洗面奶瓶盖注射模设计【护手霜瓶盖】【一模两腔】【说明书+CAD】
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湖南大学衡阳分校毕 业 设 计课 题 洗面奶瓶盖注射模专 业 模具设计与制造班 级 2003级模具二班 学生姓名 指导老师 2006年05月25日湖南大学衡阳分校毕业设计计 算 内 容说 明目 录一拟定模具的结构型式二 浇注系统的设计三 成型零件的设计四 模架的确定五 排气槽的设计六 脱模推出机构的设计七 定距拉板机构设计 八 温度调节系统的设计九 导向定位系统的设计十 心得体会十一参考文献 共 15 页 第 1 页湖南大学衡阳分校毕业设计计 算 内 容说 明塑料壳体设计一、拟定模具的结构型式1. 塑件成型工艺性分析该塑件是一塑料壳体,如图1所示, 塑件壁件属薄壁塑件,生产批量很大。材料为PC(聚碳酸脂):突出的冲击强度,较高的弹性模量和尺寸稳定性。无色透明,着色性和电绝缘性优良,透光性好,耐寒性好,使用性能好。但粘性大,流动性较差,耐磨性差。力学性能一般,易产生应力碎裂,适用于制造绝缘透件,透明件等。本塑件为透明件。 图1 2. 分型面位置的确定 根据塑件结构型式,为便于塑件脱模和自动落料,塑件留在动模,并考虑和保证塑件的外观不遭到损坏,应选择三板双分型面。1、在定模座板与定模板之间2、在壳体的底平面。 3. 确定型腔数量和排列方式1)型腔数目的确定该塑件精度要求不高,又是大批大量生产,采用一模两腔的形式。考虑到模具制造费用低一点,设备运转费用小一点,初定为一模两腔的模具型式。2)型腔排列形式的确定 为了确保塑件质量的均一和稳定,尽量使型腔排列紧凑,便于减小模具的外型尺寸,本设计的型腔的排列方 式采用单列直排。图2所示。为了保证塑件的外型尺寸和精度,此本设计采用脱模板 推出脱模的方法。 共 15 页 第 2 页湖南大学衡阳分校毕业设计计 算 内 容说 明4. 模具结构型式的确定从上面分析中可知,本模具拟采用一模两腔,单列直排,推板推出,流道采用平衡式,浇口采用点 浇口,定模需要设置分型面以便自动落料,动模部分需要一块脱模板,因此基本上可确定模具结构型式为双分型面注射模。 图 2 5. 注射机型号的选定1)注射量的计算通过计算或Pro/E建模分析,塑件质量m1为109g,塑件体积流道凝料的质量m2还是个未知数,可按塑件质量的0.4倍来估算。从上述分析中确定为一模二腔,所以注射量为:m=1.4nm1=1.52109=348.8g2)塑件和流道凝料在分型面上的投影面积及所需锁模力的计算流道凝料(包括浇口)在分型面上的投影面积A2,在模具设计前是个未值,根据多型腔模的统计分析,大致是每个塑件在分型面上的投影面积A1的0.20.5倍,因此可用0.4nA1来进行估算,所以A=nA1+A2=nA1+0.4nA1=1.4nA1=式中Fm=A =3.3640=1344KN式中为型腔压力,取40MPa(查表得到)。3)选择注射机根据每一生产周期的注射量和锁模力的计算值,可选用SZ500/200卧式注射机(上海塑料机械厂),技术参数如表1所列:表1 注射机主要技术参数理论注射容量/500锁模力 /KN2000螺杆直径mm55拉杆内间距/mm570570注射压力MPa150移模行程/mm500注射速率(g/s)173最大模厚/mm500塑化能力(g/s)110最小模厚/mm280螺杆转速(r/min)0180定位孔直径/mm160喷嘴球半径SR20喷嘴孔直径/mm4锁模方式双曲轴 共 15 页 第 3 页湖南大学衡阳分校毕业设计计 算 内 容说 明4)注射机有关参数的校核(1) 由注射机料筒塑化速率校核模具的型腔数nk注射机最大注射量的利用系数,一般取0.8;M注射机的额定塑化量(110g/s);t成型周期,取40s。其他安装尺寸的校核要待模架选定,结构尺寸确定以后才可进行。二、浇注系统的设计1. 主流道设计1)主流道尺寸:根据所选注塑机参数可得主流道小端尺寸为:d=注射机喷嘴尺寸+(0.51)=4+1=5mm主流道球面半径:SR=喷嘴球面半径(12)=20+2=22mm2)主流道衬套形式本设计虽然是小型模具,但为了便于加工和缩 短主流道长度,衬套和定位圈还是设计成分体式,主流道长度取32等于定模板的厚度(见模架的确 图3定和装配图)。衬套如图3所示, 材料采用T10A钢,热处理淬火后表面硬度为5357HRC。3)主流道凝料体积为: 2. 分流道设计1) 分流道布置形式为了满足良好的压力传递和保持理想的填充状态,使塑料熔体尽快地经分流道均衡的分配到各个型腔,因此,采用平衡式分流道。 共 15页 第 4 页湖南大学衡阳分校毕业设计计 算 内 容说 明2) 分流道长度L1=77.5mm, L2=8mm; 图4为分流道的布置。3) 分流道的形状、截面尺寸以及凝料体积 (1) 形状及截面尺寸 为了便于机械加工及凝料脱模,本设计 的分流道设置在分型面上定模一侧,截面形状采用加工工艺性比较好的梯形截面。梯形截面对塑料熔体的流动阻力不大,但由于材料的流动性能差,壁厚为4,所以 一般不采用下面的经验公式来确定截面尺寸: 而根据资料PC可取推荐最大值13所以取 D=10d=8 一级分流道L截面形状图5所示。二级分流道的尺寸为:D=8 H=8 d=4(2) 凝料体积分流道长度:L1=77.52=155mm, L2=82=16mm; 图5分流道截面积:A1= A2= 凝料体积: 5) 分流道的表面粗糙度分流道的表面粗糙度并不要求很低,一般取0.8m1.6m可,在此取1.6m,如图5所示。注射机型号参见塑料成型工艺与模具设计表4-1P100 共 15 页 第 5 页湖南大学衡阳分校毕业设计计 算 内 容说 明3 流道校核1)主流道剪切速率校核由经验公式式中主流道剪切速率偏大,主要是注射量大,喷嘴尺寸偏大,使主流道尺寸偏大所致。 2) 分流道剪切速率校核 图5 采用经验公式S在5之间,剪切速率校核合理。式中 t注射时间取1s C梯形周长(C=3.6cm)。4. 浇口的设计由于塑件是高度较大的平板件,故采用点浇口。由于材料的流动性能差,所以要采用宽浇口。塑料熔体以较低的流速、呈平行状态、平稳均匀地流人型腔,可降低塑件的内应力,减小翘曲变形,排气良好。浇口对称分布,塑件取出后要用另外去除,有微小痕迹。1)点口尺寸的确定 综上述,由经验数据得: 浇口截面形状如图6所示,试模时根据填充情况再进行调整。 共 15 页 第 6 页湖南大学衡阳分校毕业设计计 算 内 容说 明2) 浇口剪切速率的校核之间,剪切速率合适。4. 冷料穴的设计1) 主流道冷料穴如图7所示,采用半球形形式,并采用球形头拉料杆,该拉料杆固定在动模固定板上,开模时利用凝料对球头的包紧力,使主流道凝料从主流道衬套中脱出。2) 分流道冷料穴 图7 冷料穴 在分流道端部加长10mm(约1.5倍dn)作分流道冷料穴。三、成型零件的设计模具中确定塑件几何形状和尺寸精度的零件称为成型零件。在本设计中成型零件就是成形壳体外表面的凹模,成型内表面的凸模,由于塑件材料为透明材料故各成型表面均为镜面。1. 成型零件的结构设计1) 凹模(型腔)壳体型腔不是很深,故凹模可制成 整体式,先用洗削加工方法进行粗加工,然后进行电火花精加工,而镜面由人工抛光。虽整体模板都要用价格较贵重的模具钢,但只是小型模具,还是可以承受的。 图8 因此,凹模采用整体式。如图8所示,尺寸由所选模架决定。而型腔厚度取60mm. 2) 凸模(型芯)型芯是一个嵌入式型芯,由于各成型表面均为镜面,磨损不是很大,但由于采用脱模板脱模,磨损量增大。以及失误操作的话,影响模具寿命,必须及时更换,故可设计成嵌入式。如图9所示。 2. 成型零件钢材的选用壳体是大批量生产、成型零件所选用钢材耐磨性和 抗疲劳性能应该良好。机械加工性能和抛光性能也应良好。因此构成型腔凹模钢材选用NAK80。(订制其他材料的材质可和模架厂协商)。型芯因为是采用推板脱模,与型芯磨损较大,采用硬 图9 度较高的模具钢STD,淬火后表面硬度为5862HRC。3. 成型零件工作尺寸的计算(其图形见图纸12号)塑件尺寸公差按SJ137278标准中的6级精度选取。1) 型腔径向尺寸 共 15 页 第 7 页湖南大学衡阳分校毕业设计计 算 内 容说 明 式中 s 塑件平均收缩率;塑件外径尺寸;修正系数(取0.75);塑件公差值(查塑件公差表);制造公差取。 2) 型芯径向尺寸式中 s 塑件平均收缩率; 塑件外径尺寸;修正系数(取0.75);塑件公差值(查塑件公差表);制造公差取。 共 15 页 第 8 页湖南大学衡阳分校毕业设计计 算 内 容说 明 3) 型腔深度尺寸式中 H s塑件高度最大尺寸; 修正系数取0.6; 塑件公差值(查塑件公差表)。 4) 型芯高度尺寸式中 塑件孔深最小尺寸;修正系数取0.6; 塑件公差值(查塑件公差表)。 5)型芯或型孔之间的距离 4. 成型零件强度及支承板厚度计算1) 型腔侧壁厚度:其具体尺寸由模架尺寸确定; 底板厚度:取=25mm;计算参考塑料成型工艺与模具设计第五章第三节 P153 共 15 页 第 9 页 湖南大学衡阳分校毕业设计计 算 内 容说 明 式中 型腔压力,取40MPa; 材料弹性模量,取2.1105MPa; 根据注射塑料品种,模具刚度计算许用变形量。查表4-13得: 系数 查表4-15得: 查表 4-16得:两型腔之间受力是大小相等、方向相反、在合模状态下不会产生变形,因此两型腔之间壁厚只要满足结构设计的条件就可以了。所以完全满足强度和刚度的要求。压力,就可计算得到支承板的厚度。式中 支承板刚度计算许用变形量; 、W两垫块之间的距离(约为215);支承板长度,取315;型芯投影到支承板上的面积。型芯的面积此支承板厚度计算尺寸为50,对于小型模具还可减小一点,可利用两根推板导柱来对支承板进行支撑,这样支撑板厚度可近似为 共 15 页 第 10 页湖南大学衡阳分校毕业设计计 算 内 容说 明因此支承板厚度可取得稍薄一点,取标准厚度32。四、模架的确定根据型腔的布局可看出,型腔板尺寸为315400,又根据型腔侧壁最小厚度为17.13mm,再考虑到导柱、导套及联接螺钉布置应占的位置和采用推件板推出等各方面问题,确定选用模架序号为P4号(315L=315400),模架结构为P4的型式,如图10所示。 图10各模板尺寸的确定:1. A板尺寸 A板是定模型腔板,塑件高度45,在模板上还要开设一级和二级分流道,分流道有一定的厚度和长度,因此A板厚度取63mm。2. B板尺寸B板是凸模(型芯固定)板,取40mm(包括型芯总高45mm)。3. C垫块尺寸垫块=推出行程+推杆板厚度+推杆固定板厚度+(510)=45+25+20+(510)=95100根据计算,垫块厚度C取100。根据上述尺寸,确定模架序号为5号,板面为315400,模架结型 共 15 页 第 11 页湖南大学衡阳分校毕业设计计 算 内 容说 明 式为P4的标准模架。从选定模架可知,模架外形尺寸: 宽长高315400311()合格。模具平面尺寸400400570570(拉杆间距),合格;模具开模所需行程45(型芯高度)45(塑件高度)(510)95100500(注射机开模行程),合格;其他各参数在前面校核均合格,所以本模具所选注射机满足使用要求。五、排气槽的设计壳体成型型腔体积约为90.44cm3,由表1可计算得注射时 图11间约为2s,采用的是点浇口由型腔顶部注射,熔体先充满型腔顶部,然后再充满周边下部,这样型腔顶部不会造成憋气现象,气体会沿着分型面和型芯与推件板之间的轴向间隙向外排出,又有分型面设在浇注最后位置,这样的小零件一般不会造成憋气现象,故排气装置没有必要设计。 六、脱模推出机构的设计采用推板推出过程中,为了减小推杆与型芯的 摩擦,采用图11所示结构,在型芯板与推杆之间可作为导柱 导套,可以起到定位导向的作用。 共 15 页 第 12 页湖南大学衡阳分校毕业设计计 算 内 容说 明 七、定距拉板机构设计 如右图,模具开模时,由于弹簧的作用, 中间板与定模座板首先分开,以便取出两板之间的浇注系统凝料。继续开模时,由于定距拉板与固定在中间板上的限位钉接触,使中间板停止运动,这样随着动模的继续移动迫使模具沿第二分型面分开,进而由推出机构将塑件推出。 S=L+(35)=45+5=50L定模板厚度 八、温度调节系统的设计冷却系统的计算比较麻烦,故在此只进行简单估测计算,在单位时间内熔体凝固时所放出的热量应等于冷却水所带走的热量,模具温度设为40。 1. 冷却水的体积流量式中 W单位时间(每分钟)内注入模具中的塑料质量(kg/min),按每分钟注射2次,即: W=Q1单位质量的塑件制品在凝固时所放出的热量,PS为2.1102kJ/kg;冷却水的密度(1000kg/m3); C1冷却水的比热容(4.187kJ/kg);1冷却水出口温度(取26.5);1冷却水入口温度(取25)。 共 15 页 第 13页湖南大学衡阳分校毕业设计计 算 内 容说 明2. 确定冷却管道直径d为使冷却水处于湍流状态,查资料取d=15mm,而且由资料查处PC的Vmin=0.87。3. 确定冷却水在管道内的流速v由式 大于最低流速0.87m/s,所选管道直径 合理。4求冷却管道的总传热面积AA=60W Q1/h=0.001677316=1677.35.求冷却水道的孔数n所以,不需要设计冷却水道。九、导向定位系统的设计 由于塑件、模具属于小型,且注塑时间短, 图12 可采用四导柱导套导向定位。但又由于塑件上有两个孔,要求精度相对较高,故采用四导柱定位!为了中间板在工作过程中的导向与支承,所以必须在定模一侧设置导柱。因此将原有模架的四根动模导柱该成,对角导柱,即,两根在定模,两根在动模。布置如下图导柱直径R=32, 导套直径D=42; 。 共 15 页 第 14 页湖南大学衡阳分校毕业设计计 算 内 容说 明设计心得体会 在设计过程中,我把塑料制品成型及模具设计和其他资料书仔仔细细地阅读了一遍,从中我学懂了许多以前不懂的地方,也学到了许多以前没有学过的方面。 在设计时,由于没有实际经验,以前学过的东西好象不知道该如何应用,在老师的指导下,我综合比较了资料中各种模具的设计和其中应该要怎么做、以及要注意那些细节,终于我顺利的将模具设计出来。而整个设计的过程,使我更清楚地知道该如何将自己学到的知识应用到实际当中去,并将其完善。 对于我们不能不说是一种很好的锻炼,相信这次的设计会对我以后产生很大的帮助, 通过这次设计我深深体会到了书本与实际的区别,看懂与动手的差异!以前总认为学校学到的知识到了实际中未必有用,通过这次的设计才知道基础对现实中的作用是非常巨大的。也让我对过去学到的知识有了全新的了解,并充分利用它来完善自己。 十一、参考文献 1)塑料制品成型及模具设计 叶久新 王群 主编 2)塑料模具设计 刘昌祺 主编 3)模具设计与加工速查手册 彭建生 主编 4)塑料模具技术手册 编委会 主编 5)塑料注射模具设计技巧与实例 王文广 等主编 付:外文翻译 电火花加工 电火花加工法对加工超韧性的导电材料(如新的太空合金)特别有价值。这些金属很难用常规方法加工,用常规的切削刀具不可能加工极其复杂的形状,电火花加工使之变得相对简单了。在金属切削工业中,这种加工方法正不断寻找新的应用领域。塑料工业已广泛使用这种方法,如在钢制模具上加工几乎是任何形状的模腔。 电火花加工法是一种受控制的金属切削技术,它使用电火花切除(侵蚀)工件上的多余金属,工件在切削后的形状与刀具(电极)相反。切削刀具用导电材料(通常是碳)制造。电极形状与所需型腔想匹配。工件与电极都浸在不导电的液体里,这种液体通常是轻润滑油。它应当是点的不良导体或绝缘体。 用伺服机构是电极和工件间的保持0.00050.001英寸(0.010.02mm)的间隙,以阻止他们相互接触。频率为20000Hz左右的低电压大电流的直流电加到电极上,这些电脉冲引起火花,跳过电极与工件的见的不导电的液体间隙。在火花冲击的局部区域,产生了大量的热量,金属融化了,从工件表面喷出融化金属的小粒子。不断循环着的不导电的液体,将侵蚀下来的金属粒子带走,同时也有助于驱散火花产生的热量。 在最近几年,电火花加工的主要进步是降低了它加工后的表面粗糙度。用低的金属切除率时,表面粗糙度可达24vin.(0.050.10vin)。用高的金属切除率如高达15in3/h(245.8cm3/h)时,表面粗糙度为1000vin.(25vm)。 需要的表面粗糙度的类型,决定了能使用的安培数,电容,频率和电压值。快速切除金属(粗切削)时,用大电流,低频率,高电容和最小的间隙电压。缓慢切除金属(精切削)和需获得高的表面光洁度时,用小电流,高频率,低电容和最高的间隙电压。 与常规机加工方法相比,电火花加工有许多优点。 1 . 不论硬度高低,只要是导电材料都能对其进行切削。对用常规方法极难切削的硬质合金和超韧性的太空合金,电火化加工特别有价值。 2 . 工件可在淬火状态下加工,因克服了由淬火引起的变形问题。 3 . 很容易将断在工件中的丝锥和钻头除。 Electrical discharge machiningElectrical discharge machining has proved especially valuable in the machining of super-tough, electrically conductive materials such as the new space-age alloys. These metals would have been difficult to machine by conventional methods, but EDM has made it relatively simple to machine intricate shapes that would be impossible to produce with conventional cutting tools. This machining process is continually finding further applications in the metal-cutting industry. It is being used extensively in the plastic industry to produce cavities of almost any shape in the steel molds. Electrical discharge machining is a controlled metal removal technique whereby an electric spark is used to cut (erode) the workpiece, which takes a shape opposite to that of the cutting tool or electrode. The cutting tool (electrode) is made from electrically conductive material, usually carbon. The electrode, made to the shape of the cavity required, and the workpiece are both submerged in a dielectric fluid, which is generally a light lubricating oil. This dielectric fluid should be a nonconductor (or poor conductor) of electricity. A servo mechanism maintains a gap of about 0.0005 to 0.001 in. (0.01 to 0.02 mm) between the electrode and the work, preventing them from coming into contact with each other. A direct current of low voltage and high amperage is delivered to the electrode at the rate of approximately 20 000 hertz (Hz). These electrical energy impulses become sparks which jump the dielectric fluid. Intense heat is created in the localized area of the park impact, the metal melts and a small particle of molten metal is expelled from the surface of the workpiece . The dielectric fluid, which is constantly being circulated, carries away the eroded particles of metal and also assists in dissipating the heat caused by the spark.In the last few years, major advances have been made with regard to the surface finishes that can be produced. With the low metal removal rates, surface finishes of 2 to 4 um. (0.05 to 0.10um) are possible. With high metal removal rates finishes of 1 000uin. (25um) are produced.The type of finish required determines the number of amperes which can be used, the capacitance, frequency, and the voltage setting. For fast metal removal (roughing cuts), high amperage, low frequency, high capacitance, and minimum gap voltage are required. For slow metal removal (finish cut) and good surface finish, low amperage, high frequency, low capacitance, and the highest gap voltage are required.Electrical discharge machining has many advantages over conventional machining processes.1. Any material that is electrically conductive can be cut, regardless of its hardness. It is especially valuable for cemented carbides and the new supertough space-age alloys that are extremely difficult to cut by conventional means.2. Work can be machined in a hardened state, thereby overcoming the deformation caused by the hardening process.3. Broken taps or drills can readily be removed from workpieces. 4. It does not create stresses in the work material since the tool (electrode) never comes in contact with the work.南京理工大学泰州科技学院毕业设计(论文)外文资料翻译系部: 机械工程系 专 业: 机械工程及自动化 姓 名: 王 锋 学 号: 05010230 外文出处: 中国机械资讯网 BBS.CMIW.CN 附 件: 1.外文资料翻译译文;2.外文原文。 指导教师评语:译文基本符合翻译原文,个别词汇不符合语境。语句较为通顺,条理比较清楚,专业用语翻译基本恰当,符合中文语法,整体翻译质量较好。 签名: 年 月 日附件1:外文资料翻译译文在注塑模应用方面,外形电铸镍的技术注释摘要 在过去几年,快速成型技术及快速模具在发达国家已广泛应用。在这篇文章中,作为一种范例,分析电芯塑料注射模具。通过快速成型,利用差分系统得到镍壳模型。主要目的是分析镍壳力学特征,学习不同方面的金相组织、硬度、内压,失败的可能性。以这些特色的有关参数生产镍壳电设备,终于得到了一个注塑模具核心部分。关键词:电镀; 电制;显微组织; 镍文章概要1. 引言2. 注塑模具制造过程3. 电铸壳获取:设备4. 获得硬度5. 金相组织6. 内压7. 测试的注塑模具8. 结论1引言现代工业遇到的最重要的挑战之一是在很短的时间内向消费者提供更好的产品。因此,现代工业必须有更强的竞争性和适应更合理的生产成本。 毫无疑问,结合时间和质量并不容易,因为他们经常互相变换。生产系统的科技进步,在方式将可更有效和可行的促进组合,例如,如果是演化的观测系统和注塑技术、我们得出的结论是事实上可以用很少的时间和高质量把新产品推向市场。在模具制造领域中,先进的快速模具制造技术有可能改善设计和制造过程注入部分。快速模具制造技术基本上是由程序集中组成,在短短的时间里,以可接受的精度水平使我们获取小型系列的塑料模具零件。其应用领域不仅包括制作塑胶件注,而且他们研制并创造了最高产量。本文包括在广泛试图研究确定分析测试和建议的科研第一线,在产业层次形成从注塑模具获取镍壳核心的可能性,同时用差分模型快速成型设备取得了初步的模型。也将不得不说,无数业内人士事前并没有应用任何新电铸技术,但很大程度上,在快速模具的生产技术上使用这种试图调查研究工作.,运用所有准确,制度化的方式方法并提出了工作。2注塑模具制造过程核心是透过电进程的镍壳。这是一个主管充满金属环氧树脂的一核心板块。模具(图1)制造时可以直接注射A型多用标本,确定SO3167标准的甲状旁腺恩目的是要确定这个试样的力学性能和通过常规手段收集工业材料。图1注塑模具制造与电核心根据这一方法研制工作,该阶段取得核心有以下几方面:(一) CAD系统预期目标的设计(二) 快速原型设备制造模型(频分多路复用)。该材料将被用于ABS塑料(三) 以以往的模式生产事前已经涂了导电涂料的镍电壳(必须有导电)(四) 从模型中清理壳牌(五) 生产背面填充着随着铜管与冷冻槽流动具有抗高温壳牌环氧树脂的核 心 注塑模具有两个空洞,他们一个是电加工的核心,另一个是直接在机械上移动压板。因此,它获得了与同一工具及同一工艺条件同时在空洞里注入两种不同的标本制造技术。3电铸壳获取:设备电镀是一个电化学过程中的化学变化, 当电流通过,它起源于电解质。该电解槽是由金属盐溶液淹没两个电极,一个阳极(镍)、阴极(示范)。通过来自一定强度的直流电。当电流流经电路,目前在溶液中金属离子转化为原子,堆积于阴极或多或少的创造沉淀层。这项工作采用的镀液是由镍、磺酸集中在400 毫升/公升,氯化镍(10微克/公升)、硼酸(50微克/公升),allbrite SLA (30立方厘米/公升),703allbrite(2立方厘米/公升)。这种合成物的选择主要取决于我们打算的应用类型即注塑模具,即使注射了玻璃纤维。磺酸镍让我们获得可以接受的壳内压 (测试结果,不同工艺条件,不高于50兆帕和2兆帕左右最佳条件)。 不过这种程度的内部压力也是使用添加剂Allbrite SLA强硝酸脂、甲醛水溶液产生的后果。这种添加剂当允许较小壳颗粒增加阻力。703allbrite是降解水溶液以减少表面腐蚀。氯化镍,尽管内压有害,增强导电溶液中的金属均匀分布在阴极。硼酸作为pH值的缓冲。一旦已确定浴,有效验的参数测试改变不同条件过程的电流密度(在1至22a/立方分米),温度(35至55)和pH值, 部分的改变镀液组成。4获得硬度在测试期间已获得一个非常有趣的结论,对不同程度硬度的镍壳一直保持在相当高的稳定价值。在图2,在pH40.2,摄氏45时,可以观察到电流密度值为2.5和22之间。硬度值的范围从高压540至580。如果pH值降为3.5,气温下降55,硬度值的范围从高压520以上至高压560以下。由磺酸镍组成的这一特点使得测试不同于其他传统业务,观念是允许经营范围更广;然而这种有限性的将取决于其他因素。例如内应力,因为其工作状态可能在某些变性的pH值、电流密度和温度下。在另一方面,传统的硬度介于200-250高压磺酸浴,远低于在测试中获得的。有必要要考虑到对于注塑模具,接受300高压硬度。其中最常见的材料就可以找到注塑模具钢(高压290),积分硬化钢(高压520-595),casehardened钢(高压760-800)等。这样可以观察到中高幅度硬度水平的镍壳注塑模具材料,有偿壳牌是反对用低延性的环氧树脂填充。因为注塑是一个内压控制进程, 这也是为什么必须要壳厚度尽可能均匀(以上最低值),避免重大失误。如图:图2硬度变化与电流密度4+0.2pH值455金相组织主要是为了改良而分析金相结构、电流密度、温度值。样品分析、横向部分(垂直于沉积)为实现准备便捷,树脂被方便的封装在含有硝酸,醋酸混合物的瓶子,进行每隔15,25,40,50秒收盘后擦拭。为了事后在奥林匹斯金相显微镜碲下观察PME3-ADL 3.3/10。在评论文中的照片之前,有必要讨论用差分快速成型机械制造逐层贯通的熔融塑料 (ABS) 壳模具。 每一层挤出模具留下的螺纹直径约0.15毫米即横向和纵向的中间媒介。因此,在机器的主要表面可以观察到薄线标明的道路。这些线路将作为参考解决水平镍重复性显示。重复性模式将是一个评估注塑模具基本内容的基本要素:表面纹理。该系列测试表1所示:表1检验系列系列pH温度()电流密度A/mm214.20.2552.2223.90.2455.5634.00.24510.0044.00.24522.22图3显示第一次蚀刻的系列表面样本。它显示了频分多路复用机的原理,也就是说有一个良好的重复性。 它仍无法察觉圆形的颗粒结构,在图4系列2之后的第二蚀刻可以观察到一条线道较前明显减少。在图5系列2和3,虽然这时路径很难查出,蚀刻已开始出现了一批颗粒结构。另外,最黑暗的地方显示含有合成物浴的蚀刻过程。图 3. 系列1(150)、蚀刻1图 4. 系列2(300), 蚀刻2图 5. 系列3(300),蚀刻2这一行为表明,工作在低电流密度、高温下,壳以良好的再现能力获得粒度即适当的应用。如果进行了平面沉积的横向分析,它可以在所有的样品和一切条件下测试,沉淀物的增长结构是由薄片组成的(图6)。虽然延展性低,但是取得了高机械阻力。这取决于质量,,首先存在添加剂。因为磺酸镍浴没有添加剂,通常制造纤维和非层结构5。更正直到近似于空值的润湿剂,在任何情况下保持层结构表明这种结构的应力消脂(allbrite习得)。在另一方面,据测试根据不同层结构层厚度的计算电流密度。图 6. 机横向系列2 (600),蚀刻2.6内压其中一个主要特征是壳的应用像输入低水平内压。用阴极张力法在不同电流密度和镀液温度测量系统下做不同的测试。钢铁被用来测试与控制自由和固定(160毫米长度 宽度12.7毫米,厚度0.3毫米)。因为沉积金属是唯一允许检测控制机械应变(拉伸或压应力)和计算内压。对于部分钢铁来说,从弹性的角度来看Stoney模型应用被假定镍底层厚度不够,表面影响小(3微米)。在所有测试情形中最佳条件是内部压力50和极端条件下为2兆帕,为所需的可接受值。最后的结论是在不同的条件和工作参数下电镀浴允许无明显变化内压。7测试的注塑模具试验已在各种代表性热塑性材料中进行如聚丙烯、镁、高密度聚乙烯和PC。分析零件的性能,如注射大小、重量、抗延性僵化。测试拉伸力学性能和分析光破坏性。这一核心进行约500注射量,其余条件下经受更多。一般而言,重大分歧都是未察觉样本核心之间的行为。从加工腔到一整套的材料,但是在分析光弹性时(图七)发现了两种不同张标本,基本上是取决于炎热划转、浇注腔的刚度。这种差异说明延性变化较突出的部分材料,如聚乙烯、六镁。图 7分析光注入标本在所有分析化验中发现高密度聚乙烯管案例是一个较低延性标本。所得镍核心,量化30%左右。在这种情况下六镁值也接近50%。8结论经过连续的测试和不同的条件下已经清查磺酸镍浴已获准使用添加剂。镍壳将获得一些可以接受的注塑模具的机械性能。也就是说,重复性好,高硬度及良好的机械阻力。因而机械层结构不足的部分将取代镍壳的环氧树脂饰面。核心为注塑塑造,允许注入可接受质量水平中型系列塑料零件。附件2:外文原文(复印件)A technical note on the characterization of electroformed nickel shells for their application to injection molds Abstract The techniques of rapid prototyping and rapid tooling have been widely developed during the last years. In this article, electroforming as a procedure to make cores for plastics injection molds is analysed. Shells are obtained from models manufactured through rapid prototyping using the FDM system. The main objective is to analyze the mechanical features of electroformed nickel shells, studying different aspects related to their metallographic structure, hardness, internal stresses and possible failures, by relating these features to the parameters of production of the shells with an electroforming equipment. Finally a core was tested in an injection mold. Keywords: Electroplating; Electroforming; Microstructure; Nickel Article Outline1. Introduction 2. Manufacturing process of an injection mold 3. Obtaining an electroformed shell: the equipment 4. Obtained hardness 5. Metallographic structure 6. Internal stresses 7. Test of the injection mold 8. Conclusions 1. IntroductionOne of the most important challenges with which modern industry comes across is to offer the consumer better products with outstanding variety and time variability (new designs). For this reason, modern industry must be more and more competitive and it has to produce with acceptable costs. There is no doubt that combining the time variable and the quality variable is not easy because they frequently condition one another; the technological advances in the productive systems are going to permit that combination to be more efficient and feasible in a way that, for example, if it is observed the evolution of the systems and techniques of plastics injection, we arrive at the conclusion that, in fact, it takes less and less time to put a new product on the market and with higher levels of quality. The manufacturing technology of rapid tooling is, in this field, one of those technological advances that makes possible the improvements in the processes of designing and manufacturing injected parts. Rapid tooling techniques are basically composed of a collection of procedures that are going to allow us 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 making plastic injected pieces , however, it is true that it is where they have developed more and where they find the highest output. This paper is included within a wider research line where it attempts to study, define, analyze, test and propose, at an industrial level, the possibility of creating cores for injection molds starting from obtaining electroformed nickel shells, taking as an initial model a prototype made in a FDM rapid prototyping equipment. It also would have to say beforehand that the electroforming technique is not something new because its applications in the industry are countless but this research work has tried to investigate to what extent and under which parameters the use of this technique in the production of rapid molds is technically feasible. All made in an accurate and systematized way of use and proposing a working method. 2. Manufacturing process of an injection moldThe core is formed by a thin nickel shell that is obtained through the electroforming process, and that is filled with an epoxic resin with metallic charge during the integration in the core plate 。 This mold (Fig. 1) permits the direct manufacturing by injection of a type a multiple use specimen, as they are defined by the UNE-EN ISO 3167 standard. The purpose of this specimen is to determine the mechanical properties of a collection of materials representative industry, injected in these tools and its coMParison with the properties obtained by conventional tools. Fig. 1.Manufactured injection mold with electroformed core.The stages to obtain a core, according to the methodology researched 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 from the previous model that has been coated with a conductive paint 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 with epoxy resin resistant to high temperatures and with the refrigerating ducts made with copper tubes.The injection mold had two cavities, one of them was the electroformed core and the other was directly machined in the moving platen. Thus, it was obtained, with the same tool and in the same process conditions, to inject simultaneously two specimens in cavities manufactured with different technologies. 3. Obtaining an electroformed shell: the equipmentElectrodeposition is an electrochemical process in which a chemical change has its origin within an electrolyte when passing an electric current through it. The electrolytic bath is formed by metal salts with two submerged electrodes, an anode (nickel) and a cathode (model), through which it is made to pass an intensity coming from a DC current. When the current flows through the circuit, the metal ions present in the solution are transformed into atoms that are settled on the cathode creating a more or less uniform deposit layer. The plating bath used in this work is formed by nickel sulfamate and at a concentration of 400ml/l, nickel chloride (10g/l), boric acid (50g/l), Allbrite SLA (30cc/l) and Allbrite 703 (2cc/l). The selection of this composition is mainly due to the type of application we intend, that is to say, injection molds, even when the injection is made with fibreglass. Nickel sulfamate allows us to obtain an acceptable level of internal stresses in the shell (the tests gave results, for different process conditions, not superior to 50MPa and for optimum conditions around 2MPa). Nevertheless, such level of internal pressure is also a consequence of using as an additive Allbrite SLA, which is a stress reducer constituted by derivatives of toluenesulfonamide and by formaldehyde in aqueous solution. Such additive also favours the increase of the resistance of the shell when permitting a smaller grain. Allbrite 703 is an aqueous solution of biodegradable surface-acting agents that has been utilized to reduce the risk of pitting. Nickel chloride, in spite of being harmful for the internal stresses, is added to enhance the conductivity of the solution and to favour the uniformity in the metallic distribution in the cathode. The boric acid acts as a pH buffer. Once the bath has been defined, the operative parameters that have been altered for testing different conditions of the process have been the current density (between 1 and 22A/dm2), the temperature (between 35 and 55C) and the pH, partially modifying the bath composition. 4. Obtained hardnessOne of the most interesting conclusions obtained during the tests has been that the level of hardness of the different electroformed shells has remained at rather high and stable values. In Fig. 2, it can be observed the way in which for current density values between 2.5 and 22A/dm2, the hardness values range from 540 and 580HV, at pH 40.2 and with a temperature of 45C. If the pH of the bath is reduced at 3.5 and the temperature is 55C those values are above 520HV and below 560HV. This feature makes the tested bath different from other conventional ones composed by nickel sulfamate, allowing to operate with a wider range of values; nevertheless, such operativity will be limited depending on other factors, such as internal stress because its variability may condition the work at certain values of pH, current density or temperature. On the other hand, the hardness of a conventional sulfamate bath is between 200250HV, much lower than the one obtained in the tests. It is necessary to take into account that, for an injection mold, the hardness is acceptable starting from 300HV. Among the most usual materials for injection molds it is possible to find steel for improvement (290HV), steel for integral hardening (520595HV), casehardened steel (760800HV), etc., in such a way that it can be observed that the hardness levels of the nickel shells would be within the mediumhigh range of the materials for injection molds. The objection to the low ductility of the shell is compensated in such a way with the epoxy resin filling that would follow it because this is the one responsible for holding inwardly the pressure charges of the processes of plastics injection; this is the reason why it is necessary for the shell to have a thickness as homogeneous as possible (above a minimum value) and with absence of important failures such as pitting. Fig. 2.Hardness variation with current density. pH 40.2, T=45C.5. Metallographic structureIn order to analyze the metallographic structure, the values of current density and temperature were mainly modified. The samples were analyzed in frontal section and in transversal section (perpendicular to the deposition). For achieving a convenient preparation, they were conveniently encapsulated in resin, polished and etched in different stages with a mixture of acetic acid and nitric acid. The etches are carried out at intervals of 15, 25, 40 and 50s, after being polished again, in order to be observed afterwards in a metallographic microscope Olympus PME3-ADL 3.3/10. Before going on to comment the photographs shown in this article, it is necessary to say that the models used to manufacture the shells were made in a FDM rapid prototyping machine where the molten plastic material (ABS), that later solidifies, is settled layer by layer. In each layer, the extruder die leaves a thread approximately 0.15mm in diameter which is compacted horizontal and vertically with the thread settled inmediately after. Thus, in the surface it can be observed thin lines that indicate the roads followed by the head of the machine. These lines are going to act as a reference to indicate the reproducibility level of the nickel settled. The reproducibility of the model is going to be a fundamental element to evaluate a basic aspect of injection molds: the surface texture. The tested series are indicated in Table 1. Table 1. Tested series Series pH Temperature (C) Current density (A/dm2) 14.20.2552.2223.90.2455.5634.00.24510.0044.00.24522.22 Fig. 3 illustrates the surface of a sample of the series after the first etch. It shows the roads originated by the FDM machine, that is to say that there is a good reproducibility. It cannot be still noticed the rounded grain structure. In Fig. 4, series 2, after a second etch, it can be observed a line of the road in a way less clear than in the previous case. In Fig. 5, series 3 and 2 etch it begins to appear the rounded grain structure although it is very difficult to check the roads at this time. Besides, the most darkened areas indicate the presence of pitting by inadequate conditions of process and bath composition. Fig. 3.Series 1 (150), etch 1.Fig. 4.Series 2 (300), etch 2.Fig. 5.Series 3 (300), etch 2.This behavior indicates that, working at a low current density and a high temperature, shells with a good reproducibility of the model and with a small grain size are obtained, that is, adequate for the required application. If the analysis is carried out in a plane transversal to the deposition, it can be tested in all the samples and for all the conditions that the growth structure of the deposit is laminar (Fig. 6), what is very satisfactory to obtain a high mechanical resistance although at the expense of a low ductibility. This quality is due, above all, to the presence of the additives used because a nickel sulfamate bath without additives normally creates a fibrous and non-laminar structure. The modification until a nearly null value of the wetting agent gave as a result that the laminar structure was maintained in any case, that matter demonstrated that the determinant for such structure was the stress reducer (Allbrite SLA). On the other hand, it was also tested that the laminar structure varies according to the thickness of the layer in terms of the current density. Fig. 6.Plane transversal of series 2 (600), etch 2.6. Internal stressesOne of the main characteristic that a shell should have for its application like an insert is to have a low level of internal stresses. Different tests at different bath temperatures and current densities were done and a measure system rested on cathode flexural tensiometer method was used. A steel testing control was used with a side fixed and the other free (160mm length, 12.7mm width and thickness 0.3mm). Because the metallic deposition is only in one side the testing control has a mechanical strain (tensile or compressive stress) that allows to calculate the internal stresses. Stoney model was applied and was supposed that nickel substratum thickness is enough small (3m) to influence, in an elastic point of view, to the strained steel part. In all the tested cases the most value of internal stress was under 50MPa for extreme conditions and 2MPa for optimal conditions, an acceptable value for the required application. The conclusion is that the electrolitic bath allows to work at different conditions and parameters without a significant variation of internal stresses. 7. Test of the injection moldTests have been carried out with various representative thermoplastic materials such as PP, PA, HDPE and PC, and it has been analysed the properties of the injected parts such as dimensions, weight, resistance, rigidity and ductility. Mechanical properties were tested by tensile destructive tests and analysis by photoelasticity. About 500 injections were carried out on this core, remaining under conditions of withstanding many more. In general terms, important differences were not noticed between the behavior of the specimens obtained in the core and the ones from the machined cavity, for the set of the analysed materials. However in the analysis by photoelasticiy (Fig. 7) it was noticed a different tensional state between both types of specimens, basically due to differences in the heat transference and rigidity of the respective mold cavities. This difference explains the ductility variations more outstanding in the partially crystalline materials such as HDPE and PA 6. Fig. 7.Analysis by photoelasticity of injected specimens.For the case of HDPE in all the analysed tested tubes it was noticed a lower ductility in the specimens obtained in the nickel core, quantified about 30%. In the case of PA 6 this value was around 50%. 8. ConclusionsAfter consecutive tests and in different conditions it has been checked that the nickel sulfamate bath, with the utilized additives has allowed to obtain nickel shells with some mechanical properties acceptable for the required application, injection molds, that is to say, good reproducibility, high level of hardness and good mechanical resistance in terms of the resultant laminar structure. The mechanical deficiencies of the nickel shell will be partially replaced by the epoxy resin that finishes shaping the core for the injection mold, allowing to inject medium series of plastic parts with acceptable quality
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