浇口数目
在型腔能夠完滿充填的前提下，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.
为了減少浇口数目，每一浇口应就塑流力所能及的流长/壁厚 比之內，找出可以涵蓋最大产品面积的进浇位置。
熔接线冷料井 Weld Slug Well
熔接线冷料井 [Weld slug well] 对头熔接线 [Butt weld]
Air Traps
积风
排气
Vent
A'
Feed Runner
进料流道
塑料成品
Plastic Part
A C A'
排氣孔
Vent
D
B SEC. A'-A'
大部份热塑性塑料
Most Thermoplastics A 0.08 mm B 3.18 mm C 12.7 mm D 0.25 mm
万学超
2007.8.1
浇注系统的优先順序
Priorities of Filling System 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) 噴嘴设计 (Nozzle Design)
熔胶波前推进
Melt-Front Advancement
充填模式,积封和熔接线
Filling Patterns, Air-Traps and Weld Lines Location
Weld Lines
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
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.
使用击片浇口以避免噴流
Avoid Jetting by Using Tab Gate
使用适当的浇口形状以避免噴流
Avoid Jetting by Prห้องสมุดไป่ตู้filing Gate Properly
差的 Poor
好的 Good
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)
Reinforcement Tensile Strength Type Retention (%)
0%GF 20%GF 30%GF 0%GF 30%GF 0%GF 10%GF 30%GF 0%GF 30%GF 0%GF 10%GF 40%GF 0%GF 10%GF 30%GF 86% 47% 34% 80% 40% 99% 86% 64% 100% 62% 83% 38% 20% 83-100% 87-93% 56-64%
(A) (B)
W 1.5WD 1.2WD
肋的底部厚度
2.5W
W
0.5W
肋的设计 (1 )
Rib Design ( 1 )
A
C t
B D E F
A
t = wall thichness B = 0.5t C=3t
D=2B E = 0.13 mm(radius) F = 1.5 - 2 deg
假如需要更大的強度,可增加肋的数目 If more strength is required, add additional ribs.
Poor Design Causing Jetting
Gas Pin Gate
Part : Handle, Refrigerator Material : ABS Problem : Jetting Mark
气辅成型冰箱把手
浇口及气針入口
浇口太小,导致噴流痕产生
挠曲刚性
各种一体成型的內锁件 能增加薄辕的刚性。
A variety of molded-in interlocks can add stiffness to thin-wall housing designs.
结构设计和薄辕成型产品
Structural Design & Thin-wall Molding Parts
I
H G
E
F C B
F A
D
Outside Boss
A ( DIA )
外側击辕
A'
A'
B=A
B= 2A ( max. )
B
Section A'-A'
Flexural Rigidity
1 M r EI
Where 1/r : 梁的曲率 curvature of the beam M : 弯曲力矩 bending moment E : 弹性模数 modulus of elasticity I : 断面积对中立轴的惯性矩 moment of inertia of the cross- sectional area with respect to the neutral axis EI : 挠曲刚性 flexural rigidity
壁厚不均
壁厚设变
Wall Thickness Design
差 [Poor]
较好 [Better]
最好 [Best]
掏空掏空 (1)
Coring Out Design (1)
原设计 [Original] 改进设计 [Improved]
掏空设计 (2)
Coring Out Design (2)
差 [Poor]
Non-uniform 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.
浇口设计(减少滯流效应]
Gate Design to Avoid Hesitation
浇口 gate 薄 thin
厚 thick 薄 thin
厚 thick
浇口 gate
差的设计 Poor
好的设计 Good
浇口设计(避免凹陷和氣泡)
Gate Design to Avoid Sink Mark & Void
原设计 [Original] 更改设计 [Revised]
材料 [Material] : PC-GF50
典型对头熔接线伸张強度保留值
Typical Butt Weld Tensile Strength Retention Values
Material Type
PP PP PP SAN SAN PC PC PC PSF PSF PPS PPS PPS PA66 PA66 PA66
Rib Design ( 2 )
肋的设计 (2)
肋的设计 (3)
Rib Design ( 3 )
与側壁相连之击辕 (热塑性塑料)
Boss at Wall ( Thermoplastics )
L H A'
A' E
K J D F A
I C B
G
A = 击辕附著处壁厚 wall thickness B = 击辕外环直径 dia. of boss over radii C = 0.5 A D =2B E = 1 ~ 2 deg F = 0.13 mm ( radius ) G =D H = 0.8 A I =A/4 J =2B K = 0.3 ~ 1 J L = 0.5 A
Melt ” Flipper ”
导致平直产品的浇口设计
Gate Design for Flat Part
最坏的 Worst
中心浇口 Center Gate 坏的 Worse 侧浇口 Edge Gate 薄模浇口 Film Gate 扇形浇口 Fan Gate 最好的 Best
较好的 Better
模具设计的优先順序
Priorities of Mold Design
浇注系統设计 (Filling System Design)
排氣系统设计(Venting System Design)
冷卻系統设计 (Cooling System Design)
脫模系統设计 (Ejecting System Design)
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.
结构设计是薄辕成型零件的基础。