球形塑料包装盒注塑模具设计【一模四腔】【说明书+CAD】
收藏
资源目录
压缩包内文档预览:(预览前20页/共30页)
编号:78025138
类型:共享资源
大小:2.43MB
格式:ZIP
上传时间:2020-05-08
上传人:柒哥
认证信息
个人认证
杨**(实名认证)
湖南
IP属地:湖南
50
积分
- 关 键 词:
-
一模四腔
说明书+CAD
球形
塑料包装
注塑
模具设计
说明书
CAD
- 资源描述:
-
购买设计请充值后下载,,资源目录下的文件所见即所得,都可以点开预览,,资料完整,充值下载可得到资源目录里的所有文件。。。【注】:dwg后缀为CAD图纸,doc,docx为WORD文档,原稿无水印,可编辑。。。具体请见文件预览,有不明白之处,可咨询QQ:12401814
- 内容简介:
-
Abstract Injection moulding is one of the most versatile and important operation for mass production of plastic parts. In this process, cooling system design is very important as it largely determines the cycle time. A good cooling system design can reduce cycle time and achieve dimensional stability of the part. This paper describes a new square sectioned conformal cooling channel system for injection moulding dies. Both simulation and experimental verification have been done with these new cooling channels system. Comparative analysis has been done for an industrial part, a plastic bowel, with conventional cooling channels using the Moldflow simulation software. Experimental verification has been done for a test plastic part with mini injection moulding machine. Comparative results are presented based on temperature distribution on mould surface and cooling time or freezing time of the plastic part. The results provide a uniform temperature distribution with reduced freezing time and hence reduction in cycle time for the plastic part. Index TermsConformal cooling channel, Cycle time Moldflow, Square shape. I. INTRODUCTION Injection moulding is a widely used manufacturing process in the production of plastic parts 1. The basic principle of injection moulding is that a solid polymer is molten and injected into a cavity inside a mould which is then cooled and the part is ejected from the machine. Therefore the main phases in an injection moulding process involve filling, cooling and ejection. The cost-effectiveness of the process is mainly dependent on the time spent on the moulding cycle in which the cooling phase is the most significant step. Time spent on cooling cycle determines the rate at which parts are produced. Since, in most modern industries, time and costs are strongly linked, the longer is the time to produce parts the more are the costs. A reduction in the time spent on cooling the part would drastically increase the production rate as well as reduce costs. So it is important to understand and optimize the heat transfer process within a typical moulding process. The rate of the heat exchange between the injected plastic and the mould is a decisive factor in the economical performance of an injection mould A B M Saifullah is a research doctoral student at Industrial Research Institute Swinburne (IRIS), Swinburne University of Technology, Melbourne, Australia (e-mail- .au), also Member, IAENG. S. H. Masood is a Professor of Mechanical & Manufacturing Engineering at Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, Melbourne, Australia. (Corresponding author, ph:+61-3-9214 8260, fax: +61-3-9214 5050, e-mail: .au) Dr Igor Sbarski is a Senior Lecturer at Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, Melbourne, Australia.(e-mail: .au ). .Heat has to be taken away from the plastic material until a stable state has been reached, which permits demolding. The time needed to accomplish this is called cooling time or freezing time of the part. Proper design of cooling system is necessary for optimum heat transfer process between the melted plastic material and the mould. Traditionally, this has been achieved by creating several straight holes inside the mould core and cavity and then forcing a cooling fluid (i.e. water) to circulate and conduct the excess heat away from the molten plastic. The methods used for producing these holes rely on the conventional machining process such as straight drilling, which is incapable of producing complicated contour-like channels or anything vaguely in 3D space. An alternative method of cooling system that conforms or fits to the shape of the cavity and core of the mould can provide better heat transfer in injection moulding process, and hence can result in optimum cycle time. This alternative method uses contour-like channels of different cross-section, constructed as close as possible to the surface of the mould to increase the heat absorption away from the molten plastic. This ensures that the part is cooled uniformly as well as more efficiently. Now-a-days, with the advent of rapid prototyping technology such as Direct Metal Deposition (DMD), Direct Metal Laser Sintering (DMLS) and many advanced computer aided engineering (CAE) software, more efficient cooling channels can be designed and manufactured in the mould with many complex layout and cross-sections2,3,4. This paper presents a square section conformal cooling channel (SSCCC) for injection moulding die. Simulation has been done for an industrial plastic part, a circular plastic bowel for these SSCCC and compared with conventional straight cooling channels (CSCC) with Moldflow Plastic Inside (MPI) software. Comparative experimental verification has also been performed with SSCCC and CSCC die for a circular shape test part with mini injection moulding machine for two plastic materials. Result shows that SSCCC die gives better cooling time and temperature distribution than that of CSCC dies. II. DESIGN OF THE PART AND MOULDS A. Part design The part circular plastic bowl made of polypropylene (PP) thermoplastic, as shown in Fig 1(a) has been designed with Pro-Engineer CAD software. It was then exported to IGES (Initial Graphics Exchange Specification) file surface model to import in MPI for analysis. Material volume of the plastic part is 177.90cm3 and its weight is 162.3 gm. Experimental test part as shown in Fig 1(b) has also been designed with Pro-Engineer software. Experimental New Cooling Channel Design for Injection Moulding A B M Saifullah, S.H. Masood and Igor Sbarski Proceedings of the World Congress on Engineering 2009 Vol IWCE 2009, July 1 - 3, 2009, London, U.K.ISBN: 978-988-17012-5-1WCE 2009 verification has been done with two types of plastic materials, PP and ABS (Acrylonitrile Butadiene Styrene). Test part volume was 8.8 cm3, and part weight for ABS and PP were 8.68 gm and 8.13gm respectively. (a) (b) Fig-1 CAD model of (a) Circular plastic bowel, (b) Test part. B. Mould Design Mould design has been done using Pro/Moldesign module of the Pro/Engineer system. This mould is then manufactured with Computer Numerical Control (CNC) machine. The mould shown in Fig 2 has two parts, the core and the cavity. Square section conformal cooling channel (SSCCC) has been produced around the cavity by CNC machining of one half of the channel on cavity part and the other half on the core part. Both halves are then joined with screws and sealed with liquid gasket (Permatex) to avoid water leakage. Fig-2 Assembly CAD model of mould with core (top) and two cavity parts. III. ANALYSIS AND RESULTS MPI simulation software has been used for part analysis 5. Analysis sequence was flow-cool-warp. Polypropylene plastic material has been used for analysis. Comparative analysis has been done with conventional straight cooling channel (CSCC) and SSCCC. The diameter of CSCC was 12 mm and the length of SSCCC section size was 12 mm (Fig 3). Fusion meshing with global edge length of 0.995 cm has been used. The numbers of mesh elements used were 12944 and 12291 for CSCC and SSCCC respectively. (a) (b) Fig-3 Analysis setting in MPI (a) CSCC (b) SSCCC Both cases used cooling medium as normal water of 25C. Reynolds number was 10000, melting temperature was 230 C. Comparative analysis result from MPI as shown in Fig 4 shows that SSCCC shows better temperature distribution and (a) (b) Fig-4 Comparative freezing or cooling time (a) CSCC (b) SSCCC. less part freezing time than CSCC. In case of CSCC, most of the part cools in about 24 second except the top few areas, while on the other hand SSCCC diagram shows that it is less than 20 seconds. And also CSCC shows the time to freeze range to be 0.46-93.7sec and SSCCC shows this to be 0.3-87.15sec. So, using SSCCC, 5 second of cooling time has been reduced which is 35% reduction of cooling time. IV. EXPERIMENTAL VERIFICATION AND RESULTS Experimental verification has been done with a circular shape plastic test part using the machined mould as shown in Fig 5. Part diameter was 40 mm and thickness was 7 mm. The mould dimension was 10x10x2.5 cm3. Mould material was mild steel. Experiment has been done with a mini (a) (b) Fig-5 (a) Mild steel Core (left) and cavity with SSCCC (b) CSCC of mild steel. Proceedings of the World Congress on Engineering 2009 Vol IWCE 2009, July 1 - 3, 2009, London, U.K.ISBN: 978-988-17012-5-1WCE 2009 injection moulding machine of TECHSOFT mini moulder (Fig 6). Two thermocouples TC08 K type of PICO technology have been used to measure temperature of top and bottom surface of the test part. Melting temperature was 250C for both ABS and PP. Normal water has been used as a cooling medium, room temperature has been measured as 25 C, so is cooling water. Cooling channel diameter was 5 mm for CSCC and SSCCC section size was 5 mm. With two thermocouples, surface temperature of the test part has been measured for every second. Fig-6 Experimental setup for test injection moulding, left: mini moulder, right: temperature output in PC. Fig 7 and Fig 8 show the comparative temperature distribution for top and bottom surface of the plastic parts for 30 second. Fig-7 Comparative temperature plot for ABS From Fig 7 it is noted that for the ABS plastic, using SSCCC, the top face and bottom face of test part cooled earlier than that with CSCC. In case of SSCCC, maximum top and bottom surface temperature recorded at particular time immediately after injection were 53.36 C and 52.1C. After 30 second, this temperature reduced to 42.47 C and 43.07 C, whereas, for CSCC they were 53.24, 52.01 and 47.47, 47.72 C. So in average, 4 to 5 C reduction in temperature happens using the SSCCC. Similar results also have been found when using PP as the part material. From Fig 8, it can be shown that using SSCCC, about 2 to 3C reduction in temperature can be possible. Fig-8 Comparative temperature plot for PP In experimental tests, twenty sample test parts have been produced for ABS and PP material for experimental verification and in every case almost the same data has been found. Fig 9 shows the sample test parts in ABS and PP, which have been produced for experimental verification. Fig-9 Sample test part produced for experimental verification Left: ABS right: PP plastic. V. CONCLUSION The cooling process is one of the most important sub processes in injection moulding because it normally accounts for approximately half of the total cycle time and affects directly the shrinkage, bending and warpage of the moulded plastic product. Therefore, designing a good cooling channel system in the mould is crucial since it influences the production rate and quality. The results of MPI simulation and experimental verification show that using square shape conformal cooling channels gives up to 35% reduction in cooling time and 20% of the total cycle time can be obtained, thus greatly improving the production rate and the production quality of injection moulded parts. ACKNOWLEDGMENT These authors are grateful to Mrs. Meredith and Phil Watson of Faculty of Engineering and Industrial Science, Swinburne University of Technology for their technical support for die making with CNC machining. Proceedings of the World Congress on Engineering 2009 Vol IWCE 2009, July 1 - 3, 2009, London, U.K.ISBN: 978-988-17012-5-1WCE 2009 REFERENCES 1 D.V. Rosato, D.V. Rosato and M.G. Rosato, Injection Moulding Handbook-3rd ed , Boston, Kluwer Academic Publishers, (2003). 2 X. Xu, E. Sach and S.Allen, The Design of Conformal Cooling Channels In Injection Moulding Tooling,Polymer Engineering and Science, 4, 1, pp 1269-1272, (2001). 3 D.E. Dimla, M. Camilotto, and F. Miani: Design and optimization of conformal cooling channels in injection moulding tools, J. of Mater. Processing Technology, 164-165, pp 1294-1300, (2005). 4 A B M Saifullah and S. H. Masood, Optimum cooling channels design and Thermal analysis of an Injection moulded plastic part mould, Materials Science Forum, Vols. 561-565, pp. 1999-2002, (2007). 5 A B Saifullah, S. H. Masood and Igor Sbarski, cycle time optimization and part quality improvement using novel cooling channels in plastic injection moulding. ANTECNPE 2009, USA. Proceedings of the World Congress on Engineering 2009 Vol IWCE 2009, July 1 - 3, 2009, London, U.K.ISBN: 978-988-17012-5-1WCE 2009毕业设计(论文)外文资料翻译系 别 机电信息系 专 业 机械设计制造及其自动化 班 级 B070203 姓 名 王 飞 学 号 B07020319 指导老师 千学明 外文出处Proceedings of the World Congress on Engineering 2009 Vol I WCE 2009,July 1-3,2009 ,london,U.K. 附 件1. 原文:New Cooling Channel Design for for Injection Moulding 2.译文:新型注塑模具冷却通道设计 2011年3月12日New Cooling Channel Design for Injection MouldingA B M Saifullah, S.H. Masood and Igor Sbarski AbstractInjection moulding is one of the most versatile and important operation for mass production of plastic parts. In this process, cooling system design is very important as it largely determines the cycle time. A good cooling system design can reduce cycle time and achieve dimensional stability of the part. This paper describes a new square sectioned conformal cooling channel system for injection moulding dies. Both simulation and experimental verification have been done with these new cooling channels system. Comparative analysis has been done for an industrial part, a plastic bowel, with conventional cooling channels using the Moldflow simulation software. Experimental verification has been done for a test plastic part with mini injection moulding machine. Comparative results are presented based on temperature distribution on mould surface and cooling time or freezing time of the plastic part. The results provide a uniform temperature distribution with reduced freezing time and hence reduction in cycle time for the plastic part.Injection moulding is a widely used manufacturing process in the production of plastic parts 1. The basic principle of injection moulding is that a solid polymer is molten and injected into a cavity inside a mould which is then cooled and the part is ejected from the machine. Therefore the main phases in an injection moulding process involve filling, cooling and ejection. The cost-effectiveness of the process is mainly dependent on the time spent on the moulding cycle in which the cooling phase is the most significant step. Time spent on cooling cycle determines the rate at which parts are produced. Since, in most modern industries, time and costs are strongly linked, the longer is the time to produce parts the more are the costs. A reduction in the time spent on cooling the part would drastically increase the production rate as well as reduce costs. So it is important to understand and optimize the heat transfer process within a typical moulding process. The rate of the heat exchange between the injected plastic and the mould is a decisive factor in the economical performance of an injection mould.A B M Saifullah is a research doctoral student at Industrial Research Institute Swinburne (IRIS), Swinburne University of Technology, Melbourne,Australia (e-mail- .au), also Member, IAENG. S. H. Masood is a Professor of Mechanical & Manufacturing Engineering at Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, Melbourne, Australia. (Corresponding author, ph:+61-3-9214 8260, fax: +61-3-9214 5050, e-mail: .au) Dr Igor Sbarski is a Senior Lecturer at Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, Melbourne, Australia.(e-mail: .au ).Heat has to be taken away from the plastic material until a stable state has been reached, which permits demolding. The time needed to accomplish this is called cooling time or freezing time of the part. Proper design of cooling system is necessary for optimum heat transfer process between the melted plastic material and the mould. Traditionally, this has been achieved by creating several straight holes inside the mould core and cavity and then forcing a cooling fluid (i.e. water) to circulate and conduct the excess heat away from the molten plastic. The methods used for producing these holes rely on the conventional machining process such as straight drilling, which is incapable of producing complicated contour-like channels or anything vaguely in 3D space.An alternative method of cooling system that conforms or fits to the shape of the cavity and core of the mould can provide better heat transfer in injection moulding process, and hence can result in optimum cycle time. This alternative method uses contour-like channels of different cross-section, constructed as close as possible to the surface of the mould to increase the heat absorption away from the molten plastic. This ensures that the part is cooled uniformly as well as more efficiently. Now-a-days, with the advent of rapid prototyping technology such as Direct Metal Deposition (DMD), Direct Metal Laser Sintering (DMLS) and many advanced computer aided engineering (CAE) software, more efficient cooling channels can be designed and manufactured in the mould with many complex layout and cross-sections2,3,4. This paper presents a square section conformal cooling channel (SSCCC) for injection moulding die. Simulation has been done for an industrial plastic part, a circular plastic bowel for these SSCCC and compared with conventional straight cooling channels (CSCC) with Moldflow Plastic Inside (MPI) software. Comparative experimental verification has also been performed with SSCCC and CSCC die for a circular shape test part with mini injection moulding machine for two plastic materials. Result shows that SSCCC die gives better cooling time and temperature distribution than that of CSCC dies.II. DESIGN OF THE PART AND MOULDS A.Part design The part circular plastic bowl made of polypropylene (PP) thermoplastic, as shown in Fig 1(a) has been designed with Pro-Engineer CAD software. It was then exported to IGES (Initial Graphics Exchange Specification) file surface model to import in MPI for analysis. Material volume of the plastic part is 177.90cm3 and its weight is 162.3 gm. Experimental test part as shown in Fig 1(b) has also been designed with Pro-Engineer software. Experimental verification has been done with two types of plastic materials, PP and ABS (Acrylonitrile Butadiene Styrene). Test part volume was 8.8 cm3, and part weight for ABS and PP were 8.68 gm and 8.13gm respectively. B.Mould Design Mould design has been done using Pro/Molde sign module of the Pro/Engineer system. This mould is then manufactured with Computer Numerical Control (CNC) machine. The mould shown in Fig 2 has two parts, the core and the cavity. Square section conformal cooling channel (SSCCC) has been produced around the cavity by CNC machining of one half of the channel on cavity part and the other half on the core part. Both halves are then joined with screws and sealed with liquid gasket (Permatex) to avoid water leakage. III. ANALYSIS AND RESULTS MPI simulation software has been used for part analysis 5. Analysis sequence was flow-cool-warp. Polypropylene plastic material has been used for analysis. Comparative analysis has been done with conventional straight cooling channel (CSCC) and SSCCC. The diameter of CSCC was 12 mm and the length of SSCCC section size was 12 mm (Fig 3). Fusion meshing with global edge length of 0.995 cm has been used. The numbers of mesh elements used were 12944 and 12291 for CSCC and SSCCC respectively. Both cases used cooling medium as normal water of 25C Reynolds number was 10000, melting temperature was 230 C. Comparative analysis result from MPI as shown in Fig 4 shows that SSCCC shows better temperature distribution and less part freezing time than CSCC. In case of CSCC, most of the part cools in about 24 second except the top few areas, while on the other hand SSCCC diagram shows that it is less than 20 seconds. And also CSCC shows the time to freeze range to be sec and SSCCC shows this to be 0.3-87.15sec. So, using SSCCC, 5 second of cooling time has been reduced which is 35% reduction of cooling time.III. ANALYSIS AND RESULTS MPI simulation software has been used for part analysis 5. Analysis sequence was flow-cool-warp. Polypropylene plastic material has been used for analysis. Comparative analysis has been done with conventional straight cooling channel (CSCC) and SSCCC. The diameter of CSCC was 12 mm and the length of SSCCC section size was 12 mm (Fig 3). Fusion meshing with global edge length of 0.995 cm has been used. The numbers of mesh elements used were 12944 and 12291 for CSCC and SSCCC respectively. Both cases used cooling medium as normal water of 25C Reynolds number was 10000, melting temperature was 230 C. Comparative analysis result from MPI as shown in Fig 4 shows that SSCCC shows better temperature distribution and less part freezing time than CSCC. In case of CSCC, most of the part cools in about 24 second except the top few areas, while on the other hand SSCCC diagram shows that it is less than 20 seconds. And also CSCC shows the time to freeze range to be sec and SSCCC shows this to be 0.3-87.15sec. So, using SSCCC, 5 second of cooling time has been reduced whimeIV. EXPERIMENTAL VERIFICATION AND RESULTS Experimental verification has been done with a circular shape plastic test part using the machined mould as shown in Fig 5. Part diameter was 40 mm and thickness was 7 mm. The mould dimension was 10x10x2.5 cm3. Mould material was mild steel. Experiment has been done with a mini injection moulding machine of TECHSOFT mini moulder (Fig 6). Two thermocouples TC08 K type of PICO technology have been used to measure temperature of top and bottom surface of the test part. Melting temperature was 250C for both ABS and PP. Normal water has been used as a cooling medium, room temperature has been measured as 25 C, so is cooling water. Cooling channel diameter was 5 mm for CSCC and SSCCC section size was 5 mm. With two thermocouples, surface temperature of the test part has been measured for every second. From Fig 7 it is noted that for the ABS plastic, using SSCCC, the top face and bottom face of test part cooled earlier than that with CSCC. In case of SSCCC, maximum top and bottom surface temperature recorded at particular time immediately after injection were 53.36 C and 52.1C. After 30 second, this temperature reduced to 42.47 C and 43.07 C, whereas, for CSCC they were 53.24, 52.01 and 47.47, 47.72 C. So in average, 4 to 5 C reduction in temperature happens using the SSCCC. Similar results also have been found when using PP as the part material. From Fig 8, it can be shown that using SSCCC, about 2 to 3C reduction in temperature can be possible. In experimental tests, twenty sample test parts have been produced for ABS and PP material for experimental verification and in every case almost the same data has been found. Fig 9 shows the sample test parts in ABS and PP, which have been produced for experimental verification.V. CONCLUSION The cooling process is one of the most important sub processes in injection moulding because it normally accounts for approximately half of the total cycle time and affects directly the shrinkage, bending and warpage of the moulded plastic product. Therefore, designing a good cooling channel system in the mould is crucial since it influences the production rate and quality. The results of MPI simulation and experimental verification show that using square shape conformal cooling channels gives up to 35% reduction in cooling time and 20% of the total cycle time can be obtained, thus greatly improving the production rate and the production quality of injection moulded parts.ACKNOWLEDGMENT These authors are grateful to Mrs. and Phil Watson of Faculty of Engineering and Industrial Science, Swinburne University of Technology for their technical support for die making with CNC machining. REFERENCES 1 D.V. Rosato, D.V. Rosato and M.G. Rosato, Injection Moulding Handbook-3rd ed , Boston, Kluwer Academic Publishers, (2003). 2 X. Xu, E. Sach and S.Allen, The Design of Conformal Cooling Channels In Injection Moulding Tooling,Polymer Engineering and Science, 4, 1, pp 1269-1272, (2001). 3 D.E. Dimla, M. Camilotto, and F. Miani: Design and optimization of conformal cooling channels in injection moulding tools, J. of Mater. Processing Technology, 164-165, pp 1294-1300, (2005). 4 A B M Saifullah and S. H. Masood, Optimum cooling channels design and Thermal analysis of an Injection moulded plastic part mould, Materials Science Forum, Vols. 561-565, pp. 1999-2002, (2007). 5 A B Saifullah, S. H. Masood and Igor Sbarski, cycle time optimization and part quality improvement using novel cooling channels in plastic injection moulding. ANTECNPE 2009, USA. 新型注塑模具冷却通道设计作者A B M Saifullah, S.H. Masood 和 Igor Sbarski摘要注塑成型是大规模生产塑料零件时最通用并且最重要一种操作方法。在此项工艺当中,冷却系统的设计好坏是非常重要的,因为它很大程度上决定了零件的生产周期。一个良好的冷却系统设计可减少生产周期,并保证零件的尺寸稳定性。本文叙述的是一个注塑膜的冷却通道系统的横切面内容。对这些新的冷却通道系统进行模拟实验。工业园区采用比较分析法,用注塑仿真分析软件分析塑料内部,内部有常见的冷却通道。微注射成型机的塑料零件已得到实验验证。用模具表面温度的分布情况和塑料零件的冷却时间,或是凝固时间相比较分析得到的。结果表明,均匀的温度分布可减少凝固时间,从而减少塑料零件成型周期。1.介绍注塑成型的方法广泛使用于塑料部件的工艺生产当中 1。注射成型的基本原理是,一个固体聚合物熔化后,注入到模具型腔内,冷却之后脱模。因此,主要阶段是注射成型,过程包括填充、冷却和脱模。塑模周期决定生产成本效益高低,而冷却过程是尤为重要的一步。冷却周期决定部件生产效率。因此,在现代工业当中,生产成本和生产时间有密切关系,生产部件的时间越久,成本越高。减少冷却时间可在根本上增加生产效率,并且减少生产成本。因此,理解和优化典型的成型过程即内传热是很重要的。热交换率是塑料注射制品和模具的决定性因素,影响注塑模具的生产业绩。A B M Saifullah是工业研究机构的一名博士生会员, 就读于斯威本国立科技大学,澳大利亚墨尔本人,电子邮件:.au。IAENG. S. H. Masood的是斯威本国立科技大学机械制造工程系的一名教授, 澳大利亚墨尔本人。联系电话:+ 61-3-9214 8260,传真:+ 61-3-9214 5050,电子邮件:.auIgor Sbarski博士是斯威本国立科技大学机
- 温馨提示:
1: 本站所有资源如无特殊说明,都需要本地电脑安装OFFICE2007和PDF阅读器。图纸软件为CAD,CAXA,PROE,UG,SolidWorks等.压缩文件请下载最新的WinRAR软件解压。
2: 本站的文档不包含任何第三方提供的附件图纸等,如果需要附件,请联系上传者。文件的所有权益归上传用户所有。
3.本站RAR压缩包中若带图纸,网页内容里面会有图纸预览,若没有图纸预览就没有图纸。
4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
5. 人人文库网仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对用户上传分享的文档内容本身不做任何修改或编辑,并不能对任何下载内容负责。
6. 下载文件中如有侵权或不适当内容,请与我们联系,我们立即纠正。
7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。

人人文库网所有资源均是用户自行上传分享,仅供网友学习交流,未经上传用户书面授权,请勿作他用。