JP2013220446A - Method of manufacturing powder molding and powder molding apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a powder molding and a powder molding apparatus that pressurize material powder by a DDV type servo driving device for pressurization by moving an upper punch forward and backward at a high speed by an upper punch driving section, and stably adjust a compression amount of the powder molding by the DDV type servo driving device for pressurization in a pressurization process.SOLUTION: There is provided a powder molding apparatus 1 that includes a die 11, a lower punch 21, an upper punch 31, an upper punch driving section 72 which moves the upper punch 31 forward and backward, and a plurality of DDV type servo driving devices 75 for pressurization coupled to the upper punch 31 by a pressurization coupling section 76, wherein the material powder P in a charging section A is pressurized by the plurality of DDV type servo driving devices 75 for pressurization after the upper punch driving section 72 moves the upper punch 31 forward. Before shifting to the pressurization process, force in the direction opposite to the pressurizing force of the DDV type servo driving devices 75 for pressurization is generated by the upper punch driving section 72.

Description

  The present invention relates to a method for producing a powder molded product and a powder molding apparatus.

  As is well known, in the fields of automobile parts, electronic parts, cutting tools, etc., powder sintering is performed by forming ceramic powders such as metal powders and alumina into powder molded products and sintering the powder molded products. The powder metallurgy sintering method for manufacturing products made of products is widely used.

  The powder metallurgy sintering method is a powder forming apparatus including a die, a lower punch that defines a filling portion together with the die, and an upper punch that is supported so as to be able to advance and retreat toward the filling portion. The material powder is filled in, and the material powder is pressed by the upper punch and the lower punch to form a powder molded product. And this powder molded product is manufactured by sintering under a predetermined condition.

  The above powder molded product shrinks significantly during sintering, and the magnitude of the shrinkage is greatly affected by the density of the powder molded product. It is desirable to suppress shrinkage during sintering.

  Therefore, in order to reduce the unevenness of the density distribution of the powder molded product, a die fixing method in which the die is fixed and the upper punch is lowered and the lower punch is raised and the material powder in the filling portion is pressed from above and below (for example, When the lower punch is fixed and the upper punch is lowered, the material powder in the filling portion is compressed even from the lower side by lowering the die at a speed about half that of the upper punch. Withdrawal method (see, for example, Patent Document 2) that is molded in practice has been put to practical use. However, if the supply amount of the material powder is biased depending on the portion of the filling portion during filling, the density distribution of the powder molded product may be biased. It was difficult to avoid.

  In addition, in order to reduce the uneven density distribution of the powder molded product and improve the accuracy of the powder sintered product, the vertical position of the upper punch is controlled by the DDV servo drive device to adjust the compression amount of the material powder The technique to do is developed (for example, refer patent document 3).

Japanese Patent Laid-Open No. 1-181997 JP-A-5-92299 JP 2010-234377 A

  However, when powder-molded products are powder-molded at high speed and high output, the upper punch driving unit for moving the upper punch at high speed and the material powder is pressed at high output after being moved at high speed and reaching the filling unit When using a powder molding machine equipped with a pressurizing DDV type servo drive device, and the upper punch drive unit and the pressurization DDV type servo drive device are both arranged on the upper platen, the powder is used regardless of the shape of the powder molded product. There is a technical request to further reduce the uneven density distribution of molded products.

  In such a case, when the DDV type servo drive device for pressurization is used exclusively for the push side (the side for pressurizing the material powder), when the upper punch moved at high speed moves to the pressurization process, In some cases, a difference in the amount of advance occurs in the rod of the DDV servo drive device, and the upper punch plate is tilted. When the upper punch plate is tilted and the process proceeds to the pressurizing process, the material is moved by the pressurizing DDV servo drive device. In some cases, the powder may not be sufficiently compressed.

  The present invention has been made in consideration of such circumstances. The upper punch drive unit advances and retracts the upper punch with respect to the die, and the compression amount of the material powder is adjusted by the pressurizing DDV type servo drive device. When pressurizing, powder compaction can be adjusted stably by the DDV servo drive device for pressurization in the pressurization process, and as a result, the density distribution of the powder compact can be reduced. An object of the present invention is to provide a product manufacturing method and a powder molding apparatus.

In order to achieve the above object, the present invention proposes the following means.
The invention described in claim 1 includes a die formed with a filling portion filled with a material powder, a lower punch attached to the die so as to be relatively movable, and defining the filling portion together with the die, An upper punch disposed above the die so as to be movable back and forth with respect to the filling portion, an upper punch driving portion connected to the upper punch via the connecting portion, and moving the upper punch forward and backward, and the upper punch driving An upper platen provided with a portion, and a plurality of pressurizing DDV type servo drive devices provided on the upper platen and connected via the pressure connecting portion disposed at a distance from the upper punch and the connecting portion; A control unit that pressurizes the material powder in the filling unit by the plurality of pressurizing DDV type servo driving devices after the upper punch driving unit advances the upper punch, The control unit Before the upper punch starts pressurizing the material powder in the filling portion, at least one of the plurality of pressurizing connecting portions is caused to generate a force opposite to the pressing force of the pressurizing DDV servo drive device. It is comprised by these.

  The invention described in claim 5 includes a die formed with a filling portion filled with material powder, a lower punch attached to the die so as to be relatively movable, and defining the filling portion together with the die, An upper punch disposed above the die so as to be movable back and forth with respect to the filling portion, an upper punch driving portion connected to the upper punch via the connecting portion, and moving the upper punch forward and backward, and the upper punch driving An upper platen provided with a portion, and a plurality of pressurizing DDV type servo drive devices provided on the upper platen and connected via the pressure connecting portion disposed at a distance from the upper punch and the connecting portion; A powder molded product by a powder molding apparatus configured to press the material powder in the filling section by the plurality of pressurizing DDV servo driving devices after the upper punch driving portion advances the upper punch. In the manufacturing method, before the upper punch starts pressurizing the material powder in the filling portion, at least one of the plurality of pressurizing connecting portions is opposite to the pressurizing force of the DDV servo drive device for pressurization. It is characterized by generating the force of

According to the powder molding method and the powder molding apparatus according to the present invention, before the upper punch pressurizes the material powder in the filling portion, the plurality of pressure connection portions for connecting the upper punch and the pressing DDV servo drive device are connected. By generating a force in the direction opposite to the applied pressure in at least one of them, a DDV servo drive device for pressurization with a large rod advance amount among DDV servo drive devices for pressurization (for example, via the upper punch plate) A backward force acts on the upper punch, so that the inclination of the filling portion becomes small (for example, horizontally), and the bias of the rod advance amount of each pressurizing DDV servo drive device becomes small.
As a result, the inclination of the upper punch with respect to the filling portion is reduced, and it becomes possible to stably adjust the compression amount of the material powder by the pressurizing DDV type servo drive device after shifting to the pressurizing process, thereby reducing the deviation of the density distribution. As a result, the accuracy of the powder-sintered product when the powder-molded product is sintered into a powder-sintered product can be improved.

  Here, to reduce the inclination of the upper punch relative to the filling portion, when pressing the material powder filled in the filling portion, the deviation of the rod advance amount of the DDV servo drive device for pressurization is reduced, This refers to adjusting the tilt of the upper punch in a direction in which the amount of compression of the material powder can be adjusted by advancing the rod of the DDV servo drive device. For example, when the axis of the upper punch corresponds to the axis of the filling part Etc.

  The invention described in claim 2 is the powder molding apparatus according to claim 1, wherein when the upper punch driving unit is a DDV type servo driving device, the control unit controls the connecting unit to A signal corresponding to a position in the forward direction with respect to the pressure connecting portion is output to the upper punch driving portion.

  According to the powder molding apparatus according to the present invention, the DDV servo drive device as the upper punch drive unit causes the connecting portion to correspond to the position in the forward direction with respect to the pressurizing connecting portion. A force opposite to the applied pressure of the servo drive device can be generated stably.

  The invention described in claim 3 is the powder molding apparatus according to claim 1, wherein when the upper punch driving unit is a ball screw driving unit, the control unit adds the connecting unit to the adding unit. A signal corresponding to the position in the forward direction of the pressure connecting portion is output to the upper punch driving portion.

  According to the powder molding apparatus of the present invention, the ball screw driving device as the upper punch driving unit causes the connecting portion to correspond to the position in the forward direction with respect to the pressurizing connecting portion. A force opposite to the applied pressure of the driving device can be generated stably.

  A fourth aspect of the present invention is the powder molding apparatus according to the first aspect, wherein the upper punch driving portion is a hydraulic cylinder, and the back pressure accompanying the advance of the upper punch is adjusted in the hydraulic cylinder. In the case where back pressure adjusting means is provided, the control unit applies to the back pressure adjusting means the at least one of the plurality of pressurizing connecting parts by the back pressure by applying the pressurizing DDV servo drive device. A signal for generating a force opposite to the pressure is output.

  According to the powder molding apparatus according to the present invention, the hydraulic cylinder as the upper punch drive unit is opposite to the pressurization force of the DDV servo drive unit for pressurization at the connecting part by adjusting the back pressure when the rod is advanced. The direction force can be generated stably.

  According to the powder molding method and the powder molding apparatus according to the present invention, before the upper punch pressurizes the material powder in the filling portion, among the plurality of pressure coupling portions coupled to the upper punch and the pressurizing DDV servo drive device. Since at least one force is generated in the opposite direction to the applied pressure, the inclination of the upper punch with respect to the filling portion is reduced, and the compression adjustment of the material powder by the pressing DDV servo drive device after shifting to the pressing process is stable. As a result, the deviation of the density distribution can be stably reduced.

It is a figure which shows the outline of the powder shaping | molding apparatus which concerns on one Embodiment of this invention. It is a figure which shows an example of arrangement | positioning of the DDV type servo drive device for a top punch movement and DDV type servo drive device for pressurization concerning one Embodiment. It is a figure which shows an example of a structure of the DDV type servo drive device for upper punch movement which concerns on one Embodiment. It is a figure which shows an example of the circuit structure of the DDV type servo drive device for upper punch movements and the DDV type servo drive device for pressurization concerning one Embodiment. It is a figure which shows an example of a structure of the DDV type servo drive device for a pressurization which concerns on one Embodiment. It is a figure which shows an example of the control part which concerns on one Embodiment. It is a figure which shows an example of schematic structure of the database which concerns on one Embodiment. It is a block diagram which shows the outline of operation | movement of the powder molding apparatus which concerns on one Embodiment. It is a block diagram which shows the outline of an effect | action of the powder molding apparatus which concerns on one Embodiment. It is a figure explaining operation | movement of the powder shaping | molding apparatus which concerns on one Embodiment, (A) is the operation | movement of the upper punch in a powder shaping | molding cycle, (B) is the upper punch of the timing shown by A in FIG. 10 (A), It is a figure which shows the detail of operation | movement of the DDV type servo drive device for upper punches, and the DDV type servo drive device for pressurization.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a diagram showing a powder molding apparatus 1 according to this embodiment, which includes a die set (die) 10 and a powder molding press 50. For example, metal powder (material powder) P is inclined and filled. Powder molding is performed by a die fixing method in which an upper punch and a lower punch are moved forward and backward on a fixed die.

The die set 10 includes a die 11 having a through-hole formed at the center, a lower punch 21 disposed below the die 11, and an upper punch 31 disposed above the die. The filling portion A is defined by inserting the lower punch 21, and the filling portion A is filled with the metal powder P.
The die 11 is disposed at the center of the die plate 12, and a guide hole 18H is formed in the die plate 12.

  The lower punch 21 is erected on the lower punch plate 13 which is movable relative to the base plate 14 fixed on the main body bed 68. The lower punch plate 13 is a DDV servo drive device 22 for lower punch. The guide rod 40 that is connected to the push-up plate 44 through the lower punch plate 13 and is inserted below the lower punch plate 13 is inserted into the guide hole of the push-up plate 44, thereby suppressing horizontal displacement with respect to the push-up plate 44. However, relative movement in the vertical direction is possible.

  Further, the push-up plate 44 is connected to the T-shaped joint 45, and the T-groove 45A of the T-shaped joint 45 is connected to the T-shaped portion of the lower ram 61. 21 and the lower punch plate 13 are movable in the vertical direction together with the push-up plate 44.

The guide rod 41 standing below the die plate 12 is inserted into the guide hole of the base plate 14 so that the die plate 12 can move relative to the base plate 14 in the vertical direction.
Further, the lower punch 21 is movable in the vertical direction relative to the push-up plate 44 by the lower punch DDV servo drive device 22 being advanced and retracted by the position control function. The relative position in the vertical direction can be adjusted.

  The upper punch 31 is fixed to the upper punch plate 34 and is erected downward (in the direction of the die 11) on the upper punch plate 34 so that the upper punch 31 can be inserted into the filling portion A.

  In the upper punch plate 34, the guide rod 18 is erected, and the guide rod 18 is slidably inserted into a guide hole 18 </ b> H formed in the die plate 12, and the upper punch 31 is vertically moved with respect to the die 11. The upper punch 31 is prevented from shifting from the die 11 when moving. Further, the upper punch plate 34 is connected to the upper punch DDV servo drive device 72 of the powder molding press 50 by the T-joint and the pressurizing DDV servo drive device 75, and is moved in the vertical direction. ing.

  The powder molding press 50 includes a press lower main body 60, a press upper main body 70, a control unit 80, a shoe box 90, and a laser shape measuring instrument (not shown). Based on the thickness of the powder molded product W, the vertical position of the upper punch 31 is adjusted to adjust the amount of compression of the metal powder P by the upper punch 31.

The lower press body 60 includes a lower ram 61, a lower ram drive 62, a main body support 63, a lower ram drive support plate 64, a lower ram base plate 65, a detent rod 66, and a lower ram guide. The plate 67 and the main body bed 68 are provided. The main body support portion 63, the lower ram drive portion support plate 64, the lower ram base plate 65, the lower ram guide plate 67, and the main body bed 68 are arranged from below. Arranged in order, the detent rod 66 is erected between the lower ram base plate 65 and the lower ram guide plate 67.
Further, the press lower main body 60 and the press upper main body 70 are connected by a connecting member 52.

  The lower ram drive unit 62 includes a lower ram drive motor 62M provided on the lower ram drive unit support plate 64, a drive pulley 62A provided on a rotating shaft of the lower ram drive motor 62M, a transmission belt 62B, and a driven pulley 62C. And a lower ram drive shaft 62D concentric with the driven pulley 62C, the transmission belt 62B is wound around the drive pulley 62A and the driven pulley 62C, and the rotation of the lower ram drive motor 62M is driven by the driven pulley 62C. The lower ram drive shaft 62D is transmitted and rotated.

  Further, a male screw 62E formed on the front end side of the lower ram drive shaft 62D is disposed so as to be screwed with a female screw 61A extending along the axis from the center of the lower end surface of the lower ram 61. By rotating 62D, the lower ram 61 is raised and lowered.

  The lower ram 61 is formed with a female screw 61A engageable with a male screw 62E on the lower side of the lower ram 61. The outer periphery of the lower ram 61 is inserted into a guide member 67A provided on the lower ram guide plate 67. The lower ram 61 has a base end (lower side) fixed to the lower ram base plate 65 and is erected on the lower ram base plate 65.

  The lower ram base plate 65 has a through hole 65A formed at the center thereof, the female screw 61A of the lower ram 61 is concentric with the through hole 65A, and the lower ram drive shaft 62D is inserted into the female screw 61A of the lower ram 61. The male screw 62E and the female screw 61A are engaged.

Further, when the non-rotating rod 66 passes through the hole 65B formed in the lower ram base plate 65, when the lower ram drive shaft 62D of the lower ram drive motor 62M rotates, the lower ram 61 and the lower ram base plate 65 are It is prevented from rotating.
As a result, when the lower ram drive shaft 62D of the lower ram drive motor 62M is rotated, the male screw 62E of the lower ram drive shaft 62D and the female screw 61A of the lower ram 61 are engaged to rotate the lower ram drive motor 62M. Is converted into vertical movement, so that the lower ram 61 moves forward and backward.

  The press upper body 70 includes an upper platen 71, an upper punch DDV servo drive (upper punch drive) 72, and a pressurization DDV servo drive 75. In this embodiment, for example, FIG. As shown in FIG. 4, a DDV servo drive device 72 for upper punch is erected at the center of the upper surface of the upper platen 71. The DDV servo drive device 75 includes, for example, two sets of DDV servo drive devices. The two sets of DDV type servo drive devices 75 are arranged orthogonal to each other with D72 and the filling portion A interposed therebetween. The two-dot chain line indicates the upper punch 31, the die 11, and the filling portion A.

  With this configuration, the vertical position of the upper punch 31 in the axial direction in which the upper punch 31 rises and descends, and the inclination of the tip surface of the upper punch 31 (the relative vertical position of the portion facing the filling portion A). It can be adjusted.

The upper punch DDV type servo drive device 72 has a concave portion formed in the circumferential direction at the tip of the rod, and this concave portion is formed on a T joint 34B formed on a convex portion 34A formed in the central portion of the upper punch plate 34. By being connected, a connecting portion 73 between the upper punch DDV servo drive device 72 and the upper punch 31 is formed.
Further, the upper punch DDV servo drive device 72 moves the upper punch plate 34 and the upper punch 31 in the vertical direction as the rod advances and retreats.

  The pressurizing DDV servo drive device 75 is connected to the upper punch plate 34 through a pressurizing connecting portion 76 so as to be able to swing, and the upper punch 31 through the upper punch plate 34 as the rod advances. The metal powder P in the filling portion A is pressurized, and the rod moves forward and backward when the upper punch DDV servo drive device 72 moves the upper punch 31 up and down.

In this embodiment, the upper punch DDV servo drive device 72 has a schematic configuration as shown in FIG. 3, for example. The lower punch DDV servo drive device 22 for advancing and retracting the lower punch 21 has the same configuration.
Hereinafter, a bi-directional propulsion type DDV (Direct Drive Volume Control) servo drive device constituting the upper punch DDV servo drive device 72 will be described with reference to FIG.

  The upper punch DDV servo drive device 72 includes an adder 72F, a servo amplifier 72G, a servo motor 72M, a hydraulic pump 72P, a hydraulic cylinder 72C, and a position detection sensor 72D. The position detection sensor 72D is hydraulic. The advance / retreat amount of the rod of the cylinder 72C is detected.

The adder 72F adds the control signal Sd related to position control or pressure control input from the outside and the feedback signal St from the position detection sensor 72D, and outputs the result to the servo amplifier 72F. The servo amplifier 72G is added from the adder 72F. The servo motor 72M is driven by amplifying this signal.
The servo motor 72M drives the hydraulic pump 72P to send pressurized hydraulic oil to the hydraulic cylinder 72C, and moves the rod of the hydraulic cylinder 72C forward or backward to adjust the advance / retreat amount.

Further, as shown in FIG. 4, the upper punch DDV servo drive device 72 includes a hydraulic cylinder 72C in which a hydraulic oil reservoir 72S and a hydraulic oil tank 72T are arranged in parallel with the hydraulic pump 72P. It is possible to adjust the difference in hydraulic oil.
A drop prevention valve 72V is provided on the side where the hydraulic oil returns when the rod of the hydraulic cylinder 72C moves forward. The rod moves forward when the drop prevention valve 72V is opened, and the drop prevention valve 72V The forward movement of the rod is stopped by the closed state.

As a result, a control signal is output to the upper punch DDV servo drive device 72, and the position of the upper punch DDV servo drive device 72 can be controlled by changing the advance / retreat amount of the rod of the hydraulic cylinder 72C. .
Further, pressure sensors 72A and 72B are connected to the rod side and the head side of the hydraulic cylinder 72C so that the pressure of each hydraulic oil can be detected.
It goes without saying that other well-known types of DDV servo drive devices other than those described above are applicable.

  Further, the DDV servo drive device 75 for pressurization has a schematic configuration as shown in FIG. 5, and when the upper punch 31 pressurizes the metal powder P in the filling portion A in the pressurizing step, the upper punch The bias of the advance amount at each position 31 is adjusted.

  The pressurizing DDV servo drive device 75 includes an adder 75F, a servo amplifier 75G, a servo motor 75M, a push-side dedicated hydraulic pump 75P, a hydraulic cylinder 75C, and a position detection sensor 75D, and the position detection sensor 75D. Detects the advance amount of the rod of the hydraulic cylinder 75C.

  The adder 75F, the servo amplifier 75G, and the position detection sensor 75D are the same as those in the DDV type servo drive device 72 for the upper punch, and the servo motor 75M drives the hydraulic pump 75P to pressurize the hydraulic oil that has been pressurized. The rod is advanced to 75C and the rod advance amount of the hydraulic cylinder 75C is adjusted.

  Further, as shown in FIG. 4, the pressurizing DDV servo drive device 75 includes a hydraulic cylinder 75C in which a hydraulic oil reservoir 75S, a hydraulic oil tank 75T, and a prefill valve 75V are arranged in parallel with the hydraulic pump 75P. It is possible to adjust the difference in hydraulic oil in the hydraulic cylinder 75C.

The prefill valve 75V can be controlled to be opened and closed by the pilot pressure of the hydraulic oil supplied from the pilot pump 78. When the rod of the hydraulic cylinder 75C advances, the prefill valve 75V is opened by the pilot pressure, and the hydraulic oil is supplied to the hydraulic cylinder 75C. By enabling a large amount of oil to be sucked from the tank T, the rod of the pressurizing DDV type servo drive device 75 is advanced at a high speed and the backflow of the hydraulic oil from the hydraulic cylinder 75C to the hydraulic oil tank T is prevented. The rod of the DDV servo drive device 75 for pressure corresponds to the pressurizing process, and when the rod of the DDV servo drive device 75 for pressurization moves back, it acts as a check valve so that high-speed advance, pressurization process, and reverse are controlled appropriately. It is possible.
A pressure sensor 75A is connected to the rod side of the hydraulic cylinder 75C so that the pressure of the hydraulic oil can be detected.

As a result, the control signal is output to the pressurizing DDV servo drive device 75 to adjust the advancement amount of the rod of the hydraulic cylinder 75C to control the pressure and the position of the pressurization DDV servo drive device 75. It has become.
It goes without saying that other well-known types of DDV servo drive devices other than those described above are applicable.

  The shoe box 90 moves forward and backward on the die plate 12 toward the filling portion A in response to a signal output from the control unit 80 to the drive source of the shoe box 90. The upper punch 31 and the lower punch 21 is sequence-controlled.

  The laser shape measuring instrument (not shown) measures the thickness of the powder molded product W placed outside the die 11 and carried out. For example, the laser beam irradiated while moving the powder molded product W In response to the reflected light, the thickness of the powder molded product W is scanned from the measurement start end to the measurement end end to detect shape data, and the thickness data from the measurement start end to the measurement end end is controlled. The data is transmitted to the unit 80.

  For example, as illustrated in FIG. 6, the control unit 80 includes an input unit 81, a memory 82, a calculation unit 83, a hard disk device 84, an output unit 86, and a communication line for communicating these mutual data and the like. The input unit 81 includes a DDV servo drive device 72 for upper punch, a DDV servo drive device 75 for pressurization, a lower ram drive motor 62M, an upper ram drive motor 73M, and a DDV servo drive device for lower punch. 22, a laser shape measuring instrument is connected, and an output punch 86 has an upper punch DDV servo drive 72, a pressurization DDV servo drive 75, a lower ram drive motor 62M, an upper ram drive motor 73M, and a lower punch. A DDV servo drive device 22 is connected.

  The input unit 81 includes, for example, a data input device such as a keyboard (not shown), and outputs settings and the like to the arithmetic unit 83. The input unit 81 also includes the upper punch DDV servo drive device 72 and the pressurization DDV servo drive device 75. Pressure sensor and detection signal of pressure sensor of lower punch DDV servo drive device 22, rotation angle detection signal of encoder (not shown) of lower ram drive motor 62M and upper ram drive motor 73M, measurement from laser shape measuring instrument Signals are input, and these signals are output to the calculation unit 83.

  The calculation unit 83 reads, for example, a program stored in the ROM of the memory 82 and executes the program, and the operation program data of the powder molding press 50 stored in the memory 82, the upper ram DDV type servo drive device 72, and the lower Based on the signal from the encoder of the ram drive motor 62M, a signal for controlling the position, speed, stop operation, etc. of the upper punch 31 and the lower ram 61 is output to the DDV servo drive device 72 and the lower ram drive motor 62M. It has become.

Further, the rod advance amount of each pressurization DDV servo drive device 75 is calculated by referring to the database 85 with the measurement data from the laser shape measuring instrument, and is output to each pressurization DDV servo drive device 75. ing. In this embodiment, a four-axis control system (multiple-axis control system (multiple-axis) is provided, in which the rod advance amounts of the plurality of pressurizing DDV-type servo drive devices 75 can be independently controlled based on measurement data from the laser shape measuring instrument. Axis control system) is preferred.
Further, when the rod advance amount of each pressurization DDV servo drive device 75 is controlled without relying on measurement data, such as when the pressurization characteristics in powder molding are known, any pressurization DDV servo drive A master-slave system in which the device 75 is a master and the other DDV servo drive device 75 for pressurization is controlled based on the position of the master may be applied.
In addition, a signal related to tilt filling of the lower punch DDV servo drive device 22 and generation of vibration at the time of filling may be output to the DDV servo drive device 22 for lower punch.

  The output unit 86 outputs the signal from the calculation unit 83 to the upper punch DDV servo drive device 72, the pressurization DDV servo drive device 75, the lower punch DDV servo drive device 22, and the lower ram drive motor 62M. It is like that.

For example, a database 85 as shown in FIG. 7 is stored in the hard disk device 84.
In the database 85, the numerical data of the rod advance amount of the DDV servo drive device 75 for pressurization for setting the target thickness according to the thickness (measurement data) of the target portion of the powder molded product W is obtained for each applied pressure. It is configured in the form of a data table. Parameters ΔL1 to ΔL4 in FIG. 7 represent the rod advance amount of the pressing DDV servo drive device 75 corresponding to the compression amount of the metal powder P.

Next, with reference to FIGS. 8-10, the operation | movement until it transfers to a pressurization process in the powder shaping | molding apparatus 1 after filling with the metal powder P is demonstrated.
8 and 9 are diagrams for explaining the outline of the operation and action of the powder molding apparatus 1 according to an embodiment.
FIG. 10 is a diagram showing the operation of the upper punch 31 (upper punch DDV servo drive device 72 and pressurization DDV servo drive device 75) of the powder molding apparatus 1. FIG. FIG. 10B shows the operation of the upper punch 31 in the powder molding cycle. FIG. 10B shows the upper punch 31, the upper punch DDV servo drive device 72, and the pressurizing DDV servo in the portion surrounded by a circle K in FIG. FIG. 7 is a diagram showing details of the operation of the driving device 75.

(1) First, the control unit 80 drives the shoe box 90 to fill the filling portion A with the metal powder P while the upper punch 31 is stopped at the top dead center (S1).

(2) Next, the control unit 80 outputs a signal for lowering the upper punch 31 to advance the respective rods of the upper punch DDV servo drive device 72 and the pressurization DDV servo drive device 75, and to move the upper punch plate. 34 is lowered (S2).
At this time, the control unit 80 outputs to the pilot pump 78P, opens the prefill valve 75V, causes a large amount of hydraulic oil to flow into the pressurizing DDV servo drive device 75, and pressurizes the DDV servo drive device 75. Is adapted to advance at high speed (low pressure).
As a result, the rods of the upper punch DDV servo drive device 72 and the pressurizing DDV servo drive device 75 move forward at high speed, and the upper punch 31 descends at high speed as shown in FIG.

(3) Next, before proceeding to the pressurizing step in which the upper punch 31 pressurizes the metal powder P in the filling portion A by the pressurizing DDV servo drive device 75, the control unit 80 performs the upper punch DDV servo. A signal is output to the driving device 72 such that the vertical position of the connecting portion 73 is a rearward position in the forward direction relative to the vertical position of the pressure connecting portion 76 (S3).
As a result, as shown in FIG. 10B, the connecting portion 73 connected to the rod of the upper punch DDV servo drive device 72 is connected to the rod of the pressurization DDV servo drive device 75. For example, the portion 76 is positioned above the portion 76 by h. Here, FIG. 10B shows details of the timing surrounded by a circle K in FIG. 10A.
Note that the position in the vertical direction of the connecting portion 73 that is behind the position in the vertical direction of the pressure connecting portion 76 means that the pressure applied to the DDV servo drive device 75 for pressurization is applied to at least one of the plurality of pressure connecting portions 76. It means a position where the connecting portion 73 and the pressure connecting portion 76 correspond so that a force in the opposite direction is generated.
The operation in S3 is as shown in FIG. 9, for example.
(3-1)
An upward force is applied to the pressure connecting portion 76 by the output to the DDV servo drive device 72 for upper punch in S3 (S31).
(3-2)
In S31, when an upward force is applied to the pressure connecting portion 76, the inclination of the upper punch plate 34 becomes horizontal, for example, and is adjusted to n so that the axis of the upper punch 31 and the axis of the filling portion A substantially coincide with each other. (S32).
(3-3)
When the inclination of the upper punch plate 34 is adjusted so that the axis of the upper punch 31 and the axis of the filling portion A substantially coincide with each other, the rod of the pressurizing DDV servo drive device 75 is applied to the metal powder P in the filling portion A. It is possible to move forward stably (S33).
As a result, when the process proceeds to the pressurizing step, the compression amount of the metal powder P can be adjusted sufficiently stably by the rod advance of the pressurizing DDV servo drive device 75.

(4) When the process proceeds to the pressurizing step, the amount of advancement of the rod of the pressurizing DDV servo drive device 75 is adjusted to reduce the bias of the compression amount of the metal powder P (S4).

(5) After that, the control unit 80 outputs to the pilot pump 78P, closes the prefill valve 75V, causes high pressure hydraulic fluid to flow from the pump 75P into the pressurizing DDV servo drive device 75, and pressurizes DDV. The rod of the mold servo drive device 75 is advanced at a high pressure while adjusting the amount of compression, and as shown in FIG. 10, the metal powder P is pressurized in the pressurizing step, and when the upper punch 31 reaches the bottom dead center, the upper punch 31 At the bottom dead center.

  Thereafter, the control unit 80 stops driving the pumps 72P and 75P, stops the pressurization by the upper punch DDV servo drive device 72 and the pressurization DDV servo drive device 75, and then releases the pressure. Then, the pump 72P is caused to discharge the hydraulic oil in the direction in which the rod of the upper punch DDV servo drive device 72 is raised, and the upper punch plate 34 and the upper punch 31 are raised. At this time, in the pressurizing DDV type servo drive device 75, the hydraulic oil flows from the hydraulic oil reservoir 75S to the side where the rod is raised.

According to the powder forming apparatus 1, before the upper punch 31 starts to press the metal powder P in the filling portion A, a plurality of pressurizing DDV servo drive devices 75 connected to the upper punch plate 34 are connected. Since an upward force is generated in at least one of the pressure coupling portions 76, an upward force acts on the pressure DDV servo drive device 75, and the rod advance amount of each pressure DDV servo drive device 75 The bias is reduced. As a result, the inclination of the upper punch 31 with respect to the filling portion A is reduced, and the compression amount of the metal powder P by the pressurizing DDV type servo drive device 75 after shifting to the pressurizing process is stably adjusted, so that the deviation of the density distribution is Can be small.
As a result, the accuracy of the powder sintered product can be improved.

  Further, since the rod advance / retreat amount of the pressurizing DDV servo drive device 75 is adjusted so as to reduce the bias of the compression amount of the metal powder P, the bias of the density distribution of the powder molded product W can be reduced. it can. As a result, it is possible to efficiently form a powder molded product having a small uneven density distribution.

  Further, according to the powder molding apparatus 1, the thickness deviation of the molded powder molded product W is accurately measured in a short time without directly contacting the powder molded product with a laser shape measuring instrument, and the pressurizing DDV type Since feedback is provided to the position control of the servo drive device 75, the thickness deviation of the next powder molded product W can be adjusted easily and efficiently.

Note that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the invention.
For example, in the above embodiment, the case where the upper punch drive unit is the upper punch DDV servo drive unit 72 has been described. However, a ball screw drive unit may be used as the upper punch drive unit. Similarly to the punching DDV servo drive device 72, it is also possible to output a signal for causing the connecting portion 72 to correspond to the position in the rearward direction of the pressure connecting portion 76 to the ball screw driving device.

  Further, when the upper punch driving unit is a hydraulic cylinder as the upper punch driving unit, and the back pressure adjusting unit for adjusting the back pressure accompanying the advancement of the upper punch 31 is provided in the hydraulic cylinder, the back pressure adjusting unit In addition, a signal that generates a force in the opposite direction to the pressing force of the pressurizing DDV servo drive device 75 may be output to at least one of the plurality of pressurizing connecting portions 76 by back pressure. In this case, as the back pressure adjusting means, a pressure adjusting valve, a flow rate adjusting valve, or the like provided in a hydraulic line that generates back pressure when the rod of the hydraulic cylinder lowers the upper punch 31 can be used.

  Further, in the above embodiment, the powder molding apparatus 1 serves as the upper punch drive unit as the upper punch DDV servo drive device 72, the ball screw drive hydraulic cylinder, and the back pressure for adjusting the back pressure accompanying the advance of the upper punch. Although the case of the hydraulic cylinder provided with the pressure adjusting means has been described, the upper punch driving unit may be configured by other means.

  In the above-described embodiment, the case where the four pressing DDV servo drive devices 75 are provided has been described. However, for example, a plurality of pressing DDV servo driving devices 75 other than the four pressing DDV servo driving devices 75 may be provided. .

  Moreover, in the said embodiment, although the case where the powder shaping | molding apparatus 1 was equipped with the laser shape measuring device as a shape measuring means of the powder molded product W was demonstrated, it replaced with a laser shape measuring device and used an ultrasonic wave and a radiation, for example. The shape measuring instrument may be used, or the shape measuring means may not be provided.

  Further, in the above-described embodiment, the case where the rod advance amount of the pressurizing DDV servo drive device 75 is adjusted when there is a portion outside the allowable range with respect to the thickness of the powder molded product W has been described. For example, the rod advance amount may be adjusted based on a signal from the laser shape measuring instrument each time the powder is compacted without setting the range.

  Further, in the above-described embodiment, the case where the control unit 80 refers to the database 85 when calculating the rod advance amount of each pressurization DDV type servo drive device 75 has been described. It may be calculated based on the calculated mathematical formula.

  In the above embodiment, the position control of the lower punch has been described by the CNC control method having the screw structure provided on the lower ram drive shaft 62D and the lower ram 61. However, the control method and screw other than the CNC control method are described. The lower punch 21 may be operated using a driving device other than the structure. Further, instead of the encoder, other position measuring means such as a linear scale may be used.

In the above-described embodiment, the case where the lower punch 21 can be operated by the lower punch DDV servo drive device 22 has been described. However, for example, the lower punch DDV servo drive device 22 may not be used. The die 11 may be lowered relative to the lower punch 21.
In addition, when filling the metal powder P, the lower punch DDV servo drive device 22 may be used for tilt filling or the metal powder P may be vibrated.

  In the above embodiment, when the molding in the powder molding apparatus 1 is a die fixed molding method in which the die 11 is fixed to the powder molding press 50 and the upper punch 31 and the lower punch 21 are advanced relative to the die 11. However, it can also be applied to the withdrawal molding method.

  In the above-described embodiment, the case where each of the lower punch 21 and the upper punch 31 is single has been described. However, one or both of the lower punch 21 and the upper punch 31 start from a punch that advances and retracts in a plurality of stages in the compaction direction. It is also possible to adopt a configuration in which either or both of the lower punch 21 and the upper punch 31 are provided with a core rod.

  Moreover, in the said embodiment, although the case where the powder molded product W was shape | molded using the metal powder P as material powder was described, it replaced with the metal powder P, and cemented carbide alloy powder, ceramic powder, cermet powder, etc. It is also possible to use cutting inserts, cutting tools, and other various products for production.

  In the above embodiment, the case where the storage medium for storing the program is a ROM has been described. However, for example, a storage medium such as an EP-ROM, a hard disk, a flexible disk, a magneto-optical disk, or a nonvolatile memory Storage means other than ROM, such as a card, may be used. Further, it goes without saying that a known method in which the operation of the above-described embodiment is realized by the processing in the control unit 80 can be applied.

  According to the powder molding apparatus and the method of manufacturing a powder molded article according to the present invention, a powder molded article with a small deviation in density distribution can be efficiently obtained by stably adjusting the rod advance amount of the DDV servo drive device for pressurization. Therefore, it can be used industrially.

A Filling part P Metal powder (material powder)
DESCRIPTION OF SYMBOLS 1 Powder shaping | molding apparatus 11 Die 21 Lower punch 31 Upper punch 71 Upper platen 73 Connection part 76 Pressure connection part 72 DDV type servo drive device for upper punch (upper punch drive part)
75 DDV servo drive for pressurization

Claims (5)

A die formed with a filling portion filled with material powder;
A lower punch mounted relative to the die and defining a filling portion with the die;
An upper punch disposed above the die so as to be movable back and forth with respect to the filling portion,
An upper punch driving unit that is connected to the upper punch via a connecting part, and advances and retracts the upper punch,
An upper platen provided with the upper punch driving unit;
A plurality of pressurizing DDV servo drive devices provided on the upper platen and connected via pressure connecting portions arranged at intervals from the upper punch and the connecting portion;
A control unit that pressurizes the material powder in the filling unit by the plurality of pressurizing DDV servo driving devices after the upper punch driving unit advances the upper punch,
The controller is
Before the upper punch starts pressurizing the material powder in the filling portion, at least one of the plurality of pressurizing connecting portions is caused to generate a force opposite to the pressing force of the pressurizing DDV servo drive device. It is comprised in the powder shaping | molding apparatus characterized by the above-mentioned. The powder molding apparatus according to claim 1,
When the upper punch drive unit is a DDV servo drive device for upper punch,
The controller is
A powder molding apparatus, characterized in that a signal for causing the connecting portion to correspond to a position in the rearward direction relative to the pressure connecting portion is output to the upper punch driving portion. The powder molding apparatus according to claim 1,
When the upper punch driving unit is a ball screw driving device,
The controller is
A powder molding apparatus, characterized in that a signal for causing the connecting portion to correspond to a position in the rearward direction relative to the pressure connecting portion is output to the upper punch driving portion. The powder molding apparatus according to claim 1,
When the upper punch drive unit is a hydraulic cylinder and the hydraulic cylinder is provided with back pressure adjusting means for adjusting the back pressure accompanying the advance of the upper punch,
The controller is
The back pressure adjusting means outputs a signal that causes the back pressure to generate a force in a direction opposite to the pressurizing force of the pressurizing DDV servo drive device in at least one of the plurality of pressurizing connecting portions. Powder molding equipment. A die formed with a filling portion filled with material powder;
A lower punch mounted relative to the die and defining a filling portion with the die;
An upper punch disposed above the die so as to be movable back and forth with respect to the filling portion,
An upper punch driving unit that is connected to the upper punch via a connecting part, and advances and retracts the upper punch,
An upper platen provided with the upper punch driving unit;
A plurality of pressurizing DDV-type servo driving devices provided on the upper platen and connected to the upper punch and the connecting portion through a pressurizing connecting portion spaced apart from each other, the upper punch driving A method of manufacturing a powder molded product by a powder molding apparatus configured to press the material powder in the filling section by the plurality of pressurizing DDV type servo drive devices after the portion advances the upper punch,
Before the upper punch starts to press the material powder in the filling portion, at least one of the plurality of pressure connecting portions is caused to generate a force opposite to the pressing force of the pressing DDV servo drive device. A method for producing a powder molded product characterized by

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