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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
; R3 I( h% d4 S4 ^. }. NHeating technique parameter setting3 }6 Z) B& _9 h. P8 r4 u4 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.
, n: F) F U; C& l i" {1 ]7 RThe proper temperature setting differs depending on type of resin 2 F# [! [: L/ c2 H! R$ B
material, but it must be abide by a rule that temperature setting should & Y0 E; S+ Y0 _) e3 E
diminish in step 10.C from nozzle to feeding resin material position. b. a2 @+ B( _# i; O
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. $ m/ E6 l5 h$ A1 s0 a
尼龍等.! q( c# Z. B2 p
Nozzle temperature setting should low if product line. If resin # t1 Z( h$ C+ f' j
material such as PPS, PA, cool very soon , Nozzle temperature should higher
& \& Z* \) Z7 q: |( Zmore 10.C than the second cylinder temperature., _) ?1 [: Z. a! J9 ^1 m
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.% W& h- L5 C% D/ u; X! N9 c ]
Pump turning on temperature is different depending on type of injection 6 G+ ?# O" r! r" C3 \
molding machine. To protect oil seal of machine it set oil temperature / R& [; u. H( f2 q0 Y
第三節注射及熔膠(加料)工藝條件設定& b* \; C- w- r0 g* w: x0 ^
Injection and plastic Technique parameter setting
. h5 j( D# Y; R8 E$ z; D. b4 {; K一.注射
, u1 v" R4 x qInjection
9 Y1 ^1 M' P3 |! h* ^0 j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:
8 H. B' G4 g1 d6 lInjection is a step which inject melt resin material into mold. It
5 I7 D- s; i* c, z% o' Wconsists of stepl,step2 ,step3,step4 and holding pressure step:
2 Z3 s4 I+ ` a. m- M( G1.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 t) L. l4 f6 ?! RStep l injects usually tunnel material, Injection Volume can be
7 M; ~6 g$ X9 ~* uestimated according to the weight of course it can be calculated by formula:0 F$ a* b& R8 I
L=Si=Vi/0.785Ds2
$ x8 z2 R( k# T3 zL:注射行程; Si: 注射行程;
" P1 t' w( D. s6 j. g' I! T3 ^# UL: injection stroke Si: injection stroke `9 T$ Y! T- w: k
Vi:理論注射容積; Ds:螺杆直徑;
8 E9 P6 J' x5 ~( i" [0 L6 ?7 Y% cVi: injection volume of theoretical Ds: diameter of screw
3 u& y+ d% D3 b# R( o: m0.785:是Ω/4的值.$ ?7 Y2 E- c! D! g" B* P
0. 785: value of Ω/4.
0 M% ?9 X( e9 v/ 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./ Z5 z& \) K$ o
But it cost a lot of time to produce one product if every time molding
7 I# ?7 U+ g0 J& B# m% p, v" uparameter is setting by calculation.3 I2 Z0 o) w2 L4 D( ~2 N; m, z+ r* v
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.
% k6 N+ S7 x& u& f! U9 i; W+ O* wStep 2 inject 2/3 of product. It can lower 2/3 of product according to
( f9 X4 K( x& \) {requirement of product. For example to prevent weld line. Molding speed
7 ?9 ^( A. n8 w6 Xand pressure on this step is the maximum of whole molding section. If 1 x/ b* b Z8 P- F& \- T' v. W
Mold suit the injection molding machine and mold structure reasonable ' Z8 \* W. I! n9 B. R5 N
and eject air well, pressure of this step should lower 80%. Molding speed ' ?; {. j. K# Q( Q# y
setting within 55-80% but it may setting 95% for especial product.
- I! F, o k( _# `. ?* C& o/ t3.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.
9 m/ y; w# l. y+ F& c" JStep3 inject remain 1/3 of product. According to product molding speed
4 R* x7 H, ^& tand pressure lower than that of step2 To prevent flash speed and 0 K, O$ S9 L3 p+ g
pressure should decrease but it can’t shot short.
$ t! {% _- z- A5 F4.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.
) N9 Y9 R% z2 T$ H+ [$ g" zStep4 section: Some injection machines have step5,step6 which are same
; v4 Q. T/ f" L4 D, xas former molding speed and pressure this step should diminish and
0 u" |6 b2 O, ]" ?/ Sinject once more.$ M' z9 _# B3 R' e) o4 o4 G5 C
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. n0 Q' ?. t+ ?3 V. } Y
Holding pressure step: No matter what product there is a holding
3 n6 M! }* [. k! spressure step. Any product can’t molding a same thickness. Usually the
% Z H1 }1 i4 Zdeeper section may sink mark . To prevent this defect it should set holding 4 S+ O; L1 V/ ~) x- f
pressure, The injection speed of holding pressure step is slow but 7 l0 a$ z$ U+ [, p. E0 p" p5 l7 [
holding pressure setting within 25-80% depending on sink mark
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1 x9 f" S' h8 V* }; ?within 40.C-60.C, If oil seal work on condition that high pressure and
+ e, Q3 K3 w/ D6 cdamaged It’s work time will be shorter, it can cause molding stable.; @! V) q& p: w" ?
二.熔膠段工藝
% R2 y5 x, q6 \) b/ U9 h6 bPlastic Technique" f4 P. v E, z% k- |$ ?. E) B
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." T9 |; n# }3 ]+ P8 a' c
Plastic should lower 3 steps, because plastic is a step to add melt
( Q) ]1 K4 @' ]- f; y# wresin material to cyclinder , Higher stick of resin material ,higher screw , l f- |1 X8 M
back pressure. Screw speed differs depending on decomposing temperature . P3 J- l& v+ F M& M4 q" ]3 K
of resin material ,Higher screw speed ,Higher trim force of resin,
2 t; J; T( M: j5 ahigher cyclinder temperature. Some resin material may decomposes so it set # X0 i" |3 _2 j% V% P6 L
screw speed in mid-speed such as 45-75%, In plastic step setting screw
% d! T" w- Z" y- }back pressure is very important, Higher screw back pressure ,higher 0 z3 U; s/ I& ^/ R" z( d
quality of product screw back pressure make resin structure order, Molding ( Z( X7 ~7 g1 q+ n! r- h/ m
product is beautiful and volume stable. But ,it maybe flow if screw 2 a, q" f. F- P# i8 S
back pressure too high . So all factors should be considered when using
! q- ^1 H! q7 m( nscrew back pressure.
& n; V( Z; w! [* q( 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." \0 R, Y" S5 F
In plastic step sucking back is very important too. Sucking back
) x. B9 _6 c, h4 i' b5 d7 o" @8 ginclude front sucking back and back sucking back It setting sucking back to " c2 ~1 N! E1 B: T5 i& i( q7 Y
prevent flow and line. It sets sucking back speed and pressure within
2 t/ w% W' H$ s8 T20-50% and distance within 2-5cm. TOO long distance make cyclinder
+ ] d; }. y) `( @# q3 h L# ?0 Ureserve air and cause bubble at next molding. |
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