Analysis on the Ways and Measures of High-efficiency NC Machining of Mould

As an advanced manufacturing technology introduced for many years, CNC technology has a high technical content and involves many aspects, including rapid and efficient CNC machining programming, multi-axis simultaneous machining of space free-form surfaces, cutting of difficult-to-machine materials, and application of high-speed cutting. Standardization and standardization of CNC process programming. The efficiency of CNC machining is largely related to the company's own technology governance model, especially in the early stage, how to overcome a new and difficult technical application difficulty in a short period of time, so that it can better play its efficiency. The main topics that companies must pay attention to.
The informatization construction of process technology has some defects in the governance of domestic enterprise process technology. The enterprise has not adopted an effective governance mode according to its own strength and development strategy. The backwardness of information technology governance of process technology is mainly manifested in the insufficient sharing of information technology resources in product design and manufacturing process, the compilation of CNC process programming and management, the poor combination of CNC process and common process, the uneven application level of CaD/CaM software, and CNC machining. The standardization and standardization of processes and procedures are low, and product design, numerical control technology, and parallel programming of numerical control programming are small. In view of the information construction and governance requirements of the manufacturing process, the informatization construction of the process can be carried out from the following aspects.
1. Product design, process information resources sharing The most important aspect of information technology construction is to make full use of product design graphics and document resources, and make full use of the successful manufacturing process experience of enterprise products, such as using CNC 3D graphics to reduce CNC programming. The three-dimensional modeling time of the staff, while the three-dimensional modeling almost consumes 50% of the time of numerical control programming. Establishing tool information base, cutting parameter database of difficult material, clamping positioning information, processing technology and program template of typical materials and parts, and expert database can help improve the quality and efficiency of programming, and make full use of PDM and network resources to establish development. An internal process information management system that shares all possible manufacturing information resources.
2. The combination of CNC machining and traditional machining The NC process is connected with the common process. The most important thing is to take different measures for the different design features, batch requirements, production cycle, machining accuracy and production cost. In the process design process, the design status of the product, the processing method, the design and manufacture of the tooling fixture, the selection of the tool, the combination of the roughing and finishing methods, the centralized division of the process, the status and capabilities of the equipment of the enterprise should be considered comprehensively. In practical applications, it is also necessary to combine the enterprise equipment capabilities, the technical workers and the technical staff's water equivalent factors. Aiming at the processing characteristics of the developed products and batch products, the development process and batch production process countermeasures suitable for their respective requirements are adopted to achieve the perfect combination of CNC machining and traditional machining.
3. Parallel programming of CNC process and programming In the early stage of the process, NC programming participation becomes passive and active, which can greatly reduce this type of error or risk. CNC machining can only fully discover the problems in the process and the program during the process of three-dimensional modeling of the product and the preparation of the NC program. This is because the CNC process and the programmed program must ensure that the qualified products can be completely processed. Unlike the ordinary process, as long as there is no problem overall, the size is not missed, and whether the part can be fully processed depends on the experience and level of the skilled worker. The realization of the parallel mode of the NC process program can be realized from the sharing of the three-dimensional CaD model of the design product, the single-person responsibility system of the numerical control process program, the participation of the numerical control technicians in the preparation of the NC program, and the special responsibility system of the NC machining process and the program.
4. The standardization of NC machining program programming standardizes the level of application of CNC machining technology to a certain extent. It regulates the diversification of NC program through standardization, and then improves the quality of tool path, such as in the process. Indicate the positioning reference, tool setting reference, coordinate system, tool parameters and cutting parameters. Standardized programming can be performed from two-dimensional contour machining, three-dimensional surface machining, fixed cycle and subroutine use, tool compensation, and tool path roughing strategy. On the basis of the processing experience of typical parts, the establishment of standardized machining process templates and numerical control program templates can greatly improve the quality of the process and the processing efficiency of the products.
5. Database management of numerical control process program The NC program of different types of product parts, fixtures and molds is based on the contents of the process steps, numerical control equipment, tools, program list, etc., based on the centralized management of the database system, avoiding the traditional folder form The defects of governance are convenient for the secondary use, query, editing and modification of the program, and can save the program management and search time of the numerical control staff, avoid the wrong use of the program, prevent the loss of the program or the repeated compilation of the NC program of the same product.
6.Vericut machine tool simulation software application For five-axis machining and large changes in machining volume, Vericut software can be used to avoid collision collision and other optimized tool path.
Progressive application level of CaD/CaM software
The application level of CaD/CaM software is one of the factors in the application level of CNC machining technology. In the NC programming, a reasonable modeling programming mode should be adopted according to the characteristics of the product.
1. The combination of manual and CaM programming makes full use of the programming modules provided by the relevant CNC machine system itself, such as CNC milling for rectangular grooves, U-shaped grooves, drilling cycles, CNC turning end faces, external circle machining, EDM machines. Electrode shaking processing function, expert selection of discharge process parameters for wire cutting processing, etc., can greatly improve the efficiency and correctness of numerical control programming.
2. Choosing a fair CaM programming strategy When establishing a product processing model, effective and simple measures should be taken for the specific characteristics of the product processing object. According to the programming of the product parts, the content of the process is relatively simple, and the interference is less. For example, the holes, the grooves, the bosses and the like are often found in the programming and processing of the structural parts. The overall modeling of the product processing model is mostly used for the processing of features such as more processing, multi-interference areas, and complex curved surfaces.
3. Use of NC programming templates Using the CaM system to create your own templates and reuse them can greatly improve programming efficiency. For example, when manufacturing a mold, the best process for machining the punch and the die is defined as a machining template. When processing a new similar product object, simply call the template file to select the desired geometry and start the process. The Machining Wizard makes it easy to get expert-level manufacturing process guidance from the template and quickly and automatically CNC tool path through simple interaction.
4. The application of CaD/CaM expert system utilizes the functional modules of CaD/CaM software, such as sheet metal design, mold design, related design, part family design, user-defined design and other expert design knowledge, which helps to reduce the three-dimensional modeling of products. Time, thus improving the efficiency and correctness of CNC programming.
5. Development companies with dedicated post-processing programs generally have the diversity of numerical control systems, such as FaNUC, SIMENSE, HEIDENHaNE, etc. Each CNC system has its own advantages but is incompatible with each other, and it is difficult to achieve the same. Develop the post-processing program of the existing CNC machine tool system. It can be specialized in the software configuration and program output format, coordinate transformation, etc. from the technical engineer with software development and CNC machining experience. The development ensures that when the same type of machine is being machined, the program code of the corresponding CNC machine can be output while sharing the same tool path.
6. Designing a fair tool path NC machining is ultimately reflected in the fast, high-quality design of the tool path, especially in the case of large mold blanks. The conventional method generally uses an end mill for roughing, and a ball-end cutter for semi-finishing and finishing. In the roughing process, it is necessary to make efficient and rapid displacement, and make full use of the combination of ordinary equipment and numerical control equipment. In the finishing process, the level of the enterprise mold fitter should be considered. The fairness of the tool and the step size, the tool and the step size are too large or too small, which is not conducive to the processing efficiency and manufacturing cost of the product. The NC programming should combine the materials and machining allowances to scientifically consider the cutting parameters of the machining, and aim at equal volume variable cutting and high-speed cutting, and establish a cutting process parameter library for developing common material tools.
CNC equipment selection and function development The purchase and use of CNC equipment largely determines the potential of the equipment. Many companies have some problems in terms of equipment selection and purchase, such as equipment travel, accuracy, function, and potential for development. In particular, CNC equipment is developing in the direction of high speed and precision. When purchasing high-speed machine tools, we must consider the integration of capital, CaM software, experience and application level. For the shifting or gravity cutting of traditional difficult-to-machine materials, it is necessary to consider the rigidity of the spindle shank. Try to use a large model, such as the BT50 milling shank, and consider the expansion of the machine function. On the other hand, in the development of the function and potential of the device itself, machine tool accessories, such as the application of angle milling heads, to expand the scope of application of the machine tool. For the selection of numerical control equipment and the development and use of machine functions, some necessary work can be carried out from the following aspects.
1. The combination of high-end and low-end numerical control equipment Because the price of numerical control equipment is relatively expensive, enterprises can use the modified numerical control equipment to invest in technology application according to their own actual situation, and obtain certain application experience. According to the processing characteristics of the product, such as material status, type, precision, batch, cycle requirements, etc., configure appropriate medium and high-end CNC equipment.
2. Acceptance of equipment Many CNC machine tools have large errors in the compensation accuracy in the case of high-speed machining, or it is difficult to run the spindle at a high speed for a long time, resulting in the phenomenon that the spindle is burnt due to high temperature. In the acceptance of equipment, in addition to the national acceptance criteria, the acceptance conditions of the company's own product processing requirements can be added.
3. Equipment function development The development of equipment functions involves the degree of control of the numerical control system, and the fair matching of the tool and workpiece materials with the cutting parameters. For example, the vertical CNC milling machine is equipped with an angle milling head for horizontal machining, a CNC milling machine for boring and tapping, a fixed cycle for CNC turning, and a fair selection of electrical machining parameters for CNC wire cutting machines and EDM machines.