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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
( m4 t0 q) v# ?Heating technique parameter setting
* l7 k5 T$ D( f A1.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./ J, h9 I3 W- W- O+ S+ |
The proper temperature setting differs depending on type of resin
" p: K) E2 A: y: U7 Dmaterial, but it must be abide by a rule that temperature setting should
2 }3 F. P6 _& e7 M9 B, Gdiminish in step 10.C from nozzle to feeding resin material position.
" U3 l# v' n! b# e% u: ?# \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. ) @# b D8 g1 i6 T, O
尼龍等.
8 P; B; N! v; @$ }; |+ O& `' NNozzle temperature setting should low if product line. If resin
5 G$ x: s+ |2 b B2 amaterial such as PPS, PA, cool very soon , Nozzle temperature should higher
( g2 W% q! M2 q! t1 |/ n: v3 imore 10.C than the second cylinder temperature.
5 V) ^( ^ m, ?6 u3 N" s$ L7 c# b7 z3.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.' i6 `* K% R, `
Pump turning on temperature is different depending on type of injection 8 ?9 Y# a; [! z0 U
molding machine. To protect oil seal of machine it set oil temperature 2 F# D% O# z: ~3 X% y
第三節注射及熔膠(加料)工藝條件設定- z1 O2 Z$ K, g, j6 h# g0 N9 c$ T; ]
Injection and plastic Technique parameter setting
. E$ {$ i# N0 i4 ?6 o% C一.注射8 p1 o! I! r" O7 s) }
Injection
7 m) [4 d3 ^6 @6 ~8 f1 ?" o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:7 H) I# _' ^4 E7 f; Y5 s
Injection is a step which inject melt resin material into mold. It + X% A( b4 A. b: o* { L
consists of stepl,step2 ,step3,step4 and holding pressure step:
- d* Y0 c' D% j$ D0 M7 J) f. o1.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:
: Y+ Y5 @3 B1 BStep l injects usually tunnel material, Injection Volume can be % m1 }4 h1 W. F. `
estimated according to the weight of course it can be calculated by formula:
2 N4 L$ ]1 _5 h/ g$ gL=Si=Vi/0.785Ds2
, b L4 }# q: t4 e2 ]- p2 \# SL:注射行程; Si: 注射行程;
3 M. O5 F0 I7 |% z- iL: injection stroke Si: injection stroke
* q7 u( D8 u9 v, bVi:理論注射容積; Ds:螺杆直徑;
, c4 o& m1 ?" E" C" MVi: injection volume of theoretical Ds: diameter of screw3 C: N8 T* Q, t m7 F0 p
0.785:是Ω/4的值.* z% N2 I1 h9 {5 V& |! j
0. 785: value of Ω/4.3 z+ K& D% l) 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.5 I% T& B) m N: O
But it cost a lot of time to produce one product if every time molding # b0 s& ]' o# U. u; L
parameter is setting by calculation.
6 y8 T- K0 ^& x* W% z+ h, E2.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.1 G; u2 u( x: ?6 j
Step 2 inject 2/3 of product. It can lower 2/3 of product according to
) ~; C; e- q. R" Q1 W- Zrequirement of product. For example to prevent weld line. Molding speed % s, Y, D( i- n; Y6 P
and pressure on this step is the maximum of whole molding section. If 1 \/ V+ S8 b \5 |/ O
Mold suit the injection molding machine and mold structure reasonable
; u/ Z# W. x- }/ c. R6 pand eject air well, pressure of this step should lower 80%. Molding speed
1 V5 o; ` f) f! C0 Osetting within 55-80% but it may setting 95% for especial product.3 }7 _3 H- B% U+ ~- m$ c" k
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.! h X( l" S ?5 ^
Step3 inject remain 1/3 of product. According to product molding speed - G9 s6 o# J9 N
and pressure lower than that of step2 To prevent flash speed and
8 h! K H4 Q+ f( j+ _pressure should decrease but it can’t shot short.% g3 d( C" e( i- d2 b0 N; Y
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.+ f5 D7 i" b1 |8 q- H* o
Step4 section: Some injection machines have step5,step6 which are same ) H) `! z+ J5 q" k0 D
as former molding speed and pressure this step should diminish and
. T) O9 U1 `9 Finject once more.
( o, ]0 c s) W9 L, p! C/ Y5.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.
% M, y- a* G" W6 HHolding pressure step: No matter what product there is a holding
' j6 j7 m& `8 z* ^4 N6 f. ~9 [% Ipressure step. Any product can’t molding a same thickness. Usually the
1 N1 \0 h6 T5 xdeeper section may sink mark . To prevent this defect it should set holding
9 R, V7 Q7 p" L! f7 M) C- u o" {! T8 ]pressure, The injection speed of holding pressure step is slow but
2 o' G4 W5 J% r4 c( O$ F) ^holding pressure setting within 25-80% depending on sink mark, U2 r8 @( R' L5 _# u$ o
6 ]& r2 Y0 u, z- m4 x, s7 g. s* Lwithin 40.C-60.C, If oil seal work on condition that high pressure and
, d( B% ]' g* }5 n! K- s! @5 vdamaged It’s work time will be shorter, it can cause molding stable.$ B5 H# V, x$ D( F0 @
二.熔膠段工藝
0 [. _' q2 A; `+ SPlastic Technique
$ y& T" g, u: Z1 v# V3 q; S1.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.
5 G& R8 ?( i# g) \) v& ?$ z: VPlastic should lower 3 steps, because plastic is a step to add melt
. b, f2 h- F7 n$ @/ t7 y+ Tresin material to cyclinder , Higher stick of resin material ,higher screw
: i8 ^# T% ~+ q" Eback pressure. Screw speed differs depending on decomposing temperature # Y- Z! k; f! c" t( d+ x
of resin material ,Higher screw speed ,Higher trim force of resin, ]5 r3 w" x$ }. K3 V5 n& q# R2 r& `
higher cyclinder temperature. Some resin material may decomposes so it set 1 R, Y8 f4 l+ {( S* g& j: ?( l
screw speed in mid-speed such as 45-75%, In plastic step setting screw ( L) \8 _* n& w6 i% ~
back pressure is very important, Higher screw back pressure ,higher / ]% M- o3 o1 _- ^( Q: x; V8 s/ n8 j
quality of product screw back pressure make resin structure order, Molding
# ?5 G& D. ~, T* C! yproduct is beautiful and volume stable. But ,it maybe flow if screw
2 I @3 j3 a3 _% E, l1 u% nback pressure too high . So all factors should be considered when using ! G# J* a: j/ g; Z5 e
screw back pressure.
* s5 x6 ~( x2 |0 m3 _8 ^# k2.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.) B9 [, ^: ?' {6 l* v
In plastic step sucking back is very important too. Sucking back 7 \# N5 G& y5 z2 p
include front sucking back and back sucking back It setting sucking back to
- H# p. \8 \7 k4 j* I7 Gprevent flow and line. It sets sucking back speed and pressure within # l1 \0 _- K! R# h) b
20-50% and distance within 2-5cm. TOO long distance make cyclinder . B$ k3 F; P/ a& l* M
reserve air and cause bubble at next molding. |
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