JP3362905B2 - Injection molding method - Google Patents
Injection molding methodInfo
- Publication number
- JP3362905B2 JP3362905B2 JP6792293A JP6792293A JP3362905B2 JP 3362905 B2 JP3362905 B2 JP 3362905B2 JP 6792293 A JP6792293 A JP 6792293A JP 6792293 A JP6792293 A JP 6792293A JP 3362905 B2 JP3362905 B2 JP 3362905B2
- Authority
- JP
- Japan
- Prior art keywords
- resin
- injection molding
- gas
- injected
- molding method
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Landscapes
- Moulds For Moulding Plastics Or The Like (AREA)
- Injection Moulding Of Plastics Or The Like (AREA)
- Blow-Moulding Or Thermoforming Of Plastics Or The Like (AREA)
Description
【発明の詳細な説明】
【０００１】
【産業上の利用分野】本発明は、円筒形状構造物の外面
に螺旋状に中空パイプを配置した形状の熱可塑性樹脂製
成形品の射出成形方法に関する発明である。本発明によ
り得られる成形品は、例えば円筒内部に気体あるいは流
体を通し円筒外面に設けられた螺旋状中空パイプ部分
に、熱媒あるいは冷媒を通すことにより円筒内部の気体
あるいは流体を加熱あるいは冷却できる簡易熱交換器等
に使用することができる。
【０００２】
【従来の技術】従来の射出成形において、本形状のよう
な成形品を製造する場合、溶融金属あるいは、水溶性樹
脂を使用して、予め中空部分の形状をつくり、成形時に
金型内に挿入しておき、成形後、内部の溶融金属を溶融
あるいは、水溶性樹脂を溶解させ中空構造をつくる方法
があるが、これらの方法では、予め中空部分になる形状
を成形しておく必要があるまた螺旋状構造の挿入部品を
適切な位置に固定するなどかなり複雑な製造工程を必要
とする。
【０００３】
【発明が解決しようとする課題】本発明の目的は、予め
成形した溶融中子等を用いることなく一度の射出成形に
より、円筒形状構造物の外面に螺旋状に中空パイプ部分
が配置された成形品の射出成形方法を提供することにあ
る。
【０００４】
【課題を解決するための手段】本発明者らは、上記課題
を解決するため鋭意検討した結果、円筒部分の肉厚と中
空パイプ部分の断面形状の比率を、適切に選択するこ
と、及び中空パイプ部分の末端に延長部部分を設け、他
の末端に樹脂注入部分及びガス注入口を設け、溶融した
樹脂をキャビティ内に必要量射出し、その射出過程中に
加圧ガス体を注入し、中空パイプ部分の延長した部分を
切断することにより、円筒形状の外面に螺旋状の中空パ
イプ構造を設けた円筒形状の成形品を成形することが可
能であることを見出し本発明を完成させた。
【０００５】すなわち、本発明は、円筒形状構造物の周
囲に螺旋状の中空パイプ状部分が設けられた形状の成形
品の射出成形法であって、円筒形状構造物の周囲に螺旋
部分が設けられた金型キャビティに、該螺旋部分の末端
の樹脂ゲートより溶融樹脂を必要量射出し、キャビティ
部分に溶融樹脂が充填される以前に樹脂ゲート近傍より
圧縮ガスを注入し、螺旋部分に連続した中空パイプ状部
分を形成することを特徴とする円筒形状構造物の射出成
形方法に関する発明である。
【０００６】本発明において、本形状の成形品を形成す
る樹脂として、通常の熱可塑性樹脂すなわちポリオレフ
ィン、ポリスチレン、ＡＢＳ樹脂、ＡＳ樹脂、メタクリ
ル樹脂、含フッソ樹脂等で例示される汎用の熱可塑性樹
脂はもとよりポリアミド、飽和ポリエステル、ポリカ−
ボネ−ト、ポリアクリレ−ト、ポリアセタ−ル、ポリス
ルホン、変性ポリレニレンエ−テル等で例示されるいわ
ゆるエンジニアリングプラスチックスをも使用すること
ができる。
【０００７】本発明方法の好ましい成形方法を以下に述
べる。円筒形状構造物の外面に螺旋状に配置されたパイ
プ状部分の一方の端部を延長した部位より樹脂及びガス
を注入するが、樹脂及びガスを注入し他方のパイプ末端
の延長部分は、パイプ部分の全体積の５％以上の体積に
なるように延長する。これは、使用するパイプ部分の末
端部まで中空構造が均一になるようにするために必要だ
からである。又、断面形状における中空パイプ部分の肉
厚は、パイプを形成する円筒形状構造物の肉厚の５〜１
０倍であるのが望ましい。上記肉厚の比率の場合に螺旋
状部分に中空部が好適に形成される。
【０００８】上記のように設計した金型キャビティ内に
射出成形機シリンダ−内で溶融した熱可塑性樹脂を、所
定量計量したのち、射出注入する。ただし、この溶融樹
脂の量は金型キャビティを完全に充填するに足りない量
であり、かつ加圧ガス体が注入された場合にキャビティ
内を充填するに充分な量である。
【０００９】前記溶融した熱可塑性樹脂が該キャビティ
内にすべての樹脂の注入が終了する前に加圧ガス体を金
型内に設けられたガスノズルを介して金型キャビティに
設けられたガスゲ−トを介して製品キャビティ内に注入
する。加圧ガスとしては、通常窒素ガスを使用するのが
好ましい。該溶融した熱可塑性樹脂は、加圧ガスにより
押し延ばされながら金型内に設けられた螺旋上パイプ部
部分を流路として流れる。その際にパイプ部分より円筒
部分に樹脂がはみ出し円筒部分が形成される。溶融樹脂
は、末端まで加圧ガス体により押し延ばされパイプ部分
内部に連続した中空部が形成される。該溶融樹脂が冷却
固化した後、中空部分の圧力を大気圧とし型開きを行っ
て、製品を取り出す。
【００１０】次に中空パイプ部分の末端部分を、機械加
工で切削して、連続した中空パイプ状は円筒部分の外面
に形成された製品を得る。
【００１１】
【実施例】以下本発明を実施例に基づき説明する。外径
４０φ、内径３８φ長さ２００ｍｍの円筒の外形に幅９
ｍｍ、高さ９ｍｍのガスチャンネルを螺旋状に巻き付け
た様な形状のチャンネル一端を２０ｍｍ延長し、樹脂ゲ
−ト及びガス注入部位を設ける。他方の端部にチャンネ
ル全体積の１０％に成るようにガスチャンネルを延長す
る。この様なキャビティ形状の金型を使用し、ポリカ−
ボネ−ト（三菱ガス化学（株）製、商品名：ユ−ピロン
Ｓ３０００）をキャビティ容積の６０〜７０％を満たす
ように射出した。射出の際のシリンダ−内の溶融樹脂の
温度は、２９０℃、射出圧力は８０ＭＰａであった。こ
の際樹脂射出終了前に樹脂ゲ−トと同一端部にあるガス
注入部位より窒素ガスを圧入した。溶融樹脂は窒素ガス
により押し出されキャビティ内部の４０φの円筒部分の
端部まで充填した後、窒素ガスの圧力５ＭＰａで保持し
た状態で樹脂を冷却した。成形品中空部の窒素ガス圧を
大気圧まで下げて離型後、成形品を取り出した。該成形
品の各端部を切断し、連続した螺旋状の中空パイプ部部
分が円筒形状構造物の外周部分に配置された製品を得
た。
【００１２】
【発明の効果】本発明によれば、従来、溶融中子法など
で製造していた製品が、通常の金型構造で、射出成形に
て成形できるため、短時間で多量の同一品が得られ、生
産性も向上する。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding method of a thermoplastic resin molded article having a hollow pipe spirally arranged on the outer surface of a cylindrical structure. It is. The molded article obtained by the present invention can heat or cool the gas or fluid inside the cylinder by passing a heat medium or a refrigerant through a helical hollow pipe portion provided on the outer surface of the cylinder, for example, by passing a gas or fluid inside the cylinder. It can be used for simple heat exchangers and the like. 2. Description of the Related Art In a conventional injection molding, when manufacturing a molded article having the shape of the present invention, a hollow portion is formed in advance using a molten metal or a water-soluble resin, and a mold is formed at the time of molding. After molding, there is a method of melting the internal molten metal or dissolving the water-soluble resin to create a hollow structure.However, in these methods, it is necessary to shape the hollow part in advance However, it requires a rather complicated manufacturing process, such as fixing the insert having a spiral structure in an appropriate position. [0003] An object of the present invention is to arrange a hollow pipe portion spirally on the outer surface of a cylindrical structure by one injection molding without using a preformed molten core or the like. To provide an injection molding method for a molded article. The inventors of the present invention have made intensive studies to solve the above-mentioned problems, and as a result, have appropriately selected the ratio of the thickness of the cylindrical portion to the cross-sectional shape of the hollow pipe portion. An extension portion is provided at the end of the hollow pipe portion, a resin injection portion and a gas injection port are provided at the other end, and a required amount of molten resin is injected into the cavity, and a pressurized gas body is injected during the injection process. By injecting and cutting the extended portion of the hollow pipe portion, it was found that it was possible to form a cylindrical molded product having a spiral hollow pipe structure on the cylindrical outer surface, and completed the present invention. I let it. That is, the present invention relates to an injection molding method of a molded article having a spiral hollow pipe-shaped portion provided around a cylindrical structure, wherein the spiral portion is provided around the cylindrical structure. A required amount of molten resin is injected from the resin gate at the end of the spiral portion into the mold cavity thus obtained, and a compressed gas is injected from the vicinity of the resin gate before the molten resin is filled into the cavity portion, and is continuously connected to the spiral portion. The present invention relates to an injection molding method for a cylindrical structure, wherein a hollow pipe-shaped portion is formed. [0006] In the present invention, as the resin forming the molded article of this shape, a general thermoplastic resin, that is, a general-purpose thermoplastic resin exemplified by polyolefin, polystyrene, ABS resin, AS resin, methacrylic resin, fluorinated resin and the like. Of course, polyamide, saturated polyester, polycarbonate
So-called engineering plastics exemplified by bone, polyacrylate, polyacetal, polysulfone, modified polyrenylene ether and the like can also be used. The preferred molding method of the present invention is described below. Resin and gas are injected from a portion of one end of the pipe-shaped portion spirally arranged on the outer surface of the cylindrical structure, and the other end of the pipe is injected with resin and gas. Extend to a volume of at least 5% of the total volume of the part. This is because it is necessary to make the hollow structure uniform up to the end of the pipe section to be used. The thickness of the hollow pipe portion in the cross-sectional shape is 5 to 1 times the thickness of the cylindrical structure forming the pipe.
Desirably, it is 0 times. In the case of the above thickness ratio, a hollow portion is suitably formed in the spiral portion. A thermoplastic resin melted in a cylinder of an injection molding machine is weighed in a predetermined amount into the mold cavity designed as described above, and then injected. However, the amount of the molten resin is insufficient to completely fill the mold cavity, and is sufficient to fill the cavity when the pressurized gas is injected. Before the molten thermoplastic resin is completely injected into the cavity, a pressurized gas body is supplied to a gas gate provided in the mold cavity via a gas nozzle provided in the mold. And into the product cavity. Normally, it is preferable to use nitrogen gas as the pressurized gas. The molten thermoplastic resin flows through the spiral pipe portion provided in the mold as a flow path while being stretched by the pressurized gas. At that time, the resin protrudes from the pipe portion to the cylindrical portion to form a cylindrical portion. The molten resin is pushed to the end by the pressurized gas body, and a continuous hollow portion is formed inside the pipe portion. After the molten resin is cooled and solidified, the pressure in the hollow portion is set to the atmospheric pressure, the mold is opened, and the product is taken out. Next, the end portion of the hollow pipe portion is cut by machining to obtain a product in which a continuous hollow pipe shape is formed on the outer surface of the cylindrical portion. Hereinafter, the present invention will be described with reference to examples. Outer diameter 40φ, Inner diameter 38φ Length of 200mm cylinder
A gas channel having a height of 9 mm and a height of 9 mm is spirally wound and one end of the channel is extended by 20 mm to provide a resin gate and a gas injection site. At the other end extend the gas channel to 10% of the total volume of the channel. Using a mold with such a cavity shape, a polycarbonate
A bone (Mitsubishi Gas Chemical Co., Ltd., trade name: Iupilon S3000) was injected so as to fill 60 to 70% of the cavity volume. The temperature of the molten resin in the cylinder at the time of injection was 290 ° C., and the injection pressure was 80 MPa. At this time, before the end of resin injection, nitrogen gas was injected under pressure from a gas injection site at the same end as the resin gate. The molten resin was extruded by the nitrogen gas and filled up to the end of the 40φ cylindrical portion inside the cavity, and then cooled while maintaining the nitrogen gas pressure at 5 MPa. After releasing the mold by lowering the nitrogen gas pressure in the hollow part of the molded article to the atmospheric pressure, the molded article was taken out. Each end of the molded product was cut to obtain a product in which a continuous spiral hollow pipe portion was disposed on the outer peripheral portion of the cylindrical structure. According to the present invention, since a product conventionally manufactured by a molten core method or the like can be formed by injection molding with a normal mold structure, a large amount of the same product can be manufactured in a short time. Product is obtained, and productivity is improved.
【図面の簡単な説明】
【図１】 本発明の方法により成形された円筒形状構造
物の外周部分に螺旋状にパイプが配置された製品の外形
図である。
【符号の説明】
１：樹脂ゲ−ト位置
２：ガス注入位置BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an external view of a product in which a pipe is spirally arranged on an outer peripheral portion of a cylindrical structure formed by the method of the present invention. [Explanation of Signs] 1: Resin gate position 2: Gas injection position
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭59−202822（ＪＰ，Ａ) 特開 昭60−18333（ＪＰ，Ａ) 特開 昭60−136688（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) B29C 49/06 - 49/80 B29C 45/00 - 45/84 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-59-202822 (JP, A) JP-A-60-18333 (JP, A) JP-A-60-136688 (JP, A) (58) Field (Int.Cl. 7 , DB name) B29C 49/06-49/80 B29C 45/00-45/84
Claims (1)
イプ状部分が設けられた形状の成形品の射出成形法であ
って、円筒形状構造物の周囲に螺旋部分が設けられた金
型キャビティに、該螺旋部分の末端の樹脂ゲートより溶
融樹脂を必要量射出し、キャビティ部分に溶融樹脂が充
填される以前に樹脂ゲート近傍より圧縮ガスを注入し、
螺旋部分に連続した中空パイプ状部分を形成することを
特徴とする円筒形状構造物の射出成形方法。(57) [Claim 1] An injection molding method for a molded article having a shape in which a helical hollow pipe-like portion is provided around a cylindrical structure, the method comprising: To the mold cavity provided with a spiral portion, a required amount of molten resin is injected from a resin gate at the end of the spiral portion, and a compressed gas is injected from the vicinity of the resin gate before the cavity portion is filled with the molten resin,
An injection molding method for a cylindrical structure, wherein a hollow pipe-shaped portion continuous to a spiral portion is formed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6792293A JP3362905B2 (en) | 1993-03-26 | 1993-03-26 | Injection molding method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6792293A JP3362905B2 (en) | 1993-03-26 | 1993-03-26 | Injection molding method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH06278156A JPH06278156A (en) | 1994-10-04 |
| JP3362905B2 true JP3362905B2 (en) | 2003-01-07 |
Family
ID=13358897
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6792293A Expired - Fee Related JP3362905B2 (en) | 1993-03-26 | 1993-03-26 | Injection molding method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3362905B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1848576A1 (en) * | 2005-02-11 | 2007-10-31 | 3M Innovative Properties Company | Method of processing polycarbonate with supercritical fluids |
| CN109333966A (en) * | 2018-11-20 | 2019-02-15 | 上海公元建材发展有限公司 | A kind of production of FRPP reinforcement tubing extrusion molding mould and production method |
-
1993
- 1993-03-26 JP JP6792293A patent/JP3362905B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH06278156A (en) | 1994-10-04 |
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