加熱器底座塑料模具設(shè)計(jì)-注塑模具【三維PROE零件圖】
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致謝
題目：加熱器底座塑料模具設(shè)計(jì)
系 別： 機(jī)電信息系
專(zhuān) 業(yè)：機(jī)械設(shè)計(jì)制造及其自動(dòng)化
班 級(jí)：
學(xué) 生：
學(xué) 號(hào)：
指導(dǎo)教師：
2013年04月
塑料注塑模具設(shè)計(jì)——加熱器底座塑料模具設(shè)計(jì)
摘 要
模具是工業(yè)生產(chǎn)中使用極為廣泛的主要工藝裝備，它是當(dāng)代工業(yè)生產(chǎn)的重要手段和工藝發(fā)展方向，許多現(xiàn)代工業(yè)的發(fā)展和技術(shù)水平的提高，在很大程度上取決于模具工業(yè)的發(fā)展水平。本論文主要介紹了加熱器底座塑料注塑模具的設(shè)計(jì)。
設(shè)計(jì)中首先通過(guò)分析塑件的形狀及工藝特性，選擇了合適的模具設(shè)計(jì)方案；其次是對(duì)注塑機(jī)的選擇，包括注射機(jī)的初選和注射機(jī)有關(guān)參數(shù)的校核，并確定了注射機(jī)；再次完成模具的結(jié)構(gòu)設(shè)計(jì)，包括分型面的選擇和確定、型腔數(shù)目的確定及型腔的排列、澆注系統(tǒng)的設(shè)計(jì)、成型零件結(jié)構(gòu)設(shè)計(jì)、抽芯機(jī)構(gòu)設(shè)計(jì)、推出機(jī)構(gòu)的選擇、冷卻系統(tǒng)的設(shè)計(jì)、標(biāo)準(zhǔn)模架的選擇。最后對(duì)成型零件尺寸進(jìn)行計(jì)算，確定工藝參數(shù)。
采用此模具能夠保證塑件尺寸外形以及表面要求，而且成本低、結(jié)構(gòu)簡(jiǎn)單、開(kāi)模容易、效率高，具有較強(qiáng)的實(shí)用性。
關(guān)鍵詞：塑料注塑模具；注塑機(jī)；結(jié)構(gòu)設(shè)計(jì)
Plastic Injection Mold Design Heater Base Plastic Mold Design
Abstract
Mold is widely used in industrial production the main technological equipment, It is an important means of modern industrial production and process development direction ,Many modern industrial development and the improvement of the technical levels ,Largely depends on the development of die and mould industry level. This paper mainly introduced the plastic injection mold insurance seat of design.
First through analysis in the design of plastic parts, process characteristics and shape ,choose the proper mould design,Second is the choice of injection, mcluding injection machine of primaries and injection machine related parameter respectively ,To determine the injection machine；Complete the die structure design again ,Enclose the choice and determination parting ,Cavity number of determining and cavity arrangement ,The design of gating system ,Molding parts structure design ,Core-pulling mechanism design, selection of launch institutions, cooling system design, standard formwork choice ,Finally calculated for molding parts size, determine the process parameters.
Using this mold can guarantee plastics dimension appearance and surface requirements , And low cost, simple structure and easy to open mold, high efficiency, with strong practicability.
Keywords: Plastic injection mold; injection machine; Structure design
II
主要符號(hào)表
K 安全系數(shù) E 材料彈性模量
Smax 塑料的最大收縮率 P1 脫模阻力
Smin 塑料的最小收縮率 C 型芯成型部分?jǐn)嗝娴钠骄?
P0 單位面積的包緊力 h 型芯被塑料包緊部分的長(zhǎng)度
Δs 塑件公差 P0 單位面積的包緊力
D腔 型腔內(nèi)形尺寸 Φ 安全系數(shù)
Qcp 塑料平均收縮率 S頂 頂出行程
ds 塑件外徑基本尺寸 1 富裕量
Ds 塑件內(nèi)形基本尺寸 2 頂出行程富裕量
h腔 凸模/型芯高度尺寸 α 傾斜角
Hs 塑件內(nèi)形深度基本尺寸 Q 抽拔阻力
P1 動(dòng)模受的總壓力 P 斜導(dǎo)柱所受的彎曲力
F 塑件的投影面積 ε 塑件收縮率
P 型腔壓力 f 摩擦系數(shù)
K 修正系數(shù) μ 塑料泊桑比
B 動(dòng)模墊板的寬度 L 支撐塊的跨距
目 錄
1 緒論 1
1.1塑料成型與注塑模具 1
1.2國(guó)內(nèi)外相關(guān)發(fā)展?fàn)顩r 1
1.2.1國(guó)內(nèi)發(fā)展?fàn)顩r 1
1.2.2國(guó)外發(fā)展?fàn)顩r 2
1.2.3中國(guó)與國(guó)外先進(jìn)技術(shù)的差距 2
1.3塑料模具發(fā)展走勢(shì) 2
2 塑件材料分析與方案論證 3
2.1塑件的工藝分析 3
2.1.1塑件的材料 3
2.1.2聚苯乙烯的基本特性 3
2.1.3聚苯乙烯的成型特點(diǎn) 3
2.1.4聚苯乙烯的主要用途 3
2.1.5聚苯乙烯的注射成型工藝參數(shù) 4
2.2塑件的成型工藝 4
2.2.1注射成型的原理 4
2.2.2注射成型的工藝過(guò)程 4
2.2.3注射成型工藝參數(shù) 6
2.3注塑模的機(jī)構(gòu)組成 6
2.4方案論證 6
3 注射成型機(jī)的選擇 8
3.1估算塑件體積 8
3.2估算塑件質(zhì)量 8
3.3注塑機(jī)的注射容量 8
3.4鎖模 8
3.5選擇注塑機(jī)及注塑機(jī)的主要參數(shù) 9
3.5.1注射機(jī)的選擇 9
3.6注塑機(jī)的校核 9
3.6.1最大注射量校核 9
3.6.2 鎖模力校核 9
3.6.3 模具厚度校核 10
3.6.4開(kāi)模行程校核 10
4 澆注系統(tǒng)設(shè)計(jì) 11
4.1澆注系統(tǒng)的功能 11
4.1.1澆注系統(tǒng)的組成 11
4.1.2澆注系統(tǒng)設(shè)計(jì)原則 11
4.1.3澆注系統(tǒng)布置 12
4.2流道系統(tǒng)設(shè)計(jì) 13
4.2.1主流道設(shè)計(jì) 13
4.2.2冷料井設(shè)計(jì) 14
4.2.3分流道設(shè)計(jì) 14
4.2.4澆口設(shè)計(jì) 15
5 成型零件工作尺寸的計(jì)算 17
5.1影響塑件尺寸精度的因素 17
5.2模具成型零件的工作尺寸計(jì)算 17
5.2.1成形收縮率 17
5.2.2模具成形零件的制造誤差 18
5.2.3零件的磨損 18
5.2.4模具的配合間隙的誤差 18
5.3型腔和型芯尺寸計(jì)算 18
5.3.1型腔徑向尺寸計(jì)算 18
5.3.2型腔的深度尺寸 18
5.3.3型芯的徑向尺寸 18
5.3.4型芯的高度尺寸 19
5.3.5中心距尺寸計(jì)算 19
5.4動(dòng)模板的強(qiáng)度校核 19
6 導(dǎo)向機(jī)構(gòu)的設(shè)計(jì) 22
6.1導(dǎo)向機(jī)構(gòu)的作用 22
6.2導(dǎo)柱導(dǎo)向機(jī)構(gòu) 22
6.2.1導(dǎo)向機(jī)構(gòu)的總體設(shè)計(jì) 22
6.2.2導(dǎo)柱的設(shè)計(jì) 22
6.2.3導(dǎo)套的設(shè)計(jì) 23
6.3推板導(dǎo)套導(dǎo)柱的結(jié)構(gòu)設(shè)計(jì) 23
7 脫模機(jī)構(gòu)的設(shè)計(jì) 25
7.1基本考慮和要求 25
7.2推出機(jī)構(gòu)的確定 25
7.3推件板脫模機(jī)構(gòu)設(shè)計(jì)的特點(diǎn)和基本原則 25
7.4頂桿橫截面直徑校核 26
7.4.1脫模力的計(jì)算 26
7.4.2推桿直徑的校核 26
8 側(cè)向分型與抽芯機(jī)構(gòu)的設(shè)計(jì) 28
8.1基本考慮和要求 28
8.1.1側(cè)向分型與抽芯機(jī)構(gòu)應(yīng)具備的基本功能 28
8.2抽芯機(jī)構(gòu)的概述 28
8.3斜導(dǎo)柱抽芯機(jī)構(gòu)設(shè)計(jì)原則與確定 28
8.4斜導(dǎo)柱抽芯機(jī)構(gòu)的有關(guān)參數(shù)計(jì)算 29
8.4.1抽芯距 29
8.4.2斜導(dǎo)柱傾斜角的確定 29
8.4.3斜導(dǎo)柱直徑的確定 30
8.4.4斜導(dǎo)柱長(zhǎng)度的計(jì)算 31
8.5滑塊的設(shè)計(jì) 32
8.6導(dǎo)滑槽的設(shè)計(jì) 32
8.7滑塊定位裝置 32
8.7.1滑塊的作用和結(jié)構(gòu)形式 32
8.8鎖緊塊 32
8.8.1鎖緊塊的作用 32
8.8.2鎖緊塊的設(shè)計(jì)要點(diǎn) 33
8.8.3鎖緊塊的結(jié)構(gòu)形式 33
9 模具的材料 34
9.1塑料模具用鋼的必要條件 34
9.2選擇鋼材的條件 34
9.3本模具材料的選擇 34
9.4模具的淬火硬度 35
9.5模具的表面粗糙度 35
9.6熱處理的選擇 35
10 模具的可行性分析 36
10.1其它結(jié)構(gòu)零部件設(shè)計(jì) 36
10.2本模具的特點(diǎn) 36
10.3市場(chǎng)前景與經(jīng)濟(jì)效益分析 36
11 結(jié)論 37
參考文獻(xiàn) 38
致 謝 39
畢業(yè)設(shè)計(jì)（論文）知識(shí)產(chǎn)權(quán)聲明 40
畢業(yè)設(shè)計(jì)（論文）獨(dú)創(chuàng)性聲明 41
4
1 緒論
1.1塑料成型與注塑模具
塑料工業(yè)是由塑料原料和塑料制品生產(chǎn)兩大系統(tǒng)組成，二者相輔相成，缺一不可，而塑料制品生產(chǎn)是實(shí)現(xiàn)塑料原料自身價(jià)值的唯一手段。塑料制品生產(chǎn)主要由成型、機(jī)械加工、表面裝飾、裝配等環(huán)節(jié)組成，其重要一環(huán)就是塑料成型。
塑料成型就是將各種形態(tài)的塑料原料（粉料、粒料、溶液或分散體）制成所需形狀的制品或胚件的過(guò)程。塑料成型的方法很多，如注塑、吹塑、擠出等等。而注塑成型以其能成型高尺寸精度、高復(fù)雜性的制品和高效率占有重要一席。
塑料注塑成型過(guò)程是，塑料原料從注塑機(jī)的料斗進(jìn)入加熱筒，經(jīng)塑化后由柱塞或螺桿的推動(dòng)，在一定壓力下通過(guò)噴嘴進(jìn)入模具型腔，經(jīng)冷卻固化后而開(kāi)模獲得制品（塑件）。除少數(shù)幾種塑件外，幾乎所有的塑件都可以注塑成型。
塑模設(shè)計(jì)的傳統(tǒng)方法，是依靠設(shè)計(jì)人員的經(jīng)驗(yàn)﹑技巧和現(xiàn)有的設(shè)計(jì)數(shù)據(jù)，從對(duì)塑件的工藝計(jì)算到塑模的設(shè)計(jì)制圖，全靠手工勞動(dòng)。對(duì)塑模的制造就更需要專(zhuān)業(yè)人員付出大量的繁雜勞動(dòng)。所以塑件的質(zhì)量和數(shù)量都遠(yuǎn)不能滿足生產(chǎn)發(fā)展的需要。隨著計(jì)算器技朮的廣泛應(yīng)用，塑模設(shè)計(jì)和制造采用了CAD/CAM系統(tǒng)，從而大大提高了模具設(shè)計(jì)制造的效率。
Journal of Materials Processing Technology 176 (2006) 273277A technical note on the characterization of electroformednickel shells for their application to injection moldsMario D. Monzon, M. Dolores Marrero, A. Nizardo Benitez,Pedro M. Hernandez, J. Francisco CardenesUniversidad de Las Palmas de Gran Canaria, Departamento de Ingenieria Mecanica, SpainReceived 19 November 2003; received in revised form 14 January 2006; accepted 11 April 2006AbstractThe techniques of rapid prototyping and rapid tooling have been widely developed during the last years. In this article, electroforming as aprocedure to make cores for plastics injection molds is analysed. Shells are obtained from models manufactured through rapid prototyping usingthe FDM system. The main objective is to analyze the mechanical features of electroformed nickel shells, studying different aspects related to theirmetallographic structure, hardness, internal stresses and possible failures, by relating these features to the parameters of production of the shellswith an electroforming equipment. Finally a core was tested in an injection mold. 2006 Elsevier B.V. All rights reserved.Keywords: Electroplating; Electroforming; Microstructure; Nickel1. IntroductionOne of the most important challenges with which modernindustry comes across is to offer the consumer better productswith outstanding variety and time variability (new designs). Forthis reason, modern industry must be more and more compet-itive and it has to produce with acceptable costs. There is nodoubt that combining the time variable and the quality vari-able is not easy because they frequently condition one another;the technological advances in the productive systems are goingto permit that combination to be more efficient and feasiblein a way that, for example, if it is observed the evolution ofthe systems and techniques of plastics injection, we arrive atthe conclusion that, in fact, it takes less and less time to puta new product on the market and with higher levels of qual-ity. The manufacturing technology of rapid tooling is, in thisfield, one of those technological advances that makes possiblethe improvements in the processes of designing and manufac-turing injected parts. Rapid tooling techniques are basicallycomposed of a collection of procedures that are going to allowus to obtain a mold of plastic parts, in small or medium series,in a short period of time and with acceptable accuracy levels.Their application is not only included in the field of makingE-mail address: mmonzondim.ulpgc.es (M.D. Monzon).plastic injected pieces 13, however, it is true that it is wherethey have developed more and where they find the highestoutput.This paper is included within a wider research line where itattempts to study, define, analyze, test and propose, at an indus-trial level, the possibility of creating cores for injection moldsstarting from obtaining electroformed nickel shells, taking asan initial model a prototype made in a FDM rapid prototypingequipment.It also would have to say beforehand that the electro-forming technique is not something new because its appli-cations in the industry are countless 3, but this researchwork has tried to investigate to what extent and under whichparameters the use of this technique in the production ofrapid molds is technically feasible. All made in an accu-rate and systematized way of use and proposing a workingmethod.2. Manufacturing process of an injection moldThe core is formed by a thin nickel shell that is obtainedthrough the electroforming process, and that is filled with anepoxic resin with metallic charge during the integration in thecore plate 4 This mold (Fig. 1) permits the direct manufactur-ing by injection of a type a multiple use specimen, as they are0924-0136/$ see front matter 2006 Elsevier B.V. All rights reserved.doi:10.1016/j.jmatprotec.2006.04.003274M.D. Monzon et al. / Journal of Materials Processing Technology 176 (2006) 273277Fig. 1. Manufactured injection mold with electroformed core.defined by the UNE-EN ISO 3167 standard. The purpose of thisspecimen is to determine the mechanical properties of a collec-tion of materials representative industry, injected in these toolsanditscoMParisonwiththepropertiesobtainedbyconventionaltools.Thestagestoobtainacore4,accordingtothemethodologyresearched in this work, are the following:(a) Design in CAD system of the desired object.(b) Model manufacturing in a rapid prototyping equipment(FDM system). The material used will be an ABS plastic.(c) Manufacturing of a nickel electroformed shell starting fromthe previous model that has been coated with a conductivepaint beforehand (it must have electrical conductivity).(d) Removal of the shell from the model.(e) Production of the core by filling the back of the shell withepoxy resin resistant to high temperatures and with therefrigerating ducts made with copper tubes.Theinjectionmoldhadtwocavities,oneofthemwastheelectro-formed core and the other was directly machined in the movingplaten.Thus,itwasobtained,withthesametoolandinthesameprocess conditions, to inject simultaneously two specimens incavities manufactured with different technologies.3. Obtaining an electroformed shell: the equipmentElectrodeposition 5,6 is an electrochemical process inwhich a chemical change has its origin within an electrolytewhen passing an electric current through it. The electrolyticbath is formed by metal salts with two submerged electrodes,an anode (nickel) and a cathode (model), through which it ismade to pass an intensity coming from a DC current. Whenthe current flows through the circuit, the metal ions present inthe solution are transformed into atoms that are settled on thecathode creating a more or less uniform deposit layer.The plating bath used in this work is formed by nickelsulfamate 7,8 at a concentration of 400ml/l, nickel chloride(10g/l), boric acid (50g/l), Allbrite SLA (30cc/l) and Allbrite703 (2cc/l). The selection of this composition is mainly dueto the type of application we intend, that is to say, injectionmolds, even when the injection is made with fibreglass. Nickelsulfamate allows us to obtain an acceptable level of internalstresses in the shell (the tests gave results, for different processconditions, not superior to 50MPa and for optimum conditionsaround 2MPa). Nevertheless, such level of internal pressure isalso a consequence of using as an additive Allbrite SLA, whichis a stress reducer constituted by derivatives of toluenesulfon-amide and by formaldehyde in aqueous solution. Such additivealso favours the increase of the resistance of the shell whenpermitting a smaller grain. Allbrite 703 is an aqueous solutionof biodegradable surface-acting agents that has been utilizedto reduce the risk of pitting. Nickel chloride, in spite of beingharmfulfortheinternalstresses,isaddedtoenhancetheconduc-tivity of the solution and to favour the uniformity in the metallicdistribution in the cathode. The boric acid acts as a pH buffer.The equipment used to manufacture the nickel shells testedhas been as follows: Polypropylene tank: 600mm400mm500mm in size. Three teflon resistors, each one with 800W. Mechanical stirring system of the cathode. System for recirculation and filtration of the bath formed bya pump and a polypropylene filter. Chargingrectifier.Maximumintensityincontinuous50Aandcontinuous current voltage between 0 and 16V. Titanium basket with nickel anodes (Inco S-Rounds Elec-trolytic Nickel) with a purity of 99%. Gases aspiration system.Oncethebathhasbeendefined,theoperativeparametersthathave been altered for testing different conditions of the processhave been the current density (between 1 and 22A/dm2), thetemperature (between 35 and 55C) and the pH, partially mod-ifying the bath composition.4. Obtained hardnessOne of the most interesting conclusions obtained during thetests has been that the level of hardness of the different electro-formed shells has remained at rather high and stable values. InFig. 2, it can be observed the way in which for current densityvalues between 2.5 and 22A/dm2, the hardness values rangefrom 540 and 580HV, at pH 40.2 and with a temperatureof 45C. If the pH of the bath is reduced at 3.5 and the tem-perature is 55C those values are above 520HV and below560HV. This feature makes the tested bath different from otherconventional ones composed by nickel sulfamate, allowing tooperate with a wider range of values; nevertheless, such opera-Fig. 2. Hardness variation with current density. pH 40.2, T=45C.M.D. Monzon et al. / Journal of Materials Processing Technology 176 (2006) 273277275tivitywillbelimiteddependingonotherfactors,suchasinternalstress because its variability may condition the work at cer-tain values of pH, current density or temperature. On the otherhand, the hardness of a conventional sulfamate bath is between200250HV, much lower than the one obtained in the tests. Itis necessary to take into account that, for an injection mold,the hardness is acceptable starting from 300HV. Among themost usual materials for injection molds it is possible to findsteel for improvement (290HV), steel for integral hardening(520595HV), casehardened steel (760800HV), etc., in sucha way that it can be observed that the hardness levels of thenickel shells would be within the mediumhigh range of thematerials for injection molds. The objection to the low ductilityof the shell is compensated in such a way with the epoxy resinfilling that would follow it because this is the one responsiblefor holding inwardly the pressure charges of the processes ofplastics injection; this is the reason why it is necessary for theshell to have a thickness as homogeneous as possible (above aminimum value) and with absence of important failures such aspitting.5. Metallographic structureInordertoanalyzethemetallographicstructure,thevaluesofcurrentdensityandtemperatureweremainlymodified.Thesam-ples were analyzed in frontal section and in transversal section(perpendicular to the deposition). For achieving a convenientpreparation, they were conveniently encapsulated in resin, pol-ished and etched in different stages with a mixture of aceticacid and nitric acid. The etches are carried out at intervals of15, 25, 40 and 50s, after being polished again, in order to beobserved afterwards in a metallographic microscope OlympusPME3-ADL 3.3/10.Before going on to comment the photographs shown in thisarticle,itisnecessarytosaythatthemodelsusedtomanufacturetheshellsweremadeinaFDMrapidprototypingmachinewherethe molten plastic material (ABS), that later solidifies, is settledlayer by layer. In each layer, the extruder die leaves a threadapproximately 0.15mm in diameter which is compacted hori-zontal and vertically with the thread settled inmediately after.Thus, in the surface it can be observed thin lines that indicatethe roads followed by the head of the machine. These lines aregoingtoactasareferencetoindicatethereproducibilitylevelofthe nickel settled. The reproducibility of the model is going tobe a fundamental element to evaluate a basic aspect of injectionmolds: the surface texture.The tested series are indicated in Table 1.Table 1Tested seriesSeriespHTemperature (C)Current density (A/dm2)14.2 0.2552.2223.9 0.2455.5634.0 0.24510.0044.0 0.24522.22Fig. 3. Series 1 (150), etch 1.Fig. 4. Series 2 (300), etch 2.Fig. 3 illustrates the surface of a sample of the series after thefirst etch. It shows the roads originated by the FDM machine,that is to say that there is a good reproducibility. It cannot bestill noticed the rounded grain structure. In Fig. 4, series 2, aftera second etch, it can be observed a line of the road in a wayless clear than in the previous case. In Fig. 5, series 3 and 2etch it begins to appear the rounded grain structure although itis very difficult to check the roads at this time. Besides, the mostdarkened areas indicate the presence of pitting by inadequateconditions of process and bath composition.Fig. 5. Series 3 (300), etch 2.276M.D. Monzon et al. / Journal of Materials Processing Technology 176 (2006) 273277Fig. 6. Plane transversal of series 2 (600), etch 2.Thisbehaviorindicatesthat,workingatalowcurrentdensityand a high temperature, shells with a good reproducibility of themodel and with a small grain size are obtained, that is, adequatefor the required application.If the analysis is carried out in a plane transversal to thedeposition, it can be tested in all the samples and for all the con-ditionsthatthegrowthstructureofthedepositislaminar(Fig.6),what is very satisfactory to obtain a high mechanical resistancealthough at the expense of a low ductibility. This quality is due,above all, to the presence of the additives used because a nickelsulfamate bath without additives normally creates a fibrous andnon-laminar structure 9. The modification until a nearly nullvalue of the wetting agent gave as a result that the laminar struc-ture was maintained in any case, that matter demonstrated thatthedeterminantforsuchstructurewasthestressreducer(AllbriteSLA).Ontheotherhand,itwasalsotestedthatthelaminarstruc-ture varies according to the thickness of the layer in terms of thecurrent density.6. Internal stressesOne of the main characteristic that a shell should have for itsapplicationlikeaninsertistohavealowlevelofinternalstresses.Different tests at different bath temperatures and current densi-ties were done and a measure system rested on cathode flexuraltensiometer method was used. A steel testing control was usedwith a side fixed and the other free (160mm length, 12.7mmwidthandthickness0.3mm).Becausethemetallicdepositionisonly in one side the testing control has a mechanical strain (ten-sile or compressive stress) that allows to calculate the internalstresses. Stoney model 10 was applied and was supposed thatnickelsubstratumthicknessisenoughsmall(3?m)toinfluence,in an elastic point of view, to the strained steel part. In all thetested cases the most value of internal stress was under 50MPafor extreme conditions and 2MPa for optimal conditions, anacceptable value for the required application. The conclusionis that the electrolitic bath allows to work at different condi-tions and parameters without a significant variation of internalstresses.Fig. 7. Analysis by photoelasticity of injected specimens.7. Test of the injection moldTests have been carried out with various representative ther-moplastic materials such as PP, PA, HDPE and PC, and ithas been analysed the properties of the injected parts such asdimensions, weight, resistance, rigidity and ductility. Mechani-calpropertiesweretestedbytensiledestructivetestsandanalysisbyphotoelasticity.About500injectionswerecarriedoutonthiscore, remaining under conditions of withstanding many more.In general terms, important differences were not noticedbetween the behavior of the specimens obtained in the core andthe ones from the machined cavity, for the set of the analysedmaterials. However in the analysis by photoelasticiy (Fig. 7)it was noticed a different tensional state between both typesof specimens, basically due to differences in the heat transfer-enceandrigidityoftherespectivemoldcavities.Thisdifferenceexplainstheductilityvariationsmoreoutstandinginthepartiallycrystalline materials such as HDPE and PA 6.For the case of HDPE in all the analysed tested tubes it wasnoticed a lower ductility in the specimens obtained in the nickelcore, quantified about 30%. In the case of PA 6 this value wasaround 50%.8. ConclusionsAfter consecutive tests and in different conditions it has beencheckedthatthenickelsulfamatebath,withtheutilizedadditiveshas allowed to obtain nickel shells with some mechanical prop-erties acceptable for the required application, injection molds,that is to say, good reproducibility, high level of hardness andgood mechanical resistance in terms of the resultant laminarstructure. The mechanical deficiencies of the nickel shell willbe partially replaced by the epoxy resin that finishes shaping thecore for the injection mold, allowing to inject medium series ofplastic parts with acceptable quality levels.References1 A.E.W. Rennie, C.E. Bocking, G.R. Bennet, Electroforming of rapid pro-totyping mandrels for electro discharge machining electrodes, J. Mater.Process. Technol. 110 (2001) 186196.2 P.K.D.V. Yarlagadda, I.P. Ilyas, P. Chrstodoulou, Development of rapidtooling for sheet metal drawing using nickel electroforming and stereolithography processes, J. Mater. Process. Technol. 111 (2001) 286294.M.D. Monzon et al. / Journal of Materials Processing Technology 176 (2006) 2732772773 J. Hart, A. Watson, Electroforming: A largely unrecognised but expand-ing vital industry, Interfinish 96, 14 World Congress, Birmingham, UK,1996.4 M. Monz on, et al., Aplicaci on del electroconformado en la fabricaci onr apida de moldes de inyecci on, Revista de Pl asticos Modernos. 84 (2002)557.5 L.F. Hamilton, et al., C alculos de Qu mica Anal tica, McGraw Hill,1989.6 E. Julve, Electrodeposici on de metales, 2000 (E.J.S.).7 A. Watson, Nickel Sulphamate Solutions, Nickel Development Institute,1989.8 A. Watson, Additions to Sulphamate Nickel Solutions, Nickel Develop-ment Institute, 1989.9 J. Dini, Electrodeposition Materials Science of Coating and Substrates,Noyes Publications, 1993.10 J.W. Judy, Magnetic microactuators with polysilicon flexures, MastersReport, Department of EECS, University of California, Berkeley, 1994.www.bsac.eecs.berkeley.edu/arhive/masters/jjudy/chapter3.pdf (cap?. 3).
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