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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
4 I5 o" G2 O1 K- |+ jHeating technique parameter setting
' A& M9 n/ \9 \/ j* T5 m4 {2 n1.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.
6 ~ j. O) B4 ?5 j: q) SThe proper temperature setting differs depending on type of resin
0 _7 D( } D: u. o, k9 J* fmaterial, but it must be abide by a rule that temperature setting should
0 {/ f0 K$ O% {0 ^& `% n0 Idiminish in step 10.C from nozzle to feeding resin material position.
/ T' T F' m* W' a, d: D! D2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.
. u' J# G2 u, L. a! K尼龍等.( j9 K E" ^; P% I" c& w/ R
Nozzle temperature setting should low if product line. If resin " s* u- I, G$ q+ j- T3 S
material such as PPS, PA, cool very soon , Nozzle temperature should higher 7 W) q6 [, s$ h! b5 I4 t6 E( ]/ M
more 10.C than the second cylinder temperature.% R5 A0 N+ ]+ l& [% U2 W
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.$ j* z; R% K7 C! ] I* B
Pump turning on temperature is different depending on type of injection * B0 V3 k c L: X [
molding machine. To protect oil seal of machine it set oil temperature
' p) V* _+ r# h( ~第三節注射及熔膠(加料)工藝條件設定, F, c- F& [2 V$ H6 I$ z
Injection and plastic Technique parameter setting
0 s) N- \( O& Y: ~一.注射: ?% |1 h; L1 j2 i
Injection
& w) U Y0 u# ^7 ^3 x6 ]1 M8 b4 i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:
# f: v9 }# }' Q' O& DInjection is a step which inject melt resin material into mold. It 9 F; ~% h' T6 J9 J
consists of stepl,step2 ,step3,step4 and holding pressure step:; o- [- |2 i6 d) p- L w
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:
. M# R2 G( t* R, i7 `. ^Step l injects usually tunnel material, Injection Volume can be
3 ^2 _7 q5 B% h' [ Destimated according to the weight of course it can be calculated by formula:
/ T; N0 V+ j7 P4 Z' z- c8 v6 lL=Si=Vi/0.785Ds2
; l& ^- ?( w' ?) w. [; |- H1 Q+ HL:注射行程; Si: 注射行程;
# K: B) a- F8 [; n4 oL: injection stroke Si: injection stroke
& n3 q0 T4 |4 R# J1 BVi:理論注射容積; Ds:螺杆直徑;
9 s3 `0 S! P& Z9 t, m% q2 \# mVi: injection volume of theoretical Ds: diameter of screw
! u& U5 \$ M( n/ v( r0.785:是Ω/4的值.
2 B0 T+ S* g8 Q( D1 M5 l" V0. 785: value of Ω/4.
* J$ d) Z' z5 E7 t# {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.+ P8 k* `* ]- x% Y
But it cost a lot of time to produce one product if every time molding
, D$ g1 H2 d7 c. @) Xparameter is setting by calculation.
' r' A ~$ h+ E1 L v2.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! v) M+ Z6 v0 u6 V, t/ |Step 2 inject 2/3 of product. It can lower 2/3 of product according to # w3 r1 M: P4 v7 |5 }: j
requirement of product. For example to prevent weld line. Molding speed
! W6 T" i5 U( ~: ~5 d6 a6 c6 oand pressure on this step is the maximum of whole molding section. If / D5 R1 b+ x0 x
Mold suit the injection molding machine and mold structure reasonable
6 [* ^# I6 ?3 E. O* p4 Q$ cand eject air well, pressure of this step should lower 80%. Molding speed U* }7 y/ s8 X, h r1 F2 \4 K
setting within 55-80% but it may setting 95% for especial product.
5 H3 y; ^1 H+ g9 Y3.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.( M- p- H+ \$ L2 u. Z, |
Step3 inject remain 1/3 of product. According to product molding speed
6 K* f0 p% h: _' xand pressure lower than that of step2 To prevent flash speed and
1 m0 B. ~; a# T4 ?8 I. O* dpressure should decrease but it can’t shot short.1 g9 i2 g- L% R- u/ l& A2 K
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., E8 P M7 @1 e$ U& x- ?
Step4 section: Some injection machines have step5,step6 which are same
) Y. v; D* ]( A& i. ?5 {as former molding speed and pressure this step should diminish and
9 i) v" \# q( z u! ~inject once more.
1 I E/ G' o- d5.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.
# u3 t1 ~* [3 W+ fHolding pressure step: No matter what product there is a holding ; V6 }' }6 J) L0 l: t) O
pressure step. Any product can’t molding a same thickness. Usually the 9 f' a& `: ?' F1 R' W" G$ ?! P
deeper section may sink mark . To prevent this defect it should set holding
0 Y; r6 ^, {: S- M7 m6 Hpressure, The injection speed of holding pressure step is slow but
7 R- l8 g) X9 L! Yholding pressure setting within 25-80% depending on sink mark3 X# O( s" I( J" B% X
% j2 r) v( C4 i7 d+ w4 ~; P$ G) c
within 40.C-60.C, If oil seal work on condition that high pressure and
4 M6 V# x, ?$ X+ O: t6 R" N& jdamaged It’s work time will be shorter, it can cause molding stable.$ t& C6 l# _9 _, @, e
二.熔膠段工藝
8 O$ G c8 Z3 YPlastic Technique4 _2 Q: l: e- F5 W1 q
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.% Y- T S4 Y0 L3 |# I
Plastic should lower 3 steps, because plastic is a step to add melt " ?" m& d; Q, P6 K" Z
resin material to cyclinder , Higher stick of resin material ,higher screw
4 M! W4 ^: c( c3 Y! i E4 g% vback pressure. Screw speed differs depending on decomposing temperature # ]: ]! E2 H) v2 e+ l, h
of resin material ,Higher screw speed ,Higher trim force of resin,
3 C2 O" X J; Z, u: Z% thigher cyclinder temperature. Some resin material may decomposes so it set : [! c- ^4 b6 t" y0 v1 u
screw speed in mid-speed such as 45-75%, In plastic step setting screw
M% Q& @5 I4 f* [, U! Qback pressure is very important, Higher screw back pressure ,higher
2 N/ g: m8 y r7 pquality of product screw back pressure make resin structure order, Molding
) y9 T @* |# j" |product is beautiful and volume stable. But ,it maybe flow if screw ! m, Q* s3 b w1 Z
back pressure too high . So all factors should be considered when using
8 d2 k4 W( c; `screw back pressure. , c4 r9 v4 _" Y; G% G( `/ S
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.
3 T" _5 ?$ t6 U9 A d9 Q. HIn plastic step sucking back is very important too. Sucking back
3 R" j5 Y5 C+ x* Kinclude front sucking back and back sucking back It setting sucking back to 8 Q# v$ s/ D D7 ^ [ W5 }) @& X
prevent flow and line. It sets sucking back speed and pressure within ! j1 |1 ^! ~- a6 L1 t& T4 N2 }
20-50% and distance within 2-5cm. TOO long distance make cyclinder
6 W- a, Y9 ?3 W8 t7 zreserve air and cause bubble at next molding. |
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