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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
# k7 l! N2 W, d9 mHeating technique parameter setting8 o9 b p' M3 f5 ]1 e
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.0 B+ R' m& s% e4 E) |- M
The proper temperature setting differs depending on type of resin
+ d0 G- r4 A8 r* ]4 I( A* ]$ dmaterial, but it must be abide by a rule that temperature setting should 6 H3 l9 L& i* g
diminish in step 10.C from nozzle to feeding resin material position. * \ `' t0 c, V+ X B
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.
% `' }- `7 p% F1 Z+ S7 }0 e尼龍等.# W1 L& O4 D7 N3 O9 ]
Nozzle temperature setting should low if product line. If resin
* d* W8 u/ M/ F1 Q* {6 ]material such as PPS, PA, cool very soon , Nozzle temperature should higher * T4 N' ]8 z# B7 A- H* B
more 10.C than the second cylinder temperature. U+ J8 C) e9 U9 }
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.; _% a8 i) X4 x& ]$ z
Pump turning on temperature is different depending on type of injection
* P; W X h8 O! l4 c/ w5 t& jmolding machine. To protect oil seal of machine it set oil temperature * j( ?% O, H- M" R
第三節注射及熔膠(加料)工藝條件設定
# v! w! y/ v9 T8 v& x8 x" }Injection and plastic Technique parameter setting0 W1 ]4 k4 ^! f2 o" {0 _3 W1 \
一.注射3 X$ @$ v3 X1 B; U4 v
Injection
6 ^- D$ \, w7 k9 R0 A1 Q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:4 ~# a: H+ p9 G
Injection is a step which inject melt resin material into mold. It
$ s4 B" A/ G0 [& Y2 |* }consists of stepl,step2 ,step3,step4 and holding pressure step:
5 ^6 {% [' `7 v* R1 r/ N$ p1.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:, Q5 Y' n0 J* X6 j- M( E1 l& N
Step l injects usually tunnel material, Injection Volume can be ( w7 c; E6 G0 r! P3 n+ W+ ~
estimated according to the weight of course it can be calculated by formula:
. V( w6 Y" U. W% dL=Si=Vi/0.785Ds2% c9 t! S6 q9 |3 f. ~/ D
L:注射行程; Si: 注射行程;1 W$ O5 ^1 _& p/ D% }, @4 G
L: injection stroke Si: injection stroke1 Z: x& b& I5 \, Y0 Q1 {9 I
Vi:理論注射容積; Ds:螺杆直徑; 3 N Q+ ~: ~/ S) \+ T5 n9 q* `
Vi: injection volume of theoretical Ds: diameter of screw2 p& F1 h3 |( B. T! ^
0.785:是Ω/4的值.
6 _+ s! @+ B) B( D8 t0. 785: value of Ω/4. I4 A" Y0 L, _! W! O
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.
1 r- ]1 [6 Z" g9 `6 uBut it cost a lot of time to produce one product if every time molding
9 {' W0 p i: E! b8 Uparameter is setting by calculation.
% [+ M5 B: `# R# z9 r a2.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.; U d* n9 w$ H7 O8 D: b
Step 2 inject 2/3 of product. It can lower 2/3 of product according to * \2 I8 d" X* f* W* A
requirement of product. For example to prevent weld line. Molding speed J: D0 U' R. ~& Q& I! h5 L+ A O$ m
and pressure on this step is the maximum of whole molding section. If
7 I$ [" E( @% n! m% L6 aMold suit the injection molding machine and mold structure reasonable
* _+ V9 `- G, uand eject air well, pressure of this step should lower 80%. Molding speed
& g* A1 I0 G" i* C2 t4 s9 ^+ p0 fsetting within 55-80% but it may setting 95% for especial product.
+ A- o. j/ E5 _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., }8 S$ A+ \2 ^2 H+ g7 W
Step3 inject remain 1/3 of product. According to product molding speed
! D- n9 X# S& b' t& n* [and pressure lower than that of step2 To prevent flash speed and
: ^- v+ ~ ]* J! w5 [pressure should decrease but it can’t shot short.
6 N: x' }( B' Y8 K; I4.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./ M8 b. n. N1 S
Step4 section: Some injection machines have step5,step6 which are same
t4 L. \, [* d4 f N vas former molding speed and pressure this step should diminish and
6 i0 k$ G% x% }2 D1 w- ~% [. ninject once more.5 a% g" @. h) R0 p& c
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. f0 M. B2 u/ A: j, [
Holding pressure step: No matter what product there is a holding + E& w( f! a; q @% c0 C
pressure step. Any product can’t molding a same thickness. Usually the
0 q6 W' X" R* s6 R% h8 ]0 Gdeeper section may sink mark . To prevent this defect it should set holding 9 t' W& R# S6 D0 c+ O+ c8 r
pressure, The injection speed of holding pressure step is slow but 9 {. T% O4 f6 t. f0 w# b2 P
holding pressure setting within 25-80% depending on sink mark
7 X/ i8 q0 w6 z
) q+ Z6 \4 j7 M+ ~- _/ `within 40.C-60.C, If oil seal work on condition that high pressure and 2 X, p9 M; ]& t
damaged It’s work time will be shorter, it can cause molding stable.# T7 O' w3 N2 i
二.熔膠段工藝4 \$ [7 u- n7 s1 n! b% h+ d R
Plastic Technique$ A1 L, t2 J+ w6 \- ~9 c
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.6 O7 e m6 V5 _9 t% b
Plastic should lower 3 steps, because plastic is a step to add melt
2 ]- c& _2 i1 J, `% Y5 \# j* Y# j9 \" bresin material to cyclinder , Higher stick of resin material ,higher screw
4 A) c$ k# j3 S3 m5 G$ y; h2 xback pressure. Screw speed differs depending on decomposing temperature / O4 a$ j$ w: M! N! w& G0 Y
of resin material ,Higher screw speed ,Higher trim force of resin,
6 i) V) t" |9 [6 n' Thigher cyclinder temperature. Some resin material may decomposes so it set 6 }4 l9 X" s, d- ^
screw speed in mid-speed such as 45-75%, In plastic step setting screw $ K5 c4 y( u3 p$ ~
back pressure is very important, Higher screw back pressure ,higher
# J% W1 i2 c0 _quality of product screw back pressure make resin structure order, Molding
. m+ e. W" p( T% c) ^product is beautiful and volume stable. But ,it maybe flow if screw : @( f" f, X1 V$ W
back pressure too high . So all factors should be considered when using / f, _4 S9 c, H* C# E
screw back pressure. ' M! i9 q( \/ T. K: x. K4 I+ ^5 d g
2.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.0 j* Q6 R' [- k" f) p
In plastic step sucking back is very important too. Sucking back 8 P3 H5 Y" f) U2 _ n# M2 \6 K3 v
include front sucking back and back sucking back It setting sucking back to
) S& [+ s/ p( p5 @8 hprevent flow and line. It sets sucking back speed and pressure within
' h: G( }7 u! \8 X5 y& p5 P) U+ m20-50% and distance within 2-5cm. TOO long distance make cyclinder 4 u( I7 U: }0 i! s* Z4 |
reserve air and cause bubble at next molding. |
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