模具類畢業(yè)設(shè)計外文資料翻譯--塑料產(chǎn)品故障由于設(shè)計， 材料或處理問題

1、<p><b>　　外文資料翻譯：</b></p><p>　　PLASTIC PRODUCT FAILURE DUE TO DESIGN,MATERIAL OR PROCESSING PROBLEMS</p><p>　　By Myer Ezrin, Gary Lavigne and John Helwig University of Connecticu

2、t, Institute of Materials Science</p><p><b>　　Abstract</b></p><p>　　Several examples are given in which design, processing, or an aspect of the material were primary contributors to

3、failure of plastic products. A common pattern is failure to realize the consequences of seemingly inconsequential practices or decisions. Mold design was a factor in some cases. Material factors and processing were invol

4、ved in other cases. Frequently design, material and processing are so closely related that failure cannot be ascribed solely to one of the three (8).</p><p>　　1. Introduction</p><p>　　In many ca

5、ses of failure the cause is at least partly due to failure to know or realize the potential consequences of seemingly safe practices or decisions. In many of the cases cited failure occurs at the manufacturing stage, eit

6、her in primary processing, such as injection molding, or in secondary operations. All failures can be traced to the design, the material, or processing, assuming service conditions are not unusually severe. The interdepe

7、ndence of the three main causes of failure is such</p><p>　　2. Part Design</p><p>　　2.1 Polypropylene (PP) caps for a packaging application required that the top of the cap be flexed substantial

8、ly due to direct contact with a round ball at the top of the container. Fracture occurred with some caps from the high flexural load and deformation. The gate was at the center of the top of the cap where stress was grea

9、test in service. The design and material can withstand the service stresses only if the material properties are in control, which was not the case. Inadequate antioxidant</p><p>　　Presented at National Manuf

10、acturing Week, Design for Manufacturability of Plastic Parts, March 16, 1999, Chicago.</p><p>　　PLASTIC PRODUCT FAILURE DUE TO DESIGN, MATERIAL OR PROCESSING PROBLEMS</p><p>　　by Myer Ezrin, Gar

11、y Lavigne and John Helwig</p><p>　　2.2 An O ring made of plasticized PVC was in contact with a polycarbonate part in an assembly that required</p><p>　　that the PC move freely when the O ring pr

12、essure was removed. In service there was sticking, i.e., separation did not occur readily as designed. Plasticizer at the surface transferred to the PC, which is not completely impervious to plasticizer. In effect, the p

13、lasticizer became an adhesive between PC and PVC. This failure was probably also due in part to the fact that plasticizers are less compatible in PVC under pressure. In this case the effect of plasticizer on PC, an amorp

14、hous polymer, was </p><p>　　2.3 Bottle caps were spray painted for color and scratch resistance. The bottom of the caps were to be bonded to another part of the cap with silicone adhesive. The adhesive faile

15、d to bond to the plastic in some cases. The cause was that some spray paint contacted the bottom surface. Waxy ingredients in the paint, for scratch resistance, interfered with the bond that normally would have been made

16、 to the silicone. The design and processing did not take into account the need to protect the bottom </p><p>　　3. Mold Design</p><p>　　3.1 An ABS injection molded part of a syringe needle holder

17、 (4) consisted of two flats on the inside 180E</p><p>　　apart. A metal eyelet and tubing inserted after molding were held in place by stress at the flats. The design called for the flats, which are high stre

18、ss points, to be 90E removed from the part’s two weld lines. In some mold cavities the flats were not located as intended, so that the flats were at the weld lines, contributing to failure.</p><p>　　3.2 A ho

19、llow ABS injection molded part had a top ring of ABS ultrasonically welded into the inside</p><p>　　diameter of the part. Some welds had a protrusion at one point in the circumference, which was thought to b

20、e flash from the welding. These defects occurred with parts from one of a two cavity mold. Lowering the force of insertion of the top ring during welding did not eliminate all defects. Examination of molded parts for fro

21、zen-in stress by immersion in acetic acid (ASTM D1939) showed very little stress. A check for out of roundness showed that bad parts were out of round as much as ±0.0025", c</p><p>　　4. Material<

22、;/p><p>　　4.1 A glass-filled PBT (polybutylene terephthalate) part had a hole in the center in which a threaded metal</p><p>　　part moved freely back and forth. In oven aging at 160EC to simulate u

23、nder the hood automotive service the metal part lost its ability to move freely in the PBT part, which had shrunken slightly. Shrinkage was due mainly to further crystallization in service beyond the degree of crystallin

24、ity as molded. DSC showed that the heat of fusion increased approximately 20%, corresponding to a like increase in degree of crystallinity. The crystallinity developed on aging at 160EC is seen as a new peak at</p>

25、<p>　　4.2 A prototype part was machined from a block of plastic believed to be acetal homopolymer. It performed in trial runs in service below expectations. Consideration was being given to redesign or to a chang

26、e in</p><p>　　PLASTIC PRODUCT FAILURE DUE TO DESIGN, MATERIAL OR PROCESSING PROBLEMS</p><p>　　by Myer Ezrin, Gary Lavigne and John Helwig</p><p>　　material. A check of the material

27、by infrared spectroscopy and DSC showed that it was HDPE, not acetal. The trial run results were consistent with what would be expected of HDPE. The failure was in assuming incorrectly what the type of material was.</

28、p><p>　　5. Processing</p><p>　　As indicated in the Introduction, a common failure is not to realize that the most severe and potentially damaging stage in a plastic’s entire experience is the therm

29、al and mechanical stresses of processing. This problem is particularly serious for condensation polymers (nylon, PET, PC, PUR) and for polyolefins, although it is a problem for all materials. In the former case, hydrolys

30、is to lower MW can take place if water content is above about 0.01%. The requirement of practically complete dryne</p><p>　　5.1 In injection molding of a PC part requiring high resistance to outdoor exposure

31、, a deposit formed on</p><p>　　the mold, requiring shutdown and cleaning more often than was usually experienced with PC. It also contaminated the surface of the part. Analysis identified the deposit as a UV

32、 absorber present at a relatively high concentration because of the light stability requirement. It was near its compatibility limit and the high temperature and pressure of molding</p><p>　　deposited a smal

33、l amount each time. Over a two week period, what was not noticeable at first became a real problem. lower temperature might help reduce the problem, but change in amount or type of UV absorber may also be needed.</p&g

34、t;<p>　　5.2 A brominated hydrocarbon flame retardant in nylon 6 is making it difficult to process and to retain the</p><p>　　desired properties. Such materials act as flame retardants by decomposing a

35、nd releasing bromine (Br2) and hydrogen bromide (HBr), which act as a blanket to exclude air. But when the bromo compound does that during processing, even to a small extent, the HBr, in contact with any water present, b

36、ecomes H+Br-. H+ acid is a strong catalyst for hydrolysis of condensation polymers; nylon 6 is a polyamide (-NHCO-). Hydrolysis occurs at the nitrogen-carbon bond. Processing in this case is a virtual tigh</p><

37、;p>　　5.3 A polyurethane containing a metal carbonate for radiopacity gave porosity in extrusions. Analysis by</p><p>　　thermal desorption gas chromatography/mass spectroscopy (7) identified carbon dioxide

38、 in the extruded material. This was traced to the carbonate, which contained CO2 as received, and decomposed further in processing. Elimination of the problem is focusing on removing the initially present CO2 in the carb

39、onate and molding so as to cause very little to form during processing.</p><p>　　6. Summary</p><p>　　Successful manufacture of plastic parts is a far more complicated matter than may be realized

40、. The</p><p>　　technology involved cannot be used most effectively without knowledge of the basic organic chemistry and physical chemistry that underlie the materials, including polymers and additives, and t

41、he rheology that is involved in melt flow processing. A major category of failure has not been dealt with in this paper, i.e., orientation and frozen-in stress and the consequences in environmental stress-cracking, warpa

42、ge, etc. Orientation is affected very strongly by polymer molecular weight and compositi</p><p>　　PLASTIC PRODUCT FAILURE DUE TO DESIGN, MATERIAL OR PROCESSING PROBLEMS</p><p>　　by Myer Ezrin, G

43、ary Lavigne and John Helwig</p><p>　　which design and material affect processing and, in turn, how all three affect product performance is the underlying</p><p>　　cause of many plastic problems.

44、</p><p><b>　　譯文：</b></p><p>　　塑料產(chǎn)品故障由于設(shè)計， 材料或處理問題</p><p>　　由邁爾埃茲林，加里L(fēng)avigne和約翰埃爾格 康涅狄格大學(xué)，材料科學(xué)研究所 抽象 給出幾個例子中，設(shè)計，加工，或者是物質(zhì)方面的主要貢獻者 在塑料產(chǎn)品的失敗。一個常見的模式是無法實現(xiàn)的后果看似無關(guān)緊要的做法或決定。模具設(shè)計

45、是在某些情況下因素。物質(zhì)因素和加工都參與了 其他案件。常見的設(shè)計，材料和加工是如此密切相關(guān)，失敗不能完全歸咎于以一對三。 </p><p><b>　　1.介紹 </b></p><p>　　在許多情況下，失敗的原因至少部分是因無法知道或意識到的潛在后果 看似安全的行為或決定。在許多案例列舉失敗時，或者在生產(chǎn)階段 在初級加工，如注塑，或在二級操作。所有的失敗可以追溯到

46、設(shè)計， 材料，或加工，假設(shè)服務(wù)條件并不特別嚴重。這三個相互依存 失敗的主要原因是這樣的：往往都是貢獻者。材料和加工特別強烈的聯(lián)系。 該材料的貢獻失靈可能會在聚合物本身或在添加劑。在塑料加工規(guī)定 熱和機械應(yīng)力的經(jīng)常是最嚴重的一個部分將在其整個一生的經(jīng)驗。失敗 往往是由于在如何處理講嚴重缺乏和實現(xiàn)上的重大影響。 給出失敗的例子，由于零件設(shè)計，模具設(shè)計，材料選擇和加工。 </p><p><b>　　2.0零

47、件設(shè)計 </b></p><p>　　2.1 聚丙烯（PP）的上限為包裝應(yīng)用要求，該頂帽子被大幅彎曲,由于直接接觸在容器的頂部圓球。骨折的發(fā)生與一些帽高負荷和彎曲變形。那門卻是在那里的上限應(yīng)力最大的頂部中心服務(wù)。在設(shè)計和材料可以承受的服務(wù)強調(diào)只有在材料性能的控制，都是情況并非如此。抗氧化劑和不足進行再研磨使用分子正在走出重的主要原因控制。這一案例說明了如何輕易未能實現(xiàn)某些聚合物，尤其是聚丙烯，降解過

48、程中在處理和分子量（MW）的小型減少可能足以導(dǎo)致失敗。該設(shè)計所扮演一開始在該斷裂在大門口這本身就是弱者的一部分。在處理過程中具有重大影響，可監(jiān)視多少熔融指數(shù)或熔體流動速率增加處理。一般來說，在大多數(shù)情況下，超過10-20％的增長可能會太多，除非部分經(jīng)驗很少強調(diào)服務(wù)。在兆瓦相應(yīng)減少可能只有約5％，但可能以上的設(shè)計和服務(wù)講會容忍。幸而，熔融指數(shù)是一種簡便，敏感試驗其中注意到這一事實熔體粘度的優(yōu)點是對20,000兆瓦以上的3.4兆瓦的冪函數(shù)。

49、另一種相對簡單的測試，提供了有效的措施，抗氧化劑含量是氧化誘導(dǎo)時間掃描量熱法（DSC）（美國ASTM D3895）差別。這個測試特別適用于聚烯烴（聚乙烯，聚丙烯）。如果沒有足夠的抗氧化劑，PP和</p><p>　　2.2 O形圈的塑聚氯乙烯在接觸中的一個集會的一部分，需要聚碳酸酯籌委會自由移動時，O型圈的壓力已被取消。在服務(wù)有堅持，即不分離容易出現(xiàn)按設(shè)計。增塑劑在轉(zhuǎn)移到個人電腦，這是不完全不透水的表面增塑劑。

50、實際上，增塑劑成為PC機和PVC膠。這種失敗可能是由于還一部分這一事實是不兼容增塑劑在PVC壓力下（2）。在這種情況下，增塑劑的影響在PC，一無定形聚合物，沒有得到實現(xiàn)，以及對指數(shù)的壓力的影響。 ABS是也不利受由聚氯乙烯（3）增塑劑的接觸。 </p><p>　　2.3 瓶帽被噴涂顏色和耐劃傷油漆。底部的蓋子被人保稅的另一個與硅酮膠帽的一部分。膠粘劑沒有保證金，以在某些情況下塑料。該原因是，一些噴漆表面接觸的

51、底部。在涂料糯成分，為抗劃傷性，干擾了正常情況下已作出的硅債券。設(shè)計和加工并沒有采取考慮到需要保護的底面以上，而上限是噴油漆。它應(yīng)該已經(jīng)實現(xiàn)即使是微量污染物表面上可以減少粘結(jié)強度非常強烈。 </p><p><b>　　3.0模具設(shè)計 </b></p><p>　　3.1 的ABS注塑成型的一個注射器針頭的持有人的一部分成兩個組成單位。除了一個金屬管插入孔和成形后舉行

52、了應(yīng)力發(fā)生在單位。所謂的設(shè)計 單位，這是高應(yīng)力點，可從兩個部分拆除抯焊接線90E。在某些模具腔 單位未設(shè)應(yīng)有作用，使單位在焊縫線條，造成失敗。 </p><p>　　3.2 ABS的注塑中空部分有ABS的頂環(huán)超聲波焊接成內(nèi) 直徑的部分。一些曾在焊接中的一個圓周，這被認為是一個突出閃點 從焊接。這些缺陷的發(fā)生，以一個兩腔模具1件。降低插入力 在頂部環(huán)焊接過程并沒有消除所有的缺陷?？荚嚨哪Ｋ懿考鼋Y(jié)在應(yīng)力 在乙酸（

53、美國ASTM D1939浸泡）顯示非常小的壓力。一種新的圓度進行檢查表明，壞件出了多達正負0.0025：“一輪相比正負0005”的好的地方。圖1是一個跨部門的觀點 交界處的一個焊接打磨焊接裝置獲得了1。失敗是對成型零件外側(cè)壁骨折， 只發(fā)生圓零件了。圖2是一個如何好的和壞的零件配合插入一起素描。 斷裂是由于閃存作為推進環(huán)插入的部分向外邊緣被迫下降。在所有焊縫良好 向下移動的閃存內(nèi)的一部分。在這種情況下，人類的失敗是不檢查的零件或模具型腔

54、是完美的圓形。 </p><p><b>　　4.0材料 </b></p><p>　　4.1 玻璃填充型PBT（聚對苯二甲酸乙二醇酯）的一部分，在一中心孔，其中一個線程金屬部分自由移動來回。在160EC老化爐在模擬引擎蓋下的金屬部分汽車服務(wù)喪失了行動能力，在PBT的一部分，這已略有萎縮自由。收縮，主要是因為進一步在服務(wù)結(jié)晶超出了作為塑造結(jié)晶度。 DSC分析表明，融

55、合熱增加約20％，相當(dāng)于在結(jié)晶度如增加（圖3）。發(fā)達的結(jié)晶就在160EC老化被看作是一個新的高峰大約200EC。如果不發(fā)生收縮的部分完全結(jié)晶。它不會是一個問題，如果合適或容忍金屬和塑料之間的不那么緊?？赡苁窃赑BT的成核劑將給予完全的結(jié)晶如模壓，模制，使萎縮的服務(wù)就不會發(fā)生。什么是沒有意識到的是，結(jié)晶聚合物可能萎縮，服務(wù)，如果不能完全結(jié)晶。 </p><p>　　4.2 原型的部分是加工從相信為均聚物縮醛塑料塊

56、。它試運行中表現(xiàn)低于預(yù)期的服務(wù)。目前正在考慮重新設(shè)計或改變在塑膠制品衰竭的設(shè)計，材料或處理問題由邁爾埃茲林，加里L(fēng)avigne和約翰埃爾格材料。作者通過紅外光譜和DSC材料檢查表明，這是高密度聚乙烯，不縮醛。審判運行結(jié)果與HDPE的會是什么預(yù)期相符。在假設(shè)的失敗是什么錯誤 </p><p><b>　　材料類型。 </b></p><p><b>　　5.0

57、加工 </b></p><p>　　如導(dǎo)言，一個共同的失敗表示不認識到，最嚴重的潛在在一個塑料抯整個經(jīng)驗損害階段是處理熱和機械應(yīng)力。此問題尤其凝結(jié)聚合物（尼龍，聚酯，電腦，聚氨酯）和聚烯烴嚴重，盡管這是一個問題所有材料。在前者情況下，可水解降低兆瓦，如果發(fā)生上述含水量約0.01％以上。在幾乎完全干燥的熔體要求怎么強調(diào)也不過分。對于像體育與聚烯烴聚丙烯，氧氣是敵人，連同（碳原子自由基反應(yīng)缺乏一個氫原子）

58、。沒有適當(dāng)和有效的抗氧化劑，對失敗的舞臺設(shè)置在成型機或擠出機。第2.1節(jié)，是指3.4權(quán)力關(guān)系熔體粘度和兆瓦。因為即使一小在兆瓦增加，熔體粘度刑罰為高，使加工更困難。在同一時間，性能曲線（強度，韌性，耐化學(xué)性）與兆瓦趨于穩(wěn)定（6），因此在產(chǎn)品收益性能可能會犧牲一些加工高昂的代價。這個教訓(xùn)似乎是設(shè)計，使性能可以在可能的最低兆瓦（最高心肌梗塞實現(xiàn)）。相互依存的設(shè)計，材料和加工是非常高的。這是說在某些情況下以上。 </p><

59、;p>　　5.1 在注射成型的PC要求高耐戶外曝光，形成存款的一部分模具，需要關(guān)閉和清理往往比通常是與PC經(jīng)驗。它也污染了表面的部分。分析確定的存款作為一個在相對高濃度的紫外線吸收劑存在，因為光的穩(wěn)定性要求。這是近其兼容性限制和高溫度和成型壓力 </p><p>　　存放少量每次。過去兩個星期的時間，什么不是明顯在首次成為一個真正的問題。在較低溫度下成型，可能有助于減少問題，但變化在數(shù)量或類型可能也紫外線

60、吸收劑是必要的。 </p><p>　　5.2 溴化烴尼龍6阻燃是難以處理和保留所需的屬性。這種材料作為阻燃劑的分解和釋放溴（溴）和氫銨（HBR）的，它作為一個毯子行為以排除空氣。但是，當(dāng)溴化合物確實，在加工，甚至一個小的程度上，HBr的，與目前的任何水接觸，成為氫離子溴。氫離子酸水解是一個強大的催化劑縮合聚合物;尼龍6聚酰胺（- NHCO -）。發(fā)生在水解氮，碳鍵。在這種情況下處理是一個虛擬的走鋼絲。 <

61、;/p><p>　　5.3 包含一個聚氨酯顯影金屬碳酸鹽中擠出了孔隙度。分析熱解吸氣相色譜/質(zhì)譜（7）中確定的擠壓材料的二氧化碳。這追蹤到的碳酸鹽，其中載有截至收到二氧化碳，并進一步分解處理。消除問題的重點是消除目前二氧化碳在最初的碳酸鹽和成型，從而導(dǎo)致很少在加工過程中形成。 </p><p><b>　　6.0綜述 </b></p><p>　

62、　塑料零件制造成功是一種更為復(fù)雜的事情比可能會實現(xiàn)。該涉及的技術(shù)不能用于未經(jīng)基本有機化學(xué)和物理知識的最有效化學(xué)所依據(jù)的材料，包括聚合物和添加劑，以及所涉及的熔體流動的流變學(xué)處理。一個失敗的主要類別有沒有處理這個文件，即方向和冷凍的壓力和在環(huán)境應(yīng)力開裂，翹曲等方向的后果是非常強烈的影響聚合物分子量和組成，以及處理;設(shè)計也起到了重要作用。不理解的方式塑料產(chǎn)品故障由于設(shè)計，材料或處理問題由邁爾埃茲林，加里L(fēng)avigne和約翰埃爾格它的設(shè)計和材