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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
! `( Z* Y. f4 h5 S2 pHeating technique parameter setting2 h$ E' `8 P7 |/ G. _4 X* C
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.7 Y( u x5 M j) C; P1 L
The proper temperature setting differs depending on type of resin / O- l R5 S. b9 `3 \8 n$ X
material, but it must be abide by a rule that temperature setting should
0 e6 K9 b' r( {4 M' Mdiminish in step 10.C from nozzle to feeding resin material position. ; e# B" Y' [, {
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. + u9 S$ ^0 F) t1 S/ U- d& |! u& N
尼龍等.
7 J; V7 A2 ~% e* l5 xNozzle temperature setting should low if product line. If resin 6 a- f1 H8 N- P2 Q+ X9 C
material such as PPS, PA, cool very soon , Nozzle temperature should higher
/ z2 l M9 }% B# b! V Hmore 10.C than the second cylinder temperature.
3 X# Z! \+ t* Q- r' v3.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.
% S8 F8 O6 v& b& ~+ B0 F! s1 J4 ?3 xPump turning on temperature is different depending on type of injection , _- ? O$ P: e# g
molding machine. To protect oil seal of machine it set oil temperature 3 k' o8 g- {# M) M, G
第三節注射及熔膠(加料)工藝條件設定6 v; K9 A2 X" o. e( s2 K
Injection and plastic Technique parameter setting6 b3 Q6 ]3 t9 Z4 K0 c
一.注射; y* u. ?! F4 f7 S, k8 W
Injection( U$ f' S* N0 s! 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:
* b8 N4 J! z+ j( O: N8 nInjection is a step which inject melt resin material into mold. It : l! I- T" M# b' R- ]
consists of stepl,step2 ,step3,step4 and holding pressure step:9 ]# x+ F) E. _( l- _" l" n6 F8 u5 a
1.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:
9 t9 }4 S/ r' R ]6 S1 Y* MStep l injects usually tunnel material, Injection Volume can be
- s! {% { c8 D! q6 lestimated according to the weight of course it can be calculated by formula: ?7 k1 a$ d, A% r" g/ k/ |
L=Si=Vi/0.785Ds2$ y A" s; K! G$ Z& ^( l% h% f
L:注射行程; Si: 注射行程;
! f3 m' x% T$ J; xL: injection stroke Si: injection stroke2 e0 O4 G" D( n7 e* `
Vi:理論注射容積; Ds:螺杆直徑;
3 |& Z3 x& ~5 R" g6 F! XVi: injection volume of theoretical Ds: diameter of screw5 s) g, A3 ~% z
0.785:是Ω/4的值.
4 h) G" P* X- u0. 785: value of Ω/4.
# j- o- }5 V0 d7 V' Z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.
. r0 r% D, l5 j0 ?8 \( g* aBut it cost a lot of time to produce one product if every time molding
6 A8 H8 Y3 [7 T: _: kparameter is setting by calculation.
' d I8 J2 S' w: D& v0 V" s2.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.
' H( H. }# J7 g2 Q" SStep 2 inject 2/3 of product. It can lower 2/3 of product according to
+ s) o5 M3 z! l# l9 c( hrequirement of product. For example to prevent weld line. Molding speed " z7 @! Z- i8 L0 S l. R, G
and pressure on this step is the maximum of whole molding section. If
4 R: d& I" w2 u$ E: QMold suit the injection molding machine and mold structure reasonable
/ c6 w' {- @4 e% Fand eject air well, pressure of this step should lower 80%. Molding speed 4 N1 J& K4 u2 F1 e# W; \
setting within 55-80% but it may setting 95% for especial product.0 p9 Q L S5 v: G
3.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.
2 E3 }6 h( ~- n+ d8 aStep3 inject remain 1/3 of product. According to product molding speed
, U7 W# q2 L: d4 Tand pressure lower than that of step2 To prevent flash speed and
! r3 J- ^& f p% @% s, S4 a- dpressure should decrease but it can’t shot short.
) S+ B; o$ s2 N: h; x4.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.
5 ?# z! P4 D( d. f% R- U; iStep4 section: Some injection machines have step5,step6 which are same ; ?" G* M- w u
as former molding speed and pressure this step should diminish and
+ D' N; y( N% H; |9 r: minject once more." J5 u8 Q2 Q) o+ a' O H
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.
$ R; l% B4 g/ oHolding pressure step: No matter what product there is a holding + ?" L5 v# r! g+ O% `
pressure step. Any product can’t molding a same thickness. Usually the # ~2 t; R1 i" l& _
deeper section may sink mark . To prevent this defect it should set holding : W" I1 a3 K" S4 T3 x$ z
pressure, The injection speed of holding pressure step is slow but 7 R6 U# J; [* J! o3 e( O+ ^+ N
holding pressure setting within 25-80% depending on sink mark
1 O" F! q% v { L2 }! @0 v& n
% f7 a H& B( N" A4 {within 40.C-60.C, If oil seal work on condition that high pressure and
: r0 L$ Q2 f- G1 Jdamaged It’s work time will be shorter, it can cause molding stable.& S2 [: {0 \3 P9 P+ ]
二.熔膠段工藝
# ]; W7 Q7 R [Plastic Technique
6 y% W4 V0 q; ^. p. r' `( K& Z1.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.
% t/ a$ ^: ?6 a+ o* O/ FPlastic should lower 3 steps, because plastic is a step to add melt
; ^. m5 @9 E: {0 Tresin material to cyclinder , Higher stick of resin material ,higher screw 3 H3 L( `' Z# d* C4 O
back pressure. Screw speed differs depending on decomposing temperature
5 `1 x/ u* |# h( T0 l6 q4 aof resin material ,Higher screw speed ,Higher trim force of resin, $ l, }$ V: @. x4 F& ^. T# H
higher cyclinder temperature. Some resin material may decomposes so it set 3 Q a1 l8 {$ l5 m
screw speed in mid-speed such as 45-75%, In plastic step setting screw
, W# f; \: E% {1 }5 ]back pressure is very important, Higher screw back pressure ,higher
* W) X ?" O- P8 C8 P( O9 v0 [! dquality of product screw back pressure make resin structure order, Molding
& u* Y. O9 [( Z. {. B; E! tproduct is beautiful and volume stable. But ,it maybe flow if screw % Y6 |& k m3 }
back pressure too high . So all factors should be considered when using 2 ?8 o7 [$ J# R
screw back pressure.
) g# ~6 I6 d5 M& O3 y; v2.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.
, ]$ ^9 ]6 r; ?4 X+ g, mIn plastic step sucking back is very important too. Sucking back ( B% R0 X3 X0 W7 z0 R. T J% \
include front sucking back and back sucking back It setting sucking back to 1 V: M7 k3 U- y. _1 i
prevent flow and line. It sets sucking back speed and pressure within
- h& ~/ p5 ^8 O$ G0 P20-50% and distance within 2-5cm. TOO long distance make cyclinder , y- h7 Q( b' w& @( G
reserve air and cause bubble at next molding. |
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