Design Of Hydraulic Core-pulling Injection Mold For Multi-way Pipe Joint+3d

The multi-way pipe joint products are shown in Figure 1. The products are divided into two types: AB. The maximum dimension of A is 137.5 mm x 76.30 mm x 129.00 mm, the average thickness of plastic parts is 2.00 mm, the material of plastic parts is PP, and the shrinkage rate is 1.013 , the mass of plastic parts is 64.50 grams. The maximum external dimension of B is 145.0 mm x 47.30 mm x 92.00 mm, the average thickness of plastic parts is 2.00 mm, and the weight of plastic parts is 51.50 grams. The technical requirements for plastic parts are that there shall be no defects such as peaks, unsatisfactory injection molding, flow lines, pores, warpage deformation, silver lines, cold materials, and spray lines.

            

A product

           

             

Product B

Figure 1 Multi-way pipe joint diagram

Figure 2 Mold Design Ranking Diagram





Figure 3 Combination diagram of rear die slider



As can be seen from Figure 1, the plastic part A is a complex six-way pipe joint, one of which is threaded on the outer diameter of the edge of the mouth, and the other is inclined. The plastic part B is a three-way pipe joint, and the inner hole core pulling distance is longer. The difficulties in the design of multi-pass pipe joint molds are as follows: 1. The direction of mold opening, that is, the analysis of both sides of the movable and fixed molds of the plastic part, and the analysis of which side the slider is facing. 2. Determination of cylinder core-pulling and inclined guide column core-pulling. 3. The combination analysis of the slider in the inner hole, that is, the neutron junction can not hinder the neutron movement, the neutron junction can not have a drape, and the neutron cannot be bent and deformed under the injection pressure.

In this set of molds, the analysis of the mold opening direction of the plastic parts is the key. For plastic part A, orient the slanted joint towards the movable die, as shown in Figure 2. For plastic part B, turn the cruciate position toward the movable mold and the maximum core pulling direction toward the outside. The mold design cavity ranking is 1+1, the mold base is a standard mold base 4060, and the gating system is a latent gate.

                          Figure 4 Analysis of mold ranking



According to the structure of the plastic parts, the mold opening direction is determined and the ranking is done. The slider core pulling of this set of molds adopts hydraulic cylinder core pulling. In the mold of multi-pass pipe fittings, it is often necessary to do a good job of the two neutrons in the inner hole when the inner hole is cored. Generally speaking, when the core-pulling distance exceeds 70, the oil cylinder must be used for core-pulling. If the inclined guide post is used for core pulling, the strength and rigidity of the inclined guide post are insufficient, and the length of the inclined guide post is too long and protrudes out of the mold. Another reason is that the core pulling of the oil cylinder is convenient to control the timing of the core pulling, so that the neutrons touching each other can well seal the glue.

    The precautions for cylinder core pulling are as follows;

1. Do a good job of guiding the slider. The guide post and guide sleeve can usually be designed to guide the piston rod and increase the rigidity. It can also be used as a guide on the bead, such as this set of molds.

2. For the connection of the oil cylinder, the piston rod of the oil cylinder cannot be directly connected to the slider. Instead, screw a ring on the head of the piston rod. Snap the ring into the T-slot at the end of the slider.

3. Confirmation of cylinder core pulling stroke. It is usually necessary to design a travel switch at the initial two positions of the stroke to control the operation of the cylinder.

4. Selection of cylinder size. To design the core pulling of the cylinder, it is necessary to confirm that the piston rod exerts pressure in the rod cavity or in the rodless cavity. If necessary, it needs to be selected by calculation.

5. For some molds, it is necessary to analyze whether the cylinder is pushed out or retracted. That is, the slider core-pulling action required for mold core-pulling.

6. When the cylinder is cored, the molding cycle of the mold will be affected, so it needs to be confirmed by the customer.

7. When designing the mold for the core pulling of the oil cylinder, the oil pipe needs to be properly fixed to prevent the action of the mold from being affected. If the mold operation balance is required, the oil collector is designed to uniformly enter and exit the oil inlet and outlet joints.

8. When the cylinder is cored, the oil temperature needs to be kept stable. Cylinder core pulling should be used with caution in high temperature molds.

9. When the cylinder is core-pulled, the shovel base must be used to lock the cylinder. The core-pulling of particularly small holes can be unlocked and locked by the power of the oil cylinder itself.