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发表于 2007-3-30 08:16:27
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来自: 中国台湾
加熱工藝條件設定/ ^2 o2 M. ^: {* G
Heating technique parameter setting
1 Q' B# p1 h) r @1.加熱段溫度設定必須按照産品所使用的原料的不同而不同,但却必須遵循一個這樣的規則,即由射口筒到進科段溫度是逐步遞减的.且遞减溫度是以10.度爲單位.
X. c' }% [3 f. D) S, s1 q. w8 ~The proper temperature setting differs depending on type of resin
. }5 t: y E; B) f- z7 m- ymaterial, but it must be abide by a rule that temperature setting should . f/ ]' O w1 {6 q( W
diminish in step 10.C from nozzle to feeding resin material position. % v1 G- A3 _1 {& F
2特殊情况下.如料頭抽絲,則射口筒溫度應降低,如果是比較特殊的原料冷凝比較快的.則射口筒溫度則不止比第二節法蘭溫度高10度.比如PPS.
3 O7 b/ S. ]* L% r: i& y% l尼龍等.8 V2 n/ _0 a$ T1 p0 Z
Nozzle temperature setting should low if product line. If resin 0 Z$ v7 `# u5 A# p4 @
material such as PPS, PA, cool very soon , Nozzle temperature should higher 3 o; W2 m6 }. t, o2 ^9 N# d
more 10.C than the second cylinder temperature.; Q6 i3 @& O; c/ Y3 @' O U
3.機台馬達啓動溫度視乎機台不同而不同,一般出于對機台油路中的油封保護需要,油溫最好能控制在40度-60度,以免油封長期高壓而變化,縮短使用壽命,造成成型不穩定.
: y J0 E, }* e* [$ H6 hPump turning on temperature is different depending on type of injection * z% ]6 \! f0 w4 i5 l' {8 G
molding machine. To protect oil seal of machine it set oil temperature : y e( g6 H4 n+ @& \
第三節注射及熔膠(加料)工藝條件設定
' R9 m% q9 T2 X" ZInjection and plastic Technique parameter setting
m) W r' Q) j, _" K一.注射1 K0 L" [4 t$ O2 Q5 p. Z
Injection% }# i5 @4 }3 [3 a
注射是把塑料原料經加熱後射進模腔的過程,它一般可分爲第一級,第二級,第三級,第四級及保壓幾段:
5 K# K+ R$ [8 T# M) w0 q0 c2 TInjection is a step which inject melt resin material into mold. It
* b. a/ {8 q. B Jconsists of stepl,step2 ,step3,step4 and holding pressure step:
9 B( V/ c* ^- x6 y5 e( B1.第一級注射一般是注射料頭段.具注射量一般可根據料頭的輕重來估計其行程,當然也可以依據公式來計算,如公式:' h7 g$ A- G, ~9 N" ?
Step l injects usually tunnel material, Injection Volume can be 1 U6 u% \* _; y8 Z9 k
estimated according to the weight of course it can be calculated by formula:
& {0 W# u/ H, ^2 l: P. tL=Si=Vi/0.785Ds25 |- l4 c/ h0 J& m- H
L:注射行程; Si: 注射行程;2 a$ ]% T$ ?7 A/ J- q
L: injection stroke Si: injection stroke
+ p# u4 F) t- c2 t wVi:理論注射容積; Ds:螺杆直徑; - p& u: q/ q; E* X' s
Vi: injection volume of theoretical Ds: diameter of screw6 Z, r0 `5 a% l4 g5 B
0.785:是Ω/4的值.6 L( X3 N. _; B* x- q" \5 D
0. 785: value of Ω/4.
; J4 J3 C7 Z+ o1 i) v) G當然,如果我們在成型時每設定一個參數都要計算一次,要成型出一個産品就要幾個小時才能完成了./ x- G0 _7 h1 \! G* ~# `- f# M
But it cost a lot of time to produce one product if every time molding & t6 P l+ _- w! I7 U
parameter is setting by calculation.% n; [! n# c5 }3 V4 y
2.第二級是注塑産品約2/3的階段,當然,根據産品特殊需要,也允許成型不到2/3階段,比如避免結合綫問題,這一階段的成型速度及壓力一般是整個成型段的最大值段,如果排的産品與機台基本是相吻合的.模具結構合理,排氣良好,這一段的壓力一般也不會超過80%.速度側視産品需變,可能大到95%也可,自然一般都是在55%-80%間.
+ Y! P0 c; n: _( S! D: rStep 2 inject 2/3 of product. It can lower 2/3 of product according to & h. V% l1 o' b5 }& n- G& ]9 m
requirement of product. For example to prevent weld line. Molding speed
% ]: ?5 c' Z" Z( z# b$ y" dand pressure on this step is the maximum of whole molding section. If . A1 ]. Q Q. r6 w! E7 ^2 k3 q
Mold suit the injection molding machine and mold structure reasonable
# g9 J) b! ?- R/ h& E. `* e. \and eject air well, pressure of this step should lower 80%. Molding speed
: U( `6 {- U0 U: u* {setting within 55-80% but it may setting 95% for especial product.
# A( y1 u' W7 H3.第三段是注射餘下的1/3段,其速度和壓力根據産品的需要,一般是小于第二段,速度和壓力存在于一個往下降的過程.主要是爲了防止産品毛邊的産生,但同時又必須把産品充填飽滿.! J7 i0 v4 q% [$ C! Z
Step3 inject remain 1/3 of product. According to product molding speed . e+ J* |" U: W
and pressure lower than that of step2 To prevent flash speed and # ^" T4 U& Y/ h U- y, k! g3 D! R
pressure should decrease but it can’t shot short.
- Q j" g+ L: ]& A7 i0 C4.第四段:一般有機台還有第五,第六段,這段的成型速度和壓力相同前,都存在兩段一個遞减過程.其作用都是起到一個再次充滿的作用.
6 A+ ? S$ \# HStep4 section: Some injection machines have step5,step6 which are same
- _& {; j% I3 R `1 _/ Q6 [as former molding speed and pressure this step should diminish and
& e0 g' Q5 a: f) B, o0 v" Oinject once more./ y( X9 j$ n) J8 _* u
5.保壓段:不論成型什麽産品,都存在一個保壓過程.任何産品都不同程度的存在一個厚薄不一的問題,正常情况下,較厚的部分都可能存在一個收縮凹陷的現象,爲了解决這種現象,就應應用到保壓,保壓一般來講都應用較慢的射速,而壓力的設置則應看縮水的情况如何,小到25%,大到80%都有可能.0 Y7 f& x. W6 A' a5 P4 E4 \% _
Holding pressure step: No matter what product there is a holding " [0 ~0 s0 i3 j3 Z% P
pressure step. Any product can’t molding a same thickness. Usually the
5 A# c3 S3 E1 a q+ R6 ?deeper section may sink mark . To prevent this defect it should set holding
- x! v y6 h4 o& Xpressure, The injection speed of holding pressure step is slow but & ]+ \" I- p# H5 h+ }/ T
holding pressure setting within 25-80% depending on sink mark
2 [" z4 k, v5 ]" @+ o# V [) t$ J4 y# x
within 40.C-60.C, If oil seal work on condition that high pressure and 4 \, N, A$ R8 B$ ~
damaged It’s work time will be shorter, it can cause molding stable.
6 ^; C# ]# O1 a# S |: c; j8 o二.熔膠段工藝6 {& o$ k0 B! V& H
Plastic Technique, f' t+ Y1 q3 Q" F! z8 @5 ?
1.再複雜的熔膠旋轉過程最多不會超過三段,因爲熔膠本身就是存在于把膠熔進料筒的過程,如果原料粘度大,熔膠壓力則大,但速度則應取决于原料的分解溫度,熔膠速度越快,原料中的剪切力則會越大,料管溫度則越高,局部原料産生分解的可能性則會越大,故一般熔膠會采用中速爲宜,如45%-75%,熔膠同時會碰到一個比較重要的環節,那就是背壓的使用,産品精度要求越大,背壓的使用則更大,背壓可使原料分子間結構更緊密,成型出的産品則尺寸更穩定,外觀越好.當然,背壓太大,則會産生流涎,所以背壓的使用又應考虙到其它原因.
" k# l2 ^4 s9 J1 T, [' Z9 ?Plastic should lower 3 steps, because plastic is a step to add melt
# O' U# Y) G) D6 y- n8 y. ?resin material to cyclinder , Higher stick of resin material ,higher screw
& ~+ ~6 D( O2 O; R& Fback pressure. Screw speed differs depending on decomposing temperature
3 C, o9 O5 B! J% Pof resin material ,Higher screw speed ,Higher trim force of resin, 8 R4 j( Y( j# K
higher cyclinder temperature. Some resin material may decomposes so it set ' n/ j$ s( F h' a6 i W
screw speed in mid-speed such as 45-75%, In plastic step setting screw
- P. ?5 Z4 [% ~3 s0 m4 R1 Vback pressure is very important, Higher screw back pressure ,higher
, L% r- s5 w L0 Tquality of product screw back pressure make resin structure order, Molding
" {7 X+ i5 ]8 g$ R0 fproduct is beautiful and volume stable. But ,it maybe flow if screw . c: J! k' s: P, ]
back pressure too high . So all factors should be considered when using
2 T: s+ A1 q9 Uscrew back pressure.
# i, G5 w, ~4 E2.熔膠過程還有一個比較重要的環節,那就是松退,松退分前松退和後松退,其作用一般是爲了防止流涎和抽絲,設定值速度和壓力都在20%-50%間,設定的行程一般在2-5cm間,太長的行程可能會使料筒裏面貯存空氣,導致下一模出現不期望的氣泡.+ ], Q: j) Q1 c6 f' t
In plastic step sucking back is very important too. Sucking back
& ^8 _4 d4 I5 I4 Tinclude front sucking back and back sucking back It setting sucking back to , g, |( |9 V! H
prevent flow and line. It sets sucking back speed and pressure within ) G5 C! U+ w- j$ u3 j& | x; _. t9 U" L
20-50% and distance within 2-5cm. TOO long distance make cyclinder ' [1 W; x+ `% b
reserve air and cause bubble at next molding. |
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