Machine tool spindle is the core part of the machine tool, its function is to drive the tool (grinding wheel) or workpiece rotation to achieve processing. The quality of the spindle of the Machine tool will directly affect the surface quality, processing accuracy and production efficiency of the machined parts of the machine tool. Therefore, we want to improve the processing performance of the machine tool, and then improve the processing quality, processing accuracy and production efficiency of the machine tool, in order to enable the machine tool to process better quality products, to meet our growing production and life needs, Then, whether the process flow of CNC lathe machining machine tool spindle is reasonable or not has an important impact on the accuracy and quality of the machine tool. This paper analyzes and summarizes several important steps in the processing of CNC lathe, and takes CNC lathe machining spindle parts of super precision machine tool as an example to optimize the process through a large number of actual processing and research analysis. The defects and improvement measures in the process are put forward, and the reasons for affecting the machining precision and quality are found out, so as to improve production efficiency and create economic benefits for enterprises.

The performance of the machine tool spindle must meet the processing accuracy and efficiency as the premise, some traditional spindle concept can not meet the needs of the current machine tool spindle, its speed and accuracy, as well as stiffness, power matching characteristics are better, so we must consider the quality. When Automatic CNC Machine machining parts, the turning parameters and cutting path are set and then turned through the computer control system, so the important factor affecting the processing quality and efficiency of the parts is the processing process flow of the CNC lathe. With the development of numerical control technology, the processing quality is improving, but there is still a lack of guidance in the technical standardization of numerical control processing, so that the consistency and stability of product quality can not be guaranteed, this factor to a certain extent, there are constraints on the technical development of numerical control lathes. The following from the CNC lathe processing processing method and process selection, line development, tool installation, and other important steps to the parts of the effective change of the process of the way to analyze:

First, the manufacturability analysis of the machined parts should be accurate

1, the need to process the parts of the process to meet the characteristics of several car processing

In the design of the drawings of lathe machining parts, the size of the mark should be based on the premise of convenient processing, and the drawing should directly use a unified benchmark and give the coordinate size, so that it is easy to program and coordinate the various sizes, and ensure the consistency of the process benchmark and the design benchmark, so that the detection benchmark and the programming origin provide convenience. In this way, designers have eliminated concerns about the use of product characteristics, in manual programming to calculate the base point coordinates and calculation points, should pay attention to whether the workpiece contour geometric elements of the conditions, automatic programming to all geometric elements defined in the process analysis to fully consider the sufficient and reasonable characteristics of each geometric element.

2, the parts to be processed are suitable for the characteristics of CNC lathe processing

First of all, pay attention to the shape of the parts and the inner hole need to use a uniform size and geometric type of tool as far as possible, and minimize the number of tool replacement. The quality of the machined parts is related to its contour shape and arc radius. Therefore, the fillet in the slot can not be too small, because there may be no corresponding tool to match, to prevent the side stress concentration caused by bad structure of the part, so that the life of the part is affected, in order to prevent the workpiece repeated clamping to form the size of the two faces of the processing and the position of the contour asymmetry, we try to unify the positioning basis in the arrangement of the process. The corresponding reference hole can be used as a process hole, and the workpiece should also have a positioning reference hole. The above two ways can not be achieved, the unified positioning standard can also be considered with a finished surface, and the error of two clamping can be reduced.

Second, the use of processing methods and processing procedures should be appropriate

1, choose the appropriate processing method

The suitable processing method in the processing is to ensure that the processing accuracy and the surface roughness of the workpiece can meet the design requirements and standards for the principle. When selecting the processing method, it is necessary to consider the shape, size and technical requirements of the parts and heat treatment, and select the suitable processing method in the processing method that can reach the same level. According to the actual situation of the production equipment, for some holes on the surface of the box select reaming method, the larger hole on the surface of the box is generally boring, the smaller hole is generally reaming method, and we should also consider reducing production costs and improving production efficiency as much as possible according to the actual situation in processing.

2, choose the appropriate processing process

In CNC lathe processing, it is considered whether all the processes or most of the processes can be completed in one time when clamping, and the process is concentrated as much as possible, which requires first to analyze whether the processing of the entire part in the pattern can be completed in one time, if not achieved, to reduce the number of clamping and the number of tool replacement. And in the division of the work step, the processing accuracy and processing efficiency of the two factors should be considered, in the same workpiece processing surface sequence is rough machining, semi-finishing, finishing, can also be all surface rough machining, finishing.

Third, develop optimal processing routes

The principle of formulating the processing route should be followed: reduce the idle time of the tool and ensure that the processing route is short, and the ineffective program segment should be reduced; Ensure the surface accuracy and surface roughness of the parts; In order to reduce the programming workload to simplify the numerical calculation; In CNC lathes, some point control only requires higher positioning accuracy, and the cutting tool route is not very important, so a lathe like this is a line with a short empty stroke, and the distance of the tool in the direction of the shaft should be determined, and this factor is affected by the length of the workpiece stroke.

Four, the development of CNC lathe tool installation design and process card

1, tool installation design

The basic criteria we should consider when installing the tool are: try to unify the process and set the benchmark for the steps to be programmed; The number of times in the clamping is less likely, and it can be completed by clamping at one time when all the processed surfaces are processed; In order to give full play to the effectiveness of the CNC lathe, to avoid the purpose of manual adjustment. In the processing of CNC lathes, it should also be noted that when the number of parts processed is not very many, the basic requirements for the fixture in CNC machining are put forward: first, the coordinate direction and the coordinate direction of the fixture should be guaranteed to be fixed relative to each other; In addition, we should also pay attention to the relationship between the size of the coordinate system of the machine tool and the parts. Thus to save production costs and save some production preparation time.

2, about the development of CNC lathe process card

CNC lathes because the price is relatively high and its performance is very good, because of the characteristics of CNC lathes, the process content is also complex, so it can complete complex work tasks. The problem of improving the work step on the CNC lathe programming is the factor of raising the rate, so consider the main content of the CNC machining process, the route, the tool point, the tool change point and the origin, turning parameters, programming instructions, etc.

3. About the effect of the improved shaft

We improved the CNC turning process of the machine tool spindle, and found that after the optimization of the turning process, through the surface roughness and dimensional accuracy of 100 finished parts were tested and analyzed, the results were that all the dimensional tolerances were controlled within the tolerance range, and the product quality was very good. Moreover, in the detection of runout tolerance and coaxial tolerance, it is controlled within the qualified range of 0.01m m and φ0.005m, respectively. In order to meet the requirements of subsequent processes, the roughness of the end face and the outer circle meet the requirements of the drawings respectively. The length size is controlled within the tolerance range, the requirements of the enterprise can be fully met, and the production efficiency has been greatly improved, from the original 50min a piece to the current 35min a piece.

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