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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
$ _ }) Z1 @( _* K7 E6 oHeating technique parameter setting
' K" W% t0 p- A; Y) C2 s1.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.; `+ _# b( o/ l
The proper temperature setting differs depending on type of resin
/ _. O. n, U: ^5 V n2 }2 b' G3 G% smaterial, but it must be abide by a rule that temperature setting should 1 h# P. C8 r/ f0 Y
diminish in step 10.C from nozzle to feeding resin material position.
0 E7 o, r i0 M" ^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.
' x: K8 L6 A1 t7 e$ S3 F: y尼龍等." \: d7 a1 N" \8 v0 `
Nozzle temperature setting should low if product line. If resin
/ S" f% @) ]8 I4 e. P1 L/ A& z5 e; u) I6 Rmaterial such as PPS, PA, cool very soon , Nozzle temperature should higher
, Y. k; p V; N8 fmore 10.C than the second cylinder temperature.$ W# _0 N! N0 T' T6 l% [
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.
0 k9 ], \3 U: R ]5 s& bPump turning on temperature is different depending on type of injection O5 [" K K" p8 Z
molding machine. To protect oil seal of machine it set oil temperature 4 w" z! S7 z* f& }+ @
第三節注射及熔膠(加料)工藝條件設定
. E, P2 D3 N: r5 ^* D7 ?Injection and plastic Technique parameter setting
/ _6 X7 i! g( s0 |3 a一.注射
5 G: C% u8 r1 L1 B$ Q& j: B8 MInjection9 B# T8 W( l+ z; Y2 R
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:
# ?+ S3 @; E0 T- |/ F* J7 @Injection is a step which inject melt resin material into mold. It 5 U7 G# {6 A, O5 W1 T1 W
consists of stepl,step2 ,step3,step4 and holding pressure step:
7 T" z0 _, \" d+ A1.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:
; p5 i+ N4 y0 |' U% d; i# x: b: \Step l injects usually tunnel material, Injection Volume can be
' n- L; B& S. A7 D7 Cestimated according to the weight of course it can be calculated by formula:
# j7 {4 ~+ C8 P/ A8 OL=Si=Vi/0.785Ds2
( r( d, f! r% W' R' c/ D. @L:注射行程; Si: 注射行程;
: h, Q" O2 x( n, m1 WL: injection stroke Si: injection stroke: ]4 } u p3 [ D& Q
Vi:理論注射容積; Ds:螺杆直徑;
/ b: d/ _- }( iVi: injection volume of theoretical Ds: diameter of screw: R. D6 X5 s2 H+ C+ t: _+ }* R
0.785:是Ω/4的值.
9 o! g& B6 n& e- |6 F: E8 { X0. 785: value of Ω/4.
2 V. T! b# \, {4 n* W1 \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.
3 ~( a" \9 U! z! H! R! o# cBut it cost a lot of time to produce one product if every time molding 5 C: P/ d8 H8 f# y' O5 v& B
parameter is setting by calculation.( K* e8 Q0 _3 v! 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.( S n7 {, E. H
Step 2 inject 2/3 of product. It can lower 2/3 of product according to & g* _1 d# S9 j7 T: Z
requirement of product. For example to prevent weld line. Molding speed
/ s3 \, p- W0 t* A3 u+ \5 Cand pressure on this step is the maximum of whole molding section. If
( W% C2 E8 ]# U) NMold suit the injection molding machine and mold structure reasonable 9 T9 I& G! ]5 \+ }, J" B4 a3 T; d$ e
and eject air well, pressure of this step should lower 80%. Molding speed * b; @. P, f; Q- o5 U
setting within 55-80% but it may setting 95% for especial product.5 e: e9 A" O0 E" Y9 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.
* q y( R2 T$ h4 Z5 \Step3 inject remain 1/3 of product. According to product molding speed ( c3 [# v: `+ X" g, S+ f
and pressure lower than that of step2 To prevent flash speed and
& M+ J1 Q- l0 i$ R0 R* mpressure should decrease but it can’t shot short.
3 [7 o/ Z+ ~% H! I! ?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.
6 w! o7 U$ p3 }* H& aStep4 section: Some injection machines have step5,step6 which are same
/ ]9 f5 E; l: }4 @) S! I* Ias former molding speed and pressure this step should diminish and ; t0 S( W, C2 N( d3 Q. P, U8 |
inject once more.
* k' ~# D4 S- A6 s5.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.
$ i4 Y. Q% I3 SHolding pressure step: No matter what product there is a holding
3 n/ V/ h. E2 h+ X' epressure step. Any product can’t molding a same thickness. Usually the ; z4 P; G1 G! h0 V/ Y" z q
deeper section may sink mark . To prevent this defect it should set holding
+ N9 y u0 w4 V$ c# u; b3 l( Tpressure, The injection speed of holding pressure step is slow but
) D* z- Q( B+ g; |4 dholding pressure setting within 25-80% depending on sink mark
' ?3 E6 v' c" G2 @2 ~/ v. g) @
within 40.C-60.C, If oil seal work on condition that high pressure and 5 Q- b% l+ ^' |; G+ {. Z
damaged It’s work time will be shorter, it can cause molding stable.; r% |% {& K# ~9 `
二.熔膠段工藝
3 x+ q. g0 F: Q- l+ C5 @+ x1 N: Y/ mPlastic Technique0 [1 w/ P+ X8 H# Y5 x% ~ \
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.2 f) V$ f% b+ N& h6 a( l
Plastic should lower 3 steps, because plastic is a step to add melt - p5 w# l1 f ~8 \: M
resin material to cyclinder , Higher stick of resin material ,higher screw
" @6 j: ^ d2 ]* vback pressure. Screw speed differs depending on decomposing temperature , C* m+ J/ K" s0 ]$ M
of resin material ,Higher screw speed ,Higher trim force of resin,
" \7 K9 I6 a, Y+ v: Z3 ohigher cyclinder temperature. Some resin material may decomposes so it set
# ~8 ?+ n% x! A1 F0 l9 R P5 {$ ]1 xscrew speed in mid-speed such as 45-75%, In plastic step setting screw
, l6 M* ]; B, |, q" q, I: z' h+ ?4 w/ kback pressure is very important, Higher screw back pressure ,higher ) W& } _+ h1 J9 e( r7 a
quality of product screw back pressure make resin structure order, Molding 6 J% \$ J# u) o7 V! \1 z h
product is beautiful and volume stable. But ,it maybe flow if screw
) t8 K3 e1 c* q+ F9 nback pressure too high . So all factors should be considered when using
3 J2 V O4 E% `# V+ Kscrew back pressure. 9 t L! c: e7 M; ^! x% ~4 ?
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.
/ a8 N" T/ s4 n+ {: ]4 l. qIn plastic step sucking back is very important too. Sucking back
: e& ^+ M: O- Sinclude front sucking back and back sucking back It setting sucking back to
' M* s% X6 c/ [/ t6 [& d5 Wprevent flow and line. It sets sucking back speed and pressure within : s' P; B7 D- v* C) R6 z& c. }, r
20-50% and distance within 2-5cm. TOO long distance make cyclinder $ a+ [6 `+ l; S# T, @+ U( }
reserve air and cause bubble at next molding. |
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