版權(quán)說(shuō)明:本文檔由用戶(hù)提供并上傳,收益歸屬內(nèi)容提供方,若內(nèi)容存在侵權(quán),請(qǐng)進(jìn)行舉報(bào)或認(rèn)領(lǐng)
文檔簡(jiǎn)介
1、<p> General all-steel punching die’s punching accuracy</p><p> Accuracy of panel punching part is display the press accuracy of the die exactly. But the accuracy of any punching parts’ linear dimensi
2、on 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.</p><p> Analys
3、e of the die’s accuracy </p><p> 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 analy
4、se 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 calle
5、d conventional error; and before the dies discard, the largest error of the last batch permit, called limit</p><p> The initial error usually is the minimal through the whole life of die. Its magnitude depe
6、nd 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 thicke
7、d 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 produc</p><p> The nor
8、mal 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
9、 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
10、 and small gradually, and its outside form will be la</p><p> The limit error in punching parts are the max dimension error which practicable allowed in the parts with limit error. This kind of parts usuall
11、y are the last qualified products before the die discard.</p><p> 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,
12、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 over
13、size gradually; and also have another part error are unconventional , unforeseen. Therefore, every die’ s error are composed of fixed error,</p><p> 1. fixed error </p><p> At the whole proces
14、s 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
15、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 inc
16、rement of deviation will oversize as the </p><p> (1) the material , sorts, structure, (form) dimension, and thick of panel</p><p> the magnitude of punching gap and degree of homogeneity are
17、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 numb
18、er 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 tangen
19、</p><p> (2) punching craft and molder structure type</p><p> Uses the different ramming craft, flushes a precision and the fixederror difference is really big. Except that the above piece gea
20、rexample 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 erro
21、r 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 comp</p><p> (3) the craft of punching die’s manufacture&
22、lt;/p><p> 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 surface
23、approximately 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 bro
24、ke the cutter or flaking. The Italian CorradaCorporation''s related memoir called "th</p><p> With precisely rubs truncates the law manufacture punching die, specially makes the high accuracy,
25、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
26、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</p><p> (4) gap size and
27、 degree of homogeneity </p><p> 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
28、 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 nec
29、essary. Therefore punching the gap to flushes a out form in chprecision to have the decisive influence. pu</p><p> (5) ramming equipment elastic deformation In the ramming process </p><p> Aft
30、er 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 pr
31、essing 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
32、so on the craft work punching forming flushes, has the si</p><p> 普通全鋼沖模的沖壓精度分析</p><p> 板料沖壓件的精度準(zhǔn)確顯示出其沖模的沖壓精度。而任何沖件的線性尺寸精度與形位精度主要取決于沖模沖裁和立體成形沖壓件展開(kāi)平毛坯的落料精度。因此,多工步復(fù)合沖壓的單工位復(fù)合模、多工位連續(xù)模的沖壓精度,在普通沖壓的眾
33、多種類(lèi)與不同結(jié)構(gòu)的沖模中,最具典型性和代表性。</p><p><b> 沖模的沖壓精度分析</b></p><p> 對(duì)沖模投產(chǎn)至失效報(bào)廢各個(gè)時(shí)期沖件的實(shí)際誤差分析,可以看出其增大的時(shí)期及趨向,從而分析其增大的因素。新沖模投產(chǎn)至第一次刃磨前沖制沖件的誤差即所謂的初始誤差;沖模經(jīng)過(guò)20次左右刃磨至失效報(bào)廢前沖制的沖件誤差稱(chēng)之為常規(guī)誤差;而沖模失效報(bào)廢前沖制的最后一
34、批合格沖件的允許最大誤差稱(chēng)之為極限誤差。在現(xiàn)場(chǎng),確定沖模刃磨壽命的依據(jù)是沖件沖孔與落料的毛刺高度。由于任何成形件都具有沖裁作業(yè)(毛坯落料或沖孔),對(duì)于復(fù)合模尤為如此。所以,沖件毛刺高度的觸模檢查和測(cè)量并按企業(yè)標(biāo)準(zhǔn)或JB4129-85《沖壓件毛刺高度》對(duì)照檢測(cè)就顯得十分重要。</p><p> 沖模的初始誤差通常是沖模整個(gè)壽命中沖件誤差最小的。其大小主要取決于沖模的制造精度與質(zhì)量及沖件尺寸、料厚以及間隙值大小與均
35、勻度。沖模的制造精度及質(zhì)量又取決于制模工藝。對(duì)于料厚t≤1mm的中碳鋼復(fù)合沖裁模沖件,實(shí)驗(yàn)結(jié)果與生產(chǎn)實(shí)踐都證明,電火花線切割制造的沖模沖件毛刺高度比用成型磨或NC與CNC連續(xù)軌跡座標(biāo)磨即精密磨削工藝制造的沖模沖件要高25%~30%。這是因?yàn)楹笳卟粌H加工精度高,而且加工面粗糙度Ra值要比前者小一個(gè)數(shù)量級(jí),可達(dá)到0.025μm。因此,沖模的制造精度與質(zhì)量等因素決定了沖模的初始沖壓精度,也造就了沖件的初始誤差。</p><
36、p> 沖件的常規(guī)誤差是沖模經(jīng)第一次刃磨到最后一次刃磨后沖出最后一個(gè)合格沖件為止,沖件實(shí)際具有的誤差。隨著刃磨次數(shù)的增加,刃口的自然磨損而造成的尺寸增量逐漸加大,沖件的誤差也隨之加大。當(dāng)其誤差超過(guò)極限偏差時(shí),沖件就不合格,沖模也就失效報(bào)廢。///////沖件上孔與內(nèi)形因凸模磨損尺寸會(huì)逐漸變?。黄渫庑温淞铣叽鐣?huì)因凹模磨損而逐漸增大。所以,沖件上孔與內(nèi)形按單向正偏差標(biāo)允差并依接近或幾乎等于極限最大尺寸制模。同理,沖件外形落料按單向負(fù)偏
37、差標(biāo)注允差并依接近或幾乎等于極限最小尺寸制模。這樣就使沖件的常規(guī)誤差范圍擴(kuò)大,沖模可刃磨次數(shù)增加,模具壽命提高。</p><p> 沖件的極限誤差是具有極限偏差的沖件所具有的實(shí)際允許的最大尺寸誤差。這類(lèi)沖件通常是在沖模失效報(bào)廢前沖制的最后一批合格沖件。</p><p> 對(duì)各類(lèi)沖模沖件誤差在沖模整個(gè)壽命中出現(xiàn)的波動(dòng)、增減趨向及規(guī)律等進(jìn)行全面分析便可發(fā)現(xiàn):沖件誤差的主導(dǎo)部分是不變的;因刃
38、口或型腔的自然磨損而出現(xiàn)的誤差增量隨沖模刃磨沖數(shù)增加而使這部分誤差逐漸加大;還有部分誤差的增量是非常規(guī)的、不可預(yù)見(jiàn)的。所以,各類(lèi)沖模沖件誤差是由因定誤差、漸增誤差、系統(tǒng)誤差及偶發(fā)誤差等幾部分綜合構(gòu)成。</p><p><b> 1、固定誤差</b></p><p> 新沖模在指定的沖壓設(shè)備上投入使用至失效報(bào)廢的整個(gè)(總)壽命過(guò)程中,其合格沖件誤差的主導(dǎo)部分固定不變
39、即所謂固定誤差。其大小就是新沖模第一次刃磨前沖制的合格沖件的偏差,也即沖模的初始誤差,而此時(shí)的沖模具有初始沖壓精度。刃磨后的沖模,因其工作零件(凸、凹模)磨損而改變尺寸誤差,使沖件識(shí)差增量隨刃磨次數(shù)增加而逐漸加大,故沖模刃磨后的沖壓精度亦稱(chēng)“刃磨精度”比其初始精度要低。沖模沖件的固定誤差取決于以下各要素:</p><p> ?。?)沖件的材料種類(lèi)、結(jié)構(gòu)(形狀)尺寸及料厚</p><p>
40、 沖裁間隙的大小及其均勻度對(duì)沖裁件的尺寸精度有決定性的影響。不同沖裁工藝、不同材料種類(lèi)與不等料厚,間隙相差懸殊,沖壓精度差異很大。同一種模數(shù)m=0.34的2mm的料厚、中心有孔的H62黃銅材料片齒輪復(fù)合模沖件,當(dāng)取間隙C=0.5%t(單邊),用復(fù)合精沖模沖制,沖件尺寸精度達(dá)到IT7級(jí),沖件平直無(wú)拱彎,沖切面垂直度可達(dá)89.5°,其表面粗糙Ra值為0.2μm;而用普通復(fù)合模沖制,間隙C=5%t(單邊),沖件初始誤差亦即沖模的初始
41、沖壓精度為1T9級(jí),沖切面粗糙度Ra值為12.5μm,毛刺高度為0.10mm;還是這個(gè)沖件用連續(xù)模沖制,間隙C=7%t(單邊),初始沖件精度為IT11級(jí),沖切面更粗糙,甚至有肉眼可見(jiàn)的臺(tái)階。通常情況下,沖件材料及其厚度t是選取沖裁間隙的主要依據(jù)。一旦選定間隙就確定了沖件的平面尺寸的固定誤差的主體;沖件結(jié)構(gòu)剛度及立體形狀則影響其形位精度。</p><p> ?。?)沖壓工藝及沖模結(jié)構(gòu)類(lèi)型</p>&l
42、t;p> 采用不同的沖壓工藝,沖件的精度及固定誤差相差甚大。除上述片齒輪實(shí)例說(shuō)明,精沖工藝與普通沖裁的沖件精度與固定誤差相差一個(gè)數(shù)量級(jí)之外,即便在普通沖裁中,采用不同間隙沖裁,固定誤差相差也很大。例如料厚t=1.5mm的H62黃銅沖裁件,選用C≤40%t單邊Ⅰ類(lèi)小間隙沖裁比選用C≤8%t(單邊)Ⅲ類(lèi)大間隙沖裁,沖件固定誤差將加大40%~60%,精度至少降一級(jí)。此外,采有無(wú)搭邊排樣,沖件的誤差要遠(yuǎn)大于有搭邊排樣沖件。無(wú)搭邊排樣沖件
43、。無(wú)搭邊排樣沖件的精度低于IT12級(jí),而多數(shù)有搭邊排樣的沖件精度在IT11~I(xiàn)T9級(jí)之間,料厚t>4mm的沖件,尺寸精度會(huì)更低一些。</p><p> 不同沖模結(jié)構(gòu)類(lèi)型,由于適用沖壓料厚及制造精度的差異,導(dǎo)致沖件的固定誤差有別。復(fù)合模中,多工位連續(xù)式復(fù)合模由于沖件連續(xù)重復(fù)定位加上制模誤差較大,故其沖件的固定誤差比單工位復(fù)合沖裁模要 </p><p><b> 大1~2級(jí)。&l
44、t;/b></p><p><b> ?。?)沖模制造工藝</b></p><p> 沖模主要工作零件即凸、凹模的加工程序,對(duì)操作上的技術(shù)要求不高,能夠一次成形較復(fù)雜的模腔。但其加工表面約厚>0.03~0.05mm為高溫?zé)g的殘余樹(shù)枝狀?yuàn)W氏體組織,硬度可高達(dá)HRC67~70,有顯微裂紋,容易在沖裁時(shí)出現(xiàn)崩刃或剝落。意大利Corrada公司的有關(guān)研究報(bào)告稱(chēng)“線切
45、割加工對(duì)表面金相結(jié)構(gòu)產(chǎn)生不利的影響,實(shí)際上已經(jīng)改變了金相結(jié)構(gòu)。我們必須用金剛石粉研磨或數(shù)控連續(xù)軌跡坐標(biāo)磨削(對(duì)線切割件)作精加工”。近年來(lái)瑞士和日本等國(guó),對(duì)電加工設(shè)備進(jìn)行了深入的研究和較大的改進(jìn),制造出功能齊全的高精度NC和CNC線切割機(jī),加工精度可達(dá)±0.005~0.001mm,甚至更小。加工表面粗糙度Ra值能達(dá)到0.4μm。根據(jù)近年對(duì)國(guó)內(nèi)12家生產(chǎn)線切割機(jī)工廠的調(diào)研,國(guó)產(chǎn)線切割機(jī)加工精度各別廠家的各別型號(hào)線切割機(jī)可達(dá)
46、77;0.008~±0.005mm,一般都在±0.01mm或更大一些,個(gè)別也能達(dá)到±0.005mm,加工表面粗糙度Ra值均大于1.6μm。然而,電加工燒蝕金屬表面從而改變和損壞加工面金相結(jié)構(gòu)的特性不會(huì)改變,除非用磨削或其他加工法去除這一有害層。所以,僅僅用電加工法,包括電火花線切割與電穿孔,難以達(dá)到?jīng)_模</p><p> 用精密磨削法制造沖模,特別是制造高精度、高壽命沖模,諸如:薄
47、料小間隙復(fù)合沖裁模、多工位連續(xù)式復(fù)合模等,具有尺寸精度高、工作零件加工面粗糙度Ra值小、模具壽命高等特點(diǎn)。其加工工藝目前已由過(guò)去的普通機(jī)床粗加工改為電火花線切割或電穿孔機(jī)粗加工,最后精密磨削,也由成型磨、光學(xué)曲線磨、手動(dòng)座標(biāo)磨逐步過(guò)濾到連續(xù)軌跡座標(biāo)磨及NC與CNC連續(xù)軌跡座標(biāo)磨,加工粗度可達(dá)±0.001~0.0005mm,加工表面粗糙度Ra值可達(dá)0.1~0.025μm。所以,用該工藝制造的沖模,無(wú)論尺寸精度、工作零件表面粗糙度
48、,都能滿(mǎn)足沖模,尤其各種復(fù)合模的要求,比電加工工藝制造的沖模高一個(gè)檔次。</p><p> (4)間隙的大小與均勻度</p><p> 拉深、彎曲、翻邊及其他板料成形件一般都要先沖裁(落料)出平板展開(kāi)毛坯,也有成形后落料、切開(kāi)得到單個(gè)成品沖件。故沖裁作業(yè),包括常用的沖孔、切口、切邊等,對(duì)于每種板料沖壓件都是必要的。所以沖裁間隙對(duì)沖件的外廓尺寸精度有決定性的影響。沖裁間隙小而均勻,可使沖
49、裁尺寸獲取更高精度。對(duì)于拉深、彎曲等成形模,間隙大定將增大沖件口部尺寸誤差及回彈。間隙不均勻會(huì)使沖件毛刺加大并招致刃口的不均勻磨損。</p><p> ?。?)沖壓設(shè)備的彈性變形</p><p> 在沖壓過(guò)程中,沖床承載后會(huì)產(chǎn)生一定的彈性變形。雖然這種變形量依沖壓力的大小變化且具有明顯的方向性,但就沖壓件,主要是對(duì)具有體積沖壓性質(zhì)的壓印、壓花、校平、壓凸、起波、沖擠、鐓形、翻邊、鐓粗、打
溫馨提示
- 1. 本站所有資源如無(wú)特殊說(shuō)明,都需要本地電腦安裝OFFICE2007和PDF閱讀器。圖紙軟件為CAD,CAXA,PROE,UG,SolidWorks等.壓縮文件請(qǐng)下載最新的WinRAR軟件解壓。
- 2. 本站的文檔不包含任何第三方提供的附件圖紙等,如果需要附件,請(qǐng)聯(lián)系上傳者。文件的所有權(quán)益歸上傳用戶(hù)所有。
- 3. 本站RAR壓縮包中若帶圖紙,網(wǎng)頁(yè)內(nèi)容里面會(huì)有圖紙預(yù)覽,若沒(méi)有圖紙預(yù)覽就沒(méi)有圖紙。
- 4. 未經(jīng)權(quán)益所有人同意不得將文件中的內(nèi)容挪作商業(yè)或盈利用途。
- 5. 眾賞文庫(kù)僅提供信息存儲(chǔ)空間,僅對(duì)用戶(hù)上傳內(nèi)容的表現(xiàn)方式做保護(hù)處理,對(duì)用戶(hù)上傳分享的文檔內(nèi)容本身不做任何修改或編輯,并不能對(duì)任何下載內(nèi)容負(fù)責(zé)。
- 6. 下載文件中如有侵權(quán)或不適當(dāng)內(nèi)容,請(qǐng)與我們聯(lián)系,我們立即糾正。
- 7. 本站不保證下載資源的準(zhǔn)確性、安全性和完整性, 同時(shí)也不承擔(dān)用戶(hù)因使用這些下載資源對(duì)自己和他人造成任何形式的傷害或損失。
最新文檔
- 地質(zhì)外文文獻(xiàn)翻譯中英文對(duì)照
- 成本控制中英文對(duì)照外文翻譯文獻(xiàn)
- 畢業(yè)論文外文翻譯(中英文)
- 成本控制中英文對(duì)照外文翻譯文獻(xiàn)
- 外文翻譯-中英文對(duì)照avr單片機(jī)
- 外文翻譯-中英文.doc
- 外文翻譯-中英文.doc
- 沖壓模具設(shè)計(jì)畢業(yè)外文翻譯@中英文翻譯@外文文獻(xiàn)翻譯
- 新能源汽車(chē)中英文對(duì)照外文翻譯文獻(xiàn)
- 外文翻譯-中英文.doc
- 機(jī)械鉆床外文翻譯論文中英文
- 外文翻譯---工程造價(jià)管理前沿(中英文對(duì)照)
- 外文翻譯-工程造價(jià)管理淺論(中英文對(duì)照)
- 新能源汽車(chē)中英文對(duì)照外文翻譯文獻(xiàn)
- 外文翻譯-中英文.doc
- 外文翻譯中英文.doc
- 外文翻譯-中英文.doc
- 外文翻譯-中英文.doc
- 中英文對(duì)照翻譯---表面活性
- 外文翻譯中英文.doc
評(píng)論
0/150
提交評(píng)論