JP2004091823A

JP2004091823A - Method for mass-producing metallic parts by metal powder injection molding technology

Info

Publication number: JP2004091823A
Application number: JP2002252061A
Authority: JP
Inventors: Shigeru Iwata; 岩田　茂
Original assignee: Olympus Corp
Current assignee: Olympus Corp
Priority date: 2002-08-29
Filing date: 2002-08-29
Publication date: 2004-03-25

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for mass-producing metallic parts by a metal powder injection molding technology by which the metallic parts having desired shape can be manufactured by preventing a fault occurring at the time of degreasing and sintering an injection molding body of metal powder. <P>SOLUTION: This method comprises: an injection molding process which forms metal powder injection molding; a tool arranging process which arranges the metal powder injection moldings on a degreasing and sintering tool 3; a degreasing process which heats a metal powder injection moldings and removes a binder and forms a degreased body; a sintering process which heats the degreased body to a sintering temperature in a solid phase and forms the metal parts 2; and a metallic part removing process which removes the metallic parts 2 from the degreasing and sintering tool 3. The degreasing and sintering tool 3 oomprises: a stand member 5 which is composed of a column part 52 and a pedestal part 51 which have a slope 53; and a molding arranging member 4 in which a bottom surface freely attachable/detachable to/from the top end part of the column part 52 has a parallel recessed part 41 and the metal powder injection moldings are arranged. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、金属粉末とバインダとの混合物を金型に射出して形成した金属粉末射出成形体を、脱脂／焼結して金属部品を製造する金属粉末射出成形技術による金属部品量産方法に関する。
【０００２】
【従来の技術】
従来、金属部品は切削、鍛造、プレス、焼結等の加工方法によって形成されていた。そして、近年では、小型或いは複雑な形状であって切削加工、鍛造加工の難しい材料や３次元形状の精密部品の量産に、金属粉末射出成形（以下、ＭＩＭと略記する）技術が利用されている。
【０００３】
このＭＩＭ技術では、金属粉末とこの金属粉末を樹脂部材同様に射出成形可能にするバインダとの混合物を金型に射出して金属粉末射出成形体を形成する射出成形工程と、前記金属粉末射出成形体からバインダを脱脂する脱脂工程と、脱脂後の金属粉末射出成形体を構成する金属粉末を焼結して金属部品を製造する焼結工程とを通して、金属の金属部品を製造する。
【０００４】
【発明が解決しようとする課題】
しかしながら、前述したＭＩＭ技術で、図１１（ａ）に示すように大きな切り欠き部１１１を有する例えば側視型内視鏡の先端硬質部材を形成するための金属粉末射出成形体１１０を射出成形工程において形成することは可能であったが、この金属粉末射出成形体１１０の脱脂、焼結後に、図１１（ｂ）、（ｃ）に示すように潰れた金属粉末射出成形体１１２、１１３になるという不具合が発生して、金属部品を製造することが困難であった。これは、脱脂・焼結によって、金属粉末射出成形体が変形／収縮する特性を有するためであった。
【０００５】
本発明は上記事情に鑑みてなされたものであり、金属粉末射出成形体を脱脂、焼結する際に発生する不具合を防止して、所望の形状の金属部品の製造を安価に、且つより確実に行える金属粉末射出成形技術による金属部品量産方法を提供することを目的にしている。
【０００６】
【課題を解決するための手段】
本発明の金属粉末射出成形技術による金属部品量産方法は、金属粉末とこの金属粉末を樹脂部材同様に射出成形可能にするバインダとの混合物を金型内に射出して金属粉末射出成形体を形成する射出成形工程と、この射出成形工程で形成された金属粉末射出成形体を脱脂・焼結治具に配置する治具配置工程と、この治具配置工程で前記脱脂・焼結治具に配置された金属粉末射出成形体を所定温度まで加熱し、この金属粉末射出成形体に含まれているバインダを除去して脱脂体を形成する脱脂工程と、この脱脂工程で形成された、前記脱脂・焼結治具に配置されている脱脂体を固相焼結する温度に加熱して、金属部品を形成する焼結工程と、この焼結工程で製造された金属部品を前記脱脂・焼結治具から取り外す金属部品取り外し工程とを有している。
【０００７】
そして、前記脱脂・焼結治具は、前記金属粉末射出成形体が有する所定形状を、重力方向に直交する平面に対して所定の角度で傾いた状態で保持する成形体配置部材を具備している。
【０００８】
また、前記第２工程は、金属粉末射出成形体の成形体配置部材に配置される面側にセラミック粉末の層を設けるセラミック粉末層形成工程を有している。
【０００９】
これらの構成によれば、射出成形工程で形成された金属粉末射出成形体を、脱脂、焼結して金属部品を製造する際、金属粉末射出成形体の所定面側にセラミック粉末層を設けて脱脂・焼結治具に配置し、この配置状態で金属粉末射出成形体の脱脂、焼結を行うことにより、金属粉末射出成形体が潰れたりすることなく、脱脂・焼結治具にセラミック粉末層を介して密着した金属部品として安定的に製造される。
【００１０】
【発明の実施の形態】
以下、図面を参照して本発明の実施の形態を説明する。
図１ないし図７は本発明の一実施形態に係り、図１は金属粉末射出成形体を説明する図、図２は金属部品を説明する図、図３は脱脂・焼結治具を説明する図、図４はセラミック粉末層形成工程を説明する図、図５はセラミック粉末層を設けた金属粉末射出成形体を脱脂・焼結治具に配置した状態を説明する図、図６は脱脂工程を経て形成された脱脂体を説明する図、図７は焼結工程を経て形成された金属部品を説明する図である。
【００１１】
なお、図３（ａ）は脱脂・焼結治具を説明する斜視図、図３（ｂ）は成形体配置部材を説明する図、図３（ｃ）は台部材を説明する図、図３（ｄ）は成形体配置部材の凹部を説明する図、図４（ａ）は金属粉末射出成形体の内面にセラミック粉末層を設ける作業例を説明する図、図４（ｂ）はセラミック粉末層を設けた金属粉末射出成形体を示す図である。
【００１２】
本実施形態の金属粉末射出成形技術による金属部品量産方法においては、金属粉末射出成形技術によって形成された図１に示す金属粉末射出成形体１を脱脂、焼結して、図２に示す金属部品２を製造する際、図３（ａ）に示す例えばステンレス部材で形成された脱脂・焼結治具３を使用する。なお、本実施形態においては金属部品２を側視型内視鏡の先端部を構成する先端硬質部材として説明する。
【００１３】
図３（ａ）ないし図３（ｃ）に示すように前記脱脂・焼結治具３は、前記金属粉末射出成形体１が所定状態に配置される略円柱形状に形成した成形体配置部材４と、この成形体配置部材４が着脱自在に配置される台部材５とで構成されている。
【００１４】
図３（ｂ）に示すように前記成形体配置部材４の側面部には、この側面部の表面上を所定の長さ寸法でかつ側面部表面から所定深さ寸法を有する所定形状の凹部４１が形成されている。また、この成形体配置部材４の例えば端部には前記金属粉末射出成形体１の内面先端側に形成されている斜面部１１（図１参照）の形状に対応する傾斜面４２が形成してある。そして、所定の内径寸法を有する略円筒形状の前記金属粉末射出成形体１に、前記成形体配置部材４の一端部を所定位置まで挿入することによって、前記先端硬質部材としての金属部品２を形成するための前記金属粉末射出成形体１を前記成形体配置部材４に配置することが可能になっている。なお、この成形体配置部材４の外径寸法は、前記金属粉末射出成形体１の内面側の径寸法より、変形及び収縮を考慮して所定寸法だけ小径に形成してある。
【００１５】
一方、図３（ｃ）に示すように前記台部材５は、台座部５１と、この台座部５１に対して突設して前記成形体配置部材４の凹部４１が着脱自在に配置される柱部５２とで構成されている。この柱部５２の先端面は、重力方向に直交する平面、即ち、前記台部材５１の底面若しくは台部材５１を載置した平面に対して所定角度θで傾斜した傾斜面５３として形成されている。
【００１６】
図３（ｄ）に示すように前記成形体配置部材４に形成された凹部４１の底面は重力方向に直交する平面に対して平行な平行底面４３として形成されている。したがって、前記成形体配置部材４の凹部４１を前記台部材５の柱部５２の先端部に係入配置することによって、前記凹部４１の平行底面４３が前記柱部５２の傾斜面５３に載置された状態になる。このことによって、前記柱部５２に載置された成形体配置部材４が重力方向に直交する平面、即ち、前記台部材５１の底面若しくは台部材５１を載置した平面に対して所定角度θだけ傾いた状態で配置される。
【００１７】
上述のように構成した脱脂・焼結治具３を使用した金属粉末射出成形技術による金属部品の生産方法を工程毎に説明する。
本実施形態の前記図２に示した金属部品２は、射出成形工程、治具配置工程、脱脂工程、焼結工程、金属部品取り外し工程を経て製造されるものであり、この工程を経て製造された金属部品２はその後、金属部品研磨工程、金属部品矯正工程を経て所定寸法の先端硬質部材として仕上げられる。
【００１８】
前記射出成形工程は、例えばステンレスやチタン等の金属粉末とバインダと呼ばれるポリアセタール等の樹脂部材、流動性を高めるワックス等とを所定の比率で混合した射出成形材料を、所定の金型に注入して金属粉末射出成形体を形成する工程であり、この射出成形工程を経て、前記図１に示した金属粉末射出成形体１が形成される。
【００１９】
前記治具配置工程は、前記射出成形工程で形成された金属粉末射出成形体１を前記脱脂・焼結治具３の成形体配置部材４の所定位置に配置する工程である。この金属粉末射出成形体１を前記成形体配置部材４に配置する際、予め、セラミック粉末層形成工程によって、図４（ｂ）に示すように金属粉末射出成形体１の成形体配置部材側面である内面１２（図４（ａ）参照）にセラミック粉末層６ａを設けておく。
【００２０】
前記セラミック粉末層形成工程では例えば、図４（ａ）に示すように容器７内のセラミック粉末６を金属粉末射出成形体１の内面１２全体に渡ってまぶし、その後、不用なセラミック粉末をふるい落とすことにより、この内面１２に略均一なセラミック粉末層６ａを形成している。
【００２１】
そして、前記内面１２にセラミック粉末層６ａを設けた金属粉末射出成形体１を前記脱脂・焼結治具３の成形体配置部材４の所定位置に配置する。このとき、前記成形体配置部材４が重力方向に直交する平面、即ち、前記台部材５１の底面若しくは台部材５１を載置した平面に対して所定角度θで傾いている。したがって、前記成形体配置部材４に金属粉末射出成形体１を配置することによって、金属粉末射出成形体１の自体の重さにより、図５に示すように金属粉末射出成形体１と成形体配置部材４の有する略円柱状の一端面及び外周面の一部とが前記セラミック粉末層６ａを挟んで密着した状態になる。なお、図中符号１３は金属粉末射出成形体１内に略均一に配置されているバインダを示すものである。
【００２２】
前記脱脂工程は、前記金属粉末射出成形体１が配置されている脱脂・焼結治具３を例えば脱脂用の加熱炉内に配置し、この加熱炉内の温度を常温から徐々に所定温度まで加熱してバインダを除去する工程である。この加熱炉内の温度が徐々に所定温度まで上昇していくことによって、金属粉末射出成形体１内に配置されていたバインダ１３が除去される。このことによって、前記金属粉末射出成形体１は、図６に示すように複数の空隙１４を有するいわゆる軽石状の脱脂体１Ａに変化する。
【００２３】
この脱脂工程のとき、前記金属粉末射出成形体１を脱脂・焼結治具３の成形体配置部材４に配置させたことによって、この金属粉末射出成形体１からバインダ１３が除去されて変形、収縮するとき、金属粉末射出成形体１が成形体配置部材４によって保持されて潰れ等の不具合の発生が防止される。さらに、前記成形体配置部材４の、重力方向に直交する平面、つまり台座部５１の底面若しくは台部材５を載置した平面に対して傾いている所定角度θを、脱脂によって金属粉末射出成形体１が変形、収縮する際における、この金属粉末射出成形体１の自体の重さによる影響を抑制させるように考慮して予め設定しておくことにより、金属粉末射出成形体１の不必要な変形等の不具合の発生も防止される。
【００２４】
前記焼結工程は、前記脱脂体１Ａが配置されている脱脂・焼結治具３を例えば焼結用の真空炉内に配置し直し、この真空炉内の温度を所定温度に加熱してこの脱脂体１Ａを金属部品２に変化させる工程である。この真空炉内を、所定温度に保持することによって炉内に配置されている脱脂体１Ａの金属粉末が固相焼結して軽石状であった脱脂体１Ａが図７に示す高密度の金属部品２になる。
【００２５】
この焼結工程のとき、前記成形体配置部材４に配置された軽石状の脱脂体１Ａの金属粉末が固相焼結し、変形、収縮して金属部品２に変化するが、脱脂体１Ａと成形体配置部材４との間にセラミック粉末層６ａが設けられていることにより、このセラミック粉末層６ａが潤滑剤となって変形、収縮がスムーズに進行する。そして、最終的に、前記成形体配置部材４に対してセラミック粉末層６ａを介して金属部品２が密着状態になる。ここで、前記セラミック粉末層６ａが金属部品２と成形体配置部材４との間に位置することにより、固相焼結して形成される前記金属部品２と前記成形体配置部材４との接合が防止される。さらに、上述のように成形体配置部材４を所定角度θに設定したことによって、前記脱脂工程と同様に、焼結工程による脱脂体１Ａの不必要な変形等の不具合の発生も防止される。
【００２６】
前記金属部品取り外し工程は、前記焼結工程で形成された金属部品２を前記脱脂・焼結治具３の成形体配置部材４から取り外す工程である。前記金属部品２は、セラミック粉末層６ａを介して成形体配置部材４に密着配置されているので、この金属部品２を所定の方向に移動させていくことによって、成形体配置部材４から金属部品２を取り外せる。
【００２７】
前記金属部品研磨工程は、前記金属部品取り外し工程で成形体配置部材４から取り外された金属部品２の表面を、金属特有の光沢を持つ表面にする工程である。前記金属部品２の表面、特にセラミック粉末層６ａに接していた内面１２側は、酸化物が付着して光沢のない曇った面になっている。このため、金属部品２の表面に対して例えばバレル研磨等の研磨加工を施す。このことによって、金属部品２の表面が金属本来の表面状態になる。
【００２８】
前記金属部品矯正工程は、前記金属部品研磨工程で研磨されて金属本来の表面状態を取り戻した金属部品２の寸法を所定寸法に調整する工程である。前記金属部品２を図示しないプレス装置に配置してプレス加工を行うことによって、前記金属部品２が所定寸法の最終製品である先端硬質部材になる。
【００２９】
なお、前記内面１２側と同様、前記セラミック粉末層６ａに接していた成形体配置部材４の外表面もセラミック粉末６が付着したりして、脱脂・焼結治具３として不適切な状態になっている。この場合には、前記成形体配置部材４を台部材５の柱部５２から取り外し、この成形体配置部材４の表面に上述と同様に例えばバレル研磨を施して、元の表面状態にする。このことによって、成形体配置部材４を脱脂・焼結治具３として再使用可能になる。
【００３０】
このように、射出成形工程で形成された金属粉末射出成形体を、脱脂、焼結して金属部品を製造する際、金属粉末射出成形体の所定面にセラミック粉末層を設けた状態にした後、この金属粉末射出成形体を脱脂・焼結治具に配置させることによって、金属粉末射出成形体と脱脂・焼結治具との間にセラミック層を設けた状態で脱脂工程及び焼結工程を行えるので、金属粉末射出成形体や脱脂体が脱脂、焼結時に変形したり収縮して潰れる不具合を確実に防止するとともに、焼結中の金属粉末と脱脂・焼結治具とが接合することを防止して、所望の金属部品をより確実に製造することができる。
【００３１】
また、脱脂・焼結治具を構成する、金属粉末射出成形体が配置される成形体配置部材の外形寸法を、前記金属粉末射出成形体の内面に設けるセラミック粉末層の厚みを考慮して予め小径に形成したことによって、セラミック層を挟んで金属部品が成形体配置部材に密着することで所望の寸法の金属部品を得ることができる。
【００３２】
さらに、脱脂・焼結治具の金属粉末射出成形体が配置される成形体配置部材を台部材の柱部から着脱自在な構成にしたことによって、この成形体配置部材の表面の再研磨を容易に行うことができる。このことによって、この成形体配置部材を脱脂・焼結治具として繰り返し使用することが可能になる。
【００３３】
なお、脱脂・焼結治具は上述した構成に限定されるものではなく、台部材に着脱自在な成形体配置部材に配置される金属粉末射出成形体を、重力方向に直交する平面に対して所定角度θで傾いた状態に保持可能であればよく、以下の図８ないし図１０等に示すような構成であってもよい。
【００３４】
図８は脱脂・焼結治具の他の構成を説明する図であり、図８（ａ）は凹部に特徴のある成形体配置部材を説明する図、図８（ｂ）は成形体配置部材と、成形体配置部材の凹部に対応する柱部を有する台部材とで構成される脱脂・焼結治具を説明する図である。なお、前記実施形態と同様の構成には同符号を付して説明を省略する。
【００３５】
図８（ａ）、（ｂ）に示すように本実施形態の脱脂・焼結治具３Ａにおいては、前記実施形態の柱部５２の先端面に所定角度θの傾斜面５３を形成した台部材５の代わりに、台部材５Ａの柱部５２ａの先端面を、台座部５１ａの底面若しくは台部材５Ａが載置される平面に対して平行な平行面５３ａとして形成する一方、略円柱形状の成形体配置部材４Ａの凹部４１の底面を、側面部に対して所定角度θで傾斜する傾斜底面４３ａにしている。
【００３６】
したがって、前記成形体配置部材４Ａの凹部４１を台部材５Ａの柱部５２ａの先端部に係入配置することによって、柱部５２ａの平行面５３ａに傾斜底面４３ａが載置した状態になって、この成形体配置部材４Ａが重力方向に直交する平面、つまり台座部５１の底面若しくは台部材５Ａを載置した平面に対して所定角度θだけ傾いた状態になる。そして、台部材５Ａに取り付けた成形体配置部材４Ａに金属粉末射出成形体を配置することにより、この金属粉末射出成形体は重力方向に直交する平面に対して、所定角度θで傾いた状態に保持される。
【００３７】
図９は脱脂・焼結治具の別の構成を説明する図であり、図９（ａ）は台座部に特徴のある台部材を説明する図、図８（ｂ）は台部材と成形体配置部材とで構成される脱脂・焼結治具を説明する図である。なお、上述した実施形態と同様の構成には同符号を付して説明を省略する。
【００３８】
図９（ａ）、（ｂ）に示すように本実施形態の脱脂・焼結治具３Ｂは、略円柱形状の前記成形体配置部材４と、台部材５Ｂとで構成されている。この台部材５Ｂの台座部５１ａの底面側には突出長さの異なる足部５５、５６を設けている。それぞれの足部５５、５６の突出長さ寸法は、前記台部材５Ｂを例えば平面プレート上に載置したとき、この台部材５Ｂの平行面５３ａを平面プレートの平面に対して所定角度θで傾くように設定してある。つまり、この台部材５Ｂを平面プレート上に載置することによって、この台部材５Ｂの平行面５３ａは、平行プレートの平面に対して所定角度θで傾いた状態になる。
【００３９】
したがって、前記成形体配置部材４の凹部４１を台部材５Ｂの柱部５２ａの先端部に係入配置することによって、この成形体配置部材４が重力方向に直交する平面、つまり台部材５Ｂを載置した平面プレートの平面に対して所定角度θだけ傾いた状態になる。そして、台部材５Ｂに取り付けた成形体配置部材４に金属粉末射出成形体を配置することにより、この金属粉末射出成形体は重力方向に直交する平面に対して、所定角度θで傾いた状態に保持される。
【００４０】
図１０は脱脂・焼結治具のまた他の構成を説明する図であり、図１０（ａ）は台部材とスペーサーとを説明する図、図８（ｂ）はスペーサーと台部材と成形体配置部材とで構成される脱脂・焼結治具を説明する図である。なお、前述した実施形態と同様の構成には同符号を付して説明を省略する。
【００４１】
図１０（ａ）、（ｂ）に示すように本実施形態の脱脂・焼結治具３Ｂは、略円柱形状の前記成形体配置部材４と、前記台部材５Ａと、スペーサー８とで構成されている。前記スペーサー８には前記台部材５Ａを載置される載置面８１が設けられている。この載置面８１は傾斜面として形成されており、この載置面８１の傾斜角は前記台部材５Ａをこの載置面８１に載置したとき、台部材５Ａの平行面５３ａが、重力方向に直行する平面に対して所定角度θで傾くように設定してある。つまり、前記台部材５Ａをスペーサー８の載置面８１上に載置することによって、この台部材５Ａの平行面５３ａが所定角度θで傾いた状態になる。符号８２は台部材５Ａを保持するための凸部であり、底面凹部にこの凸部８２が当接することによって安定した載置状態になる。
【００４２】
したがって、前記成形体配置部材４の凹部４１を、前記スペーサー８の載置面８１上に載置されている台部材５Ａの先端部に係入配置することによって、この成形体配置部材４が重力方向に直交する平面、つまりスペーサー８の底面若しくはスペーサー８を載置した平面に対して所定角度θだけ傾いた状態になる。そして、スペーサー８の載置面８１上に載置された台部材５Ａに取り付けた成形体配置部材４に金属粉末射出成形体を配置することにより、この金属粉末射出成形体は重力方向に直交する平面に対して、所定角度θで傾いた状態に保持される。
【００４３】
また、前記脱脂・焼結治具の成形体配置部材の形状は上述した形状に限定されるものではない。つまり、金属粉末射出成形体の形状、言い換えれば金属部品の形状によって適宜変更される。
【００４４】
さらに、脱脂・焼結治具の成形体配置部材の重力方向に直交する平面に対する所定角度θも金属粉末射出成形体の形状等を考慮して適宜設定される。
【００４５】
又、脱脂工程と焼結工程とに対応する１つの炉を使用することによって、脱脂体１Ａを別の炉に配置し直すことなく、脱脂工程と焼結工程とを連続的に行える。
【００４６】
尚、本発明は、以上述べた実施形態のみに限定されるものではなく、発明の要旨を逸脱しない範囲で種々変形実施可能である。
【００４７】
［付記］
（１）金属粉末とこの金属粉末を樹脂部材同様に射出成形可能にするバインダとの混合物を金型内に射出して金属粉末射出成形体を形成する射出成形工程と、
この射出成形工程で形成された金属粉末射出成形体を脱脂・焼結治具に配置する治具配置工程と、
この治具配置工程で前記脱脂・焼結治具に配置された金属粉末射出成形体を所定温度まで加熱し、この金属粉末射出成形体に含まれているバインダを除去して脱脂体を形成する脱脂工程と、
この脱脂工程で形成された、前記脱脂・焼結治具に配置されている脱脂体を固相焼結する温度に加熱して、金属部品を形成する焼結工程と、
この焼結工程で製造された金属部品を前記脱脂・焼結治具から取り外す金属部品取り外し工程と、
を有する金属粉末射出成形技術による金属部品量産方法。
【００４８】
（２）前記脱脂・焼結治具は、前記金属粉末射出成形体の有する所定形状を、重力方向に直交する平面に対して所定の角度で傾いた状態で保持する成形体配置部材を具備する付記１に記載の金属粉末射出成形技術による金属部品量産方法。
【００４９】
（３）前記脱脂・焼結治具は、
先端面を重力方向に直交する平面に対して所定の角度に傾斜させて形成した傾斜面を有する柱部及びこの柱部が突設する台座部を有する台部材と、
この台部材の柱部の先端部に着脱自在に係入配置され、底部が重力方向に直交する平面に対して平行な平行底面の凹部を有する所定形状の成形体配置部材と、
を具備する付記２に記載の金属粉末射出成形技術による金属部品量産方法。
【００５０】
このことにより、焼結によって形成された金属部品の取り出し終了後、脱脂・焼結治具を構成する成形体配置部材を取り外して外表面を再研磨することによって、この成形体配置部材の再使用が可能になる。
【００５１】
（４）前記台座部の柱部の先端面を重力方向に直交する平面に対して平行な平行面に形成するとともに、前記成形体配置部材の凹部の底部を重力方向に直交する平面に対して所定の角度に傾斜した傾斜底面に形成した付記３記載の金属粉末射出成形技術による金属部品量産方法。
【００５２】
（５）前記脱脂・焼結治具は、
先端面を重力方向に直交する平面に対して平行に形成した平行面を有する柱部及び一面側に前記柱部が突設して他面側に突出長の異なる２つの足部が突設する台座部を有する台部材と、
この台部材の柱部の先端部に着脱自在に係入配置され、底部が重力方向に直交する平面に対して平行な平行底面の凹部を有する所定形状の成形体配置部材と、を具備する付記２に記載の金属粉末射出成形技術による金属部品量産方法。
【００５３】
（６）前記足部のそれぞれの突出長さ寸法は、前記足部をそれぞれ平面上に載置したとき、前記平行面が重力方向に直交する平面に対して所定の角度で傾くように異なる付記５記載の金属粉末射出成形技術による金属部品量産方法。
【００５４】
（７）前記脱脂・焼結治具は、
先端面を重力方向に直交する平面に対して平行に形成した平行面を有する柱部及びこの柱部が突設する台座部を有する台部材と、
この台部材の柱部の先端部に着脱自在に係入配置され、底部が重力方向に直交する平面に対して平行な平行底面の凹部を有する所定形状の成形体配置部材と、
前記台部材が載置される重力方向に直行する平面に対して所定の角度で傾く載置面及びこの載置面の中途部に位置して突出する凸部とを有するスペーサと、
を具備する付記２に記載の金属粉末射出成形技術による金属部品量産方法。
【００５５】
（８）前記第２工程は、金属粉末射出成形体の成形体配置部材に配置される面側にセラミック粉末の層を設けるセラミック粉末層形成工程を有する請求項１又は請求項２に記載の金属粉末射出成形技術による金属部品量産方法。
【００５６】
【発明の効果】
以上説明したように本発明によれば、金属粉末射出成形体を脱脂、焼結する際に発生する不具合を防止して、所望の形状の金属部品の製造を安価に、且つより確実に行える金属粉末射出成形技術による金属部品量産方法を提供することができる。
【図面の簡単な説明】
【図１】金属粉末射出成形体を説明する図
【図２】金属部品を説明する図
【図３】脱脂・焼結治具を説明する図
【図４】セラミック粉末層形成工程を説明する図
【図５】セラミック粉末層を設けた金属粉末射出成形体を脱脂・焼結治具に配置した状態を説明する図
【図６】脱脂工程を経て形成された脱脂体を説明する図
【図７】焼結工程を経て形成された金属部品を説明する図
【図８】脱脂・焼結治具の他の構成を説明する図
【図９】脱脂・焼結治具の別の構成を説明する図
【図１０】脱脂・焼結治具のまた他の構成を説明する図
【図１１】金属粉末射出成形体と従来の不具合とを説明する図
【符号の説明】
１…金属粉末射出成形体
２…金属部品
３…脱脂・焼結治具
４…成形体配置部材
５…台部材
４１…凹部
５２…柱部
５３…傾斜面[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for mass-producing metal parts by a metal powder injection molding technique for producing a metal part by degrease / sintering a metal powder injection molded body formed by injecting a mixture of a metal powder and a binder into a mold.
[0002]
[Prior art]
Conventionally, metal parts have been formed by processing methods such as cutting, forging, pressing, and sintering. In recent years, metal powder injection molding (hereinafter, abbreviated as MIM) technology has been used for mass production of materials having small or complex shapes, which are difficult to cut and forge, and precision parts having three-dimensional shapes. .
[0003]
In the MIM technique, an injection molding step of injecting a mixture of a metal powder and a binder that enables the metal powder to be injection molded in the same manner as a resin member into a mold to form a metal powder injection molded body; A metal metal part is manufactured through a degreasing step of degreasing a binder from a body and a sintering step of manufacturing a metal part by sintering a metal powder constituting a metal powder injection molded body after degreasing.
[0004]
[Problems to be solved by the invention]
However, using the MIM technique described above, a metal powder injection molded body 110 for forming a distal end hard member of, for example, a side-view type endoscope having a large cutout 111 as shown in FIG. However, after degreasing and sintering the metal powder injection molded body 110, the metal powder injection molded bodies 110 become crushed metal powder injection molded bodies 112 and 113 as shown in FIGS. 11 (b) and 11 (c). And it was difficult to manufacture metal parts. This is because the metal powder injection molded body has a characteristic of being deformed / shrinked by degreasing and sintering.
[0005]
The present invention has been made in view of the above circumstances, and prevents a problem that occurs when degreasing and sintering a metal powder injection molded body, thereby making it possible to manufacture a metal part having a desired shape at low cost and more reliably. It is an object of the present invention to provide a method for mass-producing metal parts by a metal powder injection molding technique which can be performed in a short time.
[0006]
[Means for Solving the Problems]
The method of mass-producing metal parts by the metal powder injection molding technique of the present invention is to form a metal powder injection molded body by injecting a mixture of a metal powder and a binder that enables the metal powder to be injection molded in the same manner as a resin member. An injection molding step, a jig arrangement step of disposing the metal powder injection molded body formed in the injection molding step on a degreasing / sintering jig, and disposing the jig arrangement step on the degreasing / sintering jig. Heating the formed metal powder injection molded body to a predetermined temperature, removing the binder contained in the metal powder injection molded body to form a degreased body, and the degreasing step formed in the degreasing step. A sintering step of heating the degreased body disposed in the sintering jig to a temperature for solid phase sintering to form a metal part; and subjecting the metal part produced in this sintering step to the degreasing / sintering Metal parts to be removed from the tool There.
[0007]
The degreasing / sintering jig includes a molded body disposing member that holds a predetermined shape of the metal powder injection molded body at a predetermined angle with respect to a plane orthogonal to the direction of gravity. I have.
[0008]
Further, the second step includes a ceramic powder layer forming step of providing a ceramic powder layer on a surface of the metal powder injection molded body that is arranged on the molded body arrangement member.
[0009]
According to these configurations, when the metal powder injection molded body formed in the injection molding step is degreased and sintered to produce a metal part, a ceramic powder layer is provided on a predetermined surface side of the metal powder injection molded body. By disposing and sintering the metal powder injection molded body in this arrangement in a degreasing and sintering jig, the ceramic powder can be added to the degreasing and sintering jig without crushing the metal powder injection molded body. It is manufactured stably as a metal part that is in close contact with the layer.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 7 relate to an embodiment of the present invention. FIG. 1 illustrates a metal powder injection molded body, FIG. 2 illustrates a metal part, and FIG. 3 illustrates a degreasing / sintering jig. FIG. 4 is a diagram illustrating a ceramic powder layer forming process, FIG. 5 is a diagram illustrating a state in which a metal powder injection molded body provided with a ceramic powder layer is disposed on a degreasing / sintering jig, and FIG. 6 is a degreasing process. And FIG. 7 is a diagram illustrating a metal part formed through a sintering step.
[0011]
3A is a perspective view illustrating a degreasing and sintering jig, FIG. 3B is a view illustrating a molded body arrangement member, FIG. 3C is a view illustrating a base member, FIG. FIG. 4D is a view for explaining a concave portion of the molded article arranging member, FIG. 4A is a view for explaining an operation example of providing a ceramic powder layer on the inner surface of a metal powder injection molded article, and FIG. It is a figure which shows the metal powder injection molded body provided with.
[0012]
In the method for mass-producing a metal part by the metal powder injection molding technique of the present embodiment, the metal powder injection molded body 1 shown in FIG. 1 formed by the metal powder injection molding technique is degreased and sintered, and the metal part shown in FIG. 2 is manufactured using a degreasing and sintering jig 3 shown in FIG. In the present embodiment, the metal component 2 will be described as a distal end hard member constituting the distal end of the side-view type endoscope.
[0013]
As shown in FIGS. 3 (a) to 3 (c), the degreasing / sintering jig 3 is a molded article arranging member 4 formed in a substantially cylindrical shape on which the metal powder injection molded article 1 is arranged in a predetermined state. And a base member 5 on which the molded body arrangement member 4 is detachably arranged.
[0014]
As shown in FIG. 3B, a concave portion 41 having a predetermined shape having a predetermined length dimension on the surface of the side surface portion and a predetermined depth dimension from the surface of the side surface portion is formed on the side surface portion of the molded body arrangement member 4. Is formed. For example, an inclined surface 42 corresponding to the shape of the slope 11 (see FIG. 1) formed on the front end side of the inner surface of the metal powder injection molded body 1 is formed at, for example, an end of the molded body arrangement member 4. is there. Then, by inserting one end of the molded body arrangement member 4 to a predetermined position into the substantially cylindrical metal powder injection molded body 1 having a predetermined inner diameter, the metal part 2 as the distal end hard member is formed. It is possible to arrange the metal powder injection molded body 1 to be formed on the molded body arrangement member 4. The outer diameter of the molded body arrangement member 4 is smaller than the inner diameter of the metal powder injection molded body 1 by a predetermined size in consideration of deformation and shrinkage.
[0015]
On the other hand, as shown in FIG. 3 (c), the base member 5 has a base 51 and And a part 52. The tip end surface of the column portion 52 is formed as a plane orthogonal to the direction of gravity, that is, an inclined surface 53 inclined at a predetermined angle θ with respect to the bottom surface of the base member 51 or the plane on which the base member 51 is placed. .
[0016]
As shown in FIG. 3D, the bottom surface of the concave portion 41 formed in the molded body arrangement member 4 is formed as a parallel bottom surface 43 parallel to a plane orthogonal to the direction of gravity. Therefore, the parallel bottom 43 of the concave portion 41 is placed on the inclined surface 53 of the column portion 52 by engaging the concave portion 41 of the molded body arrangement member 4 with the tip of the column portion 52 of the base member 5. It will be in the state that was done. As a result, the molded body placing member 4 placed on the column 52 is perpendicular to the direction of gravity, that is, the bottom surface of the base member 51 or the plane on which the base member 51 is mounted by a predetermined angle θ. It is arranged in an inclined state.
[0017]
A method for producing a metal part by a metal powder injection molding technique using the degreasing / sintering jig 3 configured as described above will be described for each process.
The metal part 2 of the present embodiment shown in FIG. 2 is manufactured through an injection molding step, a jig arrangement step, a degreasing step, a sintering step, and a metal part removing step, and is manufactured through this step. Thereafter, the metal component 2 is finished as a tip hard member having a predetermined size through a metal component polishing step and a metal component correction step.
[0018]
In the injection molding step, for example, an injection molding material obtained by mixing a metal powder such as stainless steel or titanium and a resin member such as polyacetal called a binder at a predetermined ratio with a wax or the like for improving fluidity is injected into a predetermined mold. This is a step of forming a metal powder injection molded body, and the metal powder injection molded body 1 shown in FIG. 1 is formed through this injection molding step.
[0019]
The jig disposing step is a step of disposing the metal powder injection molded body 1 formed in the injection molding step at a predetermined position of the molded body disposing member 4 of the degreasing / sintering jig 3. When arranging the metal powder injection molded body 1 on the molded body arranging member 4, the ceramic powder layer forming step is performed in advance on the side of the molded body arranging member of the metal powder injection molded body 1 as shown in FIG. A ceramic powder layer 6a is provided on a certain inner surface 12 (see FIG. 4A).
[0020]
In the ceramic powder layer forming step, for example, as shown in FIG. 4 (a), the ceramic powder 6 in the container 7 is spread over the entire inner surface 12 of the metal powder injection molded body 1, and then unnecessary ceramic powder is sieved. Thus, a substantially uniform ceramic powder layer 6a is formed on the inner surface 12.
[0021]
Then, the metal powder injection molded body 1 provided with the ceramic powder layer 6 a on the inner surface 12 is arranged at a predetermined position of the molded body arrangement member 4 of the degreasing / sintering jig 3. At this time, the molded body arrangement member 4 is inclined at a predetermined angle θ with respect to a plane perpendicular to the direction of gravity, that is, the bottom surface of the base member 51 or the plane on which the base member 51 is placed. Therefore, by arranging the metal powder injection molded body 1 on the molded body arrangement member 4, the metal powder injection molded body 1 and the molded body arrangement as shown in FIG. The substantially cylindrical one end surface and a part of the outer peripheral surface of the member 4 are brought into close contact with the ceramic powder layer 6a therebetween. Reference numeral 13 in the drawing indicates a binder that is disposed substantially uniformly in the metal powder injection molded body 1.
[0022]
In the degreasing step, the degreasing / sintering jig 3 on which the metal powder injection molded body 1 is disposed is disposed in, for example, a heating furnace for degreasing, and the temperature in the heating furnace is gradually decreased from normal temperature to a predetermined temperature. This is a step of removing the binder by heating. By gradually increasing the temperature in the heating furnace to a predetermined temperature, the binder 13 disposed in the metal powder injection molded body 1 is removed. As a result, the metal powder injection molded body 1 changes into a so-called pumice-shaped degreased body 1A having a plurality of voids 14 as shown in FIG.
[0023]
At the time of this degreasing step, the binder 13 is removed from the metal powder injection molded body 1 by disposing the metal powder injection molded body 1 on the molded body arrangement member 4 of the degreasing and sintering jig 3. When shrinking, the metal powder injection molded body 1 is held by the molded body arranging member 4 to prevent the occurrence of problems such as crushing. Further, a predetermined angle θ inclined with respect to a plane perpendicular to the direction of gravity of the molded body arrangement member 4, that is, the bottom surface of the pedestal portion 51 or the plane on which the pedestal member 5 is placed, is removed by degreasing. Unnecessary deformation of the metal powder injection-molded body 1 is set in advance in consideration of suppressing the influence of the weight of the metal powder injection-molded body 1 when the metal powder 1 is deformed and shrunk. And the like are also prevented.
[0024]
In the sintering step, the degreasing / sintering jig 3 on which the degreased body 1A is disposed is re-arranged in, for example, a vacuum furnace for sintering, and the temperature in the vacuum furnace is heated to a predetermined temperature. In this step, the degreased body 1A is changed into the metal part 2. By maintaining the inside of the vacuum furnace at a predetermined temperature, the metal powder of the degreased body 1A disposed in the furnace is solid-phase sintered to form a pumice-shaped degreased body 1A. It becomes part 2.
[0025]
In this sintering step, the metal powder of the pumice-shaped degreased body 1A arranged on the compact-arranged member 4 undergoes solid-phase sintering, deforms and shrinks, and changes into a metal part 2. Since the ceramic powder layer 6a is provided between the molded body arrangement member 4 and the ceramic powder layer 6a, the deformation and shrinkage of the ceramic powder layer 6a smoothly progress as a lubricant. Finally, the metal component 2 is brought into close contact with the molded body arrangement member 4 via the ceramic powder layer 6a. Here, since the ceramic powder layer 6a is located between the metal component 2 and the molded body arrangement member 4, the joining between the metal part 2 formed by solid phase sintering and the molded body arrangement member 4 is performed. Is prevented. Further, by setting the molded body arrangement member 4 at the predetermined angle θ as described above, occurrence of problems such as unnecessary deformation of the degreased body 1A due to the sintering step is prevented as in the above-described degreasing step.
[0026]
The metal part removing step is a step of removing the metal part 2 formed in the sintering step from the molded body arrangement member 4 of the degreasing / sintering jig 3. Since the metal part 2 is disposed in close contact with the molded body arrangement member 4 via the ceramic powder layer 6a, the metal part 2 is moved in a predetermined direction, so that the metal part 2 is moved from the molded body arrangement member 4 to the metal part. 2 can be removed.
[0027]
The metal part polishing step is a step of making the surface of the metal part 2 removed from the molded body placing member 4 in the metal part removal step a surface having a luster specific to metal. The surface of the metal component 2, particularly the inner surface 12 which was in contact with the ceramic powder layer 6 a, is a dull, cloudy surface due to the adhesion of the oxide. For this purpose, the surface of the metal component 2 is subjected to polishing such as barrel polishing. As a result, the surface of the metal component 2 becomes the original surface state of the metal.
[0028]
The metal part correcting step is a step of adjusting the dimensions of the metal part 2 polished in the metal part polishing step to have the original metal surface state restored to a predetermined dimension. By arranging the metal part 2 in a pressing device (not shown) and performing press working, the metal part 2 becomes a tip end hard member which is a final product having a predetermined size.
[0029]
In addition, similarly to the inner surface 12 side, the ceramic powder 6 adheres to the outer surface of the molded body arranging member 4 which has been in contact with the ceramic powder layer 6a, and thus the jig 3 is in an inappropriate state. Has become. In this case, the molded body arrangement member 4 is detached from the column 52 of the base member 5, and the surface of the molded body arrangement member 4 is subjected to, for example, barrel polishing in the same manner as described above to return to the original surface state. This makes it possible to reuse the molded body arrangement member 4 as the degreasing / sintering jig 3.
[0030]
As described above, when the metal powder injection molded body formed in the injection molding process is degreased and sintered to produce a metal part, after the ceramic powder layer is provided on a predetermined surface of the metal powder injection molded body, By arranging the metal powder injection molded body in a degreasing / sintering jig, the degreasing step and the sintering step are performed in a state where a ceramic layer is provided between the metal powder injection molded body and the degreasing / sintering jig. As a result, the metal powder injection molded body and degreased body can be defatted, reliably preventing deformation and shrinkage during sintering and crushing, and joining the sintering metal powder with the degreasing / sintering jig. Is prevented, and a desired metal component can be manufactured more reliably.
[0031]
Further, the outer dimensions of the molded body arranging member constituting the degreasing / sintering jig, on which the metal powder injection molded body is arranged, are determined in advance in consideration of the thickness of the ceramic powder layer provided on the inner surface of the metal powder injection molded body. By forming the metal component with a small diameter, a metal component having a desired size can be obtained by bringing the metal component into close contact with the molded body arrangement member with the ceramic layer interposed therebetween.
[0032]
Further, the molded body disposing member on which the metal powder injection molded body of the degreasing and sintering jig is arranged is detachable from the column of the base member, so that the surface of the molded body disposing member can be easily re-ground. Can be done. This makes it possible to repeatedly use the molded article arrangement member as a degreasing / sintering jig.
[0033]
Note that the degreasing / sintering jig is not limited to the above-described configuration, and the metal powder injection molded body arranged on the molded body arrangement member detachable from the base member can be moved with respect to a plane orthogonal to the direction of gravity. What is necessary is that it can be held in a state of being inclined at a predetermined angle θ, and a configuration as shown in FIGS.
[0034]
8A and 8B are diagrams for explaining another configuration of the degreasing / sintering jig. FIG. 8A is a diagram for explaining a molded body arranging member having a concave portion, and FIG. FIG. 4 is a diagram illustrating a degreasing / sintering jig composed of a base member having a column portion corresponding to a concave portion of a molded body arrangement member. Note that the same components as those of the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted.
[0035]
As shown in FIGS. 8 (a) and 8 (b), in the degreasing / sintering jig 3A of the present embodiment, a base member in which an inclined surface 53 of a predetermined angle θ is formed on the tip end surface of the column part 52 of the above embodiment. Instead of 5, the tip end surface of the column 52a of the base member 5A is formed as a parallel surface 53a parallel to the bottom surface of the base 51a or the plane on which the base member 5A is placed, while forming a substantially cylindrical shape. The bottom surface of the concave portion 41 of the body placement member 4A is an inclined bottom surface 43a that is inclined at a predetermined angle θ with respect to the side surface portion.
[0036]
Therefore, by arranging the concave portion 41 of the molded body arrangement member 4A at the tip of the column portion 52a of the base member 5A, the inclined bottom surface 43a is placed on the parallel surface 53a of the column portion 52a. The molded body arrangement member 4A is inclined by a predetermined angle θ with respect to a plane orthogonal to the direction of gravity, that is, the bottom surface of the base 51 or the plane on which the base member 5A is placed. By arranging the metal powder injection molded body on the molded body arrangement member 4A attached to the base member 5A, the metal powder injection molded body is inclined at a predetermined angle θ with respect to a plane perpendicular to the direction of gravity. Will be retained.
[0037]
9A and 9B are diagrams illustrating another configuration of the degreasing / sintering jig. FIG. 9A is a diagram illustrating a base member having a characteristic pedestal portion, and FIG. 8B is a diagram illustrating the base member and a molded body. It is a figure explaining the degreasing and sintering jig comprised of an arrangement member. The same components as those in the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted.
[0038]
As shown in FIGS. 9A and 9B, the degreasing and sintering jig 3B of the present embodiment is composed of the substantially columnar molded body arrangement member 4 and a base member 5B. On the bottom side of the pedestal portion 51a of the pedestal member 5B, foot portions 55 and 56 having different protruding lengths are provided. The protruding length dimension of each of the feet 55 and 56 is such that when the base member 5B is placed on, for example, a flat plate, the parallel surface 53a of the base member 5B is inclined at a predetermined angle θ with respect to the plane of the flat plate. It is set as follows. That is, by mounting the base member 5B on the flat plate, the parallel surface 53a of the base member 5B is inclined at a predetermined angle θ with respect to the plane of the parallel plate.
[0039]
Therefore, the concave portion 41 of the molded body arrangement member 4 is engaged with the tip of the column portion 52a of the base member 5B, so that the molded body arrangement member 4 places the plane perpendicular to the direction of gravity, that is, the base member 5B. Is inclined by a predetermined angle θ with respect to the plane of the placed flat plate. Then, by arranging the metal powder injection molded body on the molded body arrangement member 4 attached to the base member 5B, the metal powder injection molded body is inclined at a predetermined angle θ with respect to a plane orthogonal to the direction of gravity. Will be retained.
[0040]
FIGS. 10A and 10B are diagrams illustrating another configuration of the degreasing / sintering jig. FIG. 10A is a diagram illustrating a base member and a spacer, and FIG. 8B is a diagram illustrating the spacer, the base member, and a molded body. It is a figure explaining the degreasing and sintering jig comprised of an arrangement member. The same components as those in the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted.
[0041]
As shown in FIGS. 10A and 10B, the degreasing / sintering jig 3B according to the present embodiment includes the substantially cylindrical shaped member arrangement member 4, the base member 5A, and a spacer 8. ing. The spacer 8 is provided with a mounting surface 81 on which the base member 5A is mounted. The mounting surface 81 is formed as an inclined surface, and the inclination angle of the mounting surface 81 is such that when the base member 5A is mounted on the mounting surface 81, the parallel surface 53a of the base member 5A Is set so as to be inclined at a predetermined angle θ with respect to a plane orthogonal to. That is, by mounting the base member 5A on the mounting surface 81 of the spacer 8, the parallel surface 53a of the base member 5A is inclined at the predetermined angle θ. Reference numeral 82 denotes a convex portion for holding the base member 5A, and the convex portion 82 comes into contact with the concave portion on the bottom surface, so that a stable mounting state is achieved.
[0042]
Therefore, the concave portion 41 of the molded body arrangement member 4 is engaged with the tip end of the base member 5A placed on the mounting surface 81 of the spacer 8 so that the molded body arrangement member 4 has a gravity. The plane is inclined by a predetermined angle θ with respect to a plane perpendicular to the direction, that is, the bottom surface of the spacer 8 or the plane on which the spacer 8 is placed. Then, by arranging the metal powder injection molded body on the molded body arrangement member 4 attached to the base member 5A mounted on the mounting surface 81 of the spacer 8, the metal powder injection molded body is orthogonal to the direction of gravity. It is held at a predetermined angle θ with respect to the plane.
[0043]
Further, the shape of the molded body arrangement member of the degreasing / sintering jig is not limited to the above-described shape. That is, the shape is appropriately changed depending on the shape of the metal powder injection molded body, in other words, the shape of the metal part.
[0044]
Further, the predetermined angle θ with respect to the plane orthogonal to the direction of gravity of the molded body arrangement member of the degreasing / sintering jig is also set appropriately in consideration of the shape of the metal powder injection molded body.
[0045]
Further, by using one furnace corresponding to the degreasing step and the sintering step, the degreasing step and the sintering step can be performed continuously without rearranging the degreased body 1A in another furnace.
[0046]
It should be noted that the present invention is not limited to only the above-described embodiments, and various modifications can be made without departing from the spirit of the invention.
[0047]
[Appendix]
(1) an injection molding step of injecting a mixture of a metal powder and a binder capable of injection-molding the metal powder in the same manner as a resin member into a mold to form a metal powder injection molded body;
A jig placement step of placing the metal powder injection molded body formed in this injection molding step on a degreasing / sintering jig;
In this jig arrangement step, the metal powder injection molded body arranged in the degreasing / sintering jig is heated to a predetermined temperature, and the binder contained in the metal powder injection molded body is removed to form a degreased body. A degreasing step,
A sintering step of heating the degreased body formed in the degreasing step, which is arranged in the degreasing / sintering jig, to a temperature for solid-phase sintering to form a metal part,
Removing the metal parts manufactured in this sintering step from the degreasing and sintering jig,
Method for mass-producing metal parts by metal powder injection molding technology having
[0048]
(2) The degreasing / sintering jig includes a molded body arrangement member for holding a predetermined shape of the metal powder injection molded body at a predetermined angle with respect to a plane orthogonal to the direction of gravity. A method for mass-producing metal parts by the metal powder injection molding technique according to supplementary note 1.
[0049]
(3) The degreasing / sintering jig includes:
A column member having an inclined surface formed by inclining a distal end surface at a predetermined angle with respect to a plane orthogonal to the direction of gravity, and a base member having a pedestal portion on which the column portion protrudes,
A molded body arranging member of a predetermined shape, which is removably engaged with the tip of the pillar portion of the base member, and has a recess having a parallel bottom surface whose bottom is parallel to a plane orthogonal to the direction of gravity;
3. A method for mass-producing metal parts by a metal powder injection molding technique according to supplementary note 2, comprising:
[0050]
As a result, after the removal of the metal part formed by sintering, the molded body arrangement member constituting the degreasing / sintering jig is removed and the outer surface is polished again, so that the molded body arrangement member can be reused. Becomes possible.
[0051]
(4) The front end surface of the pillar portion of the pedestal portion is formed as a parallel surface parallel to a plane orthogonal to the direction of gravity, and the bottom of the concave portion of the molded body arrangement member is positioned with respect to a plane orthogonal to the direction of gravity. 3. A method for mass-producing metal parts by a metal powder injection molding technique according to claim 3, wherein the metal parts are formed on an inclined bottom surface inclined at a predetermined angle.
[0052]
(5) The degreasing / sintering jig includes:
A pillar having a parallel surface with its tip surface formed parallel to a plane perpendicular to the direction of gravity, the pillar protruding on one side, and two feet having different protruding lengths protruding on the other side. A base member having a base,
A molded body arrangement member having a predetermined shape, which is removably engaged with a tip end of a pillar portion of the base member, and has a recess having a parallel bottom surface parallel to a plane whose bottom is orthogonal to the direction of gravity. 3. A method for mass-producing metal parts by the metal powder injection molding technique according to 2.
[0053]
(6) The length of each of the projecting lengths of the feet is different from each other such that when the feet are placed on a plane, the parallel plane is inclined at a predetermined angle with respect to a plane orthogonal to the direction of gravity. 5. A method for mass-producing metal parts by the metal powder injection molding technique according to 5.
[0054]
(7) The degreasing / sintering jig includes:
A column member having a parallel surface formed with a distal end surface parallel to a plane orthogonal to the direction of gravity and a pedestal member having a pedestal portion protruding from the column portion,
A molded body arranging member of a predetermined shape, which is removably engaged with the tip of the pillar portion of the base member, and has a recess having a parallel bottom surface whose bottom is parallel to a plane orthogonal to the direction of gravity;
A spacer having a mounting surface inclined at a predetermined angle with respect to a plane perpendicular to the direction of gravity on which the base member is mounted and a convex portion protruding at a position in the middle of the mounting surface,
3. A method for mass-producing metal parts by a metal powder injection molding technique according to supplementary note 2, comprising:
[0055]
(8) The metal according to (1) or (2), wherein the second step includes a ceramic powder layer forming step of providing a layer of ceramic powder on a surface of the metal powder injection-molded body that is arranged on the molded body arrangement member. Mass production method of metal parts by powder injection molding technology.
[0056]
【The invention's effect】
As described above, according to the present invention, it is possible to prevent a problem that occurs when degreasing and sintering a metal powder injection-molded body, and to manufacture a metal part having a desired shape at low cost and more reliably. A method for mass-producing metal parts by a powder injection molding technique can be provided.
[Brief description of the drawings]
FIG. 1 illustrates a metal powder injection molded article. FIG. 2 illustrates a metal part. FIG. 3 illustrates a degreasing / sintering jig. FIG. 4 illustrates a ceramic powder layer forming step. FIG. 5 is a view illustrating a state in which a metal powder injection molded body provided with a ceramic powder layer is arranged in a degreasing / sintering jig; FIG. 6 is a view illustrating a degreased body formed through a degreasing step; FIG. 8 illustrates a metal component formed through a sintering process. FIG. 8 illustrates another configuration of a degreasing / sintering jig. FIG. 9 illustrates another configuration of a degreasing / sintering jig. FIG. 10 is a view for explaining still another configuration of the degreasing / sintering jig. FIG. 11 is a view for explaining a metal powder injection molded body and a conventional defect.
DESCRIPTION OF SYMBOLS 1 ... Metal powder injection molded body 2 ... Metal part 3 ... Degreasing / sintering jig 4 ... Molded body arrangement member 5 ... Base member 41 ... Depression 52 ... Column part 53 ... Inclined surface

Claims

金属粉末とこの金属粉末を樹脂部材同様に射出成形可能にするバインダとの混合物を金型内に射出して金属粉末射出成形体を形成する射出成形工程と、
この射出成形工程で形成された金属粉末射出成形体を脱脂・焼結治具に配置する治具配置工程と、
この治具配置工程で前記脱脂・焼結治具に配置された金属粉末射出成形体を所定温度まで加熱し、この金属粉末射出成形体に含まれているバインダを除去して脱脂体を形成する脱脂工程と、
この脱脂工程で形成された、前記脱脂・焼結治具に配置されている脱脂体を固相焼結する温度に加熱して、金属部品を形成する焼結工程と、
この焼結工程で製造された金属部品を前記脱脂・焼結治具から取り外す金属部品取り外し工程と、
を有することを特徴とする金属粉末射出成形技術による金属部品量産方法。Injection molding step of forming a metal powder injection molded body by injecting a mixture of a metal powder and a binder that enables the metal powder to be injection molded in the same manner as a resin member,
A jig placement step of placing the metal powder injection molded body formed in this injection molding step on a degreasing / sintering jig;
In this jig arrangement step, the metal powder injection molded body arranged in the degreasing / sintering jig is heated to a predetermined temperature, and the binder contained in the metal powder injection molded body is removed to form a degreased body. A degreasing step,
A sintering step of heating the degreased body formed in the degreasing step, which is arranged in the degreasing / sintering jig, to a temperature for solid-phase sintering to form a metal part,
Removing the metal parts manufactured in this sintering step from the degreasing and sintering jig,
A mass production method for metal parts by a metal powder injection molding technique, characterized by having:

前記脱脂・焼結治具は、前記金属粉末射出成形体が有する所定形状を、重力方向に直交する平面に対して所定の角度で傾いた状態で保持する成形体配置部材を具備することを特徴とする請求項１に記載の金属粉末射出成形技術による金属部品量産方法。The degreasing / sintering jig includes a molded body disposing member that holds a predetermined shape of the metal powder injection molded body at a predetermined angle with respect to a plane perpendicular to the direction of gravity. 2. A method for mass-producing metal parts by the metal powder injection molding technique according to claim 1.

前記第２工程は、金属粉末射出成形体の成形体配置部材に配置される面側にセラミック粉末の層を設けるセラミック粉末層形成工程を有することを特徴とする請求項１又は請求項２に記載の金属粉末射出成形技術による金属部品量産方法。The said 2nd process has a ceramic powder layer formation process which provides a layer of ceramic powder on the surface side arrange | positioned at the molded object arrangement | positioning member of a metal powder injection molded body, The Claim 1 or Claim 2 characterized by the above-mentioned. Mass production method of metal parts by metal powder injection molding technology.