Process and apparatus for injection-molding product having minute surface pattern and central hole

A process for injection molding of a disk substrate having a minute surface pattern and a central hole, comprising the steps of:

• injecting a resin into a cavity defined by a mold including a movable half provided with a stamper having a minute surface pattern and a fixed half defining the cavity in combination with the movable half to form a product;
• providing the movable half with an ejector ring reciprocally movable at first and second stage strokes in a mold opening-and-closing direction, a gate cutter reciprocally movable at first and second stage strokes in the mold opening-and-closing direction, and an ejector pin carried within the gate cutter and reciprocally movable in the mold opening-and-closing direction;
• moving the gate cutter at the first stage stroke to form a central hole of the product in the cavity and holding the product by a circumference of the gate cutter tip at its inner peripheral face of the central hole,
• opening the mold;
• substantially simultaneously with commencement of the mold opening, moving the ejector ring at the first stage stroke to release the product from the stamper and moving the gate cutter at the second stage stroke in a direction causing the release of the product from the stamper to retain the linkage between the gate cutter and the product, and
• after the mold is opened, moving the ejector ring to release a linkage between the gate cutter and the product and moving the ejector pin to release a sprue from the gate cutter.

A process for injection molding of a product having a minute surface pattern and a central hole, comprising the steps of:

• injecting a resin into a cavity defined by a mold including a movable half provided with a stamper having a minute surface pattern and a fixed half defining the cavity in combination with the movable half to form a product;
• providing the movable half with an ejector ring reciprocally movable at first and second stage strokes in the mold opening-and-closing direction and a gate cutter reciprocally movable at first and second stage strokes in the mold opening-and closing direction;
• moving the gate cutter at the first stage stroke to form a central hole of the product in the cavity, and holding the product by a circumference of the gate cutter tip at its inner peripheral face of the central hole,
• opening the mold;
• substantially simultaneously with commencement of the mold opening, moving the ejector ring at the first stage stroke to release the product from the stamper and moving the gate cutter at the second stage stroke in a direction causing the release of the product from the stamper to retain the linkage between the gate cutter and the product, and
• after the mold is opened, moving the ejector ring at a second stage stroke to release the linkage between the gate cutter and the product.

A process for injection molding of a disk substrate having a minute surface pattern and a central hole, comprising the steps of:

• injecting a resin into a cavity defined by a mold including a movable half provided with a stamper having a minute surface pattern and a fixed half defining the cavity in combination with the movable half to form a product;
• providing the movable half with an ejector ring reciprocally movable at first and second stage strokes in the mold opening-and-closing direction and a gate cutter reciprocally movable at first and second stage strokes in the mold opening-and-closing direction;
• moving the gate cutter at the first stage stroke to form a central hole of the product in the cavity, and holding the product by a circumference of the gate cutter tip at its peripheral face of the central hole;
• opening the mold;
• substantially simultaneously with commencement of the mold opening, moving the ejector ring at the first stage stroke to release the product from the stamper and moving the gate cutter at the second stage stroke in a direction causing the release of the product from the stamper to retain the linkage between the gate cutter and the product;
• and
• after the mold is opened, moving the ejector ring at the second stage stroke to release the linkage between the gate cutter and the product.

A process for injection molding of a product having a minute surface pattern and a central hole, comprising the steps of:

• injecting a resin into a cavity defined by a mold including a movable half provided with a stamper having a minute surface pattern and a fixed half defining the cavity in combination with the movable half to form a product;
• providing the movable half with an ejector ring reciprocally movable in a mold opening-and-closing direction, a gate cutter reciprocally movable at first and second stage strokes in the mold opening-and-closing direction, the movable half further including an outer periphery ring for affixing an outer periphery of the stamper to the movable half, the outer periphery ring having an inner surface defining a part of the cavity and having a tapered portion providing a diameter which gradually increases as it goes away from the stamper face, the fixed half being fitted against the outer periphery ring so as to define the cavity,
• moving the gate cutter at the first stage stroke to form a central hole of the product in the cavity;
• opening the mold;
• and
• substantially simultaneously with commencement of the mold opening, releasing the product from the stamper and moving the gate cutter at the second stage stroke in a direction causing the release of the product from the stamper, wherein
• the second stage stroke of the gate cutter has a length d.sub.4 sufficient to provide a spacing of at least 50 microns as a minimum distance between a data transfer face of the product and a face of the stamper, and
• the second stage stroke d.sub.4 of the gate cutter is set to a value in the range of D+X+(50/sin .theta.) to D+X+(300/sin .theta.), wherein D denotes the thickness of the cavity, X denotes the length over which the fixed half covers the inner face of the outer periphery ring at the time the mold is closed, and .theta. denotes the angle of taper of the outer periphery ring.

A process for injection molding of a product having a minute surface pattern and a central hole, comprising the steps of:

• injecting a resin into a cavity defined by a mold including a movable half provided with a stamper having a minute surface pattern and a fixed half defining the cavity in combination with the movable half to form a product;
• providing the movable half with an ejector ring reciprocally movable in a mold opening-and-closing direction, a gate cutter reciprocally movable at first and second stage strokes in the mold opening-and-closing direction, and an ejector pin carried within the gate cutter reciprocally movable in the mold opening-and-closing direction, the movable half further includes an outer periphery ring for affixing an outer periphery of the stamper to the movable half, the outer periphery ring having an inner surface defining a part of the cavity and having a tapered portion providing a diameter which gradually increases as it goes away from the stamper face, the fixed half being fitted against the outer periphery ring so as to define the cavity,
• moving the gate cutter at the first stage stroke to form a central hole of the product in the cavity, and holding the product by a circumference of the gate cutter tip at its inner peripheral face of the central hole,
• opening the mold;
• substantially simultaneously with commencement of the mold opening, releasing the product from the stamper and moving the gate cutter at the second stage stroke in a direction causing the release of the product from the stamper, wherein the second stage stroke of the gate cutter has a length d.sub.4, and the second stage stroke d.sub.4 is set to a value in the range of D+X+(50 .mu.m/sin .theta.) to D+X+(300 .mu.m/sin .theta.), wherein D denotes the thickness of the cavity, X denotes the length over which the fixed half covers the inner face of the outer periphery ring at the time the mold is closed, and .theta. denotes the angle of taper of the outer periphery ring, and
• after the mold is opened, moving the ejector ring to release a linkage between the gate cutter and the product, and moving the ejector pin to release a sprue from the gate cutter.

A process for injection molding of a product having a minute surface pattern and a central hole, comprising the steps of:

• injecting a resin into a cavity defined by a mold including a movable half provided with a stamper having a minute surface pattern and a fixed half defining the cavity in combination with the movable half to form a product;
• providing the movable half with an ejector ring reciprocally movable in a mold opening-and-closing direction, a gate cutter reciprocally movable at first and second stage strokes in the mold opening-and-closing direction, the movable half further includes an outer periphery ring for affixing an outer periphery of the stamper to the movable half, the outer periphery ring having an inner surface defining a part of the cavity and having a tapered portion providing a diameter which gradually increases as it goes away from the stamper face, the fixed half being fitted against the outer periphery ring so as to define the cavity;
• moving the gate cutter at the first stage stroke to form a central hole of the product in the cavity;
• opening the mold;
• and
• substantially simultaneously with commencement of the mold opening, releasing the product from the stamper and moving the gate cutter at the second stage stroke in a direction causing the release of the product from the stamper, wherein
• the second stage stroke of the gate cutter has a length d.sub.4, and
• the second stage stroke d.sub.4 is set to a value in the range of (D+X+(50 .mu.m/sin .theta.) to (D+X+(300 .mu.m/sin .theta.), wherein D denotes the thickness of the cavity, X denotes the length over which the fixed half covers the inner face of the outer periphery ring at the time the mold is closed, and .theta. denotes the angle of taper of the outer periphery ring.

An apparatus for injection molding of a product having a minute surface pattern and a central hole, comprising:

• a mold including a movable half provided with a stamper having a minute surface pattern and a fixed half forming a cavity to be filled with a resin in combination with said movable half, wherein
• said movable half is provided with an ejector ring reciprocally movable in first and second stage strokes in a mold opening-and-closing direction and a gate cutter reciprocally movable at first and second stage strokes in the mold opening-and-closing direction, and
• said movable half is further provided with means for causing the first stage stroke of said ejector ring to release the product from said stamper substantially simultaneously with commencement of the mold opening and means for causing a second stage stroke of said gate cutter in a direction causing the release of the product from said stamper substantially simultaneously with the mold opening, and
• the first stage stroke of said ejector ring is equal to or smaller than the second stage stroke of said gate cutter.

An apparatus for injection molding of a product having a minute surface pattern and a central hole, comprising:

• a mold including a movable half provided with a stamper having a minute surface pattern and a fixed half forming a cavity to be filled with a resin in combination with said movable half, wherein
• said movable half is provided with an ejector ring reciprocally movable in a mold opening-and-closing direction and a gate cutter reciprocally movable at first and second stage strokes in the mold opening-and-closing direction, and
• said movable half further includes an outer periphery ring for affixing an outer periphery of said stamper to said movable half, said outer periphery ring having an inner surface defining a part of the cavity and having a tapered portion providing a diameter which gradually increases as it goes away from a face of said stamper, said fixed half being fitted against said outer periphery ring so as to define the cavity,
• the second stage stroke of said gate cutter having a length d.sub.4 sufficient to provide a spacing of at least 50 microns as a minimum distance between a data transfer face of the product and said stamper face, and
• the second stage stroke d.sub.4 of said gate cutter being set to a value in the range of D+X+(50/sin .theta.) to D+X+(300/sin .theta.) wherein D denotes the thickness of the cavity, X denotes the length over which said fixed half covers said inner face of said outer periphery ring when the mold is closed, and .theta. denote the angle of taper of said outer periphery ring.

An apparatus for injection molding of a product having a minute surface pattern and a central hole, comprising:

• a mold including a movable half provided with a stamper having a minute surface pattern and a fixed half forming a cavity to be filled with a resin in combination with said movable half, wherein
• said movable half is provided with an ejector ring reciprocally movable in a mold opening-and-closing direction, a gate cutter reciprocally movable at first and second stage stroke sin the mold opening-and-closing direction, and an ejector pin carried within said gate cutter and reciprocally movable in the mold opening-and-closing direction to eject a sprue from said gate cutter, and
• said movable half further includes an outer periphery ring for affixing an outer periphery of said stamper to said movable half, said outer periphery ring having an inner surface defining a part of the cavity and having a tapered portion providing a diameter which gradually increases as it goes away from a face of said stamper, said fixed half being fitted against said outer periphery ring so as to define the cavity,
• the second stage stroke of said gate cutter having a length d.sub.4, and
• the second stage stroke d.sub.4 being set to a value in the range of D+X+(50 .mu.m/sin .theta.) to D+X+(300 .mu.m/sin .theta.), wherein D denotes the thickness of the cavity, X denotes the length over which said fixed half covers said inner face of said outer periphery ring when the mold is closed, and .theta. denotes the angle of taper of said outer periphery ring.

An apparatus for injection molding of a product having a minute surface pattern and a central hole, comprising:

• a mold including a movable half provided with a stamper having a minute surface pattern and a fixed half forming a cavity to be filled with a resin in combination with said movable half, wherein
• said movable half is provided with an ejector ring reciprocally movable in a mold opening-and-closing direction and a gate cutter reciprocally movable at first and second stage strokes in the mold opening-and-closing direction, and
• said movable half further includes an outer periphery ring for affixing an outer periphery of said stamper to said movable half, said outer periphery ring having an inner surface defining a part of the cavity and having a tapered portion providing a diameter which gradually increases as it goes away from a face of said stamper, said fixed half being fitted against said outer periphery ring so as to define the cavity,
• the second stage stroke of said gate cutter having a length d.sub.4, and
• the second stage stroke d.sub.4 of said gate cutter being set to a value in the range of D+X+(50 .mu.m/sin .theta.) to D+X+(300 .mu.m/sin .theta.), wherein D denotes the thickness of the cavity, X denotes the length over which said fixed half covers said inner face of said outer periphery ring when the mold is closed, and .differential.4 denote the angle of taper of said outer periphery ring.