JPH10140210A - Production of sintered compact - Google Patents
Production of sintered compactInfo
- Publication number
- JPH10140210A JPH10140210A JP8298535A JP29853596A JPH10140210A JP H10140210 A JPH10140210 A JP H10140210A JP 8298535 A JP8298535 A JP 8298535A JP 29853596 A JP29853596 A JP 29853596A JP H10140210 A JPH10140210 A JP H10140210A
- Authority
- JP
- Japan
- Prior art keywords
- sintering
- powder
- sintered
- molded body
- powder compression
- 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.)
- Granted
Links
Landscapes
- Powder Metallurgy (AREA)
Abstract
Description
【0001】[0001]
【発明の属する技術分野】本発明は、金属等の材料粉末
を押圧圧縮して成形した柱形状の粉末圧縮成形体を高温
加熱して焼結を行う焼結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 manufacturing a sintered body in which a columnar powder compression molded body formed by pressing and compressing a material powder such as a metal is heated at a high temperature and sintered.
【0002】[0002]
【従来の技術】従来、金属等の材料粉末を単軸成形法で
押圧圧縮し、柱形状の粉末圧縮成形体を成形するための
装置として粉末成形用金型が使用されてきた。この粉末
成形用金型で成形された粉末圧縮成形体は、高温で加熱
焼結されることにより焼結体となる。この焼結は、成形
された粉末圧縮成形体を焼結板の上に載置し、これを電
気炉等の高温炉内に入れて焼結温度まで加熱することに
より行われるが、例えばこの際、焼結板の上に粉末圧縮
成形体を載置し、密閉された高温炉内で一定時間経過さ
せる方法だけでなく、焼結炉中のメッシュベルト上に焼
結板を置き、その上に粉末圧縮成形体を載置してベルト
を駆動させ、焼結炉に連続的に移送させるといったよう
な方法も取ることができる。またメッシュベルトの上に
直接、粉末圧縮成形体を載置させるといったような方法
も取られている。なお焼結板は、焼結時の寸法変化を安
定化させる目的で用いられているものであり、また粉末
圧縮成形体の密度は、焼結後の形状を安定化させる目的
で、一般に均一にしておくことが行われている。2. Description of the Related Art Conventionally, a powder molding die has been used as an apparatus for compressing a material powder such as metal by a uniaxial molding method to form a columnar powder compression molded body. The powder compression molded product formed by the powder molding die is heated and sintered at a high temperature to become a sintered product. This sintering is carried out by placing the compacted powder compact on a sintered plate, placing it in a high-temperature furnace such as an electric furnace and heating it to the sintering temperature. , Place the powder compact on the sintered plate and let it pass for a certain period of time in a closed high-temperature furnace, as well as place the sintered plate on a mesh belt in the sintering furnace, It is also possible to adopt a method in which the powder compact is placed, the belt is driven, and the powder compact is continuously transferred to a sintering furnace. Further, a method of directly placing a powder compact on a mesh belt has been adopted. Sintered plates are used for the purpose of stabilizing dimensional changes during sintering, and the density of powder compacts is generally uniform for the purpose of stabilizing the shape after sintering. Things to do are being done.
【0003】[0003]
【発明が解決しようとする課題】しかしながら実際は、
例え焼結板を用いたとしても、加熱焼結時の粉末圧縮成
形体と焼結板の熱膨張率の違いにより、両者の間に摩擦
抵抗が働き、これが粉末圧縮成形体の熱膨張を局所的に
拘束する働きをするため、結果的に焼結体の直角度精度
を悪化させてしまう。図7は、従来技術による加熱焼結
時の熱膨張モデルを示したものである。27は粉末圧縮
成形体を、29は焼結板を示している。ここで黒矢印
は、その長さにより粉末圧縮成形体27及び焼結板29
の熱膨張率の大きさを示している。粉末圧縮成形体27
の熱膨張率に比べ、焼結板29の熱膨張率は小さい。こ
のため粉末圧縮成形体27と焼結板29の接触面には白
矢印のような摩擦抵抗が働く。この摩擦抵抗により、粉
末圧縮成形体27の接触面側の膨張が拘束され、反対に
非接触面側では自由膨張する。このため図8に示すよう
に、焼結体30には上方に拡がるテーパが形成されてし
まう。このような不具合を解消するための技術が、実開
昭63−2735号公報に開示されている。この技術
は、焼結板上に粉末圧縮成形体と同程度の熱膨張率を有
する板材を載せて複層構造とし、焼結時に粉末圧縮成形
体と板材間に働く摩擦抵抗を低減させ、これにより焼結
体の上端面と下端面の径方向寸法を同一にするというも
のである。またこの他の方法にも、焼結板上にアルミナ
等の粉末を載せ、粉末圧縮成形体と焼結板との間に働く
摩擦抵抗を低減させるというような方法があるが、これ
らの方法は生産性が悪く、しかもコストが高く付いてし
まう。また粉末圧縮成形体と同じ材質の焼結板を使用し
た場合、熱膨張率は同じとなるが、焼結時に両者が張り
付いてしまうため実施は不可能である。本発明は、上述
の問題に鑑みてなされたもので、粉末圧縮成形体の密
度、寸法を変えることで加熱焼結時の粉末圧縮成形体の
載置面に載せる端面と他端面の熱膨張量をコントロール
し、加熱焼結後のテーパ形成を抑制して従来以上の直角
度精度を確保する焼結体の製造方法を提供することを解
決する課題とする。However, in practice,
Even if a sintered plate is used, frictional resistance acts between the powder compression molded body and the sintered plate during thermal sintering due to the difference in the coefficient of thermal expansion, and this causes local thermal expansion of the powder compression molded body. As a result, the squareness accuracy of the sintered body is deteriorated. FIG. 7 shows a thermal expansion model at the time of heat sintering according to the prior art. Reference numeral 27 denotes a powder compression molded body, and 29 denotes a sintered plate. Here, the black arrow indicates the powder compression molded body 27 and the sintered plate 29 depending on the length.
Shows the magnitude of the coefficient of thermal expansion. Powder compression molding 27
The coefficient of thermal expansion of the sintered plate 29 is smaller than the coefficient of thermal expansion. For this reason, a frictional resistance as shown by a white arrow acts on the contact surface between the powder compression molded body 27 and the sintered plate 29. Due to this frictional resistance, expansion of the contact surface side of the powder compression molded body 27 is restricted, and conversely, free expansion occurs on the non-contact surface side. For this reason, as shown in FIG. 8, the sintered body 30 has a taper that expands upward. A technique for solving such a problem is disclosed in Japanese Utility Model Laid-Open No. 63-2735. In this technology, a plate material having the same coefficient of thermal expansion as a powder compression molded body is placed on a sintered plate to form a multi-layer structure, and the frictional resistance between the powder compression molded body and the plate material during sintering is reduced. Thereby, the radial dimension of the upper end face and the lower end face of the sintered body are made the same. In addition, there is a method in which powder such as alumina is placed on a sintered plate to reduce the frictional resistance acting between the powder compact and the sintered plate. The productivity is low and the cost is high. When a sintered plate of the same material as that of the powder compact is used, the coefficient of thermal expansion is the same, but it is impossible to carry out the process because both stick together during sintering. SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has a thermal expansion amount of an end surface and an end surface placed on a mounting surface of a powder compression molded body during heat sintering by changing the density and dimensions of the powder compression molded body. It is an object of the present invention to provide a method for manufacturing a sintered body that controls taper formation after heating and sintering and suppresses the taper formation after heating and sintering, thereby ensuring higher perpendicularity accuracy than before.
【0004】[0004]
【課題を解決するための手段】請求項1に係る焼結体の
製造方法は、加熱焼結前の柱形状の粉末圧縮成形体に予
め密度勾配を付与しておき、加熱焼結時、載置面に粉末
圧縮成形体の高密度側の端面を載せて焼結することを特
徴とする。また、請求項2に係る焼結体の製造方法は、
加熱焼結前の柱形状の粉末圧縮成形体の側面に予めテー
パを形成しておき、加熱焼結時、載置面に粉末圧縮成形
体の面積の大きい側の端面を載せて焼結することを特徴
とする。このため、載置面にて生じる摩擦抵抗の低減を
考慮しなくても従来以上の直角度精度を確保した焼結体
を得ることが可能となる。According to a first aspect of the present invention, there is provided a method for manufacturing a sintered body, wherein a density gradient is given in advance to a columnar powder compression molded body before heat sintering, and a mounting step is performed during heat sintering. The high-density end face of the powder compression molded body is placed on the mounting surface and sintered. The method for manufacturing a sintered body according to claim 2 is as follows.
Before heating and sintering, form a taper on the side surface of the columnar powder compression molded body, and during heating and sintering, place the end face with the larger area of the powder compression molded body on the mounting surface and sinter. It is characterized by. For this reason, it is possible to obtain a sintered body with higher squareness accuracy than before, without considering the reduction of the frictional resistance generated on the mounting surface.
【0005】[0005]
〔第1の実施の形態〕本発明の第1の実施の形態に係る
焼結体の製造方法を、図1〜図5を参照して説明する。
図2の粉末成形用金型10は、ダイベース11に装着さ
れた固定ダイ12と、固定ダイ12の内周面14に沿っ
て下部から挿入された状態で固定されている下型13
と、図示しない駆動源により上下方向に移動可能とされ
た上型18とから構成されている。この図2を基に、前
記粉末成形用金型10を使用して行う粉末圧縮成形体1
7の成形方法を示す。固定ダイ12と下型13とで囲ま
れた円柱形状のキャビティ15に金属等の材料粉末16
を作業者の手あるいはホッパーによって充填する。一般
にこの材料粉末16には、予め金属やセラミックスの粉
末に結合剤、可塑剤等が均一に混合されたものが使用さ
れる。充填された材料粉末16の上面をブレード等で、
固定ダイ12の上面に沿うように整え、次いで下型13
端面と平行な下端面を有する上型18を固定ダイ12の
上部からキャビティ15に挿入し、材料粉末16を4.
5〜5トン/cm2 の力で押圧圧縮する。この押圧圧縮
によって、上型18側の密度が高く、かつ下型13側に
いくほど密度が低い連続した密度勾配を有する粉末圧縮
成形体17が得られる。密度勾配が発生するメカニズム
は次の通りである。粉体は流体とは異なり、型内にて圧
力が加えられた時、圧力伝達は均一、一様にはならな
い。また流体と比較してはるかに大きい摩擦抵抗がある
ため、本実施の形態のように材料粉末16を押圧圧縮し
た際、固定ダイ内周面14と材料粉末16の間に働く摩
擦抵抗によって、材料粉末16は図3のa部から徐々に
固まっていく。これは、上型18の押圧力が下型13に
まで伝達され難く、結果としてa部の固定ダイ内周面1
4に摩擦抵抗が集中してしまうためである。a部が固ま
ると、さらにその箇所に押圧力がかかり、結果として下
型13側の固定ダイ内周面14の摩擦抵抗は小さくな
る。よって、図3のa、b、cと順に密度が低くなるよ
うな連続した密度勾配を有する粉末圧縮成形体17が完
成する。[First Embodiment] A method for manufacturing a sintered body according to a first embodiment of the present invention will be described with reference to FIGS.
The powder molding die 10 shown in FIG. 2 includes a fixed die 12 mounted on a die base 11, and a lower die 13 fixed while being inserted from below along an inner peripheral surface 14 of the fixed die 12.
And an upper die 18 which can be moved vertically by a drive source (not shown). Based on this FIG. 2, the powder compression molded body 1 performed using the powder molding die 10 is described.
7 shows a molding method. A material powder 16 such as a metal is placed in a cylindrical cavity 15 surrounded by a fixed die 12 and a lower mold 13.
Is filled by a worker's hand or a hopper. Generally, as the material powder 16, a material in which a binder, a plasticizer, and the like are uniformly mixed in advance with metal or ceramic powder is used. The upper surface of the filled material powder 16 is bladed or the like,
It is arranged along the upper surface of the fixed die 12 and then the lower die 13
3. An upper die 18 having a lower end surface parallel to the end surface is inserted into the cavity 15 from above the fixed die 12, and the material powder 16 is discharged.
Press and compress with a force of 5 to 5 ton / cm 2 . By this pressing and compression, the powder compression molded body 17 having a high density on the upper mold 18 side and a continuous density gradient with decreasing density toward the lower mold 13 side is obtained. The mechanism by which the density gradient occurs is as follows. Powders, unlike fluids, when pressure is applied in a mold, pressure transmission is not uniform and uniform. Further, since the material powder 16 has much higher frictional resistance as compared with the fluid, when the material powder 16 is pressed and compressed as in the present embodiment, the frictional resistance acting between the inner peripheral surface 14 of the fixed die and the material powder 16 causes The powder 16 gradually solidifies from the part a in FIG. This is because it is difficult for the pressing force of the upper die 18 to be transmitted to the lower die 13, and as a result, the fixed die inner peripheral surface 1
This is because the frictional resistance concentrates on No. 4. When the portion a is hardened, a pressing force is further applied to that portion, and as a result, the frictional resistance of the inner peripheral surface 14 of the fixed die on the lower die 13 side decreases. Accordingly, the compacted powder compact 17 having a continuous density gradient such that the density decreases in the order of a, b, and c in FIG. 3 is completed.
【0006】出来上がった粉末圧縮成形体17は、上型
18、固定ダイ12を上方に取り去った後に取り出され
る。この時、粉末成形用金型10から取り出された粉末
圧縮成形体17には、図1に示すようなテーパが発生し
ている。これは押圧圧縮完了時の型内の粉末圧縮成形体
17において、密度が高い部分のほうが固定ダイ12に
加わる圧力が大きいため型変形量が大きくなるというこ
とや、また粉末圧縮成形体17内部の残留応力も当然密
度の高い部分のほうが大きいため、密度が高い部分のス
プリングバック量のほうが大きくなるということが理由
として挙げられる。なお、成形された粉末圧縮成形体に
含まれる結合剤、可塑剤等は脱脂炉等によって除去され
る。The finished powder compact 17 is taken out after removing the upper die 18 and the fixed die 12 upward. At this time, the powder compression molded body 17 taken out from the powder molding die 10 has a taper as shown in FIG. This is because, in the powder compression molded body 17 in the mold at the time of the completion of the pressing and compression, the higher the pressure applied to the fixed die 12 in the higher density part, the larger the deformation of the mold. The reason for this is that, since the residual stress is naturally larger in the higher density portion, the springback amount in the higher density portion is larger. The binder, plasticizer, and the like contained in the formed powder compression molded body are removed by a degreasing furnace or the like.
【0007】その後、密度勾配を付与した粉末圧縮成形
体17を反転させて高密度側の端面を焼結板19に載置
させ、焼結炉の中で高温焼結させる。なお焼結板19に
は、焼結が普通1000°Cを越える高温で行われるこ
と、また耐熱性に優れたセラミックが非常に高価である
という理由から炭素製の板が用いられている。図1は粉
末圧縮成形体17が焼結体20となる焼成過程を示して
いる。一般に、成形密度が高い方が熱膨張量は大きいた
め、摩擦抵抗が働く載置面に高密度側の端面を載せて、
本来膨張するであろう量よりも少なく膨張させる。一
方、低密度側の端面は拘束させない状態で自由膨張させ
る。事前に、加熱焼結後の焼結体20の上端面と下端面
の径方向寸法がほぼ同一となるように粉末圧縮成形体1
7の密度勾配を調整しておくことで、加熱焼結後のテー
パ形成が抑制される。よって、従来以上の直角度精度を
確保した焼結体20を得ることが可能となる。なお、こ
の粉末圧縮成形体17は密度勾配を有してはいるが、連
続した密度勾配であるため、密度差によって生じる境界
面が存在しない。よって、焼結時に割れが生じることは
ない。[0007] Thereafter, the powder compression molded body 17 having the density gradient is turned over, the end face on the high density side is placed on the sintered plate 19, and is sintered at a high temperature in a sintering furnace. As the sintered plate 19, a carbon plate is used because sintering is usually performed at a high temperature exceeding 1000 ° C. and ceramics having excellent heat resistance are very expensive. FIG. 1 shows a firing process in which the powder compression molded body 17 becomes a sintered body 20. In general, the higher the molding density, the greater the amount of thermal expansion, so put the end face on the high-density side on the mounting surface where frictional resistance works,
Inflate less than the amount that would originally expand. On the other hand, the end face on the low density side is freely expanded without being restrained. In advance, the powder compression molded body 1 is so shaped that the radial dimension of the upper end face and the lower end face of the sintered body 20 after the heat sintering are substantially the same.
By adjusting the density gradient of 7, the taper formation after heat sintering is suppressed. Therefore, it is possible to obtain the sintered body 20 having higher perpendicularity accuracy than the conventional one. Although the powder compression molded body 17 has a density gradient, since the density gradient is continuous, there is no boundary surface caused by the density difference. Therefore, no crack occurs during sintering.
【0008】次に図4、図5を基に、本発明の効果を説
明する。図4は円筒形状の粉末圧縮成形体を成形するキ
ャビティの上視図及び断面図を示している。なお21
は、粉末圧縮成形体に軸方向に中空部を形成するために
キャビティ内に立設させたコアロッドを示している。な
お、このコアロッド21の下端面は、下型の上端面に固
定されている。このキャビティ内で成形された本実施の
形態に係る粉末圧縮成形体Bの成形密度は、上端面付近
で7.0g/cm3 、下端面付近で6.7g/cm3 程
度である。この粉末圧縮成形体Bの高密度の端面を焼結
板上に載置し、炉内温度が1120°Cである焼結炉内
で、窒素もしくは窒素と水素の混合雰囲気の中で、約2
時間加熱焼結する。なお、ここで実際に加熱している時
間はその中の20分程度である。また比較例として、全
体が6.83g/cm3 とほぼ均一密度の粉末圧縮成形
体Aを成形し、Bと同じ条件で加熱焼結した。この焼結
をA、B各々10個ずつ繰り返し、焼結体の円筒度の平
均値を算出した。なお、円筒度とは、加熱焼結後の焼結
体の最大直径から最小直径を引き、それを2で割った値
を示しており、この値が小さいほど直角度精度が高いこ
とを表している。その結果を図5に示す。この図の示す
通り、本実施の形態に係る粉末圧縮成形体Bの加熱焼結
後の円筒度は平均で0.013であり、粉末圧縮成形体
Aの加熱焼結後の円筒度の平均値である0.035に比
べて値が小さくなっている。よって、本実施の形態に係
る粉末圧縮成形体Bの方が直角度精度が高いことが確認
される。また、ばらつき(標準偏差σとして|+3σ|
または|−3σ|)も約0.03から約0.01と、粉
末圧縮成形体Aに対して粉末圧縮成形体Bの方が小さく
なっており、精度が高くなっていることが確認される。
以上により、本発明の効果が確認される。Next, the effects of the present invention will be described with reference to FIGS. FIG. 4 shows a top view and a cross-sectional view of a cavity for forming a cylindrical powder compression molded body. 21
Shows a core rod erected in a cavity to form a hollow portion in the powder compression molded body in the axial direction. The lower end surface of the core rod 21 is fixed to the upper end surface of the lower die. The molding density of the powder compression molded body B according to the present embodiment molded in this cavity is about 7.0 g / cm 3 near the upper end face and about 6.7 g / cm 3 near the lower end face. The high-density end face of the powder compression molded body B is placed on a sintered plate, and is heated for about 2 hours in a sintering furnace having a furnace temperature of 1120 ° C. in nitrogen or a mixed atmosphere of nitrogen and hydrogen.
Heat and sinter for hours. The actual heating time here is about 20 minutes. As a comparative example, a powder compression-molded product A having a substantially uniform density of 6.83 g / cm 3 as a whole was molded and heated and sintered under the same conditions as B. This sintering was repeated 10 times for each of A and B, and the average value of the cylindricity of the sintered body was calculated. In addition, the cylindricity indicates a value obtained by subtracting the minimum diameter from the maximum diameter of the sintered body after the heat sintering and dividing the result by two. The smaller the value is, the higher the squareness accuracy is. I have. The result is shown in FIG. As shown in this figure, the average cylindricity of the powder compression molded body A according to the present embodiment after heat sintering is 0.013, and the average value of the cylindricity of the powder compression molded body A after heat sintering is 0.013. Is smaller than 0.035. Therefore, it is confirmed that the powder compression molded body B according to the present embodiment has higher squareness accuracy. In addition, variation (| + 3σ |
Or | -3σ |) is about 0.03 to about 0.01, which indicates that the powder compression molded body B is smaller than the powder compression molded body A, and that the accuracy is high. .
As described above, the effect of the present invention is confirmed.
【0009】なお、上述した密度勾配を持たせる方法の
他に、例えば上下方向に移動可能な可動ダイを使用し、
押圧圧縮時、上型の下降速度と可動ダイの下降速度を同
一にし、下型側の材料粉末と可動ダイ内周面との摩擦抵
抗を最大にして粉末圧縮成形体の下側の密度を高くする
方法が考えられる。この方法であれば、粉末圧縮成形体
を反転させることなく焼結用治具の上に載置させ、高温
焼結を行うことが可能となる。また、本発明の実施の形
態では、円柱、円筒形状の焼結体の製造方法を示した
が、焼結体の形状はこれに限るものではなく、それ以外
の多角柱形状の焼結体でも製造は可能である。[0009] In addition to the above-described method of providing a density gradient, for example, a movable die that can move in a vertical direction is used,
During pressing and compression, the lowering speed of the upper die and the lowering speed of the movable die are the same, and the frictional resistance between the material powder on the lower die and the inner peripheral surface of the movable die is maximized to increase the density of the lower side of the powder compact. There is a way to do it. According to this method, the powder compression molded body can be placed on a sintering jig without being inverted, and high-temperature sintering can be performed. Further, in the embodiment of the present invention, a method of manufacturing a cylindrical, cylindrical sintered body was described, but the shape of the sintered body is not limited to this, and other polygonal column shaped sintered bodies may be used. Manufacturing is possible.
【0010】〔第2の実施の形態〕本発明の第2の実施
の形態に係る焼結体の製造方法を説明する。本実施の形
態では、内周面にテーパを形成した上下に移動可能な可
動ダイを使用して、押圧圧縮時、上型と可動ダイの相対
速度を調整することによって材料粉末と可動ダイ内周面
との摩擦を低減させ、密度が均一、かつ側面がテーパ形
状である粉末圧縮成形体を成形する。取り出された粉末
圧縮成形体のスプリングバック量は、密度が均一である
ためにどの箇所でも一定であり、よってテーパ角度は可
動ダイ内周面に形成されたテーパの角度と一致する。焼
結は、図6に示されるように、成形された粉末圧縮成形
体57の面積の大きい方の端面を焼結板59に載せて行
われる。つまり、焼結板59に載せる側の端面の面積
を、拘束されない側の端面の面積よりも、摩擦抵抗の働
く分だけ予め大きくしておくことで、加熱焼結後の焼結
体60の上端面と下端面の径方向寸法をほぼ同一とする
ことができる。よって、直角度精度の高い焼結体60を
得ることができる。[Second Embodiment] A method for manufacturing a sintered body according to a second embodiment of the present invention will be described. In the present embodiment, the material powder and the inner periphery of the movable die are adjusted by adjusting the relative speed between the upper die and the movable die during pressing and compression by using a movable die that can move up and down with a tapered inner peripheral surface. A powder compression-molded body having a uniform density and a tapered side surface is formed by reducing friction with the surface. The amount of springback of the powder compression-molded product taken out is constant at any position because the density is uniform, and therefore, the taper angle matches the angle of the taper formed on the inner peripheral surface of the movable die. As shown in FIG. 6, sintering is performed by placing the end face of the molded powder compression molded body 57 having the larger area on the sintered plate 59. That is, by increasing the area of the end face on the side to be placed on the sintered plate 59 by the amount of the frictional resistance in advance from the area of the end face on the unconstrained side, the surface of the sintered body 60 after the heat sintering is formed. The radial dimension of the end face and the lower end face can be substantially the same. Therefore, it is possible to obtain the sintered body 60 having high squareness accuracy.
【0011】なお、本発明の第1、第2の実施の形態で
は、粉末圧縮成形体を焼結板の上に載置して加熱焼結を
行ったが、例えばメッシュベルトの上に直接載置して加
熱焼結を行うことも可能である。また、粉末圧縮成形体
の成形時の押圧圧縮力の範囲は、第1の実施の形態に示
した範囲に限るものではない。また、第2の実施の形態
で示したような内周面にテーパを有するダイを固定して
おいて、第1の実施の形態で示したように成形体に密度
勾配を付与するという方法を取ることも可能である。In the first and second embodiments of the present invention, the powder compact is placed on a sintered plate and subjected to heat sintering. However, for example, the powder compact is placed directly on a mesh belt. It is also possible to perform heat sintering by placing them. Further, the range of the pressing compression force at the time of molding the powder compression molded body is not limited to the range shown in the first embodiment. In addition, a method in which a tapered die is fixed to the inner peripheral surface as shown in the second embodiment, and a density gradient is given to the molded body as shown in the first embodiment. It is also possible to take.
【0012】[0012]
【発明の効果】以上詳述したように、請求項1による本
発明によれば、加熱焼結前の柱形状の成形体に予め密度
勾配を付与しておき、加熱焼結時、載置面に粉末圧縮成
形体の高密度側の端面を載せて焼結を行うことにより、
加熱焼結後の焼結体の直角度精度が向上する。また請求
項2による本発明によれば、加熱焼結前の柱形状の粉末
圧縮成形体の側面に予めテーパを形成しておき、加熱焼
結時、載置面に粉末圧縮成形体の面積の大きい側の端面
を載せて焼結を行うことにより、請求項1と同様に加熱
焼結後の焼結体の直角度精度が向上する。As described above in detail, according to the first aspect of the present invention, a columnar shaped body before heat sintering is provided with a density gradient in advance, and the mounting surface is set at the time of heat sintering. By placing the end face on the high-density side of the powder compression molded body on
The perpendicularity accuracy of the sintered body after the heat sintering is improved. According to the second aspect of the present invention, the side surface of the columnar powder compression molded body before heat sintering is tapered in advance, and the area of the powder compression molded body is set on the mounting surface during heat sintering. By carrying out sintering with the larger end face placed thereon, the squareness accuracy of the sintered body after the heat sintering is improved as in the first aspect.
【図1】本発明の第1の実施の形態の密度勾配を有する
粉末圧縮成形体から焼結体に至るまでの焼結過程を示す
図である。FIG. 1 is a diagram illustrating a sintering process from a powder compact having a density gradient to a sintered compact according to a first embodiment of the present invention.
【図2】本発明の第1の実施の形態の粉末圧縮成形体の
成形工程を示す図である。FIG. 2 is a diagram illustrating a molding step of a powder compression-molded product according to the first embodiment of the present invention.
【図3】本発明の第1の実施の形態の材料粉末から密度
勾配を有する粉末圧縮成形体に至るまでの押圧圧縮過程
を示す図である。FIG. 3 is a diagram showing a pressing and compressing process from the material powder according to the first embodiment of the present invention to a powder compact having a density gradient.
【図4】本発明の第1の実施の形態の粉末圧縮成形体を
成形するキャビティの上視及び断面を示す図である。FIG. 4 is a view showing a top view and a cross section of a cavity for molding the powder compression molded body according to the first embodiment of the present invention.
【図5】本発明の第1の実施の形態の粉末圧縮成形体
A、Bの焼結後の円筒度比較を示す図である。FIG. 5 is a diagram showing a comparison of cylindricity of sintered powder compacts A and B according to the first embodiment of the present invention after sintering.
【図6】本発明の第2の実施の形態の均一な密度の粉末
圧縮成形体から焼結体に至るまでの焼結過程を示す図で
ある。FIG. 6 is a view showing a sintering process from a powder compact having a uniform density to a sintered compact according to the second embodiment of the present invention.
【図7】焼結時に粉末圧縮成形体に働く摩擦抵抗及び熱
膨張率を示す図である。FIG. 7 is a view showing a frictional resistance and a coefficient of thermal expansion acting on a powder compact during sintering.
【図8】均一な密度の粉末圧縮成形体から焼結体へ至る
までの焼結過程を示す従来図である。FIG. 8 is a conventional view showing a sintering process from a powder compact having a uniform density to a sintered compact.
17、57─粉末圧縮成形体 19、59─焼結板 2
0、60─焼結体17,57─Powder compact 19,59─Sintered plate 2
0,60 ° sintered body
Claims (2)
め密度勾配を付与しておき、加熱焼結時、載置面に粉末
圧縮成形体の高密度側の端面を載せて焼結することを特
徴とする焼結体の製造方法。1. A density gradient is previously imparted to a columnar powder compact before heat sintering, and during heating and sintering, the high-density end face of the powder compact is placed on a mounting surface and sintered. A method for producing a sintered body, comprising:
面に予めテーパを形成しておき、加熱焼結時、載置面に
粉末圧縮成形体の面積の大きい側の端面を載せて焼結す
ることを特徴とする焼結体の製造方法。2. A taper is formed on a side surface of a columnar powder compression molded body before heat sintering, and an end face having a large area of the powder compression molded body is placed on a mounting surface during heat sintering. A method for producing a sintered body, characterized by sintering.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP29853596A JP3334518B2 (en) | 1996-11-11 | 1996-11-11 | Manufacturing method of sintered body |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP29853596A JP3334518B2 (en) | 1996-11-11 | 1996-11-11 | Manufacturing method of sintered body |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH10140210A true JPH10140210A (en) | 1998-05-26 |
JP3334518B2 JP3334518B2 (en) | 2002-10-15 |
Family
ID=17860993
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Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP29853596A Expired - Fee Related JP3334518B2 (en) | 1996-11-11 | 1996-11-11 | Manufacturing method of sintered body |
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JP (1) | JP3334518B2 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7384218B2 (en) | 2004-12-16 | 2008-06-10 | Mitsubishi Materials Corporation | Clamping mechanism for cutting insert |
US7479252B2 (en) | 2003-03-28 | 2009-01-20 | Mitsubishi Materials Corporation | Method for manufacturing throwaway tip and apparatus for aligning green compact |
-
1996
- 1996-11-11 JP JP29853596A patent/JP3334518B2/en not_active Expired - Fee Related
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7479252B2 (en) | 2003-03-28 | 2009-01-20 | Mitsubishi Materials Corporation | Method for manufacturing throwaway tip and apparatus for aligning green compact |
US7384218B2 (en) | 2004-12-16 | 2008-06-10 | Mitsubishi Materials Corporation | Clamping mechanism for cutting insert |
US7866924B2 (en) | 2004-12-16 | 2011-01-11 | Mitsubishi Materials Corporation | Clamping mechanism for cutting insert |
Also Published As
Publication number | Publication date |
---|---|
JP3334518B2 (en) | 2002-10-15 |
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