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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) X1 O) j4 {' i% b9 G1 T
Heating technique parameter setting
0 `: @" z, M* [2 y+ W( e; Z1.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.
; y. F. D( C4 \8 t4 OThe proper temperature setting differs depending on type of resin
2 i% G- R& Y: w- Pmaterial, but it must be abide by a rule that temperature setting should ' `9 S) ?5 x) O, u' [: [8 [
diminish in step 10.C from nozzle to feeding resin material position. 2 _: r9 _; d, G/ y* c4 v. L
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. ! q& c$ g/ \$ x
尼龍等. R: J3 e3 p+ Y; n4 s2 R
Nozzle temperature setting should low if product line. If resin 9 b7 x$ H/ e1 h
material such as PPS, PA, cool very soon , Nozzle temperature should higher
' E. t0 N) z: ]3 b! }6 {more 10.C than the second cylinder temperature.. ~! F) I+ p: E8 {$ Z
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.
/ |3 D2 W9 D6 V( ~$ PPump turning on temperature is different depending on type of injection
2 L" P7 d2 u% L" s' j6 S' Q3 @molding machine. To protect oil seal of machine it set oil temperature
# p* w4 D0 C3 Q0 s7 [+ G5 M3 ?第三節注射及熔膠(加料)工藝條件設定; j. h6 ~! K- \& M
Injection and plastic Technique parameter setting
8 ^2 k6 w# B' Y* a一.注射
" D( M6 p6 R. f7 gInjection* }# e8 k! D& Q! v# x. u% 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:( R) O! M" @8 _: L
Injection is a step which inject melt resin material into mold. It ( V% h8 o! p8 b
consists of stepl,step2 ,step3,step4 and holding pressure step:# `0 ^# N% }) P3 z" d5 s: U; L
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:
% {8 o3 e3 Q+ ]; cStep l injects usually tunnel material, Injection Volume can be
6 J7 r6 l5 S+ h+ @8 A6 gestimated according to the weight of course it can be calculated by formula:
3 V7 U) N2 N4 ^" xL=Si=Vi/0.785Ds2. J7 N% j; n0 h( ?( {
L:注射行程; Si: 注射行程;9 a+ l1 d* }3 X! n* l0 i- J
L: injection stroke Si: injection stroke
7 U4 a* \6 O& Y; W8 QVi:理論注射容積; Ds:螺杆直徑; " V+ ?6 x" M& T5 @
Vi: injection volume of theoretical Ds: diameter of screw
$ q! Z/ l+ P* \8 x0.785:是Ω/4的值.
" P8 m9 E% L7 ]. m# O6 }' g- U0. 785: value of Ω/4.
& Y6 J% E# u/ s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.
0 Z: x$ n4 Y! o& ^But it cost a lot of time to produce one product if every time molding
: ^4 _; m* w* n! y6 W9 W6 w3 oparameter is setting by calculation. \3 T; J O) h' R6 u! m: D
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.: c# ~: C- U, c( P1 R
Step 2 inject 2/3 of product. It can lower 2/3 of product according to
4 j* X! w2 K, G9 X0 |1 C4 c6 jrequirement of product. For example to prevent weld line. Molding speed
1 d' d2 C! z5 D& c2 h8 @and pressure on this step is the maximum of whole molding section. If + Q- d/ N4 K9 N1 c5 g% r$ b
Mold suit the injection molding machine and mold structure reasonable : x: B8 z: K+ [$ Z0 g5 a
and eject air well, pressure of this step should lower 80%. Molding speed
: I7 T _9 ^+ V4 c' C# A# s$ H3 y* fsetting within 55-80% but it may setting 95% for especial product.% M @! f& }7 n8 l6 h5 d8 O
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 L8 d0 q, ~* R! hStep3 inject remain 1/3 of product. According to product molding speed 6 f' R5 z! d% U. p; }
and pressure lower than that of step2 To prevent flash speed and 5 D0 V: Q+ k/ ?0 x. ^2 x9 O- M
pressure should decrease but it can’t shot short.4 n$ l. p5 k3 V8 G+ {* J+ Y/ b5 ]
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.1 z* M9 X" B1 `2 v$ e
Step4 section: Some injection machines have step5,step6 which are same 1 m( ?2 a( j4 |' m" z
as former molding speed and pressure this step should diminish and
) ]) Q/ j6 F% | uinject once more.
# p: m$ y9 E Q5.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. p" U+ t' C5 p3 s* K4 m
Holding pressure step: No matter what product there is a holding " H- I5 F2 ~" C0 X4 ^+ h
pressure step. Any product can’t molding a same thickness. Usually the 8 Q( }: r% Z, y1 N9 I; Q
deeper section may sink mark . To prevent this defect it should set holding
5 @3 _$ T) `4 R" P0 l2 @( ipressure, The injection speed of holding pressure step is slow but 6 q3 p+ T& l- v8 l) B' b
holding pressure setting within 25-80% depending on sink mark' y" m- q0 j: d$ y8 `5 V5 e: n- b- O
" C, G" F H' u: Nwithin 40.C-60.C, If oil seal work on condition that high pressure and
8 `: d5 l' e4 Ndamaged It’s work time will be shorter, it can cause molding stable.. V( f; P7 Z/ `; z$ Z! y
二.熔膠段工藝
& R4 M6 ^/ ^( ~4 {$ O' | o+ MPlastic Technique7 j# H3 Z/ N- h9 |3 V S) }
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.
4 i* U. M* { W5 uPlastic should lower 3 steps, because plastic is a step to add melt & x. q. ^5 c( p6 v3 x$ N
resin material to cyclinder , Higher stick of resin material ,higher screw & }# {4 ^* c% s8 Z! R3 L
back pressure. Screw speed differs depending on decomposing temperature
* e6 h, \& Y7 x+ {; n: k7 Y( C6 wof resin material ,Higher screw speed ,Higher trim force of resin, # w& h# N/ n4 r i' o% f* U
higher cyclinder temperature. Some resin material may decomposes so it set
% Y& v+ _7 r. s9 E- Zscrew speed in mid-speed such as 45-75%, In plastic step setting screw
% N5 f( {/ T5 j8 F$ pback pressure is very important, Higher screw back pressure ,higher 5 ]' A0 F6 F, Q
quality of product screw back pressure make resin structure order, Molding
+ v9 _$ R% w* ?7 C4 L$ o2 C2 Wproduct is beautiful and volume stable. But ,it maybe flow if screw m9 |2 ^. y. f2 o) t u l
back pressure too high . So all factors should be considered when using 7 U& ~- w) W+ N# x4 f
screw back pressure.
: I+ b3 h6 r9 t N( y o4 p2.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.
) i9 v7 z( B* i" C9 Y+ n5 |! bIn plastic step sucking back is very important too. Sucking back
0 H6 [! b" j# o" z: Minclude front sucking back and back sucking back It setting sucking back to
, q' v8 {- G3 j& n" q( g- bprevent flow and line. It sets sucking back speed and pressure within
5 L8 @' N" j/ \, g8 q7 I20-50% and distance within 2-5cm. TOO long distance make cyclinder 4 v7 k# g& \3 J/ f1 t
reserve air and cause bubble at next molding. |
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