1 Introduction    The forming turning tool is a special tool for machining the forming surface of rotary bodies commonly used in cutting processing, and the shape of the cutting edge is designed according to the surface profile of the rotary body to be machined. The use of a turning tool not only ensures stable machining quality, but also has high productivity, more re-grinding times and longer service life. However, the traditional manual design method of the shaping tool has a long design cycle, heavy workload, and low design accuracy. In order to shorten the design cycle and improve the design accuracy, we have developed a computer-aided design system for prismatic turning tools. 2 System Configuration and Operating Environment figure 1 The prismatic turning tool CAD system uses AutoCAD R2000 as the supporting platform, and uses the Object ARX 3.0 secondary development tools provided by Visual C++ 6.0 and AutoCAD R2000 to compile the application program into an ARX dynamic link library, and loads and runs in the AutoCAD environment. The system interface adopts Chinese interactive operation, and each step has its own prompt. The system adopts a modular structure design and consists of function modules such as initialization settings, tool structure design, profile design, graphic generation and dimensioning, and graphic output (see Figure 1). 3 CAD design method for prismatic turning tool The front and rear corners of the forming tool are formed by mounting. During design, after the system prompts the user to select the workpiece material, the system can automatically determine the front angle gf and the back angle af of the shaping turning tool according to the selected material. 1. Design of tool structure The dovetail structure is used for the clamping part of the prismatic turning tool. This structure is reliable and can withstand large cutting forces. The main structural parameters of the prismatic turning tool include the total body width Lc, the height H of the body, the thickness B of the body, and the size of the dovetail structure. a. The total body width Lc The total body width Lc of the turning tool is equal to the total cutting edge width Lc, ie, Lc=l+a+b+c+d. The meaning of each dimension in the formula is shown in Figure 2. l is the profile width of the workpiece; a is the width of the additional cutting edge to avoid overcut at the corner of the cutting edge, take a = 0.5 ~ 3mm; b is the additional cutting edge width considering the workpiece face machining and chamfering, its value should be greater than Finishing allowance and chamfer width. If the workpiece has a chamfer, then the Kr value in this segment should be equal to the chamfer value, and the b value should be 1 to 1.5 mm larger than the chamfer width. The system needs to determine whether the rightmost surface of the workpiece is a circular arc or a chamfered portion based on this value. c. The width of the cutting edge of the pre-cut groove, which is to ensure the smooth execution of the subsequent cutting step, is taken as c=3~8mm; d is the additional cutting edge width required to ensure that the cutting edge exceeds the surface of the workpiece blank, and d=0.5~2mm. The above parameters are in the common range (in mm) of the prompt on the command line and are entered by the user in AutoCAD commands. figure 2 b. body height H In the case that the shaping tool holder and tool holder structure allows, the height H of the tool body should be made as large as possible, which can increase the number of re-grinding of the tool. The recommended value for this system is H=75~100mm and the tolerance is ±2mm. This parameter can be input through human-computer interaction. c. body thickness B The thickness of the blade body B should be selected to ensure that the blade body has sufficient strength. At the same time, factors such as smooth chip removal and easy installation should also be considered. In addition, the B value is also related to the size of the dovetail structure and the maximum profile depth Amax of the workpiece and should meet certain conditions. The B value is automatically selected by the system based on the total tool width. d. Dovetail structure size The size of the dovetail structure should be compatible with the total cutting edge width Lc and the structural dimensions of the turning tool, as well as the size of the clamping structure. Since the dovetail dimensions have been standardized, the system has stored the dimensions of the dovetail structure in the relevant literature in a data file for use by the system. The system can automatically select the size of the dovetail structure based on the total tool width. 2. The design of the tool profile Rotary body parts generally consist of arc segments, straight segments, and other non-circular curve segments. Since the calculation methods for the correction of each segment shape are different, the arc segment and the straight segment must be distinguished before performing the profile correction calculation. The system performs data processing and profile calculation according to the diameters of the turning points input by the user in human-computer interaction mode and the corresponding upper and lower deviations and axial distances, and performs coordinate point setting according to a predetermined drawing direction. In performing the correction calculation on the arc segment, it is necessary to determine whether the arc is a convex arc or a concave arc, a symmetrical arc, or an asymmetric arc. When the workpiece forming surface is a circular arc, due to the existence of the rake angle and the relief angle, the corresponding shaping profile of the turning tool is not actually an arc shape. However, when the accuracy of the arc shape is not high enough, for the sake of simplicity, the arc can be used as a tool profile, but its radius will increase, as shown in FIG. 3 . In the figure, 1-2-3 shows the arc of the workpiece with radius r, center at point O, and profile depth ap. The calculation method can be used to calculate the depth P of the profile of the tool and the point 2', and then use 1 , 2', 3 as an arc, which is an approximate arc that can replace the tool profile curve, its radius R and center The position of the point OC can be determined from ΔOA3 and ΔOCA3. 3. Graph generation and dimensioning a. Graph generation Based on the data obtained in the above design steps, the system defines the coordinates of the point and determines the direction of the minimum radial point on the workpiece by converting the profile points and the dimensions of the forming tool work diagram and the template diagram, thereby determining the point Coordinates and drawing direction. By calling AutoCAD commands, you can generate work drawings and template drawings of a turning tool. b. Dimensioning The dimensions of the prismatic turning tool can be divided into shape size and position size. When automatically dimensioning dimensions, attention should be paid to problems such as repeated dimensioning of dimensions, missing labels, and mutual interference between relative positions. The profile of the forming tool profile is exactly the same as that of the shaping tool profile (including the additional cutting edge), and the dimensioning reference should be the dimension reference of the tool profile. The system has designed the corresponding sub-functions, which can sort and automatically dimension the dimensions, and can save the dimensioned work and model diagrams in the form of blocks (BLOCK) to prepare them for recall. image 3 4. The output of the graph a. Frame settings The system can automatically select the frame size according to the size of the turning tool (you can also choose the size of the frame by the user), and call the INSERT command to insert the generated work pattern and template image block into a suitable position according to a certain proportion. b. title bar filling and technical requirements labeling The system uses the Dialog Control Language (DCL) language to develop a title bar and technical requirements input dialog. Fill in the dialog box, such as the designer's name, material, proportion and other information, the system can automatically fill it into the corresponding position in the title bar, as shown in Figure 4. 4 Conclusion Figure 4 The computer-aided design system of prismatic turning tool adopts Visual C++ 6.0 to carry out secondary development of AutoCAD R2000. Users only need to enter the necessary design data in human-computer interaction to design a prismatic turning tool that meets the requirements and outputs engineering drawings that meet the requirements of the national standard. The application of this system can significantly improve the design accuracy and efficiency, shorten the design cycle and reduce the design cost. At the same time, the output data can be easily converted into numerical control processing instructions. Therefore, it has good practicality and promotion value. Misting Fan,Cool Mist Fan,Portable Misting Fan,Oscillating Misting Fan Foshan kanasi electrical co.,ltd , https://www.kanasifan.com
