JPH1134113A - Injection mold - Google Patents

Injection mold

Info

Publication number
JPH1134113A
JPH1134113A JP18686797A JP18686797A JPH1134113A JP H1134113 A JPH1134113 A JP H1134113A JP 18686797 A JP18686797 A JP 18686797A JP 18686797 A JP18686797 A JP 18686797A JP H1134113 A JPH1134113 A JP H1134113A
Authority
JP
Japan
Prior art keywords
mold
surface layer
injection molding
injection
cavity
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.)
Pending
Application number
JP18686797A
Other languages
Japanese (ja)
Inventor
Sakae Takahashi
栄 高橋
Kimitaka Maruyama
公孝 丸山
Shuhei Honma
周平 本間
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Shibaura Machine Co Ltd
Original Assignee
Toshiba Machine Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Toshiba Machine Co Ltd filed Critical Toshiba Machine Co Ltd
Priority to JP18686797A priority Critical patent/JPH1134113A/en
Publication of JPH1134113A publication Critical patent/JPH1134113A/en
Pending legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
    • B29C45/17—Component parts, details or accessories; Auxiliary operations
    • B29C45/26—Moulds
    • B29C45/37—Mould cavity walls, i.e. the inner surface forming the mould cavity, e.g. linings

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • Manufacturing Optical Record Carriers (AREA)
  • Moulds For Moulding Plastics Or The Like (AREA)

Abstract

PROBLEM TO BE SOLVED: To make the cooling capacity after the filling with a molten resin excellent and to shorten a cycle time of injection molding. SOLUTION: This injection mold is constituted of two layers of matrix parts 1, 2 and two surface layer parts 3, 4. The matrix parts 1, 2 are formed of an S48C material and the surface layer parts 3, 4 of a cavity are formed of martensite stainless steel with a thickness of 3 mm. In this example, the surface layer parts 3, 4 are bonded to the matrix parts 1, 2 by soldering and, after bonding, tempering is applied to them and, further, finish processing is performed to finish the mold into a predetermined shape dimension.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【発明の属する技術分野】本発明は、射出成形において
使用される金型に係り、特に、ＣＤ（コンパクトディス
ク）、ＤＶＤ（ディジタルヴィデオディスク）などの高
度な寸法精度が要求されるプラスチック製品の射出成形
において使用される金型に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold used in injection molding, and more particularly to injection of plastic products such as CDs (compact discs) and DVDs (digital video discs) requiring high dimensional accuracy. It relates to a mold used in molding.

【０００２】[0002]

【従来の技術】従来、ＣＤ、ＤＶＤなどの高い寸法精度
が要求されるプラスチック製品を射出成形によって製造
する際に使用される金型として、マルテンサイト系ステ
ンレス鋼のＳＵＳ４２０Ｊ２が広く使用されている。Ｓ
ＵＳ４２０Ｊ２は、十分な機械的強度を備えるととも
に、機械加工性に優れているので鏡面加工が可能であ
り、プラスチックの射出成形用金型として要求される条
件を備えている。射出成形用金型を製造する場合、先
ず、ＳＵＳ４２０Ｊ２からなる素材を粗加工することに
よってキャビティ部を形成し、次に、そのキャビティ部
の表面に鏡面仕上げを施すことによってキャビティ表面
を形成する。なお、耐摩耗性及び離型性を高めるため
に、鏡面仕上げが施された上記キャビティ表面に、更
に、ＴｉＮなどでコーティングを施すことも行われてい
る。2. Description of the Related Art Conventionally, SUS420J2 of martensitic stainless steel has been widely used as a mold used for manufacturing plastic products such as CDs and DVDs requiring high dimensional accuracy by injection molding. S
US420J2 has sufficient mechanical strength and is excellent in machinability, so that it can be mirror-finished and has the conditions required for a plastic injection mold. When manufacturing an injection molding die, first, a cavity is formed by roughly processing a material made of SUS420J2, and then a cavity surface is formed by subjecting the surface of the cavity to mirror finishing. In addition, in order to enhance abrasion resistance and releasability, the mirror-finished cavity surface is further coated with TiN or the like.

【０００３】（従来の金型の問題点）射出成形用金型の
素材として使用される上記のＳＵＳ４２０Ｊ２は、熱伝
導率が２７Ｗ・ｍ-1・Ｋ-1と低い。このため、溶融樹脂
の充填後の冷却に長い時間がかかり、射出成形のサイク
ルタイムを増大させる主要な要因となっていた。(Problems with conventional molds) The above SUS420J2 used as a material for an injection mold has a low thermal conductivity of 27 W · m −1 · K −1 . For this reason, it takes a long time to cool after filling the molten resin, which has been a major factor in increasing the cycle time of injection molding.

【０００４】[0004]

【発明が解決しようとする課題】本発明は、以上の様な
従来の射出成形用金型の問題点を解決すべく成されたも
ので、本発明の目的は、溶融樹脂の充填後の冷却性能に
優れ、射出成形のサイクルタイムを短縮することが可能
な射出成形用金型を提供することにある。SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the conventional injection mold, and an object of the present invention is to provide cooling after filling with a molten resin. An object of the present invention is to provide an injection molding die having excellent performance and capable of shortening the cycle time of injection molding.

【０００５】[0005]

【課題を解決するための手段】本発明の射出成形用金型
は、プラスチックの射出成形に使用される射出成形用金
型であって、金型のキャビティの表層部分をマルテンサ
イト系ステンレス鋼で構成し、金型の母材部分を、前記
マルテンサイト系ステンレス鋼よりも熱伝導率が高い炭
素鋼または合金鋼で構成したことを特徴とする。An injection mold according to the present invention is an injection mold used for injection molding of plastics, wherein a surface layer of a cavity of the mold is made of martensitic stainless steel. The base material of the mold is made of carbon steel or alloy steel having a higher thermal conductivity than the martensitic stainless steel.

【０００６】好ましくは、前記母材部分を構成する炭素
鋼または合金鋼として、熱伝導率が４０Ｗｍ-1・Ｋ-1以
上の材料を使用する。好ましくは、前記表層部分の厚さ
を１ｍｍ以上、６ｍｍ以下とする。[0006] Preferably, a material having a thermal conductivity of 40 Wm -1 · K -1 or more is used as the carbon steel or alloy steel constituting the base material portion. Preferably, the thickness of the surface layer is 1 mm or more and 6 mm or less.

【０００７】好ましくは、前記表層部分をＳＵＳ４２０
Ｊ２で構成する。前記表層部分と前記母材部分との接合
は、例えば、ろう付けにより行うことができる。Preferably, the surface layer is made of SUS420.
J2. The joining between the surface layer portion and the base material portion can be performed by, for example, brazing.

【０００８】本発明の射出成形用金型によれば、金型の
キャビティの表層部分を、耐摩耗性を備え且つ機械加工
性に優れたマルテンサイト系ステンレス鋼で構成すると
ともに、金型の母材部分を、前記表層部分と比較して熱
伝導率が高い炭素鋼または合金鋼で構成しているので、
キャビティ内に溶融樹脂を充填した後の冷却速度が、従
来の様なマルテンサイト系ステンレス鋼の単一素材のみ
で構成された金型を使用した場合と比べて大きい。従っ
て、溶融樹脂の充填後、より速やかに型開きを行い、金
型から成形品を取り出すことができる。その結果、射出
成形の１サイクル当たりの時間が短縮され、生産性の向
上に効果がある。According to the injection mold of the present invention, the surface layer of the cavity of the mold is made of martensitic stainless steel having abrasion resistance and excellent machinability, and the base of the mold is formed. Since the material portion is made of carbon steel or alloy steel having a high thermal conductivity compared to the surface layer portion,
The cooling rate after the cavity is filled with the molten resin is higher than that of a conventional mold using only a single material of martensitic stainless steel. Therefore, after filling with the molten resin, the mold can be opened more quickly and the molded product can be taken out of the mold. As a result, the time per one cycle of the injection molding is reduced, which is effective in improving the productivity.

【０００９】[0009]

【発明の実施の形態】図１に、本発明に基づく射出成形
用金型の構造の一例を示す。この射出成形用金型は、コ
ア部が金型本体の中に収容された複合構造を備えてお
り、図中、１は固定側コア（母材部分）、２は移動側コ
ア（母材部分）、３は固定側コアの表層部分、４は移動
側コアの表層部分、７は固定側金型本体、８は移動側金
型本体を表す。固定側のコア１の表層部分３と移動側コ
ア２の表層部分４との間にキャビティ５が形成され、こ
のキャビティ５の中に溶融樹脂が充填される。なお、１
１は射出ノズルを表す。FIG. 1 shows an example of the structure of an injection mold according to the present invention. This injection molding die has a composite structure in which a core portion is housed in a die body. In the drawing, 1 is a fixed-side core (base material portion), and 2 is a moving-side core (base material portion). ), 3 is the surface layer of the fixed core, 4 is the surface layer of the movable core, 7 is the fixed mold body, and 8 is the movable mold body. A cavity 5 is formed between the surface layer 3 of the fixed core 1 and the surface layer 4 of the movable core 2, and the cavity 5 is filled with a molten resin. In addition, 1
1 represents an injection nozzle.

【００１０】次に、図１に示した射出成形用金型の固定
側コア１及び移動側コア２の製造方法の一例について説
明する。固定側コア１及び移動側コア２の母材部分を、
Ｓ４８Ｃ材（熱伝導率：約５０Ｗ・ｍ-1・Ｋ-1）を加工
して作成するとともに、板厚３ｍｍのマルテンサイト系
ステンレス鋼（ウッデホルム社製、商品名：ＳＴＡＶＡ
Ｘ）を加工して、キャビティ５の表層部分３、４の形状
を備えた部材を作成した。Next, an example of a method for manufacturing the fixed core 1 and the movable core 2 of the injection mold shown in FIG. 1 will be described. The base material portions of the fixed core 1 and the movable core 2 are
S48C material (thermal conductivity: about 50 W · m −1 · K −1 ) was prepared and processed, and a 3 mm-thick martensitic stainless steel (manufactured by Wooddeholm Co., Ltd., trade name: STAVA)
X) was processed to form a member having the shape of the surface portions 3 and 4 of the cavity 5.

【００１１】次に、前記母材部分のキャビティ相当部分
の表面に、前記部材をろう付けによって接合した。な
お、ろう材としてＢＮｉ−２（ＪＩＳ）を使用し、ろう
付温度は１０７０℃とした。Next, the member was joined by brazing to the surface of the base material portion corresponding to the cavity. In addition, BNi-2 (JIS) was used as the brazing material, and the brazing temperature was 1070 ° C.

【００１２】ろう付け後、金型を真空炉の中で加熱し、
次いで、同真空炉内で強制空冷により焼入れを施した。
焼入れ後の表層部分３、４の硬度はＨＲＣ５３であっ
た。その後、更に仕上加工を行って、所定の形状寸法を
備えた金型を完成した。After brazing, the mold is heated in a vacuum furnace,
Next, quenching was performed by forced air cooling in the same vacuum furnace.
The hardness of the surface portions 3 and 4 after quenching was HRC53. Thereafter, finishing was further performed to complete a mold having a predetermined shape and size.

【００１３】なお、表層部分３、４の厚さについては、
薄い方が金型全体の冷却性能が高くなるが、薄過ぎると
冷却性能が高過ぎて、熱応力に起因する成形品の内部応
力が増大し、反りなどが発生して好ましくない。また、
成形品がＣＤあるいはＤＶＤの場合、内部応力の増大に
伴い複屈折が大きくなり、また、情報信号であるピット
の転写性も低下する。一方、表層部分が厚みを増やし過
ぎると、冷却性能の改善効果が減少するので、サイクル
タイム短縮の効果が現れない、従って、表層部分の厚み
としては、１〜６ｍｍ程度が適当である。The thicknesses of the surface portions 3 and 4 are as follows.
The thinner the mold, the higher the cooling performance of the whole mold. However, if the thickness is too thin, the cooling performance is too high, and the internal stress of the molded article due to the thermal stress increases, which is not preferable because warpage occurs. Also,
When the molded product is a CD or a DVD, the birefringence increases as the internal stress increases, and the transferability of pits, which are information signals, also decreases. On the other hand, if the thickness of the surface layer is excessively increased, the effect of improving the cooling performance is reduced, so that the effect of shortening the cycle time does not appear. Therefore, the thickness of the surface layer is suitably about 1 to 6 mm.

【００１４】上記の方法で作成された金型を用い、ＤＶ
Ｄ（直径１２０ｍｍ、板厚０．６ｍｍ）の射出成形テス
トを行ったところ、３．６８秒のサイクルタイムが実現
された。なお、母材部分及び表層部分が単一素材（ＳＵ
Ｓ４２０Ｊ２）によって構成された従来の金型の場合の
サイクルタイムは、４．２１秒であったので、生産性が
約１３％向上したことになる。なお、上記のサイクルタ
イムの短縮に伴い、反り、複屈折、転写性などの性能の
低下は認められなかった。Using the mold prepared by the above method, the DV
When an injection molding test of D (diameter 120 mm, plate thickness 0.6 mm) was performed, a cycle time of 3.68 seconds was realized. The base material and the surface layer are made of a single material (SU
Since the cycle time of the conventional mold constituted by S420J2) was 4.21 seconds, the productivity was improved by about 13%. No reduction in performance such as warpage, birefringence and transferability was observed with the shortening of the cycle time.

【００１５】[0015]

【発明の効果】本発明の射出成形用金型によれば、金型
のキャビティの表層部分を耐摩耗性を備え且つ機械加工
性に優れた材料で構成するとともに、金型の母材部分を
前記表層部分と比較して熱伝導率が高い材料で構成して
いるので、溶融樹脂を充填した後の冷却速度が、従来の
単一材料のみで構成された金型を使用した場合と比較し
て大きく、従って、溶融樹脂の充填後、より速やかに型
開きを行い、金型から成形品を取り出すことができる。
その結果、射出成形の１サイクル当たりの時間が短縮さ
れ、生産性の向上に効果がある。According to the injection molding die of the present invention, the surface portion of the cavity of the die is made of a material having abrasion resistance and excellent in machinability, and the base material of the die is formed of a material. Since it is composed of a material having a high thermal conductivity as compared to the surface layer portion, the cooling rate after filling the molten resin is lower than that in a case where a mold composed of only a conventional single material is used. Therefore, after the molten resin is filled, the mold can be opened more quickly and the molded product can be taken out of the mold.
As a result, the time per one cycle of the injection molding is reduced, which is effective in improving the productivity.

【図面の簡単な説明】[Brief description of the drawings]

【図１】本発明に基づく射出成形用金型の構造の一例を
示す断面図。FIG. 1 is a sectional view showing an example of the structure of an injection mold according to the present invention.

【符号の説明】[Explanation of symbols]

１・・・固定側コア（母材部分）、 ２・・・移動側コア（母材部分）、 ３・・・表層部分、 ４・・・表層部分、 ５・・・キャビティ、 ７・・・固定側金型本体、 ８・・・移動側金型本体、 １１・・・射出ノズル。 DESCRIPTION OF SYMBOLS 1 ... Fixed side core (base material part) 2 ... Moving side core (base material part) 3 ... Surface layer part 4 ... Surface layer part 5 ... Cavity 7 ... Fixed mold body, 8: Moving mold body, 11: Injection nozzle.

Claims (5)

【特許請求の範囲】[Claims] 【請求項１】 プラスチックの射出成形に使用される射
出成形用金型であって、 金型のキャビティの表層部分をマルテンサイト系ステン
レス鋼で構成し、 金型の母材部分を、前記マルテンサイト系ステンレス鋼
よりも熱伝導率が高い炭素鋼または合金鋼で構成したこ
とを特徴とする射出成形用金型。1. A mold for injection molding used for injection molding of plastic, wherein a surface portion of a cavity of the mold is formed of martensitic stainless steel, and a base material of the mold is formed of the martensite. An injection molding die comprising a carbon steel or an alloy steel having a higher thermal conductivity than a series stainless steel. 【請求項２】 前記母材部分の熱伝導率は、４０Ｗ・ｍ
-1・Ｋ-1以上であることを特徴とする請求項１に記載の
射出成形用金型。2. The thermal conductivity of the base material portion is 40 W · m.
2. The injection mold according to claim 1 , wherein the value is -1.K- 1 or more. 【請求項３】 前記表層部分の厚みは、１ｍｍ以上、６
ｍｍ以下であることを特徴とする請求項１に記載の射出
成形用金型。3. The thickness of the surface layer is 1 mm or more and 6
The injection mold according to claim 1, wherein the diameter is not more than mm. 【請求項４】 前記表層部分は、ＳＵＳ４２０Ｊ２で構
成されることを特徴とする請求項１に記載の射出成形用
金型。4. The injection mold according to claim 1, wherein the surface layer is made of SUS420J2. 【請求項５】 前記表層部分は、ろう付によって前記母
材部分に接合されていることを特徴とする請求項１に記
載の射出成形用金型。5. The injection molding die according to claim 1, wherein the surface layer is joined to the base material by brazing.
JP18686797A 1997-07-11 1997-07-11 Injection mold Pending JPH1134113A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP18686797A JPH1134113A (en) 1997-07-11 1997-07-11 Injection mold

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP18686797A JPH1134113A (en) 1997-07-11 1997-07-11 Injection mold

Publications (1)

Publication Number Publication Date
JPH1134113A true JPH1134113A (en) 1999-02-09

Family

ID=16196068

Family Applications (1)

Application Number Title Priority Date Filing Date
JP18686797A Pending JPH1134113A (en) 1997-07-11 1997-07-11 Injection mold

Country Status (1)

Country Link
JP (1) JPH1134113A (en)

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