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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8 X A6 E X' q6 B2 ]6 |- f
Heating technique parameter setting
8 [1 ~% F( I2 y0 e* e1 D1.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.
% a J6 p. r" `4 s1 `. q$ qThe proper temperature setting differs depending on type of resin
! S! V" B$ j! N! m7 Bmaterial, but it must be abide by a rule that temperature setting should $ o5 i3 l7 }3 B
diminish in step 10.C from nozzle to feeding resin material position.
/ t: H( B) M3 ?' K/ M/ R0 O! l2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.
# Y- ], I* H$ P& X1 M/ Z+ J尼龍等.
6 X- Y' ? `" t* j5 bNozzle temperature setting should low if product line. If resin
: Q0 m& z$ \, |( N& rmaterial such as PPS, PA, cool very soon , Nozzle temperature should higher
% ~$ |+ W5 j' C4 Gmore 10.C than the second cylinder temperature., M* x# l$ v$ k) P
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.
: i. C8 D0 f* U6 e8 o( [Pump turning on temperature is different depending on type of injection
1 C8 g$ d5 [8 [% D( b6 L. hmolding machine. To protect oil seal of machine it set oil temperature , e; o8 [/ H$ a9 L) x
第三節注射及熔膠(加料)工藝條件設定$ X0 n( L% d, f% \* \; `% c
Injection and plastic Technique parameter setting* i# g$ @0 F0 a5 }* n
一.注射/ w9 A6 a# G. k7 t
Injection
; W) i# ^4 e- A1 T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 b" ~6 O8 d$ @# Q
Injection is a step which inject melt resin material into mold. It 7 v$ Y) B6 [$ K/ Q. N
consists of stepl,step2 ,step3,step4 and holding pressure step:! _) E2 {8 F& g& q
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:& S' h, L! d& m7 @% @
Step l injects usually tunnel material, Injection Volume can be
$ @+ z9 i, T2 i, |. s* pestimated according to the weight of course it can be calculated by formula:
% e1 `( K _/ j! M- EL=Si=Vi/0.785Ds2' E/ b4 m' l% r
L:注射行程; Si: 注射行程;
5 V* N7 B! t" Y! v* F- W3 B0 uL: injection stroke Si: injection stroke# s, W# q" b* Q: ?
Vi:理論注射容積; Ds:螺杆直徑;
6 q9 G) [7 w F8 ]& `Vi: injection volume of theoretical Ds: diameter of screw$ `8 X) I/ g5 i! ?- ]# g* U1 i6 A
0.785:是Ω/4的值.
) S! M) e2 ^! U1 ?" j$ L# s8 J% D0. 785: value of Ω/4.6 r- O* e; e- P. s* L2 X1 l
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.
" `0 b) F% L3 ]1 YBut it cost a lot of time to produce one product if every time molding : ]6 x. K; H# M L/ Q$ K) P
parameter is setting by calculation.
7 M0 a2 P! ]' `' p! e2.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.4 r2 c/ l/ ]5 V K
Step 2 inject 2/3 of product. It can lower 2/3 of product according to " q- _: {, ^1 C, ?/ z, r n% T% c
requirement of product. For example to prevent weld line. Molding speed & ~" S: R) L) W+ E9 V
and pressure on this step is the maximum of whole molding section. If
1 V7 V, \, }9 u8 _2 Q: KMold suit the injection molding machine and mold structure reasonable
, ^1 n6 U9 v, Eand eject air well, pressure of this step should lower 80%. Molding speed
9 I9 ^ H/ ~5 i4 Ysetting within 55-80% but it may setting 95% for especial product.& T0 p' C/ |+ }: `
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." C; B( B4 n7 E& B1 Z1 m- B# r
Step3 inject remain 1/3 of product. According to product molding speed ; w9 f# ~- a$ B! K/ @
and pressure lower than that of step2 To prevent flash speed and * n. m! f9 ^. I+ @& a9 Q( g( i
pressure should decrease but it can’t shot short.8 o7 n9 `) d( e, p" h- Y
4.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.4 e9 X/ r" r# H+ _ X# h& i
Step4 section: Some injection machines have step5,step6 which are same
% ]* \. A1 S# ras former molding speed and pressure this step should diminish and
, L# I- h+ ]" }8 f6 U4 Rinject once more.
2 [: M- E0 _, N/ `0 [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.7 n+ i, i$ L, L/ J% k
Holding pressure step: No matter what product there is a holding 4 H ^( n8 i% o S3 G1 `" v
pressure step. Any product can’t molding a same thickness. Usually the ) A1 P7 Z% Y0 s% [
deeper section may sink mark . To prevent this defect it should set holding
+ E7 q, {* y0 Kpressure, The injection speed of holding pressure step is slow but
+ s! s J, A# U( E' }/ o3 _holding pressure setting within 25-80% depending on sink mark0 g& j& h. {1 ~$ _% O8 E( x0 a
; f% w. l# `+ R3 ]$ W- k
within 40.C-60.C, If oil seal work on condition that high pressure and
$ x: F! ^6 G+ c# Bdamaged It’s work time will be shorter, it can cause molding stable.
% j) N7 F1 q- C/ f二.熔膠段工藝7 J3 w! o9 f8 N3 ]% H" u2 d4 O8 G
Plastic Technique# {; ~% g' ]8 Z' F: ^4 u
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.
; n+ }8 U5 q* m F nPlastic should lower 3 steps, because plastic is a step to add melt
$ @! s6 h) q( w$ Kresin material to cyclinder , Higher stick of resin material ,higher screw
/ w5 K3 z2 T; `back pressure. Screw speed differs depending on decomposing temperature
5 Z) {# c# D9 h, J9 Eof resin material ,Higher screw speed ,Higher trim force of resin,
0 Q) H5 x1 n; M% t$ t9 m' Shigher cyclinder temperature. Some resin material may decomposes so it set 3 E$ h2 P5 E7 D- u# X' d/ y. v
screw speed in mid-speed such as 45-75%, In plastic step setting screw
: [! L% ?$ n0 |) T" Q8 ~back pressure is very important, Higher screw back pressure ,higher
" `$ q8 n3 G. b1 s/ o- P) i* b" d3 Zquality of product screw back pressure make resin structure order, Molding
$ V( V& Y$ H# S: ~product is beautiful and volume stable. But ,it maybe flow if screw * @; n" W, s$ |! n6 V1 \! ^
back pressure too high . So all factors should be considered when using 1 y- o& f9 _. G3 o. Z
screw back pressure.
7 \. x! b/ [3 M6 G0 i2.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., a) T9 E( A6 X% W
In plastic step sucking back is very important too. Sucking back
: n% B% [$ [: c" q* x" D7 einclude front sucking back and back sucking back It setting sucking back to * Q' T5 w/ W& W5 S
prevent flow and line. It sets sucking back speed and pressure within
$ e) E+ Y& H; |4 p20-50% and distance within 2-5cm. TOO long distance make cyclinder
7 {- l5 t: X+ Y, @4 O9 e- B8 ureserve air and cause bubble at next molding. |
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