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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
2 j! d4 I( [9 `/ d! S- x+ WHeating technique parameter setting) C1 e! ^9 t' c9 T; X
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.. S" s' _8 @+ o2 R; N
The proper temperature setting differs depending on type of resin ' ?9 n. S& i* _
material, but it must be abide by a rule that temperature setting should 9 x9 ?$ b6 T3 u% |& }/ A5 @3 h' C
diminish in step 10.C from nozzle to feeding resin material position.
0 M. ^" E5 A$ u5 H9 B& E# j2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.
% U3 E5 [ @8 v$ ]# {尼龍等.
0 p$ x5 ~% \2 P& k+ T& B* J2 lNozzle temperature setting should low if product line. If resin 4 _$ N9 P' ~- q3 M4 `
material such as PPS, PA, cool very soon , Nozzle temperature should higher
, B! D2 [/ c% w* M* Pmore 10.C than the second cylinder temperature.# o/ ^+ C+ m6 W3 [- T; Q A
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.+ ~5 m: V2 c8 R
Pump turning on temperature is different depending on type of injection
) \) x7 c2 q7 V2 T8 cmolding machine. To protect oil seal of machine it set oil temperature
! V0 W6 _( R" x- Q% [第三節注射及熔膠(加料)工藝條件設定
) {, G& f; y; \! G3 ^$ {Injection and plastic Technique parameter setting+ B& k( ~$ Y6 P0 K* n
一.注射
, D; j9 ~- W; K1 f; \: H& k% rInjection
. L0 a3 G2 N+ f% h1 e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: _" w o4 y Y* v3 h& R5 U
Injection is a step which inject melt resin material into mold. It
2 E: p$ Y1 X+ J$ ]4 @consists of stepl,step2 ,step3,step4 and holding pressure step: l- N" V3 U- S9 @ U4 u, M
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:
/ ]0 G3 e: |! B+ ], w$ w' HStep l injects usually tunnel material, Injection Volume can be 7 c4 q. D# u; R; J1 h+ P+ @
estimated according to the weight of course it can be calculated by formula:4 o; W. k/ i. E# l" j2 {7 T
L=Si=Vi/0.785Ds2
7 F( M. l% P, V/ n0 yL:注射行程; Si: 注射行程;# J7 ]. e$ X: ~8 ]8 W- ]6 G! r/ }6 m
L: injection stroke Si: injection stroke5 m+ u4 C) H, Y4 y9 Y2 u
Vi:理論注射容積; Ds:螺杆直徑; & A- p6 m$ }+ @. k6 L9 B6 f
Vi: injection volume of theoretical Ds: diameter of screw4 p9 u G- l3 m4 j+ p! B) s T. P
0.785:是Ω/4的值.
$ y' E M. @! Q2 P4 S0. 785: value of Ω/4.3 @8 D" A. ~( H: I
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.
' a3 U, G5 @3 I; @1 SBut it cost a lot of time to produce one product if every time molding
6 |/ N# S, K+ Sparameter is setting by calculation.5 X0 Z) h% m! r, r5 \& A8 @
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. N6 g2 K7 A! _1 n
Step 2 inject 2/3 of product. It can lower 2/3 of product according to 1 Y/ M* i2 s5 R* U: u4 p
requirement of product. For example to prevent weld line. Molding speed
, D( R5 Y( z5 x8 O/ vand pressure on this step is the maximum of whole molding section. If
7 x+ k+ [2 @" I, R" C' b- J pMold suit the injection molding machine and mold structure reasonable
; S6 h2 K6 s5 c. w" Z3 {and eject air well, pressure of this step should lower 80%. Molding speed ) e1 s* T* s& Q$ q8 q5 M G
setting within 55-80% but it may setting 95% for especial product.; J5 e0 C* y) _
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.
7 ^/ ^; w) u6 K7 W; TStep3 inject remain 1/3 of product. According to product molding speed $ v' s5 t* e" q8 p: _+ Z' E
and pressure lower than that of step2 To prevent flash speed and 3 H1 w8 F% S6 N$ B, n# O
pressure should decrease but it can’t shot short.) {6 ^0 Y m- x8 k
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.* ?( [# e. c: U. k
Step4 section: Some injection machines have step5,step6 which are same $ \2 S4 R* x! q- k3 u
as former molding speed and pressure this step should diminish and
( ?! j( y5 c7 I7 o( p! }/ V8 Linject once more.
5 M [ E5 D9 C$ c5 g6 G* k5.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.
6 ~$ T! u5 P3 B% f# gHolding pressure step: No matter what product there is a holding
9 s8 q4 u8 A, ~& r5 Mpressure step. Any product can’t molding a same thickness. Usually the % d4 P7 q3 ?8 j
deeper section may sink mark . To prevent this defect it should set holding 0 d* x* [; O% c5 C
pressure, The injection speed of holding pressure step is slow but ( N& S( d: \2 }
holding pressure setting within 25-80% depending on sink mark
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- L- M( P$ O! S- O" i/ T8 Zwithin 40.C-60.C, If oil seal work on condition that high pressure and 0 f) Q1 s6 s6 K5 h
damaged It’s work time will be shorter, it can cause molding stable.
' `, y& q% O: n: w N4 s1 Q3 A二.熔膠段工藝
Z* D c! } l* mPlastic Technique3 A6 m) Q- L7 m6 p5 u% x8 Y9 z
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./ e) ]( Y% E7 x" V& U
Plastic should lower 3 steps, because plastic is a step to add melt R$ _* o+ P2 b6 g1 t0 q& h1 X7 E
resin material to cyclinder , Higher stick of resin material ,higher screw
f/ Q& }- X) t/ P4 l$ ?) P0 aback pressure. Screw speed differs depending on decomposing temperature 2 Q0 h% G0 M( A6 S, c U0 n0 d
of resin material ,Higher screw speed ,Higher trim force of resin, * |% p$ w1 Q: @, l. G* M+ D& C0 `
higher cyclinder temperature. Some resin material may decomposes so it set
5 t: q4 g: g& t# {2 c! c$ Wscrew speed in mid-speed such as 45-75%, In plastic step setting screw
0 R& Y( {7 m+ Z c9 s: E( ^: Tback pressure is very important, Higher screw back pressure ,higher 4 e% p: f0 \! G1 S+ }* Q
quality of product screw back pressure make resin structure order, Molding
/ x$ ~+ m. e4 k" P6 L2 N9 n0 ~product is beautiful and volume stable. But ,it maybe flow if screw - h& B z A( H. M% v
back pressure too high . So all factors should be considered when using 4 @$ h7 \1 ~% T8 Y& a
screw back pressure.
1 T! G: S' P9 O8 |( o0 x/ E2.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.
( S, M! B2 M* rIn plastic step sucking back is very important too. Sucking back
8 a- z2 V5 r- n8 Q$ [include front sucking back and back sucking back It setting sucking back to 4 [9 P( g' A, Z/ z2 {: q- ?
prevent flow and line. It sets sucking back speed and pressure within
/ ?9 ]5 s+ `. z- i20-50% and distance within 2-5cm. TOO long distance make cyclinder 5 J& v! h0 I" q
reserve air and cause bubble at next molding. |
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