JP4789259B2 - Raw material bead filling method - Google Patents

Description

  The present invention relates to a method for filling raw material beads in a foamed resin molding machine.

  As a foamed resin molding machine, for example, a drive cylinder system disclosed in Patent Document 1 and a ball screw system disclosed in Patent Document 2 are known. The foam molding method using such a foamed resin molding machine is as follows: (1) A step of filling raw material beads in which a mold is closed to form a cavity, and raw material beads such as polystyrene are filled in the cavity. (2) A heating process in which the raw material beads are heated with steam for heating to melt and foam, (3) a cooling process in which the foam is then cooled and solidified, and (4) a mold is opened after cooling to form a foam having a predetermined shape. A mold release step to be removed from the mold.

As a method for filling raw material beads, there is a cracking filling method. In this method, as shown in FIG. 7, the fixed mold 3 and the movable mold 4 are not completely closed during the filling operation, and a certain gap, that is, a cracking gap 51 is left in the outer periphery of the mold. This is a method in which injection air for feeding is supplied to the raw material supply machine 50, and the raw material beads are sucked in by the jet power and are fed into the cavity 60 for filling. The injection air itself is discharged outside through the cracking gap 51.
In addition, there exists a thing disclosed by patent document 3 as a raw material supply machine.

  In the cracking filling method as described above, in the mold fitting portion 61 in the vicinity of the cracking gap 51, this portion is far from the raw material supply machine 50, or the bridging of the raw material beads due to static electricity or the like causes insufficient filling density. Prone to occur.

In addition, after the material beads are filled in the cavity 60, the cracking gap 51 is completely closed and the mold is closed. Therefore, in particular, the central portion 63 of the cavity 60 close to the raw material feeder 50 and the intermediate portion 62 between the mold fitting portion 61 and the central portion 63 are overfilled by the cracking gap S as shown in FIG. As a result, the packing density becomes excessively high. Such a portion with a high packing density requires a longer time for cooling than a portion with a low filling density, resulting in a decrease in production efficiency.
JP-A-5-154930 (FIG. 1) JP-A-5-193014 (Fig. 1) Japanese Patent Laid-Open No. 2000-15707 (FIG. 1)

  In view of the above-described conventional problems, it is an object of the present invention to provide a raw material bead filling method capable of uniformly filling raw material beads in a cavity and shortening the cooling time. To do.

The raw material bead filling method of the present invention made to solve the above problems is a raw material bead filling method in which raw material beads are filled with injection air into a cavity formed by a fixed mold and a movable mold.
As a method of moving the movable type with a ball screw,
When this movable mold is moved and positioned at the filling start cracking position, the filling of the raw material beads is started,
Thereafter, the ball screw is rotated continuously or intermittently, and the raw material beads are filled into the cavity while narrowing the cracking gap in a stepless manner or in multiple steps.

In the above-described invention, when the movable mold is moved and positioned at the filling start cracking position, the first step of filling the raw material beads into the mold fitting portion of the cavity;
A second step of narrowing the cracking gap one step and filling the middle part of the cavity with raw material beads;
A third step of further narrowing the cracking gap and filling the central part of the cavity with raw material beads;
The raw material beads can be filled in a multi-stage process including the fourth process of closing the cracking gap and completing the mold closing.

  In addition, while filling the material beads in the cavity while narrowing the cracking gap, by reversing the ball screw and expanding the cracking gap at least once, by rotating the ball screw forward again and reducing the cracking gap, The raw material beads in the cavity can be filled with the raw material beads by applying pulsation due to expansion and compression of air.

  Further, after the second step is completed, the first step is returned to the first step at least once, and the first step and the second step are repeated a plurality of times. The raw material beads can be filled by applying pulsation due to compression.

  According to the first aspect of the present invention, since the ball screw is continuously or intermittently rotated to fill the raw material beads into the cavity while narrowing the cracking gap steplessly or in multiple steps, the mold corresponding to the cracking gap after filling the raw material. There is no need to close. Therefore, the material beads are not excessively filled in the cavity.

  In the invention according to claim 2, since the raw material beads are filled in the cavity while narrowing the cracking gap in four stages, the raw material beads are not excessively filled.

  The inventions according to claims 3 and 4 can impart pulsation due to expansion / compression of air to the raw material beads in the cavity. Therefore, even when a bridge of the raw material beads is formed in the cavity, these are pulsated by air. And can be filled uniformly with the raw material beads.

The present invention will be described below with reference to the drawings.
1 and 2 show a ball screw type foamed resin molding machine for carrying out the method of the present invention. In the figure, a movable die plate 2 is disposed opposite to the fixed die plate 1. Each die plate 1, 2 has a fixed mold 3 and a movable mold 4. In the center of the fixed mold 3, a raw material supply machine 50 for sending raw material beads by injection air is disposed. In addition, two ball screws 5 and 6 are mounted via nuts 7 at positions facing each other across the movable die 4.

  A high-speed moving mechanism 8 of the moving die plate 2 is disposed at the end of one ball screw 5, and a low-speed moving mechanism 9 of the moving die plate 2 is disposed at the end of the other ball screw 6. Yes. Between these ball screws 5 and 6, a power transmission member 11, such as a belt or a chain, for transmitting the rotation of one ball screw 5 or 6 to the other is interposed.

  The high-speed moving mechanism 8 includes a motor 13 in which a motor shaft 12 is directly connected to the ball screw 5. The high speed moving mechanism is used when the movable die 4 is moved to the cracking position at the time of filling the raw material, or when the movable die 4 is moved backward from the release cracking position in order to take out the molded product after the release.

  The low-speed moving mechanism 9 is used when the mold is closed, and includes a motor 21, a speed reducer 22 connected to the motor 21, and a gear 24 that transmits the rotation of the speed reducer 22 to the ball screw 6. That is, the rotation of the motor 21 is decelerated by the speed reducer 22 to rotate the gear 24, whereby the ball screw 6 can be rotated at a low speed. The reduction gear 22 and the gear 24 can be engaged and disengaged by air. Further, the rotation of the motor 21 is increased or decreased as necessary.

  In the configuration as described above, when the movable die plate 2 is moved to the filling start cracking position, the motor 13 of the high speed moving mechanism 8 is driven to rotate the ball screws 5 and 6 at high speed. As a result, the movable die 4 can be moved in the direction of the fixed die 3 at a high speed and can be positioned at the filling start cracking position.

  Thereafter, when closing the mold by narrowing the cracking gap, the motor 13 is stopped and the motor 21 of the low speed moving mechanism 9 is driven. As a result, the movable mold 4 can be brought close to the fixed mold 3 at a low speed to narrow the cracking gap, and the mold can be closed with a high clamping force.

  FIG. 3 shows a control system in the foam molding machine. In the figure, a timer 52 is connected to the raw material filling machine 50, and this timer 52 is connected to a controller 53. On the other hand, the motor 21 is provided with a movable type 4 position detecting means 54 such as a rotary encoder, and the position detecting means 54 is connected to a controller 53. 51 is a cracking gap.

Below, the filling method of the raw material beads which narrows the cracking gap | interval 51 in a stepless manner is demonstrated based on FIGS.
When the movable die 4 is positioned at the filling start cracking position, the raw material beads are sucked by blowing in the injection air, and the raw material beads are fed into the cavity 60. As a result, first, the raw material beads are filled in the mold fitting portion 61 (FIG. 4). Then, corresponding to the progress of filling, the ball screw is rotated at a low speed to narrow the cracking gap 51, and the intermediate portion 62 and the central portion 63 are filled with the raw material beads (FIGS. 5 and 6). When the center part 63 is filled with a predetermined amount of raw material beads, the cracking gap 51 is completely closed to complete the mold closing. Thereafter, the raw material beads are fed as necessary, and particularly the filling amount in the vicinity of the central portion 63 is secured to complete the filling.

  The above filling method is implemented as follows. That is, the timer 52 shown in FIG. 3 starts counting when the raw material beads are supplied. As the count progresses, the controller 53 drives the motor 21 and accurately grasps the position of the movable die 4 from the signal from the position detecting means 54. The rotational speed of the motor 21 can be adjusted as appropriate.

  Then, the raw material beads are filled while narrowing the cracking gap 51. At the timing when the central portion 63 is appropriately filled by the count of the timer 52, the cracking gap 51 is closed by a command from the controller 53 to complete the mold closing. After the mold is closed, the raw material beads are further filled as necessary, and the feeding of the raw material beads is stopped by the count-out of the timer 52.

  In the above process, the cracking gap 51 can be expanded at least once by reversing the ball screw while filling the raw material beads in the cavity 60 while narrowing the cracking gap 51 steplessly. In order to prevent wasteful consumption due to spattering of raw material beads, it is necessary that the cracking gap 51 does not exceed the cracking gap S at the start of filling. By repeating expansion and contraction of the cracking gap 51 many times, even when a bridge made of raw material beads is formed, these can be broken by giving pulsation and vibration due to expansion and compression of air. Therefore, by subsequently rotating the ball screw forward, it is possible to uniformly fill the raw material beads into the cavity 60 while narrowing the cracking gap 51 steplessly. The raw material beads can be filled more uniformly by shaking the injection air at high and low pressures.

Moreover, the filling of the raw material beads can be performed even when the cracking gap is narrowed in multiple stages by intermittently rotating the ball screw.
That is, in the first step, when the movable mold 4 is located at the filling start cracking position, the raw material beads are fed into the cavity 60 and the raw material beads are filled into the mold fitting portion 61 (FIG. 4).

  In the second step, the movable die 4 is moved to narrow the cracking gap 51 by one step, and then the intermediate part 62 is filled with the raw material beads (FIG. 5). The raw material beads are also fed in the middle of narrowing the cracking gap 51.

  In the third step, the movable die 4 is moved to further narrow the cracking gap 51 by one step, and then the raw material beads are appropriately filled in the central portion 62 (FIG. 6).

  Further, in the fourth step, the cracking gap 51 is closed to complete the mold closing. And when the filling of the center part 62 is not enough, the raw material beads are further fed to secure the filling amount.

  The filling method comprising the above four steps can be carried out as follows. That is, the timer 52 shown in FIG. 3 starts counting when the raw material beads are supplied. As the count of the filling of the mold fitting portion 61 is completed, the controller 53 drives the motor 21 to narrow the cracking gap 51 by one step. When the counting proceeds until the filling of the intermediate portion 62 is completed, the controller 53 re-drives the motor 21 to further narrow the cracking gap 51. The mold closing is completed at a timing when a predetermined amount of raw material beads are filled in the central portion 63. After the mold is closed, the raw material beads that are further insufficient are filled as necessary, and the filling of the raw material beads is finished by counting out the timer 52.

  A fishing box having a wall thickness of 20 mm was formed by foaming resin molding with a filling bead cracking gap S of 5 mm by the raw material bead filling method comprising the above four steps. As a result, overfilling of the intermediate part 62 and the central part 63 could be prevented, and the cooling time after molding could be shortened by 20%.

  In the above-described invention, the first step and the second step can be repeated a plurality of times by returning to the first step at least once after the end of the second step. By repeatedly expanding and reducing the cracking gap in this manner, the raw material beads can be pulsated and vibrated by the expansion and compression of the air in the cavity, and the bridges are broken and the mold fitting part 61 and the intermediate part 62 are broken. Can be uniformly filled with raw material beads.

  As described above, the method of the present invention is characterized in that the raw material beads are filled while performing mold closing continuously or intermittently. That is, since the filling is completed at the same time as the mold closing is completed, or the shortage is replenished after the mold closing is completed, the mold closing is not performed after the raw material beads are filled. Therefore, overfilling associated with mold closing does not occur. Further, since the cracking gap is enlarged and reduced during the filling, there is a great advantage that the raw material beads can be uniformly filled by breaking the bridge by the pulsation of air.

It is a top view of the foam molding machine for implementing this invention. It is a front view of the foam molding machine of FIG. It is a schematic block diagram of the foam molding machine which also shows a control system. It is explanatory drawing which shows the state with which the type | mold fitting part was filled with the raw material bead. It is explanatory drawing which shows the state by which the raw material bead was filled also in the intermediate part. It is explanatory drawing which shows the state by which the raw material bead was filled also in the center part. It is explanatory drawing which shows the state before mold closing in the conventional method. It is explanatory drawing which shows the state after the mold closing in the conventional method.

Explanation of symbols

  3 fixed type, 4 moving type, 51 cracking gap, 60 cavities

Claims (4)

In the raw material bead filling method of filling the raw material beads with injection air into the cavity formed by the fixed mold and the movable mold,
As a method of moving the movable type with a ball screw,
When this movable mold is moved and positioned at the filling start cracking position, the filling of the raw material beads is started,
Then, the ball screw is rotated continuously or intermittently, and the raw material beads are filled into the cavity while narrowing the cracking gap in a stepless manner or in multiple steps. A first step of filling the raw material beads into the mold fitting portion of the cavity when the movable mold is moved and positioned at the filling start cracking position;
A second step of narrowing the cracking gap one step and filling the middle part of the cavity with raw material beads;
A third step of further narrowing the cracking gap and filling the central part of the cavity with raw material beads;
The raw material bead filling method according to claim 1, wherein the raw material beads are filled in a multi-stage process of closing the cracking gap and completing the mold closing.   While filling the beads with the raw material beads while narrowing the cracking gap, the ball screw is reversed at least once to enlarge the cracking gap, and then the ball screw is rotated forward again to reduce the cracking gap. 2. The raw material bead filling method according to claim 1, wherein the raw material beads are filled with pulsation caused by expansion / compression of air. Return to the first step at least once after the end of the second step, repeat the first step and the second step a plurality of times, and expand and contract the cracking gap, thereby expanding and compressing the raw material beads in the cavity. 3. The raw material bead filling method according to claim 2, wherein the raw material beads are filled with pulsation.

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