KR100754803B1 - Apparatus for balancing the filling of injection molds - Google Patents

Abstract

An apparatus for balancing filling of an injection mold is provided to prevent the temperature difference between resins supplied to each cavity. An apparatus for balancing filling of an injection mold includes a first runner; a branch portion formed at an end of the first runner; a plurality of second runners branched off from the branch portion; and a partition wall(30) inserted in the branch portion so as to vary the flow of the resin supplied to each cavity of the injection mold.

Description

Apparatus for balancing the filling of injection molds}

1 is a data showing a simulation result of the injection molding filling apparatus according to the prior art.

Figure 2 is a plan view showing the structure of a typical injection molding filling apparatus.

Figure 3 is a plan view showing an injection molding uniform filling apparatus according to an embodiment of the present invention.

4 is a cross-sectional view taken along the line H-H 'of FIG.

Figure 5 is a data showing the simulation results of the injection molding uniform filling apparatus shown in FIG.

<Explanation of symbols for main parts of the drawings>

10: hopper 21: first runner

22a: runner 2a 22b: runner 2b

23a: runner 3a 23b: runner 3b

23c: 3d runner 23d: 3d runner

25: first branch 26a: second branch

26b: second branching portion 30: partition wall

40: nozzle 50: cavity

The present invention relates to an injection molding uniform filling device.

Injection molding using plastic resin has been used in the past to manufacture daily necessities and exterior materials, but is widely used to manufacture mechanical elements by replacing metals due to high productivity and development of new materials. High product precision is required for use in these mechanical elements, and multi-cavity structure is required to increase the number of products per mold to ensure high productivity. In order to secure such precision and productivity, not only the processing of the mold but also the molten resin is required to be balanced in each cavity of the mold. However, even geometrically balanced runners produce non-uniform filling.

1 is data showing a simulation result of the injection molding filling apparatus according to the prior art. (A) of FIG. 1 is data which shows the magnitude | size difference of a speed, (b) is data which shows a temperature distribution, and (c) is data which shows the difference of filling time. Referring to FIG. 1, as the branching proceeds, the temperature of the outer diameter of the runner increases due to the shearing heat, and after the branching occurs, a left and right temperature difference occurs. . That is, when the injection speed is high, the temperature of the wall surface is higher than the central portion due to the temperature rise due to the shear rate at the wall surface, and therefore, the speed difference between the branched tertiary runners when branching from the secondary to the tertiary runner is different. It happens. This temperature difference causes a problem of unbalanced filling in each cavity.

The present invention provides an injection molding uniform filling apparatus which enables uniform filling by preventing a difference in temperature distribution of the resin supplied to each cavity.

According to an aspect of the present invention, an injection molding uniform filling device for supplying resin to a plurality of cavities, a first runner, a branch formed at the end of the first runner, a plurality of second branches branched from the branch; It is possible to provide an injection molding uniform filling apparatus including a runner and a partition wall interposed at a branch so that the flow of the resin changes.

The branch may be formed to have a larger cross-sectional area than the first runner.

The partition wall may extend from one inner wall of the branch to abut the other inner wall facing the inner wall of one side, and the partition wall may be shaped to be spaced apart from each other inner wall facing each other so as to separate the flow of resin. .

The partition wall may include a first partition wall extending from one inner wall of the branch portion and a second partition wall extending from the other inner wall facing the inner wall of one side, and an end portion of the first partition wall and an end portion of the second partition wall are spaced apart from each other. May be

The partition wall may be interposed to be adjacent to an end of the first runner.

On the other hand, according to another aspect of the present invention, the injection molding uniform filling device for supplying a resin to a plurality of cavities, the first runner, the first branch formed at the end of the first runner, from the first branch 2a runner and 2b runner branching, 2a branching portion formed at the end of the 2a runner, 3a runner and 3b runner branching from the 2a branching portion, 2b branch formed at the end of the 2b runner An injection molding uniform filling apparatus including a base, a 3c runner and a 3d runner branching from a second branch, and a partition wall interposed between at least one of the second branch or the second branch so as to change the flow of the resin are presented. can do.

The partition wall may extend from one inner wall of the second a branch part or the second b branch part to be in contact with the other inner wall facing the one inner wall, and the partition wall may be formed from both inner wall faces of the second a branch part or the second b branch part opposite to each other. Each may be spaced apart from each other.

The partition wall may include a first partition wall extending from one inner wall of the second a branch part or a second b branch part, and a second partition wall extending from the other inner wall facing the one inner wall, and an end portion of the first partition wall and the second partition wall. The ends of the may be shaped to be spaced apart from each other.

Other aspects, features, and advantages other than those described above will become apparent from the following detailed description of the invention including the drawings and the claims.

Hereinafter, a preferred embodiment of the injection molding uniform filling apparatus according to the present invention will be described in detail with reference to the accompanying drawings, in the description with reference to the accompanying drawings, the same or corresponding components are given the same reference numerals and Duplicate explanations will be omitted.

2 is a plan view showing a general injection molding apparatus. Referring to FIG. 2, the hopper 10, runners 21, 22a, 22b, 23a-23d, branches 25, 26a, 26b, nozzle 40, and cavity 50 are shown.

The resin, which is a raw material for injection molding, is supplied to the injection molding apparatus through the hopper 10. The resin is supplied in a liquid state at high temperature and high pressure, and is supplied to each cavity 50 through the nozzle 40 through the runner.

In the case of an injection molding apparatus having a plurality of cavities 50, the runner and the resin supplied through the runner are branched one or more times. For example, in the case of an injection molding apparatus having two cavities 50, the runner and the resin are branched once so that resin is supplied to each cavity 50, and the injection molding apparatus having four cavities 50 is provided. In case of branching twice. In this embodiment, an injection molding apparatus having four cavities 50 will be described. That is, in this embodiment, the runner and the resin branch twice.

Referring to FIG. 2, the first runner 21 connected to the hopper 10 is first branched to the second a runner 22a and the second b runner 22b. Thereafter, the second a runner 22a branches into the third a runner 23a and the third b runner, and the second b runner 22b branches into the third c runner and the third d runner 23d.

Resin supplied to the first runner 21 through the hopper 10 is supplied to each cavity 50 through two branches. At this time, if a difference in the time required for the resin to arrive and supply to each cavity 50 occurs, it is impossible to achieve a uniform filling. Therefore, the moving speed of the branched and moving resin is an important parameter that enables uniform filling. However, since the moving speed of the resin has a correlation with the temperature of the resin, the temperature distribution of the resin supplied to each cavity 50 also becomes an important parameter that enables uniform filling, and thus, the supply speed is supplied to each cavity 50. It is necessary to adjust the temperature distribution of the resin to be uniform.

While passing through the first runner 21, when the flow rate of the resin is slow, the resin adjacent to the inner wall of the first runner 21 suffers heat loss to the outside. Therefore, the resin located at the center of the first runner 21 is in a relatively high temperature state, and the resin adjacent to the inner wall is in a relatively low temperature state, and a temperature difference occurs between them. However, when the inflow speed of the resin is high, the amount of heat generated by the shear force between the outer wall and the resin is greater than the heat loss caused by the outer wall of the runner, and the temperature at the outer wall becomes higher than the inner wall, causing a temperature difference.

In the state which kept such a temperature difference, resin branches (primary branch) to 2nd a runner 22a and 2nd b runner 22b.

After the first branch, a temperature difference occurs between the resin flowing through the right part and the left part of the second a runner 22a. The same applies to the second b runner 22b.

If the cavity 50 is coupled to the ends of the 2a runner 22a and the 2b runner 22b, such a temperature difference may not be a big problem. Although a gradient of temperature is formed inside each runner, the temperature distribution of the resin flowing through the second runner 22a and the second runner 22b is not different.

However, this is not the case when branching two or more times as in this embodiment. Referring to FIG. 2, when the third a runner 23a branched from the second a runner 22a and the third b runner 23b are compared, the resin flowing in the right part of the second a runner mainly flows into the third a runner 23a. It is confirmed that the resin that flowed into the left portion of the second a runner mainly flows into the third b runner 23b. In other words, the resins flowing in the third a runner 23a and the third b runner 23b are different in temperature distribution from each other. The same applies to the third c runner 23c and the third d runner 23d branched from the second b runner 22b.

In order to solve such a temperature distribution difference, a partition is provided in the 2nd branch part 26a formed in the edge part of the 2nd runner 22a in this embodiment.

Figure 3 is a plan view showing a branch of the injection molding uniform filling apparatus according to an embodiment of the present invention, Figure 4 is a cross-sectional view taken along the line H-H 'of FIG. 3 and 4, the second a runner 22a, the second a branch part 26a, the third a runner 23a, the third b runner 23b, the partition wall 30, the first partition wall 31, The second partition 32 is shown.

The partition 30 is interposed in the branch 26a, and means for performing a function of mixing the resin by changing the flow of the resin flowing into the branch 26a, thereby reducing the temperature difference of the resin flowing through the runner to be.

Referring to FIG. 3, the temperature difference of the resin occurs between the resin flowing through the center of the runner and the resin flowing on the side of the runner. This is because heat loss and shear heat are generated through the inner wall of the runner as described above.

In order to reduce this temperature difference, the partition is interposed a predetermined distance from the left and right of the branch portion 26a. That is, it interposes so that the center part of the branch part 26a may be interrupted | blocked. In the case of having such a structure, the resin supplied toward the center of the branch portion 26a is blocked by the partition wall, separated in both the left and right directions, and flows to be adjacent to the left or right inner wall of the branch portion 26a. do. Through this, the resin flowing through the center of the runner and the resin flowing through the side surface are mixed, and the temperature difference between them is reduced. The resin mixed through the partition wall is further spread evenly inside the branch portion 26a, and branches and flows to the third a runner 23a and the third b runner 23b.

As such, since the temperature difference of the resin is reduced while passing through the branching portion 26a in which the partition wall is interposed, a difference in temperature distribution almost occurs between the resin flowing through the third runner 23a and the third b runner 23b. Will not. This means that a difference in temperature distribution does not occur between the resins supplied to the respective cavities 50, and that uniform filling can be achieved in each cavity 50.

On the other hand, when a partition is provided in the branch part 26a, the cross-sectional area of the branch part 26a becomes narrow, and there exists a possibility that resin may not flow smoothly. In order to solve this problem, by making the cross-sectional area of the branch part 26a larger than the cross-sectional area of the runner, the branch part 26a can be expanded. When the branching portion 26a is expanded, the effect of mixing the resin can be expected as such, so that the effect of the resin mixing can be improved with the installation of the partition wall.

The partition wall may be a columnar shape 30 that is spaced apart from both sides of the branching portion 26a to connect the upper and lower sides as shown in FIG. 4A, but as shown in FIG. 4B. It consists of the 1st partition 31 extended from the lower inner wall of 26a, and the 2nd partition 32 extended from the upper inner wall, The edge part of the 1st partition 31 and the end of the 2nd partition 32 are The shape may be spaced apart from each other by a predetermined interval.

In the case of having the shape shown in (b) of FIG. 4, the effect of mixing the resin may be somewhat reduced than in the case of having the shape shown in (a), but the space through which the resin can flow becomes somewhat wider, There is an advantage that can provide a smooth flow.

In addition, the shape of the partition wall can be changed in various ways depending on the design needs.

On the other hand, when the partitions 30, 31, 32 are demonstrated with reference to FIG. 3, it is good to interpose adjacent the edge part of 2nd a runner 22a so that resin mixing can fully exhibit an effect. This is to allow the resin to sufficiently mix with each other in the branch portion 26a after passing through the partition walls 30, 31, and 32.

5 is a simulation result of the injection molding uniform filling apparatus shown in FIG. (A) of FIG. 5 is a finite element model modeling the runner of the injection molding uniform filling apparatus shown in FIG. 3, (b) is data representing a temperature distribution according to (a) model, and (c) is the arrival speed. Data to represent.

As can be seen through (b) and (c) of FIG. 5, according to the present embodiment, it is possible to supply a resin having a uniform temperature distribution to each runner, thereby providing a uniform speed to each runner. Resin can be supplied. In other words, it enables uniform filling.

Next, the operation of the injection molding uniform filling apparatus according to the present embodiment will be described.

When the resin supplied through the hopper 10 flows through the first runner 21, a temperature difference occurs between the resin flowing through the central portion of the first runner 21 and the resin flowing through the side portion. Thereafter, the first runner 21 branches from the first branch portion 25 to the second a runner 22a and the second b runner 22b, whereby the resin also branches (first branch). As the resin flows along the second a runner 22a while passing through the first branch, the temperature difference becomes more severe depending on the position.

 The second a runner 22a branches from the second a branch 26a to the third a runner 23a and the third b runner 23b (secondary branch), and is interposed in the second a branch 26a prior to the branching. By the partition 30, the flow of the resin is changed, and mixing occurs.

Through mixing, the temperature difference between the resins according to the positions is reduced, and resins having a uniform temperature distribution flow into the third a runner 23a and the third b runner 23b, respectively, and are interposed at each runner end. It is supplied to the cavity 50.

Since the resin having almost no difference in temperature distribution is supplied to each cavity 50, the time required for supplying the resin to each cavity 50 also has little difference, resulting in uniform filling.

Many embodiments other than those described above are within the scope of the present invention.

As described above, the injection molding uniform filling apparatus according to the preferred embodiment of the present invention extends the branch portion and installs a partition wall so that a temperature distribution difference does not occur between resins flowing through the branched runner so that uniformity in each cavity is achieved. One filling can be possible.

Claims (8)

An injection molding uniform filling device for supplying resin to a plurality of cavities, A first runner; A branch formed at an end of the first runner; A plurality of second runners branched from the branch portions; And Injection molding uniform filling device including a partition wall interposed in the branch so that the flow of the resin changes. The method of claim 1, The branching portion, Injection molding uniform filling apparatus, characterized in that having a larger cross-sectional area than the first runner. The method of claim 1, The partition wall, Injection molding uniform filling apparatus, characterized in that extending from one inner wall of the branch portion to contact the other inner wall facing the one inner wall to separate the flow of the resin in both directions. The method of claim 1, The partition wall, A first partition wall extending from one side inner wall of the branch part, It includes a second partition wall extending from the other inner wall facing the one inner wall, Injection molding device, characterized in that the end of the first partition and the end of the second partition wall is spaced apart from each other. The method of claim 1, The partition wall, Injection molding uniform filling device, characterized in that interposed adjacent to the end of the first runner. An injection molding uniform filling device for supplying resin to a plurality of cavities, A first runner; A first branch formed at an end of the first runner; A second a runner 22a and a second b runner branched from the first branch part; A second a branch formed at an end of the second a runner; A third a runner and a third b runner branched from the second a branch; A second b branch formed at an end of the second b runner; A third c runner and a third d runner branched from the second b branching part; And Injection molding uniform filling apparatus including a partition interposed at least one of the second branch or the second branch 2b so that the flow of the resin changes. The method of claim 6, The partition wall, Injection uniformly filling device, characterized in that extending from one side inner wall of the 2a branch or the 2b branch portion to contact the other inner wall facing the one inner wall to separate the flow of the resin in both directions. The method of claim 6, The partition wall, A first partition wall extending from one inner wall of the second a branch part or the second b branch part; It includes a second partition wall extending from the other inner wall facing the one inner wall, Injection molding device, characterized in that the end of the first partition and the end of the second partition wall is spaced apart from each other.

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