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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
# Y; M* e1 K& y; A. t* KHeating technique parameter setting
0 b9 A4 i) ^% }. V$ {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.
3 y, x, g& A1 A- N6 mThe proper temperature setting differs depending on type of resin
& s( y9 R6 H" Rmaterial, but it must be abide by a rule that temperature setting should 0 @# L n/ V& M- u3 A: j
diminish in step 10.C from nozzle to feeding resin material position.
- D, C" O! s# X6 B" a$ f2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.
) f4 ]2 Z# {- u6 t6 Z/ ?尼龍等.
k+ h+ c8 ?7 e5 I3 i5 M( UNozzle temperature setting should low if product line. If resin
1 ^/ {8 K$ _7 R. l" a; cmaterial such as PPS, PA, cool very soon , Nozzle temperature should higher 3 Q( [; Z* x+ ^# |3 D8 V9 m& r
more 10.C than the second cylinder temperature.
2 R3 h3 Q' L3 [- ~9 h T7 _& R3.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.
' v! i3 I: i& Z f! l( oPump turning on temperature is different depending on type of injection D7 p) c0 @7 |5 w
molding machine. To protect oil seal of machine it set oil temperature * T% T5 N: ]; b Z; b6 b
第三節注射及熔膠(加料)工藝條件設定
" d0 U5 I, W/ R0 D$ iInjection and plastic Technique parameter setting
2 W$ `0 i$ R1 l A- N8 F2 F一.注射7 x4 t2 H4 {; C
Injection# K$ |2 h. r$ w7 K7 {( 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:
6 D) r- s; U g# I. ^- b* GInjection is a step which inject melt resin material into mold. It
- @: A3 r5 y- n* M) [7 Fconsists of stepl,step2 ,step3,step4 and holding pressure step:4 Q2 d, X& V; V9 J, U
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:2 s% c1 f- L5 @1 A# l) m
Step l injects usually tunnel material, Injection Volume can be ! G$ ^4 [. W% E2 K2 ^
estimated according to the weight of course it can be calculated by formula:, G$ \/ N u& s/ a
L=Si=Vi/0.785Ds2+ F/ E+ E. G- S* [ Y% H# t* N8 V
L:注射行程; Si: 注射行程;/ V: T& `. m& }( Z' d
L: injection stroke Si: injection stroke) Q. m" P0 ^7 h3 ^% X1 }, Q8 T
Vi:理論注射容積; Ds:螺杆直徑; " x& M+ }* H6 e1 S. S
Vi: injection volume of theoretical Ds: diameter of screw
$ R* [& ?7 U3 y. t+ `( I2 e: f0.785:是Ω/4的值.
3 D {+ t: _( c0. 785: value of Ω/4.- s1 m) x$ K+ c$ R- U7 \
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.7 C6 Z: } J6 B+ e6 O( s4 Z
But it cost a lot of time to produce one product if every time molding
6 p3 A8 q* @7 J; J% m- y# L1 Mparameter is setting by calculation.6 F( @1 l& ^4 O( A# `" X. Q
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.
; c7 \, n$ l/ w/ [% }9 ?* E0 }. ^Step 2 inject 2/3 of product. It can lower 2/3 of product according to
* }: S5 P5 i8 W$ G4 L+ mrequirement of product. For example to prevent weld line. Molding speed
`# ]! @" c6 G& `) `$ wand pressure on this step is the maximum of whole molding section. If 8 k7 n5 o* U; T: Z
Mold suit the injection molding machine and mold structure reasonable , _% n% N# F$ B& C9 t4 h, k
and eject air well, pressure of this step should lower 80%. Molding speed $ b: G8 z" J! u% l6 O3 b
setting within 55-80% but it may setting 95% for especial product.
- _9 D; a3 n( m! y, H8 F }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.
1 O4 z1 _# t$ ~: V4 pStep3 inject remain 1/3 of product. According to product molding speed " w* \, l/ w" W J# v, ^& | O
and pressure lower than that of step2 To prevent flash speed and
" s7 x( I; q* ]5 g; f3 E. B4 Xpressure should decrease but it can’t shot short.- G. q# N$ k% q, u
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.! b6 X: f) l0 I6 I" G
Step4 section: Some injection machines have step5,step6 which are same
, n0 t! k2 j6 u& [0 q1 R3 }, r: gas former molding speed and pressure this step should diminish and $ F& H2 L- c' }2 L5 u
inject once more.
% j9 z/ ]4 `4 U; `7 o" G5.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.) @( A7 b. J& k. n
Holding pressure step: No matter what product there is a holding 0 G4 M8 h* Q T# p/ l
pressure step. Any product can’t molding a same thickness. Usually the 1 r) ]6 T* q9 _
deeper section may sink mark . To prevent this defect it should set holding 1 Z& o. d9 N* l# z; k B N
pressure, The injection speed of holding pressure step is slow but 2 h+ V# ?% `, d; B" T; {, {) G
holding pressure setting within 25-80% depending on sink mark
0 k/ ~2 x3 {% X- i4 k, @3 g' r3 o7 r" T# b3 q) c( M) U
within 40.C-60.C, If oil seal work on condition that high pressure and
1 {* P# v7 }. \+ N: M7 S/ H/ {4 A& idamaged It’s work time will be shorter, it can cause molding stable.: y& j6 ~4 Z) A/ X
二.熔膠段工藝
$ j8 T0 E! v1 X n" I& bPlastic Technique( y6 B1 b, l% v* M* V
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.: @! N% @8 e ]2 u1 C. u7 D
Plastic should lower 3 steps, because plastic is a step to add melt
$ m# I7 l0 @9 vresin material to cyclinder , Higher stick of resin material ,higher screw ; C% {" I/ r1 F2 B' ]
back pressure. Screw speed differs depending on decomposing temperature 1 u4 [3 \3 E: }
of resin material ,Higher screw speed ,Higher trim force of resin, F1 R8 L$ f# s
higher cyclinder temperature. Some resin material may decomposes so it set
* q0 a% g$ b- Z Ascrew speed in mid-speed such as 45-75%, In plastic step setting screw
* K2 o L2 c2 ~6 H) N5 m- N0 O0 dback pressure is very important, Higher screw back pressure ,higher - X: ?: Z& ?# P# U {, ]
quality of product screw back pressure make resin structure order, Molding , Y2 W; }( Q6 j/ W7 N1 o
product is beautiful and volume stable. But ,it maybe flow if screw
# j/ B( C' [% f$ ~2 {* Q2 d* E8 |7 `back pressure too high . So all factors should be considered when using
- O5 G8 _, u \8 f. \2 qscrew back pressure.
: Y' R: H8 W% J0 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.
% z% s' R' w/ A; I$ OIn plastic step sucking back is very important too. Sucking back 3 |/ ~! n- \+ A$ q
include front sucking back and back sucking back It setting sucking back to , g @* L; `; X
prevent flow and line. It sets sucking back speed and pressure within
0 {1 G1 Z% U2 D5 i4 t' r6 L20-50% and distance within 2-5cm. TOO long distance make cyclinder
8 o5 S- a3 B3 S- I* E+ Greserve air and cause bubble at next molding. |
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