749 瓶塞注射模設計（有cad圖+文獻翻譯）
749 瓶塞注射模設計（有cad圖+文獻翻譯）,749,瓶塞注射模設計（有cad圖+文獻翻譯）,瓶塞,注射,設計,cad,文獻,翻譯
A technical note on the characterization of electroformed nickel shells for their application to injection molds
——Universidad de Las Palmas de Gran Canaria, Departamento de Ingenieria Mecanica, Spain
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 Outline
1. 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
References
1. Introduction
One 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 [1], [2] and [3], 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 [3], 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 mold
The 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 [4] 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.
The stages to obtain a core [4], 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 equipment
Electrodeposition [5] and [6] 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 [7] and [8] at a concentration of 400?ml/l, nickel chloride (10?g/l), boric acid (50?g/l), Allbrite SLA (30?cc/l) and Allbrite 703 (2?cc/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 50?MPa and for optimum conditions around 2?MPa). 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.
The equipment used to manufacture the nickel shells tested has been as follows:
? Polypropylene tank: 600?mm?×?400?mm?×?500?mm in size.
? Three teflon resistors, each one with 800?W.
? Mechanical stirring system of the cathode.
? System for recirculation and filtration of the bath formed by a pump and a polypropylene filter.
? Charging rectifier. Maximum intensity in continuous 50?A and continuous current voltage between 0 and 16?V.
? Titanium basket with nickel anodes (Inco S-Rounds Electrolytic Nickel) with a purity of 99%.
? Gases aspiration system.
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 22?A/dm2), the temperature (between 35 and 55?°C) and the pH, partially modifying the bath composition.
4. Obtained hardness
One 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 22?A/dm2, the hardness values range from 540 and 580?HV, at pH 4?±?0.2 and with a temperature of 45?°C. If the pH of the bath is reduced at 3.5 and the temperature is 55?°C those values are above 520?HV and below 560?HV. 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 200–250?HV, 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 300?HV. Among the most usual materials for injection molds it is possible to find steel for improvement (290?HV), steel for integral hardening (520–595?HV), casehardened steel (760–800?HV), etc., in such a way that it can be observed that the hardness levels of the nickel shells would be within the medium–high 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.
5. Metallographic structure
In 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 50?s, 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 0.15?mm 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.
Table 1.
Tested series
Series
pH
Temperature (°C)
Current density (A/dm2)
1
4.2?±?0.2
55
2.22
2
3.9?±?0.2
45
5.56
3
4.0?±?0.2
45
10.00
4
4.0?±?0.2
45
22.22
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.
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 [9]. 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.
6. Internal stresses
One 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 (160?mm length, 12.7?mm width and thickness 0.3?mm). 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 [10] was applied and was supposed that nickel substratum thickness is enough small (3?μm) 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 50?MPa for extreme conditions and 2?MPa 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 mold
Tests 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.
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. Conclusions
After 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 levels.
References
[1] A.E.W. Rennie, C.E. Bocking and G.R. Bennet, Electroforming of rapid prototyping mandrels for electro discharge machining electrodes, J. Mater. Process. Technol. 110 (2001), pp. 186–196. [2] P.K.D.V. Yarlagadda, I.P. Ilyas and P. Chrstodoulou, Development of rapid tooling for sheet metal drawing using nickel electroforming and stereo lithography processes, J. Mater. Process. Technol. 111 (2001), pp. 286–294.
[3] J. Hart, A. Watson, Electroforming: A largely unrecognised but expanding vital industry, Interfinish 96, 14 World Congress, Birmingham, UK, 1996.
[4] M. Monzón et al., Aplicación del electroconformado en la fabricación rápida de moldes de inyección, Revista de Plásticos Modernos. 84 (2002), p. 557.
[5] L.F. Hamilton et al., Cálculos de Química Analítica, McGraw Hill (1989).
[6] E. Julve, Electrodeposición 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 Development Institute (1989).
[9] J. Dini, Electrodeposition Materials Science of Coating and Substrates, Noyes Publications (1993).
[10] J.W. Judy, Magnetic microactuators with polysilicon flexures, Masters Report, Department of EECS, University of California, Berkeley, 1994. (cap′. 3).
外文資料譯文
注塑成型優(yōu)化方法
tuncayerzurumlua和巴布爾ozcelik
廠房及制造工程,伊利諾斯工學院41400、科賈埃利,土耳其
摘 要
快速成型技術及快速模具發(fā)達國家已廣泛在過去幾年. 在這篇文章中,作為一種程序,使電芯塑料注射模具分析. 貝殼制成模型,通過快速成型得到利用差分系統(tǒng). 主要目的是分析力學特征鎳炮彈、 學習方面的不同金相組織,硬度,內(nèi)部講,可能失敗 由這些特色的有關參數(shù)以生產(chǎn)貝殼電設備. 終于引爆了一個核心注塑模具.
文章概要
1. 引言
2. 注塑模具制造過程中的
3. 殼牌獲取電:設備
4. 獲得硬度
5. 金相組織
6. 測試的注塑模具
7. 結論
參考資料
1、引言
其中最重要的是現(xiàn)代工業(yè)遇到的挑戰(zhàn)是提供更好的產(chǎn)品與消費者,優(yōu)秀品種和時間變異(新設計). 因此,現(xiàn)代工業(yè)必須有更多的競爭性和生產(chǎn)成本與接受. 毫無疑問,結合時間變量,質(zhì)量并不容易,因為他們經(jīng)常變狀態(tài) 互相; 科技進步生產(chǎn)許可證制度,將可更有效和可行的組合在 方式,例如,如果是演化的觀測系統(tǒng)和注塑技術、 我們得出的結論是,事實上 需少時間把新產(chǎn)品的市場和較高素質(zhì). 快速模具制造技術,在這一領域, 其中的技術進步,使得有可能改善設計和制造過程注入部分. 快速模具制造技術基本上是由程序集將允許我們獲取 塑料模具零件,小型系列 在短短的時間里,以可接受的精度水平. 其應用領域不僅包括制作塑膠件注[1],[2],[3]但是, 的確,這是他們研制并在那里找到更多的最高產(chǎn)量
本文包括在科研第一線,廣泛試圖研究確定,分析測試和建議 在產(chǎn)業(yè)層次,形成核心的可能性注塑模具從獲取鎳炮彈、 同時,作為一個初步的原型取得了差分模型快速成型設備
它也將不得不說,事前并沒有任何新電鑄技術的應用,因為它 業(yè)內(nèi)人士無數(shù)、 但這種試圖調(diào)查研究工作,并在多大程度上使用這一技術參數(shù),其中 在生產(chǎn)技術上的快速模具. 所有在準確、制度化的方式方法的運用,并提出了工作.
2、注塑模具制造過程中的核心是由鎳殼薄,透過電進程 這是一個充滿金屬環(huán)氧樹脂主管期間一體化這一核心板塊[4] 模具(圖1)制造許可證直接注射A型多用標本、 他們確定的甲狀旁腺恩的SO3167標準. 目的是要確定這個試樣力學性能的材料收集代表工業(yè) 在注入這些工具及其性能相比常規(guī)手段獲得
該階段取得核心根據(jù)這一方法研制工作,有以下幾方面:
(一) 在設計CAD系統(tǒng)預期目標
(二) 在快速原型制造設備模型(差分系統(tǒng)). 該材料將ABS塑料
(三) 生產(chǎn)鎳電殼牌從以往的模式已經(jīng)涂了導電涂料 事前(必須有導電).
(四) 清理殼牌從模型
(五) 生產(chǎn)核心填寫背面與殼牌環(huán)氧樹脂抗高溫 隨著銅管與冷凍槽
有兩個空洞的注塑模具、 他們一個是電加工的核心,一是直接在移動壓板. 因此,它獲得了與同一工具及同一工藝條件、 同時注入兩種不同制成標本蛀牙技術.
3、殼牌獲取電設備電鍍[5]和[6]是一個電化學過程中的化學變化,當它起源于一電解質(zhì) 悠悠電流通過. 該電鍍[5]和[6]是一個電化學過程中的化學變化,當它起源于一電解質(zhì) 悠悠電流通過. 該電解槽是由金屬鹽兩個電極淹沒,一個陽極(鎳)、陰極(示范) 它是通過把烈度來自直流. 當電流流經(jīng)電路 目前在金屬離子的溶液轉化為原子,是定居于創(chuàng)造一個更加陰極 存款少或制服層
鍍液采用這項工作是由鎳、磺酸[7][8]集中在400 毫升/公升,氯化鎳(10微克/公升)、硼酸(50微克/公升),allbrite習得(30完工/公升),703allbrite(2完工/公升). 選擇這種組合主要原因是我們打算申請類別,即 注塑模具,即使注射了玻璃纖維. 磺酸鎳讓我們獲得可以接受的程度,在內(nèi)部講殼牌(作了測試結果 不同工藝條件,不高于50兆帕的最佳條件和2兆帕左右). 不過,這種程度的內(nèi)部壓力也是作為添加劑使用后果allbrite習得、 這是由衍生-T強調(diào)消脂、甲醛水溶液. 這種添加劑也贊成增加阻力較小殼當允許糧食. 703allbrite是降解水溶液表面代理商代理已經(jīng)利用以減少蝕. 氯化鎳,盡管危害性的內(nèi)部講 加上增強導電溶液并贊成在金屬均勻分布在 陰極. 硼酸pH值的作為緩沖
該設備用于制造鎳炮彈已測試如下：
● 聚丙烯坦克:600毫米×400毫米×500毫米的尺寸
● 三聚四氟乙烯電阻器,每一個有800
● 特約陰極機械攪拌系統(tǒng)
● 再循環(huán)和過濾系統(tǒng)組成的水泵、浴聚丙烯過濾
● 充電整流器. 最高強度和持續(xù)不斷的電流電壓0至16伏
● 鎳鈦籃 陽極(鎳礦公司的S輪電解鎳)具有純度99%
● 氣體吸入系統(tǒng)
一旦已確定浴、 手術已更改參數(shù)測試不同條件的過程一直電流密度(之間 1、22℃),溫度(35至55℃)和pH值,改變鍍液組成部分
4、獲得硬度
一個非常有趣的測試期間已獲得結論,對不同程度的硬度 電炮彈一直保持在相當高的穩(wěn)定價值觀. 在無花果. 2,可以觀察到哪種方式電流密度值為2.5和22℃之間, 硬度值從高壓540、580、 在pH0.2和4+攝氏45℃ 如果是浴的pH值為3.5,氣溫下降55℃以上這些價值觀 高壓520以下560高壓. 這一特點使得測試洗澡不同于其他傳統(tǒng)業(yè)務組成磺酸鎳、 允許經(jīng)營范圍更廣的價值觀念; 然而,這種有限性的將取決于其他因素, 例如內(nèi)應力,因為其工作狀況可能在某些變性的pH值、 電流密度和溫度. 在另一方面,傳統(tǒng)的硬度介于200-250高壓磺酸浴、 遠比取得的一個考驗. 既要考慮到,對注塑模具、硬度接受高壓300起. 其中最常見的材料就可以找到注塑模具鋼改善(高壓290) 積分硬化鋼(高壓520-595),casehardened鋼(高壓760-800)等 這樣可以觀察到的硬度水平都將炮彈鎳 中高幅度的注塑模具材料. 反對低延性是有償殼牌這樣的環(huán)氧樹脂填充 它表示,將依負責,因為這是一個內(nèi)心壓力控股收費進程 注塑; 這也是為什么必須要由有殼厚度為盡可能均勻(以上 最低值),。
5、金相組織
為了分析金相結構、電流密度、溫度值,主要是改良. 樣品分析、橫向組額葉組(垂直于沉積). 實現(xiàn)便捷的準備,他們在方便的封裝樹脂 巧言鐫刻在不同階段有硝酸、醋酸混合物. 瓶子的進行每隔15,25,40,50收盤后擦拭, 為了觀察事后在奧林匹斯金相顯微鏡碲
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