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畢 業(yè) 設(shè) 計(jì)(論 文)
設(shè)計(jì)(論文)題目:踏板組件(B)沖壓模具設(shè)計(jì)
學(xué)生姓名: 葉丞
學(xué) 院: 機(jī)械與電氣工程學(xué)院
專 業(yè): 材料成型及控制工程
班 級(jí): 116152B
學(xué) 號(hào): 12016152038
指導(dǎo)教師: 魏楓
2020年4月25日
摘 要
此設(shè)計(jì)說明書的內(nèi)容里,包含有兩個(gè)方面的內(nèi)容,其一是有關(guān)模具的主要發(fā)展形勢,其二是我對(duì)于踏板組件的沖壓模具設(shè)計(jì)介紹。我主要負(fù)責(zé)設(shè)計(jì)的是該U型件的沖孔、落料工序,用復(fù)合模完成該部分工序的生產(chǎn)。首先考慮了產(chǎn)品的質(zhì)量要求和生產(chǎn)的實(shí)際情況,確定了最佳工藝方案,同時(shí)計(jì)算下料展開尺寸和零件壓力中心,計(jì)算模具中的凸凹模刃口尺寸,校核凸模強(qiáng)度以及壓力機(jī)的核查,精確詳細(xì)地對(duì)有關(guān)工藝參數(shù)進(jìn)行計(jì)算,準(zhǔn)確無誤的選擇壓力設(shè)備,同時(shí)對(duì)模具零件的結(jié)構(gòu)進(jìn)行設(shè)計(jì),適應(yīng)了目前沖壓模具的設(shè)計(jì)要求。然后進(jìn)行沖壓模具設(shè)計(jì),全部采用AutoCAD軟件進(jìn)行圖樣設(shè)計(jì),繪制出了二維裝配圖和零件圖,設(shè)計(jì)相關(guān)零部件結(jié)構(gòu),最后介紹了裝配工藝要求。
關(guān)鍵詞:模具制造;復(fù)合模;裝配;AutoCAD
Abstract
The content of this design specification includes two aspects, one is the main development situation of the mold, and the other is my introduction to the stamping mold design of the pedal assembly. I am mainly responsible for the design of the punching and blanking process of the U-shaped part, and use the compound die to complete the production of this part of the process. First of all, considering the quality requirements of the product and the actual situation of production, the optimal process plan is determined. At the same time, the blanking development size and the pressure center of the parts are calculated, the cutting edge size of the convex and concave die in the die is calculated, the punch strength and the verification of the press are checked, the relevant process parameters are calculated accurately and in detail, the pressure equipment is selected accurately, and the knot of the die parts is determined The structure is designed to meet the design requirements of the current stamping die. Then the stamping die design, all using AutoCAD software for drawing design, drawing out two-dimensional assembly drawings and parts drawings, design the structure of related parts, and finally introduce the assembly process requirements.
Keywords: mold manufacturing; compound mold; assembly; AutoCAD
目 錄
第一章 緒論 1
1.1模具市場發(fā)展趨勢 1
1.2模具設(shè)計(jì)技術(shù)的發(fā)展 1
第二章 零件的工藝性分析 1
2.1零件圖 1
2.2工藝性分析 2
第三章 確定沖壓件生產(chǎn)的總體工藝方案 2
3.1確定沖壓工序方案 2
3.2排樣設(shè)計(jì) 2
第四章 計(jì)算沖裁力及確定壓力中心 4
4.1計(jì)算沖裁力 4
4.1.1沖孔沖裁力的計(jì)算 4
4.1.2落料沖裁力的計(jì)算 4
4.1.3卸料力和推件力的計(jì)算 4
4.2沖壓設(shè)備的選擇 4
4.3確定壓力中心 5
第五章 模具總體結(jié)構(gòu)設(shè)計(jì) 6
5.1.凸、凹模間隙值的確定 6
5.2.凸、凹模刃口尺寸的確定 7
5.3主要零部件的設(shè)計(jì) 8
5.3.1沖孔凸模 8
5.3.2沖孔落料凸凹模 11
5.3.3落料凹模 12
5.3.4凸模固定板 13
5.3.5凸凹模固定板 14
5.3.6模架選用 14
5.3.7模柄 15
5.3.8卸料裝置 15
5.4模具總裝圖 16
第六章 壓力機(jī)的校核 17
6.1公稱壓力的校核 17
6.2裝模高度的校核 17
第七章 模具裝配要求 18
7.1保證設(shè)計(jì)參數(shù) 18
7.2正確裝配組件與零件 18
參考文獻(xiàn) 19
致謝 20
第一章 緒論
1.1模具市場發(fā)展趨勢
當(dāng)下中國機(jī)械工業(yè)飛速發(fā)展,模具在制造業(yè)中的地位越來越高,許多產(chǎn)業(yè)部門的發(fā)展都依賴于模具工業(yè)的發(fā)展。目前我國模具市場上低檔次模具居多,但是各行業(yè)對(duì)于模具的要求并沒有下降。為了追求產(chǎn)品更好的生產(chǎn)效率和使用性能,企業(yè)工廠更多的會(huì)采用高端模具來生產(chǎn),因此精密、復(fù)雜、長壽命的高檔模具市場前景廣闊。我們正站在我國制造業(yè)轉(zhuǎn)型的關(guān)鍵時(shí)期,減輕材料,降低能耗,開拓創(chuàng)新,是我們的目標(biāo)與追求,研發(fā)制造高檔模具、進(jìn)軍高端模具市場迫在眉睫。
此外,近些年來勞動(dòng)力成本在模具總成本中占比逐漸增加,發(fā)展中國家尤其是東南亞國家已經(jīng)成為模具生產(chǎn)的首選,但是經(jīng)過這幾十年的發(fā)展,我國勞動(dòng)力素質(zhì)和技術(shù)水平仍然有很大優(yōu)勢。同時(shí)現(xiàn)在國內(nèi)的模具性能各方面都增強(qiáng),并且制造的效率高,對(duì)于中高端模具出口,那將成為一新的大趨勢。
1.2模具設(shè)計(jì)技術(shù)的發(fā)展
沖壓加工是用途最為廣泛的傳統(tǒng)機(jī)械制造方法之一,在手工制造階段,采用鋸、鑿、錘等工具來制造模具;在機(jī)械化、半機(jī)械化階段,采用車床和刨床來制造模具;當(dāng)采用銑床和磨床來制模時(shí),這就是標(biāo)志著模具進(jìn)入初步工業(yè)化;最后,在19世紀(jì)30年代初模具進(jìn)入正式工業(yè)化。目前國外沖壓模具設(shè)計(jì)已廣泛使用CAD/CAE/CAM技術(shù)。目前來看,手繪圖板已經(jīng)不適合模具的現(xiàn)代化制造了,CAD技術(shù)在二維繪圖中已廣泛使用,目前3D設(shè)計(jì)已達(dá)到了70-89%。同時(shí)一些國家采用了先進(jìn)的設(shè)計(jì)理念,用一張加工要領(lǐng)圖將各沖壓工序的壓力中心、沖壓方向、加工部位、尺寸要求、加工內(nèi)容及相互關(guān)系等表示出來,不僅便于模具設(shè)計(jì),而且對(duì)模具加工和調(diào)整也方便。我國廣泛應(yīng)用和發(fā)展的復(fù)合模,在模具的技術(shù)含量、制造精度、使用壽命和制造周期等方面均獲得了明顯進(jìn)步。其中,部分高檔優(yōu)質(zhì)模具的總體水平與國際同類模具水平相當(dāng)。
第二章 零件的工藝性分析
2.1零件圖
沖壓件形狀尺寸如圖2-1所示
圖2-1 零件圖
2.2工藝性分析
選取零件材料鋁鎮(zhèn)靜鋼板(08AL),其抗剪強(qiáng)度σb=325 MPa,可塑性好、韌性也好,滿足該產(chǎn)品的性能及工作條件。同時(shí)該零件的形狀結(jié)構(gòu)簡單,沒有尺寸精度及表面粗糙度要求,便于模具設(shè)計(jì)加工和裝配,方便制定工藝規(guī)程。
第三章 確定沖壓件生產(chǎn)的總體工藝方案
3.1確定沖壓工序方案
這個(gè)踏板組件零件可以直接從零件圖上看出有沖孔、落料、彎曲、切舌等工序,本篇中我主要負(fù)責(zé)設(shè)計(jì)它的沖孔、落料兩道工序,選用單工位復(fù)合模,即沖孔落料復(fù)合沖壓。
3.2排樣設(shè)計(jì)
1.毛坯的尺寸計(jì)算
該制件彎曲端展開后的形狀尺寸:
最大長度L=2*L1+L2+2(πρα/180°)=2*23+52+π(2+0.14*2)=105.16mm
r=2,t=2,K取0.14
ρ=r+Kt
最大寬度B=40mm
毛坯展開圖如圖3-1所示
圖3-1 毛坯展開圖
工件平展后的面積F0=2871.69-103.62=2768.07mm2
2.確定零件的排樣方案
以短邊為進(jìn)給方向?qū)辶纤瓦M(jìn)壓力機(jī)沖壓
搭邊值a取3.0,b取3.0
排樣圖如圖3-2所示
圖3-2 排樣圖
板料寬度111.16mm,步距43mm
材料利用率η=F0/F×100%=2768.07/(111.16*43)=57.91%
第四章 計(jì)算沖裁力及確定壓力中心
4.1計(jì)算沖裁力
4.1.1沖孔沖裁力的計(jì)算
沖孔沖裁力根據(jù)文獻(xiàn)公式3-1,F(xiàn)=KLtσb進(jìn)行計(jì)算
式中 K——一般取K=1.3;
L——沖裁件周邊長度;
t——是代表材料的厚度,t=2mm;
σb——是代表材料的抗拉強(qiáng)度,查文獻(xiàn)得08AL的抗拉強(qiáng)度σb=325MPa
Φ10mm的凸模1沖裁力為F1=KLtσb=1.3*10π*2*325=26.533kN
Φ4 mm的凸模2沖裁力為F2=KLtσb=1.3*4π*2*325=10.613kN
Φ4 mm的凸模3沖裁力為F3=KLtσb=1.3*4π*2*325=10.613kN
特殊形狀凸模4沖裁力為F4=KLtσb=1.3*(2π+6+6+4)*2*325=18.827kN
所以,總沖裁力F沖=F1+F2+F3+F4=66.586kN
4.1.2落料沖裁力的計(jì)算
落料沖裁力根據(jù)文獻(xiàn)公式3-1,F(xiàn)=KLtσb進(jìn)行計(jì)算
式中 L=85.16+2*13.58+20π+24.11π=250.83mm
所以,沖裁力F落=1.3Ltσb=1.3*250.83*2*325=211951N=211.951kN
4.1.3卸料力和推件力的計(jì)算
1、卸料力是指在沖裁時(shí),從凸模上把工件或廢料取下來的力。查文獻(xiàn)公式3-3 F卸=K卸F沖進(jìn)行計(jì)算
查文獻(xiàn)表3-7 K卸取0.11,如圖4-1所示
所以,F(xiàn)卸=K卸F沖=0.11*66.586=7.32kN
2、把塞在凹模內(nèi)的料,順著沖裁方向推出,所需要的力被稱為推件力。推件力受到材料的力學(xué)性能、凸凹模表明粗糙度、零件形狀和尺寸等的影響。查文獻(xiàn)公式3-4 F推=nK推F落進(jìn)行計(jì)算
根據(jù)文獻(xiàn)表3-7 K推=0.07
所以,F(xiàn)推=nK推F落=1*0.07*211.951=14.84kN
圖4-1
4.2沖壓設(shè)備的選擇
①壓力機(jī)的公稱壓力必須大于或等于各種沖壓工藝力的總和FZ。FZ的計(jì)算應(yīng)根據(jù)不同的模具結(jié)構(gòu)分別計(jì)算取值。
采用彈性卸料裝置和下出料方式的沖裁模時(shí)
FZ1=F+FT=66.586+14.84=81.426kN
采用直接落料的沖裁模時(shí)
FZ2=F=211.951kN
F總=FZ1+FZ2=81.426+211.951=293.377kN
②查文獻(xiàn)表6-33,選擇開式可傾壓力機(jī),參數(shù)初選的壓力機(jī)型號(hào)為JG23-40,其公稱壓力為400kN,滑塊行程100mm,最大閉合高度300mm,封閉高度調(diào)節(jié)量80mm,滑塊中心線至床身距離190mm,工作臺(tái)尺寸700mm×460mm,模柄孔尺寸φ50mm×70mm。
4.3確定壓力中心
①以長底邊與對(duì)稱軸建立直角坐標(biāo)系,如圖4-2所示
圖4-2
②各個(gè)單元的重心為1,2,3,4,5,6,7,8;其各單元的坐標(biāo)位置為
X1=0,Y1=0;X2=0,Y2=10;X3=0,Y3=20;X4=0,Y4=30;X5=0,Y5=34.38;X6=-15,Y6=31.27;X7=-15,Y7=27;X8=-15,Y8=24
③計(jì)算出各單元沖裁的長度L1=85.16,L2=87.91,L3=27.16,L4=31.4,L5=75.71,L6=6.28,L7=12,L8=4
X0=(L1X1+L2X2+L3X3+L4X4+L5X5+L6X6+L7X7+L8X8)/(L1+L2+L3+L4+L5+L6+L7+L8)=(0+0+0+0+0-6.28*15-12*15-4*15)/(85.16+87.91+27.16+31.4+75.71+6.28+12+4)=-78.28/329.62=-0.24
Y0=(L1Y1+L2Y2+L3Y3+L4Y4+L5Y5+L6Y6+L7Y7+L8Y8)/(L1+L2+L3+L4+L5+L6+L7+L8)=(0+879.1+543.2+942+2602.91+196.38+324+96)/329.62=5583.59/329.62=16.94
壓力中心為(-0.24,16.94)
第五章 模具總體結(jié)構(gòu)設(shè)計(jì)
5.1.凸、凹模間隙值的確定
對(duì)沖件質(zhì)量要求高時(shí)選用較小間隙值,查表3-2
因?yàn)閠取2mm且為中等硬度鋼,所以取Zmin=0.140,Zmax=0.180
表4-14系數(shù)x
表4-15制造公差
5.2.凸、凹模刃口尺寸的確定
①第一道工序?yàn)闆_孔,間隙取在凹模上,則:
4個(gè)凸模同時(shí)沖孔,凸模1加工φ10mm的孔,有凸模2與凸模3加工2個(gè)φ4mm的孔,凸模4加工不規(guī)則形狀的孔
根據(jù)零件形狀,凸模1磨損后尺寸減小
凸模1尺寸:D1T=(D+x△)
查表4-14、4-15得
δT=0.02——凸模制造公差
δA=0.02——凹模制造公差
△=0.1——制件的制造公差
x=0.75——根據(jù)精度在IT11~IT13
Zmin=0.14——最小合理間隙
D1min=10mm——φ10mm孔的最小極限尺寸
D1T=(D+x△)=(10+0.75*0.1)-0.02=10.075-0.02mm
凹模尺寸:用配做法D=(D+x△+zmin)可得
D1A=(10+0.75*0.1+0.14)+0.02=10.215+0.02mm
根據(jù)零件形狀,凸模2磨損后尺寸減小
凸模2尺寸:D2T=(D+x△)
D2T=(D+x△)=(4+0.75*0.1)-0.02=4.075-0.02mm
凹模尺寸:用配做法D=(D+x△+zmin)可得
D2A=(4+0.75*0.1+0.14)+0.02=4.215+0.02mm
根據(jù)零件形狀,凸模3磨損后尺寸減小
凸模3尺寸:D3T=(D+x△)
D3T=(D+x△)=(4+0.75*0.1)-0.02=4.075-0.02mm
凹模尺寸:用配做法D=(D+x△+zmin)可得
D3A=(4+0.75*0.1+0.14)+0.02=4.215+0.02mm
根據(jù)零件形狀,凸模4磨損后各尺寸均減小
凸模4尺寸::D4T=(D+x△)
D4T=(D+x△)=(4+0.75*0.1)-0.02=4.075-0.02mm
L1T=6-0.02mm
L2T=4.075-0.02mm
凹模尺寸:用配做法D=(D+x△+zmin)可得
D4A=(4+0.75*0.1+0.14+0.02=4.215+0.02mm
L1A=6+0.02mm
L2A=4.215+0.02mm
②第二道工序?yàn)槁淞?,間隙取在凸模部分上,則:
根據(jù)零件形狀,凹模磨損后尺寸增大的是D1、D2,不變的是L1、L2
凹模尺寸:D=(D-x△)
D1A=(D-x△)=(20-0.75×0.1)0.035=19.925+0.035mm
D2A=(D-x△)=(62-0.75×0.1)+0.035=61.925+0.035mm
L1A=85.16mm
L2A=13.58mm
凸模尺寸:用配做法D=(D-x△-zmin)可得
D1T=(20-0.75*0.1-0.14)-0.025=19.785-0.025mm
D2T=(62-0.75*0.1-0.14)-0.025=61.785-0.025mm
L1T=85.16mm
L2T=13.58mm
5.3主要零部件的設(shè)計(jì)
5.3.1沖孔凸模
凸模1
①凸模長度L=h1+h2+h3+h=31+15+6+19=71mm
h1——凸模固定板厚度,是凹模厚度的0.6~0.8倍,取31mm
h2——卸料板厚度15mm
h3——導(dǎo)尺厚度6~8mm
h——增加長度,取20mm
②凸模形狀如圖5-1
圖5-1 凸模1
③凸模1刃口尺寸為
DT=(D+x△)=(10+0.75*0.1)-0.02=10.075-0.02mm
④凸模強(qiáng)度校核:
承壓能力校核
φ10mm孔:dmin=10.055=4*2*325/1000=2.6
Dmin——凸模最小直徑,為10.055mm
t ——材料厚度,為2mm
τ——材料抗剪強(qiáng)度,為325MPa
σ——凸模材料的許用應(yīng)力(MPa), 對(duì)一般工具鋼,凸模淬火硬度HRC 為58~62時(shí),取1000~1600MPa
抗縱向彎曲能力校核
Lmax=33=3.14*√2*2.2*105*π*44/(64*26533)=45.32
E——凸模材料的彈性模數(shù),一般模具鋼為2.2×105MPa;
P——沖裁力(N);
Lmax——凸模上可能發(fā)生失穩(wěn)彎曲部分長度L的最大值;
a——凸模前端導(dǎo)向情況的系數(shù),無導(dǎo)向,a=1,有導(dǎo)向,a=2;
J——凸模最小橫斷面的慣性矩(mm),圓形凸模: J=πd4/64
綜上:凸模1強(qiáng)度符合生產(chǎn)使用要求
凸模2、凸模3
①凸模長度L=h1+h2+h3+h=31+15+6+19=71mm
②凸模形狀如圖5-2
圖5-2 凸模2、凸模3
③凸模2、3刃口尺寸為
DT=(D+x△)=(4+0.75*0.1)-0.02=4.075-0.02mm
④凸模強(qiáng)度校核:
承壓能力校核
Φ4mm孔:dmin=4.055=4*2*325/1000=2.6
Dmin——凸模最小直徑,為4.055mm
抗縱向彎曲能力校核
Lmax=33=3.14*√2*2.2*105*π*44/(64*10613)=71.65mm
綜上:凸模2、凸模3強(qiáng)度符合生產(chǎn)使用要求
凸模4
①凸模長度L=h1+h2+h3+h=31+15+6+19=71mm
②凸模形狀如圖5-3
圖5-3 凸模4
③凸模4刃口尺寸為
D4T=(D+x△)=(4+0.75*0.1)-0.02=4.075-0.02mm
L1T=6-0.02mm
L2T=4.075-0.02mm
④凸模強(qiáng)度校核:
承壓能力校核
Fmin=30.28=18827/1000=18.827
抗縱向彎曲能力校核
Lmax=33=3.14*√2*2.2*105*π*44/(64*10613)=71.65mm
綜上:凸模4強(qiáng)度符合生產(chǎn)使用要求
5.3.2凸凹模
凸凹模外形尺寸=卸料板厚度+修模量+進(jìn)入凹模深度+彈性體厚度+固定板厚度=15+4+3+14+24=60mm。根據(jù)已經(jīng)計(jì)算的有關(guān)凸凹??诘幕境叽?,參照《沖壓模具簡明設(shè)計(jì)手冊》,設(shè)計(jì)凸凹模如下圖5-4所示。
圖5-4 凸凹模
5.3.3落料凹模
①凹模厚度H=k1k2(P/10)1/3=1.25*1(211951/10)1/3=34.59mm,取凹模厚度為40mm
P——沖裁力(N)
k1——沖裁輪廓長度修正系數(shù),查表4-5,取1.25
k2——凹模材料修正系數(shù),查表4-6,取1
②凹模壁厚C=(1.5~2)H=51.89~69.18mm,取凹模壁厚60mm
③凹模寬度B=b+2c=40+120=160mm
b——沿凹模寬度方向刃口型孔的最大距離
c——凹模壁厚
④凹模長度L=l+2c=105.16+120=225.16mm
l——沿凹模長度方向刃口型孔的最大距離
c——凹模壁厚
根據(jù)工件圖樣,取凹模長度為250mm,寬度為160mm,所以凹模輪廓尺寸為250mm×160mm×40mm,如圖5-5
⑤凹模刃口尺寸為
D1A=(D-x△)=(20-0.75×0.1)+0.0351=19.925+0.035mm
D2A=(D-x△)=(62-0.75×0.1)+0.035=61.925+0.035mm
L1A=85.16mm
L2A=13.58mm
圖5-5 落料凹模
5.3.4凸模固定板
根據(jù)該零件的需求,可以選擇凸模固定板形狀為矩形,與凹模周界一致。取固定板的厚度31mm,為凹模厚度的60%~80%。
固定板與階梯式凸模為H7/n6過渡配合,壓裝后,應(yīng)該把凸模與固定板的端面一起磨平。凸模固定板的零件圖如圖5-6所示。
圖5-6 凸模固定板
5.3.5凸凹模固定板
根據(jù)該零件的需求,可以選擇凸凹模固定板形狀為矩形,與凹模周界一致。取固定板的厚度24mm,為凹模厚度的60%~80%。
凸凹模固定板與凸凹模為H7/n6過渡配合,壓裝后,應(yīng)該把凸凹模與固定板的端面一起磨平。凸凹模固定板的零件圖如圖5-7所示。
圖5-7 凸凹模固定板
5.3.6模架選用
由于該零件是邊緣沖裁,所以采用后側(cè)導(dǎo)柱模架。根據(jù)凹模周界:L=250mm,B=160mm,查文獻(xiàn)表9-46可得:模架的閉合高度H=200~240mm,上模座的規(guī)格為250×160×45,下模座的規(guī)格為250×160×50,導(dǎo)柱的規(guī)格為32×160,導(dǎo)套的規(guī)格為32×105×43。模架選用如圖5-8。
圖5-8 模架
5.3.7模柄
根據(jù)壓力機(jī)的型號(hào)JG23-40和,文獻(xiàn)可查得模柄尺寸的直徑為φ50mm,長度為70mm。根據(jù)模具的大小,可以選用凸緣模柄。
根據(jù)JB/T 7646.3-1994選取模柄為:B50如圖5-9所示。
d=50mm,d1=132mm,L=91mm,L1=23mm,L2=5mm,d2=15mm,d3=91mm,d4=11mm,d5=18mm,h=11mm,配合為H7/h6配合。
圖5-9 凸緣模柄
5.3.8卸料裝置
彈性卸料板
為保證沖孔安全,取厚度15mm,如圖5-10所示。
圖5-10卸料板
卸料螺釘
根據(jù)彈性體的內(nèi)徑、卸料板的厚度及下模座和凸凹模固定板的厚度,查文獻(xiàn)選用圓柱頭內(nèi)六角卸料螺釘,如圖5-11。直徑d=M12mm,長度L=70mm,l=10mm,b=4mm,H=12mm,d1=16mm,d2=24mm,d4=11.4mm。
圖5-11卸料螺釘
5.4模具總裝圖
1-下模座,2-卸料螺釘,3-導(dǎo)柱,4-凸凹模固定板,5-聚氨酯彈性體,6-彈簧,7-活動(dòng)擋料銷,8-導(dǎo)套,9-凹模,10-凸模固定板,11-墊板,12-上模座,13-內(nèi)六角圓柱頭螺釘,14-打桿,15-沖孔凸模2、3,16-推板,17-沖孔凸模4,18-打料桿,19-凸緣模柄,20-沖孔凸模1,21-螺釘,22-銷,23-推件塊,24-凸凹模,25-卸料板,26-螺釘
第六章 壓力機(jī)的校核
6.1公稱壓力的校核
根據(jù)總沖壓力選取壓力機(jī)的型號(hào)為JG23-40,它的公稱壓力為400kN,計(jì)算出的總沖壓力為293.377kN,400kN>293.377kN,所以壓力機(jī)的公稱壓力滿足要求。
6.2裝模高度的校核
沖模的閉合高度H應(yīng)介于壓力機(jī)的最大裝模高度Hmax和最小裝模高度Hmin之間。
Hmax-5mm≥H≥Hmin+10mm
模具閉合高度H=45+10+31+40+2+15+18+24+50=235mm
295mm≥H=235mm≥230mm
沖模閉合高度符合。
第七章 模具裝配要求
7.1保證設(shè)計(jì)參數(shù)
在凸凹模間隙值和公差所允許的范圍中,肯定有凸模安裝后的垂直度偏差。選擇模架時(shí),滑動(dòng)導(dǎo)向副的配合間隙,及其軸線對(duì)軸線對(duì)凸模與凹模組合安裝面的垂直度偏差之和,亦須控制在沖裁間隙及其公差所允許的范圍內(nèi)。
7.2正確裝配組件與零件
安裝于固定板孔內(nèi)的凸凹模與凸凹模固定板,應(yīng)采用H7/n6配合。帶圓柱或帶肩凸模的安裝沉孔的深度,須一致。同時(shí),其凸模圓柱或錐頭頂面,須與固定板底面磨平。為了確定落料、沖孔凹模的刃口高度,從而通常漏料孔比刃口大0.2——2mm,確保暢通無阻。頂料、卸料器運(yùn)動(dòng)靈活。在裝配中,相鄰的兩個(gè)零件連接以及固定時(shí),其接合面務(wù)必密切貼緊。
參考文獻(xiàn)
[1]翁其金主編.沖壓工藝及沖模設(shè)計(jì)[M].第2版.機(jī)械工業(yè)出版社,2013.1
[2]張榮清主編.模具設(shè)計(jì)與制造[M].第2版.高等教育出版社,2008.3
[3]鄧明主編.實(shí)用模具設(shè)計(jì)簡明手冊[M].第1版.機(jī)械工業(yè)出版社,2010.1
[4]夏居諶主編.中國模具設(shè)計(jì)大典[EB/OL].中國機(jī)械工程學(xué)會(huì),2013.1
[5]曹立文主編.新編實(shí)用沖壓模具設(shè)計(jì)手冊[M].第1版.人民郵電出版社,2007.10
[6]鐘翔山主編.沖壓模具設(shè)計(jì)實(shí)例精選[M].第1版.化學(xué)工業(yè)出版社,2012.2
[7]王曉燕主編. 冷沖壓工藝與模具設(shè)計(jì)[M].第1版.化學(xué)工業(yè)出版社,2011.6
[8]薛啟翔主編. 沖壓模具設(shè)計(jì)結(jié)構(gòu)圖冊[M].第2版.化學(xué)工業(yè)出版社,2010.1
[9]鄭可煌主編. 實(shí)用沖壓模具設(shè)計(jì)手冊[M].第1版.宇航出版社,1990.5
[10]許發(fā)樾主編.模具標(biāo)準(zhǔn)化與原型結(jié)構(gòu)設(shè)計(jì)[M].第1版.機(jī)械工業(yè)出版社,2009.7
致謝
在本次畢業(yè)設(shè)計(jì)過程中,我的設(shè)計(jì)工作順利結(jié)束,我要感謝三江學(xué)院。感謝它提供了這么美好的學(xué)習(xí)環(huán)境,給了我學(xué)習(xí)進(jìn)步成長的空間!我的畢業(yè)設(shè)計(jì)課題是:踏板組件沖壓模具設(shè)計(jì),在設(shè)計(jì)過程中,我得到了老師、同學(xué)和父母的大力支持和幫助。
首先,我要感謝魏楓老師。從開始的選題指導(dǎo)、論文框架編排到后面裝配圖的繪制、零件圖的修改,都為我提供了很多寶貴的意見。嚴(yán)謹(jǐn)求實(shí)的治學(xué)態(tài)度和兢兢業(yè)業(yè)的工作作風(fēng)深深感染了我。
其次,我要感謝我的舍友。在設(shè)計(jì)過程當(dāng)中,我有遇到難點(diǎn)都會(huì)與他們交流,做完之后還可以請(qǐng)他幫我檢查改錯(cuò),互幫互助,共同進(jìn)步。同時(shí)在軟件使用、資料搜集上也為我提供了許多的幫助,在此我向他們表示感謝。能與他們在同一屋檐下愉快地學(xué)習(xí)、生活三年將成為我這輩子最美好的回憶。
同時(shí),感謝撰寫參考資料、教材的先輩們。他們在忙碌的生產(chǎn)過程中總結(jié)經(jīng)驗(yàn),積累知識(shí),凝聚智慧,為我的設(shè)計(jì)提供了方向,簡化了步驟,在此衷心感謝他們。
謹(jǐn)以此致謝最后,我要向百忙之中抽時(shí)間對(duì)本文進(jìn)行審閱的各位老師表示衷心的感謝。
24
畢 業(yè) 設(shè) 計(jì)(論 文)任務(wù)書
設(shè)計(jì)(論文)題目: 踏板組件(B)沖壓模具設(shè)計(jì)
學(xué)生姓名:
學(xué) 院:
專 業(yè):
班 級(jí):
學(xué) 號(hào):
指導(dǎo)教師:
下發(fā)任務(wù)書日期: 年12月19日
任務(wù)書填寫要求
1.畢業(yè)設(shè)計(jì)(論文)任務(wù)書由指導(dǎo)教師根據(jù)各課題的具體情況填寫,經(jīng)學(xué)生所在專業(yè)的負(fù)責(zé)人審查、學(xué)院領(lǐng)導(dǎo)簽字后生效。此任務(wù)書應(yīng)在畢業(yè)設(shè)計(jì)(論文)開始前至少一周內(nèi)填好并發(fā)給學(xué)生。
2.任務(wù)書內(nèi)容必須按教務(wù)處統(tǒng)一設(shè)計(jì)的電子文檔標(biāo)準(zhǔn)格式(可從教務(wù)處網(wǎng)頁上下載)打印,要求正文小4號(hào)宋體,1.5倍行距,禁止打印在其它紙上剪貼。
3.任務(wù)書內(nèi)填寫的內(nèi)容,必須和學(xué)生畢業(yè)設(shè)計(jì)(論文)完成的情況相一致,若有變更,應(yīng)當(dāng)經(jīng)過所在專業(yè)及學(xué)院主管領(lǐng)導(dǎo)審批后方可重新填寫。
4.任務(wù)書內(nèi)有關(guān)“學(xué)院”、“專業(yè)”等名稱的填寫,應(yīng)寫中文全稱,不能寫數(shù)字代碼。學(xué)生的“學(xué)號(hào)”要寫全號(hào),不能只寫最后2位或1位數(shù)字。
5.任務(wù)書內(nèi)“主要參考文獻(xiàn)”的填寫,應(yīng)按照《三江學(xué)院畢業(yè)設(shè)計(jì)(論文)撰寫規(guī)范》的要求書寫。
6.有關(guān)年月日等日期的填寫,應(yīng)當(dāng)按照國標(biāo)GB/T 7408—94《數(shù)據(jù)元和交換格式、信息交換、日期和時(shí)間表示法》規(guī)定的要求,一律用阿拉伯?dāng)?shù)字書寫。如“2015年6月26日”或“2015-06-26”。
畢 業(yè) 設(shè) 計(jì)(論 文)任 務(wù) 書
1.本畢業(yè)設(shè)計(jì)(論文)課題應(yīng)達(dá)到的目的:
踏板組件(B)零件是一個(gè)沖壓件,需多道沖壓工序完成生產(chǎn)(落料、沖孔、彎曲......等),本課題不僅要研究其沖壓成形的工藝方案,還要求在完成沖壓模具的設(shè)計(jì)同時(shí)要充分考慮到各沖壓工序之間的銜接。
通過對(duì)本課題的研究,旨在讓學(xué)生綜合應(yīng)用所學(xué)的專業(yè)理論和設(shè)計(jì)方法,參與生產(chǎn)實(shí)踐,以達(dá)到對(duì)沖壓件的成形特性、沖壓成形質(zhì)量的保證有深刻的認(rèn)識(shí)和理解,從而制定合理的沖壓工藝方案并完成模具的設(shè)計(jì)。
2.本畢業(yè)設(shè)計(jì)(論文)課題任務(wù)的內(nèi)容和要求(包括原始數(shù)據(jù)、技術(shù)要求、工作要求等):
1)根據(jù)給出的圖片,完成零件圖的設(shè)計(jì),根據(jù)零件的用途,選擇合適的材料,對(duì)該零件進(jìn)行沖壓工藝性分析,要求合理地滿足沖壓工藝要求;
2)根據(jù)零件圖,要求完成沖壓模具一副(包含兩個(gè)或兩個(gè)以上沖壓工序);(結(jié)構(gòu)形式自己確定);
3)自定生產(chǎn)批量,重點(diǎn)要注意下料展開尺寸的計(jì)算準(zhǔn)確性,最大限度的提高材料利用率,凸、凹模的間隙值的選擇,零件壓力中心的確定,在選擇設(shè)備時(shí)要注意設(shè)備開模行程、工作臺(tái)面尺寸與模具的關(guān)系等;
4)模具設(shè)計(jì)時(shí)要嚴(yán)格按照國家標(biāo)準(zhǔn)選用公差、技術(shù)參數(shù)和模架;要求用CAD完成圖紙的設(shè)計(jì);
5)完成二維裝配圖和主要部分零件圖,圖紙總數(shù)量要大于折合的兩張零號(hào)圖;
6)完成論文的撰寫、修改和定稿。
畢 業(yè) 設(shè) 計(jì)(論 文)任 務(wù) 書
3.對(duì)本畢業(yè)設(shè)計(jì)(論文)課題成果的要求〔包括圖表、實(shí)物等硬件要求〕:
按畢業(yè)設(shè)計(jì)的時(shí)間節(jié)點(diǎn)要求按期完成:
1)完成與本專業(yè)相關(guān)的英文翻譯一篇數(shù)量要求在3000漢字以上,并附原文,原文為PDF格式;
2)開題報(bào)告一份,總字?jǐn)?shù)不少于3000漢字;
3)撰寫4000漢字以上的畢業(yè)論文一份,中文摘要300漢字左右,外文摘要約250個(gè)詞左右,格式應(yīng)符合規(guī)范化要求;
4)完成總裝圖和主要零件圖設(shè)計(jì),圖紙總數(shù)量折合2張A0號(hào)圖紙;
5)交付相關(guān)的電子文檔及紙質(zhì)圖紙,提交論文紙質(zhì)查重報(bào)告,查重率應(yīng)低于30%;
6)整個(gè)畢業(yè)設(shè)計(jì)過程最少要填寫8份畢業(yè)設(shè)計(jì)(論文)指導(dǎo)情況記錄表。
4.主要參考文獻(xiàn):
[1]翁其金.冷沖壓工藝及沖模設(shè)計(jì)[M].北京,機(jī)械工業(yè)出版社.2012
[2]冷沖壓模具改進(jìn)設(shè)計(jì)實(shí)例分析[J]. 陳克忠.企業(yè)科技與發(fā)展.2013(08)
[3]2017沖壓工藝與模具成型前沿技術(shù)報(bào)告會(huì)成功舉辦[J].模具制造.2017(07),2008
[4]筒形件的沖壓工藝及模具設(shè)計(jì)[J]. 崔志強(qiáng).現(xiàn)代國企研究. 2015(08)
[5] Watson I.Case-based reasoning is a methodology not a
technology[J].
[6]冷沖壓模具改進(jìn)設(shè)計(jì)實(shí)例分析[J]. 陳克忠. 企業(yè)科技與發(fā)展. 2013(08):26-30
畢 業(yè) 設(shè) 計(jì)(論 文)任 務(wù) 書
5.本畢業(yè)設(shè)計(jì)(論文)課題工作進(jìn)度計(jì)劃:
起 訖 日 期
工 作 內(nèi) 容
5.本畢業(yè)設(shè)計(jì)(論文)課題工作進(jìn)度計(jì)劃:
起 訖 日 期
工 作 內(nèi) 容
2019年12月20日-2019年12月27日
指導(dǎo)教師對(duì)學(xué)生當(dāng)面下發(fā)任務(wù)書,并對(duì)課題內(nèi)容進(jìn)行講解,提出具體的任務(wù)要求,根據(jù)老師的指導(dǎo)意見,要求學(xué)生定期填寫指導(dǎo)意見表并對(duì)照進(jìn)度計(jì)劃表同步自查完成進(jìn)度。
2019年12月28日-2020年1月10日
學(xué)生搜集資料,熟悉課題要完成的內(nèi)容,提交開題報(bào)告及外文翻譯的初稿。
2020年1月11日-2020年2月28日
提交開題報(bào)告、外文參考資料及譯文的定稿,對(duì)老師指出的問題在規(guī)定時(shí)間內(nèi)及時(shí)修改,所有的格式必須滿足畢設(shè)要求。
2020年3月1日-2020年3月25日
進(jìn)一步完善前期的各項(xiàng)材料,進(jìn)行畢業(yè)設(shè)計(jì)的課題研究、具體方案設(shè)計(jì)等工作,具體要求:結(jié)合課題選擇一付典型模具進(jìn)行分析,選擇一本合適的設(shè)計(jì)手冊,按設(shè)計(jì)步驟進(jìn)行計(jì)算說明書的撰寫,徒手繪制模具草圖開始模具圖的設(shè)計(jì),圖中必須標(biāo)注尺寸(包括壓力中心、工作部分相關(guān)尺寸、閉合高度等)。
2020年3月26日- 2020年4月10日
對(duì)照計(jì)算說明書,開始正式的CAD總裝圖圖紙繪制,并準(zhǔn)備畢設(shè)中期檢查。
2020年4月11日- 2020年4月25日
進(jìn)一步完成課題的各項(xiàng)工作如:零件圖的拆分、論文的修改、答辯PPT的準(zhǔn)備等,并完成畢業(yè)論文的初稿。
2020年4月26日- 2020年5月10日
進(jìn)行畢業(yè)論文查重、評(píng)閱工作,學(xué)生根據(jù)要求完成論文定稿,準(zhǔn)備畢業(yè)論文答辯。
所在專業(yè)審查意見:
同意
專業(yè)(系)負(fù)責(zé)人:
2019年12月26日
學(xué)院審查意見:
同意
學(xué)院負(fù)責(zé)人:
2020年1月8日
畢業(yè)設(shè)計(jì)(論文)外文資料翻譯
設(shè)計(jì)(論文)題目: 踏板組件(B)沖壓模具設(shè)計(jì)
學(xué)生姓名:
學(xué) 院: 機(jī)械與電氣工程學(xué)院
專 業(yè): 材料成型及控制工程
班 級(jí):
學(xué) 號(hào):
指導(dǎo)教師:
外文出處:
年2月27日
1.外文資料翻譯譯文(約3000漢字):
模具設(shè)計(jì)手冊
伊凡娜·蘇奇
14-8 表面清潔
制造的金屬零件可能含有潤滑劑、車間污垢和灰塵、磨料、材料碎片和大量其他雜質(zhì)或污染物的殘留物。通常,這些零件必須清潔,以便為某些其他精加工過程(如噴漆或其他涂層應(yīng)用)準(zhǔn)備表面。
選擇合適的清洗方法必須考慮到許多因素。首先,必須確定要清除的臟物或污染物的類型,因?yàn)榍宄椭璧谋砻媲鍧嵎椒ㄅc清除金屬碎屑所需的方法不同。必須考慮成品零件的表面要求,要避免損害產(chǎn)品的某些特殊特性。例如,某些金屬板五金件的開口不應(yīng)去毛刺,因?yàn)橐粋?cè)的粗糙度對(duì)其安裝很重要。
此外,在考慮到特定公司或工廠的清潔能力的情況下,必須針對(duì)后續(xù)的精加工過程對(duì)問題進(jìn)行評(píng)估。
這有幾種零件清潔方法,每種方法使用不同的原理,每種方法適用于不同的清潔應(yīng)用范圍。有些通過機(jī)械手段清除要去除的元素;另一些則使用化合物、蒸汽或電解質(zhì)、超聲波、鹽浴和其他變化來解決。下面列出了這些清洗過程的主要類別。
14-8-1機(jī)械清洗
機(jī)械清洗利用磨料和其他物體的機(jī)械作用,用于研磨、拋光、拋光、噴砂清理或噴丸處理等過程。磨料顆??梢允歉稍锏?,也可以是包含在液體中的,并應(yīng)用于零件表面。機(jī)械清潔中使用的其他物體可以是任何東西,如碎布、玻璃珠或拋光劑。
這種清潔方法可用于清除污垢、鐵銹、飛邊、零件去毛刺或僅用于表面粗加工以進(jìn)行后續(xù)精加工。實(shí)際操作程序取決于特定部分和預(yù)期結(jié)果。
振動(dòng)清洗常用于小型金屬?zèng)_壓件,這些零件與以小石子或類似材料為形式的磨具混合,放置在振動(dòng)或旋轉(zhuǎn)的大滾筒中。零件和研磨元件的同時(shí)移動(dòng)能夠去除毛刺、平滑表面,并在一定程度上精加工邊緣和去除其銳度。較大尺寸的零件可以通過一個(gè)設(shè)備擦洗他們的表面,通過與砂帶接觸這種研磨方法來去毛刺和表面清潔。
噴砂清理使用磨料顆粒,將其推到要清理的零件上。它是一種用于黑色和有色金屬鍛件和鑄件或焊接件等的清洗方法。
噴丸與噴砂的不同之處在于,噴丸的清潔作用僅僅是對(duì)其提高材料疲勞強(qiáng)度的補(bǔ)充。這種類型的表面處理也能消除否則會(huì)產(chǎn)生應(yīng)力腐蝕開裂的拉伸應(yīng)力。在噴丸處理中,靠在零件上的物體不是由磨料引起的,它們通過產(chǎn)生大量的淺凹痕來攻擊表面,這使得該過程很容易與材料表面的冷加工相媲美。
所有的注重尺寸的零件都要用玻璃珠清潔表面。作為一種清潔方法,它優(yōu)于在液體中使用研磨泥漿。玻璃珠清潔可用于準(zhǔn)備噴漆、釬焊、焊接和其他類似的制造工藝。它產(chǎn)生啞光飾面,因此也可用于裝飾目的。用玻璃珠清潔的一個(gè)決定性的優(yōu)點(diǎn)是,在清潔表面時(shí),不會(huì)去除可測量的尺寸量。
14-8-2堿性清洗
最常用的工業(yè)清洗方法是堿性清洗,其作用基本上是物理和化學(xué)的,輔之以表面活性劑、乳化劑、分離劑、皂化劑和潤濕劑的組合,所有這些都會(huì)清洗部件。溶液可以通過攪拌來加熱。
可溶解的污垢顆粒被沖走。固體顆粒從零件中分離出來,允許在底部的污泥中沉淀,或通過過濾和類似程序從溶液中漂浮并去除。
堿性清洗可用于清除蠟類固體、金屬顆粒、油、油脂、灰塵和其他污染物。該工藝的應(yīng)用是將零件浸泡在液體中或通過噴霧或乳化。這樣的清洗過程通常要經(jīng)過水洗和干燥循環(huán)。
14-8-3電解清洗
該工藝是一種特殊類型的浸沒清洗,工藝中包含電極。直流電通過溶液傳導(dǎo),待清洗部分作為陽極,而電極作為陰極。有些工藝交替使用陰極-陽極名稱。在清洗周期中,氧氣在陽極處的凈化作用可能進(jìn)一步有助于操作。
這種類型的清潔可用于除銹、準(zhǔn)備磷化、鉻酸鹽處理、噴漆,特別是電鍍,后者要求更高的清潔度。
14-8-4乳化液清洗
這一過程使用兩種基本材料,它們彼此不溶,例如水和油,并結(jié)合一種能夠迫使它們?nèi)榛娜榛瘎_@種類型的清洗用于嚴(yán)重污染的零件,通常在循環(huán)后進(jìn)行堿性清洗,以最終去除非常微小的污染物。
乳化劑有兩種:(1)有助于在水中形成由溶劑組成的乳狀液,和(2)有助于在溶劑中形成由水組成的乳液的乳化劑。
常用的乳化劑有非離子聚醚、烴磺酸鹽、胺皂、胺鹽、甘油或多元醇。溶劑通常來源于石油,如環(huán)烷烴(煤油)。
14-8-5溶劑清洗
這種清洗方法包括將溶劑應(yīng)用于有機(jī)污染物,如油或油脂,以試圖將它們從零件表面去除。有時(shí),為了去除零件表面的溶劑,這種清洗必須進(jìn)行堿洗。這種清洗也可用于去除電鍍零件上的水。
溶劑可以是石油基(如石腦油、礦油或煤油)或氯化烴(三氯甲烷、三氯乙烯、二氯甲烷)或醇(異丙醇、甲醇、乙醇)。其他溶劑包括但不限于苯、丙酮和甲苯。
清潔機(jī)制主要適用于有機(jī)污染物,如油脂或油。這些雜質(zhì)很容易溶解和去除,或從零件表面沖洗掉。
14-8-5-1蒸汽脫脂
溶劑蒸汽脫脂是溶劑清洗的一個(gè)專業(yè)分支。它使用氯化或氟化溶劑去除油脂、蠟或油等雜質(zhì)。將要脫脂的物體放在一個(gè)罐中,在這個(gè)罐中有一種溶劑是煮沸的。物體通過蒸汽的作用而脫脂,蒸汽比空氣重,從而使后者從油箱容積中排出。到達(dá)上部冷卻器區(qū)域后,這些加熱的蒸汽冷凝并滴回到加熱的地方。
14-8-6酸洗
酸洗使用含有有機(jī)酸、礦物酸和酸鹽的各種溶液,與潤濕劑和洗滌劑結(jié)合用于鋼鐵的清洗。這種C傾斜法可以用來除去油、油脂、氧化物和其他污染物,而不需要額外加熱。
酸浸洗和酸洗是非常相似的工藝,酸浸洗是更積極的處理,用于清除鍛件或鑄件和各種半成品的氧化皮。
無機(jī)酸和無機(jī)鹽很多,它們形成無機(jī)(礦物)酸溶液或酸鹽溶液或酸溶劑混合物。這些清洗液的有機(jī)成分可以是草酸、酒石酸、檸檬酸、乙酸和其他酸,以及酸鹽,例如硫酸鈉、氟化氫鹽或磷酸鈉。此過程中使用的溶劑可以是乙二醇或單丁基(和其他)醚。
14-8-7酸洗
金屬材料的酸洗去除了零件表面的氧化物或結(jié)垢。它也可用于去除其他污染物,方法是將零件浸入酸的液體溶液中。這種溶液的成分、溫度和成分的選擇可能不同,最常見的酸洗液是硫酸。在需要鍍鋅前蝕刻的地方使用鹽酸。不銹鋼的酸洗采用硝酸-氫氟酸。
酸洗的機(jī)理是氧化皮穿透裂紋,酸洗液與金屬發(fā)生化學(xué)反應(yīng)。為了使酸洗液不腐蝕基底金屬,加入了以明膠、面粉、膠水、石油污泥等物質(zhì)形式存在的抑制劑。緩蝕劑可以減少鐵表面的損失,減少氫脆的范圍,同時(shí)保護(hù)金屬不受點(diǎn)蝕的影響,點(diǎn)蝕可能發(fā)生在酸洗過度的地方。
14-8-8 鹽浴除垢
鹽浴除垢工藝用于除垢,必須先進(jìn)行酸洗或酸浸洗才能徹底除垢。鹽浴除鱗可分為三類:氧化型、還原型和電解法。該模式甚至可以與前兩個(gè)過程一起使用。
氧化型鹽浴除鱗是最常用的除垢方法,因?yàn)樗暮唵涡裕词闺娊夥ㄌ峁└蟮某改芰?。還原法的優(yōu)點(diǎn)是鹽浴溫度較低。
去除的水垢與除鱗鹽一起,形成不溶性污泥,必須用機(jī)械方法去除。因此,這些雜質(zhì)可以沉淀在一個(gè)平底鍋中,然后放在那里收集。
14-8-9超聲波清洗
當(dāng)超聲波能量應(yīng)用于氯化烴溶劑溶液、水和表面活性劑或任何其他清潔溶液類型時(shí),將促進(jìn)清潔過程、清除各種污染物。它可用于在材料中去除薄顆粒,或清除復(fù)雜部件、貴金屬、或封閉單元,并用于清除需要極度清潔的地方。
超聲波工藝的缺點(diǎn)是成本高,這是因?yàn)樵O(shè)備的初始成本和維護(hù)成本要高得多。然而,這種類型的清潔被發(fā)現(xiàn)是有益的,因?yàn)橐郧爸挥惺止で鍧嵎椒ā?
14-9表面涂層
選擇表面涂層時(shí),應(yīng)考慮其必須覆蓋的基本金屬。一些涂層被用作防止磨損、腐蝕、氧化以及許多其他原因的保護(hù)。表面涂層在基本金屬本身和環(huán)境之間形成屏障,有時(shí)對(duì)其穩(wěn)定性有害。有涂層可以改變摩擦性能,增強(qiáng)零件的美觀性。各種涂層可用于各種應(yīng)用,但最常用于保護(hù)基本金屬(基本產(chǎn)品)免受外部影響。
即使是組件內(nèi)的兩個(gè)金屬部件也能夠通過形成電偶電池來相互影響,這如果選擇不當(dāng),基本材料可能對(duì)其涂層產(chǎn)生不利的反應(yīng)。因此,在選擇涂層的保護(hù)類型和保護(hù)量時(shí),必須考慮對(duì)形成電偶的可能性的評(píng)估。這涉及到涂層的性質(zhì)是朝其下面的金屬陰極還是陽極。
例如,即使鎳對(duì)鐵是陰極的,而鋅是陽極的,鋼也可以通過鎳或鋅涂層免受其他影響。鎳通過成功地阻止外部腐蝕環(huán)境對(duì)材料的影響來保護(hù)鋼,為此,這種涂層必須沒有氣孔。鋅比鋼更容易腐蝕,而腐蝕性反應(yīng)的副產(chǎn)物,氧化鋅,相當(dāng)大,損害腐蝕過程并保護(hù)涂層材料。
許多金屬能夠形成氧化膜,當(dāng)其穩(wěn)定時(shí),作為該特定材料的保護(hù)涂層。鋁氧化物在酸性環(huán)境中生長,在那里形成厚的保護(hù)層,但一旦堿性合金陽極氧化,涂層收縮,變薄,堅(jiān)硬,穩(wěn)定。一些氧化劑,如錫、鋅、鈦和其他的氧化劑,可以通過額外的化學(xué)或電化學(xué)處理來穩(wěn)定,這將使它們成為基本金屬材料的保護(hù)層。
這種保護(hù)的成功取決于對(duì)原電池過程的正確分析,在此過程中,陽極溶解的金屬必須受到相等和相反的陰極反應(yīng)的保護(hù)。
14-9-1電鍍
電鍍過程實(shí)際上應(yīng)該被稱為電離,因?yàn)樗秒婂兞慵碗婂儾牧现g的電偶原理將材料顆粒轉(zhuǎn)移到零件表面。在這一過程中,直流電被施加到金屬鹽溶液中,在該溶液中沉積待涂覆的零件。這些部分通過連接到能源的負(fù)端,承擔(dān)起陰極或負(fù)極的作用。大型部件懸掛在連接電源負(fù)極的銅棒上,小部件(如墊圈或螺栓)放置在金屬絲籃中。涂層金屬本身充當(dāng)陽極,并以板、棒或擠壓形狀添加到鍍液中。
當(dāng)受電流影響時(shí),陽極金屬材料緩慢電離,其粒子進(jìn)入鍍液。這些離子向陰極極化部分移動(dòng),在陰極極化部分表面以金屬晶體的形式沉積。某些類型的金屬涂層工藝要求對(duì)涂層浴進(jìn)行加熱,有時(shí)添加液體攪拌作用以提高薄膜的均勻性。
涂層的發(fā)展速度取決于電流強(qiáng)度和鍍液溫度。如果鍍液溫度更高或電流的安培數(shù)更大,則涂層過程變得更快。但是,如果強(qiáng)度過高或溶液溫度過高,涂層會(huì)變得粗糙和不充分。電流必須是低電壓的(通常幾伏就足夠了),但強(qiáng)度必須相當(dāng)高,每平方英尺涂層表面的電流為0.1到2安培或更多。
有機(jī)化合物有時(shí)被添加到鍍液中,它們的微量在很大程度上改變了涂層的性能。它們的影響主要是朝向美觀的外觀,隨后對(duì)涂層表面進(jìn)行平滑處理,使其具有光澤。這些嚴(yán)格意義上的光學(xué)增強(qiáng)被它們提供的防腐保護(hù)減弱所抵消。
幾乎所有的金屬都可以用現(xiàn)代方法和現(xiàn)代技術(shù)作為涂層進(jìn)行電鍍。然而,對(duì)于一些人來說,這個(gè)過程是如此昂貴,以至于它仍然只是一個(gè)技術(shù)上的好奇心。
最常見的四種鍍鋅工藝是:
l酸性電偶涂層,其中金屬以陽離子形式存在于簡單的鹽溶液中,例如硫酸鹽、硫酸鹽、氟硼酸鹽或氯化物的溶液中。該工藝用于鎳、銅、鋅和錫涂層的應(yīng)用。
l復(fù)雜的堿性氰化物浴,帶有陰離子形式的金屬顆粒,連接到溶液的氰化物部分。這種類型的鍍液用于銅、鎘、鋅、銀和金涂層的應(yīng)用。
l復(fù)雜酸浴,其中陰極沉積通過中間階段實(shí)現(xiàn),或作為陰極膜。鉻酸就是一個(gè)例子,它能形成單重鉻酸鹽離子。
l金屬的堿性浴,形成兩性氧化物,如錫酸鈉浴,含有錫酸鈉或錫酸鹽,用羥基離子來穩(wěn)定。
2.外文資料原文(與課題相關(guān),至少1萬印刷符號(hào)以上):
Handbook of Die Design
Ivana Suchy
14-8 SURFACE CLEANING
Metal parts, as manufactured, may contain residues of lubric ants, shop dirt and dust, abrasives, splinters of materials, and a host of other impurities or contaminants. Often these parts have to be cleaned in order to prepare the surface for some other finishing process, such as painting or other coating application.
The proper cleaning method of such parts must be well chosen, with many factors in mind. First, the type of soil or contaminant to be removed has to be identified, since a different method of surface cleaning is needed for removal of grease than for metal chips. The surface requirements of the finished part must be taken into account in order not to use a method which may become detrimental to some special feature of the product. As an example, openings for certain sheet-metal hardware should not be deburred, as the roughness of one side is important for its installation.
Further, the problem has to be assessed with regard to the subsequent finishing processes, while bearing in mind the cleaning capacities of the particular company or plant.
There are several methods of parts cleaning, each using a different principle and each being applicable to a different range of cleaning applications. Some attack the elements to be removed by mechanical means; others use chemical compounds or steam or electrolytes or ultrasound, salt baths, and other variations. Main categories of these cleaning processes are listed below.
14-8-1 Mechanical Cleaning
Mechanical cleaning utilizes a mechanical action of abrasives and other objects, which are used in processes such as those of grinding, polishing, buffing, blast cleaning, or shot peening. Abrasive particles may be either dry or as contained in a liquid and applied against the surface of the part. Other objects used in mechanical cleaning may be anything from rags up to glass beads or buffing compounds.
This type of cleaning method may be used for removal of dirt, rust, flash, for deburring of parts, or just for roughing of the surface for subsequent finishing. The actual procedure depends on the particular part and the expected outcome.
Vibration cleaning is frequently used for small metal- stamped parts, where these are mixed with abrasives in the form of small stones or similar materials and placed in large drums, which are either vibrating or rotating. The simultaneous movement of parts and abrasive elements is capable of remov ing burrs, smoothing the surface, and to some degree finishing the edges and removing their sharpness. Larger-sized parts are deburred and surface-cleaned by an abrasive method of running them through an equipment which scrubs their surface by contact with an abrasive belt.
Blast cleaning uses abrasive particles, propelling them against the part to be cleaned. It is a cleaning method used with ferrous and nonferrous forgings and castings or to clean weldments, and so on.
Shot peening differs from blast peening in that its cleaning action is merely an addition to its actual purpose of improving the fatigue strength of the material. This type of finishing is also capable of relieving tensile stresses that would otherwise produce stress-corrosion cracking. In shot peening, the objects propelled against the part are not of abrasive origin.They attack the surface by creating a multitude of shallow indents, which makes the process easily comparable to cold working of the material surface.
Cleaning of the surface with glass beads is used for parts of all sizes. As a cleaning method, it surpasses that using an abrasive slurry within a liquid. Glass bead cleaning may be utilized in preparation for painting, brazing, welding, and other similar manufacturing processes. It produces a matte finish, for which reason it may also be used for decorative purposes. A definitive advantage of cleaning with glass beads is that while the surface is being cleaned, no measurable amount is removed.
14-8-2 Alkaline Cleaning
The most often used industrial cleaning method is alkaline cleaning, the action of which is basically physical as well as chemical, aided by combinations of surfactants, emulsifiers, separating agents, saponifiers, and wetting agents all attacking the part to be cleaned. The solution may be heated or agitated in motion by stirring.
Dissolvable particles of dirt are washed away. Solid particles are separated from the part and allowed to either settle in the fom of sludge to the bottom or be floated away and removed from the solution by means of filtering and similar procedures.
Alkaline cleaning may be used for removal of wax-type solids, metallic particles, oil,grease, dust, and other contaminants. The application of the process is by immersion in liquid or by spraying or emulsification. Such a cleaning process is often followed by a water rinse and a drying cycle.
14-8-3 Electrolytic Cleaning
This process is a specialized type of immersion cleaning, with the inclusion of electrodes within the process. A direct current is conducted through the solution, where the part to be cleaned serves as the anode while the electrode acts as the cathode. Some processes alternate the cathode-anode designation. The cleansing action of oxygen, which develops at the anode during the cleaning cycle, may further aid the operation.
This type of cleaning may be used for removal of rust, in preparation for phosphating,chromating, painting, and especially for electroplating, the latter demanding a higher degree of cleanliness.
14-8-4 Emulsion Cleaning
This process uses two basic materials, insoluble within each other, such as water and oil, combined with an emulsifying agent capable of forcing them to emulsify. This type of cleaning is used with heavily soiled parts, and the cycle is usually followed by alkaline cleaning for final removal of very minute contaminants.
Emulsifiers are of two types: (1) emulsifiers that aid the formation of emulsion which consists of a solvent in water, and (2) emulsifiers that aid the formation of emulsion which consists of water in solvent.
Frequently used emulsifiers are nonionic polyethers, hydrocarbon sulfonates, amine soaps, amine salts, glycerols, or polyalcohols. Solvents usually are of petroleum origin,such as naphthenic hydrocarbons (kerosene).
14-8-5 Solvent Cleaning
This cleaning method consists of an application of solvents to the organic contaminants such as oils or grease, in an attempt to remove them from the surface of parts. Sometimes such cleaning has to be followed by an alkaline wash, in order to remove the solvent itself from the part surface. This type of cleaning may also be used for removal of water from electroplated parts.
Solvents may be either petroleum-based (such as naphtha, mineral spirits, or kerosene)or chlorinated hydrocarbons (trichloroethane, trichloroethylene, methylene chloride) or alcohols (isopropanol, methanol, ethanol). Other solvents include but are not restricted to benzol, acetone, and toluene.
The mechanism of cleaning is applicable mainly to contaminants of organic origin, such as grease or oils. These impurities may be easily solubilized and removed, or washed off the part s surface.
14-8-5-1 Vapor Degreasing. Vapor degreasing with solvents is a specialized branch of solvent cleaning. It uses chlorinated or fluorinated solvents for removal of soils such as grease, waxes, or oil. The objects to be degreased are placed within a tank, where a solvent
is boiled. Objects are degreased by the action of vapors, which—be ing heavier than air—displace the latter from the volume of the tank. On reaching the upper cooler zones, these heated vapors condense and drip back down where they are reheated.
14-8-6 Acid Cleaning
Acid cleaning uses various solution containing organic acids, mineral acids, and acid salts,combined with a wetting agent and detergent for cleaning of iron and steel. Such a C leaning method may be used to remove oil, grease, oxide, and other contaminants without additional application of heat.
Acid cleaning and acid pickling are quite similar processes, with acid pickling being much more aggressive treatment, used for removal of scale from forgings or castings and from various half- finished mill products.
Mineral acids and salts are numerous, forming either inorganic (mineral) acid solutions or solutions of acid salts or acid-solvent mixtures. Organic components of these cleaning solutions may be oxalic, tartaric, citric, acetic, and other acids, with acid salts such as sodium acid sulfate, bifluoride salts, or sodium phosphates. Solvents used in this process may be ethylene glycol or monobutyl (and other) ethers.
14-8-7 Pickling
Pickling of metal materials removes the oxides, or scale, off the surface of parts. It may be used for removal of other contaminants as well, by immersing the parts in a liquid solution of acid. Such a solution may vary in its composition, temperature, and selection of ingredients, the most common pickling bath being sulfuric acid. Hydrochloric acid is utilized where etching prior to galvanizing is needed. For pickling of stainless steel,nitric-hydrofluoric acid is used.
The mechanism of pickling is that of a penetration of the scale through the cracks and chemical reaction of the pickling solution with the metal underneath. In order for the pickling solution not to attack the base metal, inhibitors in the form of gelatin, flour, glue, petroleum sludge, and other substances are added. Inhibitors can minimize the loss of iron surface and reduce the range of hydrogen embrittlement while protecting the metal from pitting, which may occur where pickling becomes excessive.
14-8-8 Salt Bath Descaling
The salt bath descaling process is used for removal of scale and it must- for a complete removal—be followed by acid pickling or acid cleaning. Salt bath descaling may be divided into three groups: oxidizing type, reducing type, and an electrolytic method. Thelatter may be used even in conjunction with the previous two processes.
Oxidizing type of salt bath descaling is the most often used method of scale removal because of its simplicity, even though the electrolytic method offers greater scale-removing capabilities. The reducing method's advantage is lower temperatures of the salt bath.
The removed scale, along with the descaling salts, forms an insoluble sludge, which must be taken out mechanically. For that reason such impurities are allowed to settle into a pan placed there for their collection.
14-8-9 Ultrasonic Cleaning
Ultrasonic energy, when applied to the solution of chlorinated hydrocarbon solvents or to water and surfactants or to any other type of cleaning solution, will boost the cleaning process, removing various types of contaminants. It may be used for removal of fine particles embedded within the material, or for cleaning of complex parts, precious metals, or sealed units, and also for cleaning where extreme cleanliness is required.
The disadvantage of the ultrasonic process is its high cost, which is due to the much higher initial cost of the equipment and its maintenance. However, this type of cleaning has been found beneficial where previously only hand-cleaning methods worked.
14-9 SURFACE COATING
Surface coating should be chosen with regard to the application it has to serve, along with a consideration for the basic metal it has to cover. Some coatings are used as a protection against abrasion, corrosion, oxidation, and for a host of other reasons. Surface coating creates a barrier between the basic metal itself and the environment, sometimes detrimental to its stability. There are coatings to alter the frictional properties and to enhance the an aesthetic appeal of the part. V arious coatings may be used for various applications but are most often chosen to protect the basic metal, the basic product, from outer influences.
Even two metallic parts within an assembly are capable of attacking each other by forming a galvanic cell, the same way a basic material may react adversely to its coating if chosen improperly. Evaluation of the possibility of a galv anic couple formation must therefore be considered when choosing the type and amount of protection a coating should ofer.This involves a survey of whether the coating is in its nature cathodic or anodic toward the metal underneath it.
For example, a steel may be protected from other influences by nickel or zinc coating,even though nickel is cathodic to iron and zinc is anodic. Nickel protects the steel by successfully blocking the influence of the outer corrosive environment on the material, for the purpose of which, such coating must be free of pores. Zinc provides protection by corroding more readily than steel, and a by-product of the corrosive reaction, zinc oxide, being quite sizable, impairs the corrosive process and protects the coated material.
Many metals are capable of forming oxide films, which—when stabilized—act as a protective coating for that particular material. Aluminum oxides thrive in acidic atmospheres,where they form thick protective layers, but once the basic alloy is anodized, the coating shrinks, turning thin, hard, and stable. Some ox ides, such as those of tin, zinc, titanium, and others, could be stabilized by an additional chemical or electrochemical treatment, which will turn them into protective layers for the basic metal material.
The success of such protection depends on proper analysis of the galvanic-cell process,during which an anodically dissolvable metal must be protected by an equal and opposite cathodic reaction.
14-9-1 Electroplating
The electroplating process should actually be called galvanizing, since it uses the principle of a galvanic couple between the plated part and plating material to transfer particles of material to the surface of the part. In this process, a direct electric current is applied to a solution of metal salts in which the parts to be coated are deposited. These parts assume the role of the cathode, or negative pole, by being connected to the negative end of the source of energy. Large parts are left hanging off a copper bar attached to the negative pole of the source, and small items, such as washers or bolts, are placed in wire baskets. The coating metal itself acts as an anode, and it is added to the bath in the form of plates, bars, or extruded shapes.
When affected by the electric current, the anodic metal material slowly ionizes, its particles entering the solution of the bath. These lttle ions travel toward the cathodic-polarized part, on whose surface they become deposited in the form of metal crystals. Some types of metal-coating processes require coating baths to be heated and sometimes a liquidstirring action is added to enhance the uniformity of the film.
The speed of the development of coating depends on the intensity of electric current and temperature of the bath. With a warmer bath or with higher amperage of the current, the coating process becomes faster. However, with too high an in