模具外文翻譯塑料模具

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1、塑料在國民經(jīng)濟(jì)的多個領(lǐng)域中得到廣泛的應(yīng)用,而它的產(chǎn)量按體積計(jì)算在世界上已超過了鋼鐵的產(chǎn)量。同時(shí), 塑料模具是塑料成型加工中不可缺少的工具, 在總的模具產(chǎn)量中所占的例逐年增加, 在當(dāng)前已處于重要位置。在我國塑料模具的應(yīng)用在國民經(jīng)濟(jì)中的地位愈來愈重要。它的鋼材耗用量大, 品種規(guī)格多, 形狀復(fù)雜, 表面粗糙度值要求低, 制造難度大。因此, 探討塑料模具的制造中的選用材料與熱處理問題, 綜合分析其工作條件、失效、性能, 合理選用材料與熱處理以及提高它的使用壽命, 保證制件質(zhì)量,降低制造成本顯得非常重要。 1、塑料模具失效因素分析 (1) 一般模具失效因素分析 一般模具制造中包括模具設(shè)計(jì)、選用材料

2、、熱處理機(jī)械加工、調(diào)試與安裝等過程。根據(jù)調(diào)查表明: 模具失效的因素中, 模具所使用的材料與熱處理是影響使用壽命的主要因素 , 其比例約占70%,國內(nèi)外的有關(guān)資料也表明了相同的結(jié)果。從全面質(zhì)量管理的角度出發(fā), 不能把影響模具使用壽命的諸因素作為多項(xiàng)式之和來衡量, 而應(yīng)該是多因素的乘積, 這樣模具材料與熱處理的優(yōu)劣在整個模具制造過程中就顯得特別重要。 (2) 塑料模具失效因素分析 塑料模具的重要失效形式為磨損失效, 局部塑性變形失效和斷裂失效。 ①當(dāng)塑料模具使用的材料與熱處理不合理, 塑料模具的型腔表面硬度低, 而耐磨性差, 其表現(xiàn)為, 型腔面因磨損及變形引起的尺寸超差; 粗糙度值因拉毛而變

3、高, 表面質(zhì)量惡化。尤其是當(dāng)使用固態(tài)物料進(jìn)入塑模型腔, 它會加劇型腔面的磨損, 故塑料模產(chǎn)生了磨損失效。加之,塑料加工時(shí)含有氯、氟等成份受熱分解出腐蝕性氣體 HCl、HF, 使塑料模具型腔面產(chǎn)生腐蝕磨損, 形成侵蝕失效。 ②局部塑性變形失效。塑料模具所采用的材料強(qiáng)度與韌性不足, 變形抗力低; 當(dāng)填充的物料進(jìn)入塑模型腔內(nèi), 有超載、持續(xù)受熱, 周期受壓, 而應(yīng)力分布不均勻, 以及塑模型腔面硬化層過薄, 從而使塑模產(chǎn)生局部的塑性變形而引起的表面皺紋、凹陷、麻點(diǎn)棱角堆塌, 超過要求限度而造成失效以及回火不充分等因素使塑料模具壽命縮短, 過早的失效。 ③斷裂失效。塑料模具形狀復(fù)雜, 多棱角薄邊,應(yīng)

4、力嚴(yán)重集中在韌性不足之外。同時(shí), 塑料模采用合金工具鋼回火不充分, 而發(fā)生斷裂失效。 從塑料模三種失效形式可知: 選用合理的塑料模具材料與熱處理, 對它的使用壽命至關(guān)重要。故此,塑料模具材料的選用與熱處理應(yīng)滿足下列要求: A1較高的硬度、良好的耐磨性、型腔硬度要求在 HRC30～60, 淬火硬度大于 HRC55, 并且有足夠的硬化深度, 心部有足夠的強(qiáng)韌性, 以免脆斷, 塑性變形。 B1一定的抗熱性, 在 150～250 ℃長期工作, 不氧化、不變形, 尺寸穩(wěn)定性好。 C1注射時(shí), 有腐蝕介質(zhì)析出, 要求有一定的耐蝕性。 D1熱處理變形小, 對精密模具來說, 要求變形小于0105%,

5、 并且有足夠的淬透性。 E1切削加工性能好, 具有優(yōu)良的拋光, 耐磨性μ能, 鏡面拋光可達(dá) Ra 011 m以下。 F1 焊接性, 鍛造工藝性能良好1 2、塑料模具合理選材與熱處理的基準(zhǔn) 隨著對塑料模具的要求的提高, 對模具鋼材也提出了更多的要求。即希望提供更多、更好的具有高硬度鏡面加工性能好, 耐磨性能強(qiáng)的淬火, 回火類新鋼材。 但是, 還要根據(jù)塑料的類型以及對被成型的塑料制品的尺寸、精度、質(zhì)量、數(shù)量不同的要求, 并考慮已有制造模具的條件來選用不同類型的塑料模具鋼及其熱處理。 (1) 合理選用塑料模具鋼 表 1　塑料模具鋼的選用 工作條件 推薦鋼號 生產(chǎn)塑料產(chǎn)品批量較小,

6、 精度要求不高, 尺寸不大的模具 45、55鋼或10、20鋼滲碳 在使用過程中有較大的動載荷, 生產(chǎn)批量較大, 磨損嚴(yán)重 12CrNi3A、20Cr、20CrMnMo、 20Cr2Ni4A鋼滲碳 大型、復(fù)雜、批量較大、注射成型或擠壓成型模具 3Cr2Mo、4Cr3Mo3SiV、5CrNiMo、 5CrMnMo、4Cr5MoSiV、4Cr5M0SiV1、 熱固性成型及要求高耐磨、高強(qiáng)度、塑料模具 9Mn2V、7CrMn2WMo、CrWMn、 MnCrWV、GCr15、5Cr2MnWMoVs、Cr2 Mn2SiWMoV、Cr6WV、Cr12MoV、Cr12 耐腐蝕和高精度塑

7、料模具 4Cr13、9Cr18、Cr18MoV、 Cr14Mo、Cr14Mo4V 復(fù)雜、精密、高耐磨塑料模具 25CrNi3MoAL18Ni（250） 、 18Ni （300） 、18Ni （350） (2) 塑料模具鋼的熱處理 塑料模具如果采用常規(guī)的熱處理質(zhì)量無法保證,模具使用壽命短, 材料的利用率僅為 60%, 為此,對塑料模具中所使用的鋼材, 應(yīng)采用特別的熱處理,以延長塑模使用壽命。 對于要求心部具有高的強(qiáng)韌性和表面層的耐磨性的塑料模具, 可通過表面強(qiáng)化處理技術(shù), 提高耐磨性和使用壽命。然而表面強(qiáng)化技術(shù), 它不僅能提高塑模型腔表面的耐磨性, 而且能使塑模內(nèi)部保持足夠的強(qiáng)韌

8、性, 這對于改善塑料模的綜合性能, 節(jié)約合金元素, 大幅度降低成本, 充分發(fā)揮材料的潛力, 以及更好地利用新材料, 都是十分有效的, 實(shí)踐證明: 表面強(qiáng)化技術(shù)是提高塑模質(zhì)量和延長其使用壽命的主要途徑。 采用電火花表面強(qiáng)化技術(shù), 它是通過火花放電作用, 把一種導(dǎo)電材料（YT15、YT30） 涂敷及滲透到另一種導(dǎo)電鋼制模 45鋼 的表面上, 構(gòu)成合金化的表面層, 從而改變模具工作面的物理和化學(xué)性能的一種工藝方法。為了使被強(qiáng)化的45 鋼制模具的基體表面光潔, 事先必須將模具基體 45 鋼 的工作面和電極表面清洗干凈, 然后手握 D9110 強(qiáng)化機(jī)將電極 YT15、YT30 沿模具 45 鋼制作 工

9、作面移動, 并保持一定的壓力, 使火花放電均勻連續(xù)。經(jīng)電火化強(qiáng)化之后, 被強(qiáng)化表層 顯微 硬度可達(dá)HV1100～1400, 甚至更高。其強(qiáng)化層與結(jié)合牢固, 耐沖擊、不剝落。強(qiáng)化處理時(shí), 工件處于冷態(tài), 且放電點(diǎn)極小, 時(shí)間短, 沒有退火變形等現(xiàn)象, 這大大提高模具型腔面的耐熱性、耐磨性、熱硬性和耐蝕性,生產(chǎn)實(shí)踐證明, 經(jīng)電火花表面強(qiáng)化后, 擠出塑料模使用壽命可提高 1 倍以上, 強(qiáng)化層在使用過程中磨損后, 還可以重新進(jìn)行強(qiáng)化。 3 、塑料模選用材料的發(fā)展方向 塑料模具對鋼材的質(zhì)量和性能有一些特殊要求。例如: 熱處理變形小, 研磨與拋光性能好, 光潔度高, 有較強(qiáng)的花紋刻蝕性, 尺寸穩(wěn)定,

10、有別于其他模具材料, 尤其是型腔復(fù)雜, 高精度的塑料模具對模具的選材有更高的要求, 但模具鋼直接影響模具的壽命?，F(xiàn)有的國產(chǎn)傳統(tǒng)的模具鋼從品種質(zhì)量、性能等方面都不能滿足現(xiàn)代化的生產(chǎn)需求, 于是國內(nèi)又開發(fā)與研制了一些新型的塑料模具鋼, 以供選用。 （1） 5CrMnMoVSCo 5NiSCo 高韌性易切削料、模具鋼, 這種鋼材在國內(nèi)是首創(chuàng), 其切削加工性、等向性、韌性和可鍛性均好。 5NiMoSCo —預(yù)處理采用調(diào)質(zhì)工藝, 其淬火溫度為 890～900 ℃, 油淬之后, 硬度在 HRC60 以上, 650 ℃回火后, 予處理硬度為 HRC35, 其切削加工性同退火狀態(tài)的45 鋼, 可順利地進(jìn)

11、行多種切削加工。 (2) SM1 和 SM2 塑料模具鋼它屬于硫系易切削模具鋼, 用于要求高的注射模、壓鑄模, 效果良好。兩種模具鋼中的元素,S 以 MnS 型微粒夾雜存在, 可以起到減少切削力和易于斷屑的作用。SM 1鍛軋之后, 迅速退火, 而 SM2 則不用退火, 直接經(jīng)時(shí)效和預(yù)硬化處理可使用。二種鋼經(jīng)570 ℃氮化后, 心部基體強(qiáng)度不變, 表面硬度可達(dá) HV1100。SM2 可氮化與時(shí)效同時(shí)進(jìn)行。 4、國內(nèi)外塑料模具發(fā)展水平的比較 近年來確實(shí)發(fā)展很快 ,有些已達(dá)到或接近國際水平 ,尤其是隨著改革開放政策的不斷深入 ,“三資”企業(yè)蓬勃發(fā)展 ,對我國塑料模具設(shè)計(jì)制造水平的提高起到了非

12、常大的作用。然而 ,由于我國模具制造基礎(chǔ)薄弱 ,各地發(fā)展極不平衡 ,因此總體來看 ,與國際先進(jìn)水平相比和與國內(nèi)外市場需求相比 ,差距還很大。這主要表現(xiàn)在下列方面。 (1) 塑料模具產(chǎn)品水平 (2) 工藝裝備水平 我國塑料模制造企業(yè)設(shè)備數(shù)控化率和 CAD/CAM應(yīng)用覆蓋面比國外低得多 ,且設(shè)備不配套、利用率低的現(xiàn)象十分嚴(yán)重。國產(chǎn)設(shè)備在精度、加工表面粗糙度、剛性、穩(wěn)定性、可靠性及刀具和附件的配套性和精度保持 性等方面與國外相比仍有較大差距。 .(3)開發(fā)能力及經(jīng)濟(jì)效益等方面 國外模具企業(yè)技術(shù)人員比例很高 ,多數(shù)企業(yè)在5%以上 ,有些在 50%以上 ,有些企業(yè)往往是大多數(shù)職工可在技術(shù)與生

13、產(chǎn)崗位上互換 ,具有很高素質(zhì) ,加之企業(yè)對產(chǎn)品開發(fā)很重視 ,經(jīng)常與產(chǎn)品廠一起共同開發(fā)產(chǎn)品與模具 ,因此有很強(qiáng)的開發(fā)能力。我國模具企業(yè)技術(shù)人員比例低 ,多數(shù)企業(yè)在 10%～15%之間 ,且大多數(shù)只注重模具開發(fā) ,不重視產(chǎn)品開發(fā) ,因此綜合開發(fā)能力很低 ,在市場上常處于被動地位。經(jīng)濟(jì)效益方面 ,國外工業(yè)發(fā)達(dá)國家每個模具職工平均創(chuàng)造模具產(chǎn)值 15 萬～20 萬美元 ,而我國只有 4萬～5 萬元人民幣。國外模具企業(yè)大都有一定利潤 ,而我國模具企業(yè)大都是微利甚至虧損。 .(4 )管理及其他方面 國內(nèi)外模具企業(yè)管理上的差距十分明顯。管理上差距所帶來的問題往往比技術(shù)上的差距更為嚴(yán)重。利用計(jì)算機(jī)進(jìn)行科學(xué)管

14、理在國外企業(yè)中已十分廣泛 ,而國內(nèi)還很少采用。到目前為止 ,通過 ISO9000 認(rèn)證的模具企業(yè)全國還不到 1%。另外 ,諸如企業(yè)結(jié)構(gòu)、產(chǎn)品 結(jié)構(gòu)、技術(shù)結(jié)構(gòu)及企業(yè)運(yùn)營機(jī)制等方面 ,國內(nèi)外差距也較大。 .(5)產(chǎn)需矛盾 我國塑料模具市場總體上供不應(yīng)求 ,特別是大型、精密、復(fù)雜、長壽命塑料模產(chǎn)需矛盾十分突出 ,滿足率只有 60%左右。尤其是為工程塑料配套的模具 ,目前滿足率只有 40%左右。工程塑料是我國重點(diǎn)支持和優(yōu)先發(fā)展的產(chǎn)業(yè) ,預(yù)計(jì)每年將有 25%的增長率。為解決這個矛盾 ,每年只好大量進(jìn)口。1999 年共進(jìn)口塑模具約 4 億美元 ,其中絕大部分是塑料模具。

15、 Plastics in a number of areas of the national economy has been widely used, and its production by volume in the world has exceeded the output of iron and steel. At the same time, plastic mold plastic molding are an indispensable tool for the mold in the total production has increased year by

16、year the proportion of cases, in the present is in an important position. Plastic mold in China application status in the national economy more and more important. Its steel consumption, and many varieties of different specifications, the shape of complex, low value of surface roughness, manufacturi

17、ng difficult. Therefore, to explore the manufacture of plastic mold materials and heat treatment selection problem, a comprehensive analysis of their working conditions, failure, performance, a reasonable selection of materials and heat treatment, as well as improve its service life and ensure the q

18、uality of parts, reduce manufacturing costs it is very important. 1,Factor analysis of plastic mold (1) Factor analysis of the general failure die Included in the general mold die design, selection of materials, machining heat treatment, testing and installation process. According to the surve

19、y show that: Failure of the factors that mold, used mold materials and heat treatment are the main factors affect the life, the proportion of about 70% of the relevant information both at home and abroad also shows that the same results. Total quality management from the point of view of the impact

20、of mold should not put life as a polynomial of the factors and to measure, but are the product of many factors, such mold materials and heat treatment of the pros at the whole process of mold manufacturing it is particularly important. (2) Failure factors of plastic mold Plastic mold of the impo

21、rtant failure mode of failure for the wear and tear, failure of local plastic deformation and fracture failure. ① When the plastic mold materials and heat treatment used unreasonable, plastic mold cavity lower surface hardness, wear resistance and bad, and its performance for the cavity surface an

22、d deformation due to wear and tear caused by the size of super-bad; roughness value as a result of the change nap high, the deterioration of surface quality. Especially when the use of solid materials into plastic cavity model, it would aggravate the wear cavity surface, it produced a wear plastic f

23、ailure. In addition, plastic processing contain chlorine, fluorine and other corrosive elements of the heat decomposition gases HCl, HF, so that produce plastic mold cavity surface corrosion and wear, the formation of corrosion failure. ② local plastic deformation failure. Plastic mold material us

24、ed in inadequate strength and toughness, deformation resistance is low; when the filler material into the plastic model of the cavity, there is overloading, continuous heat, compression cycle, and non-uniform stress distribution, as well as the cavity surface-hardening plastic model had a thin layer

25、 so that local produce mold caused by plastic deformation of the surface wrinkles, dents, pitting angular heap collapsed, more than the requirements, as well as the limits of failure caused by such factors as inadequate tempering plastic mold to make shorten the life span of premature failure. ③ f

26、racture failure. Plastic mold the shape of complex, multi-corner thin edge, the stress on the toughness of a serious shortage. At the same time, the use of plastic alloy tool steel tempering inadequate fracture failure occurs. From the plastic shows the form of three types of failure: a reasonable

27、 choice of mold materials and heat treatment, it is essential for life. Therefore, the plastic mold material selection and heat treatment should meet the following requirements: A1 high hardness, good wear resistance, hardness cavity at HRC30 ~ 60, quenching the hardness more than HRC55, and there

28、 is enough depth of hardening, the center has sufficient strength and toughness to avoid brittle fracture, plastic deformation. The heat resistance must B1, 150 ~ 250 ℃ at the long-term, non-oxidized, non-deformation, good dimensional stability. C1 injection, precipitation has corrosive medium,

29、requires a certain degree of corrosion resistance. D1 deformation heat treatment of small, precision mold, the deformation is less than 0105 percent requirement, and there is sufficient hardenability. E1 good cutting performance, with excellent polishing, μ can wear, mirror-polished up to Ra 011

30、 m below. F1 welding and forging process in good 1 2, plastic mold materials and heat treatment of a reasonable benchmark Plastic mold with the requirements of the improvement of the steel mold made more demands. That wish to provide more and better processing of high-performance mirror good ha

31、rdness, wear resistance and strong quenching and tempering of new steel. However, also according to the type of plastic molding on the size of the plastic products, precision, quality, number of different requirements, taking into account the conditions have been manufacturing molds to choose diff

32、erent types of plastic mold steel and heat treatment. (1) a reasonable selection of plastic mold steel Table 1 Selection of Plastic Mold Steel working conditions Steel No. recommend The production of small quantities of plastic products, precision modest, size of the mold is not large 45,55

33、or 10,20 Steel Carburizing Steel In the use of the process there is a larger dynamic load, the production of larger quantities, wear serious 12CrNi3A, 20Cr, 20CrMnMo, Carburizing steel 20Cr2Ni4A Large, complex, large-volume, injection molding or extrusion mold 3Cr2Mo, 4Cr3Mo3SiV, 5CrNiMo,

34、 5CrMnMo, 4Cr5MoSiV, 4Cr5M0SiV1, Thermoset molding and high wear resistance, high strength, plastic mold 9Mn2V, 7CrMn2WMo, CrWMn, MnCrWV, GCr15, 5Cr2MnWMoVs, Cr2 Mn2SiWMoV, Cr6WV, Cr12MoV, Cr12 Corrosion resistance and high-precision plastic mold 4Cr13, 9Cr18, Cr18MoV, Cr14Mo, Cr14Mo4V

35、 Complex, sophisticated, high wear-resistant plastic mold 25CrNi3MoAL18Ni (250), 18Ni (300), 18Ni (350) (2)Heat treatment of plastic mold steel If the use of conventional plastic mold heat treatment can not guarantee the quality, mold short life, the utilization of material is only 60%, to that

36、 end, on the plastic mold used in the steel, special heat treatment should be used to extend mold life. Requirements of the center for high strength and toughness and wear resistance of the surface layer of the plastic mold can be enhanced through the surface treatment technology, improve wear res

37、istance and service life. However, surface hardening technology, which not only can improve the plastic model of the cavity surface resistance to abrasion, but also maintain enough internal mold of the strength and toughness, which is to improve the overall performance plastic, saving of alloying el

38、ements, a significant reduction in costs, and give full play to the potential of materials, as well as better use of new materials, are very effective, practical and proven: surface hardening technology is to improve the modeling quality and extending its life to the major route of transmission. E

39、DM surface hardening technology used, it is through the spark discharge effect, put a conductive material (YT15, YT30) coating and penetrate into a steel mold conductive surface 45 on steel, alloy composition of the surface layer, thereby to change the die face the physical and chemical properties o

40、f a process. Be enhanced in order to make 45 steel mold and smooth the surface of the substrate, must be pre-mold 45 steel substrate and the electrode surface of the face wash, and then machine will strengthen the hands D9110 electrode YT15, YT30 steel production along the die face 45 to move and ma

41、intain a certain degree of stress, so that continuous spark discharge uniformity. Enhanced by the electric cremation, the surface microhardness was enhanced up to HV1100 ~ 1400, or even higher. Enhanced layer and the combination of its strong, impact-resistant, non-peeling. Strengthening treatment,

42、the workpiece in the cold, and the discharge point is extremely small, time is short, there is no deformation phenomena such as annealing, which greatly enhance the heat-resistant mold cavity surface, and resistance to abrasion, hot hard and corrosion resistance, the production of practice has prove

43、d by the electric spark surface hardening, the plastic extrusion enhance the useful life of more than one, and strengthen the use of layers in the process of wear and tear, could also be re-strengthen. 3, plastic materials, the development direction of selection Plastic mold steel quality and pe

44、rformance has some special requirements. For example: small-deformation heat treatment, grinding and polishing good performance, finish high, there is a strong etching of the pattern, size, stability, and is different from the other mold materials, especially cavity are complex, high-precision plast

45、ic mold of the mold material there is higher requirements, but a direct impact on die steel die life. Made available from the traditional varieties of mold steel quality, performance and other aspects of the production can not meet the needs of modernization, and development and the development of d

46、omestic and some new type of plastic mold steel, selected for. (1) 5CrMnMoVSCo 5NiSCo free cutting high toughness materials, mold steel, this steel is the first in China, and its cutting, and isotropic, toughness and good forging of both. 5NiMoSCo - quenched and tempered the use of pre-treatment

47、 process, the quenching temperature of 890 ~ 900 ℃, oil quenching, the hardness of HRC60 or more 650 ℃ after tempering, to deal with hardness HRC35, cutting of their status with the annealing of the 45 steel, can be successfully carried out a variety of machining. (2) SM1 and SM2 plastic mold st

48、eel it is sulfur free cutting die steel grades for demanding injection mold, die-casting mold well. Two die steel elements, S-type particles to MnS inclusions exist, you can play to reduce the cutting force and the role of breaking easily. SM 1 after rolling forging, rapid annealing, annealing and S

49、M2 is not directly by the statute of limitations and pre-hardening treatment can be used. Two kinds of nitrided steel by 570 ℃, the intensity of the center of the matrix remains unchanged, the surface hardness of up to HV1100. Nitride and SM2 can be spent at the same time. 4, plastic mold at home a

50、nd abroad compared levels of development Indeed developed rapidly in recent years, some have reached or come close to international standards, especially with the policy of reform and opening up the deepening of the "three capital" enterprises to flourish, the plastic mold design and manufacture o

51、f our country level has played a very large role. However, because of the weak foundation of our mold manufacturing, throughout the development of extreme imbalance, so the whole, compared with the international advanced level and compared with the domestic and international market demand, the gap i

52、s still very great. This is mainly manifested in the following areas. (1) the level of plastic mold Products (2) the level of technique and equipment China plastic manufacturer of CNC equipment and CAD / CAM applications coverage is much lower than abroad, and the device does not support a low

53、 utilization rate of the very serious situation. China-made equipment at accuracy, surface roughness, rigidity, stability, reliability and cutting tools and accessories to maintain the accuracy of matching and With foreign countries, such as there is still a wide gap between compared. . (3) the

54、development of capabilities and cost-effectiveness, etc. Die enterprises abroad a high proportion of technical personnel, the majority of enterprises in more than 5%, some at more than 50%, some companies are often the majority of workers in technical and production on the exchange of posts, have

55、a very high-quality, in addition to business-to-product development is attention often works together with the product development of products and molds, so there is a strong development capability. Mold our country the proportion of enterprises with low technical staff, the majority of enterprises

56、at 10% ~ 15%, and most have only focused on the development of mold, do not attach importance to product development, capacity development is therefore very low, often in the market in a passive position. Economic benefits, the foreign industrial countries die each mold output value of the average 1

57、50,000 to create 20 million, and our country, only 4 million to 5 million yuan. Mold foreign enterprises must have a profit, and mold our country are low-profit enterprises or even losses. . (4) management and other aspects of Die at home and abroad on the gap between corporate management is obv

58、ious. On the gap between the management of the problems brought about by the technological gap, more often than not more serious. The use of computer science and management in foreign enterprises has been very extensive, and also seldom used internally. Up to now, the molds through the ISO9000 authe

59、ntication enterprise is less than 1% of the country. In addition, such as the enterprise structure, product Structure, technological structure and operating mechanism of enterprises, the gap between home and abroad as well. . (5) The production and demand contradiction Plastic mold our country

60、 on the overall market demand, especially for large, sophisticated, complex, long-life plastic production and demand very conspicuous contradictions, to meet the rate was only around 60%. Especially for supporting the mold engineering plastics currently meet only about 40%. Engineering Plastics are

61、the focus of our country to support and give priority to the development of the industry, will have an estimated annual growth rate of 25%. To resolve this conflict, but to a large number of imports each year. 1999 total imports of rubber molds of about 400 million U.S. dollars, most of which are plastic mold.