塑胶产品设计-PPT课件

壁厚設計 Wall Thickness Design
差 [Poor]
較好 [Better]
最好 [Best]
掏空設計(1) Coring Out Design (1)
原設計 [Original]
改進設計 [Improved]
掏空設計(2) Coring Out Design (2)
差 [Poor]
遠離側壁之凸轂(熱塑性塑膠)
Boss Away From Wall( Thermoplastics )
I
E H
G F
C B
FD A
A =凸轂附著處壁厚
wall thickness B =凸轂外環直徑
(含底部修整圓弧半徑) dia. of boss over radii
C = 0.5 A D=2B E = 1 - 2 deg F = 0.13 mm ( radius ) G = 0.95 D H = 0.3 G min. to G max. I = 0.5 A
改進 [Improved]
外側凸轂 Outside Boss
A ( DIA )
A'
A'
B=A B= 2A ( max. )
B
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 )
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 that will not distract from the consumer’s 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
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 sticky materials. Smaller draft angles can be used on soft, ductile, and slippery materials.
突出件壁厚 Thickness of the Projection
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 recommended 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 part’s NW thickness .
假如需要更大的強度,可增加肋的數目 If more strength is required, add additional ribs.
肋的設計 (二 ) Rib Design ( 2 )
角板設計 (三 ) Gusset Design ( 3 )
與側壁相連之凸轂(熱塑性塑膠) Boss at Wall ( Thermoplastics )
肋的底部厚度 Bottom Thickness of Rib
(A)
(B)
1.5WD
1.2WD
W
2.5W
W
0.5W
肋的設計 (一 )
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
塑膠產品設計 Plastic Part Design
壁厚 Wall Thickness
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 possible thickness can be scientifically determined by CAE.
Wall Thickness, Gussets
Conventional
0.080 to 0.125 in (2.0 to 3.2 mm)
t gusset 0 . 6 t wall
h 4 t wall r 0 .375 mm


1o 2
Thinwall:
0.050 to 0.080 in
t boss 0 . 6 t wall
Conventional
0.080 to 0.125 in
h 4 t wall r 0 . 375 mm
(2.0 to 3.2 mm)


1o 2
OD 2 ID
Thinwall:
0.050 to 0.080 in
< 0.050 in
(1.2 to 2.0 mm)
突出件高度 Height 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 molding perspective, the height of projections should be limited to 2.5 to 3 times the part nominal wall thickness.
(1.2 mm)
tboss 0 .6 t wall t wall
h 4 t wall
r 0 .375 mm 0 .6 * t wall


1o 2

1o
OD 2 ID
t boss t wall h 4 * t wall r 0 . 6 * t wall 1o OD 2 ID
L H
A'
A'
KE
JD F
I
G
A C
B
Section A'-A'
A =凸轂附著處壁厚
wall thickness B =凸轂外環直徑
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
肋厚和內圓角半徑的影響 The Effect of Rib Thickness
& Fillet Radius
內圓角半徑 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。
< 0.050 in
(1.2 to 2.0 mm)
(1.2 mm)
t gusset 0.6 twall twall
h 4 twall
r 0.375 mm 0.6 * twall


1o 2

1o
t gusset t wall h 4 * t wall r 0 . 6 * t wall 1o
壁厚不均 Non-uniform 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, including hesitation, short shot, sink mark, blush, jetting, warpage and long cooling time etc., can be predicted, directly or indirectly, by using CAE.
< 0.050 in (1.2 mm)
trib 0.6 twall twall
h 4 twall
r 0.375 mm 0.6 * twall


1o 2ቤተ መጻሕፍቲ ባይዱ
1o
t rib t wall h 4 * t wall r 0 . 6 * t wall 1o
Wall Thickness, Bosses
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 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%.
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.
突出件壁厚 Thickness of the Projection
有些情形，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 .
Wall Thickness, Rib
Conventional
0.080 to 0.125 in (2.0 to 3.2 mm)
t rib 0 . 6 t wall h 4 t wall r 0 . 375 mm


1o 2
Thinwall:
0.050 to 0.080 in (1.2 to 2.0 mm)