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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" |3 Q D8 p# s2 B* M8 Q
Heating technique parameter setting; J# t# ?1 R* R/ B
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.
' H" r3 k7 |) g* S6 i+ u+ WThe proper temperature setting differs depending on type of resin
, C, h0 `6 C( j' Z8 T+ S, wmaterial, but it must be abide by a rule that temperature setting should 9 `& P, X; {/ d+ C4 h/ m8 p
diminish in step 10.C from nozzle to feeding resin material position. # r6 T% |5 ]& D1 {+ Z
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. $ [* f0 h8 e& I* V( u7 ]4 l+ T+ _
尼龍等.. F: R; D! I; R* k6 V
Nozzle temperature setting should low if product line. If resin ) t6 ]: U6 B; O% @* n( ^1 A! F0 h
material such as PPS, PA, cool very soon , Nozzle temperature should higher
4 a2 Q1 ^5 D. v! mmore 10.C than the second cylinder temperature.4 ?" Y3 w9 r( o4 {/ D _
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* H- d1 x. P: S$ h0 g
Pump turning on temperature is different depending on type of injection 2 q" D+ e, m) {; {: j5 h
molding machine. To protect oil seal of machine it set oil temperature
4 g* m+ Y/ _5 \# z& T- U第三節注射及熔膠(加料)工藝條件設定# x, _8 f) B2 l. L+ |4 L
Injection and plastic Technique parameter setting5 ~+ l: {1 m* q5 a# P) T6 ~
一.注射
9 \; S! L. z2 ]; _+ uInjection5 ?! Z. ~& R, a- a4 F3 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:
; i. }" \, `& B1 c) d! o4 _7 VInjection is a step which inject melt resin material into mold. It ) }4 K J3 }! D: L3 j% G9 N
consists of stepl,step2 ,step3,step4 and holding pressure step:
# w2 o& ?- t1 o6 I1.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:; F4 m! q, y/ X. a1 k% f
Step l injects usually tunnel material, Injection Volume can be
) X# u0 x- `9 F6 M* jestimated according to the weight of course it can be calculated by formula:
# \$ P3 |% V4 y1 N; e s$ R3 EL=Si=Vi/0.785Ds22 x) H4 z% h9 L4 P: \5 `
L:注射行程; Si: 注射行程;
6 \' k1 p, W$ `# J- K: f8 hL: injection stroke Si: injection stroke
: p! g" h0 ]3 F' {Vi:理論注射容積; Ds:螺杆直徑; 6 m. i1 m8 b& J8 A8 z# o7 t
Vi: injection volume of theoretical Ds: diameter of screw
, X$ i8 ]& Z6 c2 }, \* H0.785:是Ω/4的值.8 C: c% w$ A$ C% H
0. 785: value of Ω/4.
) y. A) \: l2 h i2 ?4 f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.+ ]) q, `7 ~! f+ O* M, x, c7 k U& E
But it cost a lot of time to produce one product if every time molding " l* x3 Y& Y! L- E0 U, C
parameter is setting by calculation.! d# @; A7 [+ I7 [
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.( F6 ~3 X4 D, S. d
Step 2 inject 2/3 of product. It can lower 2/3 of product according to 7 `- B, }2 o/ O \
requirement of product. For example to prevent weld line. Molding speed
+ _6 f; T) B4 { f; nand pressure on this step is the maximum of whole molding section. If 2 ?" D7 ]4 b+ d/ Z+ {, b B
Mold suit the injection molding machine and mold structure reasonable % r( ]7 V) @, X0 Z9 G3 ^$ D/ }! l- m
and eject air well, pressure of this step should lower 80%. Molding speed : T4 y! U4 H! L0 J5 G
setting within 55-80% but it may setting 95% for especial product./ M% L2 z, H9 C: O2 y8 X9 q
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.* a4 I2 n" r% |6 Y
Step3 inject remain 1/3 of product. According to product molding speed
. Q- q; A+ v! F8 fand pressure lower than that of step2 To prevent flash speed and
4 a R4 l& l$ ~ K5 Wpressure should decrease but it can’t shot short.
; ~2 @) j2 q! W$ i- L& D: P4.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.& S& w6 D# y: X: z- D
Step4 section: Some injection machines have step5,step6 which are same
3 L1 A8 B" d3 e/ |0 w0 X1 b% nas former molding speed and pressure this step should diminish and
0 t) J3 _" M2 j* J3 x/ m4 m& ~0 Finject once more.$ B; W) y/ F B( }) l" |
5.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.! N5 G6 P( ]# r& i) q5 G) W
Holding pressure step: No matter what product there is a holding 2 I& @- |2 J. W |9 _
pressure step. Any product can’t molding a same thickness. Usually the 3 E- X- q6 m4 V" H. A r
deeper section may sink mark . To prevent this defect it should set holding
( w" J$ ^; t, B% v' A& B- K3 d Opressure, The injection speed of holding pressure step is slow but 6 E7 S7 u8 t6 H1 S
holding pressure setting within 25-80% depending on sink mark
5 b9 c8 l, {+ \' m- @( Y- ]# U) B
/ q' \/ r: n9 m/ Ewithin 40.C-60.C, If oil seal work on condition that high pressure and % v% V0 P! t6 K, G1 H- R1 D
damaged It’s work time will be shorter, it can cause molding stable.
- q% }: y n( S+ _, X( q! O二.熔膠段工藝& W; f: c) F1 I
Plastic Technique$ g# ~& A5 c/ P1 w. ^% X: h
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.
( \) f6 H+ I6 [+ A5 _Plastic should lower 3 steps, because plastic is a step to add melt & v9 N/ ^3 k0 k2 H
resin material to cyclinder , Higher stick of resin material ,higher screw
8 L" \% y8 M* M9 S3 @3 C% Rback pressure. Screw speed differs depending on decomposing temperature 4 g9 `) S4 P6 i, d1 c0 Z2 x
of resin material ,Higher screw speed ,Higher trim force of resin,
- L1 t7 j5 s3 |2 j. H/ c7 Rhigher cyclinder temperature. Some resin material may decomposes so it set
, ]& t) |# H4 {8 C; Lscrew speed in mid-speed such as 45-75%, In plastic step setting screw
8 g2 E$ k" m8 [& _# |back pressure is very important, Higher screw back pressure ,higher & e& K, H V3 V6 `& @" ~- B, p/ K1 q
quality of product screw back pressure make resin structure order, Molding
) Q6 x6 u) \4 }& I' \- K/ s' u6 @product is beautiful and volume stable. But ,it maybe flow if screw
/ _4 X7 u$ F; Zback pressure too high . So all factors should be considered when using
5 j6 D+ L5 _5 }* z/ _& U9 dscrew back pressure. : H5 h5 _" T% B6 e+ Z, o, D" t
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.
7 w# ~: a+ m- _& |2 h9 o& w2 w* L* fIn plastic step sucking back is very important too. Sucking back ) y9 i8 q1 Y) [+ ^1 V
include front sucking back and back sucking back It setting sucking back to , h4 Q5 \! H. \, L8 S
prevent flow and line. It sets sucking back speed and pressure within 4 _1 }3 _0 z7 O( P0 D
20-50% and distance within 2-5cm. TOO long distance make cyclinder
3 A- |" U# X0 R) o2 d$ Ireserve air and cause bubble at next molding. |
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