手機(jī)后殼注塑模具設(shè)計(jì)【原版】
手機(jī)后殼注塑模具設(shè)計(jì)【原版】,原版,手機(jī),注塑,模具設(shè)計(jì)
畢業(yè)設(shè)計(jì)報(bào)告(論文)
報(bào)告(論文)題目：手機(jī)后殼注塑模具設(shè)計(jì)
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摘 要
本設(shè)計(jì)說(shuō)明書(shū)主要講述對(duì)手機(jī)后蓋進(jìn)行模具設(shè)計(jì)的過(guò)程。通過(guò)對(duì)塑件的工藝分析，設(shè)計(jì)出塑料模具。
本論文首先簡(jiǎn)單介紹了模具設(shè)計(jì)與分類(lèi)，然后對(duì)產(chǎn)品材料性能作了介紹，并初步選擇注射機(jī)。
本說(shuō)明書(shū)還詳細(xì)敘述了模具結(jié)構(gòu)方案，包括確定分型面、成型零部件的結(jié)構(gòu)設(shè)計(jì)、斜頂內(nèi)抽芯機(jī)構(gòu)、脫模機(jī)構(gòu)、合模導(dǎo)向機(jī)構(gòu)、冷卻系統(tǒng)等等的設(shè)計(jì)過(guò)程。還有重要零件的工藝參數(shù)的選擇與計(jì)算。校核注射模與注射機(jī)的關(guān)系等。
本設(shè)計(jì)主要是通過(guò)使用CAXA與AutoCAD完成裝配圖、零件圖。此次設(shè)計(jì)綜合了大學(xué)四年來(lái)所學(xué)的專(zhuān)業(yè)知識(shí)，從而進(jìn)一步鞏固了模具設(shè)計(jì)方面的相關(guān)知識(shí)，并積累了相關(guān)的設(shè)計(jì)意念與經(jīng)驗(yàn)。
The graduation project on the brochures of the main mobile phone back for the die design process. The plastic parts of the process, the design of a two-mode point of the plastic mold.
First of all, this paper a brief introduction of the mold design and classification, and then the product was introduced by the material properties, and the initial choice of injection machine.
This statement has also described in detail the structure of the program die, including the identification of sub-surface, forming the structural design of parts and components, core-pulling mechanism within Xieding, Stripping agencies Die-oriented institutions, and so on the cooling system design process. There is still an important part of the process parameters of choice and calculation. Check with the injection mold injection machines, such as the relationship.
This design is through the use of CAXA and AutoCAD completion of the assembly, parts map. The integrated design of a university graduate in three years the school's expertise to further consolidate the mold design-related knowledge, and the accumulation of related design ideas and experience.
關(guān)鍵詞：側(cè)抽芯 塑料模具 注射機(jī)
目錄
摘要
第一章、塑件結(jié)構(gòu)工藝分析與設(shè)計(jì)
1.1 材料的選用
1.2 脫模斜度
1.3 加強(qiáng)肋
1.4 塑件尺寸、公差與精度
1.5 壁厚
第二章、注射成型機(jī)的選擇
2.1 注射機(jī)的選用
2.2 鎖模力校核
第三章 、注射模的機(jī)構(gòu)設(shè)計(jì)
3.1 型腔數(shù)目的確定
3.2分型面的選擇
3.3澆注系統(tǒng)設(shè)計(jì)
3.3.1主流道設(shè)計(jì)
3.3.2分流道設(shè)計(jì)
3.3.3澆口的設(shè)計(jì)
3.4成型零件結(jié)構(gòu)設(shè)計(jì)
3.5排氣系統(tǒng)設(shè)計(jì)
第四章 、側(cè)抽芯機(jī)構(gòu)的設(shè)計(jì)
4.1 滑塊內(nèi)側(cè)分型抽芯機(jī)構(gòu)
4.2 抽芯距計(jì)算
第五章 、工作尺寸計(jì)算
5.1計(jì)算公式
5.2凹模的尺寸計(jì)算
5.3型芯的尺寸計(jì)算
第六章 、冷卻系統(tǒng)的設(shè)計(jì)與計(jì)算
第七章 、模具閉合高度的確定
結(jié)語(yǔ)
致謝
參考文獻(xiàn)
塑件的基本信息
材料：ABS+PC 公差等級(jí)：IT2 批量：大批量生產(chǎn)
第1章 塑件結(jié)構(gòu)工藝分析與設(shè)計(jì)
1.1 材料的選用
該塑件為手機(jī)后殼，要求具有一定的強(qiáng)度、剛度、耐熱和耐磨損等性能，同時(shí)還必須滿(mǎn)足絕緣性。
聚碳酸酯?透明度較高，沖擊韌性好，而且耐蠕變，使用溫度范圍廣，尺寸穩(wěn)定性好，電絕緣性?xún)?yōu)良，耐候性、無(wú)毒性。由于聚碳酸酯熔體粘度較高，在成型過(guò)程中極少發(fā)生泄漏現(xiàn)象。
ABS合成塑料以其具有很好的韌性( 抗震性) 、密封性，很高的機(jī)械強(qiáng)度，耐化學(xué)腐蝕，拿在手上很有質(zhì)感的特點(diǎn)而受到人們的青睞。有優(yōu)越的耐沖擊強(qiáng)度,特別是在低溫有無(wú)與倫比的沖擊強(qiáng)度,而且熱變形溫度高 。電性能,耐化學(xué)藥品性,耐油性好,易電鍍 。加工適應(yīng)性好,注射成型,擠出成型,模壓成型等所有的加工方法都可以,而且尺寸穩(wěn)定性好,耐堿性,耐應(yīng)力開(kāi)裂性也好
根據(jù)以上特點(diǎn)以及經(jīng)濟(jì)因素，采用ABS+PC塑料，規(guī)格性能如表1所示：
表1
代號(hào)
PC+ABS
比重
1.10—1.15
收縮率
0.004—0.006
熔融溫度
230—300℃
成型模溫
50—100℃
成型壓力
100—200Mpa
1.2 脫模斜度
設(shè)計(jì)脫模斜度的目的是便于塑件的脫模，避免在脫模過(guò)程中拉傷塑件表面，其大小取決于塑料的收縮率。脫模斜度的取向要根據(jù)塑件的內(nèi)外型尺寸而定。塑件外形以型腔大端為準(zhǔn)，尺寸要符合圖紙要求，斜度沿形狀減小方向。要求開(kāi)模后塑件留在型芯上，塑件內(nèi)表面的脫模斜度應(yīng)小于外表面的脫模斜度。根據(jù)ABS 和PC的性能，參考《實(shí)用模具設(shè)計(jì)簡(jiǎn)明手冊(cè)》表3—10，型芯和型腔的脫模斜度取1°。
1.3 加強(qiáng)肋
為了使塑件與底殼便于裝配，并有一定的強(qiáng)度和剛度，同時(shí)又能避免因壁過(guò)厚而產(chǎn)生成型缺陷，在塑件內(nèi)表面外側(cè)增設(shè)了多處加強(qiáng)肋。
1.4 塑件尺寸、公差與精度
該塑件長(zhǎng)64mm，寬42.6mm，最高8.5mm。影響塑件公差的主要因素是: 模具制造誤差及磨損誤差，尤其是成型零件的制造和裝配誤差以及使用中的磨損、塑料收縮的波動(dòng)、注射工藝條件的變化、塑件的形狀和飛邊厚度的波動(dòng)、脫模斜度及成型后塑件的尺寸變化。該塑件選用尺寸精度等級(jí)為MT2，公差為GB/T14486——1993 尺寸公差數(shù)值。
1.5 壁厚
由于產(chǎn)品的壁厚與熔體的流動(dòng)長(zhǎng)度、 生產(chǎn)效率以及使用要求等有關(guān)， 從成本和生產(chǎn)效率來(lái)看， 產(chǎn)品壁厚過(guò)厚也是不可取的，它不僅會(huì)增加制品的成本，而且成型周期也較長(zhǎng)， 所得制品的收縮率明顯增加。 因此，產(chǎn)品壁厚均為1.3mm，銜接部分的上下唇壁厚為0.3mm。
第2章 注射成型機(jī)的選擇
在模具設(shè)計(jì)時(shí)，根據(jù)產(chǎn)品幾何尺寸及模具結(jié)構(gòu)特點(diǎn)，盡可能選用適合的注塑機(jī)以充分發(fā)揮設(shè)備的內(nèi)在能力。從模具設(shè)計(jì)角度考慮，需要了解注射機(jī)的主要技術(shù)規(guī)范有：額定注射量、額定注射壓、額定鎖模力、模具安裝尺寸以及開(kāi)模行程等。
2.1 注射機(jī)的選用
根據(jù)塑件的體積或重量大致確定模具的結(jié)構(gòu)，初步確定注塑機(jī)的型號(hào)。根據(jù)手機(jī)殼的造型尺寸64x42.57x8.5mm，按注塑機(jī)加工能力和注塑量分類(lèi)選用小型注塑機(jī)，型號(hào)選用XS-Z-60，其相關(guān)參數(shù)如表：
螺桿直徑（mm）
28
模具最大厚度（mm）
200
拉桿內(nèi)間距（HxVmm）
190*300
注射時(shí)間（s）
20
標(biāo)稱(chēng)注塑容量（c）
60
高壓時(shí)間（s）
3
注塑壓力（MPa）
122
冷卻時(shí)間（s）
20
注塑速率（g/s）
120
噴嘴溫度（0C）
200
鎖模力（kN）
500
模具溫度（0C）
80
模具最小厚度（mm）
70
模板最大行程（mm）
180
2.2 鎖模力校核
鎖模力是指注射機(jī)構(gòu)在工作中對(duì)模具所能施加的最大夾緊力。鎖模力與注射容量全面地反映了設(shè)備的主要特征和加工能力。
在實(shí)際注射成型中，由于制品形狀不同，所采用樹(shù)脂品種不同，注射工藝條件及模具結(jié)構(gòu)不同，所需要的合模力大小也各不相同。因此，在選用注射機(jī)時(shí),要對(duì)其合模力進(jìn)行計(jì)算。通常，可采用下列公式進(jìn)行：
F≥Pm(NAs+Aj)
式中: F-----注射機(jī)最大合模力(MN)
N------型腔個(gè)數(shù)
Pc----成型時(shí)型腔平均壓力（MPa）
As-----塑件在開(kāi)模方向的最大投影面積(㎡)
Aj-----澆注系統(tǒng)在開(kāi)模方向的最大投影面積(㎡)
從前面可知: N=2
計(jì)算得澆注系統(tǒng)以及塑件在開(kāi)模方向上的投影面積約為：
0.064×0.042×2+0.08×0.006=0.005856㎡．
所以： F≥nPcA
=2×30×0.005856
=0.3514MN
=351.4KN
而注塑機(jī)合模力500KN>351.4KN，故滿(mǎn)足要求。
第3章 注射模的結(jié)構(gòu)設(shè)計(jì)
3.1 型腔數(shù)目的確定
型腔數(shù)目的確定，應(yīng)根據(jù)塑件的幾何形狀及尺寸、質(zhì)量要求、批量大小、交貨期長(zhǎng)短、注射機(jī)能力、模具成本等要求來(lái)綜合考慮。根據(jù)塑件質(zhì)量要求，大型、中型、復(fù)雜塑件一般都采用單型腔注射模，而高精度塑件的型腔數(shù)原則上不超過(guò)4個(gè)，本模具型腔數(shù)采用一模兩腔。
3.2 分型面的設(shè)計(jì)
如何確定分型面，需要考慮的因素比較復(fù)雜。由于分型面受到塑件在模具中的成型位置、澆注系統(tǒng)設(shè)計(jì)、塑件的結(jié)構(gòu)工藝性及精度、嵌件位置形狀以及推出方法、模具的制造、排氣、操作工藝等多種因素的影響，因此在選擇分型面時(shí)應(yīng)綜合分析比較，從幾種方案中優(yōu)選出較為合理的方案。選擇分型面時(shí)一般應(yīng)遵循以下幾項(xiàng)原則：
1、分型面應(yīng)選在塑件外形最大輪廓處。
2、便于塑件順利脫模，盡量使塑件開(kāi)模時(shí)留在動(dòng)模一邊。
3、保證塑件的精度要求。
4、滿(mǎn)足塑件的外觀質(zhì)量要求。
5、便于模具加工制造。
6、對(duì)成型面積的影響。
7、對(duì)排氣效果的影響。
8、對(duì)側(cè)向抽芯的影響。
綜上分型面選手機(jī)蓋底平面為分型面。
3.3澆注系統(tǒng)設(shè)計(jì)
3.3.1主流道設(shè)計(jì)
我的設(shè)計(jì)采用直澆口式主流道，如圖1所示：主流道入口直徑d應(yīng)大于注射機(jī)噴嘴直徑1mm左右。這樣便于兩者能同軸對(duì)準(zhǔn)，也使得主流道凝料能順利脫出。所以：
d =4+1=5mm
主流道入口的凹坑球面半徑R，應(yīng)該大于注射機(jī)噴嘴球頭半徑約2～3mm。反之，兩者不能很好貼和，會(huì)讓塑料熔體反噴，出現(xiàn)溢邊致使脫模困難。故：
R=15+（2～3）=（17～18）mm
取R=18mm
錐孔壁粗糙度Ra≤0.8μm，取Ra0.63μm。主流道的錐角α=2°～4°。過(guò)大的錐角會(huì)產(chǎn)生湍流或渦流，卷入空氣。過(guò)小錐角使凝料脫模困難，還會(huì)使充模時(shí)流動(dòng)阻力大，比表面增大，熱量損耗大。這里取2°。主流道的出口端應(yīng)該有較大圓角r≈ D。
其中， D可用經(jīng)驗(yàn)公式求出：
D=
其中， V----流經(jīng)主流道的熔體體積（c）；
K----因熔體材料而異的常數(shù)，取K=1.2；
所以， D==≈ 4.6mm
所以， r===0.58mm，這里取r=1mm
主流道的長(zhǎng)度是L，一般按模板厚度確定。但為了減小充模時(shí)壓力降和減少物料損耗，以短為好。小模具控制在60mm之內(nèi)。初步確定：
L=50mm
3.3.2 分流道設(shè)計(jì)
分流道的截面形狀有圓形、半圓形、矩形、梯形、V形等多種。其中圓形截面最理想，使用越來(lái)越多。本次設(shè)計(jì)采用單面圓形截面。
3.3.3 澆口設(shè)計(jì)
模具設(shè)計(jì)時(shí)，澆口的位置及尺寸要求比較嚴(yán)格，初步試模后還需進(jìn)一步修改澆口尺寸，無(wú)論采用何種澆口，其開(kāi)設(shè)位置對(duì)塑件成型性能及質(zhì)量影響很大，因此合理選擇澆口的開(kāi)設(shè)位置是提高質(zhì)量的重要環(huán)節(jié)，同時(shí)澆口位置的不同還影響模具結(jié)構(gòu)?？傊顾芗哂辛己玫男阅芘c外表，一定要認(rèn)真考慮澆口位置的選擇， 綜合我的塑件，是比較容易流動(dòng)的ABS和PC，而且零件外表面要求較高；我設(shè)計(jì)的澆口位置在手機(jī)后殼的底側(cè)。
3.4 成型零件結(jié)構(gòu)設(shè)計(jì)
3.4.1 定模結(jié)構(gòu)設(shè)計(jì)
定模是成型塑件外表面的成型零件。定模的基本結(jié)構(gòu)可分為整體式、整體潛入式和組合式。根據(jù)本次設(shè)計(jì)的塑料的特點(diǎn)，采用整體式定模。
3.4.2 動(dòng)模結(jié)構(gòu)設(shè)計(jì)
動(dòng)模和和動(dòng)模型芯都是用來(lái)成型塑料制品的內(nèi)表面的成型零件。動(dòng)模也稱(chēng)主型芯，用來(lái)成型塑件整體的內(nèi)部形狀。與定模部分不同，它與注塑機(jī)后半部分相連它參于塑件的頂出，一般的模具設(shè)計(jì)都要求塑件留在動(dòng)模部分，好容易脫模。因而動(dòng)模一般比定模復(fù)雜。
我的塑件由于外表面向上，要求較高，而內(nèi)表面裝配在手機(jī)里面，對(duì)于外觀并沒(méi)有太高的要求，所以只要保證尺寸的精確就可以了。經(jīng)過(guò)查資料和考證，我采用與定模部分一樣的結(jié)構(gòu)——整體凸模。
3.5 排氣系統(tǒng)的設(shè)計(jì)
由于我的設(shè)計(jì)采用了大量的推桿以實(shí)現(xiàn)模具對(duì)塑件的均勻頂出，使得塑件不會(huì)因?yàn)閼?yīng)力不均勻而斷裂或留下痕跡；采用了滑塊來(lái)實(shí)現(xiàn)塑件的抽芯。這些結(jié)構(gòu)都的存在著間隙，可以利用這些間隙實(shí)現(xiàn)排氣的功能，而不用設(shè)計(jì)另外的排氣結(jié)構(gòu)。
第4章 抽芯機(jī)構(gòu)設(shè)計(jì)
4.1 滑塊內(nèi)側(cè)分型抽芯機(jī)構(gòu)
由于本塑件結(jié)構(gòu)的特殊性，塑件的成型機(jī)構(gòu)大部分也就是抽芯機(jī)構(gòu)。本模具滑塊設(shè)計(jì)如下圖
4.2 抽芯距計(jì)算
S=S1+2～3
S1——側(cè)成型零件成型位置點(diǎn)與不防礙塑件軸向推出之極限相關(guān)點(diǎn)間的距離（mm）
所以 S=2+2～3=4～5mm
第5章 工作尺寸計(jì)算
按照以上規(guī)定，現(xiàn)根據(jù)塑料件的尺寸按平均收縮率對(duì)模具尺寸進(jìn)行計(jì)算。其中，我們由第一章可知，=0.5％, 塑件尺寸為長(zhǎng)64mm，寬42.75mm，最高8.5mm。
本節(jié)所采用的主要代號(hào)及其含義如下：
——成型零件工作尺寸（mm）
——注射塑料的平均成型收縮率（%）
——塑件基本尺寸（mm）
----塑件公差值（mm）
——成型零件制造公差（mm）,其值取/6～/3。當(dāng)成型大型塑件時(shí)，取偏下限；當(dāng)成型小
塑件或采用組合式型芯與凹模時(shí)，取偏上限。
5.1 計(jì)算公式
凹模徑向尺寸：L=[(1+S)L-3/4Δ]；按增大凹模徑向尺寸修模
型芯徑向尺寸：L=( L＋LS+0.75Δ)
凹模深度尺寸：H=[H（1+S)-2/3Δ]
型芯高度尺寸：H=(H＋HS+2/3Δ)
5.2 凹模工作尺寸計(jì)算
由公式L=[(1+S)L-3/4Δ]
L1=(1.005*64-0.75*0.34)=64.065
L2=(1,.005*42.75-0.75*0.26)=42.769
由公式H=[H（1+S)-2/3Δ]
H=(1.005*8.5-2/3*0.14)=8.45
5.3 型芯工作尺寸計(jì)算
由公式L=( L＋LS+0.75Δ)
L1=(1.005*61.4+0.75*0.34)=61.96
L2=(1.005*40.15+0.75*0.26)=40.55
由公式H=(H＋HS+2/3Δ)
H=(1.005*7.2+2/3*0.14)=7.33
第6章 冷卻系統(tǒng)的設(shè)計(jì)
管道直徑經(jīng)湍流計(jì)算確定，一般取d=8～12mm。 PC和ABS的注射成型特性是低料溫，高壓力注射。模具型腔復(fù)雜，實(shí)在不易采用較大的管道直徑，以免影響到斜滑頂桿、推桿推出塑件。Ф8的管道已經(jīng)能夠保證注塑過(guò)程中的能量轉(zhuǎn)換。因此冷卻系統(tǒng)的管道設(shè)為Ф8。位置如圖
第7章 模具閉合高度的確定
尺寸組合B×L ： 200×230
定模板厚度為： 40mm
定模座板厚度為： 20mm
動(dòng)模座板厚度為： 20mm
動(dòng)模板厚度為： 40mm
墊塊厚度為： 60mm
模具總厚度為： 180mm
結(jié) 語(yǔ)
通過(guò)本次設(shè)計(jì)，使我對(duì)大學(xué)階段所學(xué)習(xí)的模具設(shè)計(jì)方面的知識(shí)做了一個(gè)很好的總結(jié)和鞏固，平時(shí)所學(xué)的比較零散的知識(shí)得到了系統(tǒng)化的運(yùn)用。發(fā)現(xiàn)了自己在學(xué)科內(nèi)的某些方面知識(shí)的欠缺。在模具設(shè)計(jì)中，我越往下做就越感覺(jué)到自己知識(shí)的淺薄，我發(fā)現(xiàn)模具設(shè)計(jì)需要考慮的問(wèn)題總比我想到的要多。
做完本次設(shè)計(jì)，我強(qiáng)烈的希望自己盡快的走上工作崗位，因?yàn)槲疑钌畹母杏X(jué)到實(shí)際經(jīng)驗(yàn)的匱乏對(duì)模具設(shè)計(jì)有多么大的影響。因?yàn)閷?duì)整個(gè)模具設(shè)計(jì)缺乏大局感和立體感，在整個(gè)設(shè)計(jì)中往往感到捉襟見(jiàn)肘，整個(gè)的設(shè)計(jì)還是在別人設(shè)計(jì)的框架下完成的，缺乏了一種思維的創(chuàng)新和跳躍。
在本次設(shè)計(jì)中，我使用了UG、CAD等輔助軟件，尤其是CAD，通過(guò)這次設(shè)計(jì)我對(duì)CAD的操作更加熟練了。在設(shè)計(jì)中，我翻閱了大量的書(shū)籍，公差、制圖、力學(xué)、材料，在這次設(shè)計(jì)中都用到了。
通過(guò)本次設(shè)計(jì)，對(duì)模具的設(shè)計(jì)和加工有了一個(gè)比較系統(tǒng)、全面的認(rèn)識(shí)和了解，同時(shí)也遇到了很多問(wèn)題。在學(xué)校老師和同學(xué)們的指導(dǎo)幫助下，設(shè)計(jì)終于成功的完成了，從如何選材到確定大致模架結(jié)構(gòu)，從零件圖的繪制再到說(shuō)明書(shū)的裝訂，包含了太多的汗水，也為這大學(xué)4年畫(huà)上了一個(gè)完美的句號(hào)。
致謝
首先，我要衷心感謝我的指導(dǎo)老師-任兆坤老師！在設(shè)計(jì)過(guò)程中給與我的幫助與指正，老師經(jīng)常詢(xún)問(wèn)我的進(jìn)度，并督促我盡快完成。同時(shí)，我要感謝同組同學(xué)的幫助，在我遇到不懂的問(wèn)題時(shí)，及時(shí)幫助我克服。在此對(duì)給予幫助的老師們及同學(xué)們表示真摯的感謝。
由于我設(shè)計(jì)水平有限，設(shè)計(jì)中肯定會(huì)有許多不足之處，敬請(qǐng)各位老師批評(píng)指正。
參考文獻(xiàn)
[1]機(jī)械設(shè)計(jì)手冊(cè)編委會(huì). 機(jī)械設(shè)計(jì)手冊(cè)（單行本?齒輪傳動(dòng)）——4版 . 北京:機(jī)械工業(yè)出版社，2007.3
[2]郁文娟，顧 燕. 塑料產(chǎn)品工業(yè)設(shè)計(jì)基礎(chǔ).北京：化學(xué)工業(yè)出版社，2006. 9
[3]王建華，徐佩弦. 注射模的熱流道技術(shù). 北京：機(jī)械工業(yè)出版社，2005.11
[4]王文廣，田寶善等. 塑料注射模具設(shè)計(jì)技巧與實(shí)例. 北京：化學(xué)工業(yè)出版社， 2003. 12
[5] 奇曉杰. 塑料成型工藝與模具設(shè)計(jì). 北京: 機(jī)械工業(yè)出版社, 2005.10
[6] 趙偉閣. 模具設(shè)計(jì). 西安: 電子科技大學(xué)出版社, 2006.8
[7] 劉靖巖. 模具設(shè)計(jì)與制造. 北京: 中國(guó)輕工業(yè)出版社, 2005.9
14
Journal of Materials Processing Technology 187188(2007)690693Adaptive system for electrically driven thermoregulationof moulds for injection mouldingB.Nardina,B.Zagara,A.Glojeka,D.Kri zajbaTECOS,Tool and Die Development Centre of Slovenia,Kidri ceva Cesta 25,3000 Celje,SloveniabFaculty of Electrical Engineering,Ljubljana,SloveniaAbstractOne of the basic problems in the development and production process of moulds for injection moulding is the control of temperature con-ditions in the mould.Precise study of thermodynamic processes in moulds showed,that heat exchange can be manipulated by thermoelectricalmeans.Such system upgrades conventional cooling systems within the mould or can be a stand alone application for heat manipulation withinit.Inthepaper,theauthorswillpresentresultsoftheresearchproject,whichwascarriedoutinthreephasesanditsresultsarepatentedinA6862006patent.The testing stage,the prototype stage and the industrialization phase will be presented.The main results of the project were total and rapidon-line thermoregulation of the mould over the cycle time and overall influence on quality of plastic product with emphasis on deformationcontrol.Presentedapplicationcanpresentamilestoneinthefieldofmouldtemperatureandproductqualitycontrolduringtheinjectionmouldingprocess.2006 Elsevier B.V.All rights reserved.Keywords:Injection moulding;Mould cooling;Thermoelectric modules;FEM simulations1.Introduction,definition of problemDevelopment of technology of cooling moulds via thermo-electrical(TEM)means derives out of the industrial praxis andproblems,i.e.at design,tool making and exploitation of tools.Current cooling technologies have technological limitations.Their limitations can be located and predicted in advance withfiniteelementanalyses(FEA)simulationpackagesbutnotcom-pletely avoided.Results of a diverse state of the art analysesrevealed that all existing cooling systems do not provide con-trollable heat transfer capabilities adequate to fit into demand-ing technological windows of current polymer processingtechnologies.Polymer processing is nowadays limited(in term of short-ening the production cycle time and within that reducing costs)onlywithheatcapacitymanipulationcapabilities.Otherproduc-tion optimization capabilities are already driven to mechanicaland polymer processing limitations 3.Corresponding authors.Tel.:+386 3 490920;fax:+386 3 4264612.E-mail address:Blaz.Nardintecos.si(B.Nardin).1.1.Thermal processes in injection moulding plasticprocessingPlastic processing is based on heat transfer between plasticmaterial and mould cavity.Within calculation of heat transferone should consider two major facts:first is all used energywhich is based on first law of thermodynamicslaw of energyconservation 1,second is velocity of heat transfer.Basic taskat heat transfer analyses is temperature calculation over timeand its distribution inside studied system.That last depends onvelocity of heat transfer between the system and surroundingsand velocity of heat transfer inside the system.Heat transfer canbe based as heat conduction,convection and radiation 1.1.2.Cooling timeComplete injection moulding process cycle comprises ofmouldclosingphase,injectionofmeltintocavity,packingpres-sure phase for compensating shrinkage effect,cooling phase,mould opening phase and part ejection phase.In most cases,thelongest time of all phases described above is cooling time.Cooling time in injection moulding process is defined astime needed to cool down the plastic part down to ejectiontemperature 1.0924-0136/$see front matter 2006 Elsevier B.V.All rights reserved.doi:10.1016/j.jmatprotec.2006.11.052B.Nardin et al./Journal of Materials Processing Technology 187188(2007)690693691Fig.1.Mould temperature variation across one cycle 2.The main aim of a cooling process is to lower additionalcoolingtimewhichistheoreticallyneedless;inpraxis,itextendsfrom 45 up to 67%of the whole cycle time 1,4.From literature and experiments 1,4,it can be seen,that themould temperature has enormous influence on the ejection timeand therefore the cooling time(costs).Injection moulding process is a cyclic process where mouldtemperature varies as shown in Fig.1 where temperature variesfrom average value through whole cycle time.2.Cooling technology for plastic injection mouldsAs it was already described,there are already several differ-ent technologies,enabling the users to cool the moulds 5.Themost conventional is the method with the drilling technology,i.e.producing holes in the mould.Through these holes(coolinglines),thecoolingmediaisflowing,removingthegeneratedandaccumulatedheatfromthemould1,2.Itisalsoveryconvenientto build in different materials,with different thermal conductiv-ity with the aim to enhance control over temperature conditionsin the mould.Such approaches are so called passive approachestowards the mould temperature control.The challenging task is to make an active system,which canalter the thermal conditions,regarding to the desired aspects,like product quality or cycles time.One of such approaches isintegrating thermal electrical modules(TEM),which can alterthe thermal conditions in the mould,regarding the desired prop-erties.With such approach,the one can control the heat transferwith the time and space variable,what means,that the temper-ature can be regulated throughout the injection moulding cycle,independent of the position in the mould.The heat control isdone by the control unit,where the input variables are receivedfrom the manual input or the input from the injection mouldingsimulation.With the output values,the control unit monitors theTEM module behaviour.2.1.Thermoelectric modules(TEM)For the needs of the thermal manipulation,the TEM modulewasintegratedintomould.Interactionbetweentheheatandelec-trical variables for heat exchange is based on the Peltier effect.The phenomenon of Peltier effect is well known,but it was untilFig.2.TEM block diagram.now never used in the injection moulding applications.TEMmodule(see Fig.2)is a device composed of properly arrangedpairsofPandNtypesemiconductorsthatarepositionedbetweentwo ceramic plates forming the hot and the cold thermoelectriccooler sites.Power of a heat transfer can be easily controlledthrough the magnitude and the polarity of the supplied electriccurrent.2.2.Application for mould coolingThe main idea of the application is inserting TEM moduleinto walls of the mould cavity serving as a primary heat transferunit.Such basic assembly can be seen in Fig.3.Secondary heattransfer is realized via conventional fluid cooling system thatallows heat flows in and out from mould cavity thermodynamicsystem.Device presented in Fig.3 comprises of thermoelectricmodules(A)that enable primarily heat transfer from or to tem-perature controllable surface of mould cavity(B).Secondaryheat transfer is enabled via cooling channels(C)that deliverconstant temperature conditions inside the mould.Thermoelec-tric modules(A)operate as heat pump and as such manipulatewith heat derived to or from the mould by fluid cooling sys-tem(C).System for secondary heat manipulation with coolingchannels work as heat exchanger.To reduce heat capacity ofcontrollable area thermal insulation(D)is installed between themould cavity(F)and the mould structure plates(E).Fig.3.Structure of TEM cooling assembly.692B.Nardin et al./Journal of Materials Processing Technology 187188(2007)690693Fig.4.Structure for temperature detection and regulation.The whole application consists of TEM modules,a temper-ature sensor and an electronic unit that controls the completesystem.The system is described in Fig.4 and comprises of aninput unit(input interface)and a supply unit(unit for electronicand power electronic supplyH bridge unit).The input and supply units with the temperature sensor loopinformation are attached to a control unit that acts as an exe-cution unit trying to impose predefined temperate/time/positionrelations.UsingthePeltiereffect,theunitcanbeusedforheatingor cooling purposes.The secondary heat removal is realized via fluid coolingmedia seen as heat exchanger in Fig.4.That unit is based oncurrent cooling technologies and serves as a sink or a sourceof a heat.This enables complete control of processes in termsof temperature,time and position through the whole cycle.Furthermore,it allows various temperature/time/position pro-files within the cycle also for starting and ending procedures.Described technology can be used for various industrial andresearchpurposeswhereprecisetemperature/time/positioncon-trol is required.ThepresentedsystemsinFigs.3and4wereanalysedfromthetheoretical,aswellasthepracticalpointofview.ThetheoreticalaspectwasanalysedbytheFEMsimulations,whilethepracticalonebythedevelopmentandtheimplementationoftheprototypeinto real application testing.3.FEM analysis of mould coolingCurrent development of designing moulds for injectionmoulding comprises of several phases 3.Among them is alsodesign and optimization of a cooling system.This is nowa-daysperformedbysimulationsusingcustomizedFEMpackages(Moldflow 4)that can predict cooling system capabilities andespeciallyitsinfluenceonplastic.Withsuchsimulations,moulddesigners gather information on product rheology and deforma-tionduetoshrinkageasellasproductiontimecycleinformation.This thermal information is usually accurate but can still beunreliable in cases of insufficient rheological material informa-tion.For the high quality input for the thermal regulation ofTEM,it is needed to get a picture about the temperature distri-bution during the cycle time and throughout the mould surfaceandthroughoutthemouldthickness.Therefore,differentprocesssimulations are needed.Fig.5.Cross-section of a prototype in FEM environment.3.1.Physical model,FEM analysisImplementation of FEM analyses into development projectwas done due to authors long experiences with such packages4 and possibility to perform different test in the virtual envi-ronment.WholeprototypecoolingsystemwasdesignedinFEMenvironment(seeFig.5)throughwhichtemperaturedistributionin each part of prototype cooling system and contacts betweenthem were explored.For simulating physical properties inside adeveloped prototype,a simulation model was constructed usingCOMSOL Multiphysics software.Result was a FEM modelidentical to real prototype(see Fig.7)through which it waspossible to compare and evaluate results.FEM model was explored in term of heat transfer physicstaking into account two heat sources:a water exchanger withfluid physics and a thermoelectric module with heat transferphysics(onlyconductionandconvectionwasanalysed,radiationwas ignored due to low relative temperature and therefore lowimpact on temperature).Boundary conditions for FEM analyses were set with thegoal to achieve identical working conditions as in real test-ing.Surrounding air and the water exchanger were set at stabletemperature of 20C.Fig.6.Temperature distribution according to FEM analysis.B.Nardin et al./Journal of Materials Processing Technology 187188(2007)690693693Fig.7.Prototype in real environment.ResultsoftheFEManalysiscanbeseeninFig.6,i.e.temper-ature distribution through the simulation area shown in Fig.5.Fig.6 represents steady state analysis which was very accuratein comparison to prototype tests.In order to simulate the timeresponse also the transient simulation was performed,showingverypositiveresultsforfuturework.Itwaspossibletoachieveatemperature difference of 200C in a short period of time(5s),what could cause several problems in the TEM structure.Thoseproblems were solved by several solutions,such as adequatemounting,choosing appropriate TEM material and applyingintelligent electronic regulation.3.2.Laboratory testingAs it was already described,the prototype was produced andtested(see Fig.7).The results are showing,that the set assump-tions were confirmed.With the TEM module it is possible tocontrol the temperature distribution on different parts of themould throughout the cycle time.With the laboratory tests,itwas proven,that the heat manipulation can be practically regu-lated with TEM modules.The test were made in the laboratory,simulating the real industrial environment,with the injectionmoulding machine Krauss Maffei KM 60 C,temperature sen-sors,infrared cameras and the prototype TEM modules.Thetemperature response in 1.8s varied form+5 up to 80C,whatrepresents a wide area for the heat control within the injectionmoulding cycle.4.ConclusionsUse of thermoelectric module with its straightforward con-nection between the input and output relations represents amilestone in cooling applications.Its introduction into mouldsforinjectionmouldingwithitsproblematiccoolingconstructionand problematic processing of precise and high quality plasticparts represents high expectations.The authors were assuming that the use of the Peltier effectcan be used for the temperature control in moulds for injectionmoulding.With the approach based on the simulation work andtherealproductionoflaboratoryequipmentproved,theassump-tions were confirmed.Simulation results showed a wide area ofpossible application of TEM module in the injection mouldingprocess.With mentioned functionality of a temperature profile acrosscycle time,injection moulding process can be fully controlled.Industrial problems,such as uniform cooling of problematicA class surfaces and its consequence of plastic part appear-ance can be solved.Problems of filling thin long walls can besolvedwithoverheatingsomesurfacesatinjectiontime.Further-more,with such application control over rheological propertiesof plastic materials can be gained.With the proper thermalregulation of TEM it was possible even to control the meltflow in the mould,during the filling stage of the mould cav-ity.This is done with the appropriate temperature distributionof the mould(higher temperature on the thin walled parts of theproduct).With the application of TEM module,it is possible to signif-icantly reduce the cycle time in the injection moulding process.Thelimitsofpossibletimereductionliesintheframeof1025%of additional cooling time,describe in Section 1.2.With the application of TEM module it is possible to activelycontrol the warping of the product and to regulate the amountof product warpage in the way to achieve required product tol-erances.ThepresentedTEMmodulecoolingapplicationforinjectionmoulding process is a matter of priority note for the patent,heldand owned by TECOS.References1 I.Cati c,Izmjena topline u kalupima za injekcijsko pre sanje plastomera,Dru stvo plasti cara i gumaraca,Zagreb,1985.2 I.Cati c,F.Johannaber,Injekcijsko pre sanje polimera i ostalih materiala,Dru stvo za plastiku i gumu,Biblioteka polimerstvo,Zagreb,2004.3 B.Nardin,K.Kuzman,Z.Kampu s,Injection moulding simulation resultsas an input to the injection moulding process,in:AFDM 2002:The Sec-ondInternationalConferenceonAdvancedFormingandDieManufacturingTechnology,Pusan,Korea,2002.4 TECOS,SlovenianToolandDieDevelopmentCentre,MoldflowSimulationProjects 19962006.5 S.C.Chen,et al.,Rapid mold surface heating/cooling using electromag-netic induction technology:ANTEC 2004,Conference CD-ROM,Chicago,Illinois,1620 May,2004.
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