NC machining of the mold core of the hottest mobil

NC machining of shell mold core

in modern mold production, with the improvement of the functional requirements of plastic parts, the internal structure of plastic parts has become more and more complex, and the corresponding mold structure has to be complicated. This paper expounds the new design and manufacturing process route used in plastic mold manufacturing: first, use advanced cad/cam software such as pro/engineer or MasterCAM to design 3D graphics of products; Then the mold structure is designed according to the characteristics of the product, and the solid drawing and engineering drawing of the mold cavity are generated; Then in Mastercam, according to the characteristics of the mold cavity, draw the CNC machining process map, draw up the CNC machining process route, input the machining parameters, and generate the tool path; Finally, the dynamic simulation of three-dimensional machining is carried out, and the machining program is generated and transmitted to the NC machine tool for automatic machining. The following is an example of a front shell mold at the beginning of this year, focusing on explaining this processing process. In order to reduce the space, this paper assumes that only the processing part is involved from the generation of the three-dimensional machining process model

I. numerical control machining of the front mold

after the mold is designed according to the 3D graphics of the front shell, the 3D solid drawing of the mold core is converted into IGS graphics format and input into MasterCAM. The 3D diagram of front mold processing technology is shown in Figure 1

Figure 1 3D diagram of front mold machining process

its NC machining process is as follows:

(1) surface grooving rough machining, using φ 16 flat bottom inlaid alloy knife

(2) surface contour semi finishing, using φ 6 flat bottom knife

(3) rough machining of the shape of the curved surface, the pillow position of the battery socket of the front mold, using φ 6 flat bottom knife

(4) rough machining the plane part of the pillow position with ruled surface, using φ 6 flat bottom knife

(5) rough machining the arc surface of the pillow position with ruled surface, using φ 6 flat bottom knife

(6) surface parallel finishing, using φ 10 ball head knife

(7) the corner clearing part of the lower part of the contour finish machining adopts φ 3 flat bottom knife

(8) the corner clearing part of the upper part of the contour finish machining adopts φ 3 flat bottom knife

(9) curved contour finish machining cavity, using φ 3 flat bottom knife

(10) the parting surface of the ruled surface machining cavity adopts φ 16 ball head knife

(11) finish machining the plane part of the pillow with ruled surface, using φ 3 flat bottom knife

(12) finish machining the arc surface of the pillow with ruled surface, using φ 3 flat bottomed knife

they are introduced below

1. Rough machining of surface grooving

adopts double edges φ 16, with a machining allowance of 0.3mm reserved. Feed rate of machine tool, 1500mm/min; Feed speed in Z direction, 500mm/min; Knife lifting rate, 2000mm/min; Spindle speed, 2000r/min

(1) surface parameter

absolute coordinates of safety height, 15mm; Feed incremental coordinate, 1mm; Filter tolerance, 0.025mm. The boundary of the tool takes the shape boundary shown in Figure 1. There is no need to select the inspection surface

(2) the maximum cutting amount of each step in the Z direction of the rough machining parameter

z, 0.4mm; Feed rate of tool diameter percentage, 75%; Actual feed, 12mm. Select the parallel helix milling mode, input a starting point close to the tool path, set the center of the cutting outside the boundary, adopt the helical cutting mode, set the cutting depth as the relative increment mode, and reserve an allowance of 0.2mm

(3) tool path

after setting all parameters, select all machining surfaces in geometry, and select the shape boundary shown in Figure 1 as the machining boundary (expand 1.5 times the tool diameter outward with the workpiece blank outer diameter). There is no need to select the inspection surface. The machining path of the tool is shown in Figure 2

Figure 2 rough machining tool path of contour grooving

2 Surface contour semi finishing

adopted φ 6 flat bottom superhard alloy knife, further process the residual allowance of sharp corners or small fillets, and reserve a processing allowance of 0.15mm. Feed rate of machine tool, 500mm/min; Feed speed in Z direction, 500mm/min; Knife lifting rate, 2000mm in order to find out the current situation of primary plastic in China/min; Spindle speed, 1800r/min

(1) contour parameter

each height drop of cutting tool is 0.15mm; The cutting point is selected within the boundary; The cutting depth is selected as the relative depth, 0.2mm

(2) tool path

after setting all parameters, select all machining surfaces in geometry, and the machining path of the tool is shown in Figure 3

Figure 3 contour semi finishing tool path

3 Contour machining of curved surface

rough machining tool path of curved surface is used to process the battery socket pillow of the front mold, and φ 6 flat bottom knife alloy knife, with a machining allowance of 0.15mm reserved

(1) shape parameter

absolute coordinates of safety height, 15mm; Feed incremental coordinate, 1mm; Filter tolerance, 0.025mm. Multi layer cutting parameters are used to set the cutting times and cutting parameters in the XY plane, which are determined according to the machining allowance: rough cutting times, 2 times; Step length, 4mm; Number of finish cutting, 0; Step length, 0.5mm. Set the appropriate path of feeding and withdrawing. Because the machining depth is only 2mm, depth cutting is not used here

(2) tool path

after setting all parameters, select the shape shown in Figure 1 in the geometry chain. Enter the operation management menu from the toolpaths/operations command, simulate the tool path with the backplot run command, and check whether there is a problem with the contour and tool milling path. The machining path of the tool is shown in Figure 4

Figure 4 contour processing path

4 Ruled surface processing

the ruled surface processing method is adopted to roughen the plane part of the pillow position, and the tool adopts φ 6 flat bottom alloy knife, with a machining allowance of 0.1mm reserved

(1) the tool path parameters of ruled surface

the cutting method adopts reciprocating cutting; Cutting spacing, 0.1mm; Cutting allowance, 0.1mm; Rapid feed depth (absolute dimension), 15.0mm, left, tool left compensation

(2) tool path

after setting all parameters, select two ruled lines as shown in Figure 1 in the geometry chain. The machining path of the tool is adjusted, and the position diameter is shown in Figure 5

Figure 5 processing path of the ruled surface of the occipital plane part

similarly, the ruled ruled ruled surface processing mode is used to roughen the arc part of the other half of the occipital position, and φ 6 flat base alloy cutter, the tool parameters and ruled surface parameters remain unchanged, and a machining allowance of 0.1mm is reserved. The machining path of the tool is shown in Figure 6

Figure 6 processing path of straight line surface of pillow arc part

5 Surface parallel machining

finish all surfaces by surface parallel machining. Tool use φ 10 ball head cutter, leaving no machining allowance. Feed rate of machine tool, 1300mm/min; Feed speed in Z direction, 500mm/min; Knife lifting rate, 2000mm/min; Spindle speed, 2500r/min

(1) surface parameter

absolute coordinates of safety height, 15mm; Feed incremental coordinate, 1mm; 0.3mm machining allowance is reserved. Because you want to finish machining all the surfaces, there is no need to determine the boundary of the tool here, and the inspection surface is not used

(2) surface parallel processing parameters

maximum machining step, 0.1mm. This option can set the traverse feed of the tool. The smaller the value is, the more accurate it is. The smoother the machining surface is, but the longer the time and program to generate the NC program are. The cutting method is defined as back and forth cutting. The cutting angle can be set as the included angle between the machining tool path and the X axis in the current composition plane, which is set to 45 ° here. The machining path of the tool is shown in Figure 7

Figure 7 surface parallel machining path

6 Surface contour semi finishing

the contour cutter path is used to finish the corner clearing part of the lower part. Tool use φ 3 flat bottom superhard alloy knife

(1) machine parameter

feed rate of machine tool, 500mm/min; Feed speed in Z direction, 500mm/min; Knife lifting rate, 2000mm/min; Spindle speed, 3500r/min. Open the coolant, reserve 0.3mm machining allowance, and do not use the inspection surface. The boundary of the tool is shown in Figure 8

figure 8 tool boundary

(2) contour parameter

each height drop of cutting tool is 0.15mm. The cutting point is selected within the boundary; Adopt the forward milling reciprocating mode to feed; The absolute depth is selected as the cutting depth, with the minimum depth of 0.0mm and the maximum depth of -4.0mm. The machining path of the tool is shown in Figure 9

the same contour cutter path is used to finish the corner clearing part of the upper part, which is still used φ For the flat bottom cutter of 3, the tool parameters, surface parameters and processing parameters are the same as before. Select all processing surfaces as the processing surfaces, and the boundary is the shape boundary shown in Figure 10. The minimum machining depth is -1.5mm and the maximum machining depth is -4.0mm. The machining path of the tool is shown in Figure 10

Figure 9 contour machining path of lower corner clearing part

Figure 10 contour machining path of upper corner clearing part

7 Surface contour finish machining

finish machining the entire cavity with contour tool path. Tool use φ 3 flat bottomed knife. The tool parameters and machining surface parameters are the same as before, and the machining boundary is the boundary shown in Figure 11. Although the final surface finish machining, still leave 0.3mm margin for subsequent EDM. Select all machined surfaces as finish machined surfaces: each height drop value is 0.1mm, the minimum machining depth is -4.0mm, and the maximum machining depth is -9.1mm. The machining path of the tool is shown in Figure 11

Figure 11 contour machining path

8 Ruled surface machining

the ruled surface machining method is used to finish the parting surface. Tool use φ 16 flat bottom alloy knife, with a 0.1mm oil filling system reserved, the oil leakage generally shows the working allowance at the connection of buffer valve, oil return valve, oil delivery valve, oil pump and pipeline. The cutting method adopts reciprocating cutting, and the cutting spacing is 0.2mm. The machining path of the tool is shown in Figure 12. The plane part and circular arc surface of the pillow are also finished by using the ruled surface machining mode. Tool use φ 3 flat base alloy cutter, without machining allowance, with a cutting spacing of 0.2mm

Figure 12 processing path of parting surface ruled surface

II. NC processing of rear mold

3D processing process diagram of rear mold, as shown in Figure 13

Fig. 13 3D diagram of the processing technology of the rear mold of the side shell

its numerical control processing technology is as follows (similar to the front mold, limited to space, it will not be expanded):

(1) surface grooving rough machining, using φ 25 flat bottom inlaid alloy knife, with a margin of 0.4mm

(2) surface contour semi finishing, using φ 12 flat bottom knife, with 0.15mm allowance

(3) surface parallel finishing, using φ 10 ball head cutter without machining allowance

(4) the shape of the surface, and the len lens position of the front mold processed in contour mode, using φ 4 flat bottomed knife

NC machining of face shell copper electrode

three dimensional machining process diagram of copper electrode, as shown in Figure 14

Figure 14 3D diagram of copper electrode processing technology

its NC processing technology is as follows (limited to space, it will not be expanded):

(1) rough machining the reference position of copper electrode by adopting the contour processing method of curved surface, using φ 16, without machining allowance

(2) rough machining all surfaces of copper electrode by surface parallel machining, using φ 16, with a machining allowance of 0.35mm

(3) adopt the contour machining method of curved surface to semi finish the curved surface of copper electrode φ 6, with a machining allowance of 0.1mm

(4) the lens part is processed by grooving, and φ 6, with a machining allowance of 0.3mm

(5) rough and finish the lens assembly position by using the shape processing method of curved surface, and φ 1, without machining allowance

(6) finish machining all curved surfaces of copper electrode by means of surface parallel machining φ 6 ball head knife