JPH0140725B2 - - Google Patents
Info
- Publication number
- JPH0140725B2 JPH0140725B2 JP58020372A JP2037283A JPH0140725B2 JP H0140725 B2 JPH0140725 B2 JP H0140725B2 JP 58020372 A JP58020372 A JP 58020372A JP 2037283 A JP2037283 A JP 2037283A JP H0140725 B2 JPH0140725 B2 JP H0140725B2
- Authority
- JP
- Japan
- Prior art keywords
- core
- injection molding
- ferrite
- less
- cylindrical
- 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
Links
- 238000001746 injection moulding Methods 0.000 claims description 30
- 229910000859 α-Fe Inorganic materials 0.000 claims description 24
- 238000000354 decomposition reaction Methods 0.000 claims description 15
- 238000004519 manufacturing process Methods 0.000 claims description 14
- 230000002093 peripheral effect Effects 0.000 claims description 11
- -1 polypropylene Polymers 0.000 claims description 11
- 239000011230 binding agent Substances 0.000 claims description 10
- 239000004793 Polystyrene Substances 0.000 claims description 9
- 229920002223 polystyrene Polymers 0.000 claims description 9
- 239000004743 Polypropylene Substances 0.000 claims description 8
- 229920001155 polypropylene Polymers 0.000 claims description 8
- 235000021355 Stearic acid Nutrition 0.000 claims description 7
- 238000010438 heat treatment Methods 0.000 claims description 7
- QIQXTHQIDYTFRH-UHFFFAOYSA-N octadecanoic acid Chemical compound CCCCCCCCCCCCCCCCCC(O)=O QIQXTHQIDYTFRH-UHFFFAOYSA-N 0.000 claims description 7
- OQCDKBAXFALNLD-UHFFFAOYSA-N octadecanoic acid Natural products CCCCCCCC(C)CCCCCCCCC(O)=O OQCDKBAXFALNLD-UHFFFAOYSA-N 0.000 claims description 7
- 238000005245 sintering Methods 0.000 claims description 7
- 239000008117 stearic acid Substances 0.000 claims description 7
- 239000012768 molten material Substances 0.000 claims description 6
- 229910001035 Soft ferrite Inorganic materials 0.000 claims description 5
- 238000002347 injection Methods 0.000 claims description 5
- 239000007924 injection Substances 0.000 claims description 5
- 239000002994 raw material Substances 0.000 claims description 4
- 238000002485 combustion reaction Methods 0.000 claims 2
- 239000011162 core material Substances 0.000 description 43
- 239000011368 organic material Substances 0.000 description 15
- 238000000034 method Methods 0.000 description 8
- 238000000465 moulding Methods 0.000 description 8
- 239000008188 pellet Substances 0.000 description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 4
- 229910052799 carbon Inorganic materials 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 239000012778 molding material Substances 0.000 description 4
- 238000002844 melting Methods 0.000 description 3
- 230000008018 melting Effects 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- 239000004698 Polyethylene Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 229920000573 polyethylene Polymers 0.000 description 2
- 229910018605 Ni—Zn Inorganic materials 0.000 description 1
- 238000000748 compression moulding Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000003203 everyday effect Effects 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 238000004898 kneading Methods 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 238000011179 visual inspection Methods 0.000 description 1
Landscapes
- Producing Shaped Articles From Materials (AREA)
- Moulds, Cores, Or Mandrels (AREA)
Description
利用産業分野
この発明は、ロータリートランスコア用円筒状
フエライト材料の如く内周面に複雑な形状を有す
る筒状フエライトの射出成形による製造方法と中
子に係り、成形時に従来の内金型にかえて使用す
る中子を特定組成となして成型体の脱バインダー
ー処理ときに分解消滅させて製造を容易にした筒
状フエライトの製造方法及び射出成形用中子に関
する。
従来の技術
従来、ロータリートランスコア用円筒状フエラ
イト等の内周面に複雑な凹凸を有する製品は、円
筒状フエライト素材を製造したのち、機械加工に
より内周面の複雑形状を形成していたため、多大
の工程を有し、良好な品質の製品を得ることが困
難であつた。
そこで、機械加工にかえて複雑な形状を形成で
きる射出成形方法が採用されるようになつた。
一般に、フエライトの射出成形方法は、フエラ
イト粉末と有機材料を所要の混合比で加熱混練
し、押出し成形機でペレツト化し、このペレツト
成形材料を射出成形機内で加熱溶融し、所要形状
を有し焼結時の収縮率を考慮した寸法の外金型と
内金型とで形成される射出空間に、上記の溶融材
料を加圧射出し、射出成形を完了する方法であ
る。
したがつて、成形体に加圧される圧力が３次元
的圧力となり、一軸性圧縮成形法のプレス成形に
比較して複雑な形状の成形に適している。
従来技術の問題点
しかしながら、上述したロータリートランスコ
ア等の如き内周面に溝部を有する複雑形状のもの
を射出成型すると、金型構造が大変複雑となり、
金型コストが高くなり、さらに成形体の寸法精度
及び量産性に種々の問題があつた。
この発明は、かかる内周面形状の複雑な円筒、
角筒等の筒状フエライトの製造に際し、容易に成
形でき、金型構造が簡単で安価に製造可能で、良
好な外観かつ高い寸法精度が得られ、量産化に極
めて有効な射出成形による筒状フエライトの製造
方法を目的としている。
発明の概要
この発明は、
射出成形用フエライト原料を溶融し、
外金型と熱膨脹係数が６×10-5／℃未満で150
℃〜350℃の分解温度を有し、かつアタクチツク
ポリプロピレン（APP）30wt％〜65wt％、ポリ
スチレン35wt％〜70wt％、あるいは更にステリ
アン酸35wt％以下からなり、筒状フエライト焼
結体の内周凹形状に対応する外周凸形状を有する
中子とによつて形成される射出成形空間に、
上記の溶融材料を射出し、
射出成形した成形体を脱バインダー処理して同
時に上記中子を加熱により分解消失させたのち、
上記成形体を焼結することを特徴とする筒状フエ
ライトの製造方法である。
図面に基づく発明の開示
この発明による製造方法を、フエライトからな
るロータリートランスコアの製造について具体的
に説明する。第１図はロータリートランスコアの
縦断面図、第２図はこの発明による射出成形用中
子の側面図である。
ロータリートランスコア１は円筒からなり、そ
の内周面の２箇所に全周にわたる溝２を周設した
形状からなる。
まず、ロータリートランスコアとしての特性を
得るのに必要な組成のフエライト原料の仮焼粉砕
粉末に、結合剤の有機材料を所要の混合比で加熱
混練し、押出し成形機で数ミリサイズのペレツト
となし、このペレツト成形材料を射出成形機内で
加熱溶融しておく。
つぎに、上記のコア１の外形を形成する所要形
状を有し焼結時の収縮率を考慮した寸法の外金型
を射出成形機に装着する。
一方、予め用意した熱膨張係数が６×10-5／℃
未満で150℃〜350℃の分解温度を有し、かつアタ
クチツクポリプロピレン及びポリスチレンあるい
は更にステアリン酸からなり、第２図に示す如く
上記のコア１の内周面凹形状に対向する外周凸形
状を有し、焼結時の収縮率を考慮した寸法からな
る中子３を、先に射出成形機内に装着した外金型
内に挿着する。
そして、外金型と中子３とによつて形成される
射出成形空間に上記の溶融材料を射出成形し、得
られた成形体を脱バインダー処理して同時に上記
中子３を加熱により分解消失させ、その後上記成
形体を焼結することにより所定のロータリートラ
ンスコアを得る。
つぎに、射出成形材料にソフトフエライトを用
いる場合のこの発明による中子の材料について説
明する。
一般に、ソフトフエライトは炭素の含有によ
り、その磁性特性、特に透磁率は著しく低下する
ので、中子として使用する有機材料は加熱時に完
全に揮発分解し、残留炭素がないことが必要であ
り、また、熱膨張係数は、６×10-5／℃未満であ
ると同時に、加熱時の容積変化が直線的である特
定の有機材料が、フエライト焼結体の亀裂あるい
は割れ、変形の防止に重要である。
中子を１種類の有機材料のみで成型すると、脱
バインダー処理時に、当該有機材料の分解が特定
の温度で急激に起るため、当該有機材料の膨脹あ
るいは急激な軟化による圧力等の影響で、成形体
の内周面の溝等に亀裂あるいは割れ、変形が生ず
る。
また、ポリエチレン、ポリプロピレン等は加熱
により、急激に膨脹するので、かかる中子材料と
しては好ましくない。
発明の効果
ところが、この発明による中子は、熱膨張係数
が６×10-5／℃未満であり、加熱時直線的容積変
化を起こし、150℃〜350℃の分解温度を有しか
つ、特定量のアタクチツクポリプロピレン及びポ
リスチレンあるいは更にステアリン酸の有機材料
を混合成形しているため、脱バインダー処理時に
中子の分解が徐々に進行して消失するので、成形
体の寸法精度の向上、安定化が計られるととも
に、亀裂、割れ、変形等が防止でき、生産性の向
上に極めて大きな効果がある。
発明の好ましい構成
この発明において、中子を構成する有機材料
は、ステアリン酸、アタクチツクポリプロピレン
（APP）、ポリスチレンは第１表に示す如く、熱
膨張係数が６×10-5／℃未満で分解温度が150℃
〜350℃を有し、かつ分解温度が異なる有機材料
を使用することができ、これを混合成型したもの
である。
また、この発明における中子は、APP30wt％
〜65wt％、ポリスチレン35wt〜70wt％からなる
もの、あるいはさらに、ステアリン酸35wt％以
下を配合したものである。
この発明による中子を使用した射出成形法によ
るソフトフエライト焼結体の残留炭素量は、通常
成形法による成形体の残留炭素量とほぼ同等であ
る。
この発明による中子を構成する有機材料の熱膨
張係数を限定した理由は、熱膨張係数が６×
10-5／℃以上になると、焼結体に亀裂及び割れを
発生し、製品歩留を低下するので好ましくないた
めである。
また、上記の中子の有機材料の分解温度を限定
した理由は、分解温度が150℃未満では有機材料
の融点が100℃以下と低くなりすぎ、射出成形に
より高精度な中子を製造することが困難となり、
350℃を越える分解温度を有する有機材料はその
融点が230℃以上と高くなりすぎ、中子を製造す
る通常の射出成形機では射出成形温度が高くなり
すぎ、量産化の点で好ましくないためである。
Field of Application This invention relates to a method of manufacturing a cylindrical ferrite material having a complicated inner peripheral surface, such as a cylindrical ferrite material for a rotary transformer core, by injection molding, and a core, in which a conventional inner mold is used during molding. The present invention relates to a method for manufacturing a cylindrical ferrite and a core for injection molding, in which the core used in the molding process has a specific composition and is decomposed and eliminated during the debinding treatment of the molded body, thereby facilitating manufacturing. Conventional technology Conventionally, products with complex irregularities on the inner circumferential surface, such as cylindrical ferrite for rotary transformer cores, were manufactured from a cylindrical ferrite material and then machined to form the complex shape of the inner circumferential surface. It involved a large number of steps and it was difficult to obtain a product of good quality. Therefore, injection molding methods, which can form complex shapes, have been used instead of machining. In general, the injection molding method for ferrite involves heating and kneading ferrite powder and an organic material at the desired mixing ratio, forming pellets in an extrusion molding machine, heating and melting this pellet molding material in the injection molding machine, and molding it into the desired shape and sintering it. This is a method in which the above-mentioned molten material is injected under pressure into an injection space formed by an outer mold and an inner mold whose dimensions take into account the shrinkage rate during molding to complete injection molding. Therefore, the pressure applied to the molded body becomes a three-dimensional pressure, which is more suitable for molding complex shapes than press molding using the uniaxial compression molding method. Problems with the Prior Art However, when injection molding something with a complicated shape such as the rotary transformer core mentioned above, which has a groove on the inner circumferential surface, the mold structure becomes very complicated.
The cost of the mold increased, and there were also various problems with the dimensional accuracy and mass productivity of the molded product. This invention provides a cylinder with such a complicated inner circumferential shape,
When manufacturing cylindrical ferrite such as square tubes, cylindrical shapes made by injection molding are easy to mold, have a simple mold structure, can be manufactured at low cost, have a good appearance and high dimensional accuracy, and are extremely effective for mass production. The purpose is a method for producing ferrite. Summary of the invention This invention melts a ferrite raw material for injection molding, and forms a mold with a thermal expansion coefficient of less than 6×10 -5 /°C of 150.
It has a decomposition temperature of °C to 350 °C, and is composed of 30 wt% to 65 wt% of atactic polypropylene (APP), 35 wt% to 70 wt% of polystyrene, or 35 wt% or less of stearic acid, and is made of an inner periphery of a cylindrical ferrite sintered body. The above molten material is injected into the injection molding space formed by the core having a convex shape on the outer periphery corresponding to the concave shape, and the injection molded body is subjected to a binder removal treatment, and at the same time, the above core is heated. After decomposing and disappearing,
This is a method for producing a cylindrical ferrite, characterized by sintering the above molded body. DISCLOSURE OF THE INVENTION BASED ON DRAWINGS The manufacturing method according to the present invention will be specifically explained for manufacturing a rotary transformer core made of ferrite. FIG. 1 is a longitudinal sectional view of a rotary transformer core, and FIG. 2 is a side view of an injection molding core according to the present invention. The rotary transformer core 1 is made of a cylinder, and has a shape in which grooves 2 extending all around the circumference are provided at two places on the inner circumferential surface. First, an organic material as a binder is heated and kneaded into a calcined and pulverized powder of a ferrite raw material with the composition necessary to obtain the characteristics of a rotary transformer core at the desired mixing ratio, and then formed into pellets of several millimeters in size using an extruder. None, this pellet molding material is heated and melted in an injection molding machine. Next, an outer mold having a required shape to form the outer shape of the core 1 described above and dimensions taking into account the shrinkage rate during sintering is mounted on an injection molding machine. On the other hand, the thermal expansion coefficient prepared in advance is 6×10 -5 /℃
It has a decomposition temperature of 150°C to 350°C at less than A core 3 having dimensions that take into account the shrinkage rate during sintering is inserted into an outer mold that has been previously installed in an injection molding machine. Then, the molten material is injected into the injection molding space formed by the outer mold and the core 3, the resulting molded body is subjected to a binder removal treatment, and at the same time the core 3 is decomposed and disappears by heating. The molded body is then sintered to obtain a predetermined rotary transformer core. Next, the material of the core according to the present invention when soft ferrite is used as the injection molding material will be explained. In general, the magnetic properties of soft ferrite, especially its magnetic permeability, are significantly reduced by the inclusion of carbon, so the organic material used as the core must completely volatilize and decompose when heated, and must have no residual carbon. A specific organic material that has a coefficient of thermal expansion of less than 6×10 -5 /°C and a linear volume change during heating is important for preventing cracks, splitting, and deformation of ferrite sintered bodies. be. If the core is molded from only one type of organic material, the decomposition of the organic material will occur rapidly at a certain temperature during the binder removal process. Cracks, cracks, and deformation occur in the grooves, etc. on the inner peripheral surface of the molded body. Further, polyethylene, polypropylene, etc. are not preferred as such core materials because they rapidly expand when heated. Effects of the Invention However, the core according to the present invention has a thermal expansion coefficient of less than 6×10 -5 /°C, causes a linear volume change when heated, has a decomposition temperature of 150°C to 350°C, and has a specific Since the organic materials such as atactic polypropylene and polystyrene or stearic acid are mixed and molded in a large amount, the core gradually decomposes and disappears during the binder removal process, improving the dimensional accuracy and stabilizing the molded product. It is possible to prevent cracks, cracks, deformation, etc., and is extremely effective in improving productivity. Preferred configuration of the invention In this invention, the organic materials constituting the core are stearic acid, atactic polypropylene (APP), and polystyrene has a thermal expansion coefficient of less than 6 x 10 -5 /°C and decomposes as shown in Table 1. temperature is 150℃
Organic materials having a temperature of ~350°C and different decomposition temperatures can be used, and these are mixed and molded. Moreover, the core in this invention is APP30wt%
~65wt%, polystyrene 35wt~70wt%, or further blended with stearic acid 35wt% or less. The amount of residual carbon in a soft ferrite sintered body produced by injection molding using the core according to the present invention is approximately the same as the amount of residual carbon in a molded body produced by a conventional molding method. The reason for limiting the thermal expansion coefficient of the organic material constituting the core according to this invention is that the thermal expansion coefficient is 6×
This is because if the temperature exceeds 10 -5 /°C, cracks and cracks will occur in the sintered body and the product yield will decrease, which is undesirable. In addition, the reason for limiting the decomposition temperature of the organic material in the core is that if the decomposition temperature is less than 150°C, the melting point of the organic material will be too low, below 100°C, and it is necessary to manufacture a high-precision core by injection molding. becomes difficult,
Organic materials with a decomposition temperature of over 350°C have a melting point of 230°C or higher, which makes the injection molding temperature too high in a normal injection molding machine for manufacturing cores, which is not desirable in terms of mass production. be.
【表】
実施例
以下にこの発明による実施例を示しその効果を
明らかにする。
まず、Ni−Znフエライトの仮焼粉砕粉末に、
結合剤としてポリエチレン等の有機材料を13wt
％添加して加熱混練し、押出し成形機で数ミリサ
イズのペレツトとなし、このペレツト成形材料を
射出成形機内で加熱溶融しておいた。
つぎに、前記した第１図のロータリートランス
コアの外形を形成する所要形状を有し焼結時の収
縮率を考慮した寸法の外金型を射出成形機に装着
した。
ステアリン酸（分解温度180℃）、APP（分解温
度240℃）、ポリスチレン（分解温度280℃）のう
ち２種あるいは３種の有機材料を含有し、第２表
に示す種々の組成からなり、前述した第２図に示
す如く第１図のロータリートランスコアの内周面
凹形状に対応する外周凸形状を有し、焼結時の収
縮率を考慮した寸法からなる中子を、先に射出成
形機内に装着した外金型内に挿着した。そして、
外金型と中子とによつて形成される射出成形空間
に上記の溶融材料を射出成形した。
得られた成形体を脱バインダー炉にて400℃ま
で毎日５℃の昇温速度で昇温し、脱バインダー処
理とともに上記中子を加熱により分解消失させ
た。
その後、この成形体を空気中、1250℃、２時間
の条件で焼結することにより第１図のロータリー
トランスコアを得た。
この発明による焼結体の磁気特性は通常成形法
による焼結体と同等であつた。
また、得られたロータリートランスコアの亀
裂、割れ状況及び寸法精度を測定した。その結果
を第２表に示す。
なお、亀裂、割れ状況は、コア内周面の溝部の
外観検査の結果であり、各試料No.の測定個数は
100個であつた。
また、寸法精度は、亀裂が割れの発生していな
い溝部の幅の標準偏差で表わし、寸法誤差規格は
0.05mm以下である。
第２表から明らかなように、本発明の試料No.１
〜５は、亀裂、割れ及び変形がなく、高寸法精度
のロータリートランスコアを得られたことがわか
る。[Table] Examples Examples according to the present invention will be shown below to clarify its effects. First, calcined and pulverized powder of Ni-Zn ferrite is
13wt of organic material such as polyethylene as a binder
% was added, heated and kneaded, and formed into pellets several millimeters in size using an extruder, and this pellet molding material was heated and melted in an injection molding machine. Next, an outer mold having the required shape to form the outer shape of the rotary transformer core shown in FIG. 1 and having dimensions taking into consideration the shrinkage rate during sintering was installed in an injection molding machine. Contains two or three types of organic materials among stearic acid (decomposition temperature 180℃), APP (decomposition temperature 240℃), and polystyrene (decomposition temperature 280℃), and has various compositions shown in Table 2. As shown in Fig. 2, a core having a convex outer periphery corresponding to the concave inner periphery of the rotary transformer core shown in Fig. 1 and having dimensions that take into account the shrinkage rate during sintering is first injection molded. It was inserted into an outer mold installed inside the machine. and,
The above molten material was injection molded into the injection molding space formed by the outer mold and the core. The temperature of the obtained molded body was raised to 400° C. at a rate of 5° C. every day in a binder removal furnace, and the core was decomposed and disappeared by heating while the binder was removed. Thereafter, this compact was sintered in air at 1250° C. for 2 hours to obtain the rotary transformer core shown in FIG. The magnetic properties of the sintered body according to the present invention were equivalent to those of the sintered body produced by the conventional molding method. In addition, cracks, crack conditions, and dimensional accuracy of the obtained rotary transformer core were measured. The results are shown in Table 2. The cracks and breakage conditions are the results of the visual inspection of the grooves on the inner peripheral surface of the core, and the number of pieces measured for each sample number is
There were 100 pieces. In addition, dimensional accuracy is expressed as the standard deviation of the width of the groove where no cracks occur, and the dimensional error standard is
It is 0.05mm or less. As is clear from Table 2, sample No. 1 of the present invention
It can be seen that samples No. 5 to 5 were free from cracks, cracks, and deformation, and a rotary transformer core with high dimensional accuracy was obtained.
第１図はロータリートランスコアの縦断面図、
第２図はこの発明による射出成形用中子の側面図
である。
図中、１……ロータリートランスコア、２……
溝部、３……中子。
Figure 1 is a vertical cross-sectional view of the rotary transformer core.
FIG. 2 is a side view of the injection molding core according to the present invention. In the figure, 1... rotary transformer core, 2...
Mizobe, 3...Nakako.
Claims (1)
と熱膨脹係数が６×10-5／℃未満で、150℃〜350
℃の分解温度を有し、かつアタクチツクポリプロ
ピレン（APP）30wt％〜65wt％、ポリスチレン
35wt％〜70wt％からなり、筒状ソフトフエライ
ト焼結体の内周面の凹形状に対応する凸状外周形
状を有する中子とによつて形成される射出成形空
間に、上記の溶融材料を射出し、射出成形した成
形体を脱バインダー処理して、同時に上記中子を
燃焼加熱により分解消失させたのち、上記成形体
を焼結することを特徴とする筒状フエライトの製
造方法。 ２ 射出成形用フエライト原料を溶融し、外金型
と熱膨脹係数が６×10-5／℃未満で、150℃〜350
℃の分解温度を有し、かつアタクチツクポリプロ
ピレン（APP）30wt％〜65wt％、ポリスチレン
35wt％〜70wt％、ステアリン酸35wt％以下から
なり、筒状ソフトフエライト焼結体の内周面の凹
形状に対応する凸状外周形状を有する中子とによ
つて、形成される射出成形空間に、上記の溶融材
料を射出し、射出成形した成形体を脱バインダー
処理して、同時に上記中子を燃焼加熱により分解
消失させたのち、上記成形体を焼結することを特
徴とする筒状フエライトの製造方法。 ３ 熱膨脹係数が６×10-5／℃未満で、150℃〜
350℃の分解温度を有し、かつアタクチツクポリ
プロピレン（APP）30wt％〜65wt％、ポリスチ
レン35wt％〜70wt％からなり、筒状フエライト
焼結体の内周面凹形状に対応する凸状外周形状を
有することを特徴とする筒状フエライトの射出成
形用中子。 ４ 熱膨脹係数が６×10-5／℃未満で、150℃〜
350℃の分解温度を有し、かつアタクチツクポリ
プロピレン（APP）30wt％〜65wt％、ポリスチ
レン35wt％〜70wt％、ステアリン酸35wt％以下
からなり、筒状フエライト焼結体の内周面凹形状
に対応する凸状外周形状を有することを特徴とす
る筒状フエライトの射出成形用中子。[Claims] 1. A ferrite raw material for injection molding is melted and the outer mold has a coefficient of thermal expansion of less than 6×10 -5 /°C, and a temperature of 150°C to 350°C.
Polystyrene with decomposition temperature of °C and atactic polypropylene (APP) 30wt%~65wt%
The above molten material is poured into an injection molding space formed by a core containing 35 wt% to 70 wt% and having a convex outer peripheral shape corresponding to the concave shape of the inner peripheral surface of the cylindrical soft ferrite sintered body. 1. A method for producing a cylindrical ferrite, which comprises removing the binder from an injection-molded molded body, simultaneously decomposing and eliminating the core by combustion heating, and then sintering the molded body. 2. Melt the ferrite raw material for injection molding, and the outer mold has a thermal expansion coefficient of less than 6 × 10 -5 / °C, and the temperature is 150 °C to 350 °C.
Polystyrene with decomposition temperature of °C and atactic polypropylene (APP) 30wt%~65wt%
35wt% to 70wt%, stearic acid 35wt% or less, and an injection molding space formed by a core having a convex outer peripheral shape corresponding to the concave shape of the inner peripheral surface of the cylindrical soft ferrite sintered body. The above molten material is injected, the injection molded molded body is subjected to a binder removal treatment, and at the same time, the core is decomposed and disappeared by combustion heating, and then the molded body is sintered. Method of manufacturing ferrite. 3 Thermal expansion coefficient is less than 6 × 10 -5 /℃, 150℃~
It has a decomposition temperature of 350℃ and is composed of 30wt% to 65wt% of atactic polypropylene (APP) and 35wt% to 70wt% of polystyrene, and has a convex outer peripheral shape that corresponds to the concave shape of the inner peripheral surface of the cylindrical ferrite sintered body. A cylindrical ferrite injection molding core characterized by having: 4 Thermal expansion coefficient is less than 6 × 10 -5 /℃, 150℃~
It has a decomposition temperature of 350℃ and is composed of 30wt% to 65wt% of atactic polypropylene (APP), 35wt% to 70wt% of polystyrene, and 35wt% or less of stearic acid, and has a concave shape on the inner peripheral surface of a cylindrical ferrite sintered body. A cylindrical ferrite injection molding core characterized by having a corresponding convex outer peripheral shape.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2037283A JPS59145104A (en) | 1983-02-09 | 1983-02-09 | Manufacture of cylindrical ceramics and core for injection molding |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2037283A JPS59145104A (en) | 1983-02-09 | 1983-02-09 | Manufacture of cylindrical ceramics and core for injection molding |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS59145104A JPS59145104A (en) | 1984-08-20 |
| JPH0140725B2 true JPH0140725B2 (en) | 1989-08-31 |
Family
ID=12025232
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2037283A Granted JPS59145104A (en) | 1983-02-09 | 1983-02-09 | Manufacture of cylindrical ceramics and core for injection molding |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59145104A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002155302A (en) * | 2000-09-05 | 2002-05-31 | Advanced Materials Technologies Pte Ltd | Method for forming hollow article |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6057598B2 (en) * | 2012-08-09 | 2017-01-11 | 株式会社キャステム | Method for producing sintered metal powder having hollow portion |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS50146605A (en) * | 1974-05-17 | 1975-11-25 | ||
| JPS5129170A (en) * | 1974-09-04 | 1976-03-12 | Matsushita Electric Ind Co Ltd | |
| JPS53113808A (en) * | 1977-03-16 | 1978-10-04 | Kaabon Seramu Kk | Method of manufacturing ringgshaped refractories with hollow opening |
-
1983
- 1983-02-09 JP JP2037283A patent/JPS59145104A/en active Granted
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS50146605A (en) * | 1974-05-17 | 1975-11-25 | ||
| JPS5129170A (en) * | 1974-09-04 | 1976-03-12 | Matsushita Electric Ind Co Ltd | |
| JPS53113808A (en) * | 1977-03-16 | 1978-10-04 | Kaabon Seramu Kk | Method of manufacturing ringgshaped refractories with hollow opening |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002155302A (en) * | 2000-09-05 | 2002-05-31 | Advanced Materials Technologies Pte Ltd | Method for forming hollow article |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS59145104A (en) | 1984-08-20 |
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