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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 F7 J( A# @1 c& A: c0 F
Heating technique parameter setting
3 F8 l2 ~5 S. T8 ^, E2 k1.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.
2 q, F/ w: J( n7 VThe proper temperature setting differs depending on type of resin ' F6 ~; p3 C7 P+ _7 `( o7 `$ A
material, but it must be abide by a rule that temperature setting should
" S+ ^! H# a% m. j6 ldiminish in step 10.C from nozzle to feeding resin material position. " t- U: a& w' Y+ a: q
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.
) J' g3 H: n. e3 }8 q( h尼龍等.
/ E6 k" k! t& H! v7 RNozzle temperature setting should low if product line. If resin
8 L5 \+ D5 Y; D7 h+ ?# Cmaterial such as PPS, PA, cool very soon , Nozzle temperature should higher # j: R$ n0 W* y& Y. L
more 10.C than the second cylinder temperature.* `0 o' F- G$ X) h& T" j; [
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.
# i" _: w6 H, x6 K6 B" d5 fPump turning on temperature is different depending on type of injection
3 b( s+ j6 ?6 G3 h2 Y/ s6 r% i. P, ^molding machine. To protect oil seal of machine it set oil temperature
, v+ i* N* ]- C/ n第三節注射及熔膠(加料)工藝條件設定
% ^) O" D" h1 w, d- s2 ~# J! O; R, SInjection and plastic Technique parameter setting( r2 e4 x1 T" A4 Z) R% x$ w
一.注射0 {6 E( Q4 X' Q% a9 g1 E
Injection: o* a% a9 X3 a) A, f
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:. i% d: G$ ? j: T0 _
Injection is a step which inject melt resin material into mold. It / p; C3 X5 p5 `) ]
consists of stepl,step2 ,step3,step4 and holding pressure step:3 M2 ]0 S4 x6 f2 d. B8 L8 a, _0 h8 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:
) F: S0 @$ l$ k& e8 u PStep l injects usually tunnel material, Injection Volume can be
4 v: }5 ~" L4 k1 \# x- r; [! mestimated according to the weight of course it can be calculated by formula:
# B9 ?1 [ a& Y; m; t% g' WL=Si=Vi/0.785Ds2
$ b- f6 {4 t( H* l8 CL:注射行程; Si: 注射行程;0 B, i6 s. u* U& A& t H
L: injection stroke Si: injection stroke
* B% \9 G$ B0 i( ?& ^/ K( e ?2 l( VVi:理論注射容積; Ds:螺杆直徑; 4 [ t# k9 n5 @
Vi: injection volume of theoretical Ds: diameter of screw; r! Q+ V2 M9 E/ ~5 X1 b! l
0.785:是Ω/4的值.3 B* t- x* {% y( T
0. 785: value of Ω/4.
6 @7 g4 E7 F+ `* _" W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.
, q" B0 x! [; a7 A# A& BBut it cost a lot of time to produce one product if every time molding
9 t7 ^2 B1 h1 c+ t+ A" c8 fparameter is setting by calculation.
: o- S. E8 y9 L5 m2.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.
$ {$ z* ~2 Z V* LStep 2 inject 2/3 of product. It can lower 2/3 of product according to
1 y5 y, l: y+ Q2 |& F: F5 vrequirement of product. For example to prevent weld line. Molding speed
5 B, s' k7 y- t2 C0 n5 R+ ^and pressure on this step is the maximum of whole molding section. If b% t9 _' ~. a7 S9 m1 q. S/ ^1 R* W
Mold suit the injection molding machine and mold structure reasonable 9 P' h6 A9 g% p- f1 L& Q- q8 l
and eject air well, pressure of this step should lower 80%. Molding speed
( H& y4 U, n, w T, Usetting within 55-80% but it may setting 95% for especial product.
; u, Z; ]6 R; f I7 A3.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.- O" ~( \, K9 Z; \$ E: G( Q' s
Step3 inject remain 1/3 of product. According to product molding speed $ ~. W: s. n. K/ j' N
and pressure lower than that of step2 To prevent flash speed and
4 r/ h5 w2 o% H# R1 epressure should decrease but it can’t shot short./ L; h; L9 b2 p8 R
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.
0 W- x' n; E: t- e! c4 Y/ Q2 }Step4 section: Some injection machines have step5,step6 which are same 0 w. |- o0 X8 v& C* y- w
as former molding speed and pressure this step should diminish and
; j+ s' i" s6 Y. p+ pinject once more.1 X# c7 A7 a" |- S5 Q9 ]; D% P" A" [
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.
& b, U! ? U& D M$ T+ `Holding pressure step: No matter what product there is a holding ' s) s$ d q* }" @% i
pressure step. Any product can’t molding a same thickness. Usually the 8 X- n9 M, `* {( l$ L8 e
deeper section may sink mark . To prevent this defect it should set holding
) g% A* I" q: G6 w3 Upressure, The injection speed of holding pressure step is slow but
* x% P+ ~& f; h4 `7 sholding pressure setting within 25-80% depending on sink mark3 d% p0 Q6 q& C$ y; C4 X
2 z' R8 V4 }! t% p4 s
within 40.C-60.C, If oil seal work on condition that high pressure and # a! `$ J( P' R8 e" P
damaged It’s work time will be shorter, it can cause molding stable.1 Z8 q6 n) C9 }8 ^) a
二.熔膠段工藝. f! J# n2 ]9 g9 J' u! \! l$ T, a
Plastic Technique
# D g8 e9 Y6 A( {# V/ X1.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.
" F2 k2 C1 X- t( Z1 K# R/ `Plastic should lower 3 steps, because plastic is a step to add melt
& M' Q% ~1 ?( R, _8 v# D% s' zresin material to cyclinder , Higher stick of resin material ,higher screw ( o/ o6 p8 c0 d: f6 S6 D
back pressure. Screw speed differs depending on decomposing temperature 6 X- K' D4 e7 Y' W# D: f6 H0 j
of resin material ,Higher screw speed ,Higher trim force of resin,
4 {( B. z$ O. Whigher cyclinder temperature. Some resin material may decomposes so it set / J3 q; ~0 r9 F* p
screw speed in mid-speed such as 45-75%, In plastic step setting screw
% l0 Z7 x- E2 p* u& t8 ], p# Gback pressure is very important, Higher screw back pressure ,higher % Y6 P. P0 u- Z6 N% \0 e) m
quality of product screw back pressure make resin structure order, Molding . l) e, L m7 a. k) M. T- P
product is beautiful and volume stable. But ,it maybe flow if screw 9 v5 `# z+ L- c, n- ~' j% r9 t
back pressure too high . So all factors should be considered when using
. W, M( h; @4 a: E2 s% }% n$ fscrew back pressure. 6 P+ ]- n6 x! D( }& K, U
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.1 @/ Q6 V5 q5 @; _+ m" N: a
In plastic step sucking back is very important too. Sucking back 1 e9 i8 _1 D$ _$ X6 O( X
include front sucking back and back sucking back It setting sucking back to 8 O* V% X/ @4 c. L# G$ J
prevent flow and line. It sets sucking back speed and pressure within
/ c7 {5 N( h# I; W20-50% and distance within 2-5cm. TOO long distance make cyclinder
q& q4 k; M. m: a' V9 J) d, Hreserve air and cause bubble at next molding. |
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