JP2003183705A - Production method for powder-sintered molded article, powder-sintered molded article, production method for powder injection molded article, powder injection molded article, and metal mold for powder injection molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a powder-sintered molded article whereby the problems with handling a powder injection molded article are solved, even an injection molded article with a complicated shape can be easily demolded, and a plurality of articles can be simultaneously molded and easily handled. <P>SOLUTION: An additional molding material which changes into a form removable or separable from a sinterable-material molded article at a degreasing or sintering step is injected into a metal mold having an additional mold section, thus forming an additional molded part 5 integrally with the sinterable-material molded item 7. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a powder sintered compact and the like. More specifically, the present invention relates to a method for manufacturing a powder sintered compact, which includes a sintering material molding step of injecting a sintering material containing a bun ida and sinterable powder into a mold.

[0002]

2. Description of the Related Art A powder injection molding method comprises a sintering material molding step in which a powder of metal or the like is heated and mixed with a resin binder or the like so as to have fluidity, and this is injection-molded to produce a molded body. The method includes a degreasing step of heating the molded body to remove the resin binder, and then a sintering step of heating to a higher temperature to sinter the powder. When using metal as powder, MIM method (METAL POWDE
R INJECTION MOLDING), and is widely used for manufacturing metal parts having a complicated shape.

[0003]

In the powder injection molding method, an injection molding machine similar to that used for molding plastics is used, but the proportion of the sintered powder added is larger than that of the resin binder. The strength of the injection molded body as an intermediate is lower than that of a normal resin molded product. Particularly, in the powder injection molding method, since the degreasing step and the sintering step have to be performed after the injection molding, the handling during that time often becomes a problem. For example, a problem that an injection-molded body having a complicated shape is damaged during the next process is likely to occur.

Further, since the strength of the injection-molded article is weak, it is often damaged when it is released from the mold. In particular, it is difficult to release a molded product having a complicated shape or a small molded product from the mold.

Further, in ordinary resin injection molding, when molding a small molded product, it is often the case that a plurality of molded products are molded in one injection step via a runner or the like. However, in the powder injection molding method, since the strength of the injection molded body is low as described above, when a lot of products are injection-molded at once by providing a runner or the like, it becomes very difficult to release from the mold. . Further, since the strength of the connecting portion such as the runner is low, it is difficult to integrally handle a plurality of molded products connected in series through the runner and the like like a resin injection molded product. Therefore, the production efficiency of forming a product having a small and complicated shape by the powder injection molding method is very low.

In recent years, the LIGA process (Lithogr
aphie Galvanoformung Abfo
Attempts have been made to manufacture a so-called micromachine or the like by injection-molding a resin using a mold formed by rmung). However, for the above reasons, it has been very difficult to manufacture a micromachine from a powder injection molding containing metal or ceramic.

The present invention has been devised under the circumstances described above. It solves the above-mentioned problems of the prior art, solves the problem of handling of powder injection moldings, and injection-molds complicated shapes. Even in such a case, the present invention provides a method for producing a powder sintered compact which can be easily released from the mold and can be easily handled by simultaneously molding a plurality of products.

[0008]

In order to solve the above problems, the present invention takes the following technical means.

The invention described in claim 1 of the present application is a sintering material molding step of injecting a sintering material containing a vandal and sinterable powder into a mold provided with a sintering material molding die part. And a degreasing step of removing the vanida from the sintered material compact obtained in the sintered material compacting step, and a sintering step of sintering the sintered material compact having undergone the degreasing step to form a sintered compact. A method for producing a powder sinter compact comprising: an additional mold material that is removed from the sinter material compact in the degreasing step or the sintering step or is changed into a separable form, It includes an additional molding step of injecting into a provided mold and molding an additional molding portion integrated with the sintered material compact.

The method for producing a powder sintered compact according to the present invention comprises a plurality of molding steps of injecting at least two kinds of molding materials into a mold. The injection molding machine used in the present invention may be configured so that at least two types of molding materials can be continuously or intermittently injected into a set of molds. It is also possible to move the mold between a plurality of injection moldings and continuously perform a plurality of injection molding processes. Further, a thermoplastic resin binder may be adopted for hot injection molding, or a water-based resin binder may be adopted for cold injection molding.

Further, the sintered material compact can be formed by a plurality of injection molding steps, and the addition generating part can be formed by a plurality of injection molding steps. In order to perform the plurality of injection molding steps, a mold that can sequentially provide a plurality of molding die parts is used.

Further, in the injection molded body according to the present invention, a sintered material molded body containing sintered powder and an additional molded portion containing no sintered powder are integrally formed. The sintered material compact and the additional molding part may be formed of a single molding material, or may be formed of a plurality of kinds of molding materials.

The purpose of providing the additional molding part is not particularly limited.

For example, by providing the additional molding portion, it becomes possible to protect the sintering material molding portion when the molded body is released from the mold. Molding so as to cover the part that is difficult to release or the part having a complicated shape with the additional forming part can prevent the above-mentioned part from being damaged during the release.

In particular, in the case of injection molding a minute molded product, if the runner and the like are formed so as to be embedded in the additional molding portion, the molded product and the runner and the like can be easily and integrally released from the mold. Further, it becomes possible to remove the runner and the like integrally with the additional molding portion before the degreasing step. Therefore, the production efficiency of minute molded products can be significantly improved.

When the molded product is conveyed after being released from the mold, it can be handled in the same manner as a conventional resin molded product. For example, if the sintered material molded part is formed so as to be embedded in the additional molded part, the sintered material molded part is not likely to be scratched, the handling property of the injection molded body is significantly improved, and defective products are generated. Can be prevented.

Further, an additional molding portion is provided for the purpose of positioning the injection molded body during secondary processing before the degreasing process, or a plurality of sintered material molded bodies are integrated through the additional molding portion. It can also be provided for the purpose of

Further, it can be used to maintain the shape of the sintered compact during the degreasing process and the sintering process. Furthermore, a material having a high heat insulating property can be formed for the purpose of enhancing the formability of the sintered material.

The portion where the additional molding portion is provided is not particularly limited, either, and it may be formed so as to cover the entire surface of the sintered material molding, or may be formed so as to cover a part thereof. It is also possible to form the sintered material compact in a form in which the concave portion or the hollow portion is filled with an additional molding material.

Since the additional molding part is removed or separated from the sintered material compact in the degreasing step or the sintering step, it does not adversely affect the sintered material compact part.

The sintered material according to the present invention can be configured to include a bun rider and sinterable powder, like the conventional powder injection molding material. The types of the above-mentioned bainda and the above-mentioned sinterable powder are not particularly limited. For example, as in the invention described in claim 4, metal powder or ceramic powder can be adopted as the sinterable powder.

On the other hand, the additional molding material is configured so as to be removed or separated from the sintered material compact in the degreasing step or the sintering step. As the additional molding material, as in the invention described in claim 5, the additional molding material can be configured to include the above-mentioned van-ida or the main component of the above-mentioned van-ida included in the above-mentioned sintered material. The resin material used as the binder can be used as it is. As a result, it becomes possible to easily remove it in the degreasing step, like the van rid in the sintered material compact.

By forming the additional molding portion with a resin material having a higher heat insulating property than the mold, it is possible to mitigate the temperature decrease during injection molding of the sintered material. As a result, the fluidity in the mold is improved, and a highly accurate injection molded product can be formed.

As the above-mentioned additional molding material, as in the invention described in claim 6, a powder which is not sintered in the above-mentioned sintering step can be included. For example, while the sintered material compact is configured to include metal powder, ceramic powder can be used as the powder that does not sinter.

Generally, the sintering temperature of ceramics is higher than the sintering temperature of metals. Therefore, when an injection-molded body formed of the above-mentioned material is sintered at a temperature at which the metal powder sinters, the additional molding portion becomes powdered or sandy and easily separated from the sintered molded body. Can be made. Further, since the sintering step is performed so that the sintered compact is embedded in the ceramic powder, it is possible to exert the effect of preventing deformation of the sintered compact in the sintering step. Particularly, the effect is high when the degreasing step and the sintering step are continuously performed.

According to a seventh aspect of the present invention, the sintering material and the additional molding material are formed of materials which are incompatible with each other. For example, the additional molding material may be formed of a resin material that is incompatible with the resin binder included in the sintered material.

The additional molding portion is later removed or separated from the sintered material compact. Therefore, by selecting a material having no compatibility in the injection molding step, the surface accuracy of the sintered compact can be improved. For example, polyacetal resin (POM) can be adopted as the binder of the sintering material, while acrylic resin (PMMA) can be adopted as the additional molding material.

In the present invention, as in the invention described in claim 2 or 3, either of the sintering material forming step and the additional forming step may be performed first.

The invention described in claim 2 of the present application is a method for producing a powder sintered compact, wherein the above-mentioned additional molding step is performed before the above-mentioned sintered material molding step, wherein the above-mentioned sintered material is added to the above-mentioned additional molding part. Forming a mold part that constitutes a part or all of the molding mold part,
The sintering material molding step is performed by injecting the sintering material into a mold provided with a sintering material molding die portion including the molding portion.

In the invention described in claim 2, first, the additional molding portion is injection-molded to form a mold of a portion continuous with the sintered material, and then the sintering material is injected to mold the additional molding portion. To be integrated with. The mold part formed in the additional molding part may correspond to a part of the sintered material compact or may correspond to the whole.
In the case of supporting all of them, the injection molded body is formed so that the sintered material injection molded body is embedded in the additional molding portion.

On the other hand, the invention described in claim 3 of the present application is
A method for producing a powder sintered compact, which comprises performing the above-mentioned additional molding step after the above-mentioned sintering material molding step, wherein a mold part constituting a part or all of the above-mentioned additional mold part is formed in the above-mentioned sintered material compact. Then, the above-mentioned additional molding step is performed by injecting the above-mentioned additional molding material into a mold provided with an additional mold section including the above-mentioned mold section.

In the invention described in this claim, first, the sintered material compact is formed, and then the additional molded portion is provided by using a part or all of this sintered material compact as a mold. . The portion where the additional molding portion is provided is not limited, and it may be formed in a part of the periphery of the sintered material compact or may be formed so as to cover the entire periphery of the sintered material compact. it can. Further, when the sintered material compact is hollow, the hollow part may be set as an additional molding die and filled with the additional molding material.

The invention described in claim 8 of the present application relates to a powder sintered compact formed by the manufacturing method described in claims 1 to 7. According to the invention described in claims 1 to 7, it becomes possible to efficiently manufacture a powder sintered body product having a shape that could not be manufactured conventionally.

The invention described in claims 9 to 13 of the present application relates to a method for producing a powder injection molded article.

According to a ninth aspect of the present invention, a sintering material containing a sinterable powder and a vanida that can be removed in a degreasing step is injected into a mold provided with a sintering material molding die part. A sintering material forming step of forming a sintered material forming body, and an addition forming material which is removed from the sintering material forming body or is changed into a separable form in the degreasing step or the sintering step. An additional molding step of forming an additional molding portion by injecting into a mold provided with a portion, the sintered material molded body and the additional molding portion are integrally molded in the mold, The present invention relates to a method for manufacturing a powder injection molded body.

In the method of manufacturing a powder injection molded article according to the present invention, the sintered material molding part and the additional molding part are integrally molded. The powder injection molded product formed by this method is
High strength and easy handling. Moreover, it becomes possible to easily perform secondary processing as an intermediate product.

According to a tenth aspect of the present invention, in the additional molding step, a mold part corresponding to a part or all of the sintering material molding mold part is formed in the additional molding part, and the mold part is formed. The sintering material molding step is performed by injecting the above-mentioned sintering material into a mold provided with a sintering material molding die portion including the above.

According to an eleventh aspect of the present invention, in the sintering material molding step, a mold portion corresponding to a part or all of the additional molding die portion is formed in the sintering material molding die, and The above-mentioned additional molding step is performed by injecting the above-mentioned additional molding material into a mold provided with an additional mold section including a mold section.

According to the twelfth aspect of the present invention, the additional molding material contains a powder that does not sinter at the sintering temperature of the sintering material.

According to a thirteenth aspect of the present invention, a metal powder or a ceramic powder is adopted as the sinterable powder.

The invention described in claims 14 to 17 of the present application relates to a powder injection molded article.

According to a fourteenth aspect of the present invention, there is provided a sintered material compact formed from a sintered material containing sinterable powder and Banida that can be removed in the degreasing step, and the degreasing step or the sintering step. The present invention relates to a powder injection molded body in which an additional molding portion formed of an additional molding material that is removed from the above-mentioned sintered material molded body or changed into a separable form in the step is integrally molded.

According to a fifteenth aspect of the present invention, the additional molding portion is formed so as to cover a part or all of the surface of the sintered material compact.

According to a sixteenth aspect of the present invention, the additional molding material contains a powder that does not sinter at the sintering temperature of the sintering material.

According to a seventeenth aspect of the present invention, a metal powder or a ceramic powder is adopted as the sinterable powder.

The invention as set forth in claim 18 of the present application is a sintering material molding die for molding a sintering material compact by injecting a sintering material containing a sinterable powder and a vanida which can be removed in a degreasing step. And an additional molding die for molding the additional molding part by injecting an additional molding material that is removed from the sintered material compact or is changed into a separable form in the degreasing step or the sintering step. The present invention relates to a powder injection molding die configured so that each die part can be sequentially formed in the die.

The mold comprises a plurality of mold members,
The sintered material molding die can be formed in the sintered material molding step, and the additional mold portion can be molded in the additional molding step. The mold may be configured such that either the sintering material forming step or the additional forming step is performed first.

According to a nineteenth aspect of the present invention, a part or all of the sintered material molding die portion and / or the additional molding die portion is formed by a LIGA process.

The LIGA process is a processing method suitable for forming a minute mold, and by adopting the upper mold, minute parts such as micromachines can be molded with high precision and efficiency. It will be possible.

[0050]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be specifically described below with reference to the drawings.

1 to 6 show a first embodiment of the present invention.

In this embodiment, a sintering material containing a stainless steel powder and a polyacetal resin binder is adopted, while a polyacetal resin which is the main component of the resin binder is adopted as the additional molding material. is doing.

FIG. 1 shows an outline of a mold 1 used for manufacturing a powder sintered compact according to the present invention. In the present embodiment, the present invention is applied to the case where the bottomed stepped cylindrical body shown in FIGS. 5 and 6 is formed.

In this embodiment, the mold 1 is composed of one lower mold 2 and two upper molds 3 and 4 which are sequentially combined with the one lower mold 2. By sequentially combining the lower mold 2 and the upper molds 3 and 4, two injection spaces for injection filling the injection molding material are sequentially formed. The injection molded body according to the present invention is formed by sequentially injecting the molding material into the two injection molding spaces by a biaxial injection molding machine or the like.

As shown in FIG. 2, by combining the lower mold 2 and the upper mold 3, an additional mold part 6 for molding the additional molding part 5 is constructed. On the other hand, as shown in FIG. 3, by combining the lower mold 2 and the upper mold 4, a sintered material molding die portion 8 for molding the sintered material molding 7 is configured. The upper mold 3 has an additional molding material 9
A gate 10 for injecting Also,
The upper mold 4 is provided with a gate 12 for injecting the sintered material 11.

A method of manufacturing the powder sintered compact according to the present embodiment will be specifically described with reference to FIGS. 2 to 6 and FIG.

In the present embodiment, as shown in FIG. 2, first, the lower mold 2 and the upper mold 3 are combined to form the additional mold section 6 (S101). The lower mold 2 is formed with a mold 13 having a cylindrical inner surface. On the other hand, the upper mold 3 is formed with a stepped cylindrical mold part 14 corresponding to the shape of the outer peripheral part of the sintered material compact. By injecting the additional molding material 9 into the additional material injection molding space formed by the lower mold 2 and the upper mold 3, the outer peripheral part has a stepless cylindrical shape, while the inner upper part is burnt. Binder molding 7
The additional molding part 5 including the stepped concave mold part 15 corresponding to the outer peripheral part of the is formed (S102).

After molding the additional molding portion 5, the upper mold 3 is replaced with the upper mold 4. The upper die 4 is provided with a stepped cylindrical die portion 16 having a shape corresponding to the shape of the inner peripheral portion of the sintered material compact 7. The sintered material molding die portion 8 formed by the concave die portion 15 of the additional molding portion 5 and the die portion 16 of the upper die 4 constitutes a sintered material injection molding space for filling the sintering material 11. (S103). Then, by injecting the sintered material 11 into the sintered material injection molding space, the additional molding portion 5 and the sintered material molding are molded in the mold 1 constituted by the lower mold 2 and the upper mold 4. An injection molded body 17 integrated with the body 7 is formed (S10).
4).

In this embodiment, since the additional molding portion 5 is made of a resin material, the sintering material molding die portion 8 is formed.
The heat insulation of is increasing. Therefore, the fluidity when the sintered material is injected does not decrease, and the sintered material compact 7 with high accuracy can be formed.

Next, the injection molded body 17 is released from the mold (S105). The sintered material compact 7 has a low strength because it contains a large amount of powder. Therefore, the corners and the like are likely to be damaged when the mold is released with the stepped cylindrical shape. In the present embodiment, as shown in FIG. 4, the injection molded body 17 is integrally formed with the additional molded portion 6 so as to cover the outer peripheral portion of the sintered material molded body 7. There is no risk of damaging the corners.

Next, the injection molded body 17 is conveyed to a degreasing furnace and a degreasing process is performed (S106). In the present embodiment, since the outer peripheral portion of the sintered material compact 7 can be protected even when it is conveyed to the degreasing furnace after being released from the mold, handling becomes extremely easy. Therefore, the yield is significantly improved.

The additional molding portion 5 according to this embodiment is formed of the same resin material as the resin binder used for the above-mentioned sintering material. Therefore, in the degreasing step, the additional forming part 5 can be removed from the sintered material compact at the same time as the resin binder contained in the sintered material.

After removing the resin binder and the additional molding portion in the degreasing step, a sintering step is performed (S10).
7). The degreasing step and the sintering step may be continuously performed in the same furnace. By performing the above sintering step,
The powder sintered compact 18 is formed (S108).

7 to 12 show the second embodiment of the present invention. In this embodiment, the present invention is applied to the case where a plurality of sintered material compacts 7 according to the first embodiment are simultaneously injection-molded.

As shown in FIGS. 7 and 8, the mold 21 according to the present embodiment has one lower mold 22 and one lower mold 22 sequentially combined in the same manner as in the first embodiment. And two upper molds 23 and 24 that are connected to each other. The lower mold 22 is provided with a gate 30 for injecting the additional molding material 29. On the other hand, the upper mold 24 is provided with a pair of gates 32, 32 for injecting the sintered material 31.

A method of manufacturing the powder sintered body according to the present embodiment will be specifically described with reference to FIGS. 7 to 12, 13 and 14. Note that steps 101 to 105 in FIG. 13 are performed in the same procedure as in the first embodiment.

As shown in FIG. 7, in the present embodiment, first, the lower die 22 and the upper die 23 are combined to form an additional die portion 26 (S101). The lower die 22 is formed with a concave die portion 33 having a square inner surface.
On the other hand, the upper mold 23 is provided with a mold part 34 having a plurality of stepped columnar convex parts corresponding to the outer peripheral shapes of the plurality of sintered material compacts 27, and the mold part 33 and the mold part 34 are formed. Part 3
The additional mold part 26 is configured by combining 4 and 4. By injecting the additional material 29 into the additional molding space formed by the lower mold 22 and the upper mold 23,
While the outer peripheral part has a rectangular parallelepiped shape, the additional molding part 25 having the concave mold parts 35 corresponding to the outer peripheral parts of the plurality of sintered material compacts 7 is formed in the inner upper part (S102).

After molding the additional molding portion 25, the upper mold 23 is replaced with the upper mold 24. In the upper mold 24,
As shown in FIG. 8, a plurality of stepped cylindrical mold parts 36 having a shape corresponding to the shape of the inner peripheral part of each sintered material compact 27 and a runner mold part 38 connecting the mold parts 36 are formed. ing.
The sintering material molding die portion 28 formed by the concave die portion 35 of the additional molding portion 25 and the die portion 36 of the upper die 24 constitutes a sintering material injection space for filling the sintering material 31 ( S103). Then, the sintered material 31 is injected into the sintered material injection space through the runner mold portion 38.
As a result, as shown in FIG. 10, an injection molded body 37 in which the additional molded portion 25, the plurality of sintered material molded bodies 27, and the runner portion 39 are integrated is formed in the mold 21 (S).
104).

Next, the injection molded body 37 is released from the mold 1 (S105). The above-mentioned sintered material compact 27 has a low strength because of the large proportion of powder. Moreover, the runner portion 39 is thinner and has a lower strength than the sintered material compact 27. Therefore, it is very difficult to separate the sintered material compact from the mold if the runner portion 39 is still attached. As shown in FIGS. 9 and 10, in the injection molded body 37 according to the present embodiment, the additional molded portion 25 is integrally formed so as to cover the outer peripheral portion of the sintered material molded body 27. While protecting the sintered material compact 27 and the runner portion 39,
It can be released very easily. In the embodiment, the lower surface of the runner 39 is formed so as to be attached to the surface of the additional molding portion, but the entire runner 39 may be formed so as to be embedded in the additional molding portion 25.

In the embodiment, the runner portion 39 of the injection molded body 37 is formed so as to protrude from the upper surface of the rectangular parallelepiped additional molded portion 25, as shown in FIGS. 9 and 10. Therefore, as shown in FIG. 11, only the runner portion 39 can be easily removed by machining after injection molding (S201). After degreasing and sintering after removing the runner portion 39 (S202 and S203), a plurality of sintered compacts 40 shown in FIG. 12 are formed (S20).
4).

Further, even when the sintered material compact 7 is conveyed to the degreasing and sintering furnace after being released from the mold, the outer peripheral portion of the sintered material compact 7 can be protected by the additional compacting portion 25, so that the handling becomes extremely easy. In addition, as described above, the runner portion 39 can be easily removed.

Further, in the present embodiment, since the plurality of sintered material compacts are regularly arranged, it is possible to easily carry out the secondary processing such as drilling before the degreasing step. Therefore, not only the yield is remarkably improved, but also the production efficiency can be remarkably improved.

FIG. 15 shows a flowchart according to the third embodiment of the present invention.

In this embodiment, step 10 in FIG. 13 is used.
After step 5, steps 301 to 305 are performed.

In this embodiment, the degreasing step (S301) and the sintering step (S30) are performed with the runner part attached.
Perform 2). Since the plurality of molded bodies are regularly connected via the runner portion, it is possible to efficiently perform secondary processing such as drilling and plating. The runner portion is removed by machining before or after the secondary processing.

FIG. 16 shows a flowchart according to the fourth embodiment of the present invention.

In this embodiment, step 101 in FIG. 13 is used.
From step 401 to step 408, steps 401 to 408 are performed.

Incidentally, from step 405 to FIG. 14 or FIG.
It is also possible to shift to the steps of the flowchart shown in FIG.

The additional molding portion of the injection molded body shown in FIG. 4 can be molded after molding the sintered material molded body depending on the shape and purpose. In the present embodiment, first, a sintering material injection space is formed (S401), and the sintering material is injected (S4).
02), and then molding the additional molding space (S40
3), the additional material is injected (S404).

For example, although the injection-molded article has a simple shape, it is suitable for molding a positioning portion or the like for performing complicated secondary processing before the degreasing step.

17 and 18 show a fifth embodiment of the present invention.

As shown in FIG. 17, in the present embodiment, similarly to the first embodiment, the sintered material is composed of metal powder and a resin binder removed in the degreasing step. On the other hand, the additional molding material includes the resin binder and the ceramic powder 43 which is not sintered at the sintering temperature of the metal powder.

In this embodiment, only the components of the additional molding part are different, and the injection molding process, the degreasing process and the sintering process are performed in the same manner as in the above-mentioned embodiment, and therefore the description thereof is omitted. Further, in order to explain the operation, the size of the ceramic powder 43 is expressed in a visible size, but the particle size of the ceramic powder depends on the shape, material, purpose, etc. of the sintered compact. It may be set accordingly, and is not particularly limited.

The injection molded body 57 shown in FIG. 17 has a rectangular additional molding portion 45 containing the ceramic powder 43, and a plurality of sintered material molded bodies 47 as in the second embodiment shown in FIG. Are formed so as to be embedded. Further, by providing the additional molding portion 45 integrally with the sintered material molded body 47, it is possible to protect the sintered material molded body and improve the releasability, handling property, etc. It is similar to the form.

On the other hand, since the additional molding part 45 includes the powder 43 which does not sinter at the sintering temperature of the metal powder, when the resin binder is removed in the degreasing step or the sintering step, As shown in 18, deformed like sand,
Degreased sintered material compact or sintered compact 4
8 changes to a form that can be easily removed.

As shown in FIG. 18, when the injection molded body is placed on the floor surface 42 of the degreasing furnace or the sintering furnace and the degreasing process or the sintering process is performed, the sintered molded body 48 becomes the ceramic powder. It is degreased or sintered so that it is buried in the body. Therefore, in the degreasing step or the sintering step, the effect of preventing the deformation of the sintered material compact can be exerted.

In addition, in either the degreasing step or the sintering step, the shape retention of the ceramic powder in the additional molding portion may be lost. In particular, when performing the degreasing step and the sintering step in succession, etc., in one step or both steps,
The ceramic powder may be sanded.

The present invention is not limited to the above embodiment. The composition, shape, etc. of the sintered material compact and the additional molded part are not limited to those in the embodiment, and various compositions and forms can be adopted.

Although metal powder is used as the sintering material, other sinterable powder such as ceramic powder can be used.

Further, in the embodiment, the resin binder constituting the sintered material compact is adopted as the additional molding material, but other resin materials can be adopted. For example,
In order to improve the surface accuracy and the like of the sintered material compact, it is possible to employ a resin material that is incompatible with the resin binder contained in the sintered material compact.

Further, in the embodiment, the additional molding portion and the sintered material molding are each formed by one injection molding, but they may be formed by a plurality of injection molding processes.

Further, in the embodiment, the additional molding portion and the sintered material compact were each formed of one kind of material, but they may be formed of a plurality of materials by a plurality of injection molding processes.

Although the present invention is applied to the hot injection molding method in the present invention, the present invention can also be applied to the cold injection molding method using the water-based binder.

[Brief description of drawings]

FIG. 1 is a sectional view of a mold for forming an injection-molded article according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a state where an additional molding portion is molded by the mold shown in FIG.

FIG. 3 is a cross-sectional view showing a state where a sintered material compact is molded by the mold shown in FIG.

FIG. 4 is a cross-sectional view of an injection molded body molded by the mold of FIGS. 2 and 3.

5 is a cross-sectional view of a powder sintered compact formed by degreasing and sintering the injection molded body shown in FIG.

FIG. 6 is a perspective view of the powder sintered compact shown in FIG.

FIG. 7 is a diagram showing a state in which an additional molding portion of the injection-molded article according to the second embodiment of the present invention is injection-molded.
It is a sectional view corresponding to.

FIG. 8 is a view showing a state where a sintered material compact of a powder injection molded article according to the second embodiment of the present invention is injection-molded, and is a cross-sectional view corresponding to FIG. 3.

9 is a cross-sectional view of an injection-molded body manufactured by the steps of FIGS. 7 and 8. FIG.

10 is a perspective view of the injection-molded body shown in FIG.

11 is a perspective view showing a state where the injection molded body shown in FIG. 10 is subjected to secondary processing to remove the runner portion.

12 is a perspective view of a powder sintered compact obtained by degreasing and sintering the injection molded body shown in FIG.

FIG. 13 is a flowchart showing a procedure of a method for manufacturing a powder sintered compact according to the first embodiment.

FIG. 14 is a flowchart showing a part of a procedure of a method for manufacturing a powder sintered compact according to a second embodiment.

FIG. 15 is a flowchart showing a part of a procedure of a method for manufacturing a powder sintered compact according to a fourth embodiment.

FIG. 16 is a flowchart showing a part of a procedure of a method for manufacturing a powder sintered compact according to a fifth embodiment.

FIG. 17 is a sectional view of an injection-molded article according to a sixth embodiment.

18 is a cross-sectional view showing a state where the injection molded body shown in FIG. 17 is degreased and sintered.

[Explanation of symbols] 1 mold 5 Additional molding section 7 Sintered material compact 8 Sintered material molding die 11 Sintered material

Claims (19)

[Claims] 1. A sinter material molding step of injecting a sinter material containing a binder and a sinterable powder into a mold provided with a sinter material molding die part; A powder sintered compact including a degreasing step of removing the vanida from the obtained sintered material compact and a sintering step of sintering the sintered material compact that has undergone the degreasing step to form a sintered compact. A manufacturing method, wherein an additional molding material that is removed from the sintered material compact in the degreasing step or the sintering step or changes into a separable form is injected into a mold provided with an additional mold part. A method for producing a powder sintered compact, including an additional molding step of molding an additional molding portion integral with the above-mentioned sintered material compact. 2. A method for manufacturing a powder sinter molded body, wherein the additional molding step is performed before the sintering material molding step, wherein a part or all of the sintering material molding die section is added to the additional molding section. The sintering material forming step is performed by injecting the sintering material into a mold that forms a forming die portion and that is provided with a sintering material forming die portion that includes the forming portion. Item 2. A method for producing a powder sintered compact according to Item 1. 3. A method for producing a powder sintered compact, which comprises performing the additional compaction step after the sintering material compaction step, wherein a part or all of the additional mold part is formed in the sintered material compact. The powder according to claim 1, wherein the additional molding step is performed by injecting the additional molding material into a mold that forms a molding section that includes the additional molding section including the molding section. Method for producing sintered compact. 4. The method for producing a powder sintered compact according to claim 1, wherein the sinterable powder is a metal powder or a ceramic powder. 5. The powder sintering process according to claim 1, wherein the additional molding material is configured to include the bainida or a main component of the bainida contained in the sintering material. Form manufacturing method. 6. The method for producing a powder sintered compact according to claim 1, wherein the additional molding material contains a powder that does not sinter in the sintering step. 7. The sintering material and the additional molding material,
The method for producing a powder sintered compact according to any one of claims 1 to 4, which is formed of materials which are incompatible with each other. 8. A powder-sintered compact formed by the manufacturing method according to claim 1. 9. A sintered material compact is obtained by injecting a sintered material containing a sinterable powder and a vanida removable in a degreasing step into a mold provided with a sintered material molding die part. The sintering material forming step to be formed and the additional molding material which is removed from the sintered material forming body or changed into a separable form in the degreasing step or the sintering step are injected into a mold provided with an addition die section. And an additional molding step of forming an additional molding section, whereby the sintered material molded body and the additional molding section are integrally molded in the mold, and a method for manufacturing a powder injection molded body. 10. The additional material molding step, wherein a mold part corresponding to a part or all of the sintered material molding mold part is formed in the additional molding part, and the sintered material molding is configured to include the mold part. The method for producing a powder injection-molded article according to claim 9, wherein the sintering material molding step is performed by injecting the sintering material into a mold provided with a mold part. 11. In the sintering material molding step, a mold part corresponding to a part or all of the additional molding mold part is formed in the sintered material compact, and the addition part is configured to include the mold part. The method for producing a powder injection molded article according to claim 9, wherein the additional molding step is performed by injecting the additional molding material into a mold provided with a mold part. 12. The additive molding material contains a powder that does not sinter at the sintering temperature of the sintering material.
A method for manufacturing the powder injection-molded article according to any one of claims 9 to 11. 13. The method for producing a powder injection-molded article according to claim 9, wherein the sinterable powder is a metal powder or a ceramic powder. 14. A sintered material compact formed from a sintered material, which includes sinterable powder and vanida that can be removed in the degreasing step, and the sintered material compact in the degreasing step or the sintering step. A powder injection-molded article, which is integrally molded with an additional molding part formed of an additional molding material that is removed or changes into a separable form. 15. The additional molding part is formed so as to cover a part or all of the surface of the sintered material compact.
The powder injection-molded article according to claim 14. 16. The additive molding material comprises a powder that does not sinter at the sintering temperature of the sintering material.
The powder injection-molded article according to claim 14 or 15. 17. The powder injection-molded article according to claim 14, wherein the sinterable powder is a metal powder or a ceramic powder. 18. A sintered material molding die for molding a sintered material molded body by injecting a sintered material containing sinterable powder and vanida that can be removed in the degreasing step, and the degreasing step or sintering. An additional molding die that molds an additional molding part by injecting an additional molding material that is removed from the sintered material compact in the process or is changed into a separable form, and each of the mold parts is sequentially placed in a mold. Configured to be formed,
Mold for powder injection molding. 19. A powder injection molding die, wherein a part or all of the sintered material molding die portion and / or the additional molding die portion is formed by a LIGA process.