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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- w9 U; n1 Y9 v) I/ {/ Y$ k
Heating technique parameter setting
/ n' U8 O3 w+ O& L1.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( u8 T" t# I; d$ i! y" oThe proper temperature setting differs depending on type of resin / u; ~- w5 W( I1 L1 E
material, but it must be abide by a rule that temperature setting should
9 l2 }5 N/ U# t( w5 u$ g% Pdiminish in step 10.C from nozzle to feeding resin material position. 5 o0 i, b' e. |& D9 T
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.
) s- a' N& A# w- F8 f% V, \尼龍等.$ R! f5 g8 ?" ~
Nozzle temperature setting should low if product line. If resin
+ y; O! ~/ N- T% Vmaterial such as PPS, PA, cool very soon , Nozzle temperature should higher
, v, s1 p- e( ?) T3 }" imore 10.C than the second cylinder temperature.
* T* s. s( H& d0 Q, r8 y6 ^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.- K/ ~& X. E% a/ }
Pump turning on temperature is different depending on type of injection - F1 l9 A$ ~9 n/ Q) O3 b+ a: V
molding machine. To protect oil seal of machine it set oil temperature 3 U0 J) u* J" r9 g% c% s- X
第三節注射及熔膠(加料)工藝條件設定
" Q+ J+ c" \5 X; i3 @% _Injection and plastic Technique parameter setting: Z8 y( N9 ~2 r; }- }" [( [7 x7 {
一.注射/ S2 n6 [' T2 a8 I% \3 b
Injection
m8 Y8 S0 ?# R+ q) 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:) l0 u5 i5 d) i0 S3 t* N
Injection is a step which inject melt resin material into mold. It * V, i. B% y% s' m6 S
consists of stepl,step2 ,step3,step4 and holding pressure step:
# s% Q& Z; y1 J; z1.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:7 J7 `, R# M/ K9 @
Step l injects usually tunnel material, Injection Volume can be
! \, |7 ^- i; a. `0 B' lestimated according to the weight of course it can be calculated by formula:
6 A9 u# C2 |: B2 A5 {6 m' L9 |- ]L=Si=Vi/0.785Ds2
2 B6 h/ }; u& {& @3 ?L:注射行程; Si: 注射行程;! H5 `2 T; s1 S" o
L: injection stroke Si: injection stroke
5 }. A( t% s/ S% e3 a7 oVi:理論注射容積; Ds:螺杆直徑; # Q1 M! f5 ?% t, K( M
Vi: injection volume of theoretical Ds: diameter of screw1 p" w/ h/ c( S9 s' u' R. ?" d
0.785:是Ω/4的值.3 J$ U0 N+ {* ^) S4 u
0. 785: value of Ω/4.
+ L& |4 \0 d- Q, z9 P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.
t9 x& g: g. Z9 t$ NBut it cost a lot of time to produce one product if every time molding ! v# ]. P* |0 b: Y5 h' i" }) C
parameter is setting by calculation.
! s" e; \6 d8 U+ L( ?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.0 {8 A8 D! Q! G. Y
Step 2 inject 2/3 of product. It can lower 2/3 of product according to * R+ ^4 [0 v2 L# `% y
requirement of product. For example to prevent weld line. Molding speed
5 Z! Y2 {; E2 t$ |and pressure on this step is the maximum of whole molding section. If 1 e, Y( K9 [- T! d& g8 e
Mold suit the injection molding machine and mold structure reasonable
) ~/ c6 b8 M4 Hand eject air well, pressure of this step should lower 80%. Molding speed
0 v$ y: B6 L3 w5 [setting within 55-80% but it may setting 95% for especial product.3 o' }8 H7 |5 Q' K6 a6 [" t- z
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. x& ^: [$ {" B+ W5 S" c
Step3 inject remain 1/3 of product. According to product molding speed " V/ V: p6 x. n) E% L! ~( R. t
and pressure lower than that of step2 To prevent flash speed and
$ d+ s, Z6 u9 h: ?# B6 upressure should decrease but it can’t shot short.
0 s* g1 @' a; K% \% T5 p4.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. P$ ?0 h' h n3 R
Step4 section: Some injection machines have step5,step6 which are same + f; k W9 B9 L/ ?+ v8 q% t" I" H
as former molding speed and pressure this step should diminish and
Q+ `7 R' @ W s& O! {5 Dinject once more.
+ ]) U* H1 f& ]( n! J6 J5.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." K& \1 c6 e$ T5 U: T7 v
Holding pressure step: No matter what product there is a holding % q5 N4 s) g, B
pressure step. Any product can’t molding a same thickness. Usually the z; `& R' i! k7 x. r. V" x
deeper section may sink mark . To prevent this defect it should set holding + F" |+ R' K( E2 \! z4 B- ^
pressure, The injection speed of holding pressure step is slow but 8 I# N; f/ d7 |
holding pressure setting within 25-80% depending on sink mark4 V* }, }4 @+ @5 A
: o$ l- [% P8 c5 Y+ W& K" v$ s
within 40.C-60.C, If oil seal work on condition that high pressure and - L% e8 Q# K/ x- d5 u
damaged It’s work time will be shorter, it can cause molding stable.) J, E0 q8 W2 @7 i4 M# t8 o
二.熔膠段工藝
) Y/ g# a/ {" [( |) [* l9 aPlastic Technique0 ?! O/ A) `" [) H0 N! D( l/ @" c% j- R
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.
! z" z. K4 }% T+ ~Plastic should lower 3 steps, because plastic is a step to add melt
N! `2 N* I" \* }resin material to cyclinder , Higher stick of resin material ,higher screw 0 n& t% O' U( f; |
back pressure. Screw speed differs depending on decomposing temperature . t6 }' f" x- d: d
of resin material ,Higher screw speed ,Higher trim force of resin,
: \/ s- K: q1 r: J* xhigher cyclinder temperature. Some resin material may decomposes so it set
" O1 A; v7 Y. Y/ `2 o$ n6 vscrew speed in mid-speed such as 45-75%, In plastic step setting screw
. @( e( F* |& X& B& ~& X2 z. _back pressure is very important, Higher screw back pressure ,higher
1 Q& B+ j& N- Fquality of product screw back pressure make resin structure order, Molding
# ?: b L$ P- _5 D/ V l0 a/ K/ Y( Aproduct is beautiful and volume stable. But ,it maybe flow if screw $ `7 b! x. N! ^
back pressure too high . So all factors should be considered when using
+ ]& A& _9 A0 ?screw back pressure.
3 w2 n$ k( n; ^- a& e" a2.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.
1 }7 B6 [6 {4 A. _+ rIn plastic step sucking back is very important too. Sucking back 1 Z' a9 `3 R$ g D3 j
include front sucking back and back sucking back It setting sucking back to . g0 }! H, n4 I; T& f I- I6 n
prevent flow and line. It sets sucking back speed and pressure within 5 z& M0 L& _0 m4 u2 [3 s
20-50% and distance within 2-5cm. TOO long distance make cyclinder
, O' V4 z4 t% N" r) yreserve air and cause bubble at next molding. |
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