JP5136191B2 - Powder molding machine and its operating method - Google Patents

Description

The present invention relates to a powder molding machine and a method for operating the powder molding machine, in which powder raw materials such as ceramics and chemicals are filled in a powder molding space (cavity) formed by a die and upper and lower punches.

FIG. 3 shows a method for operating a known powder molding machine. FIG. 3 shows a case where molding is performed with only one axis. An upper punch 81 and a lower punch 82 are inserted into a die 80, and a cavity 83 is formed between them. With the powder raw material being charged into the cavity 83 as shown in (a), the lower punch 82 is raised to the forming completion position as shown in (b), and the powder raw material is pressed. Next, the upper punch 81 is retracted upward as shown in (c), the lower punch 82 is retracted downward (decompression), and finally the lower punch 82 is raised as shown in (d), thereby forming the molded body. 84 is removed from the cavity 83 (demolding).

In the case of the powder molding machine as shown in FIG. 3, since molding is performed with only one shaft, sufficient pressure cannot be obtained and the pressure density of the molded body 84 tends to be insufficient. In order to increase the pressurizing force, the driving force of the driving source (driving motor or fluid pressure cylinder) for operating the upper and lower punches 81 and 82 may be increased. However, this increases the size of the equipment and increases the cost. Become.

On the other hand, there is also a multi-axis press type powder molding machine as shown in Patent Document 1. In this powder molding machine, the lower punch is divided into a cylindrical first lower punch 85 and a second lower punch 86 inserted therein, as shown in FIG. 2 The lower punch 86 is driven by a separate drive source. In this case, as shown in FIG. 4B, both the lower punches 85 and 86 are operated by separate driving sources, so that the pressing force per unit area of the molded body 84 can be increased, and the compact size can be reduced. A compact having a high pressure density can be obtained while using the above drive source. In FIG. 4, only the lower punch has a split punch structure, but the upper punch may have a similar split punch structure.

However, in the case of the powder molding machine having the structure as shown in FIG. 4, there is a gap δ (see FIG. 5) between the first lower punch 85 and the second lower punch 86. There is a problem that burrs inevitably occur on the surface of 84. Further, in order to obtain a molded body 84 having a flat surface, it is necessary to eliminate the step difference between the upper surface positions of the first lower punch 85 and the second lower punch 86, so that the load applied to both the punches 85 and 86 is equally divided. Equipment is required, resulting in high costs.
JP 2002-172498 A

An object of the present invention is to propose a powder molding machine capable of obtaining a compact having a high pressure density while using a small driving source and capable of forming a compact having no burrs or steps on the surface, and an operating method thereof. To do.

In order to achieve the above object, the invention according to claim 1 is characterized in that a cavity is formed by a die and a lower punch arranged so as to face each other with the die sandwiched therebetween, and one of the upper and lower punches is operated. In the powder molding machine that press-molds the powder raw material charged into the cavity, the main drive means capable of operating the one punch beyond the molding completion position as a target position; and Provided is a support block capable of contacting the back of one punch, and a sub-driving means for operating the support block so that the support block can reach the molding completion position by pushing behind the one punch in operation. A powder molding machine is provided.

According to a third aspect of the present invention, a cavity is formed by a die and a lower punch which are arranged so as to face each other with the die interposed therebetween, and either one of the upper and lower punches is operated to move the cavity into the cavity. In the operation method of the powder molding machine for pressure-molding the charged powder raw material, the one punch is operated with the position beyond the molding completion position as a target position, and a predetermined pressure limit value is reached by the punch. The first step of pressurizing the powder raw material until the pressure limit value is reached, and the punch is pressed behind the support block while continuing to operate the punch, and the resultant force of the punch and the support block A second step of pressurizing the raw material; and a third step of releasing the pressing force by the support block when the support block reaches the molding completion position; Providing Releasing serial support block and a fourth step of releasing the pressure applied by the punch simultaneously or subsequently, a method of operating a powder molding machine, comprising the.

The present invention is applied when a method using only one axis of a powder molding machine lacks output, or when a method using a plurality of divided punches causes quality abnormalities such as burrs and steps. First, one of the upper and lower punches is actuated by the main drive means, whereby the powder raw material charged into the cavity is pressure-molded. However, since a desired pressing force cannot be obtained only by operating the punch by the main drive means, a support block is arranged behind the punch, and this support block is operated by a sub drive means different from the punch. That is, molding is performed with both resultant forces by assisting the output of the punch with the output of the support block. As a result, a compact having a high pressure density can be obtained by making full use of the outputs of these drive means while using relatively small drive sources as the main and secondary drive means. Moreover, since a split punch is not used to pressurize the powder raw material, it is possible to prevent burrs and steps from being generated on the surface of the molded body. Since the molding completion position can be defined by the position of the support block, the dimensions of the final molded body can be managed with high accuracy.

When the punch is stopped or when the original forming completion position is set to the target value of the punch, when the support block is pressed from the rear, the punch performs the positioning operation while changing the output direction by the drive means (for example, servo motor). Therefore, it will press against the support block, and a resultant force cannot be generated. In the worst case, it leads to equipment damage. In the present invention, the target position of the punch is set to a position beyond the molding completion position necessary for molding, and the output is always generated in the traveling direction, so that the resultant force is generated without pressing against the support block supported from the rear. It becomes possible. In this way, from the time when the support block contacts the back of the punch until the punch is pushed by the support block and reaches the molding completion position, it is in front of the target position of the punch. Can be pressed against each other.

During pressure molding, the powder raw material is pressurized with one punch until it reaches the specified pressure limit, and after reaching the pressure limit, the back of the punch is pressed with the support block while continuing to operate this punch. It is preferable to pressurize the powder raw material. In this case, since the support block assists after one of the punches is operated to the pressure limit value, the outputs of the punch and the support block can be appropriately combined, and load control is facilitated. The method for setting the pressure limit value can be set by a torque limiter when, for example, a servo motor is used as the driving means, and can be set by the fluid pressure when a fluid pressure cylinder is used.

As described above, according to the present invention, the support block operated by the sub-driving unit is provided behind the punch operated by the main driving unit, and the support block pushes the punch being operated to the molding completion position. Since it did it, it can shape | mold by the resultant force of both a punch and a support block. Therefore, while using relatively small driving sources as the main and sub driving means, the output of these driving means can be fully utilized to obtain a compact with high pressure density. Moreover, since a split punch is not used to pressurize the powder raw material, it is possible to prevent burrs and steps from being generated on the surface of the molded body. Since the molding completion position can be defined by the position of the support block, the final molded body dimensions can be managed with high accuracy.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic configuration diagram of a powder molding machine according to an embodiment of the present invention. This powder molding machine 1 manufactures a ceramic electronic component element by press-molding a ceramic powder raw material. The powder molding machine 1 includes a cylindrical die 10 and an upper punch unit 20 and a lower punch unit 30 that are opposed to each other with the die 10 interposed therebetween. The part surrounded by is a cavity 11 for powder molding.

The die 10 is held by a die support plate 12, and a plurality of cylindrical drive shafts 13 are connected and fixed to the periphery of the die support plate 12. A ball screw 14 is inserted into the drive shaft 13, and a nut 15 that is screwed with the ball screw 14 is attached to the lower end portion of the drive shaft 13. Therefore, when the ball screw 14 is rotated, the drive shaft 13 moves up and down, and the die 10 moves up and down via the die support plate 12 accordingly. The die support plate 12 is provided with a scale 16 for detecting the height position.

The upper punch unit 20 includes an upper ram 21 and an upper punch 22 fixed to the lower surface thereof. The upper ram 21 is fixed to the base 24 via a plurality of support columns 23. Therefore, the upper punch 22 is fixed at a certain position. A raw material hopper 25 is provided at the upper portion of the upper ram 21, and the powder raw material discharged from the raw material hopper 25 is supplied to a raw material supply unit 26 disposed on the die support plate 12. The raw material supply unit 26 can slide on the die support plate 12 by the raw material supply driving unit 27 and put the raw material into the cavity 11.

The lower punch unit 30 is inserted into a lower punch 31 inserted into the cavity 11 of the die 10, a lower punch support plate 32 that supports the lower surface of the lower punch 31, and a through hole 33 provided in the lower punch support plate 32. And a support block 40 that can contact the lower surface of the lower punch 31. A plurality of cylindrical drive shafts 34 are connected and fixed to the lower punch support plate 32. A ball screw 35 is inserted into these drive shafts 34, and a nut 36 that is screwed into the ball screw 35 is attached to the lower end portion of the drive shaft 34. Therefore, when the ball screw 35 is rotated, the drive shaft 34 moves up and down, and accordingly, the lower punch 31 moves up and down via the lower punch support plate 32. A scale 37 for detecting the height position is attached to the lower punch support plate 32. This scale 37 is provided as necessary.

A cylindrical drive shaft 41 is connected and fixed to the support block 40, and a ball screw 42 is inserted into the drive shaft 41, and a nut 43 that is screwed with the ball screw 42 at the lower end of the drive shaft 41. Is installed. Therefore, by rotating the ball screw 42, the drive shaft 41 moves up and down, and the support block 40 moves up and down accordingly. A scale 44 for detecting the height position of the support block 40 is attached.

A ball screw 14 that moves the die support plate 12 up and down, a ball screw 35 that moves the lower punch support plate 32 up and down, and a ball screw 42 that moves the support block 40 up and down are bearings 50, 51, fixed to the base 24. 52 is rotatably supported. Pulleys 53, 54, and 55 are attached to end portions of the ball screws 14, 35, and 42 that protrude to the lower surface side of the base 24. A timing belt 58 is wound between a pulley 53 connected to the ball screw 14 and a pulley 57 attached to a rotary shaft of a die drive servo motor 56 installed on the base 24. Similarly, there is a timing between the pulley 54 connected to the ball screw 35 and the pulley 60 attached to the rotary shaft of the lower punch driving servomotor (main driving means) 59 installed on the base 24. A belt 61 is wound around. Further, there is a timing belt between a pulley 55 connected to the ball screw 42 and a pulley 63 attached to a rotating shaft of a support block driving servomotor (sub driving means) 62 installed on the base 24. 64 is wound. In this embodiment, the lower punch driving servomotor 59 is provided with a torque limiter that regulates the driving torque to a limit value (for example, 100 kN · m) lower than the torque required for powder molding. The drive torque of the support block drive servomotor 62 is set to 150 kN · m, for example, but the drive torque may be equal to or lower than the drive torque of the lower punch drive servomotor 59.

Position signals are input to the control device 70 from the scale 16 provided on the die support plate 12, the scale 37 provided on the lower punch support plate 32, and the scale 44 provided on the support block 40, respectively. The die drive servo motor 56, the lower punch drive servo motor 59, the support block drive servo motor 62, and the raw material supply drive unit 27 are controlled in accordance with these signals.

Here, a method for producing a molded body using the powder molding machine 1 having the above-described configuration will be described with reference to FIG. FIG. 2 illustrates the forming stage, the positions of the lower punch 31 and the support block 40, and the output thereof. First, the height of the die 10 is adjusted by the die drive servo motor 56, the raw material supply unit 26 is moved to the upper surface of the cavity 11 with the lower punch 31 inserted into the cavity 11, and the lower punch 31 is lowered. The raw material is supplied to the cavity 11. After supplying the raw material, the die 10 and the lower punch 31 are raised together, and the upper punch 22 is inserted into the cavity 11 to complete the preparation ((a) of FIG. 2).

Next, the lower punch 31 is raised by the lower punch drive servomotor 59 with the position above the molding completion position necessary for the original molding as a target position. At this time, since the lower punch driving servomotor 59 is provided with a torque limiter (100 kN · m), torque limitation is applied before reaching the molding completion position, and the lower punch driving servomotor 59 cannot be raised (( b)).

After the lower punch 31 can no longer be raised in a state where the torque is restricted, the support block 40 starts to rise ((c) in FIG. 2). Until the support block 40 contacts the lower punch 31, the drive torque of the support block 40 is low.

Eventually, when the support block 40 comes into contact with the lower punch 31, the lower punch 31 is pushed up by the support block 40 and rises together. At this time, since the lower punch 31 has not reached the target position, an upward output (100 kN · m) continues to be generated, and a downward pressure (pressure in the direction of pressing against the support block 40) does not occur. . The pressure applied to the raw material powder of the lower punch 31 is a resultant force of the driving force of the lower punch driving servomotor 59 and the driving force of the support block driving servomotor 62, so that the raw material powder can be molded to a desired pressure density ( (D) of FIG. In this embodiment, since the output of the lower punch 31 is 100 kN · m and the output of the support block 40 is 150 kN · m, the raw material powder can be formed with a pressing force of 250 kN · m. The support block 40 is provided with a scale 44. When the scale 44 detects the molding completion position, the drive of the support block driving servo motor 62 and the lower punch driving servo motor 59 is stopped.

After the molding is completed, the support block 40 is first released ((e) in FIG. 2), and the lower punch 31 is released after a delay ((f) in FIG. 2). Thereafter, by lowering the die 10 relative to the lower punch 31, the molded body is pushed up by the lower punch 31 and taken out from the cavity 11.

Even with a multi-axis powder molding machine that does not have a maximum output of 150 kN · m for a compact that requires a pressing force of 250 kN · m as described above, the lower punch 31 and the support block 40 are provided. Molding is possible with proper operation.

In the above embodiment, the servo motor and the ball screw mechanism are used as the driving means for the lower punch 31 and the support block 40, but a fluid pressure cylinder may be used. In particular, when a fluid pressure cylinder is used as a driving means for the lower punch that performs load control, the predetermined torque limit value can be set by the fluid pressure, so that the control is simplified.
Moreover, although the example which fixes the upper punch 22 and raises / lowers the die | dye 10 was shown in FIG. 1, the die | dye 10 may be fixed to fixed height and the upper punch 22 may be raised / lowered.
Further, the upper and lower punches may be arranged in reverse. That is, even if the lower punch is fixed, the support block is disposed above the upper punch, and the support block is pushed from behind the upper punch, the same effect as the above embodiment can be achieved.

It is the schematic which shows the structure of the powder molding machine which concerns on this invention. It is a figure which shows the action | operation of the powder molding machine shown in FIG. 1, and is a figure which shows the relationship between a punch position and an output. It is operation | movement explanatory drawing of an example of the conventional powder molding machine. It is operation | movement explanatory drawing of the other example of the conventional powder molding machine. It is a principal part enlarged view in the powder molding machine of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Powder molding machine 10 Dice 11 Cavity 12 Die support plates 13, 34, 41 Drive shafts 14, 35, 42 Ball screw 16, 37, 44 Position detection scale 20 Upper punch unit 21 Upper ram 22 Upper punch 24 Base 25 Raw material hopper 27 Raw material supply drive unit 30 Lower punch unit 31 Lower punch 32 Lower punch support plate 40 Support blocks 53, 54, 55, 57, 60, 63 Pulleys 58, 61, 64 Timing belt 56 Dies driving servo motor 59 Lower punch Servo motor for driving (main driving means)
62 Support block drive servo motor (sub drive means)

Claims (4)

A cavity is formed with the lower punch and the die placed so as to face each other across the die, and either one of the upper and lower punches is operated to pressurize the powder raw material charged into the cavity. In the powder molding machine to mold,
A main drive means capable of operating as a target position a position beyond the molding completion position of the one punch;
A support block that can be contacted behind the one punch;
A powder molding machine, comprising: a sub-driving means for actuating the support block so that the support block can be pushed behind the one punch in operation to reach a molding completion position. The powder molding machine according to claim 1, further comprising a detection unit configured to detect that the support block has reached a molding completion position. The main driving means is provided with a pressing force limiting means for limiting the pressing force of the one punch to a value or less necessary for compressing the powder raw material to a predetermined pressure density. Item 3. A powder molding machine according to Item 1 or 2. A cavity is formed with the lower punch and the die placed so as to face each other across the die, and either one of the upper and lower punches is operated to pressurize the powder raw material charged into the cavity. In the operation method of the powder molding machine to form,
A first step of operating the one punch beyond the molding completion position as a target position and pressurizing the powder raw material until the predetermined pressure limit value is reached by the punch; and
A second step of pressing the back of the punch with a support block while continuing to operate the punch after reaching the pressure limit value, and pressurizing the powder raw material by the resultant force of the punch and the support block;
A third step of releasing the pressing force by the support block when the support block reaches the molding completion position;
And a fourth step of releasing the pressure applied by the punch simultaneously with or after the release of the support block.

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