Injection mold for guide pipe bracket
The guide tube bracket belongs to the category of medical devices, and the product diagram is shown in the figure. The maximum external size of the product is 59.40mm x 27.83mm x 25.0mm, the average plastic thickness is 1.43mm, the plastic material is ABS, the shrinkage rate is 1.005, and the plastic quality is 4.70g. Plastic parts technical requirements for the existence of peak, injection dissatisfaction, flow lines, pores, warping deformation, silver lines, cold material, jet lines, bubbles and other defects. ABS materials used in plastic parts must meet the general requirements of medical devices.
As can be seen from the figure, the basic shape of plastic parts is a hollow cylinder. The middle outer diameter has a circle of trapezoidal boss, the mouth has a circle of irregular flange. Using three factor analysis method to analyze plastic parts, plastic parts mould direction analysis there are two kinds of design scheme of the first kind of plan to put up plastic parts design, the analysis results indicate the parts diagram, stand design, parting surface choose irregular convex platform on the surface of cylinder diameter in need design hough slide block core pulling. The side gate is designed at the edge of the irregular flange, and the ejector system USES a thimble.
The second direction of opening mold is to put plastic parts upside down design, that is, plastic parts of the cylinder outer diameter of the inverted button do not need to design huff slider, where the inverted button is formed by the front mold and the back mold respectively. The two ends of the plastic piece need to design the slider, that is, the slider's movement direction and the axis of the cylinder coincide. This design scheme has little impact on the appearance of plastic parts, and can also produce good plastic parts. Due to the small size of plastic parts, floating sliders are required for the upside down design to push out plastic parts, and the core pulling of the long side sliders needs to lag behind. Therefore, the mold cost will rise and the injection cycle will be long. Therefore, this scheme is not adopted.
The size of plastic parts is small, the precision is high, the mold design position is 1 out 1, the mold blank is non-standard mold blank 2527, is based on the standard mold blank, increase and reform of the mold bottom plate. Because it is a single mold cavity, the gate cover and positioning ring are eccentric 34, the top rod 13 is also eccentric 34, the top rod 13 is fixed at the bottom of the thimble plate with headless screw 17. Melt plastic from the gate sleeve into the main channel between the two huff slider, and then through the bottom of huff slider from the plastic part of the edge of the irregular flange into glue, the formation of side gate.
Plastic part belongs to the deep tube shape, the packing force of the back mold core is larger, after the opening of huff slider, the ejection of the plastic part if only rely on the ejection of the ejector will make the plastic part of serious deformation, difficult to ejector. Similarly, if only rely on the push out of the plate, plastic parts will stick to the push plate. So the die structure of secondary ejecting is designed to overcome the ejecting problem. Core 3 ACTS as a push plate insert. After mold opening, under the action of the clamping machine (composed of parts 20, 21, 22, 23, etc.), the whole mold is separated from the bottom plate of the mold, and the screw is used to limit the position. The back die insert 5 is fixed on the bottom plate of the mold by the pressing block 14, and the back die insert 5 is separated from the plastic parts and other mold parts. Therefore, the whole set of die blank and the back die play the role of pushing the plate. Finally, the ejector mechanism of the injection molding machine pushes the ejector rod 13, ejector pin 12 on the ejector plate and other ejectors push the plastic part from the back die top, and the nozzle material is also pushed out.
In addition to cooling and transporting water in the design of huff slide block, cooling water pipe 16 is designed in insert 5 of the rear mold, which is a standard element and sealed by sealing ring 15. Although it is necessary to design non-standard die blank and increase the cost of die blank, the structure of the die is simple and reliable, and the secondary ejection is effectively realized. The design idea is worth popularizing. Injection Mold