Views:1560 Author:Site Editor Publish Time: 2019-04-09 Origin:Site
Machining is widely used in our life, we need machining to manufacture mode so that we can get the ideal finished products. Machining can be divided into two groups, one is conventional machining, the other one is non-conventional machining, the most common one of non-conventional machining is CNC (Computer Numerical Control) machining. Today, this article will separately introduce conventional machining and CNC machining to you, also, we will compare these two method for you to make a reasonable choice.
List: 1. Introduction of Conventional Machining
2. Introduction of CNC Machining
3. Comparisons between CNC Machining and Conventional Machining
Machining is the process of cutting a piece of raw material into the required final shape and size through controlled material removal process. Conventional machining uses tools such as lathes, milling machines, boring machines, drilling machines, etc., and uses sharp cutting tools to remove materials to achieve the desired geometry. Usually there is direct contact between tools and raw materials. In traditional processing, materials are removed by direct contact between tools and workpieces. Energy is used to rotate workpieces or tools. Cutting tools should be harder than workpieces (hardness increased by 35-50%).
In the abbreviation of "Computer Numerical Control", CNC process is contrary to the limitation of - and thus replaces - manual control. Manual control requires field operators to prompt and direct the commands of processing tools through levers, buttons and wheels. For bystanders, CNC systems may resemble a set of conventional computer components, but the software programs and consoles used in CNC processing distinguish them from all other forms of computation. CNC machining is a manufacturing process, in which the pre-programmed computer software determines the movement of tools and machinery in the factory. This process can be used to control a series of complex machinery, from grinders and lathes to grinders and routers. Through CNC processing, the three-dimensional cutting task can be completed in a set of prompts. Generally CNC processing usually refers to precise machining controlled by computer digitally, CNC processing lathe, CNC processing milling machine, CNC processing boring and milling machine, etc. CNC, also known as computer gongs, CNCCH or CNC machine tools, is actually a name on the other side of Hong Kong. Later, it was introduced into the Pearl River Delta of the mainland. In fact, it is a CNC milling machine. In Guangzhou, Jiangsu, Zhejiang and Shanghai, CNC machining center is a new type of processing technology. Its main task is to compile processing programs, which will turn the original manual work into computer programming. Of course, there is a need for manual processing experience.
1. Processing Technology of CNC&Conventional Machining
In conventional machining technology, both positioning datum, clamping method, cutting tool and cutting method can be simplified, but data processing technology is more complex, these factors need to be fully considered, and even if the same processing task, CNC processing technology can have multiple schemes, which can work on multiple parts and cutting tools as the main line. The arrangement of technology and the diversification of technology are the most definite differences between CNC and traditional machining technology.
2. Thermal Deformation of CNC&Conventional Machining
Whether in the conventional machining process or the CNC machining process, there is inevitably thermal deformation during cutting. In the finishing stage, the thermal deformation directly affects the accuracy of the final workpiece. In the traditional machining process, due to the long buffer time between the various processes, the processing stages can be clearly divided. Therefore, at the beginning of the finishing stage, the temperature rise after the previous processing can be completed and restored. Further, it can be further divided into several steps in the finishing stage, which can effectively reduce the adverse effects caused by thermal deformation. However, the numerical control machining process is a continuous addition of multiple faces, and it is highly efficient, which results in no heat transfer during the cutting process. Therefore, thermal deformation is a prominent problem in the numerical control machining process. At present, in the machining process of CNC machine tools, the cutting fluid is usually used to achieve the function of cooling and chip breaking, so as to ensure trouble-free production.
3. Clamps and Fixtures of CNC&Conventional Machining
In CNC machining process, not only the coordinate direction of fixture and machine tool should be relatively fixed, but also the dimension relationship between parts and machine tool coordinate system should be coordinated. In addition, the two steps of positioning and clamping need to be effectively controlled in the clamping process. Moreover, under the traditional machining technology, because of the limited processing capacity of the machine tool itself, it is necessary to clamp several times in the process of processing. Moreover, special fixture is needed, which leads to higher cost in design and manufacture of fixture, and invisibly increases the cost of product generation. In most cases, there is no need for special fixture design, so its cost is relatively low.
4. Processing Mode of CNC&Conventional Machining
In the traditional machining process, some processing processes can not be used easily because they can not be accurately controlled. However, when using CNC machine tools for processing, these prudent additive methods become feasible. In the process of CNC machining, filling method, empty cutter method and dressing method used in traditional hole position processing have been replaced by circular solitary interpolation, back building method and CNC dressing method. Hard cutting technology has also been applied in processing, which not only effectively ensures the improvement of processing efficiency, but also reduces the processing cost to a large extent, and reduces the investment of equipment. At the same time, compared with wet cutting method, dry cutting can be said to be a green manufacturing process, which has obvious advantages in cutting, but because of its large cutting force, there are problems of large deformation and tool wear in the cutting process.
5. Tool of CNC&Conventional Machining
In the process of machining, the choice of cutting tools needs to be determined according to the different processing technology and methods. Especially in CNC machining, the use of high-speed cutting is not only conducive to the improvement of processing efficiency, but also can ensure the quality of processing, effectively reduce the probability of cutting deformation, shorten the processing cycle, so the demand for cutting tools under high-speed cutting is further increased. At present, there is also a dry cutting method, which cuts without cutting fluid or only a small amount of cutting fluid, so the cutter is required to have good heat resistance. Compared with ordinary machining technology, CNC machining technology has higher requirements on the performance of cutting tools. As the current numerical control processing technology has become the main technology in the modern processing industry, it has also led to great changes in the tool industry. It is no longer just for the production and supply of tools, but has begun to change to the development of new cutting technology and related supporting technologies. Tool manufacturers have also become an important cooperation in improving production efficiency and quality and reducing production costs in the current processing industry.
6. Cutting Parameters of CNC&Conventional Machining
In the conventional machining process, in the process of operating the machine tool, the workers often rely on their own practical experience and technical experience to operate, from the perspective of human control and safety, generally conservative, especially Complex curves and surfaces, worker operations are prone to errors, and in order to reduce scrap rate, the choice of cutting amount is always cautious. The CNC machine tool uses the control system to control the machine tool movement. The machining process can be easily controlled by the program regardless of the shape. The movement path of the tool on the workpiece is fully automatic and flexible, and it can be set in the program. Reasonable cutting amount will not waste material and unnecessary loss, and maximize the processing efficiency, which is unmatched by ordinary machine tools.
Above all, it is easy to distinguish between conventional machining and CNC machining. CNC machining is more convenient to use in manufacturing and it requires higher technology, however it has higher efficiency, so more people will prefer CNC machining.