Complicated core-pulling injection mold for the shell of the printer and fax machine
The shell of the printer and fax machine is shown in Figure 1. The maximum size of the product is 478.97 mm x 234.44 mm x 148.05 mm, the average thickness of the plastic part is 1.80 mm, the material of the plastic part is PS-HI, the shrinkage rate is 1.005, and the quality of the plastic part is 478.8 gram. The technical requirements for plastic parts are that there must be no defects such as peaks, dissatisfaction with injection molding, flow lines, pores, warpage deformation, silver streaks, cold materials, jet lines, etc. Nihong etching is required on the surrounding surface of the plastic part. Matte pattern on the top.
It can be seen from Figure 1 that the plastic structure is a complex shell formed by an irregularly enclosed structure on four sides. See the attached file for the 3D product drawing and 3D mold drawing. There are large-area heat dissipation grid holes and mold undercuts on the four sides of the plastic part, and 4 large slider cores need to be designed. The boundary of the slider is on the curved surface, therefore, it is necessary to design the parting surface well. The connecting bridge in the middle of the plastic part has deep bones, thin shape and poor rigidity. The structure of the plastic part is irregular, and the parting surface is a complex irregular parting surface. The structure of the plastic part is complex and the size is large, but the top area of the plastic part is small, only the edge part has a glue position, and most of the local area is hollow, which brings difficulties to the design of the mold ejection system.
The product size is large, the mold structure is complex, and there are slider core pullers on all four sides. The mold design cavity ranks 1 out of 1, and the injection molding machine has a 450-ton Nissan injection molding machine. The gating system is designed with a point gate design, and 4 point gates are designed on the top of the plastic part. The mold base is a non-standard simplified fine nozzle mold base 7094. For injection molds with large sliders on all sides, the design adopts a simplified fine nozzle mold base. Due to the absence of 4 guide posts, the mold space is effectively saved. Due to the long runner, the long condensate of the gating system, and the irregular shape, in order to prevent the nozzle material from falling when the manipulator is used for injection molding, an anti-rotation column is designed on the sky side of the mold to locate the nozzle material and facilitate the gripping of the manipulator.
The structure of the plastic part is complex, and there are many bone and column positions in the glue position. The design of the insert is a very critical part. By reasonably splitting the inserts, the processing difficulty is reduced and the processing efficiency is improved. For complex molds, the most effective method for splitting inserts is the full inserting method, that is, splitting to make inserts. The splitting of inserts is shown in Figure 5 and Figure 6.
