JP2662910B2 - Vibration compression molding machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a press-type powder molding machine for compressing and molding powders of various metals and ceramics in a molding space formed by a die and a punch.

[0002]

2. Description of the Related Art In compression molding in which a metal or other powder is compacted and compacted, the density of the compacted powder filled in the compacting space and the density distribution of the compacted powder at the time of compaction are determined by the strength of the compact, which is a compact. It has a significant effect. It is known that adding vibration during filling or compression of the molding powder is effective in improving the powder density during filling and making the density distribution uniform during compression. For this reason, there is a type in which a vibrator is attached to a base of a die plate or a punch. However, the method of applying vibration from the outside like a vibrator has an adverse effect on mechanical contact points such as the sliding surface of the die and the punch, and the molding space itself is also vibrating. However, there is a disadvantage in that the effect of the vibration is not direct and the efficiency is low. Also, when using a multi-stage compression molding machine in which the punch is divided into a plurality of parts, although partial compression is possible,
Vibration cannot be partially applied.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a compression molding machine in which vibrations to a molding powder are added directly from a punch.

[0004]

A punch for compressing a molding powder is provided. The punch is moved by a drive mechanism driven by a servomotor. A control device for the servomotor and a vibration adding means for adding a vibration with a small amplitude to the drive of the servomotor are provided.

[0005]

The servo motor moves the punch based on the machining program and setting data input to the control device. The vibration adding means adds a vibration element to the drive of the servomotor.

[0006]

FIG. 1 shows a vertical vibration compression molding machine 1 (hereinafter simply referred to as a molding machine) having a die 2, an upper punch 3, and a lower punch 4 in a central portion, and a punch moving mechanism 5 comprising an upper punch. 3
, A crank mechanism 6 and an upper screw nut mechanism 7 having a booster structure, and a lower screw nut mechanism 8 is used for the lower punch 4. Each of the screw nut mechanisms 7 and 8 is composed of a ball screw 9 and a ball nut 10 screwed thereto. The die 2 is exchangeably supported at the center of a die plate 12 supported by a base 11, and has a vertically penetrated hole. A feeder 13 for supplying molding powder is disposed on the upper surface of the die plate 12 and is reciprocally movable from a home position shown in FIG. The base 11 has two parallel guide bars 14,
14 stands upright through the die plate 12, and is connected at the upper end by an upper machine frame 15. Then, between the upper machine frame 15 and the base 11, the middle machine frame 1 is positioned from above.
6. The upper movable machine frame 17 and the lower movable machine frame 18 are arranged horizontally and slidably mounted on the guide bars 14 and 14, respectively.

The upper machine frame 15 and the middle machine frame 16 are connected by a crank type moving mechanism 6, and the mechanism 6 is driven by a link drive servomotor 19 mounted on the upper machine frame 15.
The middle machine frame 16 and the upper movable machine frame 17 are connected by an upper screw nut mechanism 7, and this mechanism 7 is configured such that the ball nut 10 is
The upper movable frame 17 is moved up and down with respect to the middle frame 16 by being driven by the servomotor S1 attached to 6. The upper punch 3 is fixed to the lower surface of the upper movable machine frame 17 via a pressure sensor 20 at its base. The lower machine frame 18 is connected to the base 11 by the lower screw nut mechanism 8, and the ball nut 10 is driven by a servomotor S2 fixed to the base 11 to move up and down. The lower punch 4 is fixed to the upper surface of the lower machine frame 18 via a pressure sensor 21. Each of the servo motors S1 and S2 has a brake.

The drive-side shaft 22, the driven-side shaft 23, the upper punch 3, the lower punch 4, and the die 2 of the crank type moving mechanism 6
It is arranged coaxially along one compression axis a set in the longitudinal direction at substantially the center of the molding machine 1. The upper punch 3 and the lower punch 4 can face the punch surfaces in the hole of the die 2. I can do it. Further, the link drive servomotor 19, the servomotors S1, S2 and the feeder 8
Is connected to the servo amplifier of the control device 24, and the detection outputs of the pressure sensors 20 and 21 are connected to the computer built-in numerical controller (CNC) of the control device 24.

The control device 24 operates a machining program input to the RAM in accordance with a system program stored in the ROM in a usual manner, and sets data or pressure sensors 20 and 21 input from a manual input device (MDI).
The servo motors S1 and S2 for moving the link drive servomotor 19, the upper movable machine frame 17, and the lower movable machine frame 18 are driven on the basis of the detection output from. In addition, an on / off signal is output to the actuator of the feeder 13. The control device 24 is also configured as shown in FIG. 2, and an oscillator 25 is connected to a servo amplifier as vibration adding means. The oscillator 25 generates a vibration voltage A having a constant amplitude of about 5 to 10 Hz. This voltage is superimposed on the movement command signal B for the servo motors S1 and S2 inside the servo amplifier, and the vibration movement command signal C Become.
The movement command signal B is transmitted from the CNC to the servo amplifier. Note that the oscillator 25 has a normal configuration and can arbitrarily adjust the frequency, waveform, and amplitude of the output voltage.

The molding operation by the molding machine 1 is performed as follows. The machining program and data relating to the positions of the upper and lower punches 3 and 4 or data relating to the compressive force are input to the controller 24, and the output waveform shape and output magnitude (amplitude) of the oscillator 25 such as frequency, sine wave and square wave are input. ) Set the output start timing and output time. At the beginning of operation,
The molding machine 1 is at the home position where the upper punch 3 is at the upper limit position and the lower punch 4 is at the home position where the punch surface is aligned with the upper surface of the die plate 12.

When the servo motor S2 is driven, the lower punch 4 is lowered via the screw nut mechanism 8 to form a molding space 26 as shown in FIG. The feeder 13 is reciprocated to the position of the die 2 to fill the molding space 25 with the molding powder. Next, a movement command is issued to the upper punch 3, and the upper punch 3 compresses the powder by an operation according to the signal waveform. At this time, the timer is set to a star at the same time as the movement command signal B, and when the output start timing is reached, the above-mentioned signal waveform is generated by the oscillator 25 for the set output time.
When the upper punch 3 reaches the molding space 26 by adjusting the start time, the upper punch 3 is already vibrating, and the powder in the molding space 26 is compressed. Excited from the beginning, powder density improves,
Also, the density distribution is made uniform. Further, since the output time can be set, unnecessary vibration is not required.

Further, vibration is applied even during compression, and the powder is compressed uniformly and with high density. Vibration is applied by the upper punch 3 efficiently since no vibration is applied to the die 2 and the die 2 is fixed to the upper punch 3. As described above, the upper punch 3 directly applies vibration to the powder. Furthermore, since the shape and frequency of the output vibration waveform can be freely selected, the compression can be performed uniformly regardless of the composition of the powder.

When the compression process is completed, the upper punch 3 returns to the home position to stop the vibration. Then, the lower punch 4 also returns to the above-described home position, and the compact (molded product) in the molding space 26 is removed from the die. It is extruded on the upper surface of the plate 12. In this way, a green compact having a high powder density and a uniform density distribution can be obtained.

In the above embodiment, since the lower screw nut mechanism 8 has the same configuration as the upper screw nut mechanism 7, the servo motor S2 and the screw nut mechanism 8
Vibration can also be applied to the lower punch 4 via.
Therefore, the vibration can be applied at the time of compression by using the first and second punches 3 and 4 individually or simultaneously. The above screw nut mechanism employs a ball screw / nut, but may have other shapes and types such as a triangular screw, a trapezoidal screw, and a roller screw.

The upper and lower screw nut mechanisms 7 and 8 are
Upper and lower movable machine frames 1 by servo motors S1 and S2
The position of 7, 18 can be adjusted up and down and used as a means for determining the position. Thereby, the position of the lower punch 4 is moved up and down to adjust the size of the molded product, or the upper punch 3
Can be adjusted so that the crank mechanism is fully extended (highest boosting efficiency) when compression is completed, even if the dimensions of the molded product are changed. Further, in the compression with the above-described vibration, the difference between the input vibration and the output vibration can be compared using the detection outputs of the pressure sensors 20 and 22, and the input waveform can be adjusted as necessary. Further, feedback control is performed so that this detection output matches the preset compression force, and the output waveform is displayed on a display device (CR).
Since it is possible to monitor by T) or a printed matter by a printer, it is possible to ensure reproducibility and check by eyes.

The above is the embodiment. The vibration adding means may be any means that adds to the control system of the servomotors S1 and S2. As the vibration adding means, a machining program in which data on the positions of the upper and lower punches 3 and 4 is set in the form of small vibrations is used. Can be used. According to this, an oscillator is not required, and the vibration is transmitted directly from the punch to the powder as the processing program is executed.

A vibration adding means may be connected to the control system of the link drive servomotor 19, and the upper and lower screw nut mechanisms 7, 8 may be replaced with another structure such as a link type.

When the punch is a multi-stage composed of a plurality of partial punches, a vibration applying means is provided for each of the partial punches so that the addition of the vibration can be stopped as required.

The frequency and amplitude of the vibration to be added are determined by the mass of a portion that needs to be vibrated by a servomotor (for the servomotor S1, the upper punch 3, the upper movable machine frame 17, the upper screw nut mechanism, etc.) and the molding machine. There is a limit due to the mechanical responsiveness of (1).

[0020]

According to the present invention, vibration can be applied directly to the molding powder by the punch, so that the vibration can be efficiently applied. In the case where the punches are multi-stage, vibration can be applied only to necessary portions.

Since the powder density of the green compact is high and the density distribution is uniform, a molded product having high strength can be obtained.

[Brief description of the drawings]

FIG. 1 is a front view mechanically shown.

FIG. 2 is a mechanism diagram of a control device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Vertical compression molding machine 2 Die 3 Upper punch 4 Lower punch 5 Punch moving mechanism 7 Upper screw nut mechanism 8 Lower screw nut mechanism 12 Die plate 13 Feeder 19 Link drive servomotor 24 Control device 25 Molding space

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takayuki Taira 3580 Kobaba, Oshino-mura, Oshino-mura, Minamitsuru-gun, Yamanashi Pref. 3580 Baba FANUC CORPORATION Product Development Research Center

Claims (1)

(57) [Claims] 1. A servo motor driven punch moving mechanism, and a control system of the servo motor controlled by a control device is provided with vibration adding means for adding a vibration of a small amplitude to the drive of the servo motor. A vibration compression molding machine characterized by the following.