電機(jī)端蓋壓鑄模具設(shè)計(jì)【說(shuō)明書+CAD+PROE】
電機(jī)端蓋壓鑄模具設(shè)計(jì)【說(shuō)明書+CAD+PROE】,說(shuō)明書+CAD+PROE,電機(jī)端蓋壓鑄模具設(shè)計(jì)【說(shuō)明書+CAD+PROE】,電機(jī),機(jī)電,壓鑄,模具設(shè)計(jì),說(shuō)明書,仿單,cad,proe
桂林航天工業(yè)高等?？茖W(xué)校
壓鑄模設(shè)計(jì)說(shuō)明書
系 別：機(jī)械工程系
專 業(yè)：模具設(shè)計(jì)與制造
班 級(jí)：2005032101
姓 名：羅 惠 鎮(zhèn)
學(xué) 號(hào)：200503210135
指導(dǎo)老師：葉東老師
2008年01月02日
一、零件圖
如圖1-1所示制件為電機(jī)端蓋,材料為鋅合金,屬大批量生產(chǎn)。
圖1-1
一、該壓鑄件的材料分析和工藝性分析
1. 材料分析
該產(chǎn)品的成型材料是鋅合金，該材料密度大，鑄造性能好，可壓鑄復(fù)雜的零件，壓鑄時(shí)不粘模，壓鑄件表面易鍍Cr、Ni等金屬，機(jī)械切削性能好，但易老化，抗腐蝕性能不高。
2. 工藝性分析
1）鋅合金壓鑄，其鋅不容易就粘在模具表面上。
2）該壓鑄件壁厚比較均勻，各個(gè)孔小且淺，工藝性好。
3）為了方便加工與成型及脫模，型腔、型芯均采用組合式結(jié)構(gòu)。
4）該壓鑄件是一般精度等級(jí)。為降低設(shè)計(jì)難度和設(shè)計(jì)周期，應(yīng)采一模一腔，且需要對(duì)壓鑄件去除澆口廢料。
二、擬定的成型工藝
1.成型方法
該壓鑄件采用沖頭下壓式全立式壓鑄機(jī)壓鑄。
2.各工藝參數(shù)
1）經(jīng)查教材（壓鑄成型工藝與模具設(shè)計(jì)）第32頁(yè)表3.2可知壓射比壓為30Mpa
2）經(jīng)查教材第33頁(yè)表3.4可知壓射沖頭空行程壓射速度為0.3～0.5m/s
3）經(jīng)查教材第34頁(yè)表3.5可知充填速度為15 m/s
4）經(jīng)查教材第36頁(yè)表3.7可知持壓時(shí)間3～4s
5）經(jīng)查教材第36頁(yè)表3.8可知留模時(shí)間推薦值為7～12s
6）經(jīng)查教材第37頁(yè)表3.9可知澆注溫度為410～540
7）經(jīng)查教材第38頁(yè)表3.10可知模具預(yù)熱溫度130～180和工作溫度180～200
3. 確定型腔數(shù)目
1)為降低設(shè)計(jì)難度和設(shè)計(jì)周期，應(yīng)采單型腔，且需要對(duì)壓鑄件去除澆口廢料。
2）計(jì)算壓鑄的體積和重量
通過(guò)三維制圖PRO/E軟件測(cè)量得:
單件壓鑄件投影面積 S=14257㎜2；體積V=153645㎜3
查有關(guān)資料可知Al的密度為6.8g/cm3 則壓鑄件重量m=1044.8g
三、初選壓鑄機(jī)
1.壓鑄機(jī)的鎖模力
模具型腔脹型力中心與壓鑄機(jī)壓力中心重合時(shí)壓鑄機(jī)鎖模力
式中 —壓鑄機(jī)鎖模力，N；
—作用于模具型腔且垂直與分型面方向的脹型力，N；
—作用于滑快楔緊塊面上的法向壓力，N；
K—安全系數(shù)（一般取K=1～1.3）
型腔脹型力
=P（）
式中 P—最終的壓射比壓，Pa；
—鑄件在分型面上的投影面積，㎡；
—澆注系統(tǒng)在分型面上的投影面積與壓鑄件投影面積不重疊部分，㎡；
—溢流槽在分型面上的投影面積，㎡；
壓鑄機(jī)所容許的壓射比壓
式中 —壓鑄機(jī)所容許的壓射比壓，Pa；
F—壓射力，N；
D—壓室直徑，m。
=9500N÷（0.785×）35MPa
= 35MPa×18256㎜263MPa
=1.15×(63 MPa +0)=72.5 MPa
2.選壓鑄機(jī)
根據(jù)以上計(jì)算結(jié)果,經(jīng)查教材第65頁(yè)表4.1可選用熱壓室壓鑄機(jī)型號(hào)為
SHD—75相關(guān)技術(shù)參數(shù)如下表所示：
型號(hào)
規(guī)格
SHD—400
型號(hào)
規(guī)格
SHD—75
鎖模力/KN
400
液壓頂出器頂出力/KN
25
拉桿之間的內(nèi)尺寸（水平×垂直）/㎜
335×285
最大金屬澆注量/Kg
0.75，0.9（Zn）
拉桿直徑/㎜
55
一次空循環(huán)時(shí)間/S
2.5
移動(dòng)模板行程/㎜
195
管路工作壓力MPa
10
壓鑄模厚度/㎜
130～340
坩有效容量/Kg
70
壓射位置/㎜
0～50
噴嘴加熱功率/KW
4
壓射力/KN
42
外型尺寸（長(zhǎng)㎜×寬㎜×高㎜）
3200X1300X1700
四、澆注系統(tǒng)和排溢系統(tǒng)的設(shè)計(jì)
1.澆注系統(tǒng)設(shè)計(jì)
1）確定澆口形式及位置。為了提高成型效率，設(shè)計(jì)與制造簡(jiǎn)單，采用應(yīng)用最為普遍的側(cè)澆口。它開設(shè)在壓鑄件最大輪廓處。
2）澆口直徑可以根據(jù)經(jīng)驗(yàn)公式計(jì)算
式中 —澆口橫截面積，㎡；
m—壓鑄件及溢流槽內(nèi)金屬的總質(zhì)量，㎏；
—液態(tài)金屬密度，㎏/；
—額定充填速度，常取15m/s；
—額定充填時(shí)間，常取0.06s；
分別代表各種修正系數(shù)；
=18
3）直澆道設(shè)計(jì)
分流錐的圓角半徑通常取4～5㎜，直澆道錐通常取～，分流錐通常取～。
2. 排溢系統(tǒng)的設(shè)計(jì)
1）溢流槽設(shè)計(jì)
溢流槽應(yīng)開設(shè)在金屬最先沖擊的部位，排除金屬液流前頭的氣體和冷污金屬液，穩(wěn)定流動(dòng)狀態(tài)，減少渦流；溢流槽應(yīng)開設(shè)在兩股金屬液流會(huì)合的地方，清除集中于
該處的氣體、冷污金屬液和涂料殘?jiān)?。如圖所示
2）排氣槽設(shè)計(jì)
對(duì)于小型模具，可利用分型面間隙排氣，但分型面須位于容體流動(dòng)末端。由于本制品尺寸不大，
利用分型面和推桿的配合間隙排氣即可。
五、壓鑄模零部件設(shè)計(jì)
1.分型面的選擇
該塑件的結(jié)構(gòu)如圖1—1所示，根據(jù)其特點(diǎn)和表面質(zhì)量
要求，應(yīng)采用曲面分型面。分型面設(shè)在零件大端面下一面。
2.成型零部件的結(jié)構(gòu)設(shè)計(jì)
為了方便加工與成型及脫模，型腔、型芯均采用組合式結(jié)構(gòu)
3.成型零部件工作尺寸計(jì)算
1）型腔的徑向和深度尺寸
式中 —模具型腔的徑向尺寸；
—壓鑄件外部形狀的徑向尺寸；
—模具型腔的深度尺寸；
—壓鑄件外部形狀的高度尺寸；
k—壓鑄件平均收縮率；
—壓鑄件尺寸偏差；
—模具的制造偏差。
2）型芯的徑向尺寸和高度尺寸
式中 —模具型芯的徑向尺寸
—壓鑄件內(nèi)部形狀的徑向尺寸
—模具型芯的高度尺寸
—壓鑄件內(nèi)部形狀的深度尺寸
3）中心距尺寸
式中 —模具上型腔或型芯的中心距尺寸；
—壓鑄件凸臺(tái)或凹槽的中心距尺寸
各工作部位尺寸計(jì)算結(jié)果見零件圖紙
通常，制品中1mm和小于1mm并帶有大于0.05mm公差的部位以及2mm和小于2mm并帶有大于0.1mm公差的部位不需要進(jìn)行收縮率計(jì)算。
4.結(jié)構(gòu)零部件的設(shè)計(jì)
1）動(dòng)、定模板一般受拉伸、彎曲、壓縮三種變形力，變形后會(huì)影響型腔的尺寸精度。因此，在考慮各板的尺寸時(shí)，應(yīng)考慮模具結(jié)構(gòu)與壓鑄工藝。
動(dòng)、定模板邊框厚度經(jīng)查教材第121頁(yè)的經(jīng)驗(yàn)數(shù)據(jù)推薦值表6.4
2）合模導(dǎo)向機(jī)構(gòu)設(shè)計(jì)
1.為了使導(dǎo)柱能順利地進(jìn)入導(dǎo)套，導(dǎo)柱端部應(yīng)做成錐形或半球形，導(dǎo)套的前端也應(yīng)倒角。
2.導(dǎo)柱設(shè)在動(dòng)模一側(cè)可以保護(hù)型芯不受損傷，而設(shè)在定模一側(cè)則便于順利脫模取出塑件，因此可根據(jù)需要而決定裝配方式。
3.一般導(dǎo)柱滑動(dòng)部分的配合形式按H8/f8，導(dǎo)柱和導(dǎo)套固定部分配合按H7/k6，導(dǎo)套外徑的配合按H7/k6。
4.除了動(dòng)模、定模之間設(shè)導(dǎo)柱、導(dǎo)套外，一般還在動(dòng)模座板與推板之間設(shè)置導(dǎo)柱和導(dǎo)套，以保證推出機(jī)構(gòu)的正常運(yùn)動(dòng)。
5.導(dǎo)柱的直徑應(yīng)根據(jù)模具大小而定，可參考標(biāo)準(zhǔn)模架數(shù)據(jù)選取。
一次分型導(dǎo)向機(jī)構(gòu)設(shè)計(jì)：導(dǎo)柱固定在固定模板上，與固定模板為H7/m6的過(guò)渡配合。導(dǎo)柱直徑參考標(biāo)準(zhǔn)，取D=12mm，導(dǎo)柱頭部做成半圓形。導(dǎo)柱長(zhǎng)度與主流導(dǎo)長(zhǎng)度點(diǎn)澆口長(zhǎng)度以及塑件長(zhǎng)度等有關(guān)。
Lg= L型芯固板+20=36+20=56mm
六、推出機(jī)構(gòu)設(shè)計(jì)
1.脫模力的確定
脫模力的估算:
式中 —壓鑄件脫模所需的脫模力，N；
P—擠壓力，鋁合金一般?。?0～12）×
A—壓鑄件的包緊型芯的側(cè)面積，㎡；
K—安全系數(shù)，一般取1.2左右
=1.2×（11×）×1200
2. 脫模機(jī)構(gòu)設(shè)計(jì)
壓鑄成型每一循環(huán)中，壓鑄必須準(zhǔn)確無(wú)誤的從模具的凹模中或型芯上脫出，完成模具脫模。脫模機(jī)構(gòu)設(shè)計(jì)應(yīng)遵循下述原則：
1） 壓鑄件滯留于動(dòng)模邊，以便借助于開模力驅(qū)動(dòng)脫模裝置，完成脫模動(dòng)作，致使模具結(jié)構(gòu)簡(jiǎn)單。
2） 推桿設(shè)置不能影響模具的強(qiáng)度。防止壓鑄件結(jié)構(gòu)變形或損壞，正確分析壓鑄件對(duì)模腔的粘附力的大小及所部位，有針對(duì)性的選擇合適的脫模裝置，使推出重心與脫模阻力中心相重合。
3） 推桿應(yīng)設(shè)置在壓鑄件受包緊力最大的地方。由于壓鑄件收縮時(shí)包緊型芯，因此推出力作用點(diǎn)應(yīng)盡量靠近型芯，同時(shí)推出力應(yīng)施于壓鑄件剛性和強(qiáng)度最大部位，作用面積也盡可能大一些，以防壓鑄件變形或損壞。
4） 推桿應(yīng)與型芯的表面齊平。力求良好的塑件外觀，在選擇頂相互位置時(shí)，應(yīng)盡量設(shè)在塑件內(nèi)部或?qū)λ芗绊懖淮蟮牟课弧Ｔ诓捎猛茥U脫模時(shí)，尤其要注意這個(gè)問(wèn)題。
5） 結(jié)構(gòu)合理可靠，脫模結(jié)構(gòu)應(yīng)工作可靠，運(yùn)動(dòng)靈活，制造方便，更換容易，且有足夠的強(qiáng)度和剛度。
根據(jù)制件的形狀，本模具可用設(shè)計(jì)為推桿推出
3. 推桿直徑和數(shù)量的確定
式中 A—推桿工作截面積，；
—壓鑄件推出時(shí)總的壓力，N；
N—推桿數(shù)量；
[]—壓鑄件的許可壓力，MPa。鋅合金一般取50 Mpa
設(shè)計(jì)4根推桿，則推桿工作截面積A=78.5 ，可計(jì)算出推桿直徑為㎜。
4. 復(fù)位桿長(zhǎng)度尺寸：
L4=L頂桿固定板+L支撐板+L型芯板+40
=20+25+30+40=115mm
復(fù)位桿徑向尺寸參考標(biāo)準(zhǔn)見尺寸，取d=10mm
八、壓鑄模的冷卻設(shè)計(jì)
由于壓鑄件平均厚度為4㎜，壓鑄件尺寸不大，確定水孔直徑為8㎜。
由于冷卻水道的位置、結(jié)構(gòu)形式、孔徑、表面狀態(tài)、水的流速、模具材料等很多因素都會(huì)影響模具的熱量向冷卻水的傳遞，精確計(jì)算比較困難。實(shí)際生產(chǎn)中，通常都是根據(jù)模具的結(jié)構(gòu)確定冷卻水路，通過(guò)調(diào)節(jié)水溫、水速來(lái)滿足要求。
九、參考文獻(xiàn)
1. 史鐵梁.模具設(shè)計(jì)指導(dǎo).第1版.北京：機(jī)械工業(yè)出版社，2003
2. 屈華昌.壓鑄成型工藝與模具設(shè)計(jì).第1版.北京:高等教育出版社,2001
3. 王樹勛.注塑模具設(shè)計(jì)與制造實(shí)用技術(shù). 第1版.廣州:華南理工大學(xué)出版社,1996
4. 唐海翔.UGNX2注塑模具設(shè)計(jì)培訓(xùn)教程. 第1版.北京:清華大學(xué)出版社,2005
5. 閻啞林.塑料模具圖冊(cè). 第1版.北京.高等教育出版社:2001
壓塑和壓鑄工藝
近年，壓塑工藝應(yīng)用于熱固性摻混料，如脲醛塑料、酚醛樹脂、環(huán)氧樹脂、蜜胺樹脂和橡膠中。盡管有一些材料可注射成型，但采用壓塑工藝仍非常普遍。壓鑄用材料較壓塑用材料要求可塑性更軟。許多熱固性材料具有高抗沖級(jí)（1.0ft一lb）和良好缺口沖擊強(qiáng)度的保持性，只有在極限壓力下才會(huì)流動(dòng)。
壓塑
熱固性材料的壓塑成型的明顯優(yōu)點(diǎn)是系統(tǒng)簡(jiǎn)單。將材料置入一加熱型腔，保壓至所要求團(tuán)化時(shí)間。因工藝過(guò)程簡(jiǎn)單，費(fèi)用少。添加劑和增強(qiáng)劑無(wú)規(guī)則，并能得到較好強(qiáng)度。由于無(wú)澆口和流道，不浪費(fèi)材料，模具幾乎也不用維修。零件的統(tǒng)一性好，無(wú)鑄口和流痕，減少了修飾成本。根據(jù)制品結(jié)構(gòu)和所用的塑料應(yīng)用特點(diǎn)，可采用全壓式模具、半壓式模具和閉模（可參見有關(guān)壓塑模具方面的文章）。
設(shè)備：簡(jiǎn)單也是壓塑設(shè)備的主要特點(diǎn)。兩半壓板結(jié)合在一起，加溫，加壓，將材料制成預(yù)定形狀。多數(shù)壓塑過(guò)程采用液壓操作；也有采用氣動(dòng)操作的。上下兩壓板在壓力之下在4個(gè)角柱上上下移動(dòng)。根據(jù)壓塑設(shè)備的大小，壓力一般為20—1000噸。壓板的大小一般為8英寸2到5英尺2.
在加料和固化以后的脫模方面存在不同自動(dòng)化程度，常用最現(xiàn)代的液壓機(jī)進(jìn)行。以前的簡(jiǎn)單系統(tǒng)有溫度控制、壓力控制、停壓控制和時(shí)間控制?，F(xiàn)代設(shè)備采用更高級(jí)的微處理機(jī)控制。對(duì)于較薄的制品，在板中可用加熱筒或帶式加熱器。對(duì)較深的制件，需要用筒形電加熱器、蒸汽加熱或熱油系統(tǒng)加熱。有數(shù)種用于壓塑中的加熱體系：用蒸汽加熱模溫均勻，但加熱溫度限在350°F以下；套筒加熱或其它加熱（加熱盤管、加熱帶等）比較干凈，易于保養(yǎng)，用得比較普及；熱油加熱，由于加熱介質(zhì)循環(huán)穩(wěn)定，所以加熱均勻?，F(xiàn)在又有許多新加熱方法，熱水加熱，類似于熱油加熱，加熱介質(zhì)一水一氣體燃燒連續(xù)循環(huán)，可提供更高的壓塑溫度。
增強(qiáng)改性高分子材料工業(yè)發(fā)展迅速，要求壓塑工業(yè)有新改進(jìn)。模塑增強(qiáng)塑料用兩個(gè)模具：陽(yáng)模（模塞）和陰模（模腔）。當(dāng)模具充滿增強(qiáng)材料時(shí)，對(duì)模的兩半熱模具閉合，然后加熱、加壓固化得到產(chǎn)品。相配合的模具復(fù)雜性變化很大，可用鋁、塑料或鋼制做。
輕質(zhì)材料制做起來(lái)比較便宜，一般用于短期生產(chǎn)如“冷模塑”。冷模塑用室溫固化樹脂，但仍使用模具和壓塑液壓機(jī)。長(zhǎng)期生產(chǎn)用硬化鋼模具比較合算，對(duì)截坯口可提供較好的剪切性能和優(yōu)良的光潔度。這些壓塑鋼模采用機(jī)械上適配的截坯口，通常面對(duì)合模區(qū)。用這種對(duì)模的金屬模具，其制品表面均勻，光潔度好。閉模工藝用于壓塑成型、壓鑄成型、注射成型及一些可沖壓的增強(qiáng)復(fù)合材料。
一些熱塑材塑料可壓塑模塑，但一般還是用預(yù)摻混的熱固性樹脂如BMC（預(yù)制整體模塑料）、SMC（片料成型模塑料）、TMC（厚模塑料）、氈片成型等。
氈片成型有時(shí)叫濕成型復(fù)合材料，在液壓機(jī)的作用下將增強(qiáng)材料和樹脂結(jié)合在一起。經(jīng)常在模中放置氈片，將樹脂傾倒在加強(qiáng)材料上。在加壓過(guò)程中樹脂充滿模腔時(shí)加強(qiáng)材料固定不動(dòng)。
若制件有嚴(yán)重的異形或斜度，有必要進(jìn)行預(yù)成型。多數(shù)氈片和預(yù)成型制州在投影面積上需要加150—200磅／英寸2的模壓力。
預(yù)摻混料，如SMC，預(yù)浸樹脂，填料、催化劑和增強(qiáng)料切割成一定大小隊(duì)片狀，再加入熱的模具中（一般300—400°F），在1000～2000磅／英寸2壓力下模塑。
用于SMC的較新的壓塑設(shè)備的總循環(huán)周期可少于一分鐘（從頭到尾）。已經(jīng)發(fā)展了用特殊的液壓裝置推回壓塑機(jī)中料筒，自動(dòng)控制壓板的水平度。
增強(qiáng)塑料，如SMC，用金屬對(duì)模壓塑光潔度好，這對(duì)制件的表面很重要。在加工時(shí)有時(shí)出現(xiàn)纖維狀的收縮。
用內(nèi)模涂層的方法可改進(jìn)表面光潔度。BMC的壓塑過(guò)程是最老的預(yù)摻混后的模塑過(guò)程之一。
填料（木屑、礦物料、纖維素等）的摻混混合是在葉片形的混合器中進(jìn)行的。將一批料裝入300～400°F的模具中．在500磅／英寸2壓力下模塑。因用料廉價(jià)，所以原料成本低。不過(guò)由于在模塑過(guò)程中纖維的定向性降低了機(jī)械強(qiáng)度。
高速壓塑，即增強(qiáng)熱塑性塑料片材的沖壓，用途廣泛。玻璃氈片和聚丙烯相配合用于可沖壓的塑料，其循環(huán)周期低于40秒。生坯送至對(duì)流爐中加熱。加熱以后，毛坯放入壓塑模具中，這一過(guò)程用新的壓塑機(jī)速度可達(dá)1400英寸／分鐘。以75英寸／分鐘（比SMC的壓塑過(guò)程快約3倍）加壓進(jìn)料。根據(jù)市場(chǎng)的要求，有些新的可沖壓塑料，表面光潔度好，并且具有可涂布性。模塑壓力一般1噸／英寸2。傳統(tǒng)的壓塑工藝近幾年一直呈增長(zhǎng)的趨勢(shì)。在空間技術(shù)和國(guó)防方面的應(yīng)用正在使這種工藝向其難點(diǎn)沖擊。
在SMC、BMC、TMC、熱塑性片材的沖壓、增強(qiáng)材料的摻混和壓塑機(jī)械方面的發(fā)展迅速增長(zhǎng)，以適應(yīng)工業(yè)的新要求。
一些先進(jìn)的摻混料的壓塑主要是在空間技術(shù)和國(guó)防應(yīng)用方面發(fā)展迅速。工具和模具的新概念及高溫（達(dá)1200°F）模塑機(jī)，使石墨一碳纖維復(fù)合材料得以發(fā)展，代替了現(xiàn)有的金屬鑄件。
高溫硅樹脂正用作高壓介質(zhì)。復(fù)合材料做的片層用于壓塑模中?，F(xiàn)在，材料和生產(chǎn)成本已使該工藝更加適于空間技術(shù)市場(chǎng)，這類硅樹脂也很快轉(zhuǎn)向汽車領(lǐng)域。
壓鑄
在壓鑄工藝中，熱固性樹脂料加入一單獨(dú)的料腔，常叫料槽，然后強(qiáng)制送入一個(gè)或多個(gè)閉模中進(jìn)行聚合（固化）。
料道，也叫注道和流道，使物料從料槽流向模腔，進(jìn)入模腔之前經(jīng)過(guò)限流器或澆口。很多模腔具有單一料槽。料腔中的空氣被進(jìn)來(lái)的物料所置換，并通過(guò)一特別放置的排氣口排出。
當(dāng)物料置入料槽中時(shí)，在一緊湊的測(cè)量裝置中測(cè)料量，然后預(yù)熱到接近聚合溫度。一次只加入足夠一次的注塑量。
將預(yù)熱的原料送出料槽的力再將其送往一注料器，該注料器緊接裝在料槽上，以防止從活塞和料槽邊之間的縫隙中漏料。通常將密封套卡進(jìn)注料器以進(jìn)一步防漏。
料槽、注料器、澆口、流道和模腔的表面維持可使原料迅速固化的一定溫度，根據(jù)物料性質(zhì)、模具的設(shè)計(jì)和制件的幾何形狀該溫度為280～380°F。
在壓鑄物達(dá)到固化期的終點(diǎn)時(shí)，將該次完整的壓鑄物進(jìn)行脫模，包括脫除澆口、流道、注道和料槽中形成固化料墊（叫做殘料）。
在壓鑄中，物料的預(yù)熱很重要。冷料流動(dòng)緩慢，先進(jìn)入模腔的料尚未到其終點(diǎn)，即可能聚合。若發(fā)生上述情況，產(chǎn)品質(zhì)量低劣，不僅是外觀，也體現(xiàn)于機(jī)械性能。有些例外，如一次注射量很少，或一些低粘度的物料。可用加熱燈或爐子加熱，但有效而常用的方法是用專為塑料模塑制做的介電加熱器。
Plastic and pressure die casting process
In recent years, the pressure technique used in thermosetting plastic material
mixing ,such as urea-formaldehyde plastics, phenolic resin, epoxy rsin, melamine
resin and rubber. In spite of some of the material can be injection moiding, but the use of plastic pressure process is still very common. More pressure die casting material used plastic materials require more malleable soft. Many thermosetting materials with high impact level (1.0ft-1b) and good impact strength of maintaining the gap, only under ertreme pressure will flow.
Thermosetting plastic molding material pressure of the obvious advantages of the system is simple. Materials will be placed in a heating cavity, the pressure required by the Mission to time. As a result of the process simple, cost less. Enhancer and additive-free rules, and be able to get a better strength. As the gate and no runner ,not a waste of materials, die almost no maintenance. Parts of unity, and I cast no trace flow and reduce the cost of the modification. According to the structure and products used in the application of the characteristics of can be full-pressure die ,and die-pressure semi-closed mode (can be found in the plastic, plastic mold pressure related articles).
Equipment: The pressure is a simple plastic deices the main features . platen combination of the two and a half , heating, pressure, the shape of the target material. Most of the process of plastic used hydraulic pressure to operate; also used pneumatic operation .Tow board up and down under pressure in the 4 corner posts on moving up and down. According to the plastic device the size of the pressure, the pressure is generally 20-1000 tons. The general board for the 8-inch size 2-5 feet 2.
In addition, and after curing the release of different aspects of the degree of automation, the most commonly used modern hydraulic machine. The previous system , there is a simple temperature control, pressure control, pressure control and stop-time control. The use of modern equipment, advanced microprocessor control. For thinner products, in the board can be used in heating tube or belt heater. To the deeper parts, the need to use tube-shaped electric heater , heating steam or hot oil heating system. There are several types of plastic used in pressure in the heating system: uniform temperature steam heating mode, but the heating temperature is limited to below 350F;sleeve heating or other heating (heating coil, heating,ect.) relatively clean and easy maintenance, A more universal; thermal heating oil, heating due to the stability of the media cycle, the heat evenly. Now there are many new methods of heating ,hot water heating ,similar to the hot oil heating , water heating a medium for a gas combustion cycle , provides a greater degree of pressure temperature plastic.
Polymer modified to enhance rapid industrial development requires a new pressure to improve the plastic industry . Enhanced by two molded plastic mold: mold-yang (side mode) and the negative mold (cavity). When the mold is full of reinforcements, the mode of the hot mold closed two and a half, and then heated, pressurized product to be cured. Along the lines of big changes in the complexity of the mold can be used aluminum, plastic or steel do.
Light-weight materials making them less expensive, generally used for the production of short-term such as “cold-molding”.Coll at room temperature with molded resin, but the use of plastic mold and hydraulic pressure. The production of long-term use of hardened steel molds relatively cost-effective, the cut-off billet I can provide better performance and excellent cut finish. These steel pressure module on the use of machinery on the cut-off billet adapter I usually die together in the face area. This mode f metal molds, the products of its uniform surface, a good finish. Closed-mode technology used to pressure plastic molding,die-casting molding, injection and stamping some of the reinforced composites.
Some of the thermoplastic plastic materials can be molded plastic pressure, but in general or with pre-mixing of thermosetting resins such as BMC (prefabricated molding as a whole),SMC(film forming material molding),TMC(thick molding),film forming, such as carpet.
Carpet wet film forming sometimes called composite molding, in the hydraulic press will strengthen the role of materials and combined with resin. Often placed in the mold in carpet film will be dumped in to strengthen the resin material. Pressure in the process of cavity filled with resin to strengthen the material when fixed.
If there are serious parts of the alien or gradient, it is necessary to carry out pre-forming. Most of the film and felt pre-forming system in the projected area of the state’s need to 150-200 pounds/2 inch of mold pressure.
Pre-mixing materials, such as SMC, prepreg resin, filler, and the catalyst size enhance the material cut into a certain team sheet, and then adding the hot mold (in general 300-400 F), 1000-2000 1b/2 inch pressure Under the molding.
SMC for the relatively new plastic devices the pressure of the total cycle may be less than one minute (from start to finish). Has developed a special hydraulic device back in the bowl pressure machine, automatic control of the board level degrees.
Reinforced plastics, such as SMC, with a metal finish on molded plastic, tjis is very important parts of the surface. Sometimes occur in the processing of fibrous contraction.
Model with coating method could improve the surface finish. BMC pressure of the process of plastic is the oldest pre-mixing after one of the molding process. Filling materials (wood, mineral materials, such as celluiose) are mixed in mixing the leaves in the shap of the mixer. Will feed into a group of 300~400 F in the mold. In the 500-pound/2 inches under the pressure of molding. As a result of the use of materials for low-cost, the cost of raw materials. However, as in the molding process, the orientation of fiber reduces the mechanical strength.
Plastic high-speed pressure, that is, enhanced thermoplastic stamping the sheet, a wide range of uses. Felt piece of glass and polypropylene can be used to match the plastic stamping, the cycle less than 40 seconds. Green sent to the convection heating furnace. Heating, rough pressure into plastic molds, in the process with new pressure machine machine speed up to 1400 inches/minute. To 75 inches/minute (SMC than the pressure of plastic process about 3 times as fast) feed pressure. According to the requirements of the market, some of the new stamping plastics, surface finish, and can be coated with nature. I metric ton of pressure on the general molding/2 inch. Traditional plastic pressure technology in recent years has been on the rise. In the space technology for national defense and the application of this technology is difficult to shock.
In the SMC, BMC, TMC, the thermoplastic sheet stamping, reinforcement of the Blending plastic mechanical pressure and the development of the rapid growth of industry in order to meet the new requirements.
A number of advanced materials mixing plastic pressure mainly in space technology and applications in the rapid development of national defense. Tools and dies and the new concept of high-temperature (up to 1200 F) molding machine to make a graphite carbon fiber composite materials can be developed to replace the existing metal castings.
High temperature silicone is used as a high-pressure media. The composite sheet for the pressure in the mold. Now ,materials and production costs have made the process more suitable for space technology market, this type of silicone is also soon to the area of automobile.
In the die-casting process, thermosetting resin material is expected to join a separate chamber, often called trough, and then forced into one or more closed modules for polymerization(curing).
Liu, also known as Notes and the road runner, so that the flow of materials from the through cavity into the mold cavity before or after limiting gate. Many cavity with a single through. The air chamber is expected to be the replacement materials come in through a special place of the exhaust emissions.
When the materials placed in the trough, in a compact measuring device detected charge, and then warm-up to close to the polymerization temperature. Only by adding a sufficient amount of time the injection.
Preheat the raw materials will be sent trough of force and then a note sent to the feeder, the feeder note immediately installed in the trough, so as to prevent the pistons from the trough and gap between the edge of missing material. Taoka is usually closed to inject into the feeder to further leak-proof.
Trough, the note feeder, gate, runner and mold cavity on the surface of the material can maintain the rapid solidification of a certain temperature,according to the nature of the materials, mold design and parts of the temperature of 280~380 F.
In the die-casting material to reach the end of the curing period, the second-casting for a complete release, including the removal gate, runner and injecting Road in trough and the formation of curing pad material (called salvage).
In the die-casting, the warm-up material is very important. Cold expected to sloe the flow, first into the cavity of the material to its destination yet, that is likely to polymerization. If it happens, poor product quality, not just the appearance, but also in mechanical properties. Some exceptions, such as injecting a small amount, or some of the low viscosity of the material. Available light or heating stove heating, but an effective and commonly used method is used for making molded plastic dielectric heater.
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