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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 p M. P8 q# o- e* }# L1 N
Heating technique parameter setting- c( c3 m" ?* S( H( z
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.
: O' O0 x/ K K9 _The proper temperature setting differs depending on type of resin
# T+ k: [" {8 ?3 t4 Mmaterial, but it must be abide by a rule that temperature setting should
( a6 ^" j- l& j2 a# r- a- s* X- Kdiminish in step 10.C from nozzle to feeding resin material position. & D5 l$ t& Y M% n$ D3 g* K
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* C1 A# N0 L
尼龍等.
" \# Z6 `. r' Q* pNozzle temperature setting should low if product line. If resin
3 j& g; o* m( y# H* {material such as PPS, PA, cool very soon , Nozzle temperature should higher 9 F7 O% I7 b M
more 10.C than the second cylinder temperature.
" L+ i2 g& x! }) f3.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.- c& j" {6 X ?3 @) k N, S
Pump turning on temperature is different depending on type of injection
N% o: N) r/ n: b! Fmolding machine. To protect oil seal of machine it set oil temperature
; T+ k+ @3 G( Y第三節注射及熔膠(加料)工藝條件設定
( N& y5 l) \: B) F hInjection and plastic Technique parameter setting
0 z% _) V5 n6 Q' W/ l L4 X一.注射; S& }* U9 U# m! A
Injection. J' d/ c% W) h2 V
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:
% w- i- r& v, X8 I) T* a: w$ CInjection is a step which inject melt resin material into mold. It
# l; r( ^2 z' W8 ~consists of stepl,step2 ,step3,step4 and holding pressure step:) a- Q+ p" ]3 N) @- G
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:: k: m4 I- ` r
Step l injects usually tunnel material, Injection Volume can be , \$ E* [* { H# U( J* Q
estimated according to the weight of course it can be calculated by formula:0 A" @" t, M$ W
L=Si=Vi/0.785Ds2
+ `- g. T4 E+ g' M; k1 fL:注射行程; Si: 注射行程;' C8 U$ x$ A; i3 C0 A
L: injection stroke Si: injection stroke4 e T5 U9 S; k9 N
Vi:理論注射容積; Ds:螺杆直徑; ' g) f5 O) ~1 a0 I+ _
Vi: injection volume of theoretical Ds: diameter of screw& h6 L7 e+ X$ X. ]: o* T( ?) k2 R
0.785:是Ω/4的值. R L1 ]& V2 `( G4 C- m
0. 785: value of Ω/4.
2 a; C. n. {7 A n: w) t/ Y+ L2 m e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." M+ l! q" d8 C$ R/ @7 D
But it cost a lot of time to produce one product if every time molding 8 {; S, }) D. d1 Z& j: R$ W; ^ H
parameter is setting by calculation.4 c' \" ^: d1 U! x. r: _3 q: U
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./ K; t8 P; M- f' C* v
Step 2 inject 2/3 of product. It can lower 2/3 of product according to
E( C1 a; ] h9 F" p; rrequirement of product. For example to prevent weld line. Molding speed ( l Q5 ]# r W8 }4 t7 _* v
and pressure on this step is the maximum of whole molding section. If 9 U' A( n' R/ p5 x" R5 [1 ?
Mold suit the injection molding machine and mold structure reasonable ! u# }% N0 p8 _9 p0 D
and eject air well, pressure of this step should lower 80%. Molding speed * ]1 c3 ^7 g/ o/ f! W- {
setting within 55-80% but it may setting 95% for especial product.
3 I, Q+ `5 W8 _2 @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.
" j! {$ N9 F- V V+ A/ @- q4 FStep3 inject remain 1/3 of product. According to product molding speed 7 D, M- a' f+ N4 F) E8 U# e5 A
and pressure lower than that of step2 To prevent flash speed and
, I3 K5 D' ?' R; ]' }5 X4 \pressure should decrease but it can’t shot short.
8 _7 Y0 s4 q, }; K8 `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.
+ F6 ?9 Z; N8 V, X3 U$ cStep4 section: Some injection machines have step5,step6 which are same * @ q1 K$ `2 I8 l6 w) y9 k; z( v
as former molding speed and pressure this step should diminish and 0 }* v( M7 u9 Y4 t
inject once more.
( \, m, E5 b) U# L, C4 D L5.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.
0 c5 | K, m) Z8 X* fHolding pressure step: No matter what product there is a holding
- \9 h% z. m9 F( qpressure step. Any product can’t molding a same thickness. Usually the
% V2 T: d. O; V8 ddeeper section may sink mark . To prevent this defect it should set holding
/ ]( g6 N B- \ q8 b' I epressure, The injection speed of holding pressure step is slow but
6 T: G+ K* c5 ^ a# }holding pressure setting within 25-80% depending on sink mark% j. K' L) A0 R+ Q: F& A1 n4 B
2 E8 s- k, t! U fwithin 40.C-60.C, If oil seal work on condition that high pressure and - t+ r6 l2 E7 x* V* J) O" W
damaged It’s work time will be shorter, it can cause molding stable.
& Q# S" j9 B0 {4 b$ m二.熔膠段工藝
* D# J. g$ i9 ?Plastic Technique
2 Z& ^8 D; a& g" K, Y% k7 a- Z1.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.
( j$ F4 ~ z, c& N5 x: }/ NPlastic should lower 3 steps, because plastic is a step to add melt
j9 W( {7 ^% Zresin material to cyclinder , Higher stick of resin material ,higher screw 3 P- p# I4 U& h' o
back pressure. Screw speed differs depending on decomposing temperature
$ `7 B; k- R! X) |' u5 v+ l( Pof resin material ,Higher screw speed ,Higher trim force of resin, . V0 T; n$ H' J
higher cyclinder temperature. Some resin material may decomposes so it set ) R$ J) o7 @+ u( K4 J2 ]
screw speed in mid-speed such as 45-75%, In plastic step setting screw
; f: [/ {* l' \5 E; sback pressure is very important, Higher screw back pressure ,higher
9 i' S+ ^1 o1 H2 m. z# W( X" Qquality of product screw back pressure make resin structure order, Molding
2 E5 R5 c1 P& ~product is beautiful and volume stable. But ,it maybe flow if screw
2 z. ?7 f6 C" w6 }2 t2 E( G, Qback pressure too high . So all factors should be considered when using " ^) k! e2 f2 a
screw back pressure. ' i& Y3 u. A5 V* \
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.2 n! p+ h( S$ _3 Y# z# k
In plastic step sucking back is very important too. Sucking back
/ X' x! f* K7 I: N1 ^7 jinclude front sucking back and back sucking back It setting sucking back to 9 m3 E( ?) U$ |! b; T
prevent flow and line. It sets sucking back speed and pressure within 8 f2 A: ^# K( p% G' o" J# }
20-50% and distance within 2-5cm. TOO long distance make cyclinder " u) h/ x9 q/ e- R/ h
reserve air and cause bubble at next molding. |
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