Use the tool with diameter d = 30mm and bottom corner radius r = 2mm for semi rough machining, create the program as face milling, select several open plane areas such as riser item plane, bottom plate large plane and sand core 2 upper plane, and select the reciprocating mode as the cutting mode. The step distance is set to 80% of the straightness of the tool, and the allowance in the cutting parameters is set to 0.15mm for the part and 0.10mm for the bottom. In non cutting transfer, set the transfer type as the mode referring to the previous plane, and set the safe distance of transfer as 3mm. Generate a tool path diagram, as shown in a in Figure 1. Create a tool with a diameter of D = 20mm and a bottom corner radius of R = i.2mm, and then carry out surface milling on several planes such as the upper plane of sand casting, the upper plane of transverse sprue and inner sprue. The machining surfaces are mostly isolated and distributed, with small size or multiple walls around, so the machining allowance is set slightly larger. The specific values are component allowance of 0.3mm and bottom allowance of 0.10mm. The tool path diagram is shown in B in Figure 1.
Use the tool with diameter d = 20mm and bottom corner radius r = i.2mm to create cavity milling. Select the cutting mode following the periphery to further reduce the allowance setting in the cutting parameters, so as to remove more allowance. The tool path is shown in Figure 2. It can be seen from the figure that the main areas of this machining are the connection between the riser and the mold cavity of sand casting and the rough machining of several fillet features. At the same time, it can be seen that due to the large plane structure of sand casting mold template and the small residual size of blank, the processing effect of this tool is not obvious due to the relatively large size or the large fillet radius at the bottom of the tool. It is necessary to create a tool with smaller size to continue processing the mold plate.
Create a tool with diameter d = 16mm and lower fillet radius r = 0.4mm, create a process, and select semi finishing as the mode. The side profile of the sand casting mold template is divided into two times to create the contour milling of the side wall. One time is the side wall of the sand casting cavity, the riser side wall, the sprue side wall, the sprue hole and the side wall of the sand core 2. The other is the side wall of the inner runner of the runner, the upper slope of the extension part of the runner, the side wall of the convex structure on both sides of the cavity, etc., and the cutting allowance is set to 0.10mm. After generating the tool path, the tool path diagram twice is shown in a and B in Figure 3. So far, the semi finishing stage of sand casting mold template is completed, and C in Figure 3 is the 3D effect drawing after the semi finishing is completed.
