JP2002192578A - Mold apparatus for molding optical disk - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make stress hard to remain in the periphery of a ate at the time of cutting by a gate cutting sleeve and to increase the diameter of an ejector pin. SOLUTION: A flat land 37 is provided to the leading end of a gate cutting sleeve 29, and recessed pars 38 and 39 are formed to the leading end surface 9A of the projected part 9 of a sprue bush 6 is opposed relation to the land 37. The depth D' on the outer peripheral side of the recessed parts 38 and 39 is formed so as to become less than the depth E' on the center side of them. The diameter F of the opening part of an undercut 36 is formed so as to become 1/2 or more the diameter A of the gate cutting sleeve 29. By cutting a thinned place, the return of a resin at the time of cutting becomes smooth and stress becomes hard to remain in the periphery of a gate 34. The diameter of an ejector pin 30 can be made large.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, a CD (compact disk) and a DVD (digital video disk).
The present invention relates to a mold device for molding an optical disk such as an optical disk.

[0002]

The substrate of an optical disk is generally injection-molded with resin. In this molding, the fixed mold and the movable mold attached to the fixed plate and the movable plate of the injection molding machine are closed, a product cavity is formed between the fixed mold and the movable mold, and the product is injected from the nozzle of the injection molding machine. After filling the product cavity with the molten thermoplastic resin, which is the molding material obtained, and solidifying the resin in the product cavity, that is, the optical disk, in the mold adjusted to a predetermined low temperature, the fixed mold and the movable mold are opened. Then, the optical disk molded in such a manner is taken out.

As such a mold device for injection molding of an optical disk, Japanese Patent Laid-Open Publication No. Hei 8-156038 discloses a fixed mold and a movable mold provided opposite to the fixed mold. Forming a product cavity in the fixed mold, providing a sprue bush in the fixed mold, and providing a gate cut sleeve having an undercut portion in the center of the tip opposite to the sprue bush so as to be slidable in the movable mold. In the optical disk molding die apparatus provided with a flat land portion at the tip of the gate cut sleeve, the diameter of the undercut portion is set to １ ／ of the diameter of the gate cut sleeve.
A mold apparatus having a size of １ ／ is disclosed.

However, in such a conventional mold apparatus, the resin in the land portion has the same thickness on the center side and the outer peripheral side, so that the resin does not smoothly return at the time of cutting by the gate cut sleeve. There is a fear that stress tends to remain. Further, in the prior art, the diameter of the undercut portion is set to be 1/2 to 1/3 of the diameter of the gate cut sleeve, so that the diameter of the protruding pin penetrating the undercut portion may not be increased.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a mold apparatus for molding an optical disk, in which a stress hardly remains around the gate when the gate is cut by the gate cut sleeve and the diameter of the protrusion pin can be increased.

[0006]

According to a first aspect of the present invention, there is provided a fixed mold and a movable mold provided opposite to the fixed mold, wherein a product cavity is formed between the fixed mold and the movable mold. A sprue bush is provided in the mold, and a gate cut sleeve in which an undercut portion is formed in the center of the tip opposite to the sprue bush is slidably provided in the movable mold.
In the optical disk molding die device provided with a flat land at the tip of the gate cut sleeve, a recess is formed on the tip of the sprue bush in opposition to the land, and the depth of the recess on the center side of the recess is formed. A mold apparatus for molding an optical disk, characterized in that the outer peripheral side is formed to have a smaller depth.

According to the configuration of the first aspect, the cutting force at the portion where the depth on the outer peripheral side is reduced can be reduced.

According to a second aspect of the present invention, a distance between an outer peripheral side of the concave portion and an outer peripheral side of the land portion is formed to be 0.3 mm or less,
2. An optical disk fixed die molding apparatus according to claim 1, wherein an outer periphery of said concave portion is provided so as to substantially face an outer periphery of said gate cut sleeve.

According to the configuration of the second aspect, the distance is formed to be 0.3 mm or less with respect to the depth on the outer peripheral side, so that the distance is reliably reduced.

According to a third aspect of the present invention, there is provided a fixed mold and a movable mold provided opposed thereto, a product cavity is formed between the fixed mold and the movable mold, and a sprue bush is provided in the fixed mold. A gate cut sleeve having an undercut portion through which a protruding pin passes through the center of the tip of the sprue bush is provided slidably on the movable mold, and a flat land portion is provided on the tip of the gate cut sleeve. The optical disk molding die device provided, wherein the diameter of the undercut portion is formed to be at least half the diameter of the gate cut sleeve portion.

According to the structure of the third aspect, the diameter through which the protrusion pin passes can be increased.

According to a fourth aspect of the present invention, the depth of the undercut portion is formed to be 1 mm or less, and the undercut angle of the undercut portion is formed to be 15 degrees or more. This is an optical disk molding die apparatus.

According to this configuration, the resin in the undercut portion can be cooled at an early stage, and the resin is locked on the outer periphery of the undercut portion.

[0014]

Embodiments of the present invention will be described below with reference to the accompanying drawings. In the figure, reference numeral 1 denotes a fixed mold, and 2 denotes a movable mold. The fixed mold 1 and the movable mold 2, which are molds, move in the vertical direction in the figure (mold opening and closing direction) to open and close, and form an optical disk when the mold is closed. Two product cavities 3 are formed between each other.

The fixed mold 1 has a fixed mold plate 4 as a base and a fixed side support as a base fixed to a surface (upper surface in the drawing) of the fixed mold plate 4 opposite to the movable mold 2. And a plate 5. In addition, the fixed-side receiving plate 5 includes:
A cold sprue bush 6 serving as a sprue bush is fixed to each of the product cavities 3.
The head 7 of the cold sprue bush 6 is fitted in a recess 8 formed in the fixed receiving plate 5, and has a cylindrical protrusion 9 on the fixed mold plate 4 side. Projection 9
Extends through the fixed-side mold plate 4 from the fixed-side receiving plate 5. A raw material supply nozzle 10 is provided on the head 7 of the cold sprue bush 6. Further, a raw material supply nozzle 10 of the head 7 is provided in the cold sprue bush 6.
A cold sprue 12 is formed as a material passage extending from the bottom surface to which is connected to the tip end surface of the protrusion 9. The cold sprue 12 communicates with the product cavity 3 and has a tapered shape whose diameter increases toward the product cavity 3. Reference numeral 13 denotes a recess formed in the head 7, into which the raw material supply nozzle 10 is inserted.

The fixed-side mold plate 4 includes the fixed-side receiving plate 5
And a cavity block 15 as a cavity forming member fitted inside the positioning frame 14. The cavity block 15 forms the product cavity 3. An annular outer stamper retainer 16 is detachably attached to the outer peripheral portion of the cavity block 15, and a cylindrical inner peripheral stamper retainer 17 is detachably attached to the inner peripheral portion. These stamper foots 16,
Numeral 17 is for holding a stamper 35 for forming a groove portion or a land portion of the optical disc in the cavity block 15 in a detachable manner. Further, the cavity block 15
An intermediate cylinder 18 is provided inside a cylindrical inner stamper holder 17
The projection 9 of the cold sprue bush 6 is fitted in the intermediate cylinder 18. The inner peripheral stamper holder 17 and the intermediate cylinder 18 form a part of the product cavity 3. Further, the cavity block 15
Inside, a temperature control passage 19 for passing a temperature control fluid such as cooling water is formed.

The movable mold 2 includes a movable mounting plate 20 mounted on a fixed platen of an injection molding machine, a movable receiving plate 21 fixed to a surface of the movable mounting plate 20 on the fixed mold 1 side. Fixed type 1 of this movable side receiving plate 21
And a movable mold plate 22 fixed to the side surface. The movable mold plate 22 includes a positioning frame 23 fixed to a surface of the movable mold receiving plate 21 on the fixed mold 1 side and a core block as a cavity forming member fitted inside the positioning frame 23.
It consists of 24. The core block 24 forms the product cavity 3. Also, the positioning frame 23
Are taperedly fitted to the positioning frame 14 of the fixed die 1. In the core block 24, a temperature control passage 25 for passing a temperature control fluid such as cooling water is formed.

Further, on the outer peripheral portion of the core block 24,
The butting ring 26 is fitted. The abutment ring 26 is used to hold the outer peripheral stamper presser on the fixed mold 1 side when the mold is closed.
16 to form the outer peripheral surface of the product cavity 3.

Further, a cylindrical air blowing / inserting member 27 is fixed to the inner peripheral portion of the core block 24 in a penetrating state, and a cylindrical protruding sleeve 28 is provided on the inner peripheral side of the air blowing / injecting member 27. Is fitted slidably in the mold opening and closing direction for a predetermined range, and a cylindrical gate cut sleeve 29 is fitted on the inner peripheral side of the protruding sleeve 28 so as to be slidable in the mold opening and closing direction for a predetermined range. A protruding pin 30 is fitted into the gate cut sleeve 29 so as to slide freely in a predetermined range in the mold opening and closing direction. The protruding sleeve 28 and the gate cut sleeve 29 are each urged to the opposite side of the fixed mold 1. Also, the gate cut sleeve 29 has a receiving portion that penetrates the movable-side mounting plate 20.
31 are protruding. When the receiving portion 31 is pressed by a pressing rod (not shown) provided in the injection molding machine, the gate cut sleeve 29 moves to the fixed mold 1 side. Also, the protruding pin 30
Is a protruding plate provided in the movable-side mounting plate 20.
Fixed to 32. When the protrusion plate 32 is pressed by another pressing rod (not shown) provided in the injection molding machine, the protrusion pin 30 moves to the fixed mold 1 side. Further, an interlocking pin (not shown) fixed to the protruding plate 32 has a protruding sleeve.
By pushing on 28, the protruding sleeve 28 moves to the fixed mold 1 side.

The gate cut sleeve 29 is removably fitted into the intermediate cylinder 18 of the fixed die 1 to form an opening at the center of the optical disk. Therefore, the protruding sleeve 28 and the air blow-out insert 27 located on the outer peripheral side of the gate cut sleeve 29 form a part of the product cavity 3. Further, between the outer peripheral portion of the distal end surface 9A of the projecting portion 9 of the cold sprue bush 6 on the fixed die 1 side and the outer peripheral portion of the distal end surface of the gate cut sleeve 29 on the movable die 2 side, the cold sprue 12 on the fixed die 1 side. Is formed to communicate with the product cavity 3.
Note that, in the figure, X indicates the central axis.

An undercut portion 36 is provided at the center of the tip of a gate cut sleeve 29 slidably provided on the core block 24 so as to face the sprue bush 6, and a gate cut sleeve is provided so as to surround the undercut portion 36. 29
A land portion 37 having a flat shape is formed in a ring shape at the front end portion. On the other hand, first and second concave portions 38 and 39 as first and second stages are formed concentrically at the center of the tip end surface 9A of the projecting portion 9 of the sprue bush 6 so as to face the land portion 37. , 39, the concave surface 38,
The depth D 'toward the cold sprue 12 side on the outer peripheral side is formed smaller than the depth E' toward the cold sprue 12 side on the center side of 39, and the outer peripheries of the concave portions 38 and 39 are formed on the outer perimeter of the gate cut sleeve 29. It is provided so as to be substantially opposed. That is, the distal end surface 9A of the projecting portion 9 of the cold sprue bush 6 communicates with the cold sprue 12 around the cold sprue 12 and is slightly larger than the diameter A of the gate cut sleeve 29 so as to substantially face the land portion 37. A first concave portion 38 having a diameter B and a shallow bottom and having a circular plane is formed. The outer periphery of the first recess 38 is formed perpendicular to the front end surface 9A. Further, the diameter B of the first recess 38 is between the first recess 38 and the cold sprue 12 side.
A shallow, flat, circular second surface with a slightly smaller diameter C
Are formed to communicate with each other. The outer periphery of the second concave portion 39 is formed to be inclined so as to gradually decrease in diameter toward the cold sprue 12 side. Therefore, the land portion 37 and the first concave portion
The distance E between the land 37 and the bottom 39A of the second concave portion 39 is longer than the distance D between the bottom 38A and the bottom 38A. That is, in the sprue land, the thickness (distance D) on the outer peripheral side is made smaller than the thickness (distance E) on the center side. Then, the thickness (distance E) on the center side of the disk shape is formed to be 0.6 mm or less, and the thickness (distance D) on the outer peripheral side is formed to be 0.3 mm or less.

Further, the diameter F of the opening of the undercut portion 36 is determined by the gate cut sleeve 29 and the land portion.
It is formed to be 1/2 or more of the diameter B of 37. Also, the depth G of the undercut portion 36 is formed to be 1 mm or less, and the undercut angle H, that is, the included angle between the perpendicular from the opening of the undercut portion 36 and the outer periphery of the undercut portion 36 is set to 1 mm.
It is formed at 5 degrees or more.

Next, a method for molding an optical disk using the above-described mold apparatus will be described. During molding, first, the fixed mold 1 and the movable mold 2 are closed, and two product cavities 3 are formed between the fixed mold 1 and the movable mold 2. With the mold closed in this way, the butting ring 26 of the movable mold 2
Abuts against the outer peripheral stamper retainer 16 of the fixed die 1, and the positioning frames 14 and 23 of the fixed die 1 and the movable die 2 are taperedly fitted to each other. Then, a molten thermoplastic resin as a thermoplastic molding material is injected from an injection molding machine. The resin is supplied from the nozzle 10 to the cold sprue 12, the first and second sprues.
And flows into the product cavity 3 from the gate 34 through the concave portions 38 and 39 in sequence. At this time, the thickness on the outer peripheral side is formed thinner in the vicinity of the land portion 37 than on the center side. The undercut portion 36 is also filled with a thermoplastic resin.

After the resin is filled into the product cavity 3, the receiving portion 31 of the gate cut sleeve 29 is pressed toward the fixed mold 1 by a pressing rod (not shown) provided on the injection molding machine side. As a result, the gate cut sleeve 29 moves to the fixed mold 1 side, and the intermediate cylinder 18 of the fixed mold 1 is moved.
In the first concave portion 38 in the inside. As a result, the resin in the cold sprue 12 and the resin in the product cavity 3, ie, the optical disk, are cut off on the side of the gate 34 that is formed thin (distance D).

After the resin in the product cavity 3 is cooled and solidified, the fixed mold 1 and the movable mold 2 are opened.
With this mold opening, the molded optical disk and the resin solidified in the cold sprue 12 first separate from the fixed mold 1. Then, when the ejection plate 32 is pushed toward the fixed mold 1 by a pressing rod (not shown) provided on the injection molding machine side, the ejection pin 30 is pushed together with the ejection plate 32.
Moves to the fixed mold 1 side, and ejects the solidified resin in the cold sprue 12 to release it from the movable mold 2. Further, the projecting sleeve 28 moves toward the fixed mold 1 in conjunction with the projecting plate 32, and projects the inner peripheral portion of the optical disk to be released from the movable mold 2. Then, the released optical disk is taken out by a take-out robot (not shown). Thereafter, the mold is closed again and the above molding cycle is repeated.

According to the structure of the above embodiment, a flat land portion 37 is provided at the distal end of the gate cut sleeve 29, and the concave portion 38 is formed on the distal end surface 9A of the projection 9 of the sprue bush 6 so as to face the land 37. , 39 and the recesses 38, 39
The gate cut sleeve 29 is actuated to make the resin in the cold sprue 12 and the resin in the product cavity 3, that is, the optical disk, closer to the gate 34 by forming the depth D ′ on the outer peripheral side smaller than the depth E ′ on the central side. When cutting is performed, the cut point can be made thinner, and as a result, the amount of runner that becomes resin to be discarded can be reduced.In addition, by cutting the thinned part, the resin can be returned smoothly during cutting. In addition, the stress hardly remains around the gate 34.

Further, the distance D between the outer periphery of the concave portions 38 and 39 and the outer periphery of the land portion 37, that is, the thickness of the outer periphery of the runner to be discarded is formed to be 0.3 mm or less. It is cooled at an early stage and the thickness can be reliably reduced. Further, since the outer periphery of the concave portion 38 is provided so as to substantially oppose the outer periphery of the gate cut sleeve 29, a portion at a distance D on the outer peripheral side, which has become thinner, can be reliably cut.

A flat land portion 37 is provided at the tip of a gate cut sleeve 29 having an undercut portion 36 formed at the center of the tip, and the diameter F of the opening of the undercut portion 36 is determined by the gate cut sleeve. The opening of the undercut portion 36 can be made large by forming the diameter of the undercut portion 36 at a half or more of the diameter A of 29, so that the diameter of the protruding pin 30 passing through the opening is set to, for example, 4 mm or more. As a result, the strength of the protruding pin 30 can be improved.

Further, the depth G of the undercut portion 36
Is formed to 1 mm or less, and the undercut angle H of the undercut 36 is formed to 15 degrees or more, so that the resin filled in the undercut 36 is cooled relatively early, and Engagement with resin can be secured.

The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention.

[0031]

According to the first aspect of the present invention, there is provided a fixed mold and a movable mold provided opposite to the fixed mold, wherein a product cavity is formed between the fixed mold and the movable mold, and the sprue bush is formed in the fixed mold. A gate cut sleeve having an undercut portion formed in the center of the tip thereof facing the sprue bush so as to be slidable in the movable mold, and a flat land portion is provided at the tip of the gate cut sleeve. In the provided optical disk molding die apparatus, a concave portion is formed on the distal end surface of the sprue bush in opposition to the land portion, and the depth of the outer peripheral side is made smaller than the depth of the concave side on the center side. This is a mold device for molding optical discs, which can reduce the amount of resin to be discarded and leave stress around the gate when cutting with the gate cut sleeve. Can Kukusuru.

According to a second aspect of the present invention, the distance between the outer peripheral side of the recess and the outer peripheral side of the land is formed to be 0.3 mm or less,
The optical disk fixed die molding apparatus according to claim 1, wherein an outer periphery of the concave portion is provided so as to substantially face an outer periphery of the gate cut sleeve, and the distance is set to 0.3 mm or less. The resin to be formed and discarded can be reliably reduced, and the stress around the gate can hardly remain.

According to a third aspect of the present invention, there is provided a fixed mold and a movable mold provided opposed thereto, a product cavity is formed between the fixed mold and the movable mold, and a sprue bush is provided in the fixed mold. A gate cut sleeve is provided slidably on the movable die, the gate cut sleeve having an undercut portion through which a protruding pin passes at the center of the tip facing the sprue bush, and a flat land portion is provided at the tip of the gate cut sleeve. The optical disc molding die device provided, wherein the diameter of the undercut portion is formed to be at least half the diameter of the gate cut sleeve portion, wherein the diameter of the protrusion pin is Can be increased to improve the strength.

According to a fourth aspect of the present invention, the undercut portion is formed to have a depth of 1 mm or less and the undercut angle of the undercut portion is formed to be 15 degrees or more. An optical disk molding die apparatus that quickly cools the resin in the undercut portion with a depth of 1 mm or less and controls the relationship between the undercut portion and the resin in the undercut portion during molding with an undercut angle of 15 degrees or more. Stopping force can be secured.

[Brief description of the drawings]

FIG. 1 is an overall sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view of a main part showing one embodiment of the present invention.

[Explanation of symbols]

 3 Product Cavity 6 Sprue Bush 9 Projection 9A Tip 15 Cavity Block (Mold) 24 Core Block (Mold) 29 Gate Cut Sleeve 30 Projection Pin 36 Undercut 37 Land 38 38 Depression D Distance D'E'G Depth A F Diameter H Undercut angle

Claims (4)

[Claims] 1. A fixed mold and a movable mold provided opposite to the fixed mold, wherein a product cavity is formed between the fixed mold and the movable mold, a sprue bush is provided in the fixed mold, and a sprue bush is provided in the sprue bush. An optical disc molding die having a gate cut sleeve having an undercut portion pierced at the center of the front end thereof slidably provided on the movable die, and a flat land portion provided at the front end of the gate cut sleeve. An apparatus for molding an optical disk, characterized in that a concave portion is formed on a tip end surface of a sprue bush in opposition to the land portion, and a depth on an outer peripheral side is smaller than a depth on a center side of the concave portion. Mold equipment. 2. The method according to claim 1, wherein a distance between an outer peripheral side of the concave portion and an outer peripheral side of the land portion is formed to be 0.3 mm or less, and an outer periphery of the concave portion is provided so as to substantially face an outer periphery of the gate cut sleeve. The mold device for molding a fixed optical disk according to claim 1. 3. A fixed mold and a movable mold provided opposite to the fixed mold, a product cavity is formed between the fixed mold and the movable mold, a sprue bush is provided in the fixed mold, and the sprue bush is provided in the sprue bush. An optical disc having a gate cut sleeve pierced with an undercut portion through which a protruding pin passes in the center of the distal end so as to be slidable in the movable die, and a flat land portion provided at the distal end of the gate cut sleeve; In the molding die apparatus, the diameter of the undercut portion is formed to be at least half the diameter of the gate cut sleeve portion. 4. The optical disk molding die according to claim 3, wherein the undercut portion has a depth of 1 mm or less and the undercut angle of the undercut portion is 15 degrees or more. apparatus.