JPH0839645A - Molding of substrate for optical disk - Google Patents

Molding of substrate for optical disk

Info

Publication number
JPH0839645A
JPH0839645A JP17535994A JP17535994A JPH0839645A JP H0839645 A JPH0839645 A JP H0839645A JP 17535994 A JP17535994 A JP 17535994A JP 17535994 A JP17535994 A JP 17535994A JP H0839645 A JPH0839645 A JP H0839645A
Authority
JP
Japan
Prior art keywords
cavity
mold
opening amount
substrate
open quantity
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
JP17535994A
Other languages
Japanese (ja)
Inventor
Takanori Tamura
孝憲 田村
Shoji Yokota
章司 横田
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.)
Mitsubishi Chemical Corp
Original Assignee
Mitsubishi Chemical Corp
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 Mitsubishi Chemical Corp filed Critical Mitsubishi Chemical Corp
Priority to JP17535994A priority Critical patent/JPH0839645A/en
Publication of JPH0839645A publication Critical patent/JPH0839645A/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
    • B29C45/263—Moulds with mould wall parts provided with fine grooves or impressions, e.g. for record discs

Abstract

PURPOSE:To obtain a substrate reduced in the irregularity of double refraction between substrates by performing cooling while changing the open quantity of a cavity when the resin in the cavity is cooled and controlling the open quantity to preset one corresponding to an elapse time after the introduction of a molten resin is completed. CONSTITUTION:When the resin in a cavity 3 is cooled, cooling is performed while the open quantity of the cavity 3 is changed. The control of the open quantity of the cavity is performed, for example, on the basis of the valve operation signal of an injection nozzle at a point of time when the introduction of a molten resin into the cavity 3 is completed. The open quantity of the cavity 3 is controlled, for example, by measuring the open quantity (t) of a movable mold 1 and a fixed mold 2 by a mold opening sensor 6 and inputting the measuring signal of the sensor 6 to an operation device 7. The deviation with the open quantity set value of the cavity preliminarily stored in the operation device 7 is outputted to a mold clamping device 8 from the operation device 7. The mold clamping pressure of a mold clamping device 8 is changed on the basis of the control signal thereof to control the predetermined open quantity of the cavity.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】本発明は、光ディスク用基板の成
形方法に係わり、特に、基板表面の複屈折の小さい光デ
ィスク用基板の成形方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for molding an optical disk substrate, and more particularly to a method for molding an optical disk substrate having a substrate surface with a small birefringence.

【０００２】[0002]

【従来の技術】近年、大容量、高速のメモリ媒体として
光記録媒体が注目されている。光記録媒体としては再生
専用型光ディスク（ＣＤ，ＶＤ，ＣＤ−ＲＯＭ等），記
録再生型光ディスク（ライトワンス型），記録，再生，
消去，再書込可能型光ディスク（リライタブル型）等が
知られている。これらの光記録媒体の基板としては一般
に樹脂基板（ポリカーボネート樹脂，アクリル樹脂等）
が用いられている。2. Description of the Related Art In recent years, an optical recording medium has attracted attention as a large-capacity, high-speed memory medium. As the optical recording medium, a read-only optical disc (CD, VD, CD-ROM, etc.), a recording / playback optical disc (write-once type), recording, playback,
An erasable and rewritable optical disc (rewritable type) and the like are known. As a substrate for these optical recording media, a resin substrate (polycarbonate resin, acrylic resin, etc.) is generally used.
Is used.

【０００３】これらのディスク基板は生産性の面から通
常、射出成形法や射出圧縮成形法を用いて形成されてい
る。すなわち、固定金型と可動金型との間に型締め状態
で形成されるキャビティー内に環状で平坦なスタンパー
を取付け、キャビティー内に溶融樹脂材を射出すること
によってスタンパーの信号（ピット）やトラッキング用
案内溝等を転写した偏平なディスク基板が成形される。
ディスク基板成形時において、キャビティー内への溶融
樹脂充填後の保圧工程から冷却工程中に金型間の型締力
を一定にして保持する方法や、型締力を変化させて成形
することが提案されている。[0003] These disk substrates are usually formed by injection molding or injection compression molding in terms of productivity. That is, a ring-shaped flat stamper is installed in a cavity formed in a mold clamped state between a fixed mold and a movable mold, and a molten resin material is injected into the cavity to generate a signal (pit) of the stamper. A flat disk substrate on which the tracking guide groove and the like are transferred is molded.
When molding a disk substrate, a method of holding the mold clamping force between molds constant during the holding process after the molten resin is filled in the cavity and the cooling process, or molding by changing the mold clamping force. Is proposed.

【０００４】[0004]

【発明が解決しようとする課題】しかしながら、上記提
案法のようにディスク基板成形の際、金型間のキャビテ
ィー内への溶融樹脂充填後の保圧工程から冷却工程中に
金型間の型締力を一定に保ったり、型締力をある程度変
化させる方法では、得られたディスク基板の複屈折が得
られた基板間で大きく変わる（バラツク）という問題が
あることが判明した。However, when molding a disk substrate as in the above-mentioned proposed method, the mold between the molds is changed from the pressure-holding process after the molten resin is filled into the cavity between the molds to the cooling process. It has been found that the method of keeping the clamping force constant or changing the mold clamping force to some extent has a problem that the birefringence of the obtained disk substrate greatly changes (varies) between the obtained substrates.

【０００５】該基板の複屈折が大きくなるとＣ／Ｎ比が
低下し、光学的特性が低下して実用上問題となるので、
基板の複屈折は出来るかぎり小さく、且つ基板間のバラ
ツキも小さい事が望まれる。本発明の目的は、基板成形
時における基板間の複屈折のバラツキの小さい光ディス
ク用基板の成形法を提供することにある。When the birefringence of the substrate increases, the C / N ratio decreases, and the optical characteristics deteriorate, which is a problem in practical use.
It is desired that the birefringence of the substrate is as small as possible and the variation between the substrates is also small. An object of the present invention is to provide a method for forming a substrate for an optical disc, in which variations in birefringence between the substrates at the time of forming the substrate are small.

【０００６】[0006]

【課題を解決するための手段】本発明の要旨は、金型の
キャビティー内にプリフォーマット情報を有するスタン
パーを取り付け、キャビティー内に溶融樹脂を導入して
プリフォーマット情報が転写された光ディスク用基板を
成形する方法において、キャビティー内の樹脂を冷却す
る際にキャビティーの開き量を変化させつつ冷却を行
い、キャビティーの開き量は、溶融樹脂の導入終了後、
経過時間に応じ、予め設定された開き量に制御すること
を特徴とする光ディスク用基板の成形方法に存する。DISCLOSURE OF THE INVENTION The gist of the present invention is for an optical disc in which a stamper having preformat information is attached in a cavity of a mold and a molten resin is introduced into the cavity to transfer the preformat information. In the method of molding the substrate, when the resin in the cavity is cooled, cooling is performed while changing the opening amount of the cavity, and the opening amount of the cavity is after the introduction of the molten resin,
A method of molding an optical disk substrate is characterized by controlling the opening amount to be set in advance according to the elapsed time.

【０００７】以下、本発明の光ディスク用基板成形法に
つき詳細に説明する。図１には本発明の光ディスク用基
板成形法を実施する成形装置が示されている。この成形
装置は可動側金型１と固定側金型２とを含み、可動側金
型１には基板表面にピットやレーザー案内溝を転写する
ためのスタンパー４が固定されている。The optical disk substrate molding method of the present invention will be described in detail below. FIG. 1 shows a molding apparatus for carrying out the optical disk substrate molding method of the present invention. This molding apparatus includes a movable side mold 1 and a fixed side mold 2, and a stamper 4 for transferring pits and laser guide grooves to the substrate surface is fixed to the movable side mold 1.

【０００８】他方、固定側金型２の中央に湯口筒体即ち
スプルー部５が設けられている。このスプルー部５は溶
融樹脂流路が形成されており、その一端は金型１，２間
に形成されるキャビティー３内に開口し、且つ、他端は
射出ノズル（図示せず）に接続している。本発明の光デ
ィスク用基板成形法はこのような成形装置によって実施
される。図１において、可動側金型１と固定側金型２が
型閉され、例えばポリカーボネートの様な溶融樹脂が射
出ノズルからスプルー部５を介してキャビティー３内に
充填される。溶融樹脂のキャビティー３への射出開始前
〜終了後のどこかのタイミングで金型は加圧される。On the other hand, a sprue portion 5, that is, a sprue portion 5, is provided at the center of the stationary die 2. The sprue portion 5 has a molten resin flow path formed therein, one end of which opens into the cavity 3 formed between the molds 1 and 2, and the other end of which is connected to an injection nozzle (not shown). are doing. The optical disk substrate molding method of the present invention is carried out by such a molding apparatus. In FIG. 1, the movable side mold 1 and the fixed side mold 2 are closed, and a molten resin such as polycarbonate is filled into the cavity 3 from the injection nozzle through the sprue portion 5. The mold is pressurized at some timing before the start of injection of the molten resin into the cavity 3 and after the end.

【０００９】この金型への型締め最大圧力は通常４０〜
６００剤〔ｋｇｆ／ｃｍ2 〕程度で、望ましくは５０〜
４００〔ｋｇｆ／ｃｍ2 〕の範囲である。この型締めの
射出圧縮圧力によりキャビティー３内の溶融樹脂は所望
の板厚ディスクに圧縮され、、スタンパー４のピットま
たは溝等のプリフォーマット情報が転写される。そし
て、プレス成形後はこの型締め圧力をそのまま保持、或
いは段階的に変化させる。この後、成形されたディスク
基板を金型１，２から取り出す。すなわち、金型を開く
直前に固定金型２に付属したエアー離型機構から基板と
固定金型２との間にエアーを導入してディスク基板を固
定金型２から引き離し金型を開く。The maximum mold clamping pressure on this mold is usually 40-
About 600 agents [kgf / cm 2 ], preferably 50-
It is in the range of 400 [kgf / cm 2 ]. The molten resin in the cavity 3 is compressed into a disk having a desired plate thickness by the injection compression pressure of this mold clamping, and preformat information such as pits or grooves of the stamper 4 is transferred. After the press molding, the mold clamping pressure is maintained as it is or is changed stepwise. After that, the molded disk substrate is taken out from the molds 1 and 2. That is, immediately before opening the mold, air is introduced between the substrate and the fixed mold 2 from the air release mechanism attached to the fixed mold 2 to separate the disk substrate from the fixed mold 2 and open the mold.

【００１０】可動金型１側は、金型を開くと同時、ある
いは、型開後に機械的突出機構が動作するまでの間にエ
アー供給することにより、ディスク基板をスタンパー４
から引き離す。本発明においては、キャビティー内に溶
融樹脂を導入（充填）後、キャビティー内の樹脂を冷却
するに当たり、可動金型１と固定金型２との開き量（キ
ャビティーの開き量）を制御して冷却する点にある。On the movable mold 1 side, air is supplied at the same time as the mold is opened or until the mechanical projection mechanism operates after the mold is opened, so that the disk substrate is stamped by the stamper 4.
Pull away from. In the present invention, after the molten resin is introduced (filled) into the cavity, when the resin inside the cavity is cooled, the opening amount between the movable mold 1 and the fixed mold 2 (the opening amount of the cavity) is controlled. Then it is in the point of cooling.

【００１１】キャビティーの開き量は、例えば一定の圧
力を可動金型に加えておけば、キャビティー内の樹脂が
冷却され、収縮するにつれ変化する。しかしこの方法で
は、得られる光ディスク基板の複屈折が基板によって大
きく変わる（バラツク）という問題がある。本発明で
は、キャビティーの開き量を金型の圧力を一定にして調
節するのではなく、経時的に予め設定された開き量とな
るように可動金型１の圧力を変化させる。The opening amount of the cavity changes as the resin in the cavity cools and contracts, for example, if a constant pressure is applied to the movable mold. However, this method has a problem that the birefringence of the obtained optical disk substrate greatly changes (varies) depending on the substrate. In the present invention, the opening amount of the cavity is not adjusted by keeping the pressure of the mold constant, but the pressure of the movable mold 1 is changed so that the opening amount becomes a preset opening amount with time.

【００１２】このようなキャビティーの開き量の制御を
行なうことにより基板間における複屈折のバラツキは極
めて小さくなる。キャビティーの開き量を経時的に設定
するのは、樹脂の冷却に併う収縮率等を考慮して何回か
の実験により得れば良い。このキャビティーの開き量の
制御はキャビティー内の樹脂の冷却時に行なわれるもの
であり、例えば溶融樹脂がキャビティーに導入射出さ
れ、この導入が終了した時点で何らかの信号（例えば、
射出ノズルのバルブ作動信号や、ゲートカット信号等）
を得、この信号を起点としてキャビティーの開き量を経
時的に制御すれば良い。By controlling the opening amount of the cavity as described above, the variation of birefringence between the substrates becomes extremely small. The amount of opening of the cavity may be set with time by taking several experiments in consideration of the shrinkage rate accompanying cooling of the resin. The control of the opening amount of the cavity is performed when the resin in the cavity is cooled. For example, a molten resin is introduced into the cavity and injected, and when this introduction is completed, some signal (for example,
(Injection nozzle valve operation signal, gate cut signal, etc.)
Then, the opening amount of the cavity may be controlled with time using this signal as a starting point.

【００１３】具体的な作動を図を用いて説明する。キャ
ビティーの開き量は図に示すように、例えば可動金型１
と固定側金型２との開き量（ｔ）を型開センサー６によ
って測定し、その測定信号を演算装置７に取り入れ、演
算装置７内に予め記憶されているキャビティーの開き量
設定値と対比し、その偏差を制御信号として演算装置７
から型締装置８に出力し、その制御信号に基づいて型締
装置８の型締め圧力を変え、所定のキャビティー開き量
に制御される。A specific operation will be described with reference to the drawings. As shown in the figure, the opening amount of the cavity is, for example, the movable mold 1
The opening amount (t) between the fixed side mold 2 and the fixed mold 2 is measured by the mold opening sensor 6, and the measurement signal is input to the arithmetic device 7, and the cavity opening amount set value stored in advance in the arithmetic device 7 In comparison, the deviation is used as a control signal for the arithmetic unit 7
Is output to the mold clamping device 8, the mold clamping pressure of the mold clamping device 8 is changed based on the control signal, and the cavity opening amount is controlled to a predetermined amount.

【００１４】時間的に説明すれば、キャビティー内に溶
融樹脂を充填後、０．１秒後から冷却工程終了まで、通
常は０．５秒後から１０秒後程度まで、少なくとも０．
５秒後から５秒後程度まで上記金型間の開き量を上記演
算装置７内に予め定められ所定の金型間の開き量の範囲
に制御して成形することにより、基板間の複屈折のバラ
ツキの小さな光ディスク用基板を得ることができる。Explaining in terms of time, after the molten resin is filled in the cavity, 0.1 seconds to the end of the cooling step, usually 0.5 seconds to 10 seconds, at least 0.
The birefringence between the substrates is controlled by controlling the opening amount between the molds within a range of a predetermined opening amount between the molds in the arithmetic unit 7 from after 5 seconds to after about 5 seconds. It is possible to obtain a substrate for an optical disc with a small variation.

【００１５】[0015]

【実施例】以下に実施例を示すが、本発明はその要旨を
越えない限り以下の実施例に限定されるものではない。 （複屈折の測定法）基板の複屈折は、Ｈｅ−Ｎｅレーザ
波長６３３ｎｍを光源とした直線偏光を基板に入射さ
せ、透過した光の楕円偏光状態を回転検光子により解析
することで測定した。また、複屈折値はレターデーショ
ン（シングルパス）で示した。EXAMPLES Examples will be shown below, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. (Measurement Method of Birefringence) The birefringence of the substrate was measured by making linearly polarized light having a He—Ne laser wavelength of 633 nm as a light source incident on the substrate and analyzing the elliptically polarized state of the transmitted light with a rotation analyzer. The birefringence value is shown by retardation (single pass).

【００１６】実施例１ 図に概略を示す成形装置を用い、可動側金型１にスタン
パー４を取り付け、金型１，２を型閉し、金型間の開き
量（キャビティー開き量）を１．６ｍｍに調節した状態
で、成形機の射出シリンダー（３５０℃）よりスプルー
部５を経て分子量が１５０００のポリカーボネート溶融
樹脂材を金型温度１１０℃においてキャビティー３内に
充填した。型締め圧力をディスク面圧力で３００ｋｇ／
ｃｍ2 に加圧し、次いで上記溶融樹脂材充填後、１秒後
から４秒後までの間、金型間の開き量を図２に示す開き
量となるように型締め圧力を制御した。次いで、常圧に
戻し、金型とディスク基板との間にエアーを供給して、
これらを分離させた。Example 1 Using a molding apparatus schematically shown in the figure, a stamper 4 was attached to a movable side mold 1, the molds 1 and 2 were closed, and the opening amount between the molds (cavity opening amount) was measured. In a state of being adjusted to 1.6 mm, a polycarbonate molten resin material having a molecular weight of 15,000 was filled into the cavity 3 at a mold temperature of 110 ° C. from the injection cylinder (350 ° C.) of the molding machine through the sprue section 5. The mold clamping pressure is 300kg /
After pressurizing to 2 cm 2 and then filling the molten resin material, the mold clamping pressure was controlled from 1 second to 4 seconds so that the opening amount between the molds would be the opening amount shown in FIG. Then, return to normal pressure, supply air between the mold and the disk substrate,
These were separated.

【００１７】得られたディスク基板（直径１３０ｍｍ、
板厚１．２ｍｍ）１００枚はスタンパーの溝、ピットの
転写性は良好であり、複屈折は半径方向３０ｍｍの位置
で最大−１２ｎｍ、最小−８ｎｍであり、そのバラツキ
は−４ｎｍであり、また半径方向６０ｍｍの位置で最大
１５ｎｍ、最小１０ｎｍであり、そのバラツキは５ｎｍ
であった。The obtained disk substrate (diameter 130 mm,
100 sheets (thickness: 1.2 mm) have good transferability of the grooves and pits of the stamper, the maximum birefringence is -12 nm and the minimum is -8 nm at a position of 30 mm in the radial direction. The maximum is 15 nm and the minimum is 10 nm at the position of 60 mm in the radial direction, and the variation is 5 nm.
Met.

【００１８】比較例１ 実施例１において、溶融樹脂充填終了後の金型間の開き
量を実施例１のように調節せず、型締め圧力をディスク
面圧力で３００ｋｇ／ｃｍ2 で冷却終了まで加圧保持し
た。その際の金型間の開き量を測定した結果を図３に示
した。冷却開始後型開き量に変動のあることがわかる。
複屈折は変形方向３０ｎｍの位置で最大−１５ｎｍ、最
小−５ｎｍであり、そのバラツキは−１０ｎｍであっ
た。また半径方向６０ｍｍの位置で最大２２ｎｍ、最小
−５ｎｍであり、そのバラツキは２７ｎｍであった。Comparative Example 1 In Example 1, the opening amount between the molds after the completion of the molten resin filling was not adjusted as in Example 1, and the mold clamping pressure was 300 kg / cm 2 as the disc surface pressure until the end of cooling. It was held under pressure. The result of measuring the opening amount between the molds at that time is shown in FIG. It can be seen that the mold opening amount varies after the start of cooling.
The birefringence was -15 nm at the maximum and -5 nm at the minimum in the deformation direction of 30 nm, and the variation was -10 nm. The maximum at the position of 60 mm in the radial direction was 22 nm, the minimum was -5 nm, and the variation was 27 nm.

【発明の効果】本発明の方法によれば、基板成形時にお
ける基板間の複屈折のバラツキの小さい光ディスク用基
板が得られる。According to the method of the present invention, it is possible to obtain a substrate for an optical disk in which birefringence variation between the substrates at the time of molding the substrate is small.

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

【図１】 本発明の方法に用いられる装置の一例の説明
図FIG. 1 is an explanatory view of an example of an apparatus used in the method of the present invention.

【図２】 実施例１の型開き量のグラフFIG. 2 is a graph of the mold opening amount of Example 1.

【図３】 比較例１の型開き量のグラフFIG. 3 is a graph of the mold opening amount of Comparative Example 1.

【符号の説明】[Explanation of symbols]

１ 可動側金型 ２ 固定側金型 ３ キャビティー ４ スタンパー ５ スプルー部 ６ 型開センサー ７ 演算装置 ８ 型締装置 1 Mold on movable side 2 Mold on fixed side 3 Cavity 4 Stamper 5 Sprue part 6 Mold opening sensor 7 Computing device 8 Mold clamping device

Claims (3)

【特許請求の範囲】[Claims] 【請求項１】 金型のキャビティー内にプリフォーマッ
ト情報を有するスタンパーを取り付け、キャビティー内
に溶融樹脂を導入してプリフォーマット情報が転写され
た光ディスク用基板を成形する方法において、キャビテ
ィー内の樹脂を冷却する際にキャビティーの開き量を変
化させつつ冷却を行ない、キャビティーの開き量は、溶
融樹脂の導入終了後、経過時間に応じ、予め設定された
開き量に制御することを特徴とする光ディスク用基板の
成形方法。1. A method for forming a stamper having preformat information in a cavity of a mold and introducing a molten resin into the cavity to mold an optical disk substrate on which the preformat information is transferred. When cooling the resin, cooling is performed while changing the opening amount of the cavity, and the opening amount of the cavity can be controlled to a preset opening amount according to the elapsed time after the introduction of the molten resin is completed. A method for forming a substrate for an optical disc having a feature. 【請求項２】 溶融樹脂の導入終了の信号を得、該信号
を起点としてキャビティーの開き量を経時的に制御する
ことを特徴とする請求項１に記載の光ディスク用基板の
成形方法。2. The method for molding an optical disk substrate according to claim 1, wherein a signal of completion of introduction of the molten resin is obtained, and the opening amount of the cavity is controlled with time using the signal as a starting point. 【請求項３】 キャビティーの開き量を測定し、キャビ
ティーの開き量を設定値と比較し、その差に応じ金型の
型締め力を調節することによりキャビティーの開き量を
制御することを特徴とする請求項１又は２に記載の光デ
ィスク用基板の成形方法。3. The opening amount of the cavity is controlled by measuring the opening amount of the cavity, comparing the opening amount of the cavity with a set value, and adjusting the mold clamping force according to the difference. The method for molding a substrate for an optical disk according to claim 1 or 2.
JP17535994A 1994-07-27 1994-07-27 Molding of substrate for optical disk Pending JPH0839645A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP17535994A JPH0839645A (en) 1994-07-27 1994-07-27 Molding of substrate for optical disk

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP17535994A JPH0839645A (en) 1994-07-27 1994-07-27 Molding of substrate for optical disk

Publications (1)

Publication Number Publication Date
JPH0839645A true JPH0839645A (en) 1996-02-13

Family

ID=15994703

Family Applications (1)

Application Number Title Priority Date Filing Date
JP17535994A Pending JPH0839645A (en) 1994-07-27 1994-07-27 Molding of substrate for optical disk

Country Status (1)

Country Link
JP (1) JPH0839645A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109228177A (en) * 2018-10-12 2019-01-18 常州大学 The mechanism and method for preventing mould gate melt from flowing backwards

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109228177A (en) * 2018-10-12 2019-01-18 常州大学 The mechanism and method for preventing mould gate melt from flowing backwards

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