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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5 ^) f+ V m [) ?, G
Heating technique parameter setting
2 _9 f; i0 U3 D( \- t3 \: e1.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) J) |. m3 ]The proper temperature setting differs depending on type of resin 0 n7 S! K# u) {0 r/ B, D
material, but it must be abide by a rule that temperature setting should
* O, E8 i6 x @1 \diminish in step 10.C from nozzle to feeding resin material position.
3 h1 O+ G% b% D% B$ `3 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.
7 `" W, a' u, G: F1 ?! }' s3 ~" b1 d尼龍等.
/ @! y" N Y" \9 q) G+ ]; wNozzle temperature setting should low if product line. If resin 7 q5 G: t5 M* Q# |8 j/ Q
material such as PPS, PA, cool very soon , Nozzle temperature should higher
) e$ ~( d- C0 _ i4 Q) V8 ?more 10.C than the second cylinder temperature.
; h6 J- W% }/ X2 u; q! q& i+ {( Q3.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.
/ Z) x/ u; j) b6 ^Pump turning on temperature is different depending on type of injection
5 ~3 B" P" X4 Y: Gmolding machine. To protect oil seal of machine it set oil temperature
$ h1 J7 |( p @" A! i第三節注射及熔膠(加料)工藝條件設定9 k0 a' S; |& N
Injection and plastic Technique parameter setting
, @# B, ^, z b一.注射
1 B( f6 A8 W! I$ n. jInjection9 O" B1 c1 g4 d# k+ F/ v
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:
. ~: h9 h; |& j5 JInjection is a step which inject melt resin material into mold. It & v: u! e& B2 Z- k
consists of stepl,step2 ,step3,step4 and holding pressure step:
Y& d- \# H- b+ c. W1.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:- C8 M! Y6 E9 J7 N) }- f9 x
Step l injects usually tunnel material, Injection Volume can be 0 i* ]1 O7 w6 V8 _& z" m+ ]
estimated according to the weight of course it can be calculated by formula:* ^" Z9 y3 i8 s- p( j8 Y5 G* B' O
L=Si=Vi/0.785Ds2
% i% U k {, _/ oL:注射行程; Si: 注射行程;0 c* p( h1 x) y7 J7 u+ D s) k
L: injection stroke Si: injection stroke, L; M3 U# z1 W+ `' ?- a* T
Vi:理論注射容積; Ds:螺杆直徑; . m7 O$ ]6 A6 V! z8 x
Vi: injection volume of theoretical Ds: diameter of screw
$ {, R# ?6 Z1 ~( I0.785:是Ω/4的值.5 n! ~4 q) `2 ?( p# A# _& V4 G
0. 785: value of Ω/4., u" x) k- e: N5 a5 @- H
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.
) u2 ]4 b& w; [1 P5 UBut it cost a lot of time to produce one product if every time molding
/ Z; S6 i9 D9 i! V4 X4 y9 X* Pparameter is setting by calculation.
7 |5 Y7 C* u4 Q$ q! D2.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.% {% R; j0 X" _$ Z1 D4 u( C
Step 2 inject 2/3 of product. It can lower 2/3 of product according to : [9 ?/ {( f- n( ^4 i! r
requirement of product. For example to prevent weld line. Molding speed
" Z( J, o) h J6 _5 Y8 y2 ^* sand pressure on this step is the maximum of whole molding section. If
8 P( W1 B6 u4 ~Mold suit the injection molding machine and mold structure reasonable
3 ~3 P) \! ~! t/ R0 `. `$ O/ A3 C' Land eject air well, pressure of this step should lower 80%. Molding speed 0 d! _' p$ L6 {/ B5 u" l
setting within 55-80% but it may setting 95% for especial product.
1 h: V3 V2 |$ D3.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.
2 ^" C( O Z# e) cStep3 inject remain 1/3 of product. According to product molding speed
' L' L4 l3 O) l5 u) k8 _9 Z( sand pressure lower than that of step2 To prevent flash speed and & z3 l2 V; c8 Y; k0 ^
pressure should decrease but it can’t shot short., X8 y2 h: l( D
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.: K. E$ n# b% Y# K) Q$ C: c
Step4 section: Some injection machines have step5,step6 which are same % S1 e. k# E: ?* n9 R
as former molding speed and pressure this step should diminish and
2 f9 X1 P- A5 |$ C$ ^& ?; _inject once more.8 E; t7 ^% j! z! W ^) i
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.
/ U# u6 k& U& c: B' T$ kHolding pressure step: No matter what product there is a holding % q9 e7 f6 {: G
pressure step. Any product can’t molding a same thickness. Usually the
" x" U; q0 t6 J2 v r8 F% ddeeper section may sink mark . To prevent this defect it should set holding 9 x8 b1 f3 | t# P" ~) U
pressure, The injection speed of holding pressure step is slow but
; X2 p* V2 P+ @) l! d+ f, _! {holding pressure setting within 25-80% depending on sink mark
* L; T, H5 O3 K8 _, x
% u/ t/ X; D- ?: y/ }/ R! X6 Mwithin 40.C-60.C, If oil seal work on condition that high pressure and + c- i) O8 x+ t* y5 I* v. G$ B
damaged It’s work time will be shorter, it can cause molding stable.# ^6 i: k5 S2 O$ N5 |! Y+ J; E
二.熔膠段工藝/ @; V4 A2 Q `8 P/ Q) q9 ?0 q
Plastic Technique" c* F( b# ~4 M9 M# 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.
" z/ K: I# ^. x1 u) V) ~5 _Plastic should lower 3 steps, because plastic is a step to add melt 6 [+ Y0 |/ {; ^, s$ |
resin material to cyclinder , Higher stick of resin material ,higher screw
- z, Q& S$ Z+ Q2 x/ c7 F! Y7 r8 U7 Nback pressure. Screw speed differs depending on decomposing temperature
. A% ]" ?" A: h* eof resin material ,Higher screw speed ,Higher trim force of resin,
5 c5 W, Q9 S: q! @0 b$ chigher cyclinder temperature. Some resin material may decomposes so it set
7 t1 Y" ~/ i# p6 z0 R% Cscrew speed in mid-speed such as 45-75%, In plastic step setting screw 3 `% N B, n" D9 o0 w5 y% R
back pressure is very important, Higher screw back pressure ,higher
9 T- d- {- l+ v P8 ?& F- ]quality of product screw back pressure make resin structure order, Molding
! m/ [4 } I U: q% Q# w) B qproduct is beautiful and volume stable. But ,it maybe flow if screw
- c4 [: L# Q( t, Xback pressure too high . So all factors should be considered when using
. O: t- v. V6 Y8 Uscrew back pressure.
# D4 ^( T& j2 z: b3 K& U2.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.
- n) J! v" k m! I5 J# e* NIn plastic step sucking back is very important too. Sucking back
, |, d. p% M2 ^/ s! Kinclude front sucking back and back sucking back It setting sucking back to
# a6 c1 O* B j% y7 O! Y, _& {. Eprevent flow and line. It sets sucking back speed and pressure within 8 Y/ E0 j8 e2 R
20-50% and distance within 2-5cm. TOO long distance make cyclinder ) R8 T4 u8 J7 S
reserve air and cause bubble at next molding. |
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