With the rapid development of computer applications, the CAD/CAPP/CAM (hereinafter referred to as “3Câ€) technology of enterprises is becoming more and more mature, but each system is independent of each other, lacking effective information communication and coordination, forming an “information islandâ€. Information is difficult to share. These “islands†are not only reflected in information resources, but also in business processes. Enterprise 3C systems, PDM systems, etc. are usually established for different departments or business processes. They can only be used for specific enterprise workflows. Therefore, cross-system enterprise business processes are divided into different functions according to system functions. The business segment causes the business process to be “islandedâ€. With the gradual development of informatization construction, the integration between different information systems has become an urgent problem to be solved in enterprise information construction. The research of CAD, CAPP and CAM integration technology based on PDM platform provides a new solution for isolated information system integration. It enables seamless integration of 3C through a combination of hardware, software, standards and business processes.
1 Digital integration key technology
1.1 Product Data Management (PDM)
PDM (Product Data Management) is an information technology that optimizes the management of enterprise life cycle product data, resources and business processes. It is a technology platform for digital product manufacturing and is part of PLM (Product Lifecycle Management). It is based on product data and is an integrated environment and foundation for various other software tools and analysis and management tasks. It provides a structured way to efficiently, regularly access, integrate, manage, and control the flow of product data and data. Support technologies for PDM systems include large-capacity data storage, workload management, graphics conversion, distributed network environments, client/server computer architecture, friendly user interfaces, data management, and more. The architecture of PDM can be divided into four layers, as shown in Figure 1, which are the support layer, the object layer, the functional layer and the user interface layer.
The support layer is mainly used for general database management system, operating system, supporting environment of software and hardware, etc., providing the most basic functions for data management.
The object layer manages the product information in the data management layer in a structured manner to make up for the shortcomings of relational database management.
The function layer provides corresponding functional modules based on the management objectives of the PDM system on the basis of the object layer.
The interface layer provides an interactive human-machine interface that allows PDM users to easily manage product data and its processes.
1.2 Computer Aided Design (CAD)
The application of CAD (Computer Aided Design) technology has entered the stage of 3D digital design in the field of product design, and 3D digital design and manufacturing technology have been fully applied. Most manufacturing companies are based on the NX software platform. The 3D digital design technology is fully applied in the tooling design system to realize the full 3D digital design of the mold and complex fixtures, providing a unified data source for tooling manufacturing.
1.3 Computer Aided Process Design (CAPP)
CAPP (Computer Aided Process Planning) is a technology that uses computer technology to assist technicians in designing parts from blank to finished product. It is a technology that converts enterprise product design data into product manufacturing data. The application of CAPP system can not only improve the design efficiency and design quality of the process specification, shorten the technical preparation cycle, but also ensure the consistency and standardization of the process design, which is conducive to the promotion of process standardization. The CAPP system is developed twice, and the process file of the CAPP system is managed based on the PDM system.
1.4 Computer Aided Manufacturing (CAM)
CAM (Computer Aided Manufacturing) is the core of the computer integrated manufacturing system CIMS. The design result in CAD, after the CAPP process orchestration production process, finally generates and simulates the trajectory in the CAM, and generates the NC machining code to control the CNC machine tool for processing. It can be said that the benefits of CAD and CAPP are finally reflected by CAM. CAM can improve the product design and variety adaptability, improve processing speed and production automation level, shorten processing preparation time, reduce production cost, improve product quality and labor rate of mass production.
2 PDM-based 3C integration model and key technologies
2.1 3C integration mode under PDM platform
2.1.1 Package Mode
The PDM platform has a 3C encapsulation capability that provides a consistent model interface and logical independence for data and operations. Encapsulation has the function of switching from one application to another, and enables information sharing between different 3C systems. Similarly, in the 3C system, it can directly enter the PDM system and perform corresponding data management operations.
The encapsulation mode satisfies all data application requirements generated in file form. However, it is not possible to manage data inside 3C files, such as features, parameters, and assembly data. Therefore, the PDM system must apply the other two modes to such information.
2.1.2 Program Interface Mode
The 2D graphics software in the product design cannot generate an assembly tree, and the 3D solid modeling software can generate the assembly tree of the product, but it has nothing to do with the product structure tree in PDM. In order to realize the product structure tree in PDM is automatically generated by the assembly tree in the 3C system, and extract the latest product structure relationship from PDM, modify the 3C assembly file, maintain the data consistency between the two, through the preparation of the interface program, The standard data information interface is used to establish the connection between the product structure of PDM and various CAD software.
2.1.3 System Full Integration Mode
In this mode, PDM provides fully automatic exchange of bidirectional related information for various types of information, including product information, characteristic information, parameters, and application-oriented information, etc., and users work in a uniformly defined system environment. All PDM functions can be used on each 3C island technology system, and the 3C assembly relationship is always consistent with the PDM product structure.
2.2 Key technologies for 3C integration under PDM platform
2.2.1 Data information exchange technology
Integrated technology for product information exchange using dedicated data format files;
Integrated technology for product information exchange using standard data format files;
With the engineering database as the core, a unified product model is used to realize the information exchange integration technology.
2.2.2 Multi-database integration technology
In the 3C system based on PDM platform, the data characteristics are quite complex, both structured data information and a large amount of unstructured data; both data sources are heterogeneous and distributed in different places; and there are independent in each island system. The data source for the design. Information exchange and sharing between these data sources is required, while maintaining relative independence and local integrity. In order to implement system-wide data access services, a multi-database integrator (MDBI) is set up under the PDM integration platform. Multi-database integrator is the core part of multi-database integration system. It mainly supports the integration of off-site and heterogeneous databases, and realizes functions such as mode conversion, syntax conversion, semantic control, and distribution and control of data information in multi-database integration systems.
The multi-database integration technology includes four data structure modes: local mode, expressed by the original data model of the local database; output mode, each local database provides an output mode required for integration to the system, and describes the local database to participate in the global system. Local data information; integrated mode, organic integration of multiple output modes, describes the system integration relationship between local databases, and the mapping relationship between the output mode of each local database and its data operation commands; external mode, multi-database system Directly target specific user objects and their applications outside the system.
3 PDM-based integration implementation process
As a platform for 3C integration, PDM should provide data management and collaborative work environment for 3C systems, and also support the operation of 3C. The two-dimensional drawings, three-dimensional models, basic attributes of the parts, product schedules, assembly relationships between product parts, product data versions and status, etc. generated by the CAD system need to be managed by the PDM system, and the CAD system also needs Obtain information such as design task books, technical parameters, original parts drawings, data, and change requirements from the PDM system. In the CAD process modeling module, complete the design work of the part structure, add the attribute information and generate the design BOM, and generate a standardized data structure (such as generating a STEP file), and perform data conversion through the interface, and design in the form of a relational table. Information is stored in the PDM system.
Process information generated by the CAPP system, such as process routes, processes, work steps, fixture requirements, and modifications to the design, are managed by PDM, and CAPP also requires product model information, raw material information, and information from the PDM system. Device resource information. The integration of PDM and CAPP adopts the intermediate mode of interface integration and tight integration, that is, PDM is mainly based on interface development, and CAPP is mainly based on component packaging. For the PDM system, because the enterprise can not modify its source code, the integrated development can only use the interface function provided by it to develop the corresponding integration module; for the development of the CAPP system, the interface function is still used, or the CAPP system is used. Some functions are packaged into components for module calls after development by the PDM system. Other systems use the PDM platform to extract process design information and process documentation information. The integration scheme of CAPP system and PDM system is shown in Figure 2.
CAM transfers the tooling file (Cuting Location) and NC code (CNC code) generated by PDM to PDM, and obtains product model information and process information from the PDM system. 3C integration requires that the NC machining program is generated based on the CAPP process equipment results and CAD part information, automatically generates the tool path file with the standard format, and then converts the tool path file into NC machining after proper post processing. The program generates a CNC machining code for a specific machine and stores the output results in a PDM system. The integration framework is shown in Figure 3.
In the CAM module, the information provided by CAD and CAPP is extracted from the PDM system, and the extracted process information is automatically input into the processing module of Pro/NC through the various interface functions of Pro/NC, and the assembly module in Pro/NC is installed. On the basis of establishing the processing equipment model, the blank model, the fixture model and the tool model, the virtual machining environment is constructed, the machining process simulation is automatically completed, the collision interference during the machining process is checked, and the modification opinions are proposed. After the simulation of the machining process is correct, the tool path file is output, and the machine name of each process is read in the network database, and the tool path file is converted into an NC code suitable for the machine tool by using the configuration file for the machine tool.
4 Enterprise implementation of integration effects based on PDM system
4.1 Realize BOM data management and transmission
The BOM (Bill Of Material) is called a product structure list and can also be called a product structure tree. The BOM (EBOM), the process BOM (PBOM), and the manufacturing BOM (MBOM) are respectively corresponding in 3C. The design BOM is to explain the composition of the product from the perspective of product design; the process BOM is the product product process after the process planning, including machining, stamping, welding, assembly and other processes; and the manufacturing BOM is the description of the product data in the production process. . In general, the structural relationship of manufacturing BOM is consistent with the process BOM, but manufacturing BOM sometimes contains a lot of other information related to the manufacturing process. The integration process of 3C is also the transfer process of BOM data in 3C system, and also the data release process from design BOM to process BOM, process BOM to manufacturing BOM.
4.2 Implementing a paperless process management system
The PDM system coordinates and controls the process of generating, modifying, and using product data according to the management rules formulated by the enterprise, so that the review process of the technical documents is automatically and orderly, and reduces the number of modifications and repetitions in the design process. The accuracy of the design and manufacturing process has greatly shortened the product development cycle and produced huge economic benefits.
4.3 Realizing 100% Process Management
From process planning, part process design to product process, including a large number of iterations, changes, modifications, replacements, etc., PDM systems can centrally manage all of the above process documents, ensuring the integrity, correctness and uniqueness of process information. Sex.
4.4 Implementing Single Data Source Management
The version management capabilities provided by the PDM system ensure that all employees participating in the same project work with a single data and are up-to-date and up-to-date, ensuring consistent process data and reducing duplication and changes in the design.
4.5 Realizing Tooling Resource Library Management
PDM-based tooling resource management supports the current networked, distributed, and virtualized organizational model of the enterprise. The system has process management, design, change, summary, and other data management and tooling application, design, modification, and distribution process management. The networked management of the resource library enables information such as tooling design, production, and inventory to be shared, improving the efficiency of tooling.
4.6 Realize the 3D design of components
In the product design stage, digital technology is used to build a full three-dimensional digital model of product components, virtual assembly of components or machines, motion mechanism simulation, pipeline design, aerodynamics and strength analysis. In the product manufacturing stage, the three-dimensional digital model of the product provided by the upstream design institute can be directly used for process specification preparation, tooling design, CNC machining programming, machining process simulation, and three-coordinate measurement to reduce manufacturing rework risk, reduce manufacturing cost, and improve engine quality. Shorten the product development cycle.
4.7 Realize concurrent engineering and shorten product development cycle
Techniques that make product design highly predictable and preventive are called "parallel engineering" or "parallel design." By integrating all the resources of the enterprise, the concurrent project enables product developers to consider all the factors in the product life cycle (including design, analysis, manufacturing, assembly, inspection, maintenance, cost and quality) as early as possible to improve product quality and reduce costs. Shorten the development cycle. Its essence is a systematic approach to designing products and their components and related processes in an integrated and parallel manner. The parallel process can greatly shorten product development and production preparation time, reduce costs, improve quality, and ensure product reliability and practicality.
4.8 Facilitate the implementation of total quality management
By introducing a set of relevant review processes within the product development cycle, the PDM system can establish an environment that is compliant with IS09000 series verification and total quality management.
5 Development direction of off-site digital design/manufacturing/management integration for product life cycle
Aeroengine development has always adopted the traditional mode based on drawings. With the rapid development of computer software, hardware technology and integration technology, the development of a large number of new product models has introduced digital manufacturing technology combining two-dimensional and three-dimensional. However, no matter which development mode, the product manufacturing basis is still the traditional two-dimensional engineering drawings, the design intention is difficult to understand, the information transmission is not timely, and the cost is high; and the three-dimensional digital model containing only geometric information is in product design, process design, tooling. The application results in the design, numerical control programming, product manufacturing and numerical control testing are not satisfactory. The performance is inconsistent data transmission and large repetitive workload, which is not conducive to improving product quality, reducing processing cost and shortening product manufacturing cycle. Therefore, MBD (Model Based Definition) Technology came into being. MBD technology fully expresses product information through an integrated 3D solid model, specifying the dimensions, tolerances and process information of the products in the 3D solid model. Full implementation of MBD-based digital design and manufacturing technology will become an effective way for aerospace manufacturers to improve overall product manufacturing levels, shorten manufacturing cycles, reduce manufacturing costs, improve product quality, and change traditional methods of development.
After the full three-dimensional process design and application of MBD technology, enterprises need to gradually establish resource libraries of standard parts, machining tools, cutting parameters, equipment, tooling, etc., explore advanced digital manufacturing, digital detection and processing simulation technology, and realize the parallel design of process tooling. In order to maximize the technical advantages of MBD in the manufacturing process. With the further strengthening of MBD technology, enterprises' integrated application manufacturing technology will have more room for development.
6 Conclusion
As an integrated working platform of 3C, PDM provides an environment for data management and collaborative work for 3C systems. It can span multiple operating platforms and application software platforms to achieve multi-platform information integration. The application and research of integration technology based on PDM platform has promoted the rapid realization of informationization by enterprises, laying a solid foundation for the early realization of collaborative production in different places.
Product introduction
Type CH4 Adsorbent
Coal bed methane (CBM) is a kind of clean energy with high calorific value and no pollution.
Its main component is methane, which is very rich in resources.
In order to ensure the safety of coal mining, coal bed methane extracted from the mine is mixed with a large amount of air, resulting in 20% to 40% low concentration of coal bed methane, and containing less than 18% oxygen, causing safety hazards for methane concentration, and removing more than 60% nitrogen, which increases considerable difficulty for adsorbent.
By using this adsorption, the mixture of CH4 and N2 from 30% to 70% can be enriched to over 92% with a recovery rate of more than 31.6%, and the mixture of CH4 and N2 from 50% to over 95% with a recovery rate of more than 47%.
CMSCH4 concentration CBM methane adsorbent has the following characteristics:
Effective purification of methane content of coalbed methane is more than 5% (extremely high methane content, obvious effect).
2. It has very strong deoxygenation and explosion-proof functions to ensure the safety of PSA in the process of coal bed gas enrichment;
3. Adsorption at room temperature and low pressure, low energy consumption;
4 radix can be deoxygenated at the same time of CH4 and N2 separation without prior deoxygenation or methane enrichment, with obvious low cost and economic benefit.
Technical indicators:
A, appearance: ï¿ 1.3 mm x 2 -- 4 mm columnar grains
B. Adsorption pressure of ife: 0.2mpa (table pressure)
Specific gravity of c treatment: 0.65g/ml -- 0.65g/ml
Methane concentration in d phase product: greater than or equal to 90%
E phase intensity: 95% or more
Methane yield of f-process products: 40% or more
Output: CH4 products
CH4 purity: 80~99% (V), produced according to different USES and requirements of users.
CH4 yield: 70~95%
Ventilation P: 0.05~ 0.1mpa
Output temperature: normal temperature
Note: the yield of CH4 is related to raw material composition, pressure, product and product H2 purity.
Type CH4 Adsorbent
Type CH4 Adsorbent,Pressure Swing Adsorption,Tuning The Adsorption Properties,Methane Absorbent Oxygen
Zhejiang Changxing Haihua Chemical Co.,Ltd. , https://www.zjcxhhcms.com