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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
7 L7 x! h( ~8 y+ [1 G7 mHeating technique parameter setting
& {9 C: v1 Z/ z' E( J4 a, q& }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.
5 y( d. i" B& v/ \* i9 M) P5 KThe proper temperature setting differs depending on type of resin
; p0 x) ^! A0 \0 `' y$ O: Q% R* R Nmaterial, but it must be abide by a rule that temperature setting should & T8 ?: {2 c2 [! T4 v
diminish in step 10.C from nozzle to feeding resin material position.
3 _) `& h- @% v, d. n0 Z2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.
. l, @' } o( }& Q5 y( K& t尼龍等.
$ c% q* p+ ]% S$ c2 [Nozzle temperature setting should low if product line. If resin
5 k- X9 M* C' b Umaterial such as PPS, PA, cool very soon , Nozzle temperature should higher
! s6 h8 y5 J/ `4 B# fmore 10.C than the second cylinder temperature.$ s( E8 S# n+ m+ {! k1 N+ G" p/ O
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.2 w+ {4 X# u1 b t5 \# Z0 V9 g# R
Pump turning on temperature is different depending on type of injection 8 f, M2 a1 O- \3 `1 i' A
molding machine. To protect oil seal of machine it set oil temperature
( S. f: V5 {5 @+ y* b9 u第三節注射及熔膠(加料)工藝條件設定
+ |( C. I2 d0 {Injection and plastic Technique parameter setting
5 L" x8 T7 X6 H9 C6 ~! @) g: Q3 r一.注射
7 o% B3 Y# u: e e9 j# \5 fInjection
0 i; J6 z- [+ [* P! s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:
3 c4 N& M3 I: r; E* @0 [Injection is a step which inject melt resin material into mold. It * {. z9 J: B# D5 ^' L
consists of stepl,step2 ,step3,step4 and holding pressure step:2 H- d' ? Z% t) @$ P
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:$ t" C% N7 s" ]. n' E( |
Step l injects usually tunnel material, Injection Volume can be 5 q7 Z$ a2 _$ v0 K
estimated according to the weight of course it can be calculated by formula:8 `; X0 K% l$ B' }$ I7 V
L=Si=Vi/0.785Ds2
- i! Z* w4 r! S* v: E: c( D- wL:注射行程; Si: 注射行程;
; c% l( ?( z0 F- lL: injection stroke Si: injection stroke
2 f8 c9 O* y8 [# ]! BVi:理論注射容積; Ds:螺杆直徑; 5 Z& C8 I; z6 ^ r# m! a" Y0 r
Vi: injection volume of theoretical Ds: diameter of screw
/ ^; A3 g9 O7 a/ ?: T; F% N0.785:是Ω/4的值., n# c5 U" I. Y( a7 W! r
0. 785: value of Ω/4.
' ?$ A' G* {* o* `3 ]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.
+ T# x0 [/ R+ y% aBut it cost a lot of time to produce one product if every time molding
p+ q% ~; ^$ U6 `parameter is setting by calculation.2 u1 \* x1 s+ g( @5 _5 C* ]
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.9 ]/ \7 u: T$ h2 f* f, N
Step 2 inject 2/3 of product. It can lower 2/3 of product according to 8 t0 i( x. X3 F1 p% L$ v1 u& U
requirement of product. For example to prevent weld line. Molding speed + m( Q! Z; l/ i5 Y4 }- ?
and pressure on this step is the maximum of whole molding section. If 4 }2 {* j; h w# i; l* J: _
Mold suit the injection molding machine and mold structure reasonable 5 e( I# w. I, A2 C
and eject air well, pressure of this step should lower 80%. Molding speed : F- w+ }. ^( A4 [8 G3 l
setting within 55-80% but it may setting 95% for especial product., X; B3 ~ A* z: }& @: C9 v
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.
, }- ~% w1 H* m7 q2 z$ PStep3 inject remain 1/3 of product. According to product molding speed 5 ?6 Y" @. j% w' N2 [, r
and pressure lower than that of step2 To prevent flash speed and " {5 @3 T/ m2 S# i( x+ c, l# ~
pressure should decrease but it can’t shot short.
3 o6 ]! {. }7 y6 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.2 v4 ?8 A& {# F
Step4 section: Some injection machines have step5,step6 which are same
6 h) y- ^4 @, i5 a6 \as former molding speed and pressure this step should diminish and , q( Y0 E, b0 r I0 j9 @; `' f
inject once more.
' d9 h- X# o* F" b5.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.
3 H8 J# k5 S) H" c( eHolding pressure step: No matter what product there is a holding
$ c" |2 a/ V( u0 U* _) W9 Cpressure step. Any product can’t molding a same thickness. Usually the
2 ]6 _" a/ d0 [4 O5 e! mdeeper section may sink mark . To prevent this defect it should set holding
" V7 }2 o& }% J: a( a/ S+ X( ~( ^( G/ Ppressure, The injection speed of holding pressure step is slow but # `, c0 r$ t ?3 q3 D6 Y. h
holding pressure setting within 25-80% depending on sink mark
$ N9 b/ {' e$ F( H; ?3 o8 T- S4 ^* V1 l" K% T6 l7 P9 [) f6 G
within 40.C-60.C, If oil seal work on condition that high pressure and
* Z& l8 O3 D3 W: c& h y- idamaged It’s work time will be shorter, it can cause molding stable.. K) k. H: s2 q
二.熔膠段工藝' A5 I6 X2 a4 \1 Y5 ?6 }$ L# r' [$ m x
Plastic Technique
1 Y% e g$ m. u& x u7 }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.
. j% [9 A b8 DPlastic should lower 3 steps, because plastic is a step to add melt
! c' R0 p7 m: t' @2 Z2 Lresin material to cyclinder , Higher stick of resin material ,higher screw ) q* j9 r# T8 v3 U4 n
back pressure. Screw speed differs depending on decomposing temperature
: X7 D ]& N& J& q$ kof resin material ,Higher screw speed ,Higher trim force of resin,
; c* W& {4 ?7 nhigher cyclinder temperature. Some resin material may decomposes so it set 4 n' B1 `5 n% z! ]1 Y! f3 \
screw speed in mid-speed such as 45-75%, In plastic step setting screw
: j6 V4 D/ W" E. G. h, u Sback pressure is very important, Higher screw back pressure ,higher
$ o2 \. Y# D- z. E# u' Rquality of product screw back pressure make resin structure order, Molding
% d2 D* Z! P+ _5 L) a$ m! jproduct is beautiful and volume stable. But ,it maybe flow if screw : E3 x2 X7 Q. a; i% g* }
back pressure too high . So all factors should be considered when using 5 G M$ R) r+ v2 H
screw back pressure.
0 n6 p$ j" P) M, L$ d2.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.) E8 M' A- W# n, j, }
In plastic step sucking back is very important too. Sucking back
: r* P: _0 b7 Xinclude front sucking back and back sucking back It setting sucking back to
. x, H+ [7 w) S4 F5 o( r2 aprevent flow and line. It sets sucking back speed and pressure within
" n# A/ L( o' @% Q+ O7 z0 ~& v20-50% and distance within 2-5cm. TOO long distance make cyclinder # a l/ P+ W+ F1 Q. E
reserve air and cause bubble at next molding. |
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