JP3129627B2 - Manufacturing method of molded body - Google Patents
Manufacturing method of molded bodyInfo
- Publication number
- JP3129627B2 JP3129627B2 JP07041809A JP4180995A JP3129627B2 JP 3129627 B2 JP3129627 B2 JP 3129627B2 JP 07041809 A JP07041809 A JP 07041809A JP 4180995 A JP4180995 A JP 4180995A JP 3129627 B2 JP3129627 B2 JP 3129627B2
- Authority
- JP
- Japan
- Prior art keywords
- thin film
- preform
- forming
- preformed body
- molded article
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Description
【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION
【０００１】[0001]
【産業上の利用分野】本発明は、成形体の製造方法に関
し、一層詳細には、粉粒体からなる原材料に過剰な液体
を加え、一軸加圧成形により静水圧加圧状態を経て、弾
性変形圧力の範囲内の圧力で成形して予備成形体を得る
成形体の製造方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a molded article, and more particularly, to a method of adding an excessive liquid to a raw material composed of a granular material, and subjecting the raw material to an elastic pressure through a hydrostatic pressure state by uniaxial pressure molding. The present invention relates to a method for manufacturing a molded article obtained by molding at a pressure within a range of deformation pressure to obtain a preformed article.
【０００２】[0002]
【従来の技術】従来、粉粒体状の原材料を加圧成形する
成形体の製造方法においては、粉粒体状の原材料に潤滑
剤、減摩剤、結合剤等の添加物を添加混合して一軸加圧
成形し、予備成形体が成形される。このようにして得ら
れた予備成形体は、前記添加物を除去する脱脂工程を経
て、焼結されて成形体となる。ところが、この脱脂工程
は長時間を要する作業であり、しかも、極めて慎重に行
わなければならない。また、予備成形体の形状が崩れな
いようにするために、添加物が僅かに残るように脱脂が
施されるが、この僅かに残された添加物は、予備成形体
を焼結して成形体を完成させたとき、該成形体の内部に
閉気孔を画成する原因となり、成形体の密度低下、強度
低下の原因となっていた。2. Description of the Related Art Conventionally, in a method of manufacturing a compact by press-molding a granular raw material, additives such as a lubricant, a lubricant, a binder and the like are added to and mixed with the granular raw material. To form a preform. The preformed body obtained in this way is subjected to a degreasing step for removing the additive, and is sintered to form a formed body. However, this degreasing step requires a long time and must be performed very carefully. In addition, in order to prevent the shape of the preformed body from collapsing, degreasing is performed so that a small amount of additive remains, but the slightly remaining additive is formed by sintering the preformed body. When the molded body was completed, it became a cause of defining closed pores inside the molded body, which caused a decrease in the density and strength of the molded body.
【０００３】そこで、このような問題を解決する方法と
して、特開平４−２１１９０４公報には、粉粒体状の原
材料に液体を添加してなる混合物を、一軸加圧成形する
ことにより過剰の液体を除去して予備成形体を成形する
方法が開示されている。この方法によれば、一軸加圧成
形のときに液体を介して圧力が伝達されるために圧力の
伝達効率が良く、そのために粉粒体の再配列が進み、密
度が高くなり、予備成形体の形状が崩れることを防ぐ。
従って、潤滑剤、減摩剤、結合剤等の添加物をほとんど
必要としない。また、添加物を添加して予備成形体を成
形した場合でも、一軸加圧成形のときに液体が流出する
経路が予備成形体の中に形成され、脱脂工程で前記添加
物がその経路を通して排出されるため、脱脂効率が高く
なる。また、大型の成型品を得ることが可能となると記
載されている。In order to solve such a problem, Japanese Patent Application Laid-Open No. 4-212904 discloses a method in which a mixture obtained by adding a liquid to a raw material in the form of a granular material is subjected to uniaxial pressing to form an excess liquid. And a method of forming a preform by removing the same. According to this method, the pressure is transmitted via the liquid during uniaxial pressure molding, so that the pressure transmission efficiency is good, so that the rearrangement of the granular material proceeds, the density is increased, and the preformed body is formed. To prevent the shape from being collapsed.
Thus, little additives such as lubricants, lubricants, binders, etc. are needed. Further, even when the preform is molded by adding an additive, a path through which the liquid flows out during the uniaxial pressure molding is formed in the preform, and the additive is discharged through the path in the degreasing step. As a result, the degreasing efficiency increases. Further, it is described that a large molded product can be obtained.
【０００４】[0004]
【発明が解決しようとする課題】本発明は前記に鑑みな
されたものであって、粉粒体の大きさがその密度に比べ
て大きい粉粒体や、液体との親和性が小さい粉粒体、つ
まり分子間力の働きの小さい粉粒体や、また、粉粒体の
密度が大きく、しかも塑性変形をしない材料や、あるい
はまた、超硬合金やサーメットの如く塑性変形が難し
く、しかも比重の大きい複合粉粒体を原材料として一軸
加圧成形により予備成形体を成形した場合、当該予備成
形体が崩れたり壊れたりすることのない、従って、一軸
加圧成形後の予備成形体の形状保持に優れた成形体の製
造方法を提供することを目的とする。DISCLOSURE OF THE INVENTION The present invention has been made in view of the above, and has been made in view of the above, and has the size of a granular material larger than its density and the granular material having a low affinity for a liquid. In other words, a powder having a small intermolecular force, a material having a high density of the powder and not undergoing plastic deformation, or a plastic such as a cemented carbide or a cermet that is difficult to deform and has a specific gravity When the preformed body is formed by uniaxial pressure molding using the large composite powder as a raw material, the preformed body does not collapse or break, and therefore, is used for maintaining the shape of the preformed body after uniaxial pressing. An object of the present invention is to provide an excellent method for producing a molded article.
【０００５】[0005]
【課題を解決するための手段】前記の目的を達成するた
めに、本発明は、粉粒体状の原材料に過剰量の液体を添
加して混合する第１の工程と、前記第１の工程で得られ
た混合物を一軸加圧成形することにより前記液体の過剰
分を除去しながら予備成形体を得る第２の工程と、前記
第２の工程で得られた前記予備成形体が未乾燥のうちに
該予備成形体の表面に薄膜を形成する第３の工程と、前
記第３の工程で得られた薄膜が形成された予備成形体を
焼結して成形体を得る第４の工程と、を有することを特
徴とする。In order to achieve the above object, the present invention comprises a first step of adding an excessive amount of liquid to a powdery raw material and mixing the raw material; A second step of obtaining a preformed body while removing the excess of the liquid by uniaxially pressing the mixture obtained in the above, and the preformed body obtained in the second step is an undried A third step of forming a thin film on the surface of the preformed body, and a fourth step of sintering the preformed body on which the thin film obtained in the third step is formed to obtain a formed body. , Is characterized by having.
【０００６】[0006]
【作用】本発明に係る成形体の製造方法によれば、予備
成形体の表面に薄膜を形成することにより、予備成形体
の形状を保持することができ、該予備成形体が乾燥して
も崩れたり壊れたりすることを防ぐことができる。According to the method of manufacturing a molded article according to the present invention, the shape of the molded article can be maintained by forming a thin film on the surface of the molded article. It can be prevented from collapsing or breaking.
【０００７】[0007]
【実施例】本発明に係る成形体の製造方法について、好
適な実施例を挙げ、添付の図面を参照しながら以下詳細
に説明する。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for producing a molded article according to the present invention will be described in detail below with reference to preferred embodiments and the accompanying drawings.
【０００８】図１は、本発明に係る成形体の製造方法の
実施例に用いられる一軸加圧成形装置の縦断面図、図２
は、予備成形体に薄膜形成剤を塗布する工程を示す斜視
図、図３は、予備成形体の表面の状態を表す模式図、図
４は、薄膜形成剤の濃度と予備成形体の強度の関係を示
すグラフである。FIG. 1 is a longitudinal sectional view of a uniaxial press forming apparatus used in an embodiment of a method of manufacturing a molded article according to the present invention.
Is a perspective view showing a step of applying a thin film forming agent to the preform, FIG. 3 is a schematic diagram showing a state of the surface of the preform, and FIG. 4 is a graph showing the concentration of the thin film forming agent and the strength of the preform. It is a graph which shows a relationship.
【０００９】本発明に係る成形体の製造方法は、粉粒体
の大きさが粉粒体の密度に比べて大きい粉粒体や、粉粒
体と液体との親和性が小さい場合、つまり分子間力の働
きの小さい場合や、粉粒体の密度が大きく、しかも塑性
変形をしない材料や、あるいは、超硬合金やサーメット
の如く塑性変形が難しく、しかも比重の大きい複合粉粒
体等を原材料１２として、水１４を加えて十分に混合
し、混合物１６を作成する。次に、図１に示すように、
前記混合物１６を一軸加圧成形装置１０のキャビテイ１
８に充填して加圧成形を行い、四角柱状の予備成形体２
０を作成する。このとき、金型２２と下部パンチ２４、
上部パンチ２６との間にわずかな隙間があり、この隙間
から混合物１６に含まれる過剰な水１４が流出し、原材
料１２は水１４を介して均一に加圧される。The method for producing a molded article according to the present invention is applicable to a case where the size of the granular material is larger than the density of the granular material, or when the affinity between the granular material and the liquid is small, Materials with low inter-force, high granular material density and no plastic deformation, or composite granular materials such as cemented carbide and cermet that are difficult to plastically deform and have a large specific gravity As 12, water 14 is added and mixed well to form a mixture 16. Next, as shown in FIG.
Cavity 1 of uniaxial press forming apparatus 10
8 and press-molded to obtain a square pillar-shaped preform 2
Create 0. At this time, the mold 22 and the lower punch 24,
There is a slight gap between the upper punch 26 and the gap, from which excess water 14 contained in the mixture 16 flows out, and the raw material 12 is uniformly pressed through the water 14.
【００１０】加圧成形後、図２に示すように、この予備
成形体２０を一軸加圧成形装置１０から取り出し、直ち
に薄膜を形成する材料（以下、薄膜形成剤という）、展
開剤、湿潤剤が加えられた溶剤を噴霧器２７で前記予備
成形体２０の全面に噴霧して、薄膜２８を形成する（図
３参照）。After the pressure molding, as shown in FIG. 2, the preformed body 20 is taken out of the uniaxial pressure molding apparatus 10 and immediately formed of a material for forming a thin film (hereinafter, referred to as a thin film forming agent), a developing agent, and a wetting agent. Is sprayed over the entire surface of the preform 20 with a sprayer 27 to form a thin film 28 (see FIG. 3).
【００１１】このとき使用される薄膜形成剤は、薄膜２
８の形成が可能であるとともに、溶剤に溶融し、かつ取
り扱いが簡単で、しかも脱脂のときには速やかに分解、
蒸発するものである必要がある。前記の条件を満足する
ものとしては、酢酸ビニル、ニトロセルロース、メラミ
ン樹脂、ポリスチレン樹脂、アクリル樹脂、ポリアミド
樹脂、シアノアクリレートの中のいずれかを選択的に用
いるとよい。この薄膜形成剤は溶剤に溶かして用いられ
る。このときの溶剤としてはアセトン、アルコール、キ
シレン、トルエン、塩化メチレン等があるが、その利便
性を考えると、アルコール、アセトンが適している。前
記薄膜形成剤の含量は、薄膜２８の厚さなどで決められ
るが、前記溶剤に対して１〜３０重量％がよく、好まし
くは、３〜２０重量％程度である。The thin film forming agent used at this time is thin film 2
8 can be formed, melted in a solvent, easy to handle, and quickly decompose when degreasing.
It needs to evaporate. In order to satisfy the above conditions, it is preferable to selectively use any one of vinyl acetate, nitrocellulose, melamine resin, polystyrene resin, acrylic resin, polyamide resin, and cyanoacrylate. This thin film forming agent is used after being dissolved in a solvent. As the solvent at this time, there are acetone, alcohol, xylene, toluene, methylene chloride and the like, but considering its convenience, alcohol and acetone are suitable. The content of the thin film forming agent is determined by the thickness of the thin film 28 and the like, but is preferably 1 to 30% by weight, and more preferably about 3 to 20% by weight based on the solvent.
【００１２】展開剤は予備成形体２０の表面に薄膜２８
がむらなく形成されるようにするために用いられる。前
記展開剤は、安息香酸エチル、安息香酸ブチル、酪酸ブ
チル、エチルセロソルブ、ブチルセロソルブ等があり、
該展開剤は０．５〜１０重量％前記溶剤に加えられる。The developing agent is applied to the surface of the preform 20 by a thin film 28.
It is used to form evenly. The developing agent, ethyl benzoate, butyl benzoate, butyl butyrate, ethyl cellosolve, butyl cellosolve and the like,
The developing agent is added to the solvent in an amount of 0.5 to 10% by weight.
【００１３】潤湿剤は溶剤が急激に乾燥して収縮したり
割れたりしないようにするために用いられる。前記湿潤
剤は、エチルアルコール、プロピルアルコール、イソプ
ロパノール、イソブチノール等があり、該湿潤剤は１〜
４０重量％前記溶剤に加えられる。[0013] Wetting agents are used to prevent the solvent from drying rapidly and shrinking or cracking. Examples of the wetting agent include ethyl alcohol, propyl alcohol, isopropanol, and isobutynol.
40% by weight is added to the solvent.
【００１４】図３に示すように、加圧成形後の予備成形
体２０の内部の空隙には水１４が充満している。薄膜形
成剤がこの予備成形体２０に塗布されるため、該薄膜形
成剤が予備成形体２０の内部に染み込むことは少なく、
予備成形体２０の表面に一様に薄膜２８が形成される。
また、予備成形体２０の表面から内部の水１４の蒸発が
起こるため、形成された薄膜２８には気孔３０が無数に
形成される。この気孔３０の存在は電子顕微鏡で確認す
ることができる。As shown in FIG. 3, the space inside the preform 20 after the pressure molding is filled with water 14. Since the thin film forming agent is applied to the preformed body 20, the thin film forming agent rarely seeps into the preformed body 20,
The thin film 28 is uniformly formed on the surface of the preform 20.
Further, since the water 14 in the inside is evaporated from the surface of the preformed body 20, the pores 30 are formed in the formed thin film 28 innumerably. The presence of the pores 30 can be confirmed with an electron microscope.
【００１５】その後、４８時間、冷却風を供給して強制
的に予備成形体２０を乾燥させ、さらに、７０℃の雰囲
気中に４８時間放置して自然乾燥を行う。このとき、水
１４は前記気孔３０を通して蒸発する。乾燥した予備成
形体２０は表面にできた薄膜２８により、崩れたり壊れ
たりすることがない。また、取り扱いも容易である。After that, the preform 20 is forcibly dried by supplying cooling air for 48 hours, and then left in an atmosphere of 70 ° C. for 48 hours for natural drying. At this time, the water 14 evaporates through the pores 30. The dried preform 20 does not collapse or break due to the thin film 28 formed on the surface. Also, handling is easy.
【００１６】次に、脱脂工程を行う。脱脂の温度および
時間は、室温から１０℃／分の昇温速度で昇温し、３５
０℃、４５０℃、６５０℃でそれぞれ１５分、３０分、
３０分間保持する。Next, a degreasing step is performed. The temperature and time for degreasing were increased from room temperature at a rate of 10 ° C./min.
At 0 ° C, 450 ° C, and 650 ° C for 15 minutes and 30 minutes, respectively.
Hold for 30 minutes.
【００１７】脱脂のとき、予備成形体２０の表面に形成
された薄膜２８には、前記気孔３０が形成されているた
め、該薄膜２８の表面積が広くなり、分解が容易にな
る。At the time of degreasing, the pores 30 are formed in the thin film 28 formed on the surface of the preformed body 20, so that the surface area of the thin film 28 is widened and decomposition is facilitated.
【００１８】そして、これらの予備成形体２０を１０℃
／分で昇温させ、窒素ガス圧５ｂａｒ（５．１ｋｇ／ｃ
ｍ2 ）で１７８０℃の雰囲気中で２時間焼結し、成形体
を完成させる。この完成した成形体は内部に閉気孔が残
らず、密度が高いため、強度が高い。また、従来の製造
方法より大型の成型品を得ることができる。Then, these preforms 20 are heated at 10 ° C.
/ Min and nitrogen gas pressure 5 bar (5.1 kg / c
m 2 ) and sintering in an atmosphere of 1780 ° C. for 2 hours to complete a molded body. This completed molded body has high strength because no closed pores remain therein and the density is high. In addition, it is possible to obtain a molded product larger than a conventional manufacturing method.
【００１９】次に、本発明に係る成形体の製造方法につ
いて、実験例１、実験例２を用いて説明する。実験例２
は薄膜形成剤の濃度と予備成形体の強度に関係する。実験例１ 実験例１に係る成形体の製造方法では、先ず、平均粒径
０．６μｍのイミド分解窒化硅素９０重量％、平均粒径
０．５μｍの酸化イットリウム７重量％、酸化アルミニ
ウム３重量％からなる原材料１２ａを十分に湿式混合し
た。なお、原材料１２ａは、従来の成形体の製造方法で
は成形が難しいと一般的に言われている粉粒体を用い
た。Next, a method for producing a molded article according to the present invention will be described using Experimental Examples 1 and 2. Experimental example 2
Is related to the concentration of the film forming agent and the strength of the preform. EXPERIMENTAL EXAMPLE 1 In the method for producing a molded body according to Experimental Example 1, first, 90% by weight of imido-decomposed silicon nitride having an average particle diameter of 0.6 μm, 7% by weight of yttrium oxide having an average particle diameter of 0.5 μm, and 3% by weight of aluminum oxide The raw material 12a consisting of was sufficiently wet-mixed. In addition, as the raw material 12a, a granular material that is generally said to be difficult to form by a conventional method for manufacturing a formed body was used.
【００２０】前記原材料１２ａを１００重量％に対し水
１４を１７重量％を加え、よく混合し、混合物１６を作
成した。次に、前記混合物１６を一軸加圧成形装置１０
のキャビテイ１８に充填し、１５０ＭＰａ（１５３０ｋ
ｇｆ／ｃｍ2 ）の成形圧で加圧成形し、１２×１２×８
６ｍｍの予備成形体２０ａ〜２０ｇを７個作成した。A mixture 16 was prepared by adding 17% by weight of water 14 to 100% by weight of the raw material 12a and mixing well. Next, the mixture 16 is transferred to the uniaxial pressing apparatus 10.
Into a cavity 18 of 150MPa (1530k
gf / cm 2 ) with a molding pressure of 12 × 12 × 8
Seven 6 mm preformed bodies 20a to 20g were prepared.
【００２１】薄膜形成剤は、酢酸ビニル、ニトロセルロ
ース、メラミン樹脂、ポリスチレン樹脂、アクリル樹
脂、ポリアミド樹脂、シアノアクリレートの７種類につ
いて実験を行った。それぞれの薄膜形成剤を予備成形体
２０ａ〜２０ｇ毎に噴霧器２７で塗布した。溶液の比率
は、薄膜形成剤３重量％、展開剤７重量％（安息香酸ブ
チル３重量％とエチルセロソルブ４重量％）、湿潤剤５
重量％（エチルアルコール３重量％とイソプロパノール
２重量％）を溶剤であるアセトンに溶かした。Experiments were conducted on seven types of thin film forming agents: vinyl acetate, nitrocellulose, melamine resin, polystyrene resin, acrylic resin, polyamide resin, and cyanoacrylate. Each thin film forming agent was applied by a sprayer 27 for each of the preforms 20a to 20g. The ratio of the solution was 3% by weight of a thin film forming agent, 7% by weight of a developing agent (3% by weight of butyl benzoate and 4% by weight of ethyl cellosolve), and 5% by weight of a wetting agent.
% By weight (3% by weight of ethyl alcohol and 2% by weight of isopropanol) were dissolved in acetone as a solvent.
【００２２】前記予備成形体２０ａ〜２０ｇに溶剤を塗
布してから４８時間、冷却風を供給し、乾燥して３点曲
げ強度を測定した（風乾強度）。さらに、７０℃の雰囲
気中に４８時間放置し、その後の３点曲げ強度を測定し
た（乾燥強度）。Forty-eight hours after applying the solvent to the preforms 20a to 20g, cooling air was supplied and dried, and the three-point bending strength was measured (air-dry strength). Furthermore, it was left in an atmosphere of 70 ° C. for 48 hours, and then the three-point bending strength was measured (dry strength).
【００２３】このとき、前記予備成形体２０ａ〜２０ｇ
は崩れたり壊れたりすることがなく、取り扱いが容易で
あり、搬送にも何ら支障が生ずることがなかった。At this time, the preforms 20a to 20g
There was no breakage or breakage, handling was easy, and there was no trouble in transport.
【００２４】測定の後、前記予備成形体２０ａ〜２０ｇ
に対して脱脂工程を施した。脱脂の温度および時間は、
室温雰囲気から１０℃／分の昇温速度で昇温し、３５０
℃、４５０℃、６５０℃でそれぞれ１５分、３０分、３
０分間保持した。After the measurement, the preforms 20a to 20g
Was subjected to a degreasing step. Degreasing temperature and time
The temperature is raised from the room temperature atmosphere at a rate of 10 ° C./min.
℃, 450 ℃, 650 ℃ for 15 minutes, 30 minutes, 3
Hold for 0 minutes.
【００２５】その後、これらの予備成形体２０ａ〜２０
ｇを１０℃／分で昇温し、窒素ガス圧５ｂａｒ（５．１
ｋｇｆ／ｃｍ2 ）で１７８０℃の雰囲気中で２時間焼結
し、成形後の３点曲げ強度を測定した（焼結後強度）。
これらの測定データを表１に示す。Thereafter, these preforms 20a-20
g at a rate of 10 ° C./min and a nitrogen gas pressure of 5 bar (5.1
(kgf / cm 2 ) for 2 hours in an atmosphere of 1780 ° C., and the three-point bending strength after molding was measured (strength after sintering).
Table 1 shows these measurement data.
【００２６】さらに、比較のために、原材料１２を１０
０重量％に対し、パラフィンロウとパラフィンワックス
を合計３５重量％加えて混合し、加圧成形して予備成形
体２０ｈを作成した。該予備成形体２０ｈを１１０℃の
雰囲気中に２４時間放置して乾燥させた後、前記予備成
形体２０ｈの３点曲げ強度を測定した（表１の乾燥強度
参照）。Further, for comparison, the raw material 12 was
A total of 35% by weight of paraffin wax and paraffin wax was added to 0% by weight and mixed, followed by pressure molding to prepare a preform 20h. The preform 20h was left to dry in an atmosphere at 110 ° C. for 24 hours and dried, and then the three-point bending strength of the preform 20h was measured (see the dry strength in Table 1).
【００２７】この予備成形体２０ｈを、大気中で２００
℃までは５℃／分、２５０℃までは２℃／分、それ以上
は２℃／時で温度を上げ、最終的に５００℃まで温度を
上げて脱脂を施した。保持温度は、１５０℃、２００
℃、２５０℃、３００℃、３５０℃、４５０℃、５００
℃で、それぞれ２時間、２時間、２時間、２時間、３時
間、４時間、１０時間とした。The preformed body 20h is placed in the atmosphere for 200 hours.
The temperature was raised at 5 ° C./min to 250 ° C., 2 ° C./min up to 250 ° C., and 2 ° C./hour above 250 ° C., and finally the temperature was raised to 500 ° C. to perform degreasing. The holding temperature is 150 ° C, 200
℃, 250 ℃, 300 ℃, 350 ℃, 450 ℃, 500
C. for 2 hours, 2 hours, 2 hours, 2 hours, 3 hours, 4 hours, and 10 hours, respectively.
【００２８】そして、この予備成形体２０ｈを１０℃／
分で昇温し、窒素ガス圧５ｂａｒ（５．１ｋｇｆ／ｃｍ
2 ）で１７８０℃の雰囲気中で２時間焼結し、成形後の
３点曲げ強度を測定した（焼結後強度）。この測定デー
タを表１に示す。Then, the preform 20h is heated at 10 ° C. /
And the nitrogen gas pressure is 5 bar (5.1 kgf / cm
In 2 ), sintering was performed for 2 hours in an atmosphere of 1780 ° C., and the three-point bending strength after molding was measured (strength after sintering). Table 1 shows the measurement data.
【００２９】この測定データから、本発明に係る方法で
成形された予備成形体２０ａ〜２０ｇは、従来技術に係
る方法で成形された予備成形体２０ｈより、乾燥後、焼
結後とも、強度が増した。From the measurement data, it is found that the preforms 20a to 20g formed by the method according to the present invention have a higher strength after drying and sintering than the preform 20h formed by the method according to the prior art. Increased.
【００３０】さらに、従来技術に係る方法で得られる予
備成形体２０ｈの肉厚は、最大でも１０ｍｍ程度であっ
たが、実験例１に係る方法で成形された予備成形体２０
ａ〜２０ｇでは、１００ｍｍ程度の肉厚まで成形可能で
あった。Further, the thickness of the preformed body 20h obtained by the method according to the prior art was at most about 10 mm.
With a to 20 g, it was possible to mold to a thickness of about 100 mm.
【００３１】[0031]
【表１】 [Table 1]
【００３２】実験例２ 実験例２に係る成形体の製造方法では、先ず、ＪＩＳ規
格のＷＣ２５の粉末８７重量％、コバルト（Ｃｏ）の粉
末１０重量％、炭化ニオブ（ＮｂＣ）の粉末３重量％か
らなる原材料１２ｂを十分に混合した。なお、原材料１
２ｂは、従来の成形体の製造方法では成形が難しいと言
われている粉粒体を用いた。 EXPERIMENTAL EXAMPLE 2 In the method of manufacturing a molded body according to Experimental Example 2, first, 87% by weight of JIS WC25 powder, 10% by weight of cobalt (Co) powder, 3% by weight of niobium carbide (NbC) powder. Was thoroughly mixed. Raw material 1
For 2b, a granular material which is said to be difficult to mold by a conventional method for producing a molded body was used.
【００３３】次に、この原材料１２ｂに水１４を加えて
よく混合し、混合物１６を作成した。この混合物１６を
一軸加圧成形装置１０のキャビテイ１８に充填し、成形
圧１０００ｋｇｆ／ｃｍ2 で加圧して予備成形体２０ｉ
を作成した。前記予備成形体２０ｉの大きさは、長さ８
０ｍｍ、幅１２．５ｍｍ、厚さ８〜１０ｍｍとした。Next, water 14 was added to the raw material 12b and mixed well to prepare a mixture 16. The mixture 16 is filled into the cavity 18 of the uniaxial pressing apparatus 10 and pressurized at a forming pressure of 1000 kgf / cm 2 to form a preformed body 20i.
It was created. The size of the preform 20i is a length 8
0 mm, width 12.5 mm, thickness 8 to 10 mm.
【００３４】予備成形後、直ちに塗布液を前記予備成形
体２０ｉの全面に塗布した。このときの塗布液は、溶剤
であるアセトンに薄膜形成剤であるニトロセルロースを
滴下して作成した。この場合、ニトロセルロースの濃度
０〜３０重量％までの溶剤を用意し、それぞれの濃度に
おいて前記予備成形体２０ｉに塗布した。Immediately after the preforming, a coating solution was applied to the entire surface of the preformed body 20i. The coating liquid at this time was prepared by dropping nitrocellulose as a thin film forming agent into acetone as a solvent. In this case, a solvent having a nitrocellulose concentration of 0 to 30% by weight was prepared and applied to the preform 20i at each concentration.
【００３５】次に、前記の塗布液を塗布した予備成形体
２０ｉを６０℃で４８時間乾燥した。この乾燥後の予備
成形体２０ｉを４０ｍｍの長さに切って３点曲げ強度を
測定した。この結果を図４の実線３２で示す。Next, the preform 20i coated with the coating solution was dried at 60 ° C. for 48 hours. The dried preformed body 20i was cut into a length of 40 mm, and the three-point bending strength was measured. This result is shown by the solid line 32 in FIG.
【００３６】搬送のときに予備成形体２０ｉが崩れたり
壊れたりしないようにするためには、０．７ＭＰａ
（７．１４ｋｇｆ／ｃｍ2 ）以上の強度が必要であった
（図４の実線３４参照）。図４のグラフからわかるよう
に、ニトロセルロースの濃度が約２％以上あれば十分な
強度が得られたが、ニトロセルロースが２５％を超える
と、予備成形体２０ｉが乾燥したときに割れが生じた
（図４の斜線部３６参照）。In order to prevent the preform 20i from collapsing or breaking during transportation, the preform 20i must have a pressure of 0.7 MPa.
(7.14 kgf / cm 2 ) or more was required (see the solid line 34 in FIG. 4). As can be seen from the graph of FIG. 4, sufficient strength was obtained when the concentration of nitrocellulose was about 2% or more, but when the concentration of nitrocellulose exceeded 25%, cracks occurred when the preform 20i was dried. (See the hatched portion 36 in FIG. 4).
【００３７】従って、実験例２では、予備成形後、薄膜
形成剤を適当な濃度に溶かした塗布液を予備成形体２０
ｉに塗布することにより、乾燥後の該予備成形体２０ｉ
の強度が増して、割れが生じることなく、取り扱いや搬
送が容易になることが分かった。Therefore, in Experimental Example 2, after the preforming, the coating liquid in which the thin film forming agent was dissolved at an appropriate concentration was applied to the preformed body 20.
i, the dried preformed body 20i
It was found that the handling and transportation were facilitated without increasing the strength and causing cracks.
【００３８】[0038]
【発明の効果】本発明に係る成形体の製造方法によれ
ば、以下のような効果ならびに利点が得られる。According to the method for producing a molded article according to the present invention, the following effects and advantages can be obtained.
【００３９】粉粒体の大きさがその密度に比べて大きい
ものや、粉粒体と液体との親和性が小さい場合、つまり
分子間力の働きの小さい場合や、また、粉粒体の密度が
大きく塑性変形をしない材料や、あるいはまた、超硬合
金やサーメットの如く塑性変形が難しく、しかも比重の
大きい複合粉粒体を原料として一軸加圧成形を行って予
備成形体を作成しても、薄膜を形成する材料を用いるた
めに、該予備成形体は形状保持特性に優れ、乾燥しても
崩れたり、壊れたりすることを防ぐことができる。従っ
て、予備成形体としての取り扱いも容易となる効果が得
られる。When the size of the granular material is larger than its density, when the affinity between the granular material and the liquid is low, that is, when the function of the intermolecular force is small, or when the density of the granular material is small. However, even if a material that does not undergo plastic deformation or plastic deformation is difficult such as a cemented carbide or cermet, and a composite powder having a large specific gravity is used as a raw material, uniaxial pressure molding is performed to produce a preformed body Since a material for forming a thin film is used, the preform has excellent shape retention characteristics and can be prevented from being broken or broken even when dried. Therefore, an effect that the handling as the preformed body becomes easy is obtained.
【図１】本発明に係る成形体の製造方法の実施例に用い
られる成形装置の縦断面図である。FIG. 1 is a longitudinal sectional view of a molding apparatus used in an embodiment of a method for producing a molded article according to the present invention.
【図２】予備成形体の表面に薄膜形成剤を塗布する工程
を示す斜視図である。FIG. 2 is a perspective view showing a step of applying a thin film forming agent to the surface of a preform.
【図３】予備成形体の表面の状態を表す模式図である。FIG. 3 is a schematic view illustrating a state of a surface of a preform.
【図４】薄膜形成剤の濃度と予備成形体の強度の関係を
示すグラフである。FIG. 4 is a graph showing the relationship between the concentration of a thin film forming agent and the strength of a preform.
１０…一軸加圧成形装置 １２、１２ａ、１２
ｂ…原材料 １４…水 １６…混合物 １８…キャビテイ ２０、２０ａ〜２０
ｉ…予備成形体 ２７…噴霧器 ２８…薄膜 ３０…気孔10. Uniaxial pressure molding device 12, 12a, 12
b ... raw material 14 ... water 16 ... mixture 18 ... cavity 20, 20a-20
i: Preformed body 27: Sprayer 28: Thin film 30: Pores
───────────────────────────────────────────────────── フロントページの続き (72)発明者 桑原 光雄 埼玉県狭山市新狭山１−10−１ ホンダ エンジニアリング株式会社内 (58)調査した分野(Int.Cl.7，ＤＢ名) B22F 3/24 102 ──────────────────────────────────────────────────続 き Continued on the front page (72) Mitsuo Kuwahara 1-10-1 Shinsayama, Sayama-shi, Saitama Honda Engineering Co., Ltd. (58) Field surveyed (Int. Cl. 7 , DB name) B22F 3/24 102
Claims (4)
て混合する第１の工程と、 前記第１の工程で得られた混合物を一軸加圧成形するこ
とにより前記液体の過剰分を除去しながら予備成形体を
得る第２の工程と、 前記第２の工程で得られた前記予備成形体が未乾燥のう
ちに該予備成形体の表面に薄膜を形成する第３の工程
と、 前記第３の工程で得られた薄膜が形成された予備成形体
を焼結して成形体を得る第４の工程と、 を有することを特徴とする成形体の製造方法。1. A first step of adding and mixing an excessive amount of liquid to a raw material in the form of powder and granules, and forming the mixture obtained in the first step by uniaxial pressure molding, whereby the excess amount of the liquid is obtained. A second step of obtaining a preform while removing the component; and a third step of forming a thin film on the surface of the preform while the preform obtained in the second step is not dried. And a fourth step of sintering the preformed body on which the thin film obtained in the third step is formed to obtain a formed body.
て、 薄膜を形成する前記第３の工程は、薄膜を形成する材料
を前記予備成形体に塗布する工程であることを特徴とす
る成形体の製造方法。2. A method according to claim 1, wherein said third step of forming a thin film is a step of applying a material for forming a thin film to said preformed body. How to make the body.
において、 薄膜を形成する前記第３の工程は、薄膜を形成する材料
を前記予備成形体に噴霧する工程であることを特徴とす
る成形体の製造方法。3. The method for manufacturing a molded article according to claim 1, wherein said third step of forming a thin film is a step of spraying a material for forming a thin film onto said preformed body. Method for producing a molded article.
の製造方法において、 前記第３の工程で使用される薄膜を形成する材料は、酢
酸ビニル、ニトロセルロース、メラミン樹脂、ポリスチ
レン樹脂、アクリル樹脂、ポリアミド樹脂、シアノアク
リレートの中の少なくとも１つであることを特徴とする
成形体の製造方法。4. The method for producing a molded article according to claim 1, wherein the material for forming the thin film used in the third step is vinyl acetate, nitrocellulose, a melamine resin, or a polystyrene resin. , An acrylic resin, a polyamide resin, and a cyanoacrylate.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP07041809A JP3129627B2 (en) | 1995-03-01 | 1995-03-01 | Manufacturing method of molded body |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP07041809A JP3129627B2 (en) | 1995-03-01 | 1995-03-01 | Manufacturing method of molded body |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08239702A JPH08239702A (en) | 1996-09-17 |
| JP3129627B2 true JP3129627B2 (en) | 2001-01-31 |
Family
ID=12618651
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP07041809A Expired - Fee Related JP3129627B2 (en) | 1995-03-01 | 1995-03-01 | Manufacturing method of molded body |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3129627B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5519299B2 (en) * | 2010-01-08 | 2014-06-11 | 奇▲こう▼科技股▲ふん▼有限公司 | Heat sink manufacturing method |
-
1995
- 1995-03-01 JP JP07041809A patent/JP3129627B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH08239702A (en) | 1996-09-17 |
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