900410新讲义.ppt

塑膠產品與模具設計Plastic Part and Mold Design徐昌煜Charles Hsu歐磊科技股份有限公司OLE Technology Corp.,模具設計的優先順序Priorities of Mold Design,澆注系統設計(Filling System Design)排氣系統設計(Venting System Design)冷卻系統設計(Cooling System Design)脫模系統設計(Ejecting System Design),澆注系統設計Filling System Design,徐昌煜Charles Hsu,典型的澆注系統Typical Filling System,澆注系統設計的優先順序Priorities of Filling System Design,產品設計(Part Design)型腔設計(Cavity Design)澆口設計(Gate Design)流道設計(Runner Design)豎澆道設計(Sprue Design)噴嘴設計(Nozzle Design),壁厚不均是注塑成形中最大的麻煩製造者。這對薄壁零件尤然。這些麻煩包括了遲滯現象、短射、凹陷、發赤、噴流、翹曲及長冷卻時間等；目前都可用CAE以直接或間接的方式預測。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 CAE.,壁厚不均Non-uniform Wall Thickness,壁厚設計Wall Thickness Design,掏空設計(1)Coring Out Design(1),掏空設計(2)Coring Out Design(2),空洞或/和凹陷的形成Void or/and Sink Mark Forming,肋厚和內圓角半徑的影響The Effect of Rib Thickness&Fillet Radius,肋的底部厚度Bottom Thickness of Rib,肋的設計(一)Rib Design(1),肋的設計(二)Rib Design(2),肋的設計(三)Rib Design(3),與側壁相連之凸轂(熱塑性塑膠)Boss at Wall(Thermoplastics),遠離側壁之凸轂(熱塑性塑膠)Boss Away From Wall(Thermoplastics),外側凸轂Outside Boss,Where 1/r:樑的曲率 curvature of the beamM:彎曲力矩 bending momentE:彈性模數 modulus of elasticityI:斷面積對中立軸的慣性矩 moment of inertia of the cross-sectional area with respect to the neutral axisEI:撓曲剛性 flexural rigidity,撓曲剛性Flexural Rigidity,平板和肋板的比較Comparison between Plain&Ribbed Plates,和平板比，若基於相同的慣性矩(剛性)，肋板需料少了43%，I/A卻增加了1.79倍。肋板的最大厚度減為平板的1/4，使得冷卻時間驟降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 plate is only 1/4 of plain plates;showing a dramatic cooling time reduction of 94%(15/16).,平板和肋板的比較Comparison between Plain&Ribbed Plates,結構設計是薄殼成形零件的基礎。Structural design is the base of thin-wall molding parts.薄殼成形零件不僅僅是一趨勢，而且也是降低成本和提高競爭力的有效途徑。Thin-wall molding part is not only a trend but also an effective way to achieve cost reduction and competitiveness increase.,結構設計和薄殼成形零件Structural Design&Thin-wall Molding Parts,每增加一個澆口，至少增加一條熔接線，同時增加一個澆口痕跡、增加流道的體積以及增加較多的積風。Every time one gate is added,one weld line,at least,one gate mark,more runner volume and more air traps will be added.在型腔能夠完滿充填的前提下，澆口數目是愈少愈好。As long as the cavity is able to be filled appropriately,gates are the less the better.為了減少澆口數目，每一澆口應就塑流力所能及的流長/壁厚比之內，找出可以涵蓋最大零件面積的進澆位置。In order to reduce the number 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.,澆口數目The Number of Gates,熔膠波前推進Melt-Front Advancement,充填模式,積風和熔接線Filling Patterns,Air-Traps and Weld Lines Location,熔接線Weld Lines,材料 Material:PC-GF50,原設計 Original,更改設計 Revised,更改澆口位置以重新定位熔接線Weld Lines Can Be Relocated By Changing Gate Location,典型對頭熔接線伸張強度保留值Typical Butt Weld Tensile Strength Retention Values,熔接線冷料井Weld Slug Well,對頭熔接線 Butt weld,熔接線冷料井Weld slug well,積風Air Traps,排氣Vent,大部份熱塑性塑膠Most ThermoplasticsA 0.08 mmB 3.18 mmC 12.7 mmD 0.25 mm,耐隆和聚縮醛(POM)Nylon and Acetal(POM)A 0.04 mmB 3.18 mmC 12.7 mmD 0.25 mm,進料流道Feed Runner,塑膠成品Plastic Part,A,D,排氣孔Vent,B,SEC.A-A,C,A,A,充填均衡Flow Balance,熔膠波前於同一時間抵達型腔各末端。Melt front reaches the ends of cavity at the same time.,洗衣機圈板,洗衣機圈板,原始設計Original Design,十二澆口設計12 Gate Design,電子零件置物箱材料 Material：ABS,四澆口設計4 Gate Design,電子零件置物箱四澆口和十二澆口設計比較表,如何快速平衡眾多模穴之流道How to Balance Flow In A Multi-cavity Mold,一排支流道之不平衡充填Unbalanced Flow In A Branch,一排支流道平衡後之充填Balanced Flow In A Branch,全模具(128模穴)之不平衡充填Unbalanced Flow In A Mold,全模具(128模穴)平衡後之充填Balanced Flow In A Mold,The melt fills the inside cavities before filling the outside cavities.,The runner system shows that warmer,low-viscosity material(yellow and red)follows the inside wall when the melt splits at an intersection.,剪切速率Shear Rate,剪 切 應 力shear Stress黏 度viscosity剪 切 速 率shear rate,剪切應力Shear Stress,澆口種類Gate Types,導致平直零件的澆口設計Gate Design for Flat Part,中心澆口Center Gate,扇形澆口Fan Gate,最壞的Worst,壞的Worse,較好的Better,最好的Best,側澆口Edge Gate,薄模澆口Film Gate,澆口設計(減少滯流效應)Gate Design to Avoid Hesitation,0.94秒時，遲滯現象在1.2mm厚凸片處發生,公稱厚度3.2mm,幫浦零件(Part,Pump)塑料(Polymer):POM,沒有遲滯現象,幫浦零件(Part,Pump)塑料(Polymer):POM,澆口設計(避免凹陷和空洞)Gate Design to Avoid Sink Mark&Void,使用重疊澆口以避免噴流Avoid Jetting by Using Overlap Gate,正確的澆口位置以避免噴流Avoid Jetting by Locating Gate Correctly,使用凸片澆口以避免噴流Avoid Jetting by Using Tab Gate,使用適當的澆口形狀以避免噴流Avoid Jetting by Profiling Gate Properly,幫浦零件(Part,Pump)塑料(Polymer):POM進澆處(Polymer entrance)：澆口厚(Gate thickness)1.2mm，模穴厚(Cavity thickness)3.2mm問題(Problem)：噴流(Jetting),Poor Design Causing Jetting,Gate,氣輔成型冰箱把手,閥澆口Valve Gate,1.閥澆口梢 Valve-Gate Pin2.加熱管 Heater3.O型環#610 0 Ring4.流道歧管模板 Manifold Plate5.軸封環 Seal Retainer6.套筒軸封 Sleeve Seal7.枕塊 Support Pillar8.油壓缸 Hydraulic Cylinder,閥澆口(一)Valve Gate(1),全部閥澆口同時打開時之充填狀況Mold filling with all the valve gates(shut-off gates)opened at the same time.,閥澆口(二)Valve Gate(2),部份閥澆口延遲打開，改變充填模式Mold filling with delayed valve gate opening;filling pattern,weld lines and air traps are changed.,多澆口設計 Multi-Gate Design,閥式澆口Valve Gate,矩形邊緣澆口設計Rectangular Edge Gate Design,扇形澆口設計Fan Gate Design,L=1.3 mmW=w=澆口寬度 mm gate width in mmA=型腔表面積 mm2 surface area of cavity in mm2n=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 mmt=零件壁厚 wall thick.in mm,h1=n t,h2=wh1/D,重疊式澆口設計Overlap Gate Design,W=w=澆口寬度 mm gate width in mmA=型腔表面積 mm2 surface area of cavity in mm2n=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,L1=0.50.75,L2=h+(w/2),凸耳澆口設計Tab Gate Design,L=0.50.75mmW=w=澆口寬度 mm gate width in mmA=型腔表面積 mm2 surface area of cavity in mm2n=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 t=零件壁厚 wall thick.in mm,h1=n t,h2=0.9 t,L=0.5 0.75 mmd=澆口直徑(mm)gate diameter in mmt=零件壁厚(mm)wall thick.in mmA=型腔表面積(mm2)surface area of cavity in mm2n=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,針點澆口設計Pin Gate Design,d,L,t,潛伏式澆口設計Subgate Design,W=w=澆口寬度 mm gate width in mmA=型腔表面積 mm2 surface area of cavity in mm2n=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=ntt=零件壁厚 wall thick.in mm,水力直徑 Hydraulic Diameter,Where is the hydraulic diameter 水力直徑 A is the cross-sectional area of the flow 流路斷面積 P is the wetted perimeter 濕周長,水力直徑 Hydraulic Diameter,在不同剖面形狀，相同斷面積下之變化Various runner profiles,based on the same cross-sectional area,流道尺寸設計(1)Runner Sizing(1),D:流道直徑(mm)runner diameter in mmW:下游塑膠重量(g)downstream plastic weight L:流道長度(mm)runner length in mm,流道尺寸設計(2)Runner Sizing(2),流道尺寸設計(3)Runner Sizing(3),流道尺寸設計(4)Runner Sizing(4),流道尺寸設計(A1)Runner Sizing(A1),G:重量 weightS:零件厚度 thicknessD:參考直徑 reference diameter,流道尺寸設計(A2)Runner Sizing(A2),G:重量 weightS:零件厚度 thicknessD:參考直徑 reference diameter,流道尺寸設計(B)Runner Sizing(B),D:參考直徑 reference diameterL:長度 lengthfL:長度係數 Length coefficientD:流道直徑 runner diameter,冷料井設計Cold Slug Well Design,倒椎度冷料井豎澆道拉料桿Reverse taper cold slug-well sprue puller,冷料井設計Cold Slug Well Design,澆道襯套尺寸Sprue Bushing Sizing,排氣系統設計Venting System Design,徐昌煜Charles Hsu,為何排氣仍然還是一個問題？Why venting is still a problem?因為降低射速，讓積風有較多的時間逃氣，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.,排氣Vent,射速一降，熔膠溫度很快降低，射壓必須提高，殘餘應力隨之提高，翹曲的可能性增加。如果想藉提高料溫，以降低射壓，料溫必須升得很高，這樣又會引起塑料裂解。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 required injection pressure,the barrel temperature has to be increased to a quite high level and polymer degradation would be induced.,排氣Vent,高料溫和高射壓都說明充填系統有了流動的問題,Both high barrel temperature and high injection pressure are indications of flow problem in the filling system.,排氣Vent,我們常發現:射速提高時，塑料表現得更為出色。It is quite common that material performs better when it is injected faster.最適化螺桿速度充分運用摩擦熱，將塑流保持在最佳狀態。許多充填和翹曲的問題也就迎刃而解。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.,排氣Vent,有了適當的排氣，射速可以提高，充填和保壓可達良好狀態，不須過度增加料管和噴嘴的溫度。,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.,排氣Vent,深度(depth):1.0.075 mm易流塑料(easy-flow mat.)2.0.125 mm難流塑料(stiffer-flow mat.)3.深度深到流道末端見毛邊為準(deep enough to feel flash at runner end)寬度(width):和流道同寬(as wide as runner dia.)排氣唇部(vent lip):1.5mm A1拋光(finish)排氣通道通大氣(vent channel to atmosphere):1mm深(deep),流道排氣Runner Vents,深度(depth):參照廠商建議(refer to manufacturers recommendation)寬度(width):全圓周長(whole perimeter)or 5mm長度(length):1.5mm A1拋光(finish)排氣通道通大氣(vent channel to atmosphere):1mm深(deep),分模面排氣Parting Line Vents,分模面排氣Parting Line Vents,深度(depth):參照廠商建議(refer to manufacturers recommendation)寬度(width):全圓周長(whole perimeter)長度(length):1.5mm排氣溝(vent groove):1mm深(deep),頂出銷或心型銷排氣Ejector and Core Pin Vents,冷卻系統設計Cooling System Design,徐昌煜Charles Hsu,模具冷卻設計的目的Purposes of Mold Cooling Design,1.均衡冷卻(改良產品品質)Even Cooling(Improve Part Quality)2.有效冷卻(提高生產力)Efficient Cooling(Increase Productivity),薄殼產品不像傳統壁厚者一般可以承受較大的因熱傳不均而產生的殘餘應力。為了將收縮彎翹控制在可以接受的程度，均衡的冷卻設計變得非常重要。Thin-wall part can not afford as much thermal induced residual stress as the conventional one does.An even cooling design becomes very important to control the shrinkage and warpage at an acceptable level.,冷卻設計Cooling Design,射出成型週期時間Injection Molding Cycle Time,充填時間Fill Time,開模時間Open Time,後充填時間Post-fill Time,對冰箱蔬果盤之類的大零件而言，材料往往佔成本50%以上。對小而薄的零件而言，成形機費用可佔成本的90%，材料6%，而模具只佔4%。小而薄的產品較之厚者更能從冷卻的改善而獲得效益。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 part.Small thin-wall parts typically benefit from improved cooling more than thick parts.,冷卻設計Cooling Design,典型的冷卻系統Typical Cooling System,模具冷卻管路 Mold Schematic,冷卻孔道Cooling Channels,噴泉管Bubbler,障板管Baffle,熱管Heat Pipe,熱管的應用The Application Of Heat Pipe,理論上最短冷卻時間Min.Possible Cooling Time,理論上最短冷卻時間the min.possible cooling time,產品最大厚度the max.part thickness,熔膠的熱擴散度thermal diffusivity of the melt,射出溫度injection temp.,冷卻液溫度coolant temp.,頂出溫度ejection temp.,冷卻時間和厚度分佈Cooling Time and Thickness Profile,差的設計Bad Design,好的設計Good Design,冷卻孔道直徑、深度和節距建議值Recommended Diameter,Depth&Pitch,D:直徑為10至14mm Diameter of Cooling Channel,10 to 14 mmd:深度為D至3D Depth,D,to 3D P:節距為3D至5D Pitch,3D to 5D,原始設計Original Design,修正設計Revised Design,原始設計Original Design,修正設計Revised Design,原始設計Original Design,修正設計(一)Revised Design(1),修正設計(二)Revised Design(2),不平衡的設計Unbalanced Design,平衡的設計Balanced Design,不用限流孔梢的內歧管設計Internal Manifold Design without Frops,使用限流孔梢的內歧管設計Internal Manifold Design Utilizing Frops,限流孔梢Flow Resistance Orifice Pin,紊流和層流Turbulent and Laminar Flows,紊流Turbulent Flow,層流Laminar Flow,雷諾數Reynolds Number,雷諾數(無因次)Reynolds number(dimensionless),密度density(g/cm3),直徑diameter(cm),速度velocity(cm/sec),黏度viscosity(poise or dyne-sec/cm2 or g/cm-sec),Nu對雷諾數(Re)Nusselt Number Vs.Reynolds Number,差的設計Poor Design,好的設計Better Design,差的設計Poor Design,好的設計Better Design,差的設計Poor Design,好的設計Better Design,冷卻設計原則Cooling Design Principles,選擇熱擴散係數大的塑料。Select Plastic Material with large thermal diffusivity.採用薄而均一的製件厚度。Use a thin and uniform part thickness.在型腔周圍均衡的配置冷卻孔道。Layout cooling channels around cavities evenly.在熱傳的道路上移除空氣間隙和空氣囊。Remove air gaps and pockets from heat transfer path.平衡冷卻液流動。Balance coolant flow.檢查冷卻效率。Check cooling efficiency.促使冷卻勻稱。Make cooling evenly.選擇適當設備。Select appropriate equipment.,