7塑胶产品模具设计

1、第六章第六章 塑料产品与模具设计塑料产品与模具设计Plastic Part and Mold Design浇注系统设计浇注系统设计Filling System Design模具设计的优先顺序模具设计的优先顺序Priorities of Mold Design浇注系统设计 (Filling System Design)排气系统设计 (Venting System Design)冷却系统设计 (Cooling System Design)脱模系统设计 (Ejecting System Design)浇注系统设计的优先顺序浇注系统设计的优先顺序Priorities of Filling System

2、 Design产品设计 (Part Design)型腔设计 (Cavity Design)浇口设计 (Gate Design)流道设计 (Runner Design)竖浇道设计 (Sprue Design)喷嘴设计 (Nozzle Design)豎澆道Sprue主流道Main Runner成品Part澆口Gate冷料井Cold Slug Well支流道Branch Runner典型的浇注系统典型的浇注系统Typical Filling System壁厚不均是注塑成形中最大的麻烦制造者。 这对薄壁零件尤然。 这些麻烦包括了迟滞现象、短射、凹陷、发赤、喷流、翘曲及长冷却时间等；目前都可用CAE以直

3、接或间接的方式预测。Non-uniform wall thickness is the biggest trouble maker in plastic injection molding. This is especially true to thin-wall part. The troubles, including hesitation, short shot, sink mark, blush, jetting, warpage and long cooling time etc., can be predicted, directly or indirectly, by using

4、 CAE. 壁厚不均壁厚不均Non-uniform Wall Thickness壁厚设计壁厚设计Wall Thickness Design差 Poor较好 Better最好 Best掏空设计掏空设计(1) (1) Coring Out Design (1)改进设计 Improved原设计 Original差 Poor改进 Improved掏空设计掏空设计(2) (2) Coring Out Design (2)气泡或气泡或/ /和凹陷的形成和凹陷的形成Void or/and Sink Mark Forming气泡气泡 ( Void )凹陷凹陷 ( Sink Mark )肋厚和内圆角半径的影响肋

5、厚和内圆角半径的影响The Effect of Rib Thickness & Fillet Radius肋的底部厚度肋的底部厚度Bottom Thickness of RibW0.5W2.5WW1.2WD1.5WD(A)(B)肋的设计肋的设计 ( (一一 ) )Rib Design ( 1 )t t = wall thichness= wall thichnessB = 0.5tB = 0.5tC C = 3 t= 3 tA AA AD = 2 BD = 2 BE = 0.13 mm(radius)E = 0.13 mm(radius)F = 1.5 - 2 degF = 1.5 - 2 d

6、eg假如需要更大的強度假如需要更大的強度, ,可增加肋的數目可增加肋的數目If more strength is required, add additional ribs.If more strength is required, add additional ribs.F FB BD DE EC Ct t 肋的设计肋的设计 ( (二二 ) )Rib Design ( 2 )肋的设计肋的设计 ( (三三 ) )Rib Design ( 3 )与侧壁相连之凸壳与侧壁相连之凸壳( (热塑性塑料热塑性塑料) )Boss at Wall ( Thermoplastics )A A = =凸凸壳附着处

7、壳附着处壁厚壁厚 wall thicknesswall thicknessB B = =凸凸壳壳外外环直径环直径 dia. of boss over radiidia. of boss over radiiC C = 0.5 A= 0.5 AD D = 2 B= 2 BE E = 1 2 deg= 1 2 degF F = 0.13 mm ( radius )= 0.13 mm ( radius )G G = D= DH H = 0.8 A= 0.8 AI I = A / 4= A / 4J J = 2 B= 2 BK K = 0.3 1 J= 0.3 1 JL L = 0.5 A = 0.5

8、 A L LH HA AA AK KE EI IG GJ JD DAFC CB BSection A-A远离侧壁之凸壳远离侧壁之凸壳( (热塑性塑料热塑性塑料) )Boss Away From Wall( Thermoplastics ) A A = =凸凸壳壳附着处壁厚附着处壁厚 wall thickness wall thicknessB B = =凸壳外环直径凸壳外环直径 ( (含底部修整圆弧半径含底部修整圆弧半径) ) dia. of boss over radii dia. of boss over radiiC = 0.5 AC = 0.5 AD = 2 BD = 2 BE E =

9、 1 - 2 deg= 1 - 2 degF F = 0.13 mm ( radius )= 0.13 mm ( radius )G = 0.95 DG = 0.95 DH = 0.3 G min. to G max.H = 0.3 G min. to G max.I I = 0.5 A= 0.5 AH HE EF FD DF FG GC CB BAI I外侧凸壳外侧凸壳Outside Boss AAAAA ( DIA )A ( DIA )B BB = AB = AB= 2A ( max. )B= 2A ( max. )Section A-AEIMr1Where 1/r : 樑的曲率 curv

10、ature of the beamM: 弯曲力矩 bending momentE : 弹性模数 modulus of elasticityI : 断面积对中立轴的惯性矩 moment of inertia of the cross- sectional area with respect to the neutral axisEI : 翘曲刚性 flexural rigidity挠曲刚性挠曲刚性Flexural RigiditycyNeutral Axis?10.8l9.18.519.988.518.48.108.4?9.9812?8.101233platelAIAdbI平板和肋板的比较平板和

11、肋板的比较Comparison between Plain & Ribbed Plates和平板比，若基于相同的惯性矩(刚性)，肋板需料少了43%，I/A却增加了1.79倍。肋板的最大厚度减为平板的1/4 ，使得冷却时间骤降15/16 (94%)。Based on the same moment of inertia (stiffness), ribbed plate needs 43% less material but boost I/A by 1.79 times comparing with plane plate. The maximum thickness of ribbed pl

12、ate is only 1/4 of plain plates; showing a dramatic cooling time reduction of 94% (15/16) .平板和肋板的比较平板和肋板的比较Comparison between Plain & Ribbed PlatesA variety of molded-ininterlocks can add stiffness to thin-wall housing designs.各种一体成形的內锁件能增加薄壳的刚性。结构设计是薄壳成形零件的基础。Structural design is the base of thin-w

13、all molding parts.薄壳成形零件不仅仅是一趋势，而且也是降低成本和提高竞争力的有效途径。Thin-wall molding part is not only a trend but also an effective way to achieve cost reduction and competitiveness increase.结构设计和薄壳成形零件结构设计和薄壳成形零件Structural Design & Thin-wall Molding Parts每增加一个浇口，至少增加一条熔接线，同时增加一个浇口痕迹、增加流道的体积以及增加较多的积风。Every time on

14、e gate is added, one weld line, at least, one gate mark, more runner volume and more air traps will be added.在型腔能够完满充填的前提下，浇口数目是愈少愈好。As long as the cavity is able to be filled appropriately, gates are the less the better.为了减少浇口数目，每一浇口应就塑流力所能及的流长/壁厚比之内，找出可以涵盖最大零件面积的进浇位置。In order to reduce the number

15、of gates, each gate shall be located at where the melt is able to cover maximum part area based on the largest melt flow length/thickness ratio 浇口数目浇口数目The Number of Gates 熔胶波前推进熔胶波前推进Melt-Front Advancement充填方式,积风和熔接线Filling Patterns, Air-Traps and Weld Lines Location熔接线熔接线Weld Lines材料 Material : PC

16、-GF50原设计 Original更改设计 Revised更改浇口位置以重新定位熔接线更改浇口位置以重新定位熔接线Weld Lines Can Be Relocated By Changing Gate Location典型对头熔接线伸张强度保留值典型对头熔接线伸张强度保留值Typical Butt Weld Tensile Strength Retention ValuesMaterialTypeReinforcementTypeTensile StrengthRetention (%)PP0%GF86%PP20%GF47%PP30%GF34%SAN0%GF80%SAN30%GF40%PC0

17、%GF99%PC10%GF86%PC30%GF64%PSF0%GF100%PSF30%GF62%PPS0%GF83%PPS10%GF38%PPS40%GF20%PA660%GF83-100%PA6610%GF87-93%PA6630%GF56-64%熔接线冷料井熔接线冷料井Weld Slug Well对头熔接线 Butt weld熔接线冷料井Weld slug well积风积风Air Traps排气排气Vent大部份热塑性塑料Most ThermoplasticsA 0.08 mmB 3.18 mmC 12.7 mmD 0.25 mm耐隆和聚缩醛 ( POM )Nylon and Acetal

18、 ( POM ) A 0.04 mmB 3.18 mmC 12.7 mmD 0.25 mm进料流道Feed Runner塑料成品Plastic PartAD排气孔VentBSEC. A-ACAA充填均衡充填均衡Flow Balance熔胶波前于同一时间抵达型腔各末端。Melt front reaches the ends of cavity at the same time.原始设计Original Design十二浇口设计十二浇口设计12 Gate Design电子零件置物箱材料 Material：ABS四浇口设计四浇口设计4 Gate Design修正設計Revised Design电子零

19、件置物箱材料 Material：ABS电子零件置物箱四浇口电子零件置物箱四浇口和十二浇口设计比较表和十二浇口设计比较表原始設計修正設計澆口數目124充填時間 (s)22最大射壓 (MPa)58.461.8鎖模力需求 (Ton)950820產品重量 (g)41364136流道系統重量 (g)29498剪切速率剪切速率Shear Rate剪剪 切切 應應 力力shear Stress黏黏 度度viscosity剪剪 切切 速速 率率shear rate剪切应力剪切应力Shear Stress浇口种类浇口种类Gate Types針點澆口Pin Gate扇型澆口Fan Gate潛伏澆口Submarin

20、e Gate邊緣(薄膜)澆口Edge ( Film ) Gate凸片澆口Tab Gate閥澆口Valve Gate環狀澆口Ring Gate导致平直零件的浇口设计导致平直零件的浇口设计Gate Design for Flat Part中心浇口Center Gate扇形浇口Fan Gate最坏的Worst坏的Worse较好的Better最好的Best侧浇口Edge Gate薄模浇口Film Gate浇口设计浇口设计( (减少滞流效应减少滞流效应) )Gate Design to Avoid Hesitation澆口gate薄thin厚thick差的設計Poor好的設計Good薄thin厚thic

21、k澆口gate浇口设计浇口设计( (避免凹陷和气泡避免凹陷和气泡) )Gate Design to Avoid Sink Mark & Void澆口gate澆口gate差的Poor好的Good使用重叠浇口以避免喷流使用重叠浇口以避免喷流Avoid Jetting by Using Overlap Gate差的Poor好的Good正确的浇口位置以避免喷流正确的浇口位置以避免喷流Avoid Jetting by Locating Gate Correctly差的Poor好的Good使用凸片浇口以避免喷流使用凸片浇口以避免喷流Avoid Jetting by Using Tab Gate使用适当的浇

22、口形状以避免喷流使用适当的浇口形状以避免喷流Avoid Jetting by Profiling Gate Properly差的Poor好的Good泵零件(Part, Pump)塑料(Polymer): POM进浇处(Polymer entrance)： 浇口厚(Gate thickness) 1.2mm，模穴厚(Cavity thickness) 3.2mm问题 (Problem)：喷流(Jetting)Poor Design Causing JettingGatePart : Handle, RefrigeratorMaterial : ABSProblem: Jetting Mark G

23、as Pin气辅成型冰箱把手气辅成型冰箱把手浇口及气针入口浇口太小,导致喷流痕产生厚度差异过大,导致二次喷流痕产生R角过小,气体通路接近把手内侧,外侧則因体积收缩造成凹陷痕迹阀浇口阀浇口Valve Gate1. 阀浇口梢 Valve-Gate Pin2. 加热管 Heater3. O型环 #610 0 Ring4. 流道歧管模板 Manifold Plate5. 轴封环 Seal Retainer6. 套筒轴封 Sleeve Seal7. 枕块 Support Pillar8. 油压缸 Hydraulic Cylinder阀浇口阀浇口 ( (一一) )Valve Gate ( 1 )全部阀浇口

24、同时打开时之充填状况Mold filling with all the valve gates ( shut-off gates ) opened at the same time.阀浇口阀浇口 ( (二二) )Valve Gate ( 2 )部份阀浇口推迟打开，改变充填方式Mold filling with delayed valve gate opening; filling pattern, weld lines and air traps are changed.多浇口设计多浇口设计 Multi-Gate Design阀式浇口阀式浇口Valve Gate矩形边缘浇口设计矩形边缘浇口设计

25、Rectangular Edge Gate DesignL = 0.5 0.75 mmW = 澆口寬度 ( mm ) gate width in mmA = 型腔表面積 ( mm ) surface area of cavity in mmn = 材料常數 material constant 0.6 for PE, PS 0.7 for POM, PC, PP 0.8 for CA, PMMA, PA 0.9 for PVC2 22 2h = n th = n th = 澆口厚度( gate thick. in mm )t = 零件壁厚( wall thick. in mm )WWt tL L

26、h h30AnW 扇形浇口设计扇形浇口设计Fan Gate DesignL= 1.3mmW= w= 浇口宽度 mmgate width in mmA= 型腔表面积 mm surface area of cavity in mmn= 材料常数 material constant 0.6 for PE, PS 0.7 for POM, PC, PP 0.8 for CA, PMMA, PA 0.9 for PVC浇口厚度 gate thick. in mmt= 零件壁厚 wall thick. in mm 2 2 30n h1 = n t h2 = wh1/D重叠式浇口设计重叠式浇口设计Overl

27、ap Gate DesignW= w= 澆口寬度 mm gate width in mmA= 型腔表面積 mm surface area of cavity in mmn= 材料常數 material constant 0.6 for PE, PS 0.7 for POM, PC, PP 0.8 for CA, PMMA, PA 0.9 for PVC澆口厚度 gate thick. in mm = nt澆口長度 land length in mm t= 零件壁厚 wall thick. in mm 2 230n L1 = 0.50.75 L2 = h+( w/2 )凸耳浇口设计凸耳浇口设计T

28、ab Gate DesignL= 0.50.75mmW= w= 浇口宽度 mm gate width in mmA= 型腔表面积 mm surface area of cavity in mmn= 材料常数 material constant 0.6 for PE, PS 0.7 for POM, PC, PP 0.8 for CA, PMMA, PA 0.9 for PVC浇口厚度 gate thick. in mm t= 零件壁厚 wall thick. in mm 2 2 30nh1 = n th2 = 0.9 tL = 0.5 0.75 mmd = 浇口直径( mm ) gate di

29、ameter in mmt = 零件壁厚( mm )wall thick. in mmA = 型腔表面积 ( mm ) surface area of cavity in mmn = 材料常数material constant 0.6 for PE, PS 0.7 for POM, PC, PP 0.8 for CA, PMMA, PA 0.9 for PVC针点浇口设计针点浇口设计Pin Gate DesigndLtd0.206n tA4潜伏式浇口设计潜伏式浇口设计Subgate DesignW= w= 浇口宽度 mm gate width in mmA= 型腔表面积 mm surface

30、area of cavity in mmn= 材料常数 material constant 0.6 for PE, PS 0.7 for POM, PC, PP 0.8 for CA, PMMA, PA 0.9 for PVC浇口厚度 gate thick. in mm = ntt= 零件壁厚 wall thick. in mm 30n 23030 15 2515 25 2水力直径水力直径 Hydraulic DiameterPADH4Where DH is the hydraulic diameter 水力直径 A is the cross-sectional area of the flo

31、w流路断面积 P is the wetted perimeter 湿周长水力直径水力直径 Hydraulic Diameter在不同剖面形状，相同断面积下之变化Various runner profiles, based on the same cross-sectional area流道尺寸设计流道尺寸设计 (1)(1)Runner Sizing (1)D : 流道直径 ( mm ) runner diameter in mmW : 下游塑料重量 ( g ) downstream plastic weight L : 流道长度 ( mm ) runner length in mmDWL3.7

32、4流道尺寸设计流道尺寸设计(2)(2)Runner Sizing (2)流道尺寸设计流道尺寸设计(3)(3)Runner Sizing (3)mmDgcmcmcmgWmmLLWD338. 214.144102 . 0/9 . 0307 . 31223114111流道尺寸设计流道尺寸设计(4)(4)Runner Sizing (4)mmDgggcmcmcmgWWmmLLWD533. 466.28219. 014.14243 . 03/9 . 0807 . 322231224222流道尺寸设计流道尺寸设计(A1)(A1)Runner Sizing (A1)G : 重量 weightS : 零件厚度

33、 thicknessD : 参考直径 reference diameterG( g ) D ( mm )for PS, ABS, SAN, CAB流道尺寸设计流道尺寸设计(A2)(A2)Runner Sizing (A2) G( g ) D ( mm )for PE, PP, PA, POMG : 重量 weightS : 零件厚度 thicknessD : 参考直径 reference diameter流道尺寸设计流道尺寸设计(B)(B)Runner Sizing (B)D : 参考直径 reference diameterL : 长度 lengthfL:长度系数 Length coeffi

34、cientD : 流道直径 runner diameterfL LL (mm)D = D fL L冷料井设计冷料井设计Cold Slug Well Design2d次流道Secondary runnerd主流道Primary runner澆口Gate型腔Cavity倒椎度冷料井竖浇道拉料杆Reverse taper cold slug-well sprue pullerZ型冷料井豎澆道拉料桿 Z - taper cold slug-well sprue puller溝型冷料井豎澆道拉料桿Grooved cold slug-well sprue puller冷料井设计冷料井设计Cold Slug

35、 Well Design浇道衬套尺寸浇道衬套尺寸Sprue Bushing Sizing排气系统设计排气系统设计Venting System Design为何排气仍然还是一个问题？Why venting is still a problem ?因为降低射速，让积风有较多的时间逃气，是一件太容易的事。但是Because it is too easy to slow down the injection speed and give the trapped air more time to escape. But .排气排气Vent射速一降，熔胶温度很快降低，射压必须提高，残余应力随之提高，翘曲的

36、可能性增加。 如果想藉提高料温，以降低射压，料温必须升得很高，这样又会引起塑料裂解。When injection speed is lower, melt temperature goes down very fast, injection pressure has to be increased, residual stress is increased and the possibility getting warppage becomes higher. If one would like to increase barrel temperature to reduce the requ

37、ired injection pressure, the barrel temperature has to be increased to a quite high level and polymer degradation would be induced. 排气排气Vent高料温和高射压都说明充填系统有了流动的问题Both high barrel temperature and high injection pressure are indications of flow problem in the filling system.排气排气Vent我们常发现: 射速提高时，塑料表现得更为

38、出色。It is quite common that material performs better when it is injected faster.最适化螺杆速度充分运用摩擦热，将塑流保持在最佳状态。许多充填和翘曲的问题也就迎刃而解。An optimized ram speed profile fully uses the friction heat to keep the best flow characteristics, which corrects many of the fill and warpage problems.排气排气Vent有了适当的排气，射速可以提高，充填和

39、保压可达良好状态，不须过度增加料管和喷嘴的温度。With proper venting, the injection speed could be increased to achieve good fill and pack conditions, without having to raise the barrel and nozzle heats, improperly.排气排气Vent深度(depth) : 1. 0.075 mm易流塑料(easy-flow mat.) 2. 0.125 mm难流塑料(stiffer-flow mat.)3. 深度深到流道末端见毛边为准 (deep e

40、nough to feel flash at runner end)宽度(width) : 和流道同宽(as wide as runner dia.)排气唇部(vent lip): 1.5mm A1抛光(finish)排气通道通大气(vent channel to atmosphere): 1mm深(deep)流道排气流道排气Runner Vents深度(depth): 参照厂商建议 (refer to manufacturers recommendation)宽度(width): 全圆周长(whole perimeter) or 5mm长度(length): 1.5mm A1抛光(finis

41、h)排气通道通大气(vent channel to atmosphere): 1mm深(deep)分模面排气分模面排气Parting Line Vents深度(depth): 参照厂商建议 (refer to manufacturers recommendation)宽度(width): 全圆周长(whole perimeter)长度(length): 1.5mm排气沟(vent groove): 1mm深(deep)顶出销或心型销排气顶出销或心型销排气Ejector and Core Pin Vents冷却系统设计冷却系统设计Cooling System Design模具冷却设计的目的模具冷

42、却设计的目的Purposes of Mold Cooling Design1. 均衡冷却(改良产品品质)Even Cooling (Improve Part Quality)2.有效冷却 (提高生产力)Efficient Cooling (Increase Productivity)薄壳产品不像传统壁厚者一般可以承受较大的因热传不均而产生的残余应力。 为了将收缩弯翘控制在可以接受的程度，均衡的冷却设计变得非常重要。Thin-wall part can not afford as much thermal induced residual stress as the conventional o

43、ne does. An even cooling design becomes very important to control the shrinkage and warpage at an acceptable level.冷却设计冷却设计Cooling Design射出成型周期时间射出成型周期时间Injection Molding Cycle Time充填时间Fill Time开模时间Open Time后充填时间Post-fill Time对冰箱水果蔬菜盘之类的大零件而言，材料往往占成本50%以上。 对小而薄的零件而言， 成形机费用可占成本的90% ，材料6% ，而模具只占4%。 小而

44、薄的产品较之厚者更能从冷却的改善而获得效益。For larger molded parts, material typically represents more than 50% of the part cost for a refrigerator crisper tray. In the case of a thin-wall small part, the press cost could be 90% of the cost of the part; material constitutes 6% and the mold only 4% of the cost of each pa

45、rt. Small thin-wall parts typically benefit from improved cooling more than thick parts.冷却设计冷却设计Cooling Design典型的冷却系统典型的冷却系统Typical Cooling System模温调节机Temperature controlling unit软管Hoses冷却回路 2Cooling Circuit 2冷却回路 1Cooling Circuit 1泵Pump收集歧管Collection manifold供给歧管Supply manifold模具冷却管路模具冷却管路 Mold Sch

46、ematic冷却孔道冷却孔道Cooling Channels入口Inlet出口Outlet入口Inlet出口Outlet喷泉管喷泉管Bubbler障板管障板管Baffle热管热管Heat Pipe蒸发部位热输入Heat In凝结部位热输出Heat Out液体Liquid蒸汽Vapor灯心 ( 毛细管 )Wick ( Capillary )热管的应用热管的应用The Application Of Heat Pipe理论上最短冷却时间理论上最短冷却时间Min. Possible Cooling Time理论上最短冷却时间the min. possible cooling time产品最大厚度the max. part thickness熔胶的热扩散度thermal diffusivity of the melt射出温injection temp.冷却液温度coolant temp.顶出温度ejection temp.冷却时间和厚度分布冷却时间和厚度分布Cooling Time and Thickness Profile差的设计Bad Design好的设计Good Design冷却孔道直径、深度和节距建议值冷却孔道直径、深度和节距建议值Recommended Diameter, Depth & PitchD : 直径为10至14mm Diam