耳機注塑模具設(shè)計
耳機注塑模具設(shè)計,耳機,注塑,模具設(shè)計
注塑成型工藝流程及條件介紹
成型條件設(shè)定
按成型步驟:可分為開鎖模,加熱,射出,頂出四個過程.
鎖模條件設(shè)定:
1，鎖模一般分: 快速→中速→低壓→高壓
2.，快鎖模一般按模具情況分,如果是平面二板模具,快速鎖模段可用較快速度,甚至于用到特快,當(dāng)用到一般快速時,速度設(shè)到55-75%,完全平面?？稍O(shè)定到 80-90%,如果用到特快就只能設(shè)定在45-55%,壓力則可設(shè)定于50-75%,位置段視產(chǎn)品的深淺(或長短)不同,一般是開模寬度的1/3.
3，中速段,在快速段結(jié)束后即轉(zhuǎn)換成中速,中速的位置一般是到模板(包括三板模,二板模)合在一塊為止,具體長度應(yīng)視模板板間隔,速度一般設(shè)置在30%-50%間,壓力則是20%-45%間.
4，低壓設(shè)定,低速設(shè)定一般是在模板接觸的一瞬間,具體位置就設(shè)在機臺顯示屏顯示的一瞬間的數(shù)字為準(zhǔn),這個數(shù)字一般是以這點為標(biāo)準(zhǔn),,即于此點則起不了高壓,高于此點則大,輕易起高壓.設(shè)定的速度一般是15%-25%,視乎不同機種而定,壓力一般設(shè)定于1-2%,有些機則可設(shè)于5-15%,也是視乎不同機種不同.
5.高壓設(shè)定,按一般機臺而言,高壓位置機臺在出廠時都已作了設(shè)定,相對來講,是不可以隨便更改的,比如震雄機在50P.速度相對低壓略高,大約在30-35%左右,而壓力則視乎模具而定,可在55-85%中取,比如完全平面之新模,模具排氣良好,甚至于設(shè)在55%即可,如果是滑塊較多,原來生產(chǎn)時毛邊也較多,甚至于可設(shè)在90%還略顯不足.
加熱工藝條件設(shè)定
1.加熱段溫度設(shè)定必須按照產(chǎn)品所使用的原料的不同而不同,但卻必須遵循一個這樣的規(guī)則,即由射口筒到進科段溫度是逐步遞減的.且遞減溫度是以10.度為單位.
2特殊情況下.如料頭抽絲,則射口筒溫度應(yīng)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(jié)法蘭溫度高10度.比如PPS. 尼龍等.
3.機臺馬達啟動溫度視乎機臺不同而不同,一般出于對機臺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(wěn)定.
注射是把塑料原料經(jīng)加熱后射進模腔的過程,它一般可分為第一級,第二級,第三級,第四級及保壓幾段:
1 .第一級注射一般是注射料頭段.具注射量一般可根據(jù)料頭的輕重來估計其行程,當(dāng)然也可以依據(jù)公式來計算,如公式
L=Si=Vi/0.785Ds2:
L:注射行程; Si: 注射行程;
Vi:理論注射容積; Ds:螺桿直徑;
0.785:是Ω/4的值.
當(dāng)然,如果我們在成型時每設(shè)定一個參數(shù)都要計算一次,要成型出一個產(chǎn)品就要幾個小時才能完成了.
2. 第二級是注塑產(chǎn)品約2/3的階段,當(dāng)然,根據(jù)產(chǎn)品特殊需要,也允許成型不到2/3階段,比如避免結(jié)合線問題,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,如果排的產(chǎn)品與機臺基本是相吻合的.模具結(jié)構(gòu)合理,排氣良好,這一段的壓力一般也不會超過80%.速度側(cè)視產(chǎn)品需變,可能大到95%也可,自然一般都是在55%-80%間.
3. 第三段是注射余下的1/3段,其速度和壓力根據(jù)產(chǎn)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.主要是為了防止產(chǎn)品毛邊的產(chǎn)生,但同時又必須把產(chǎn)品充填飽滿.
4.第四段:一般有機臺還有第五,第六段,這段的成型速度和壓力相同前,都存在兩段一個遞減過程.其作用都是起到一個再次充滿的作用.
5.保壓段:不論成型什么產(chǎn)品,都存在一個保壓過程.任何產(chǎn)品都不同程度的存在一個厚薄不一的問題,正常情況下,較厚的部分都可能存在一個收縮凹陷的現(xiàn)象,為了解決這種現(xiàn)象,就應(yīng)應(yīng)用到保壓,保壓一般來講都應(yīng)用較慢的射速,而壓力的設(shè)置則應(yīng)看縮水的情況如何,小到25%,大到80%都有可能.
產(chǎn)品經(jīng)冷卻定型后則有一個開模的過程,開模基本上是合模的反過程.開模的未段則有一個慢速設(shè)置,開模完成后,產(chǎn)品必須頂出的過程.
一.頂前:
頂前最好分兩個階級,第一階可分為中壓慢速,即是把產(chǎn)品輕輕頂出一部分,然后是中壓中速頂,中壓中速一般指的是35%-55%,而低速則有可能低到5%,這需視產(chǎn)品不同而言,頂出行程設(shè)定是頂出長度稍比產(chǎn)品垂直深度大1-2cm即可.
二.退針
頂退包括兩個過程與頂落的過程基本一致,頂退的終點應(yīng)預(yù)留1-3cm的空間,以保護頂針油管不被頂壞.
三.頂針
頂針方式還包括一個多次頂,單次頂及頂針停留的選擇,機械手取產(chǎn)品,脫模順利的情況都采取多項,為了頂針油缸 壽命的延長,多次頂就以不超過三次
為宜,頂針停留一般用在頂針帶著產(chǎn)品退回有可能對增品產(chǎn)生損傷的模具,同時為配合機械手使用,有時也需要較短的頂針停留.
Injection molding technical process and condition introduction
Section Molding parameter Setting
Molding steps: mold opening/closing, heating injection and knocking out.
Mold closing parameter setting
1.Mold closing: high-speed →low-speed →low pressure→high pressure
2.In high-speed section, Mold closing speed depends on type of mold. For two –plate mold it can set quick and even especially quick usually, it set speed within 55-75%. For full-plate mold it set speed within80-90% while using especially high speed it set speed within 45-55% and pressure within 50-75% position distance setting differs depending on the volume of product and usually it can be set 1/3 of mold opening position.
3.In mid-speed section: Mold closing speed changes into mid-speed after high-speed section finish. Mid-speed start position is where two plates meet (include three-plate mold and two-plate mold ) Distance of mid-speed is up to distance of two plates plate it speed within 30-50% and pressure 20-45%.
4.Low-pressure section: Mold closing sets low-pressure when plates meeting. This position is set to the data of machine screen on this time. This point is the gage of the data. Data lower the point there is no high-pressure. Data higher the point there is high-pressure easily. It set speed within 15-25% and pressure within 1-2% depending on type within 1-2% depending on type of injection molding machine.
5. High-pressure section: To normal injection molding machine, high-pressure position had been set before they were sent to customer. It can not be modified. For example high-pressure position of CHENHSONG machine is 50P.The speed of high-pressure section is about 30-35% and higher than that of low-pressure. The pressure is up to mold, it can set within 55-85% For full-plate mold, it’s eject air well, it can set pressure 55% .If mold has a lot of slides and flash rate high in production, pressure can set 90%.
Heating technique parameter setting
1.The proper temperature setting differs depending on type of resin material, but it must be abide by a rule that temperature setting should diminish in step 1０.C from nozzle to feeding resin material position.
2 Nozzle temperature setting should low if product line. If resin material such as PPS, PA, cool very soon , Nozzle temperature should higher more 10.C than the second cylinder temperature.
3. Pump turning on temperature is different depending on type of injection molding machine. To protect oil seal of machine it set oil temperature within 40.C-60.C, If oil seal work on condition that high pressure and damaged It’s work time will be shorter, it can cause molding stable.
Injection is a step which inject melt resin material into mold. It consists of stepl,step2 ,step3,step4 and holding pressure step:
1. Step l injects usually tunnel material, Injection Volume can be estimated according to the weight of course it can be calculated by formula:
L=Si=Vi/0.785Ds2
L: injection stroke Si: injection stroke
Vi: injection volume of theoretical Ds: diameter of screw
0. 785: value of Ω/4.
But it cost a lot of time to produce one product if every time molding parameter is setting by calculation.
2. Step 2 inject 2/3 of product. It can lower 2/3 of product according to requirement of product. For example to prevent weld line. Molding speed and pressure on this step is the maximum of whole molding section. If Mold suit the injection molding machine and mold structure reasonable and eject air well, pressure of this step should lower 80%. Molding speed setting within 55-80% but it may setting 95% for especial product.
3. Step3 inject remain 1/3 of product. According to product molding speed and pressure lower than that of step2 To prevent flash speed and pressure should decrease but it can’t shot short.
Step
4 section: Some injection machines have step5,step6 which are same as former molding speed and pressure this step should diminish and inject once more.
5. Holding pressure step: No matter what product there is a holding pressure step. Any product can’t molding a same thickness. Usually the deeper section may sink mark . To prevent this defect it should set holding pressure, The injection speed of holding pressure step is slow but holding pressure setting within 25-80% depending on sink mark.
There is a mold opening step after product cooling taking shape. Mold opening is a reverse step of mold closing. The last step of mold opening speed set slow. Product should be knocked out after mold opened.
one.Knocking out
Knocking out includes two steps, Step1 section setting mid-speed, knocks product out partly step2 section setting mid-pressure and mid-speed . Depending on different product, mid-pressure and mid-speed sets within 35-55% but low-speed can set 5%. Distance of knocking out longer 1-2cm than the vertical thickness of product.
two.Back
The same as knocking out, ejector back includes 2 steps. To protect the ejector oil jar, it should make a 1-3mm distance in the ending point of ejector back.
Three. Thimble
The way of knocking out includes knocking out once, Knocking out repeat and ejector delay. Take product by manipulator or take product easy, it should select knocking out once. To longer the work time of ejector oiljar, times of knocking out lower 3 times. Ejector delay used when product will be damaged if ejector back or suit manipulator.
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