JPH06108105A - Production of die - Google Patents

Abstract

PURPOSE:To enhance the accuracy of the final die by transferring the reference axis set in an inversion model between stages with good accuracy and resetting the three-dimensionally deformed initial reference axis. CONSTITUTION:This method for obtaining the die 12 consists in charging the inversion model 5 having the transfer surface having the shape resembling the shape of a product into a molding flask 1, injecting and pressurizing a slurry prepd. by adding and mixing an org. binder and water or org. solvent to and with metallic powder for sintering into this molding flask 1, discharging the liquid-component in the slurry 8 to form green body 8A solidified via the org. binder by contact of the powder particles with each other and sintering and impregnating this green body 8A. A reference member 11 is mounted to the above-mentioned inversion model 5 and is embedded into the green body 8A. The reference axis is reset on the bases of this reference member 11 after molding of the above-mentioned die 12 and the fitting surface of the insert part of the die 12 is machined on the bases of the above-mentioned reference axis and is fitted into the fitting recessed part of the die base.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold manufacturing method using a metal powder compact.

[0002]

2. Description of the Related Art Plastic injection molding, vacuum molding,
As a method of manufacturing a mold for press molding, blow molding, etc., there is a method of sintering a metal powder to obtain a mold having high strength, high accuracy of smooth surface, and high thermal conductivity. That is, this method
As illustrated in FIG. 9, a reversal model 5 having a transfer surface 5A having a product-similar shape is formed into a molding frame 1 having linear slits 6.
Into the molding frame 1, a slurry 8 made by adding an organic binder and water (or an organic solvent) to a metal powder for sintering is mixed and pressurized, and the liquid in the slurry 8 is added to the slit 6 By discharging from the powder, a green body (metal powder molded body) 8A in which the powder particles are in contact with each other and solidified through the organic binder is prepared.

Next, after the green body 8A is sintered into a sintered body, a metal having a lower melting point than that of the sintered body is infiltrated into the sintered body to complete the molding surface die 12, and The mold 12 is incorporated into a separately manufactured mold base 13. The mold base 13 is made of a mold material other than a sintered body of metal powder, and has a fitting recess larger than that of the molding surface part mold 12, which is an insert part. It is designed to be fitted and fixed to.

[0004]

By the way, in the above prior art, the reference axis (X,
It is necessary to accurately transfer (Y, Z axes) through the mold manufacturing process and use it. Normally, the reference axis set for the reversal model 5 is left as a marking line, but if the marking line is thin during the above manufacturing process, it disappears, and conversely if it is thick, the measurement accuracy decreases and the final mold accuracy also There is a problem of becoming low.

The reference axis set in the reversal model 5 is
There is a problem that it deforms three-dimensionally during the manufacturing process and cannot be used as the reference axis of the insert part. The present invention is
It was made in view of the above-mentioned actual situation, and the purpose thereof is to easily and accurately transfer and leave the reference axis set in the reversal model between the steps, and to deform it three-dimensionally. Another object of the present invention is to provide a mold manufacturing method capable of increasing the accuracy of the final mold by resetting the initial standard shaft and using it as the standard shaft of the insert part (molding surface part mold).

[0006]

In order to achieve the above object, the present invention takes the following technical means. That is, the present invention prepares a reversal model having a transfer surface of a product similar shape in a molding frame, and a slurry obtained by mixing the metal powder for sintering, an organic binder, and water or an organic solvent in the molding frame. After injecting and pressurizing, the liquid content in the slurry is deliquored to bring the powders into contact with each other, and a metal powder molded body solidified via an organic binder is prepared, and the molded body is sintered, and thereafter, In a die manufacturing method for infiltrating a molten metal into a void portion of a sintered body to obtain a molding surface die, during the production of the inversion model, neither end of the X, Y reference axis is altered or deformed between steps. A bottomed cylindrical reference holding member is embedded so that its opening is located on the transfer surface side, processed into a model shape with a straight line connecting the centers of the inner diameters of the respective reference holding members as a reference axis, and after the model is completed, the reference holding member Have a length that is less than twice the internal depth and fit After fitting the connecting pin, the cylindrical holding member with the bottom is fitted onto the molding frame, and when the molded body is separated from the model, the reference holding member is separated from the connecting pin together with the model. Then, the straight line connecting the centers of the reference members embedded in the molding surface portion mold after sintering and infiltration treatment is used as the reference axis,
Measure the contour shape of the shape part of the reference axis cross section of the model and the infiltrated sintered body with a three-dimensional measuring machine, etc., and reset the reference axis of the molding surface mold so that these measurement shapes are the best match. ,
It is characterized in that the insert portion fitting surface of the mold is machined so that it can be fitted into the fitting portion of the mold base.

[0007]

According to the present invention, a reference member is attached to an inverted model, charged into a molding frame, a green body is molded in the same manner as in the conventional case, and the green body in which the reference member is embedded and transferred is sintered. After infiltrating to form a molding surface die, the Z plane and the X and Y reference axes consisting of the plane and the inner diameter center point of the reference member transferred to the molding surface die are set by a three-dimensional measuring machine, To re-set the reference axis by superimposing the measurement data obtained by measuring the cross-sectional contour shape of the shape section and the design data of the cross-section contour shape of the shape section on the X and Y reference axes of the reversal model measured in advance on the same degree mark. According to the reset reference axis, the fitting part of the molding surface part mold can be machined and fitted into the mold base to complete the final mold.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. First, the slurry used in the present invention is formed by mixing metal powder for sintering, an organic binder, and an organic solvent such as water or alcohol. As the metal powder for sintering, various metal powders (Fe, Fe, etc.) produced by the carbonyl method, gas atomizing method, water atomizing method, pulverizing method, etc.
1 type of high speed steel, stainless steel, aluminum, etc., 2
More than one kind of mixed powder can be used. Further, as the metal powder, ceramic powder, mixed powder thereof, or mixed powder of these and various reinforcing fibers can be used.

As the organic binder, one which is soluble in water or an organic solvent which is a slurry liquid is used. For example, acrylic resin type, cellulose acetate type, and thermosetting resin type can be used. The composition of the slurry varies depending on the particle size of the sintering metal powder used, but in general,
2 to 5 parts by weight of binder per 100 parts by weight of metal powder,
Water or organic solvent 8 to 40 parts by weight.

Next, the molding frame 1 used in the present invention is shown in FIG.
As shown in Fig. 5, the reversal model 5 consisting of the outer frame 2, the pressure plunger 3, and the heater 4 (provided as needed), and having the transfer surface 5A of the product-like shape on the inner bottom of the outer frame 2 is charged. The plunger 3 is fitted in the upper opening of the outer frame 2. The outer frame 2 has its side walls appropriately divided in the vertical direction and slits 6 having a slit width S are formed between the opposing divided faces, and also between the outer frame 2 mold surface and the pressure plunger 3. A gap 7 (same as the slit width S) is formed. In addition, the slurry 8 injected and filled in the molding chamber of the molding frame 1 in which the inversion model 5 is charged has a slit of liquid content.
Although it is discharged from 6 and the gap 7, the metal powder remains in the molding chamber.

That is, the slit width S is set to about 3 times or less of the metal powder particle diameter, and the metal particles are set so as to form a bridge and are not discharged from the slit 6 and the gap 7. It is designed to discharge the minute. The reversal model 5 is made of plastic or gypsum, and is manufactured in consideration of shrinkage according to a conventional method according to the product drawing. As shown in FIGS. 3 and 4, both ends of the reference axes X and Y on the transfer surface 5A side are formed. In the vicinity, a stainless steel bottomed cylindrical reference holding member 9 shown in FIG. 5 (for example, outer diameter 14 mm, inner diameter 8 m
m, depth 10 mm) is buried so that the opening is on the transfer surface 5A side and the edge is flush with the transfer surface 5A.

The inverted model 5 is for each reference holding member.
The center of the inner diameter of 9 is used as the reference axes X and Y, and the plane formed by the upper end surface thereof is used as the reference surface for finishing by machining.
A connecting pin 10 is inserted into the reference holding member 9 so that it can be pulled out after the model is finished. The pin 10 is made of stainless steel and has a total length of 19.6 mm, an outer diameter of 5 mm at both ends, and a central part of 2 mm.
The outer diameter of the length range is 8 mm, and the length from the center to the end is
It is molded to be 9.8 mm, and the center part is each reference holding material.
The 9 holes 9A are designed to be fitted and fixed.

Further, the connecting pin 10 has a lid (or bottom).
A reference member 11 having a cylindrical shape and the same size and shape as the reference holding member 9 is externally fitted and fixed, and the inverted model 5 is completed. Next, as shown in Fig. 1, the completed inversion model 5 is the outer frame of the forming frame 1.
The inside of 2 is charged with the same gap S as the slit width S. Then, the slurry 8 mixed and kneaded in another step,
It is injected into the molding frame 1 and pressurized by the pressing of the pressure plunger 3, and the liquid component in the slurry 8 is discharged from the slits 6 and the gaps 7 of the molding frame 1. The pressure of the slurry 8 was 20 kg: f / cm ² , and the entire molding frame 1 was pressed at 10 kg.
Heated to 0 ° C.

The slurry 8 is dewatered under pressure until the metal powders come into contact with each other, the binder in the solvent is concentrated or solidified by the disappearance of the liquid content, and the metal powders are solidified via the binder, and the green body 8A. (Metal powder compact) is formed, and the reference member 11 is embedded in the green body 8A (see FIG. 5B). When the green body 8A is taken out from the molding frame 1 and the inverted model 5 is separated, the reference holding member
9 and the inverted model 5 slipped out from the connecting pin 10,
As shown in (c) and FIGS. 6 and 7, the reference member 11 is embedded in the green body 8A, and the reference holding member 9 on the inverted model 5 side and the reference member 11 on the green body 8A side are both displaced. The reference axis of the reversal model 5 is accurately transferred to the green body 8A via both members 9 and 11 because it is not embedded.

The green body 8A is dried in a sintering furnace 13
After sintering for 1 hour at 00 ℃, the sintered body is 1200 ℃ in molten Cu.
It is dipped under the condition of × 4 hours and the molten Cu is infiltrated into the pores of the sintered body to form the molding surface die 12. The reference member 11 is not deformed by the sintering / infiltration treatment of the green body 8A, and the initially set reference axis is accurately transferred to the infiltration treated body in the final step, that is, the die 12.

Molding surface portion mold 12 molded in this way
The reference axis is reset as shown in FIG. In addition,
Although FIG. 8 shows data based on the X and Z axes, data is similarly measured for the Y and Z axes and the reference axis is reset. First, design data D1 in which the cross-sectional contour shape of the shape part on the X and Y reference axes of the inversion model 5 is measured in advance by using a three-dimensional measuring machine is prepared (see FIG. 8A). On the other hand, the plane consisting of four upper end surfaces of each reference member 11 of the mold 12 and the Z plane consisting of the center point of the inner diameter of the reference member 11 and the X and Y reference axes are set by a three-dimensional measuring machine, and on the axes. The profile contour of the shape part is measured to obtain measurement data D2 (see FIG. 8B).

Next, as shown in FIG. 8C, the design data D1 and the measurement data D2 are superimposed on the same coordinate, and both data D
The design data D1 is moved in the X-, Y-, and Z-axis directions so that the difference between the shape portions of 1 and D2 is minimized, that is, the shape contours match (see FIG. 8D). The position thus moved is reset as a new reference axis. Therefore, the fitting surface of the molding surface mold 12 which is the infiltrated sintered body to the mold base 13
(That is, the fitting surface of the insert portion) is machined and finished by the reset reference axis to complete the molding surface portion die 12.

Molding surface portion mold 12 completed in this way
Is assembled in a recess of the mold base 13 together with the mold other than the molding surface, and the final mold 14 is completed.

[0019]

As described above, according to the present invention, a reversal model having a transfer surface having a similar product shape is charged in a molding frame, and the metal powder for sintering, an organic binder and water or an organic solvent are charged in the molding frame. Inject and pressurize the slurry that is mixed with
After removing the liquid in the slurry and bringing the powders into contact with each other, a metal powder compact solidified via an organic binder is prepared, and the compact is sintered, and then the pores of the sintered compact are formed. In a mold manufacturing method for infiltrating molten metal into a mold to obtain a molding surface mold, a bottomed cylindrical reference that does not change or deform between steps at both ends of the X and Y reference axes when the inverted model is manufactured. The holding member is embedded so that its opening is located on the transfer surface side, processed into a model shape with the straight line connecting the inner diameter centers of the respective reference holding members as the reference axis, and after the model is completed, it is twice the internal depth of the reference holding member. After fitting a connecting pin that has the following length and fits, and then insert the bottomed cylindrical reference member into the molding frame with the pin fitted to the molding frame to separate the molded body from the model. The reference holding member is separated from the connecting pin together with the model, and sintered and infiltrated. Using the straight line connecting the centers of the reference members embedded in the molding surface part of the mold as the reference axis, measure the contour shape of the model and the reference axis cross section of the infiltrated sintered body with a three-dimensional measuring machine, etc. , It is possible to reset the reference axis of the molding surface part mold so that these measured shapes best match, and machine the insert part fitting surface of the mold to fit the fitting part of the mold base. It is characterized by doing so,
The reference axis initially set from the molding transfer process to the sintering and infiltration process can be accurately left in the molding surface die (infiltrated sintered body).

Also, the three-dimensionally deformed initial reference axis can be reset based on the most important shape processing part as a reference, and the one with the highest accuracy as the reference axis of the molding surface part die which is the insert part. It is possible to improve the accuracy of the final mold.

[Brief description of drawings]

FIG. 1 is a flow chart of the present invention.

FIG. 2 is a vertical cross-sectional side view showing an example of a molding frame used for carrying out the present invention.

FIG. 3 is a plan view showing an example of an inversion model.

FIG. 4 is a vertical sectional view taken along the X-axis line of FIG.

5 (a) and 5 (b) are explanatory views of a transfer situation of a reference axis.

FIG. 6 is a plan view of a green body.

FIG. 7 is a vertical cross-sectional view taken along the X-axis line of FIG.

8 (a) to 8 (e) are explanatory views of a basic axis resetting procedure of the shape surface part mold.

FIG. 9 is a flowchart of a conventional example.

[Explanation of symbols]

 1 Molding frame 5 Inversion model 5A Transfer surface 8 Slurry 8A Green body (metal powder molded body) 9 Reference holding member 10 Connecting pin 11 Reference member 12 Molding surface mold (infiltrated sintered body) 13 Mold base

Claims (1)

[Claims] 1. A reversal model having a transfer surface of a similar product shape is placed in a molding frame, and a slurry formed by mixing a metal powder for sintering, an organic binder, and water or an organic solvent is injected into the molding frame. Then, the liquid in the slurry is deliquored to bring the powders into contact with each other, and a metal powder molded body solidified through an organic binder is prepared, and the molded body is sintered and then baked. In a mold manufacturing method for infiltrating a molten metal into a hole of a united body to obtain a mold for a molding surface part, when manufacturing the inversion model, both ends of the X and Y reference axes are not deteriorated or deformed between processes. The bottom cylindrical reference holding member is embedded so that its opening is located on the transfer surface side, processed into a model shape with the straight line connecting the inner diameter centers of each reference holding member as the reference axis, and after the model is completed, inside the reference holding member Has a length less than twice the depth and fits After fitting the connecting pin, the reference member having a bottomed cylindrical shape is fitted onto the pin and placed in a molding frame, and when the molded body is separated from the model, the reference holding member is separated from the connecting pin together with the model. After the sintering and infiltration treatment, the straight line connecting the centers of the reference members embedded in the mold is used as the reference axis, and the contour shape of the model and the shape of the reference axis cross section of the infiltrated sintered body are set. Measure with a three-dimensional measuring machine, etc., reset the reference axis of the molding surface part mold so that these measurement shapes best match, machine the insert part fitting surface of the mold, and A mold manufacturing method, characterized in that it can be fitted into a fitting portion.