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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/ v& W* l: v8 U
Heating technique parameter setting
" D2 h: | s3 O, {4 ~1 A- [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.* b( s8 R1 R1 V
The proper temperature setting differs depending on type of resin
! I5 U3 y" h, P( Z/ _material, but it must be abide by a rule that temperature setting should
3 ?4 n! y- ^/ q P; r$ X A; e+ Gdiminish in step 10.C from nozzle to feeding resin material position.
3 s! V# `5 A. m/ C1 T5 U2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. 9 V0 V6 T: H' q& B
尼龍等.# n K' h3 U& o4 A# B
Nozzle temperature setting should low if product line. If resin
9 t: L% S5 K" \5 h% M5 ?' ^; c. Fmaterial such as PPS, PA, cool very soon , Nozzle temperature should higher
: _ B( ]- f4 cmore 10.C than the second cylinder temperature.
$ q& x9 l* X; D0 g R3.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.
, e9 y0 h# Q: \. ?1 ^, APump turning on temperature is different depending on type of injection $ m4 T: U4 o: N+ c% q( i$ L3 h
molding machine. To protect oil seal of machine it set oil temperature
- ?$ Y2 D% J1 O9 V" u- E8 \第三節注射及熔膠(加料)工藝條件設定
# W1 m6 F( z& D* D' E4 FInjection and plastic Technique parameter setting
% g* |7 ~2 j# L) b一.注射
0 O: X+ s/ k' c3 EInjection6 N( X) o3 \# y: 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:' \ d9 l' c& j0 ?0 }' `) ~ Y% _# [$ u
Injection is a step which inject melt resin material into mold. It 1 B# O3 N' O* r8 L2 c4 Z
consists of stepl,step2 ,step3,step4 and holding pressure step:
! s+ M9 G6 u0 _% n) Z1 [3 r1.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:- N6 k+ e, i& [/ S# p3 G
Step l injects usually tunnel material, Injection Volume can be $ d% m; N/ @# ]9 K
estimated according to the weight of course it can be calculated by formula:. ^' ^" |# }% y& e( o7 `+ z
L=Si=Vi/0.785Ds21 C% u1 ^- D% Q! e* y4 d5 I& ^* i7 r% p
L:注射行程; Si: 注射行程;1 P, f1 f8 K) p; P
L: injection stroke Si: injection stroke
+ F* V1 k/ M& IVi:理論注射容積; Ds:螺杆直徑; 8 j/ @ v7 G' a, D& i( e
Vi: injection volume of theoretical Ds: diameter of screw0 g! n2 U" }% c K" ^. L
0.785:是Ω/4的值.
3 I( E+ j0 D9 _0. 785: value of Ω/4.! j, z/ i; I% u) P2 k5 ]* J
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.. E$ P2 G$ s6 h E2 [
But it cost a lot of time to produce one product if every time molding 5 u4 N) G4 x+ G
parameter is setting by calculation.
5 U' P) U3 b: z. ~' ~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.* o; L2 m2 ]/ \* n! d2 B5 u# E$ \# Z
Step 2 inject 2/3 of product. It can lower 2/3 of product according to
2 z4 M T R( w: g# C0 ?' N8 mrequirement of product. For example to prevent weld line. Molding speed ; n3 M$ y3 @$ u5 [3 i9 R' c( b8 K
and pressure on this step is the maximum of whole molding section. If
/ x, [: Y5 M6 vMold suit the injection molding machine and mold structure reasonable & w( y) V& [7 K: v
and eject air well, pressure of this step should lower 80%. Molding speed
: [/ [ D1 A- u/ ysetting within 55-80% but it may setting 95% for especial product., R! C) c. G r3 @0 g
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., W4 E( a, Z! o, E0 W: u* t
Step3 inject remain 1/3 of product. According to product molding speed
! K; A$ y8 r0 Y6 nand pressure lower than that of step2 To prevent flash speed and
+ w: S: Z4 j( c3 ?pressure should decrease but it can’t shot short.& C, {! y; B% O; x+ ]. ]. w
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.$ y/ o4 ]$ n! ]3 o
Step4 section: Some injection machines have step5,step6 which are same - [0 f% e& J( o/ [+ h
as former molding speed and pressure this step should diminish and 6 w. j& N6 T& ?; X9 d
inject once more.
0 z1 N: l5 m( p2 M5.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.
* E' w- {0 f. e: h; L( F- C% LHolding pressure step: No matter what product there is a holding
$ w5 d6 }+ d7 N& y2 Apressure step. Any product can’t molding a same thickness. Usually the
/ u, l+ i1 g4 ` K" qdeeper section may sink mark . To prevent this defect it should set holding
- |' P9 O' _! hpressure, The injection speed of holding pressure step is slow but
; M- F+ ]9 e8 E4 ?holding pressure setting within 25-80% depending on sink mark8 {5 U% u0 ~- w: K% `& n; c, Y
3 G! t9 _6 _) Hwithin 40.C-60.C, If oil seal work on condition that high pressure and , o% `0 z& l/ w0 B1 ]8 d3 D5 T
damaged It’s work time will be shorter, it can cause molding stable.
* j, y" Y; p& T1 D; M二.熔膠段工藝; I8 E% G' o, M8 z
Plastic Technique
0 {" _: Z; L; K, L$ M3 Z/ t1.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.
; M# X1 F5 q( M: WPlastic should lower 3 steps, because plastic is a step to add melt . W- N5 b1 Y' O
resin material to cyclinder , Higher stick of resin material ,higher screw
0 Z5 |( l" p" B" K% A W- Mback pressure. Screw speed differs depending on decomposing temperature
7 W) k* a& ?! X) g: _& ]of resin material ,Higher screw speed ,Higher trim force of resin,
" A) e, u" [7 g6 c$ d1 ahigher cyclinder temperature. Some resin material may decomposes so it set
' |6 y) d( W' |! s% Zscrew speed in mid-speed such as 45-75%, In plastic step setting screw # w4 N8 `% Q( N5 `: ~
back pressure is very important, Higher screw back pressure ,higher $ V$ e1 a( ?8 E4 D
quality of product screw back pressure make resin structure order, Molding * j% }1 d0 T1 Y5 I$ a
product is beautiful and volume stable. But ,it maybe flow if screw
: m) b5 t2 g ~back pressure too high . So all factors should be considered when using + u: J2 R0 \% D
screw back pressure. * j$ J1 B8 y, O- [8 Y% t6 I
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.4 B, y- b& B) C* J9 O" V
In plastic step sucking back is very important too. Sucking back
) f* B7 q. d5 U/ U3 }6 v. Uinclude front sucking back and back sucking back It setting sucking back to % a" `- y7 e# T; [" g1 L9 l
prevent flow and line. It sets sucking back speed and pressure within 4 A- j4 P$ N5 {8 Y" r* ~" V
20-50% and distance within 2-5cm. TOO long distance make cyclinder
' d4 M/ j: C, s: Creserve air and cause bubble at next molding. |
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