JP2000233423A - Mold for powder molding and method for powder molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare a molded body with a uniform density, to make a hole on the side wall of the molded body if necessary and to make a mold into a unit and to set it outside of a molding apparatus. SOLUTION: The mold 38 is at least provided with a die plate 12 supporting a cylindrical die 10, the first plate group 16 respectively supporting one or a plurality of punches 14 being operated in the axial direction of the die 10 and being inserted into one end of the die 10 and the second plate groups 24, 26 and 28 respectively supporting one or a plurality of punches 18 and 20 and/or a core 22 being operated in the axial direction of the die 10 and being inserted into another end of the die 10. In addition, blocks 30, 32, 34 and 36 for restricting each of intervals are appropriately provided between the die plate 12 and the first plate group 16 and between the die plate 12 and the second plate groups 24, 26 and 28.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powder molding die and a powder molding method, and more particularly to a powder molding die capable of forming a molded article having a uniform density and being unitized.

[0002]

Conventionally, a powder molding method has been performed in which a powder resin or powder metal is filled into a cavity of a mold and then pressed to form a compact. In this powder molding method, since the powder filled in the mold is pressed by the upper punch, the powder on the side contacting the upper punch moves and is compacted, but the powder on the bottom side of the die almost moves. do not do. For this reason, the powder on the side in contact with the upper punch has a high density, but the powder on the bottom side of the opposite die has a low density, and after firing, the molded body may warp or warp in some cases. In addition, there is a problem that cracks and nests enter the molded product.

On the other hand, when filling a cavity of a mold with a powder made of a resin or the like, voids are often formed in the filled powder. In such a case, the molded product may have a nest or may be insufficiently filled to have poor dimensions and poor outer shape. Also, for example, if the diameter of the cavity is 2-3
When the diameter is very small, such as about mm, there is a problem that the filling of the powder is very difficult, and the defective rate increases.

When it is necessary to provide a hole in the side surface of the molded product, a pin is passed through a hole passing through the side wall of the die.
After projecting the tip of the pin into the cavity, the cavity is filled with powder. Then, the upper punch is extruded by a press to press the powder. At this time, as described above, since the powder in contact with the upper punch is moved to the bottom of the die, the powder is moved. As a result, the tip of the pin protruded into the cavity is pushed or bent or broken. For this reason, when it is necessary to provide a side hole or the like in the side wall portion of the preform formed by the powder molding method, it is provided by machining after the molding. However, this method not only increases man-hours, increases manufacturing costs, but also performs processing in a process different from molding, so that variations occur for each product, and defective products are generated. There was a problem.

[0005] Furthermore, today, there is a demand for the production of small lots of a wide variety of products, and among them, in order to improve the productivity, there is a demand for faster setup change, that is, faster mold replacement. On the other hand, the precision of the product has increased, and the adjustment work after attaching the mold to the molding apparatus has become complicated, which has taken a very long time. For this reason, the time required for setup change may be longer than the product manufacturing time, resulting in a decrease in the operation rate of the apparatus and an increase in manufacturing cost. In addition, in recent years, not only the shape and structure of the mold have been miniaturized, but also the required accuracy has been increased, for example, the clearance has been reduced. For this reason, setting the mold in the molding apparatus requires not only skill but also working in a limited space on the mold mounting base of the molding apparatus is in an extreme state. Did not.

Therefore, the present inventor can manufacture a molded article having a uniform density, can form a hole in the side wall of the molded article at the same time as molding the molded article, and can exchange the mold unit. As a result of intensive studies to obtain a powder molding die and a powder molding method that enable the present invention, the present invention has been achieved.

[0007]

The gist of the powder molding die according to the present invention is that a die plate for supporting a cylindrical die and an axially driven die are inserted into one end of the die. A first plate group for individually supporting one or a plurality of punches to be driven, and one or a plurality of punches and / or cores respectively operated in the axial direction of the die and inserted into the other end of the die; And at least a second plate group supported between the die plate and the first plate group, and between the die plate and the second plate group.

Further, in such a powder molding die, an urging force for urging the space between the die plate and the first plate group and between the die plate and the second plate group in such a direction that the respective spaces are separated and approached. To provide means.

Further, in such a powder molding die, a hole is provided through the side wall of the cylindrical die, and a core inserted through the hole and a cylinder for inserting and removing the core from a cavity formed by the die. To prepare for the plate.

Still further, in such a powder molding die,
A mounting plate fixed to a mold mounting base of the powder molding apparatus, one or more guide posts erected on the mounting plate to guide a die plate, etc .; A supporting plate provided with holes through which a press section of the apparatus can pass, and is thus unitized.

[0011] Another object of the present invention is to provide such a powder molding die, which is provided with a vibration generating means for applying a fine vibration to the die or the powder filled in the die.

Next, the gist of the powder molding method according to the present invention is that a first punch and a second punch inserted from both ends of a cylindrical die are relatively approached to each other to form a cavity formed by the die. The object is to press and mold the powder filled therein substantially equally from both sides, and to fill the dice with the powder while at least applying micro-vibration to the dice and / or the powder.

Still another aspect of the powder molding method according to the present invention is to press and mold the die and / or the powder filled in the cavity formed by the die while applying micro-vibration. It is in.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a powder molding die and a powder molding method according to the present invention will be described in detail with reference to the drawings.

As shown in FIG. 1, a die plate 12 for supporting a cylindrical die 10 and an upper punch 14 which is operated in the axial direction of the die 10 and is inserted into the upper end of the die 10 are supported. First plate 16 and die 1
A plurality of lower punches 18 and 20 that are operated in the axial direction of 0 and are inserted into the lower end of the die 10 and a group of second plates 24, 26 and 28 that individually support the lower core 22, respectively. Between the die plate 12 and the first plate 16, and between the die plate 12 and the second plate 24, the second plates 24 and 26, the second plate 2
A powder molding die 38 is provided between 6 and 28 with blocks 30, 32, 34 and 36 for regulating the respective intervals. Here, the lower punches 18 and 20 and the lower core 2
2 is formed concentrically, a cylindrical lower punch 20 is inserted into the inner diameter portion of the cylindrical lower punch 18, and the lower punch 20 is further inserted.
A lower core 22 of a solid rod shape is inserted into the inner diameter of the lower part. The shape of the molded article, that is, the shape of the cavity 40 is determined by the relative positional relationship between the lower punches 18 and 20 and the lower core 22. On the other hand, an opening 42 is inserted into the end of the upper punch 14 so as to be inserted into the cylindrical die 10, and the end of the lower core 22 is inserted into the center thereof.
Are formed.

Then, between the die plate 12 and the first plate 16, between the die plate 12 and the second plate 24, between the second plate 24 and the second plate 26, and between the second plate 26 and the second plate 28. And a control cylinder 4 for urging in a direction for separating the respective spaces.
4, 46, 48, and 50, and are configured to adjust the interval between them and the speed at which the interval is reduced. further,
The powder molding die 38 is provided with a hole 54 penetrating the side wall 52 of the die 10, a core 56 inserted into the hole 54, and a cylinder 58 for inserting and removing the core 56 from a cavity 40 formed by the die 10. Is provided on the die plate 12.

Further, the powder molding die 38 includes a second plate 28 also serving as a mounting plate fixed to a die mounting base of a powder molding device not shown, and a second plate 28 of the second plate 28.
(Mounting) The die plate 12 is erected on the plate 28
And a support plate 6 provided with a plurality of guide posts 60 for guiding components and the like, and a hole 64 attached to the other end of the guide posts 60 and through which a press portion 62 of the powder molding apparatus can pass.
6, and is configured as a unit. Here, the die plate 12 is usually fixed so as not to slide with respect to the guide post 60, whereas the first plate
The plate 16 and the second plates 24 and 26 are adapted to slide along the guide posts 60.

Therefore, the support plate 66 and the die plate 12 are fixed by the guide posts 62 so as not to change their positions, and the second (mounting) plate 28 is fixed to the mold mounting base of the powder molding apparatus. Neither position changes. Similarly, the position of the lower core 22 fixed to the second plate 28 does not change. On the other hand, the first plate 16 is raised and lowered with respect to the die plate 12 by the control cylinder 44, and the second plate 24 is
6, the second plate 26 is moved up and down with respect to the second plate 24 by the control cylinder 48. At this time, the control cylinder 50 is not necessarily required, but when the second plate 26 is operated by the control cylinder 50, the control cylinder 48 is not necessarily required.

The powder molding die 38 according to the above-described configuration includes all necessary mechanisms such as a mechanism for adjusting the dimension of the molded article and a mechanism for removing the molded article from the mold. If it is introduced from, a molded product can be formed immediately. Therefore, the powder molding die 38
Is assembled outside the powder molding apparatus, and after centering and dimensional adjustment of the punch and the die are performed in advance, the second plate 28 of the mold 38 is fixed to the mold mounting base of the powder molding apparatus.

Next, as shown in FIG. 1, the first plate 16 is pushed up by the control cylinder 44, and the lower punch 18 and the lower punch 20 are each filled with a predetermined position of the die 10 such as a powder resin. In consideration of the compression amount, it is set at a position lowered by a predetermined amount.
On the other hand, the horizontal core 56 is protruded by the cylinder 58 from the side wall 52 of the die 10 by a predetermined amount. Then, the powder resin 68 is filled in the cavities formed by the dies 10, the lower punches 18, 20, and the like.

Next, as shown in FIG. 2, the pressing section 62 of the powder molding apparatus is operated to press the first plate 16 to gradually insert the upper punch 14 into the die 10, and to apply the pressing force of the control cylinder 46. At the same time, the control cylinder 50 is operated to push up the second plate upward through the second plate 26 and the block 34, and push up the lower punches 18, 20 from below the die 10. Then, the first plate 16 is
When the contact is made, the press section 62 stops, and the positional relationship between the die 10 and the upper punch 14 is determined. When one of the second plates 24 and 26 is pushed up and the block 32 comes into contact with the die plate 12, the control cylinder 5
0 is stopped, and the positional relationship between the die 10 and the lower punches 18 and 20 is determined. In this pressurizing / compressing operation, the control cylinders 44, 46 and 48 are appropriately adjusted so that the upper punch 14 and the lower punches 18 and 20 approach the die 19 at a substantially uniform speed, and the charged powder resin 68 Is set so as to apply pressure almost equally from both sides. In particular, when the pressing surface of the upper punch 14 comes into contact with the powder resin 68 in the die 10, it is preferable that the lower punches 18 and 20 also start pressing. Therefore, the powder resin 68 does not flow in one direction along the axial direction of the die 10, and does not bend or cut the horizontal core 56 projecting from the side wall 52 of the die 10. The powder resin 68 is heated only by the pressing force or thereafter, if necessary, so that the powder resin 68 is integrated and the molded body 70 is formed. Since the pressing force acts almost evenly on the entire molded body 70, there is no so-called nest.

Next, as shown in FIG. 3, the press portion 62 of the powder molding apparatus is pulled up, the control cylinder 44 is operated, and the first plate 16 is separated from the die 10. Next, the tip of the horizontal core 56 is pulled out by the formed body 70 by the operation of the cylinder 58. Thereafter, as shown in FIG. 4, of the blocks 30, 32, 34, 36 for dimension setting, the block 34 is used.
Is replaced with another one, the second cylinder 26 is pushed up by operating the control cylinder 50, and the molded body 70 is extruded from the die 10 by the lower punch 20 to be taken out.

In the powder molding die 38 according to the above configuration, all the mold parts are assembled and configured on the second plate 28 which is a mounting plate to the base of the apparatus. The unit can be exchanged by assembling the powder molding die 38 without being restricted by space. Therefore, in setup change such as product change,
The mold set at the end of the previous production can be used as it is, or the mold can be set during the production of other types, minimizing equipment downtime,
Moreover, the mold mounting operation does not require skill. Also,
Since the powder resin 68 in the mold 10 can be pressed almost evenly from both sides, the horizontal core 56 and the like are not bent when a horizontal hole is opened using the horizontal core 56 or the like at the time of manufacturing. Since there is no need to replace or repair the mold due to the breakage of the horizontal core 56, the productivity is improved. Moreover, since the powder resin 68 in the mold 10 is pressed almost evenly from both sides, the density of each part of the molded body 70 can be substantially constant.

As described above, the powder molding die according to the present invention and the manufacturing method thereof have been described in detail, but the present invention is not limited to the above-described embodiment.

For example, in the above-described embodiment, the die plate 12 is fixed to the guide post 60.
When it comes into contact with the surface of the powder resin 68 in the inside, it is preferable that the fixing to the guide post 60 is released so that the die plate 12 can freely move in the axial direction. Since the die plate 12, that is, the die 10 can freely move in the axial direction in this way, the pressing force of the upper punch acts as a reaction force from the lower punch, so that the powder filled in the die 10 The resin 68 is pressed almost equally from both sides. In this case, a positive pressing force from the lower punch by a control cylinder or the like is not required. However, it is desirable that the center position of the die is not changed by a control cylinder or the like.

In the above-described embodiment, the lower punches 18 and 20 and the lower core 22 are provided. However, when the through-hole is not formed in the molded product, the lower core 22 is not required. Further, when there is no step in the molded product, one lower punch can be constituted. Further, when there is a step before and after the molded product, not only the lower punch but also a plurality of upper punches can be constituted. In this case, a structure similar to that of the above-mentioned second plate group can be formed by a plurality of upper punches and a first plate group that individually supports them.

Further, the configuration of the horizontal core 56 and the cylinder 58 for driving the horizontal core 56 can be provided not only at one location but also at a plurality of locations.
It is possible to arbitrarily set the depth, angle, and the like.

As shown in FIG. 5, the length of the block 72 disposed between the second plates 24 and 26 is set shorter than the distance between the second plates 24 and 26 in the initial state in which the powder resin 68 is filled. The lower punch 20 can be moved relative to the lower punch 18 in the pressing / compressing step. Therefore, the powder resin 68 at a location where the compressive force between the lower punches 18 and 20 is not sufficiently distributed,
The compression can be sufficiently performed by the pressing force from the lower punch 20.

Although only one control cylinder is shown on the same plane in the drawing, it is preferable to provide at least two control cylinders in order to translate the plate in parallel. Also, it is preferable to provide at least two or more blocks for restricting the movement of the plate. These control cylinders and blocks do not need to be arranged between the plates, but may be arranged appropriately as needed.

For example, as shown in FIG. 6, it is preferable that the control cylinders 74 and 76 are mounted on the basis of the second plate 28 as a mounting plate.
In this case, the control cylinder 74 is attached between the second plate 28 and the second plate 26 as described above, but the second plate 28 and the second plate 2
4, a control cylinder 76 is provided through a hole 78 provided in the second plate 26. With this configuration, the control of the control cylinders 74 and 76 is not affected by the other control cylinders, so that it is easy.

As the control cylinder, a multi-stage cylinder can be used to obtain a required stroke. Further, instead of the control cylinder, a part or the whole thereof may be constituted by a compression coil spring or the like, and other various urging means capable of urging each plate to the die plate may be employed. it can.

Next, in order to fill the cavity of the powder molding die according to the present invention with the powdered resin, the powder such as the resin is supplied from the opening at the top of the cavity regardless of whether it is automatic or manual. Put in it. At this time, depending on the shape of the cavity, the powder does not easily enter deeply, and a void is easily formed on the lower (bottom) side. Therefore, it is preferable to provide a vibration generating means for applying a fine vibration to the die or the powder filled in the die. When the vibration generating means irradiates ultrasonic waves or the like to directly vibrate the dice or the powder, the vibration generating means is provided at an arbitrary position. Further, in the case where the vibration generating means is for rotating the eccentric shaft or reciprocating the iron core using an electromagnetic solenoid to vibrate the dice or the die plate,
Vibration generating means is provided on a die plate supporting the dice. As described above, by supplying the powder to the die while applying the micro-vibration to the die and / or the powder, the powder is sequentially filled from the bottom side of the cavity, and the filling speed is also improved.

The application of the vibration by the vibration generating means may be performed only at the time of supplying the powder, but it is configured such that the powder filled in the die and / or the cavity is pressed and molded while applying the fine vibration. It is also possible. When vibrating at the time of molding, it is preferable to start the vibration after the upper punch is fitted into the cavity of the die. By applying pressure while vibrating, the powder spreads to every corner such as a corner in the cavity with a low pressing force, and a molded product without chipping can be obtained.

Further, a resin powder is supplied to the cavity,
Alternatively, when the resin powder is vibrated and supplied to the cavity, the powder may contact and friction with each other to generate static electricity, so that the powder may not be supplied densely into the cavity. In such a case, it is preferable to supply the resin powder while spraying ions having a polarity opposite to the polarity of the static electricity generated on the resin powder. When the polarity generated in the resin powder is unknown, a gas in which positive and negative ions are mixed may be blown.

The present invention is applicable not only to powder resin but also to powder metal (powder metallurgy). In addition, the present invention relates to a first punch (group) inserted from both ends of a cylindrical die. ) And the second punch (group) are relatively close to each other, and a powder molding die that can press the powder filled in the cavity formed by the die from both sides almost uniformly to be molded may be used. , Within the scope not departing from the gist, various improvements, modifications,
The present invention can be implemented in a modified mode.

[0036]

According to the powder molding die and the powder molding method of the present invention, the first punch and the second punch inserted from both ends of the cylindrical die are brought relatively close to each other, and the inside of the cavity formed by the die is formed. Since the powder filled in the cavity is pressed almost equally from both sides to be molded, the powder in the cavity is not washed away in one direction, and the core for molding the side hole when integrally molding the side hole is used. There is no trouble such as bending. Further, since the powder is pressed almost equally from both sides, the density of the molded product does not vary. Therefore, after firing, the molded article does not warp or warp, and cracks and nests do not enter the molded article.

Further, although the powder molding die according to the present invention does not have a pressing force capable of pressing and molding powder, it has a mechanism for adjusting dimensions of other products and a mechanism for discharging products. , Assemble the mold in advance outside the molding equipment,
After making fine adjustments, they can be incorporated into a molding apparatus.
Therefore, even a complicated and fine mold can be assembled and mounted without any restrictions. Furthermore, not only can the setup change such as product type change be performed quickly, but also adjustment work after mounting on the molding apparatus is almost impossible. This is unnecessary, and the operation rate of the device is improved, and the manufacturing cost is reduced.

Further, in the powder molding die and the molding method according to the present invention, the powder is supplied to the cavity while applying fine vibration and is filled, whereby the powder can be quickly filled to every corner in the cavity. You. Therefore, not only the productivity is improved, but the molded product is not chipped, and the quality is improved and stabilized.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view showing one embodiment of a powder molding die according to the present invention.

FIG. 2 is an explanatory sectional view showing a pressing step of the powder molding die shown in FIG.

FIG. 3 is an explanatory sectional view showing a mold opening step of the powder molding die shown in FIG. 1;

FIG. 4 is an explanatory sectional view showing a product removing step of the powder molding die shown in FIG. 1;

FIG. 5 is an explanatory sectional view showing another embodiment of the powder molding die according to the present invention.

FIG. 6 is an explanatory sectional view showing still another embodiment of the powder molding die according to the present invention.

[Explanation of symbols]

10: Die 12: Die plate 14: Upper punch 16: First plate 18, 20: Lower punch 22: Lower core 24, 26, 28: Second plate 30, 32, 34, 36, 72: Block 38: Powder molding Mold 40: Cavities 44, 46, 48, 50, 74, 76: Control cylinder 56: Core 58: Cylinder 60: Guide post 62: Press section 66: Support plate 68: Powder resin 70: Molded product

Claims (8)

[Claims] 1. A die plate which detachably supports a cylindrical die, and a first plate which is operated in the axial direction of the die and individually supports one or a plurality of punches inserted into one end of the die. And at least a second plate group that is driven in the axial direction of the die and individually supports one or a plurality of punches and / or cores inserted into the other end of the die. A powder molding die, which is provided with a block for regulating a distance between the first plate group and the die plate and the second plate group. 2. The apparatus according to claim 1, further comprising: an urging means for urging the die plate and the first plate group and between the die plate and the second plate group in a direction in which respective gaps are separated and approached. The powder molding die according to claim 1. 3. A die plate provided with a hole penetrating a side wall portion of the cylindrical die, a core inserted into the hole, and a cylinder for taking the core into and out of a cavity formed by the die. The powder molding die according to claim 1 or 2, wherein 4. A mounting plate fixed to a mold mounting base of a powder molding apparatus, one or more guide posts erected on the mounting plate and guiding a die plate and the like, and at the other end of the guide post. The powder molding die according to any one of claims 1 to 3, further comprising: a support plate provided with a hole through which a pressing unit of the powder molding device can pass. . 5. The powder molding die according to claim 1, further comprising a vibration generating means for applying fine vibration to the die or the powder filled in the die. 6. A first die inserted from both ends of a cylindrical die.
A powder molding method, comprising: bringing a punch and a second punch relatively close to each other, and pressing a powder filled in a cavity formed by a die substantially equally from both sides to form the powder. 7. The powder molding method according to claim 6, wherein the die is filled with the powder while at least applying micro vibration to the die and / or the powder. 8. A powder molding method characterized in that a die and / or a powder filled in a cavity formed by the die is pressed and molded while applying micro-vibration.