塑膠射出成型問題診斷與產(chǎn)品模具設(shè)計-文庫吧在線文庫
【正文】 )流道尺寸設(shè)計 (3) Runner Sizing (3)流道尺寸設(shè)計 (4) Runner Sizing (4)流道尺寸設(shè)計 (A1) Runner Sizing (A1)G : 重量 weightS : 零件厚度 thicknessD39。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(shù)目是愈少愈好。Where 1/r : 樑的曲率 curvature of the beamM : 彎曲力矩 bending momentE : 彈性模數(shù) 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 RigidityA variety of moldedininterlocks can add stiffness to thinwall housing designs.各種一體成型的內(nèi)鎖件能增加薄殼的剛性。Nonuniform wall thickness is the biggest trouble maker in plastic injection molding. This is especially true to thinwall 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Nonuniform Wall Thickness壁厚設(shè)計Wall Thickness Design差 [Poor]較好 [Better]最好 [Best]掏空設(shè)計 (1) Coring Out Design (1)改進(jìn)設(shè)計 [Improved]原設(shè)計 [Original]差 [Poor]改進(jìn) [Improved]掏空設(shè)計 (2) Coring Out Design (2)氣泡或 /和凹陷的形成Void or/and Sink Mark Forming氣泡 ( Void ) 凹陷 ( Sink Mark )肋厚和內(nèi)圓角半徑的影響The Effect of Rib Thickness Fillet Radius肋的底部厚度Bottom Thickness of RibW (A) (B)肋的設(shè)計 (1 )Rib Design ( 1 )t = wall thichnessB = C= 3 tAAD = 2 BE = mm(radius)F = 2 deg假如需要更大的強(qiáng)度 ,可增加肋的數(shù)目If more strength is required, add additional ribs.FBDEC t 肋的設(shè)計 (2)Rib Design ( 2 )肋的設(shè)計 (3)Rib Design ( 3 )與側(cè)壁相連之凸轂 (熱塑性塑膠 )Boss at Wall ( Thermoplastics )A = 凸轂附著處壁厚 wall thicknessB = 凸轂外環(huán)直徑 dia. of boss over radiiC = AD = 2 BE = 1 ~ 2 degF = mm ( radius )G = DH = AI = A / 4J = 2 BK = ~ 1 JL = A LHA39。A39。結(jié)構(gòu)設(shè)計是薄殼成型零件的基礎(chǔ)。As long as the cavity is able to be filled appropriately, gates are the less the better.為了減少澆口數(shù)目，每一澆口應(yīng)就塑流力所能及的流長 /壁厚比之內(nèi)，找出可以涵蓋最大產(chǎn)品面積的進(jìn)澆位置。 : 參考直徑 reference diameterG( g ) D39。 ( mm )fo
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