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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 }+ S7 r) {' K2 P
Heating technique parameter setting
8 F- I& B8 H. q& @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.9 l" G* w7 L& v
The proper temperature setting differs depending on type of resin # t, A% n7 Y6 f1 ` A
material, but it must be abide by a rule that temperature setting should : B% K+ }2 c( z) x: O
diminish in step 10.C from nozzle to feeding resin material position.
" u4 M/ T3 M3 P3 ~8 k2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.
1 J8 y3 r9 l! O7 R尼龍等.8 ?' z1 Y' _+ M, v6 J# o
Nozzle temperature setting should low if product line. If resin
% N/ p$ [* b" [. d) ] C9 m3 pmaterial such as PPS, PA, cool very soon , Nozzle temperature should higher
, U# R e) |: v6 v8 C/ [! u; ~more 10.C than the second cylinder temperature.
4 B2 j# d/ Y5 T2 N% B- k* j# E& N3.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." o* ?2 X6 U a' {/ V p N; a: `
Pump turning on temperature is different depending on type of injection
2 z- L( o" j* ~$ h# fmolding machine. To protect oil seal of machine it set oil temperature
1 Y Y# K- g# i) o/ }$ Y0 A+ p第三節注射及熔膠(加料)工藝條件設定 a6 z+ I# q* N) _% _3 j
Injection and plastic Technique parameter setting
" F# g8 D' F. C# G( r一.注射
- M, p, r ~) y8 _Injection; a1 c6 [$ c9 m; ^% _) ^
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:
3 X5 A h) h5 J+ o+ q! aInjection is a step which inject melt resin material into mold. It
4 m6 i. v: G( u7 C0 g* P; Cconsists of stepl,step2 ,step3,step4 and holding pressure step:6 p' r. w1 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:
& Y* I7 T; Z" ~, X/ qStep l injects usually tunnel material, Injection Volume can be
$ {0 C% i. j6 ~# q/ M0 Festimated according to the weight of course it can be calculated by formula:
7 b; U( M/ A4 CL=Si=Vi/0.785Ds2; I3 K! t8 |' L( a0 Y
L:注射行程; Si: 注射行程;9 V% I A3 o/ z" t# U6 g/ h) E
L: injection stroke Si: injection stroke
9 e1 F2 d' q* YVi:理論注射容積; Ds:螺杆直徑; , s X' `- h, r$ ~
Vi: injection volume of theoretical Ds: diameter of screw
. n( e" F6 @6 L! g+ j" A0.785:是Ω/4的值.
. n `* s% U# T! ^0. 785: value of Ω/4.
5 l$ K4 _4 K* h6 g+ I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.
# g6 G: k. h" X& }* SBut it cost a lot of time to produce one product if every time molding
+ d5 i/ c2 P. q+ {$ ]: fparameter is setting by calculation.7 p3 z$ E; R! U* 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.
" B7 j. B# J. j1 E" f# ?6 ^Step 2 inject 2/3 of product. It can lower 2/3 of product according to
2 B7 F [; ]2 [6 {requirement of product. For example to prevent weld line. Molding speed # h( y+ k4 X$ X, H* N& |5 I
and pressure on this step is the maximum of whole molding section. If
$ e0 @/ l0 p- ~- L4 ], v' N2 I6 YMold suit the injection molding machine and mold structure reasonable
8 o9 M) I3 \6 m; b. H; Q land eject air well, pressure of this step should lower 80%. Molding speed
6 s$ ]7 ~: s! @( A9 v: Y" l2 ssetting within 55-80% but it may setting 95% for especial product.2 l/ M/ S' X# ]/ \' q0 v1 e! x
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.
4 P' B6 q! t( n3 N1 C. T+ w: P! pStep3 inject remain 1/3 of product. According to product molding speed
; J0 N' ~. c% V4 g. r* t oand pressure lower than that of step2 To prevent flash speed and
/ k" Y8 H& A) D0 D* w7 Npressure should decrease but it can’t shot short.- j, J4 o! g0 I% @9 }
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 Q7 T/ `8 J( F& a" `/ \Step4 section: Some injection machines have step5,step6 which are same
. ~% P, H5 a( Tas former molding speed and pressure this step should diminish and 0 C9 ^4 n1 R5 @* R
inject once more.
3 U9 b$ x- B: m1 f4 z% Z/ 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.
2 x) x8 w5 _) l4 R2 fHolding pressure step: No matter what product there is a holding ' x0 J1 |+ u5 c, I
pressure step. Any product can’t molding a same thickness. Usually the & p4 e# q# D2 T" L/ s- c! ?2 G1 [
deeper section may sink mark . To prevent this defect it should set holding - n* |3 l1 @! X5 c
pressure, The injection speed of holding pressure step is slow but ' W' v" N, w; ]' u
holding pressure setting within 25-80% depending on sink mark$ c) }. X Y2 |# K5 z
" C* } A; E0 v; c2 ^within 40.C-60.C, If oil seal work on condition that high pressure and
2 b3 G" j0 x8 _ B2 i" R+ c- Bdamaged It’s work time will be shorter, it can cause molding stable.
; v- w5 @- t4 a( `3 p( W* H二.熔膠段工藝* a. K1 ]$ Q% f
Plastic Technique
9 o) ^# v4 V3 S' ], j: N1.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.- S# B. E: }( X% b; L; O
Plastic should lower 3 steps, because plastic is a step to add melt
5 Z/ ~4 q5 m0 @& G+ n# q7 bresin material to cyclinder , Higher stick of resin material ,higher screw
3 u! z! `2 _. `back pressure. Screw speed differs depending on decomposing temperature
% U7 R) \% L! l! n( R- T Cof resin material ,Higher screw speed ,Higher trim force of resin, , l5 @2 Q* V% \& `
higher cyclinder temperature. Some resin material may decomposes so it set
! A E, `' O5 j! W* F+ V8 [2 A! Yscrew speed in mid-speed such as 45-75%, In plastic step setting screw
" P4 X; m& v( o1 aback pressure is very important, Higher screw back pressure ,higher * o/ }8 y; ]/ T/ d2 y7 X; Q
quality of product screw back pressure make resin structure order, Molding " c9 p! n& t) t7 M- l. U. `1 \
product is beautiful and volume stable. But ,it maybe flow if screw
1 e2 s' G9 l! F- |9 q6 I7 eback pressure too high . So all factors should be considered when using
- M& l; \- \+ u3 I- bscrew back pressure.
2 p- W; O. A4 B, L2.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 @" o: k: p( g! Y7 X/ r
In plastic step sucking back is very important too. Sucking back 6 @$ n3 D4 w: r
include front sucking back and back sucking back It setting sucking back to : m4 I6 e1 a* d/ c3 H6 @9 s# V, l
prevent flow and line. It sets sucking back speed and pressure within
) Y# b, O* f1 W( r0 }% `20-50% and distance within 2-5cm. TOO long distance make cyclinder
4 U- i8 V! b9 K9 _; W; p3 O6 G& rreserve air and cause bubble at next molding. |
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