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1、塑膠產品設計Plastic Part Design徐昌煜Charles Hsu就傳統射出成形而言，實用的最小壁厚在0.75到1.00mm 之間。 如果要採用更薄的壁厚，卻又缺乏實際的經驗，可以借助CAE作科學的決定。For conventional injection molding , a practical minimum wall thickness is in the range of 0.75 to 1.00 mm. When thinner walls are required but actual experience is absent, the minimum possibl
2、e thickness can be scientifically determined by CAE.壁厚Wall Thickness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, inclu
3、ding 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設計高收縮率材料成型品時，設計者應將壁厚變化限制在10%。 就低收縮率材料而言， 許容壁厚變化可到25%。While designing injection molded parts in high mold shrinkage factor
4、materials, the designer should try to limit wall thickness variation to 10%. The allowable wall thickness variation for the low mold shrinkage factor materials can be up to 25%.壁厚不均Non-uniform Wall Thickness壁厚設計Wall Thickness Design差 Poor較好 Better最好 Best掏空設計(1) Coring Out Design (1)改進設計 Improved原設計
5、Original差 Poor改進 Improved掏空設計(2) Coring Out Design (2)外側凸轂Outside Boss AAA ( DIA )BB = AB= 2A ( max. )Section A-A熔接線 70 100 熔接線空洞或/和凹陷的形成Void or/and Sink Mark Forming空洞 ( Void )凹陷 ( Sink Mark )肋厚和內圓角半徑的影響The Effect of Rib Thickness & Fillet Radius突出件和公稱厚壁相交處的內圓角半徑太大，會致使凹陷、空洞、殘餘應力和長的冷卻時間。 該內圓角半徑太小，會致
6、使應力集中。 一個好的折中方案是採用公稱壁厚的25% ，作為內圓角半徑。A large fillet radius causes sink mark, void, residual stress and long cooling time. A small fillet radius causes stress concentration. A good compromise is to use a radius, which is 25% of the nominal wall (NW), at the junction of the NW and a projection.內圓角半徑 Fi
7、llet Radius肋的底部厚度Bottom Thickness of RibW0.5W2.5WW1.2WD1.5WD(A)(B)肋的設計 (一 )Rib Design ( 1 )t = wall thichnessB = 0.5tC = 3 tAAD = 2 BE = 0.13 mm(radius)F = 1.5 - 2 deg假如需要更大的強度,可增加肋的數目If more strength is required, add additional ribs.FBDECt 肋的設計 (二 )Rib Design ( 2 )角板設計 (三 )Gusset Design ( 3 )與側壁相連之
8、凸轂(熱塑性塑膠)Boss at Wall ( Thermoplastics )A =凸轂附著處壁厚 wall thicknessB =凸轂外環直徑 dia. of boss over radiiC = 0.5 AD = 2 BE = 1 2 degF = 0.13 mm ( radius )G = DH = 0.8 AI = A / 4J = 2 BK = 0.3 1 JL = 0.5 A LHAAKEIGJDAFCBSection A-A遠離側壁之凸轂(熱塑性塑膠)Boss Away From Wall( Thermoplastics ) A =凸轂附著處壁厚 wall thickness
9、B =凸轂外環直徑 (含底部修整圓弧半徑) dia. of boss over radiiC = 0.5 AD = 2 BE = 1 - 2 degF = 0.13 mm ( radius )G = 0.95 DH = 0.3 G min. to G max.I = 0.5 AHEFDFGCBAIWall Thickness, RibConventional0.080 to 0.125 in(2.0 to 3.2 mm)Thinwall:0.050 to 0.080 in 0.050 in(1.2 to 2.0 mm)(1.2 mm)Wall Thickness, BossesConventi
10、onal0.080 to 0.125 in(2.0 to 3.2 mm)Thinwall:0.050 to 0.080 in 0.050 in(1.2 to 2.0 mm)(1.2 mm)Wall Thickness, GussetsConventional0.080 to 0.125 in(2.0 to 3.2 mm)Thinwall:0.050 to 0.080 in 0.050 in(1.2 to 2.0 mm)(1.2 mm)突出件在和公稱厚壁相交處的建議厚度：以高縮水率的結晶性塑膠而言，可採用公稱壁厚的50% 。 以低縮水率的非結晶性塑膠而言，可採用公稱壁厚的75% 。The rec
11、ommended thickness at the junction of a projection and the nominal wall (NW) is 50% of the NW thickness for high-mold-shrinkage, crystalline materials. The lower-mold-shrinkage-factor, amorphous plastics can have thicknesses of up to 75% of the parts NW thickness . 突出件壁厚Thickness of the Projection有些
12、情形，在美觀的考慮下，是不容許些微凹陷的。 設計者應當考慮將建議厚度減少10%。In those cases where aesthetic considerations preclude even a slight sink mark, a designer should consider reducing the recommended rib thickness by an additional 10 percent .突出件壁厚Thickness of the Projection從成型容易的觀點來看，突出件的高度以產品公稱壁厚的2.5到3倍為宜。From an ease of mol
13、ding perspective, the height of projections should be limited to 2.5 to 3 times the part nominal wall thickness.突出件高度 Height of the Projection強固的、脆的、剝蝕性的、黏的塑件要有大的脫模角和光滑的拋光。 軟的、延展性的、和光滑的塑件則可有小的脫模角。Large draft angles and a smooth polish are required for parts molded in strong, brittle, abrasive, and s
14、ticky materials. Smaller draft angles can be used on soft, ductile, and slippery materials.突出件脫模角 Draft Angle of the Projection以成本和可製造性的觀點，理想的脫模角是消費者可以接受的前題下，最大的角度。 就多數情況而言，每邊1應已足夠，但2 或 5 可以更好。 模穴應順著開模方向打光。The ideal draft angle, from a cost and manufacturability perspective, is the largest angle tha
15、t will not distract from the consumers acceptance of the product. In most cases, 1 per side will be adequate, but 2 or 5 per side would be better. The cavities that form projections should be draw-polished.突出件脫模角 Draft Angle of the Projection距離應大於產品公稱壁厚的2倍。 使得模具鋼材具備足夠的強度以抵抗彎曲，並且提供足夠的吸熱器，以免產生凹陷和成型應力。
16、This distance should be at least 2 times the parts nominal wall thickness, so the mold steel provide enough strength to resist bending and enough heat sink to avoid sink mark and molded in stress.突出件和側壁/突出件的距離 The Distance between Projection and Side Wall/ProjectionAAAAA - AA - ALong RibAir TrapWher
17、e 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 RigidityW樑 BeamLWhere : 最大偏移 maximum deflection W : 負荷 load L : 樑長 length of be
18、am E : 彈性模數 modulus of elasticity I : 斷面積對中立軸的慣性矩 moment of inertia of the cross- sectional area with respect to the neutral axis EI : 撓曲剛性 flexural rigidity: 最大應力 maximum stress: 中立軸到到其斷面離其最遠的點的距離 distance from the extreme point of a cross section to the neutral axis of this cross section Youngs Mo
19、dulus, EThe ratio between stress and strain is constant, obeying Hookes Law, within the elasticity range of any material. This ratio is called Youngs modulus and is measured in Mpa or psi.Neutral Axis?10.8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
20、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
21、板和肋板的比較Comparison between Plain & Ribbed PlatesRib height/base thicknessRib spacing ratio (Wr=.33,.2,.1,.05,.02,.01)Stressratio應力比 (肋/無肋)Stress Ratio (Ribbed/Unribbed)Deflection ratioRib spacing ratio(Wr=.33,.2,.1,.05,.02,.01)Rib height/base thickness偏移比 (肋/無肋)Deflection Ratio (Ribbed/Unribbed)各種一體成
22、形的內鎖件能增加薄殼的剛性。A variety of molded-ininterlocks can add stiffness to thin-wall housing designs.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 c
23、ompetitiveness increase.結構設計和薄殼成形零件Structural Design & Thin-wall Molding PartsLiving Hinge Design for PP and PE: (a) before, and (b) after Bending 180Typical Values of Living Hinge Design for PP and PE: (a) Most Application; (b) Self-opening Hinge DesignMost Common Living Hinge Design: (a) before, a
24、nd (b) after Bending 180Recommended Living Hinge Design with the Neutral Axis in the Center: (a) before, and (b) at Bending Angle of 180Cross Section through the Entire Hinge Showing Its Principal DimensionsCross Section of a Portion of a Living Hinge Design and Its Neutral Axis PositionHinge Design
25、 Detail: (a) as Molded; (b) as Assembled“Right Way”Assembly Hinge DetailCable Ignition Bracket Axonometric ViewCable Ignition Bracket Side ViewCable Ignition Bracket Top ViewHinge Detail:(a) Initial Design;(b) Improved DesignHinge Behavior after AssemblyPOLYPROPYLENE HINGE DESIGNFULL R.0.18 - 0.300.
26、25 R.(2) PLXY0.25 TEAR RIB AT EACH END OF HINGENOTES:1. Y DIM. PER PART DESIGN2. X DIM. = 2Y + 0.250.76 R.0.25 R.1.250.76 R.(2) PL100O0.130.18 0.300.25 TEAR RIBAT EACH END OF HINGEPOLYPROPYLENE HINGE DESIGN孔 Holes以射出成型而言，圓孔形狀理想，原因是塑料冷卻時， 它收縮到心型銷，若銷為圓形，應力會均勻的分布在圓銷面上。Round holes are the ideal shape fo
27、r the injection molding process. The reason for this is that as plastic material cools it shrinks onto the core pin that forms a hole and, with round holes, the stress is uniformly distributed around it.孔 Holes這一尼龍風扇因安裝孔的直線孔緣末端的鎖入應力而損毀。This nylon fan failed due to molded-in stress at the end of the
28、straight section on the mounting hole.孔 Holes孔 Holes最初，此一玻纖補強的尼龍計時鏈輪中央的方型驅動軸孔，有四個銳角。 使用幾個月後，這些鏈輪，從方孔的銳角，到其附近的鏈輪齒根，產生裂隙而報廢。 後來，在方孔的四個角落，加了向外延伸的小孔之後，鏈輪便不再開裂。The glass-fiber-reinforced nylon timing sprockets were introduced with sharp corners on the square drive shaft hole. These sprockets failed after
29、 several months in the field due to cracks radiating from a corner on the square hole to the root of a nearby gear tooth. These field failures were eliminated by adding the outwardly extending radiuses.孔 Holes內圓角和向外延伸的內圓角(B, C, D)可以減低鎖入的應力並且使得產品變強。Inside and outwardly extending radiuses (B, C, D) re
30、duce molded-in stress and result in a stronger part.孔 Holes孔A和B能以簡單直接開模的方式成形，孔C則須要一較複雜的側向運動心型，方能成形。Holes A and B can be molded with a simple, straight opening mold. Hole C requires a more complex side-acting mold.從易於成型的觀點來看，相鄰二孔緣的距離， 或是孔緣和產品邊緣的距離， 至少要有壁厚的兩倍， 而絕對不可小於壁厚。From an ease of molding perspec
31、tive, the distance from one hole to the next , or to the edge of a part, must be at a minimum two times the parts wall thickness, and never less than the parts wall thickness孔 Holes孔 Holes圖中的孔太靠近產品的邊緣，塑料的收縮使得該孔和其周圍的薄壁都因之扭曲。The hole shown here is too close to the edge of the part. Shrinkage of the pl
32、astic material has distorted this hole and the thin wall around it.孔 Holes(Figure I)孔 Holes圖I的盲孔A的長徑比應以2:1或3:1為限。 形成圖I穿孔B的心型銷的自由端是頂在母模面上。 這樣的心型銷獲得支持，而長徑比可增加到6:1 。The length-to-diameter ratio of the blind hole in Figure I(A) is limited to only 2:1 or 3:1. The through hole B in Figure I allows the fre
33、e end of the core pin to be seated against the cavity. This supports the core and allows its length-to-diameter to be 6:1.孔 Holes如圖I的C所示，將型心延伸至母模側的配合孔，可以提供額外的支撐，兩頭支撐的型心銷的長徑比可達12:1。 如圖I的D所示，以二支型心銷成型深孔，可以消除型心銷和母模面的磨耗。 這種方法產生的孔也可有12:1的長徑比。Telescoping the core into a mating hole in the cavity, C in Figu
34、re I, provides additional support. A core pin anchored at both ends can have a length-to-diameter ratio of 12:1. Molding a deep hole with two core pins, D in Figure I, eliminates wear between the core pin and the cavity. Holes produced in this manner can also have a 12:1 length-to-diameter ratio.塑膠工
35、業協會(SPI)指定12種拋光，從鑽石高度拋光，到噴砂粗度拋光。 依照SPI模具拋光指南，來指定表面光滑度，已經被國際接受。The Society of the Plastics Industry (SPI) specified 12 finishes, ranging from a high diamond polish to a rough, blasted surface. The SPI Mold Finish Guide has become the internationally accepted for specifying surface finishes. 表面光滑度Surf
36、ace Finish如果型心形成的內面沒有拋光，頂出力和循環時間都會相應增加。If the core that forms the inside surfaces is not smoothly polished, the ejection forces and the cycle time will increase accordingly. 表面光滑度Surface Finish只在成型品頂出方向拋光，可以消除側凹。 這種拋光方法被稱作“抽拋” 。 設計工程師應於零件須要最小或0脫模角時，指定抽拋。Polishing the mold only in the direction that
37、the molded part moves during ejection eliminates these undercuts. This polishing technique is called “draw polishing.” Design engineers would be well advised to specify draw polishing on parts requiring minimal or no draft angles. 表面光滑度Surface Finish無論模面如何光滑，低密度聚乙烯都無法產生和聚苯乙烯接近的光亮外表。 補強料加得多的塑料不能有效的產生
38、光亮的外表。 一般說來，熱模較之冷模，較能產生光滑的外表。 保壓不足的產品無法忠實的複現模面的光滑。Regardless of the finish on the mold, low-density polyethylene can never produce the shiny appearance of a polystyrene part. Heavily filled or reinforced polymer cannot reliably produce shiny surfaces. Generally speaking, a hot mold will produce bett
39、er surfaces than a cold mold. A poorly packed out part will not faithfully replicate the mold polish on all of the part surfaces. 表面光滑度Surface Finish最軟的聚乙烯和聚氯乙烯、 polyurethanes 和某些熱塑性elastomers 有沾黏高度拋光金屬面的傾向。 這類黏的材料，一般較易從粗糙面或輕度噴砂面脫模。The softest polyethylenes and polyvinyl chlorides, polyurethanes, an
40、d some thermoplastic elastomers have a tendency to adhere to highly polished metal surfaces. Sticky materials of this type will normally release better from molding surfaces with matte or lightly blasted surface finish. 表面光滑度Surface Finish強壯而又有些彈性的塑膠，像聚丙烯、ABS和耐衝擊聚苯乙烯，較之剛而脆的材料， 如一般用途用聚丙烯和壓克力，更能接受粗略拋光
41、的模面。 對這些硬而脆的材料，抽拋是非常有益的 。Strong but somewhat flexible plastics, such as polypropylene, ABS, and impact styrene, are more tolerant of roughly polished molding surfaces than rigid, brittle materials, such as general-purpose styrene and acrylics. Draw polishing is very beneficial with these hard, britt
42、le materials. 表面光滑度Surface Finish不能指望產品設計師、模具製造者以及拋光公司知道所有不同塑料的癖性。然而，我們可以倚賴塑料供應商和有經驗的成型者， 他們知道那一種模面光滑度適合那一種特定的塑料。Product designers, moldmakers, and polishing companies cannot be expected to know the idiosyncrasies of all of the different plastic materials. Plastic material suppliers and experienced
43、molders can, however, be relied upon to know what mold finish is optimal for a given material. 表面光滑度Surface Finish有些工業界的內行者 ， 估計拋光代表了模具平均成本的10% 。 這個平均值當然會有明顯的差異，這要看模具的尺寸和形狀、金屬的硬度、 要求拋光的程度、 以及拋光前模面的光滑程度。Some industry insiders have estimated that, on the average, polishing can represent 10% of a mold
44、overall cost. This average will obviously vary, depending on the size and shape of the mold, the hardness of the metal, the level of polish required, and how well the mold was finished prior to polishing.表面光滑度Surface Finish對不透明件而言，大多數消費者無法分辨SPI指南中最高三級光滑度的分別 ， SPI的最高二級光滑度應為可以看穿的透明件保留。 換言之，為何要花錢在消費者無法
45、感激的表面光滑度上？Most consumers will not notice the differences between the SPI Guide three highest finishes on an opaque part. The two best SPI finishes should be reserved for transparent, see-through parts. In other words, why spend money on a surface finish that the consumer cannot appreciate ? 表面光滑度Sur
46、face Finish產品圖上必須標明表面光滑度，高度建議參照SPI模具光滑度指南。The surface finish must be clearly indicated on the part drawing. It is strongly recommended that surface finish be specified according to SPI Mold Finish Guide.表面光滑度Surface Finish一般說來，成本或交貨期，會隨著決定採用電火花加工法、噴砂法和照相化學腐蝕法的順序而增加。 所有方法都能供給不同程度的表面花紋。 較細的花紋像編織物或風乾木材
47、的紋理，只能靠照相化學腐蝕提供。Generally speaking, the cost and delivery time increases with the decision to go from EDMing to blasting to PCEing. All three techniques can provide varying degrees of matte finishes. The more detailed finishes, such as fabric or weathered wood, are available only with PCEing. Note:
48、PCE is Photo Chemical Etching表面花紋Pattern根據經驗法則，對母模側模壁(冷卻時，塑料從其離開)而言，每0.025mm咬花深度， 單邊至少要有1.5 脫模角。 有些咬花供應商要求在公模側模壁(冷卻時，塑料向其包裹) ，提供2倍的脫模角。 安全的作法是避免在内面採用咬花。The rule of thumb, applied to the side wall of cavities that the material shrinks away from as it cools, is a minimum of 1.5 of draft per side for e
49、ach 0.025mm (0.001 inch) of texture depth. Some texture suppliers ask for twice as much draft on inside surfaces, that the material shrinks onto as it cools. A safer approach is to avoid using texture on inside surfaces.咬花Texture設計者必須指出咬花從那裏開始，到那裏結束。 一個好的咬花標註，應該指出花紋號碼 、咬花深度、 咬花位置，如果要更得當的話，還要加上花紋的方向。
50、 當一產品是由數件零件組合而成，一定要指出咬花花紋的方向。The designer must indicate where the texture stops and starts. A good texturing note should indicate the pattern number, depth of texture, its location, and - if appropriate - the direction of the pattern. In those instances where several parts fit together in one produc
51、t, the direction of the texture pattern absolutely must be specified.咬花Texture設計者完成產品設計之前，能做的最重要的單一事項，就是會同專業的咬花供應商作專案檢討。The single most important thing that a designer can do to optimize the use of texturing is to review the project with a knowledgeable texture supplier before finalizing the part de
52、sign.咬花Texture半結晶塑料的收縮率較高，這些塑料因在平行和垂直於熔膠流動方向有著不同的收縮率，而多了一層問題。 這問題又因成型條件改變致使結晶度變化而更形複雜。 如果塑料冷卻得慢，結晶度和收縮率都會增加。The semi-crystalline plastics has higher mold shrinkage factors. These materials have the additional problem of different shrinkage factors parallel to and perpendicular to the direction of me
53、lt flow. This problem is further compounded by variations in the degree of crystallinity caused by changes in molding conditions. If the material is cooled slowly, there will be an increase in crystallinity and mold shrinkage.收縮Shrinkage 非結晶塑料收縮率低，較易維持尺寸的複現性。 發表的收縮率， 是以3.175mm (0.125吋)的壁厚為準。It is ea
54、sier to maintain dimensional reproducibility with low mold shrinkage factor amorphous materials.The published mold shrinkage data is based on a molded part with a 3.175mm (0.125inch) wall thickness.收縮Shrinkage 設計射出成型零件，當塑料收縮率高時，應試圖限制壁厚變化在10%之內 。 當塑料收縮率低時， 許容壁厚變化在25%以內。While designing injection molde
55、d parts in high mold shrinkage factor materials, the designer should try to limit wall thickness variations to 10%. The allowable wall thickness variation for the low mold shrinkage factor materials can be up to 25%.收縮Shrinkage 塑膠模具設計Plastic Mould Design徐昌煜Charles Hsu模具設計的優先順序Priorities of Mould Des
56、ign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 (Spru
57、e Design)噴嘴設計 (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典型的澆注系統Typical Filling System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
58、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
59、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
60、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熔接線Weld Lines熔接線Weld Lines當波前相遇後，繼續一塊兒流動，如此產生的熔接線是動態的。 這樣的線條也稱作熔合線。 熔接線形成後，熔膠不再流動，如此產生的熔接線是靜態的或是對頭的。 靜態的熔接線位於型腔的末端， 一般比靠近澆口的動態的熔接線脆弱而且明顯。When the flow fronts meet and continue to flow together, the resulting weld
61、line is referred to as dynamic. This type of weldline is also called a meldline. Weldlines that are formed with no additional melt flow are referred to as static or butt weldlines. Static weldlines located at the extremities of a cavity are normally weaker and more obvious than dynamic weldlines for
62、med close to a gate.左邊澆口在這些窗葉的中央，產生了靜態的熔接線。The gate located on the left side creates static weldlines in the middle of these louvers.熔接線Weld Lines熔接線Weld Lines這一部分充填的產品，顯示了兩條靜態的熔接線，在外面二孔外產生； 澆口位於產品上邊中央。This partially filled part shows two static weldlines by the outside holes. The gate is located at
63、 the center of the part, near the top.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尼隆和聚縮醛 ( 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 PartAD排氣槽VentBSEC. A-ACAA流動平衡Flow Balance熔膠波前於同一時間抵達型腔各末端。Melt front reaches the
64、 ends of cavity at the same time.洗衣機圈板洗衣機圈板冷氣通風飾罩-原始設計Air-conditioner Grille, Original18 gatespressure: 76 MPa冷氣通風飾罩-更正設計Air-conditioner Grille, Revised8 gatespressure: 75 MPa分析結果比較 Comparison of Analysis Results十二澆口設計12 Gate Design原始設計Original Design電子零件置物箱材料 Material：ABS四澆口設計4 Gate Design更正設計Revis
65、ed Design電子零件置物箱材料 Material：ABS電子零件置物箱四澆口和十二澆口設計比較表 論語季氏第十六 不患寡而患不均， 不患貧而患不安。 - - 孔子 - -如何快速平衡多型腔模之塑流How to Balance Flows In A Multi-cavity Mould首先調整一排支流道內之次支流道尺寸，使此支流道內之各型腔可平衡充填。First, adjust runner size in one branch to make flow balanced in this branch.再調整各支流道前段之尺寸，使各支流道可平衡充填。Then, adjust the fir
66、st sections runner size in each branch to make flow balanced in all branches.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 Branch128型腔模之不平衡充填Unbalanced Flow In A 128 Cavity Mould128型腔模平衡後之充填Balanced Flow In A 128 Cavity MouldThe runner system shows that warmer, low-viscosity m
67、aterial (yellow and red) follows the inside wall when the melt splits at an intersection.Melt ” Flipper ” 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針點澆口Pin Gate扇型澆口Fan Gate潛伏澆口Submarine Gate邊緣(薄膜)澆口Edge ( Film ) Gate凸片澆口Tab Gate閥式澆口Valve Gate環狀澆口Ring
68、 Gate導致平直製件的澆口設計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澆口gate薄thin厚thick差的設計Poor好的設計Good薄thin厚thick澆口gate0.94秒時，遲滯現象在1.2mm厚凸片處發生幫浦零件(Part, Pump)塑料(Polymer): POM公稱厚度3.2mm沒有遲滯現象幫浦零件(Part, Pu
69、mp)塑料(Polymer): POM澆口設計(避免凹陷和空洞)Gate Design to AvoidSink Mark & Void澆口gate澆口gate差的Poor好的Good噴流 Jetting使用沖擊型澆口以避免噴流Avoid Jetting by Using Impingement Gate差的Poor好的Good差的Poor好的Good使用沖擊型澆口以避免噴流Avoid Jetting by Using Impingement Gate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
70、 Profiling Gate Properly差的Poor好的Good幫浦零件(Part, Pump)塑料(Polymer): POM進澆處(Polymer entrance)：澆口厚(Gate thickness) 1.2mm，型腔厚(Cavity thickness) 3.2mm問題 (Problem)： 噴流(Jetting)Poor Design Causing JettingGatePart : Handle, RefrigeratorMaterial : ABSProblem : Jetting Mark Gas Pin氣輔射出成型冰箱把手澆口及氣針入口澆口太小,導致噴流痕產生厚
71、度差異過大,導致二次噴流痕產生R角過小,氣體通路接近把手內側,外側則因體積收縮造成凹陷痕跡閥式澆口Valve Gate1. 閥式澆口梢 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閥式澆口 (一)Valve Gate ( 1 )全部閥式澆口同時打開時之充填狀況Mold filling with all the valve gates (
72、 shut-off gates ) opened at the same time.閥式澆口 (二)Valve Gate ( 2 )部份閥式澆口延遲打開，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 DesignL = 0.5 0.75 mmW = 澆口寬度 ( mm ) gate width in
73、 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, PP 0.75 for ABS 0.8 for CA, PMMA, PA , PC 0.9 for PVCh = n th = 澆口厚度( gate thick. in mm )t = 製件壁厚( wall thick. in mm )WtLh扇形澆口設計Fan Gate DesignL= 1.3mmW= w= 澆口寬度 mm gate width in mmA= 型腔表面積 mm su
74、rface area of cavity in mmn= 材料常數 material constant 0.6 for PE, PS 0.7 for POM, PP 0.75 for ABS 0.8 for CA, PMMA, PA , PC 0.9 for PVC澆口厚度 gate thick. in mmt= 製件壁厚 wall thick. in mm 22 h1 = n t h2 = wh1/D重疊式澆口設計Overlap Gate DesignW= w= 澆口寬度 mm gate width in mmA= 型腔表面積 mm surface area of cavity in mmn
75、= 材料常數 material constant 0.6 for PE, PS 0.7 for POM, PP 0.75 for ABS 0.8 for CA, PMMA, PA , PC 0.9 for PVC澆口厚度 gate thick. in mm = nt澆口長度 land length in mm t= 製件壁厚 wall thick. in mm 22 L1 = 0.50.75L2 = h+( w/2 )凸耳澆口設計Tab Gate DesignL= 0.50.75mmW= w= 澆口寬度 mm gate width in mmA= 型腔表面積 mm surface area o
76、f cavity in mmn= 材料常數 material constant 0.6 for PE, PS 0.7 for POM, PP 0.75 for ABS 0.8 for CA, PMMA, PA , PC 0.9 for PVC澆口厚度 gate thick. in mm t= 製件壁厚 wall thick. in mm 2 2h1 = n th2 = 0.9 t針點澆口設計Pin Gate DesignL = 0.5 0.75 mmd = 澆口直徑( mm ) gate diameter in mmt = 製件壁厚( mm ) wall thick. in mmA = 型腔表
77、面積 ( mm ) surface area of cavity in mmn = 材料常數 material constant 0.6 for PE, PS 0.7 for POM, PP 0.75 for ABS 0.8 for CA, PMMA, PA , PC 0.9 for PVCdLt潛伏式澆口設計Subgate 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, PP 0.7
78、5 for ABS 0.8 for CA, PMMA, PA , PC 0.9 for PVC澆口厚度 gate thick. in mm = ntt= 製件壁厚 wall thick. in mm 230 15 252水力直徑 Hydraulic DiameterWhere 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 濕周長在不同剖面形狀，相同斷面積下之變化Various runner profiles, based on th
79、e same cross-sectional area水力直徑 Hydraulic Diameter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)H/2 (L)比較圓形流道截面積(AR)與改良型梯形流
80、道截面積(AT)。假設圓形流道的直徑與改良型梯形流道的高度相等。Comparing the cross-sectional area of full-round runner(AR) and the one of modified trapezoidal (AT),when the diameter of the round runner and the height of the trapezoidal runner are the same. 換言之，改良型梯形流道所使用的材料比圓形流道的材料多了20.38%。In other words，modified trapezoidal runn
81、er uses 20.38% more material than full-round runner does.冷料井設計Cold Slug Well Design2d次流道Secondary runnerd主流道Primary runner澆口Gate型腔Cavity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 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 sp
82、rue puller冷料井設計Cold Slug Well Design澆道襯套尺寸Sprue Bushing Sizing噴嘴球頭和澆道襯套承窩半徑 Radius of Nozzle Head & of Sprue Bush Socket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 gi
83、ve 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
84、 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
85、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,
86、 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
87、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 Vent流道排氣Runner Vent深度(depth) : 參照廠商建議 (refer to manufactu
88、rers recommendation)寬度(width) : 全圓周長(whole perimeter) or 5mm/25mm長度(length) : 1.5mm or 1mm 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 Vent分模面排氣Parting Line VentMaterial: PC-GF深度(depth) : 參照廠商建議 (refer to manufacturers recommendation)寬度(width) : 全圓周長(whole perimeter)
89、長度(length) : 1.5mm排氣溝(vent groove): 1mm深(deep)頂出銷或心型銷排氣Ejector or Core Pin VentVENTING GUIDELINES FOR FULLY OPTIMIZED MOLDS POLYMERDEPTH OF VENT (mm)EASY FLOWSTIFF FLOW GLASS FILLEDABS, SAN, HIPS0.05080.0762Acetal0.01270.0381Acrylic0.05080.0762Cellulose/Acetate/Butyrate0.02540.0381Nylon 6/60.0127Nyl
90、on 6/6 13% Glass0.01270.0381Polyallomers0.01270.0254Polycarbonate0.03810.0762Polyethylene0.02540.0508Polypropylene0.02540.0508Polyphenylene Oxide0.02540.0762Polyphenylene Sulfide0.0127Polysulfone0.0254Crystal Polystyrene0.02540.0508Polyvinylchloride (Rigid)0.02540.0762Polyvinylchloride (Plasticized)
91、0.02540.0508多孔鋼提供有效的排氣，使得充填快速，射壓降低。 多孔鋼有助於高速成型薄殼件和微成型件。The efficient venting provided by porous steel allows cavities to be filled faster and at lower pressure. Porous steel may be very helpful in the high-speed molding now being used for thin-wall and micromolded parts.排氣Vent冷卻系統設計Cooling System De
92、sign徐 昌 煜Charles Hsu模具冷卻設計的目的Purposes of Mould Cooling Design1. 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 stre
93、ss 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 Moulding 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% ，
94、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 moulded 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 mould only 4% of the co
95、st 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模溫調節機Temperature controlling unit軟管Hoses冷卻迴路 2Cooling Circuit 2冷卻迴路 1Cooling Circuit 1泵Pump收集歧管Collection manifold供給歧管Supply manifold模具冷卻系統 Mould Coolin
96、g System冷卻孔道Cooling Channels入口Inlet出口Outlet入口Inlet出口Outlet噴泉管Bubbler障板管Baffle熱管Heat Pipe蒸發部位熱輸入Heat In凝結部位熱輸出Heat Out液體Liquid蒸汽Vapor燈心 ( 毛細管 )Wick ( Capillary )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
97、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 DesignD : 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冷卻孔道直徑、深度和節距 Diameter, Depth
98、 & Pitch of Cooling Channel原始設計Original Design更正設計Revised DesignAASEC. A-A原始設計Original Design定模板Cavity Plate澆道襯套Sprue Bushing定模嵌塊Cavity Insert動模嵌塊Core Insert動模板Core Plate承板Support Plate更正設計Revised Design定模板Cavity Plate澆道襯套Sprue Bushing定模嵌塊Cavity Insert動模嵌塊Core Insert動模板Core Plate承板Support Plate原始設計O
99、riginal Design動模嵌塊core insertO型環O-ring空氣囊air pocket 更正設計 (一)Revised Design ( 1 )動模嵌塊core insertO型環O-ring更正設計(二)Revised Design ( 2 )動模嵌塊core insertO型環O-ring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 Designwithout Using Frops使用限流孔梢的內歧管設計Internal Manifold Design Using Frop
100、s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 No vs. Reynolds No層流Laminar紊流Turb
101、ulent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蓋子冷卻 Cap Cooling蓋子冷卻 Cap Cooling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.
