Abstract—Virtual manufacturing is introduced to the production process of E-Blocks of computer disk drives, which mainly includes the technologies of digital modeling, computer simulation and structural optimization. The Secondary development technology of CAD (computer aided design) is used to improve the efficiency of digital modeling. The trial period is cut down after the FEM (finite element method) is applied to the process of experimental cutting tool and structural modal simulation. The intelligence of virtual manufacturing is improved by using the technology of CAM (Computer Aided Manufacturing), which includes the strategy manager and the machining process simulation. The application shows that the trial period of E-Blocks of Computer Disk Drives is shorten nearly 50% by introducing virtual manufacturing.

I. INTRODUCTION IRTUAL manufacturing have gone through more than 20 years, which has been greatly developed and many applications had been widely expanded. Many institutes,

schools and companies are all in incessant research. In 1995, the decentralized multi-node distributed virtual manufacturing (DVM) was emphasized in a report about "national advanced manufacturing test-bed of the conceptual design plans" provided by the United States Institute of Standards and Technology. And in the report about "Manufacturing in information technology " by United States National Research Council , virtual manufacturing should includes the product integration, process design, shop floor control, virtual factories, and other information technology issues. And the advanced vehicle technology group of Ford Company introduced the virtual manufacturing for assembly simulation and virtual shape to improve aerodynamics, ergonomics and surface modeling. In China, the research and practical applications based on virtual manufacturing are all nearly in initial stage. The theories on virtual manufacturing have not been closed. Also, the engineering applications is also few. In particular, virtual manufacturing includes many softwares, such as CAD/CAM/CAE/CAPP, simulation software, modeling technology. The study in China most Concentrates in the system framework and integration, but the key technologies on application should be given more

Manuscript received April 1 10, 2010. This work was supported in part This work was supported in part by the The Shandong Province excellent young scientist funded project (BS2009ZZ016), Technology Development Program of Shandong Province Y2007F15,(2008GG1004006),The Open lab funded project of advanced manufacuturing technology of Guangxi province(0842006_038_K),The Yantai University excellent young scientist funded project (JX08Z6).

Yongsheng Chai, is with School of Electromechanical Automobile Engineering, Yantai University , Yantai, 264005, CHINA ,phone: 010-0535-6905130; fax: 010-0535-6902402; e-mail: chaiysh@163.com ).

Yulan Zhou, is with School of Electromechanical Automobile Engineering, Yantai University , Yantai, 264005, CHINA ,phone: 010-0535-6905130; fax: 010-0535-6902402; e-mail: cyszyl@163.com).

attention [1-3]. With the promotion of the computer, the industry of hard

disk drives has grown rapidly. E-Blocks of computer disk Drives, as shown in figure 1, work as the computer disk’s key component. The hard drive technology progresses more quickly, more new requirements proposed. The production of E-Blocks is a type of typical mass production. Although the company we studied only products a several types of E-Blocks, its production occupies nearly 30% or more in global production. Intense competition in the industry, making companies be more and more deeply awarded of that the traditional design, processing and production methods is difficult to meet the needs of the rapid development. Only by introducing new manufacturing technologies and concepts, a breakthrough will have been produced to achieve a higher status in production of competitive advantage and to obtain maximum economic benefits [4-8].

Fig. 1 the construction of disk

Now the suppliers of E-Blocks mainly take the role of

make-to-order. According to available drawings and quality requirements, they must quickly provide the trial samples and determine the completion and acceptance cycles. This makes the suppliers of E-Blocks to face the following problems:

(1) It is difficult to optimizing the complex structure of E-Blocks;

(2) The higher precision is being required to them; (3) The stringent quality requirements call for 100 %; (4) the complex and difficult processing technology and

experiments that includes higher cost and longer cycle trial, so the processing design is out of touch with the processing of trial;

(5) Relying on manual processing of NC code preparation, inefficient and easy to making error, and more difficult for programming of complex parts.

Virtual manufacturing technology being used in E-Blocks has to be an inevitable choice to enhance enterprise efficiency

E-Blocks of Computer Disk Drives based on Virtual ManufacturingYongsheng Chai, Yulan Zhou, Kun Wang

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Third International Workshop on Advanced Computational Intelligence August 25-27, 2010 - Suzhou, Jiangsu, China

978-1-4244-6337-4/10/$26.00 @2010 IEEE

[9, 10].

II. ANALYSIS OF MANUFACTURING PROCESS OF E-BLOCKS

The development process of E-Blocks on Virtual manufacturing includes five steps: digital modeling, physical cutting simulation, geometric processing simulation, static structure simulation and product trial.

A. Digital Modeling The Digital models mainly include: the digital model of

product, the digital model of special fixture, the digital model of tools. Digital modeling is the basis for virtual manufacturing. The manufacturing process starts from the time of receiving orders of parts drawings and quality requirements, which are two-dimensional engineering drawings faxed. Engineers have to reconstruct three-dimensional model by 3D CAD software. In the phase, the designer and staffs have to carry out strictly in accordance with user needs, and timely contact to customers to ensure the model’s correctness and accuracy. Along with the rapid development of the hard disk industry, the products upgrade very quickly. So it is key for versions of the digital product model management in the stage. Although different customers used different product, but there is no large difference among them. Each product requires special fixtures and tools, which requires that the design of fixture and tool have to be digital. Especially, the principle used similar figures for secondary development of CAD design, which will shorten the time of the digital modeling.

B. Physical Cutting Simulation Physical cutting simulation consists of three steps:

designing trial tools, cutting simulation and experiments. Physical cutting simulation of virtual manufacturing is to enhance the efficiency of a critical stage:

(1)As the industry characteristics, a large number of products are measured to 10 million, while most of the tools are the combination of specific tools. So the cost of tool consumption products occupies large proportion;

(2) Cutting rate of the tools not only for the quality of the products have a great impact, but also seriously constrained the processing efficiency of products.

Physical cutting shows as follow: First, the digital product modeling is completed by the tool designers, according to the structural characteristics of components such as blade design; Second, the model will be cut with simulation software to adjust the tool .The key parameters of design and cutting carry out the physical cutting tool simulation; the final tool in accordance with established custom tool design parameters is the machine of cutting tool on the actual test to verify the design of cutting simulation results and evaluation of the deviation, to feedback to the kind of knife design further amended so as to provide an accurate tool for mass customization parameters.

C. Geometric Machining Simulation Geometric Machining Simulation is one of core technologies of the virtual manufacturing. The process

mainly includes the process scheduling, geometric simulation and NC program. When the digital model completed, engineers conduct process planning according the structural characteristics of components and requirements of processing quality. In the planning process, by process knowledge, special fixtures and tools of information, the manufacturing process comes out roughly. After the process scheduling finished, the digital simulation of model will be deal with in CAM. First, the preprocess will be completed by the process scheduling settings, tool selection, tool parameter configuration, fixture assembly, and machine parameters; second, each process will be simulated that it will deal the problems of collision detection and over-cutting. last, the entire product simulation processes are combined to form a complete simulation result. When the geometric simulation finished, G code of CNC will be generated for CNC machine. Through the ethernet, trial NC code will be sent to machine.

III. KEY TECHNOLOGIES OF E-BLOCKS ON VIRTUAL MANUFACTURING

The manufacturing process of E-Blocks involved in many technologies. And any one of technology will affect the final product quality, which is the plight of one of the virtual manufacturing technology. Only the virtual manufacture matched the actual manufacture of the product, it will achieve the reduction costs in development, shorten development cycles and improve product quality purposes.

A. The Intelligent of Modeling and Simulation One of the goals of virtual manufacturing is to increase

production preparation efficiency and reduce resource costs, which requires improving intelligent of modeling and simulation.

To build rapidly digital models, the digital product model, and tool and fixture models seriously restricts the conduct of the other stages. Intelligent modeling has been taken into the key research technologies.

(1) Similar figures theory will be used by collect all the designer's intelligence ,such as product classification, different modeling methods to summarize and draw conclusions, to explore a practical methods of modeling similar figures;

(2)For the model with the implicit rules, and rules of the mathematical abstraction, especially in jigs and tools. The establishment of the rule and knowledge base will be designed in modeling processes, by program design and development, the friendly interface reduces the designer’s technical requirements and improves design efficiency.

Simulation technology, especially the geometric processing of simulation is carried out strictly accordance with the digital models. The figure remained the same model of machine tools both models changes in the frequency of the lower fixture model, as well as changes in frequency of faster product model. Digital product model, due to the initial design phase, there are a number of factors may occur repeatedly fine-tuning, which makes processing of the simulation tool to ensure geometric path in line with the product to become a vital link. Two technologies mainly are

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used to solve this problem: (1) Characteristics associated with the use of technology,

create a tool path processing, the use of feature recognition technology, product model features built to adjust the scheduling process to ensure that generate tool paths in line with the product model . Thus making fine-tuning when the product model is only required for automatic updates, which can be realized linkage;

(2) Processing strategies are used to enhance the geometric simulation efficiency, through the geometric characteristics of the product analysis, similar characteristics, especially the use of similar tools and the same processing process approach, the establishment of processing strategies, allowing simulation of staff, direct use of the initial processing of the simulation strategy to enhance the degree of automation (as show in figure 2).

Fig. 2 The Intelligent process of Simulation

B. Construction of an Integrated platform System integration platform is the basis of virtual

manufacturing for disk drive worked on. System integration is one of the most optimized design of a comprehensive co-ordination requires a lot of technical support, including computer software, hardware, operating system technology, database technology, network information and so on, need to take into account the overall situation of the relationship between the different subsystems, research the various sub - the relationship between the interface between the systems.

System integration will be achieved - the best overall performance, that is, all parts and components together, not only after the work, and the whole system is a low-cost, high efficiency, performance, symmetrical, scalable and maintainable systems. But for general business, the acquisition is complete simulation analysis software system, a high-cost inputs, and that no professional staff can make these the role of the software works very well..

The PDM system is a perfect solution to the problem as a key factor. However, in practice, due to lack of corporate resources in this regard, for which, in particular, has designed a document management for all virtual manufacturing integrated platform. For virtual manufacturing involving the various departments and personnel to carry out information exchange to provide a unified management interface. Through the integration platform, the relevant authority may be based on their own to obtain the required information and its timely treatment, in particular, the digital model to date.

C. The Unified Virtual Simulation and Test Unified virtual manufacturing by using virtual simulation

and testing is difficult but a key point to a large extent, which determines their unified virtual manufacturing technology success or failure in the implementation. Regardless of how the virtual simulation is precise and perfect, ultimately must return to the production practice to carry out inspection. In particular, much production will perfect the simulation results, by using simulation to improve test quality, and achieve their organic unity, that enhances the competitiveness of enterprises in an effective way. The virtual manufacturing process of E-Blocks in three main simulations to solve their unity, in the course of the operation is mainly carried out as following:

(1) The establishment of simulation and test data against the database, for each simulation ,test results analysis and summary, from which to explore the reasons causing the difference, especially about the design parameters and simulation are closely related to a number of factors, which will test the cost effective precipitation, the formation of corporate intangible assets;

(2)The departments of simulation and experimental should break the traditional department's barriers. by using twinning mechanism, personnel simulation time and personnel testing to communicate, which ensure the provision of virtual manufacturing industrial solid foundation for efficient and consistent.

D. The Implementation of E-Blocks on Virtual Manufacturing The implementation process of E-Blocks on virtual

manufacturing is divided into three steps: modeling and processing of digital simulation and physical simulation. Through the current application status of CAD/CAE/CAM and technical staff level in virtual manufacturing enterprises plan to invest funds for research and analysis, and from the plight of starting the implementation of virtual manufacturing and, ultimately, a set of practical business tailored programs.

The CAD tools for enterprise software applications in the company we researched are used for a few engineers in the

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use of UG and Pro/E for three-dimensional modeling. But a large number of engineers are in use of Solidworks, and it’s also the company and most of the clients interact with a database platform. So for the finalization of Solidworks digital Design Company based platform for modeling, all what related to the key models are required. In order to enhance the design efficiency in CAD, two aspects are taken as following:

(1)By using multiple exploration and comparison, two-dimensional engineering drawings to be finalized. And the program of reconstruction of three-dimensional model, using solidwors in the view matching principle, directly to the three basic view of the two-dimensional engineering drawings .And the location of space matching characteristics will be constructed by using solidwors stretch, removal and scanning methods, which can quickly build a product model;

(2) Fixture and tool design process, via solidworks provide secondary development interface to the same series products. The product may correspond to a mathematical tool to model abstraction allows designers to improve the design efficiency.

Fig. 3 A machining tool path step of working simulation

In the CAM, the enterprise technology division mainly used MarstCAM, which absence the restrictions on technical strength, serious restricts the production, the most serious bottleneck in the enterprise. From the receipt of orders to provide customers with a general cycle model will not out of two weeks, in those days more than half of the time spends on the CAM. The main reason follows:

(1) Prior to the NC programming generally requires the designer to provide two-dimensional drawings or three-dimensional model into two-dimensional drawings, the main use of its two-dimensional processing capacity.

(2)Tool paths can not be achieved with the three-dimensional model of the auto-correlation, When the product model a slight adjustment, will be spending a lot of duplication of work carried out the corresponding adjustments.

(3) There are more than 1000 sets CNC machine tools are in the company which all are made in Japan due to historical reasons. So the company has been unable to successfully promote the G code, which serious constrained the development of enterprises. Technology division is completed after the NC programming, and those codes have to manually enter the point coordinates for processing program, while making the technology could be the company straight to master a few senior engineers on the other hand. Also when manual input errors occur, even when in a complex surface, it will not be achieved through the manual programming. All of these have seriously constrained the rapid development of enterprises. Later the companies re-select EdgeCAM as CAM software (a machining tool path step of working simulation shows in fig 3), whose advantage of the following aspects to address the aspects of:

(1)As before receiving orders, customers generally require relatively straightforward to see products virtual machining process, The EdgeCAM is a leader in such software that can be a full realization of the geometric simulation of machining, the simulation process in addition contains the product model, the model also includes machine tools, fixtures model and tool models, more intuitive and realistic;

(2)Characteristics associated with the use of technology and product model automatically linkage, making use of the geometric processing of simulation model and design model of a high degree of consensus;

(3)The use of processing strategies technology, similar to features of the tactics employed for processing can greatly improve efficiency;

(4) By customizing the machine G code templates , making G-code can be generated directly to the machines to identify, and transfer to the machine.

IV. CONCLUSION Facing the challenge of E-Blocks, virtual manufacturing

enhances the competitiveness of the industry. With the establishment of virtual E-Blocks manufacturing integration framework.

TABLE I Efficiency Percentage

Name Before the

implementation of virtual manufacturing

(average days)

After the implementation

of virtual manufacturing (average days)

Improved efficiency percentage

Product Modeling 6 4 33%

Fixture Modeling 20 3 86.5%

Modeling Tool 20 12 25%

The Secondary development technology of CAD (computer aided design) is used to improve the efficiency of digital modeling. The trial period is cut down after the FEM (finite element method) is applied to the process of experimental cutting tool and structural modal simulation. The intelligence of virtual manufacturing is improved by using the technology of CAM (Computer Aided Manufacturing), which includes the strategy manager and the

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machining process simulation. The application shows that the trial period of E-Blocks of Computer Disk Drives is shorten nearly 50% by introducing virtual manufacturing (the Statistical results show in table I). The instance shows that the rapid development of virtual manufacturing technology provids a favorable channel for the E-Blocks.

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