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河 北 建 筑 工 程 學(xué) 院
本科畢業(yè)設(shè)計(jì)(論文)
題
目
前板連續(xù)模設(shè)計(jì)及沖壓工藝分析
學(xué)科專業(yè) 機(jī)械設(shè)計(jì)制造及其自動(dòng)化
班 級(jí) 機(jī) 094
姓 名 劉 松
指導(dǎo)教師 孫 長(zhǎng) 山
輔導(dǎo)教師
摘 要
模具是工業(yè)生產(chǎn)的基礎(chǔ)工藝裝配,廣泛應(yīng)用于機(jī)械、汽車、電子通訊、家電等行業(yè),其中有80%以上的產(chǎn)品零件均通過(guò)模具生產(chǎn)而成。在國(guó)際上,模具又有“工業(yè)之母”之稱。模具分為冷沖壓模具、熱鍛模具、塑料模具、鑄造模具、橡校模具和玻璃模具等。其中冷沖壓模具在各種模具中所占比重最多,占整個(gè)模具市場(chǎng)的60%以上,具有廣泛的發(fā)展前景。
冷沖壓模具是在室溫下,借助于設(shè)備提供的壓力,利用模具使板料發(fā)生分離成塑性變形的一種加工方法。加工對(duì)象主要是金屬或非金屬的板料。
本設(shè)計(jì)是對(duì)給定的模具產(chǎn)品圖進(jìn)行沖壓工藝分析和連續(xù)模設(shè)計(jì),在綜合考慮了加工產(chǎn)品的經(jīng)濟(jì)性、零件的沖壓工藝性以及復(fù)雜程度和精確度等諸多因素的基礎(chǔ)上進(jìn)行沖壓工藝分析與計(jì)算的,并提出了合理的工藝方案和結(jié)構(gòu)形式;最后,結(jié)合產(chǎn)品的工藝及現(xiàn)有加工方法合理設(shè)計(jì)連續(xù)模排樣方案及加工方法最終達(dá)到省時(shí)省料、節(jié)約資源的目的。本設(shè)計(jì)介紹了模具設(shè)計(jì)中的排樣與送料方式和卸料與導(dǎo)向方式,討論了主要工作件間隙的確定和刃口尺寸及沖壓力的計(jì)算,并選擇合適的壓力機(jī),設(shè)計(jì)中主要對(duì)模具工作部分尺寸進(jìn)行計(jì)算和主要零部件的設(shè)計(jì)以及加工工藝的制定。
總而言之沖壓模的加工生產(chǎn)效率高,加工成本低,材料利用率高,產(chǎn)品的一致性好,制件質(zhì)量符合生產(chǎn)要求,且操作簡(jiǎn)單。
關(guān)鍵詞:前板 沖壓 工藝分析 連續(xù)模
Abstract
Mold is the basis of industrial production assembly process is widely used in machinery, automobile, telecommunications, home appliances and other industries, including more than 80% of the product parts are made through the mold production. At the international level, mold and "Mother of industry" called. Is divided into cold stamping die mold, forging mold, plastic mold, die casting, rubber mold school, such as mold and glass. One cold stamping die mold in a variety of the largest share, accounting for the entire mold more than 60% of the market, has a broad development prospects.
Cold stamping die is at room temperature, the pressure through the use of equipment, the use of sheet metal dies so that the separation took placeinto a plastic deformation process. Processing object is a metallic or non-metallic sheet.
The design of stamping process analysis and die design for a given moldproducts, in comprehensive consideration of the stamping process of economy,parts processing products and complexity and accuracy factors on stamping process analysis and calculation, and put forward the reasonable process scheme and structure; finally, combined with the product of the process andthe existing processing method of rational design of progressive die layoutand processing method of saving time and material, reach the purpose of saving resources. This design introduced the mold design of nesting and feeding and discharging and guiding mode, the main pieces of determining clearance and edge size and blanking force calculation are discussed,and select the appropriate machine design, design of the main working parts of die size calculation and main parts and processing technology .
All in all, the production of Die efficient processing, low processing costs, material utilization high, the product of good consistency, the product quality is suit for the production needs, and easy to operate.
Key words:foreplate ,stamping,analysis of manufacturing ,modulus of continuity
目 錄
第1章 前言·················································································1
1.1 沖壓的概念、特點(diǎn)及應(yīng)用······························································1
1.2 沖壓的基本工序及模具································································2
1.3 連續(xù)模介紹·············································································3
1.4 連續(xù)模結(jié)構(gòu)分析········································································3
1.5 連續(xù)模設(shè)計(jì)要點(diǎn)········································································4
第2章 連續(xù)模設(shè)計(jì)過(guò)程··································································8
2.1 沖件工藝性分析········································································8
2.1.1 沖裁件結(jié)構(gòu)工藝性···································································8
2.1.2 沖裁件的精度和毛刺································································8
2.2 工藝方案的設(shè)定········································································9
2.3 間隙的含義及間隙值的選擇·························································10
2.3.1 沖裁間隙分析·······································································10
2.3.2 間隙值的選擇·······································································11
2.4 沖壓加工工序及排樣圖設(shè)計(jì)·························································11
2.5 凸模、凹模尺寸的計(jì)算·······························································12
2.5.1 外形尺寸的計(jì)算····································································12
2.5.2 內(nèi)形尺寸的計(jì)算····································································13
第3章 落料件凸凹模尺寸計(jì)算過(guò)程·················································15
3.1 刃口尺寸計(jì)算·········································································15
3.2 沖孔部分凸凹模尺寸計(jì)算····························································19
第4章 沖壓力的計(jì)算····································································20
4.1 沖裁件的力學(xué)性能分析·······························································20
4.2 沖裁件沖裁力的計(jì)算·································································20
4.3 沖裁件卸料力的計(jì)算·································································21
4.4 沖裁件推件力的計(jì)算·································································21
4.5 沖裁件頂件力的計(jì)算·································································22
4.6 沖裁件彎曲力的計(jì)算·································································22
4.7 沖裁件壓力中心的計(jì)算·······························································23
第5章 排樣計(jì)算··········································································25
第6章 模具結(jié)構(gòu)設(shè)計(jì)····································································29
6.1 模具的總體結(jié)構(gòu)介紹·································································29
6.2 主要零部件設(shè)計(jì)·······································································29
6.2.1 壓力機(jī)的選擇·······································································29
6.2.2 模架的選擇·········································································31
6.2.3 上、下模座的選擇·································································32
6.2.3.1 上模座的設(shè)計(jì)選擇·······························································33
6.2.3.2 下模座的設(shè)計(jì)選擇·······························································34
6.2.4 凹、凸模的設(shè)計(jì)選擇·······························································35
6.2.4.1 凸模設(shè)計(jì)選擇····································································35
6.2.4.2 凹模的設(shè)計(jì)選擇·································································36
6.2.5 模柄的設(shè)計(jì)與選擇·································································37
6.2.6 導(dǎo)柱和導(dǎo)套的選擇·································································38
6.2.7 卸料裝置的設(shè)計(jì)與選擇····························································39
6.2.8 頂料裝置的選擇與計(jì)算····························································41
6.2.9 擋料和導(dǎo)正裝置的設(shè)計(jì)與選擇····················································42
第7章 其他零部件的設(shè)計(jì)與選擇····················································43
7.1 卸料裝置中彈性元件的計(jì)算·························································43
7.1.1 卸料塊的設(shè)計(jì)·······································································43
7.1.2 彈性元件橡膠的設(shè)計(jì)與選擇·······················································43
7.2 卸料板的設(shè)計(jì)與選擇·································································46
7.3 墊板的設(shè)計(jì)與選擇····································································46
7.4 固定板的設(shè)計(jì)與選擇·································································49
7.5 導(dǎo)料銷的設(shè)計(jì)與選擇·································································50
7.6 卸料螺釘?shù)倪x擇·······································································50
7.7 定位零件的設(shè)計(jì)與選擇·······························································51
7.7.1 擋料銷的選用·······································································51
7.7.2 銷釘?shù)倪x取·········································································51
7.8 推桿的設(shè)計(jì)與選擇····································································53
7.9 打料板的設(shè)計(jì)與選擇··································································53
7.10 頂桿的設(shè)計(jì)與選擇···································································53
參考文獻(xiàn)·····················································································56
畢業(yè)實(shí)習(xí)報(bào)告···············································································57
附錄或后記··················································································62
附:英文翻譯···············································································63
英文原文···············································································69
河北建筑工程學(xué)院
畢業(yè)設(shè)計(jì)計(jì)算書
指導(dǎo)教師:孫長(zhǎng)山
設(shè)計(jì)題目:前板連續(xù)模設(shè)計(jì)及沖壓工藝分析 設(shè)計(jì)人:劉松
設(shè)計(jì)項(xiàng)目
計(jì)算與說(shuō)明
結(jié)果
第1章 前言
1.1沖壓的概念、特點(diǎn)及應(yīng)用
沖壓是利用安裝在沖壓設(shè)備(主要是壓力機(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(俗稱沖壓或沖壓件)的一種壓力加工方法。沖壓通常是在常溫下對(duì)材料進(jìn)行冷變形加工,且主要采用板料來(lái)加工成所需零件,所以也叫冷沖壓或板料沖壓。沖壓是材料壓力加工或塑性加工的主要方法之一,隸屬于材料成型工程術(shù)。
沖壓所使用的模具稱為沖壓模具,簡(jiǎn)稱沖模。沖模是將材料(金屬或非金屬)批量加工成所需沖件的專用工具。沖模在沖壓中至關(guān)重要,沒有符合要求的沖模,批量沖壓生產(chǎn)就難以進(jìn)行;沒有先進(jìn)的沖模,先進(jìn)的沖壓工藝就無(wú)法實(shí)現(xiàn)。沖壓工藝與模具、沖壓設(shè)備和沖壓材料構(gòu)成沖壓加工的三要素,只有它們相互結(jié)合才能得出沖壓件。
與機(jī)械加工及塑性加工的其它方法相比,沖壓加工無(wú)論在技術(shù)方面還是經(jīng)濟(jì)方面都具有許多獨(dú)特的優(yōu)點(diǎn)。主要表現(xiàn)如下:
(1)沖壓加工的生產(chǎn)效率高,且操作方便,易于實(shí)現(xiàn)機(jī)械化與自動(dòng)化;
(2)沖壓時(shí)由于模具保證了沖壓件的尺寸與形狀精度,且一般不破壞沖壓件的表面質(zhì)量,而模具的壽命一般較長(zhǎng),所以沖壓的質(zhì)量穩(wěn)定,互換性好等特征;
(3)沖壓可加工出尺寸范圍較大、形狀較復(fù)雜的零件,如小到鐘表的秒表,大到汽車縱梁、覆蓋件等,加上沖壓時(shí)材料的冷變形硬化效應(yīng),沖壓的強(qiáng)度和剛度均較高;
設(shè)計(jì)項(xiàng)目
計(jì)算與說(shuō)明
結(jié)果
(4)沖壓一般沒有切屑碎料生成,材料的消耗較少,且不需其它加熱設(shè)備,因而是一種省料,節(jié)能的加工方法,沖壓件的成本較低;
1.2 沖壓的基本工序及模具
由于沖壓加工的零件種類繁多,各類零件的形狀、尺寸和精度要求又各不相同,因而生產(chǎn)中采用的沖壓工藝方法也是多種多樣的。概括起來(lái),可分為分離工序和成形工序兩大類;分離工序是指使坯料沿一定的輪廓線分離而獲得一定形狀、尺寸和斷面質(zhì)量的沖壓(俗稱沖裁件)的工序;成形工序是指使坯料在不破裂的條件下產(chǎn)生塑性變形而獲得一定形狀和尺寸的沖壓件的工序。按基本變形方式不同又可分為沖裁、彎曲、拉深和成形四種基本工序,每種基本工序還包含有多種單一工序。
在實(shí)際生產(chǎn)中,當(dāng)沖壓件的生產(chǎn)批量較大、尺寸較少而公差要求較小時(shí),若用分散的單一工序來(lái)沖壓是不經(jīng)濟(jì)甚至難于達(dá)到要求。這時(shí)在工藝上多采用集中的方案,即把兩種或兩種以上的單一工序集中在一副模具內(nèi)完成,稱為組合的方法不同,又可將其分為復(fù)合、級(jí)進(jìn)和復(fù)合-級(jí)進(jìn)三種組合方式。
復(fù)合沖壓——在壓力機(jī)的一次工作行程中,在模具的同一工位上同時(shí)完成兩種或兩種以上不同單一工序的一種組合方法式。
級(jí)進(jìn)沖壓——在壓力機(jī)上的一次工作行程中,按照一定的順序在同一模具的不同工位上完面兩種或兩種以上不同單一工序的一種組合方式。復(fù)合-級(jí)進(jìn)——在一副沖模上包含復(fù)合和級(jí)進(jìn)兩種方式的組合工序。
沖模的結(jié)構(gòu)類型也很多。通常按工序性質(zhì)可分為沖裁模、彎曲模、拉深模和成形模等;按工序的組合方式可分為單工序模、復(fù)合模和級(jí)進(jìn)模等。
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但不論何種類型的沖模,都可看成是由上模和下模兩部分組成,上模被固定在壓力機(jī)工作臺(tái)或墊板上,是沖模的固定部分。
1.3 連續(xù)模介紹
連續(xù)模是在單工序沖壓模的基礎(chǔ)上發(fā)展起來(lái)的一種多工序、高效率沖模,在一幅模具中有規(guī)律地安排多個(gè)工序進(jìn)行連續(xù)沖壓。連續(xù)模沖裁可以減少模具和設(shè)備數(shù)量,生產(chǎn)率高,操作方便安全,便于實(shí)現(xiàn)沖壓生產(chǎn)自動(dòng)化,在大批量生產(chǎn)中效果顯著。但各個(gè)工序是在不同的工步位置上完成的,由于定位誤差影響工件精度,一般多用于精度要求較低、多工序小零件。
連續(xù)模的工步安排是很靈活的,但不論其排樣如何,必須遵循一條規(guī)律:為了保證送料的連續(xù)性,工件與條料的完全分離(落料或切斷)要安排在最后的工步位置。每一工位可以安排一種或多種工序,也可以特意安排一個(gè)或多個(gè)空位,以增加和凹模的壁厚,加大凹模的外形尺寸,提高凹模強(qiáng)度,或避免模具零件過(guò)于緊湊,造成加工和安裝的困難。
1.4 連續(xù)模結(jié)構(gòu)分析
連續(xù)模沖壓主要由以下幾部分組成:
(1)工作零件——是實(shí)現(xiàn)沖裁變形使材料正確分離的零件,包括凸模、凹模。沖裁凸模與凹模有兩個(gè)突出特征:工作刃口鋒利和它們之間有合理的間隙。凸模與凹模刃口的利鈍和間隙的大小及其分布的均勻性直接影響沖裁件質(zhì)量,且影響沖裁力、卸料力和模具壽命。
(2)定位零件——確定條料在沖模中的正確位置的零件。導(dǎo)料銷對(duì)條料送進(jìn)起導(dǎo)向作用,擋料銷限制條料送進(jìn)的位置。擋料銷至凹??走叺木嚯x視排樣而定。
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(3)卸料及推件零件——是將由于沖裁后彈性回復(fù)而卡在凹模孔內(nèi)和凸模上的工件或廢料脫卸下來(lái)的零件。卡在凹模內(nèi)的工件,利用凹模沖裁時(shí)一個(gè)接一個(gè)地由凹??淄坡洹U條料退出凹模,則由卸料板、橡皮及卸料螺釘組成的卸料裝置,利用壓縮橡皮產(chǎn)生的卸料力來(lái)完成。
(4)導(dǎo)向零件——是保證上模對(duì)下模正確運(yùn)動(dòng)的零件。分別壓裝在上、下模座的導(dǎo)套和導(dǎo)柱,組成上、下模的導(dǎo)向裝置。采用導(dǎo)向裝置以保證沖裁時(shí),凸模和凹模之間的間隙均勻,有利于提高沖裁件質(zhì)量和模具壽命。
(5)連接固定零件——是將凸、凹模固定于上、下模座,以及將上、下模固定在壓力機(jī)上的零件。凸模通過(guò)固定板與上模座固定,凹模直接與下模座固定。
1.5 連續(xù)模設(shè)計(jì)要點(diǎn)
(1)要合理地進(jìn)行工序安排:
①在沖孔與落料工序次序安排時(shí),應(yīng)先安排沖孔,后安排落料,以便于使先沖好的孔,作為導(dǎo)正定位孔,以提高制件精度;
②在沒有圓形孔的制品中,為了提高送料步距精度,除了用定距側(cè)刃定距外,應(yīng)在凹模首次步序中,預(yù)先沖一圓孔,作為導(dǎo)正工藝孔并設(shè)計(jì)有導(dǎo)正釘,通過(guò)此孔定位,提高制品及送料精度;
③在產(chǎn)品要求孔與外形的某突出部位位置精度時(shí),應(yīng)把此部位與此孔設(shè)計(jì)在同一步位形成同一尺寸基準(zhǔn)的精度要求較高的不同孔,在不影響凹模強(qiáng)度情況下,應(yīng)安排在同一工步進(jìn)行沖裁;
④尺寸精度要求較高的工步,盡量安排在最后一道工序進(jìn)行沖裁。尺寸精度要求不太高的工步,則應(yīng)安排在較前工序;
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⑤沖不同形狀及尺寸的多孔工序時(shí),盡量不要把大孔及小孔同時(shí)安排在同一工序,以便修模時(shí)能確保孔距精度。
(2)要正確繪制排樣圖:
①繪制排樣圖時(shí),可以先從平面展開圖開始,向右設(shè)計(jì)沖裁工位,向左設(shè)計(jì)成型工位,然后根據(jù)實(shí)際情況逐步修正;
②要確定合適的切口方式;
③要注意金屬的纖維方向及毛刺方向,其毛刺應(yīng)位于彎曲件的內(nèi)側(cè);
④對(duì)于薄板連續(xù)模沖壓,可以用導(dǎo)正銷定位,不必切邊,但對(duì)于厚板料則需要側(cè)刃定位定距,需要切邊,在排樣圖中要畫出;
⑤要盡量提高材料的合理利用,做到經(jīng)濟(jì)排樣,或利用切下廢料,沖制其他工件。
(3)要合理地確定工位數(shù)及空位工位:
①工位的確定原則;
A確定工位數(shù)時(shí),根據(jù)排樣圖及工序安排應(yīng)保證工件的幾何形狀的正確。對(duì)于精度要求較高的部位,應(yīng)盡量集中在一個(gè)工位一次沖壓完成,以避免步距誤差影響精度要求;
B對(duì)于復(fù)雜的形孔與外形分段切除時(shí),應(yīng)力求做到各段形孔的形狀要簡(jiǎn)單、規(guī)則和容易加工;
C確定工位時(shí),工位數(shù)要盡量少,能合并的工位盡量不要分開,以減少步距的積累誤差;
D多次拉伸的連續(xù)模,為保證安全、穩(wěn)定其拉深次數(shù)若經(jīng)計(jì)算在3、4次之間,應(yīng)取4次拉深,以保證連續(xù)沖壓的合格率。
②空位的設(shè)置原則。
為增加凹模強(qiáng)度,便于凸模安裝固定,再模具設(shè)計(jì)中,往往要安排不進(jìn)行沖壓的空工位,其安置原則是:
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A用導(dǎo)正銷作為精確定位的條料,因步距誤差小,可適當(dāng)多設(shè)空位工位;
B當(dāng)模具步距較大時(shí),不宜多設(shè)空工位;
C精度高、形狀復(fù)雜的工件應(yīng)少設(shè)空工位;
D凸模離的較近時(shí),可設(shè)空工位。
(4)要設(shè)計(jì)完好的導(dǎo)料及浮頂裝置
在設(shè)計(jì)連續(xù)模時(shí),必須設(shè)計(jì)完好的導(dǎo)料系統(tǒng),以保證條料在模具中能正常的運(yùn)行。
在連續(xù)模中一般是條料或卷料送進(jìn),對(duì)其材質(zhì)、厚度、寬度等均有嚴(yán)格的要求。連續(xù)模的導(dǎo)料系統(tǒng)一般是由兩條導(dǎo)料板及延伸凹模之外的承料板構(gòu)成,為了防止條料送進(jìn)過(guò)程中發(fā)生擺動(dòng),應(yīng)設(shè)計(jì)有側(cè)壓裝置,對(duì)于多工位復(fù)合連續(xù)模,必須要設(shè)計(jì)有浮頂器,以使條料浮離在下模平面,保證沖壓連續(xù)正常進(jìn)行。
(5)要設(shè)計(jì)出可靠的卸料機(jī)構(gòu)
連續(xù)模在每次沖壓過(guò)程完成后,應(yīng)立即將條料從凸模中卸下,浮頂器將條料浮離在下模平面,廢余料及時(shí)排除。連續(xù)模常用的卸料機(jī)構(gòu)分固定式及彈壓式兩種,在多工位連續(xù)模中,多采用彈壓式卸料機(jī)構(gòu)它不僅起卸料作用,還有壓料及導(dǎo)正凸模的功能。如在沖裁連續(xù)模及沖裁工序中,它起卸料和壓料作用,而在彎曲工序中能起局部成形作用,而在拉深工序中又起壓邊圈作用。因此在設(shè)計(jì)連續(xù)模時(shí),要設(shè)計(jì)出可靠的卸料機(jī)構(gòu)以保證沖壓正常進(jìn)行。在多工位連續(xù)模中,卸料板多采用鑲拼結(jié)構(gòu),這樣才能保證孔精度、配合間隙和孔表面粗糙度等要求。
(6)要設(shè)計(jì)出精確的定距機(jī)構(gòu)
在連續(xù)模中,條料送進(jìn)時(shí)定位要準(zhǔn)確,才有可能加工出合格的沖件。常用的定距方法,主要是:
①側(cè)刃定位法:側(cè)刃定位是利用側(cè)刃及側(cè)刃當(dāng)塊作
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為條料的定位及定距,其定距精度較高,操作比較方便,常用于板料厚度在0.1~0.5mm厚連續(xù)模沖裁中,但由于側(cè)刃的尺寸很難與模具實(shí)際進(jìn)距尺寸相一致,所以一般只在精度要求不高的沖裁連續(xù)模使用;
②導(dǎo)正銷定位法:導(dǎo)正銷定位是連續(xù)模中普遍采用的定位方式,它一般與側(cè)刃一起聯(lián)合使用,即側(cè)刃作粗定位,導(dǎo)正銷做精定位可以達(dá)到很高的定位、定距精度。設(shè)計(jì)模具時(shí),導(dǎo)正銷與卸料板應(yīng)加工成H7/h6或H6/h5配合形式,與固定板加工成 H7/h6配合。
(7)凸凹模結(jié)構(gòu)設(shè)計(jì)要合理
在設(shè)計(jì)連續(xù)模時(shí),凸模與凹模孔的數(shù)量較多,故在設(shè)計(jì)凸、凹模時(shí),除了能保證正常的沖壓要求外,還應(yīng)注意以下幾點(diǎn):
①凸模的結(jié)構(gòu)設(shè)計(jì)要充分考慮其安裝的穩(wěn)定性及壽命長(zhǎng)短,尤其是對(duì)于高速連續(xù)沖壓的凸模設(shè)計(jì)更應(yīng)注意;
②凸模的高度一般為35~65mm,盡量選用標(biāo)準(zhǔn)高度,如35、40、45mm。其高度應(yīng)留有足夠的刃磨余量,并使各個(gè)凸模具有相一致的刃磨余量大小;
③對(duì)于形狀復(fù)雜的凹模,最好采用鑲拼結(jié)構(gòu)。
(8)要有可靠的安全監(jiān)測(cè)機(jī)構(gòu)
對(duì)于多工序復(fù)合連續(xù)模,設(shè)計(jì)時(shí)要注意:
①模具要設(shè)計(jì)出防護(hù)罩,以確保沖壓時(shí)的安全;
②對(duì)于自動(dòng)化程度很高的連續(xù)模,應(yīng)設(shè)計(jì)有在條料上的清除廢物及潤(rùn)滑裝置;
③為了監(jiān)測(cè)模具在沖壓過(guò)程中所產(chǎn)生的不安全狀況,在自動(dòng)送退料連續(xù)模中,應(yīng)設(shè)計(jì)有監(jiān)控檢測(cè)機(jī)構(gòu),如果沖壓過(guò)程中一旦發(fā)現(xiàn)故障,則由檢測(cè)機(jī)構(gòu)獲取的信號(hào)立即傳遞給控制系統(tǒng),使壓力機(jī)停止運(yùn)動(dòng)從而避免事故的發(fā)生。
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第2章 連續(xù)模設(shè)計(jì)過(guò)程
2.1 沖件工藝性分析
2.1.1沖裁件結(jié)構(gòu)工藝性
工件為圖2-1所示的落料件,材料為普通碳素鋼材料厚度為0.13mm生產(chǎn)批量為大批量。該沖壓成品零件工藝性分析內(nèi)容如下:
(1)普通碳素鋼具有良好的沖壓成型性能,塑性好、變形抗力低、組織結(jié)構(gòu)好
(2)該沖裁件的形狀符合材料合理排樣,有利于減少?gòu)U料、節(jié)約材料。
(3)該沖裁件各直線或曲線的連線處,有適當(dāng)?shù)膱A角對(duì)于模具的制造和使用壽命有利。
(4)該沖裁件凸出或凹入部分寬度適宜,但是外輪廓結(jié)構(gòu)復(fù)雜加工比較困難。
圖 2-1 前板工件圖
2.1.2 沖裁件的精度和毛刺
沖裁件的精度一般可分為精密級(jí)與經(jīng)濟(jì)級(jí)兩類,精密級(jí)是沖壓工藝技術(shù)上所允許的精度,而經(jīng)濟(jì)級(jí)是可以
用較經(jīng)濟(jì)手段達(dá)到的精度。該構(gòu)件表面潔凈,毛刺高度
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不大于0.02mm。根據(jù)機(jī)械工業(yè)出版社出版的《沖模設(shè)計(jì)手冊(cè)》 P28頁(yè) 表2-3可知該沖裁件的精度等級(jí)是經(jīng)濟(jì)級(jí)。
2.2 工藝方案的設(shè)定
該零件有以下基本工序:落料、沖Φ1.0mm圓孔、、沖導(dǎo)正銷孔、四處彎曲、成形等。根據(jù)沖壓件的尺寸及加工方式分析可得出以下倆種加工方案:
工藝方案一:復(fù)合模沖壓加工
復(fù)合模能在壓力機(jī)一次行程內(nèi),完成落料、沖孔及拉深等數(shù)道工序。在完成這些工序過(guò)程中,沖件材料無(wú)需進(jìn)給移動(dòng)。
復(fù)合模具有以下特點(diǎn):
(1)沖件精度較高,不受送料誤差影響,內(nèi)外形相對(duì)位置各件一致;
(2)沖件表面較為平直;
(3)適宜沖薄料,也適宜沖脆性或軟質(zhì)材料;
(4)可以充分利用短料和邊角余料;
(5)沖模面積較小。
工藝方案二:連續(xù)模沖壓加工
連續(xù)模具有以下特點(diǎn):
(1)連續(xù)模是多工序沖模。在一副模具內(nèi),可以包括沖裁、彎曲、和拉深等多種多道工序,具有比復(fù)合模更高的勞動(dòng)生產(chǎn)率;
(2)連續(xù)模具有操作安全這樣一個(gè)顯著特點(diǎn),因?yàn)槭窒虏槐剡M(jìn)入危險(xiǎn)區(qū)域;
(3)因?yàn)楣ば蚩梢苑稚?,不必集中在一個(gè)工位,不存在復(fù)合模 “最小壁厚”的問(wèn)題,因此模具強(qiáng)度較高,壽命較長(zhǎng);
(4)連續(xù)模易于自動(dòng)化,包括自動(dòng)送料,自動(dòng)出件,自動(dòng)疊鉚;
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結(jié)果
(5)連續(xù)模工件和廢料均往下漏,因而可以采用高速壓力機(jī)生產(chǎn);
(6)使用連續(xù)??梢詼p少壓力機(jī)、車間面積,半制品運(yùn)輸及倉(cāng)庫(kù)面積。
根據(jù)沖件的工藝分析,并比較以上兩種工藝方案特點(diǎn),該沖壓件的厚度不滿足復(fù)合模最小壁厚的要求。綜合考慮本設(shè)計(jì)采用連續(xù)模沖壓加工更有利于多道工序的加工、實(shí)現(xiàn)自動(dòng)化生產(chǎn),從而提高生差率提高成品工件的加工質(zhì)量。
2.3 間隙的含義及間隙值的選擇
2.3.1 沖載間隙分析
(1)間隙對(duì)沖載件尺寸精度的影響:
沖載件的尺寸精度是指沖載件的實(shí)際尺寸與基本尺寸的差值,差值越小,則精度越高,這個(gè)差值包括兩個(gè)方面的偏差,一是沖載件相對(duì)于凸?;虬寄5钠?,二是模具本身的制造偏差。
(2)間隙對(duì)模具壽命的影響;
模具壽命受各種因素的綜合影響,間隙也許是模具壽命諸因素中最主要的因素之一,沖載過(guò)程中,凸模與被沖的孔之間,凹模與落料件之間均有摩擦,而且間隙越小,模具作用的壓應(yīng)力越大,摩擦也越嚴(yán)重,所以過(guò)小的間隙對(duì)模具壽命極為不利,而較大的間隙可使凸模側(cè)面及材料間的摩擦減小,并延緩間隙由于受到制造和裝配精度的限制,出現(xiàn)間隙不均勻的不利影響,從而提高模具壽命。
(3)間隙對(duì)沖載工藝力的影響
隨著間隙的增大,材料所受到的拉應(yīng)力增大,材料容易斷裂分離,因此沖載力減小。通常沖載力的降低并不顯著,當(dāng)單邊間隙在材料厚度的左右時(shí),沖載
設(shè)計(jì)項(xiàng)目
計(jì)算與說(shuō)明
結(jié)果
力的降低不超過(guò)。間隙對(duì)卸料力和推料力的影響比較顯著。間隙增大后,從凸模里卸料和從凹模里推料都省力,當(dāng)單邊間隙達(dá)到材料厚度的左右時(shí)的卸料力幾乎為零,但間隙繼續(xù)增大,因?yàn)槊淘龃?,又將引起卸料力、頂件力迅速增大?
(4)間隙值的確定
由以上分析可見,凸、凹模間隙對(duì)沖載件質(zhì)量、沖載工藝、模具壽命都有很大的影響。因此,設(shè)計(jì)模具時(shí)
一定要選擇合理的間隙,以保證沖載件的斷面質(zhì)量、尺寸精度滿足產(chǎn)品的要求,所需沖載力小、模具壽命高,但分別從質(zhì)量,沖載力、模具壽命等方面的要求確定的合理間隙并不是同一個(gè)數(shù)值,只是彼此接近??紤]到模具制造中的偏差及使用中的磨損、生產(chǎn)中通常只選擇一
個(gè)合適的范圍作為合理間隙,只要間隙在這個(gè)范圍內(nèi),就可以沖出良好的制件,這個(gè)范圍的最小值稱為最小合理間隙,最大值稱為最大。考慮到模具在使用過(guò)程中的磨損使間隙增大,故設(shè)計(jì)與制造新模具時(shí)要采用最小合理間隙值。
2.3.2 間隙值的選擇
模具間隙是指凸、凹模刃口間縫隙的距離,若用符號(hào)Z表示,俗稱單面間隙。而雙面間隙用2Z表示。間隙對(duì)沖裁件質(zhì)量、沖裁力、模具壽命的影響很大,是沖裁工藝與模具設(shè)計(jì)中的一個(gè)極其重要的問(wèn)題。間隙對(duì)沖裁件的斷面質(zhì)量、尺寸精度、及沖裁力都有很大的影響,合理間隙的選擇:
t=0.13 Zmin=0.010 Z=+0.010
2.4 沖壓加工工序及排樣圖設(shè)計(jì)
沖壓材料使用鋼帶卷料,材料厚0.13mm。采用自動(dòng)的展料邊緣;送料器送料。
設(shè)計(jì)項(xiàng)目
計(jì)算與說(shuō)明
結(jié)果
圖2-2 沖壓排樣圖
工件的沖裁排樣圖如圖2-2所示。共有八個(gè)工位。
第1工位:沖導(dǎo)正銷孔;
第2工位:沖工件右側(cè)兩個(gè)1孔;
第3工序:沖工件左側(cè)1孔,然后沖右下方、右上方的展料邊緣;
第4工序:空工位;
第5工序:沖工件左下方、左上方的展料邊緣;
第6工序:沖工件左右兩側(cè)的展料邊緣;
第7工序:吹料;
第8工序:將展料從條料上分離,并將其彎曲。
2.5 凸模、凹模尺寸的計(jì)算
沖裁工件的平面展開圖如圖2-3所示:
2.5.1 外形尺寸的計(jì)算
外形尺寸分為五類:
1.A類,刃口后凹模尺寸兩邊增大的,計(jì)算這類尺寸先把產(chǎn)品零件圖尺寸化成形式
2.a類,刃口后凹模尺寸一邊增大的,計(jì)算這類尺寸要先把產(chǎn)品零件圖尺寸化成形式。
3.B類,刃口后凹模尺寸兩邊減小的,計(jì)算這類尺寸,要求先把產(chǎn)品零件圖尺寸化形式。
4.b類,刃口后凹模尺寸一邊減小的,計(jì)算這類尺寸,要求先把產(chǎn)品零件圖尺寸化成形式。
5.C類,刃口后凹模尺寸不變的,計(jì)算這類尺寸,要求把零件圖尺寸化成L±/2形式。
設(shè)計(jì)項(xiàng)目
計(jì)算與說(shuō)明
結(jié)果
圖2-3 前板工件展開圖
2.5.2 內(nèi)形尺寸的計(jì)算
內(nèi)形尺寸也分五類:
1.E類,刃口后凹模尺寸兩邊增大的,計(jì)算這類尺寸要先把零件圖尺寸化成形式 。
2.e類,刃口后凹模尺寸一邊增大的,計(jì)算這類尺寸要先把產(chǎn)品零件圖尺寸化成形式。
3.F類,刃口后凹模尺寸兩邊減小的, 計(jì)算這類尺寸, 要求先把產(chǎn)品零件圖尺寸化成形式。
4.f類,刃口后凹模尺寸一邊減小的,計(jì)算這類尺寸,要求先把產(chǎn)品零件圖尺寸化成形式。
5.G類,刃口后凹模尺寸不變的,計(jì)算這類尺寸,要求把零件圖尺寸化成G±/2形式。
根據(jù)以上分類標(biāo)注沖壓件件圖如圖2-4。
設(shè)計(jì)項(xiàng)目
計(jì)算與說(shuō)明
結(jié)果
圖 2-4標(biāo)注件圖
設(shè)計(jì)項(xiàng)目
計(jì)算與說(shuō)明
結(jié)果
1 落料件基本尺寸計(jì)算公式
2 凸模落料件部分的尺寸計(jì)算
第3章 落料件凸凹模尺寸計(jì)算過(guò)程
凹凸模部分的尺寸計(jì)算均參照參考文獻(xiàn)【3】《簡(jiǎn)明沖模設(shè)計(jì)手冊(cè)》中的公式與計(jì)算方法。
3.1刃口尺寸計(jì)算
根據(jù)零件的形狀特點(diǎn),分析可得刃口尺寸計(jì)算采用分開制造法。
1 落料件基本尺寸計(jì)算公式:由參考文獻(xiàn)【3】中的P33頁(yè) 表4-6 凸模、凹模刃口計(jì)算公式可得:
(1)凸模尺寸計(jì)算公式:
(2)凹模尺寸計(jì)算公式:
式中,---落料件凹、凸模公稱尺寸(mm);
--- 落料件基本尺寸,(mm);
--- 落料件公差,(mm);
---凹、凸模的最小單面間隙,(mm);
、---凹、凸模的制造公差,(mm)
其中=/4
x---磨損系數(shù),根據(jù)摩擦情況和工件的公差,通常可取 x=0.5-1,本設(shè)計(jì)計(jì)算書中x=0.75。
2 凸模落料件部分的尺寸計(jì)算:
設(shè)計(jì)項(xiàng)目
計(jì)算與說(shuō)明
結(jié)果
設(shè)計(jì)項(xiàng)目
計(jì)算與說(shuō)明
結(jié)果
設(shè)計(jì)項(xiàng)目
計(jì)算與說(shuō)明
結(jié)果
設(shè)計(jì)項(xiàng)目
計(jì)算與說(shuō)明
結(jié)果
3 凹模尺寸計(jì)算
1孔部分凸凹模尺寸計(jì)算公式
2 沖孔件凹模部分的尺寸計(jì)算
3 凹模尺寸采用公式:
3.2 沖孔部分凸凹模尺寸計(jì)算
1孔部分凸凹模尺寸計(jì)算公式:由參考文獻(xiàn)【3】中的P33頁(yè) 表4-6 凸模、凹模沖孔計(jì)算公式可得:
(1)凸模尺寸計(jì)算公式:
(2) 凹模尺寸計(jì)算公式:
式中 ,---沖孔件凹、凸模公稱尺寸(mm);
--- 沖孔件基本尺寸,(mm);
--- 沖孔件公差,(mm);
---凹、凸模的最小單面間隙,(mm);
、---凹、凸模的制造公差,(mm)
其中=/4
x---磨損系數(shù),根據(jù)摩擦情況和工件的公差,通??扇?x=0.5-1,本設(shè)計(jì)計(jì)算書中x=0.75。
2 沖孔件凹模部分的尺寸計(jì)算:
(1)
(2)
(3)
x=0.75
設(shè)計(jì)項(xiàng)目
計(jì)算與說(shuō)明
結(jié)果
3 沖孔件凸模部分尺寸計(jì)算
沖裁力的計(jì)算
(4)
3 沖孔件凸模部分尺寸計(jì)算采用公式:
第4章 沖壓力的計(jì)算
4.1 沖裁件的力學(xué)性能分析
材料名稱: 普通碳素鋼;
材料牌號(hào): Q255;
材料狀態(tài): 未經(jīng)退火的;
抗剪強(qiáng)度τ/MPa: 340~420;
抗拉強(qiáng)度σb/MPa: 490~520;
伸長(zhǎng)率δ(%): 19~23;
屈服點(diǎn)σs/MPa: 260;
彈性模量E/MPa: -
4.2 沖裁件沖裁力的計(jì)算
沖裁力的計(jì)算公式查參考文獻(xiàn)【3】P38 4.5.1可得一般平刃口模具沖裁時(shí)其沖裁力可按下式計(jì)算,即
式中 ---沖裁力 (N);
t---材料厚度( mm);
A---剪切斷面面積;
τ---材料抗剪強(qiáng)度(MPa);
L---材料沖裁的輪廓長(zhǎng)度(mm)。
把以上的數(shù)據(jù)帶入計(jì)算可得:
設(shè)計(jì)項(xiàng)目
計(jì)算與說(shuō)明
結(jié)果
卸料力計(jì)算
4.3 沖裁件卸料力的計(jì)算
沖裁結(jié)束后,將工件或廢料從凸模上卸下來(lái)的力為卸料力。
沖裁力的計(jì)算公式查參考文獻(xiàn)【3】P40 4.5.3 可得一般平刃口模具沖裁時(shí)其沖裁力可按下式計(jì)算,即:
式中 ---卸料力(N);
---卸料力系數(shù);
P---沖裁力;
---沖裁件平刃口沖裁力(N)。
(1)卸載力系數(shù)可由參考文獻(xiàn)【3】P41 表4-15查取得:,
(2)沖裁力可由4.2沖裁件沖裁力的計(jì)算得:
將以上數(shù)據(jù)代入卸料力的計(jì)算公式可得:
4.4 沖裁件推件力的計(jì)算
沖裁結(jié)束后,將工件或廢料從凹模內(nèi)順沖裁方向推出來(lái)的力為推件力。
推件力的計(jì)算公式查參考文獻(xiàn)【3】P40 4.5.3 可得一般平刃口模具沖裁時(shí)其推件力可按下式計(jì)算,
即
式中 F0---沖裁件平刃口沖裁力(N);
n---同時(shí)卡在凹模內(nèi)的工件或廢料數(shù);
---推件力系數(shù);
t---料厚(mm);
h---凹模洞口直臂高度(mm)。
設(shè)計(jì)項(xiàng)目
計(jì)算與說(shuō)明
結(jié)果
推件力計(jì)算
頂件力計(jì)算
(1)推件力系數(shù)可由參考文獻(xiàn)【3】P41表4-15 查取得:,
(2)沖裁力可由4.2沖裁件沖裁力的計(jì)算得:
4.5 沖裁件頂件力的計(jì)算
沖裁結(jié)束后,逆沖方向?qū)⒐ぜ驈U料從凹模洞口頂出的力為頂件力。
頂件力的計(jì)算公式查參考文獻(xiàn)【3】P40 4.5.3 可得一般平刃口模具沖裁時(shí)其頂件力可按下式計(jì)算:
即
式中 F0---沖裁件平刃口沖裁力(N);
---推件力系數(shù)。
(1)頂件力系數(shù)可由參考文獻(xiàn)【3】P41表4-15 查取得:,
(2)沖裁力可由4.2沖裁件沖裁力的計(jì)算得:
將以上數(shù)據(jù)代入頂件力的計(jì)算公式可得:
4.6 沖裁件彎曲力的計(jì)算
四個(gè)部位的彎曲均屬于自由彎曲,彎曲力的計(jì)算公式查參考文獻(xiàn)【3】 P95 表6-10 可得:
式中:F---總彎曲力(N);
B---彎曲件寬度(mm);
t---料厚(mm);
設(shè)計(jì)項(xiàng)目
計(jì)算與說(shuō)明
結(jié)果
彎曲力計(jì)算
---抗拉強(qiáng)度(MPa);
r---內(nèi)彎曲半徑(mm);
式中圓角半徑r=0.1mm,沖裁件的板厚t=0.13mm,屈服極限σb=350MPa,式中板料寬度B=29.2mm。由上式可以計(jì)算出四個(gè)部分的總彎曲力為835.84N。
4.7 沖裁件壓力中心的計(jì)算
沖裁件的壓力中心的計(jì)算公式可查參考文獻(xiàn)【1】中的 P16 2.1.3 中的4、壓力中心計(jì)算可得壓力中心計(jì)算的通用式:
式中:(1)、、… 分別為沖裁工件所分成的n條直線的長(zhǎng)度