)主編:《冷沖壓及模具設(shè)計》,山東科學(xué)技術(shù)出版社
丁松聚主編:《冷沖模設(shè)計》,機械工業(yè)出版社
陳劍鶴主編:《冷沖壓工藝與模具設(shè)計》,機械工業(yè)出版社
王芳主編:《冷沖壓模具設(shè)計指導(dǎo)》,機械工業(yè)出版社
王孝培主編:《沖壓設(shè)計資料》,機械工業(yè)出版社
南京機械高等??茖W(xué)校——陳于萍主編:《互換性與測量技術(shù)基礎(chǔ)》,機械工業(yè)出版社
《冷沖壓模具設(shè)計》,上海市儀表電訊工業(yè)局
《冷沖壓模具設(shè)計》,第四機械工業(yè)部標準化研究所
《機械制圖》,高等教育出版社
《機械設(shè)計基礎(chǔ)》,江蘇科學(xué)出版社
《沖模設(shè)計手冊》,機械工業(yè)出版社
25
General all-steel punching die’s punching accuracy
Author:John J. Craig
Accuracy of panel punching part is display the press accuracy of the die exactly. But the accuracy of any punching parts’ linear dimension and positional accuracy almost depend on the blanking and blanking accuracy,. So that the compound mould of compound punching’s accuracy, is typicalness and representation in the majority.
Analyse of the die’s accuracy
For the analyse of pracyicable inaccuracy during production of dies to inactivation, we could get the tendency when it is augmentation in most time. From this we could analyse the elements. When the new punch dies pt into production to the first cutter grinding, the inaccuracy produced called initial error; if the die grinding more than twenty times, until it’s discard, the inaccuracy called conventional error; and before the dies discard, the largest error of the last batch permit, called limiting error. at job site, the evidence to confirm life of sharpening is the higher of the blanking, punched hole or punched parts. Because all finished parts had been blanked ,so it is especially for the compound dies. Therefore, the analyse of burr and measurement is especially important when do them as enterprise standardization or checked with <>.
The initial error usually is the minimal through the whole life of die. Its magnitude depend on the accuracy of manufacture, quality, measure of the punching part, thickness of panel, magnitude of gap and degree of homogeneity. The accuracy of manufacture depend on the manufacture process. For the 1 mm thicked compound punching part made in medium steel, the experimental result and productive practice all prove that the burr of dies which produced by spark cutting are higher 25%~~30% than produced by grinder ,NC or CNC. The reason is that not only the latter have more exact machining accuracy but also the value of roughness Ra is less one order than the formmer, it can be reached 0.025μm. Therefore, the die’s initial blanked accuracy depends on the accuracy of manufacture, quality and so on.
The normal error of the punch die is the practicable error when the fist cutter grinding and the last cutter grinding before the die produce the last qualified product. As the increase of cutter grinding, caused the measure the nature wear of the dies are gradual increasing, the error of punching part increase also, so the parts are blew proof. And the die will be unused. The hole on the part and inner because the measure of wear will be small and small gradually, and its outside form will be lager in the same reason. Therefore, the hole and inner form in the part will be made mould according to one-way positive deviation or nearly equal to the limit max measure. In like manner, the punching part’s appearance will be made mould according to one-way negative deviation or nearly equal to limit mini measure. For this will be broaden the normal error, and the cutter grinding times will be increased, the life will be long.
The limit error in punching parts are the max dimension error which practicable allowed in the parts with limit error. This kind of parts usually are the last qualified products before the die discard.
For the all classes of dies, if we analyse the fluctuate, tendency of increase and decrease and law which appeared in the die’s whole life, we will find that the master of the error are changeless; the error that because the abrade of the cutter and impression will be as the cutter grinding times increased at the same time. And that will cause the error oversize gradually; and also have another part error are unconventional , unforeseen. Therefore, every die’ s error are composed of fixed error, system error, accident error and so on.
At the whole process when the New punching die between just input production to discard, the changeless master error that in qualified part are called fixed error. It’s magnitude is the deviation when the die production qualified products before the first cutter grinding. Also is the initial error, but the die have initial punching accuracy at this time. Because of the abrade of parts, the die after grinding will be change the dimension error. And the increment of deviation will oversize as the times of cutter grinding. So the punching accuracy after cutter grinding also called “grinding accuracy” and lower tan initial accuracy. The fixed error depend on the elements factor as followed :
1. the material , sorts, structure, (form) dimension, and thick of panel
the magnitude of punching gap and degree of homogeneity are have a important effect for the dimension accuracy. Different punching process, material, thick of panel, have completely different gap and punching accuracy. A gear H62 which made in yellow brass with the same mode number m=0.34, 2mm thick and had a center hole, when the gap get C=0.5%t (single edge) , and punched with compound punching die, and the dimension accuracy reached IT7, the part have a flat surface ,the verticality of tangent plane reached 89.5°, its roughness Ra magnitude are 12.5μm, height of burr are 0.10mm; and the punching part are punched with progressive die, the gap C=7%t (single edge) , initial accuracy are IT11, and have an more rough surface, even can see the gap with eyes. In the usual situation, flushes a material and its thickness t is theselection punching gap main basis. Once the designation gap haddetermined flushes the plane size the fixed error main body; Flushesthe structure rigidity and the three-dimensional shape affects itsshape position precision.
2. punching craft and molder structure type
Uses the different ramming craft, flushes a precision and the fixederror difference is really big. Except that the above piece gearexample showed, the essence flushes the craft and ordinary punching flushes a precision and the fixed error differs outside a magnitude,even if in ordinary punching center, uses the different gap punching, thefixed error difference very is also big. For example material thickt=1.5mm H62 brass punching, selects C <= the 40%t unilateral I kind ofsmall gap punching compared to select C <= 8%t (unilaterally) III kindof big gap punching, will flush a fixed error to enlarge 40% ~ 60%, theprecision at least will fall a level. Side in addition, whether thereis picks builds a row of type side, flushes a error to have far to bebigger than has builds a row of type to flush. Side not builds a rowof type to flush. Side not builds a row of type to flush a precisionto be lower than the IT12 level side, but most has builds a row oftype to flush a precision in IT11 between ~ IT9 level, material thickt > 4mm flushes, the size precision can lower some. Different die’s structure type, because is suitable the rammingmaterial to be thick and the manufacture precision difference, causesto flush a fixed error to have leaves. Compound die center, multi-locations continuous type compound die because flushes continuously toduplicate the localization to add on the pattern making error to bebigger, therefore it flushes a fixed error compound punching die to wantcompared to the single location Big 1 ~ 2 levels
3. the craft of punching die’s manufacture
the main work of punching die namely are raised, the concave moldprocessing procedure, to operates on the specification not to behigh, can time form a more complex cavity. But its processing surfaceapproximately is thick > 0.03 ~ 0.05mm is the high temperatureablation remaining furcated austenite organization, degree ofhardness may reach as high as HRC67 ~ 70, has the micro crack, easilywhen punching appears broke the cutter or flaking. The Italian CorradaCorporation''s related memoir called "the line cut the processing contruction to have the disadvantageous influence to the superficialgold, in fact already changed the gold contruction. We must use theJin''gang stone powder to grind or the numerical control continual pathcoordinates rub truncate (cut to line) to make the precision work ". In recent years country and so on Switzerland and Japan, has conductedthe thorough research to the electrical finishing equipment and abigger improvement, makes function complete high accuracy NC and theCNC line cutter, the processing precision may reach ±0.005 ~ 0.001mm,even is smaller. The processing surface roughness Ra value can achieve0.4 mu m. According to the recent years to the domestic 12 productionlines cutter factory investigation and study, the domesticallyproduced line cutter processing precision different factory differentmodel line cutter might reach ±0.008 ~ ±0.005mm, generally all in±0.01mm or bigger somewhat, was individual also can achieve±0.005mm, the processing surface roughness Ra value was bigger than1.6μm. However, the electrical finishing ablation metal surface thus the change and the damage machined surface mental structure character can not change, only if with rubs truncates or other ways removes this harmful level. Therefore, merely uses electricity machining, including the spark cutting and the electricity perforation, achieves with difficulty punching, especially high accuracy, high life punching die to size precision and work components surface roughness Ra value request.
With precisely rubs truncates the law manufacture punching die, specially makes the high accuracy, the high life punching die, such as: Thin material small gap compound punching die, multi- locations continuous type compound die and so on, has the size precision high, the work component smachined surface roughness Ra value is small, the mold life higher characteristic. Its processing craft at present changed the electrical fire by the past ordinary engine bed rough machining spark cutting or the electricity puncher rough machining, finally precisely rubs truncates, also from takes shape rubs, optics curve rubs, the manual grid reference rubs gradually filters the continual path grid reference to rub and NC and the CNC continual path grid reference rubs, Processing coarseness may reach ±0.001 ~ 0.0005mm, the processing surface roughness Ra value may reach 0.1 ~ 0.025 mu m. Therefore, with this craft manufacture the die , regardless of the size precision, the work components surface roughness, all can satisfy die, each kind of compound request, the die is especially higher than the electrical finishing craft manufacture scale.
4. gap size and degree of homogeneity
the flange and other sheet forming sgene rally all must first punching (fall material) the plate to launch the semi finished materials, after also has the forming to fall the material, the incision obtains the single end product to flush. Therefore punching the work, including is commonly used punching hole, the margin, cut side and so on, regarding each kind of sheet pressing partall is necessary. Therefore punching the gap to flushes a out form in chprecision to have the decisive influence. punching the gap small and is even, may cause punching the size gain high accuracy. Regarding drawability, is curving and so on mould, the gap greatly will decide increases flushes the oral area size error and the snapping back. The gapnon-uniformity can cause to flush a burr enlarges and incurs cutting edge the non-uniform attrition.
5. ramming equipment elastic deformation In the ramming process
After the punch press load bearing can have the certain elastic deformation. Although this kind of distortion quantity according to flushes the pressure the size to change also to have the obvious directivity, but on the pressing part, mainly is to has the volume ramming archery target stamping, embosses, the equalization, the pressure is raised, the wave, flushes crowds, the shape, the flange, hits flatly, thinly changes draw ability and so on the craft work punching forming flushes, has the significant influence to its ramming aspect size precision
From:<>
收藏