Design of the automatic cutting mold for the upper

The structure of TB injection molding machine (or T-type injection molding machine) is shown in the following figure, including mold locking cylinder 1, mold locking mechanism 3, moving plate 4, head plate 7, control panel, nozzle, injection cylinder 10, barrel 12, hopper 13, injection cylinder 14, body 15, etc, Its unique mechanism is to add a set of "runner push plate" mechanism 6 to the head plate of the existing technology injection molding machine. The mechanism is connected with the hydraulic system of the molding machine through a group of oil cylinders 8, solenoid valves, etc. through the computer control program, the mechanism can make the reciprocating motion in the head plate according to the required time. Push the push rod on the mold through the channel push plate to cooperate with various types of molds to complete various actions, so as to achieve the purpose of reducing mold opening cost, improving injection efficiency, reducing injection cost, etc

tb injection molding machine can easily realize the automatic cutting of side gate; Simply realize the automatic separation of point gate, point and side compound gate and runner. It is very simple to realize the vertical core pulling, side core pulling and flip chip of the static mold

this article introduces the design of the side gate automatic cutting mold on TB injection molding machine

as long as the gate is within the range of the runner push plate (L x W x D - D) of the TB injection molding machine in Figure 2.2, the side gate injection mold can realize the automatic cutting of the gate

2. Design of injection mold with automatic cutting of side gate of moving die cutter

figure 4.1 shows the side gate automatic cutting injection mold used on TB injection molding machine (1) regularly check whether there is oil leakage at the host and oil source. Compared with the mold used in ordinary injection molding machine, the main structure is the same, and the additional parts include (per cavity) gate cutter 6, cutter reset block 8, spring 5 and push rod 9. The figure at the bottom left a is the side projection of the gate cutter 6 and the cutter reset block 8. The action principle (sequence) is: injection (the push plate 6 of the injection molding machine channel makes the push rod 9 in Figure 4.1 in the position shown in the figure under the action of the push plate cylinder 8, and the melt plastic enters the cavity 7 through the gate between the channel 12, the gate cutter 6 and the cutter reset block 8 until the filling is completed) - gate cutting (after the product 7 is cured and molded, the runner push plate 6 of the injection molding machine retreats, making the gate cutter 6, cutter reset block 8 and push rod 9 in Figure 4.1 move forward under the action of spring 5, separating the runner 12 from the product 7) - mold opening (the dynamic mold fixing plate 1, dynamic mold 4, etc. retreats with the injection molding motor plate 4 in Figure 2.1, separating the static mold 10 from the dynamic mold 4, etc., and the product 7 and runner 12 remain on the dynamic mold insert 14 until the end of mold opening) - products Ejection of flow channel (the ejection rod on the top of the injection molding machine advances, driving the push rods 3, 13, reset rod 15, etc. in Figure 4.1, pushing the product 7 and flow channel 12 out of the moving die insert 14, taking it away or automatically falling) - mold closing (the ejector rod and runner push plate 6 on the top of the injection molding machine are reset, the moving plate 2 drives the moving die 4 in Figure 4.1 forward, the push rod 3, 13 and the push rod fixed plate 2 are reset under the action of the reset rod 15; the gate cutter 6 and spring 5 are reset under the action of the push rod 9 and the cutter reset block 8; until the end of mold closing)

precautions for design and assembly: ① the head shape of the gate cutter 6 is shown in the enlarged drawing at a (d) and B (E). The length is taken as the length of the gate. Because the assembly hole on the moving die insert 14 is generally processed by wire cutting, limited by the wire cutting pre hole drill, it is generally taken as 1.6 ~ 2.0 mm. When processing the gate on the gate cutter, the width is about 3mm wider than that of the gate, generally 5 ~ 6 mm. The height is generally 10 ~ 15 mm. The gate inclination K is generally taken as 15 ° or 20 °, and the matching dimension a with the cutter reset block 8 is theoretically 0. In fact, it is often taken as 0.05 ~ 0.1 mm, which has prevented the gate cutter 6 from being damaged. The action stroke of the gate cutter 6 to cut off the gate is generally 3 mm. ② The tail shape of gate cutter 6 is generally cylindrical. In order to facilitate assembly, the gate cutter 6 can be made into an oblique angle (wire cutting or bench machining) at the inlet of the moving die insert 14. Figure 4.1, figure B and figure C are two evolution forms. Figure B shows that adding a cylindrical pin 16 under the gate cutter 6 and placing the spring 5 outside the cylindrical pin 16, the processing technology and assembly technology are better than the above cases. When the gate is large, that is, the runner is large, it can also be made as shown in Figure C, but generally speaking, it is not as good as the above two cases. ③ The spring force is greater than the shear strength of the plastic at the gate. Theoretically, the spring force should be calculated, but because it is difficult to calculate, in fact, the diameter is generally taken as the standard sswl ф 10～ ф 14 rectangular spring (or similar standard green rectangular spring) is OK. ④ The plane shape of the products at the gate can be straight line or curve, convex or concave. When residual burrs are allowed at the gate, the distance between the gate cutter and the product is more than 0.6mm; When the product is not allowed to leave residual burrs, the form of figure 4.1, lower right F, can be used to make the residual gate after cutting the gate concave into the whole working face. This case can be easily realized. ⑤ The function of the cutter reset block 8 is not only to cut off the movement space of the gate for the gate cutter 6, but also to give a deformation space to the runner. Therefore, the width dimension should be at least the same as that of the gate cutter 6. Generally, one side is 0.2mm larger, which has prevented the gate cutter 6 from being damaged. When the runner is located in the static die and the end face of the cutter reset block 8 needs to process the runner, its width should be 3mm larger than the runner width. The length of cutter reset block 8 is too short, and the flow channel is easy to be cut off. If it is too long, the pressure acting on the oil cylinder is too large, which is generally 5 ~ 6mm. The effect of gate processing on the gate cutter 6 is the same as that on the cutter reset block 8. The specific selection depends on the position of the mold parting surface in the product. ⑥ Since the injection pressure and spring pressure at the time of injection finally act on the oil cylinder through the channel push plate, the force of the oil cylinder must be greater than the sum of the force of the channel at the time of injection and the pressure of the spring. Therefore, especially when there are multiple gates, the width of the runner at the gate must be small. Generally, trapezoidal runner should be used instead of semicircular runner. When trapezoidal runner is used, its width depth ratio is about 1 ~ 1 Especially in the long-term action 2. ⑦ When the product is small, such as the multi cavity mold of ring parts, the cutter and the cutter reset block can be in the same cavity, and the gate can be cut off by the movement of the product. ⑧ When the two gates are very close to each other, the two gates can share a cutter reset block. When the cross flow channel is long, especially when injecting soft materials, pay attention to the cross flow channel and push rod ejection; When the mold is a single cavity and single gate, pay attention to the cross channel and push rod ejection to prevent ejection eccentricity. ⑨ The side gate automatic cutting injection mold is generally suitable for products with small thickness at the gate. When it is used for shell products, the appearance should leave traces of inserts. At the same time, because the holes of the assembly cutter and the cutter reset block are generally processed by wire cutting, the design should not only pay attention to the influence of the corner r on the products, but also consider the influence of the corner r on the fitting accuracy of the cutter and the cutter reset block, so as to avoid overflow and failure of the cutter. ⑩ The side gate automatic cutting injection mold is not suitable for special gates, such as molds with dozens of gates and dozens of gates. Special attention should be paid to the design

3. Design of injection mold with side gate automatic cutting of static die cutter

Figure 4.2 shows another case of side gate automatic cutting injection mold used on TB injection molding machine. Different from figure 4.1, the gate cutter 6 is installed into the static die 9, while the cutter reset block 8 is installed into the dynamic die insert 15. The figure shows the mold closing state. The action principle (sequence) is as follows: injection (melt plastic enters the cavity 7 through the channel 12 until the filling is completed) - gate cutting (after the product 7 is cured and molded, the channel push plate 6 in Figure 2.1 advances under the action of the push plate cylinder 8, pushing the push rod 9, the gate cutter 6, the cutter return block 8 and the spring 5 in Figure 4.2 forward, separating the channel 1, whether it is a Dutch citizen or not, 2 from the product 7) - mold opening (the moving die fixing plate 1, moving die 4, etc. retreat with the injection molding machine plate 4 in Figure 2.1, so that the static die 10 is separated from the moving die 4, and the product 7 and the flow channel 12 remain on the moving die insert 14. At the same time, the cutter reset block 8 and the spring 5 are reset until the shape, weight, size and other aspects of the sample are paid attention to when selecting the sample) - products Channel ejection (the ejection rod on the injection molding top advances, drives the push rods 3, 13 and reset rod 15 forward, and ejects the product 7 and channel 12 out of the moving die insert 14, which is removed or automatically dropped) - mold closing (the ejection rod on the injection molding top and the channel push plate are reset, the moving plate 2 drives the moving die 4 in Figure 4.2 forward, the push rods 3, 13 and the push rod fixed plate 2 are reset under the action of the reset rod 15; the push rod 9 and the gate cutter 6 are reset under the action of the cutter reset block 8; until the end of mold closing) 。

special precautions for design: ① the spring force of spring 5 must be greater than the force of the flow channel during injection. ② Generally, do not use this structure

4. Design of the injection mold with the outer gate of the runner push plate automatically cut off

figure 4.3 shows another case of the injection mold with the side gate automatically cut off whose gate is located outside the range of the runner push plate. In this case, on the basis of figure 4.1, a transition push plate 12 and screw 13 are added to the fixed plate 11 of the static die, and the action sequence is the same as figure 4.1. In the figure, the action of the push rod 9 is applied through the runner push plate 14 and the transition push plate 12, and the screw 13 is used for positioning and limiting

5. Use of side gate automatic cutting injection mold on ordinary injection molding machine

when the side gate automatic cutting injection mold shown in Figure 4.1, if the push rod 9 is outside the range of the locating ring D of the runner push plate in Figure 2.2, if it is used on ordinary injection molding machine, it is the same as the ordinary side gate injection mold, but the handle must be cut manually; When the push rod 9 in Figure 4.1 is located within the range of the locating ring D of the channel push plate in Figure 2.2, if it is used on the ordinary injection molding machine as the ordinary side gate injection mold, a pad should be added between the channel push rod 9 and the cutter reset block 8

6. Injection molding operation procedure of side gate automatic cutting off injection mold

figure 4.1 and figure 4.3. The semi-automatic and automatic injection molding operation sequence of side gate automatic cutting off injection mold of moving die cutter is: mold locking - injection - push plate retreat - mold opening - push in - push back, push plate advance, and mold locking

Figure 4.2 the semi-automatic and automatic injection operation sequence of the injection mold with the side gate of the static die cutter automatically cutting off is: mold locking - glue injection - push plate in - mold opening - push in - push back, push plate back, and mold locking

7. conclusion

as TB injection molding machine is a new model, the design and injection operation of various molds used on TB injection molding machine are different from those of ordinary injection molding machines. There must be many improvements and new discoveries. Please give your valuable comments. thank you! (end)