JP2008183688A - Sheet cutting method and sheet cutting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet cutting method capable of preventing the generation of a burr when cutting, and preventing the generation of minute chips. <P>SOLUTION: In the sheet cutting method for obtaining an annular sheet having a center hole from a sheet 3, a first knife 1 and a second knife 2 disposed so as to separate from a rotating shaft C by different distances are rotated, and the inner peripheral end and the outer peripheral end of the annular sheet are respectively simultaneously cut by the first knife 1 and the second knife 2. The first knife 1 and the second knife 2 are disposed so as to separate by the different distances in one direction from the rotating shaft C or in both directions from the rotating shaft C. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a sheet cutting method for cutting an annular sheet from a sheet and an apparatus for performing the method.

In recent years, the number of types of optical disks for recording typified by DVDs has increased, and the amount of demand has been increasing.
Further, as represented by the Blu-ray Disc, a recording capacity having a large capacity has been demanded.
In order to protect the recording surface of the Blu-ray recording optical disk, a disk-shaped sheet having a central hole (hereinafter referred to as “annular sheet” for convenience) is used.

An annular sheet is manufactured by cutting out from a sheet body having a certain area using a mold (see Patent Document 1).
As one example, FIG. 10 schematically shows a method for cutting an annular sheet using a shearing force.
In this method, as shown in the figure, an upper die X is disposed above and a lower die Y is opposed to the lower portion with a long sheet Z interposed therebetween.
The upper mold X includes a circular recess 100 having a diameter equal to the outer diameter of the annular sheet, and a through hole 101 having a diameter equal to the inner diameter (center hole diameter) of the annular sheet at the center of the recess 100. Yes.
The lower die Y has a convex portion 102 having an outer diameter equal to the inner diameter of the concave portion 100, and a core die 103 having a diameter equal to the inner diameter of the annular sheet is disposed at the center thereof so as to be movable up and down. ing.

When cutting the sheet into an annular shape, the upper mold X is first lowered toward the lower mold Y.
In this case, the concave portion 100 of the upper mold X and the convex portion 102 of the lower mold Y are fitted with a minute gap of, for example, 0.01 to 0.02 mm.
As a result, the sheet is sheared and cut to obtain a disk-shaped sheet having an outer diameter equal to the outer diameter of the annular sheet [see FIGS. 10 (a) and 10 (b)].

Next, as shown in FIG. 10C, the core die 103 of the lower die Y is raised toward the upper die X.
In this case, the core mold 103 is inserted into the through hole 101.
Then, the upper mold X is raised to the original position, and the lower mold Y core mold 103 is lowered to the original position.
Thereby, the center part of a disk shaped sheet | seat is cut off by shearing, and the disk shaped sheet | seat which has a center hole, ie, an annular | circular shaped sheet | seat, is obtained [refer FIG.10 (d)].

JP 2001-357561 A

However, burrs are likely to occur on the cut surface of the annular sheet cut by the shearing action of combining the two upper and lower molds as described above.
The burr generated on the cut surface of the annular sheet is also defined in the film thickness intermediate to the disk bonded when the annular sheet is bonded to the recording plate via the UV liquid in a later process. As well as causing variations in the thickness of the disc, it also causes variations in the thickness of the completed disc.
In addition, fine chips are likely to be generated during cutting, and the generated chips adhere to the annular sheet.
Since the annular sheet is directly attached to the recording layer of the optical disc, fine chips adhering to the surface of the annular sheet must be completely removed for quality maintenance.
For this reason, the annular sheet must be cleaned for a sufficient time, which increases the number of manufacturing steps.

Further, as another conventional method for cutting an annular sheet, there is a cutting method using a roll cut method.
In this method, an anvil roll which is an upper mold and a cutter roll which is a lower mold are used, and the blade edge of the cutter roll is pressed against the peripheral surface of the anvil roll with a constant force to push the sheet.
In this method, since the blade is pressed against the sheet from the vertical direction, a burr is generated on the cut surface.
In addition, there is a drawback that fine chips are generated during cutting.
In any case, the conventional methods described above are not satisfactory in terms of generation of burrs and chips on the cut end face.

The present invention has been developed to solve the above problems.
That is, an object of the present invention is to provide a sheet cutting method that can prevent generation of burrs during cutting and also prevent generation of fine chips.
Moreover, it aims at providing the cutting device.

  As a result of intensive research based on the background of the problems as described above, the present inventor adopts a method that does not use a mold, and separates the first knife disposed at different distances from the rotation axis and The present inventors have found that the above-mentioned problems can be solved by pressing the second knife against the sheet while rotating the second knife around the rotation axis, and the present invention has been completed based on the knowledge.

  That is, the present invention is (1) a sheet cutting method for obtaining an annular sheet having a center hole from a sheet, wherein the first knife and the second knife are arranged at different distances from the rotation axis. And a sheet cutting method in which the inner peripheral end of the annular sheet is simultaneously cut with a first knife and the outer peripheral end of the annular sheet is simultaneously cut with a second knife.

  Further, the present invention resides in (2) the sheet cutting method according to (1), wherein the first knife and the second knife are arranged at different distances from the rotation axis in one direction.

  Moreover, this invention exists in the sheet | seat cutting method as described in said (1) by which (1) and a 1st knife and a 2nd knife are arrange | positioned at different distances from a rotating shaft on both sides.

  Moreover, this invention exists in (4) and the sheet | seat cutting method as described in said (1) performed by pressing on a sheet | seat in the state which rotated each knife.

  Moreover, this invention exists in the sheet | seat cutting method as described in said (1) which rotates the said 1st knife or said 2nd knife with the rotational speed of 600-1000 rpm.

  The present invention also relates to (6) a sheet cutting device for obtaining an annular sheet having a central hole from a sheet, and a support base for holding the sheet, and a vertically movable mechanism disposed above the support base. A rotating arm, the rotating arm having a first knife and a second knife arranged at different distances from a rotation axis for rotating the rotating arm, In the sheet cutting apparatus, a first annular groove and a second annular groove for escaping the cutting edges of the knives and the second knife along the trajectory of the first knife and the second knife are formed.

  Further, the present invention resides in (7) the sheet cutting device according to (6), wherein the support base includes a pressing unit for holding the sheet by pressing.

  Moreover, this invention is (8) and the sheet cutting device as described in said (6) in which the said support stand has a suction means for hold | maintaining a sheet | seat by adsorption | suction.

  The present invention also resides in (9) the sheet cutting apparatus according to (6), wherein the sheet is a long sheet, and the support is provided with sheet feeding means.

  Moreover, this invention exists in the sheet | seat cutting device as described in said (7) whose angle of the blade edge | tip of said (10) said 1st knife or said 2nd knife is 25 degrees-35 degrees.

  In addition, as long as the objective of this invention is met, the structure which combined said (1) to (10) suitably is also employable.

Since the shearing force is not used on the cut surface of the annular sheet manufactured by the sheet cutting method of the present invention, no burrs are generated.
Further, when the sheet is cut using the sheet cutting method of the present invention, fine chips are not generated.
Therefore, the disc quality when the annular sheet cut on the disc is bonded is significantly improved.
Furthermore, it becomes unnecessary to perform the cleaning of the manufactured annular sheet over a sufficient period of time, the number of manufacturing steps is reduced, and as a result, the manufacturing line can be simplified and the manufacturing time can be shortened.

[First embodiment]
An embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is an explanatory diagram schematically showing the arrangement relationship of knives in the sheet cutting method of the present embodiment.
As shown in FIG. 1, a vertically rising axis is defined as a rotation axis C at an arbitrary position on the sheet 3 (specifically, held on a support base as will be described later). A first knife 1 and a second knife 2 are arranged.
The first knife 1 and the second knife 2 are in a straight line on one direction side of the rotation axis C, and are arranged at different distances.

At this time, the first knife 1 is disposed at a distance position away from the rotation axis C by the same length D1 as the inner diameter (that is, the center hole diameter) of the annular sheet, and the second knife 2 is disposed at the rotation axis. It is arranged at a distance position away from C by the same length D2 as the outer diameter of the annular sheet.
The cutting edges of the first knife 1 and the second knife 2 are preferably arranged on a plane parallel to the sheet 3 as shown in FIG.

The rotation axis C serves as a rotation axis when the first knife 1 and the second knife 2 are rotationally moved on a certain circular orbit.
Therefore, the first knife 1 rotates about the rotation axis C to draw a circular orbit with a radius D1, and the second knife 2 also rotates about the rotation axis C to draw a circular orbit with a radius D2. .

As the arrangement method of the first knife 1 and the second knife 2, it is also possible to employ a method of arranging the first knife 1 and the second knife 2 on the opposite sides via the rotation axis C, for example.
That is, as shown in FIG. 2, the first knife 1 and the second knife 2 are arranged on a straight line at different distances on both sides of the rotation axis C.

  Incidentally, even in the case of FIG. 1, it is not always necessary to arrange the rotation axis C, the first knife 1 and the second knife 2 in a straight line. As shown in FIG. It is also possible to arrange the first knife 1 and the second knife 2 so that the line connecting the knife 1 and the line connecting the rotation axis C and the second knife 2 have a constant angle θ. is there.

  Similarly, in the case of FIG. 2, the rotation axis C, the first knife 1 and the second knife 2 do not necessarily need to be arranged in a straight line, and as shown in FIG. It is also possible to arrange the first knife 1 and the second knife 2 so that the straight line connecting the first knife 1 and the straight line connecting the rotation axis C and the second knife 2 have a constant angle θ. It is.

Here, the material of the sheet 3 to be cut according to the present invention is not particularly limited, but it is preferable to use polycarbonate as the protective sheet of the optical disc for Blu-ray recording.
Also, the specification of the sheet 3 is not particularly limited. For example, when an annular sheet is used for manufacturing a Blu-ray Disc (registered trademark), the outer diameter is generally 119.5 mm and the inner diameter (center). The hole diameter is 23 mm, and the thickness is 0.09 mm.

When cutting with such a knife, as shown in the state of being cut in FIG. 4, each knife is rotated on a circular orbit about the rotation axis C, and the first knife is kept rotated. The first and second knives 2 are pressed against the sheet 3 and pushed.
As a result, the sheet 3 is cut, and an annular sheet (that is, a donut-shaped sheet) having a central hole formed at a time is obtained.

  The sheet cutting method of the present embodiment is not cut by applying a shearing force or a pressing force perpendicular to the surface of the sheet as in the prior art, but with the blade inserted into the sheet. Then, the sheet is moved to cut the sheet (cut by a so-called pulling action).

  That is, the conventional sheet cutting method cuts the sheet by a shearing force or a pressing force in a direction perpendicular to the surface of the sheet, whereas the sheet cutting method of the present embodiment is performed on the sheet. Since the sheet is cut by the pulling force in the parallel direction, it is difficult to apply excessive stress to the sheet.

  Therefore, when the sheet is cut using the sheet cutting method of the present embodiment, burrs, chips, and the like are not generated on the cut surface as in the conventional sheet cutting method.

In the sheet cutting method of the present invention, the knife is pressed against the sheet in a rotated state, that is, the sheet is cut while the knife is initially inserted into the sheet. The cut surface becomes more uniform than when rotated.
Since the blade moves while being inserted, the impact of attachment does not concentrate on one point, and the cut surface becomes uniform in the circumferential direction.

  At this time, the rotational speed of the knife is preferably in the range of 600 to 1000 rpm from the viewpoint of the uniformity of the cut surface.

  Next, an example of a sheet cutting apparatus for performing the sheet cutting method of the present embodiment will be described.

5 and 6 are explanatory views schematically showing the sheet cutting device, in which FIG. 5 is a side view and FIG. 6 is an overall side view.
As shown in the figure, the sheet cutting apparatus A includes a support base 10 for holding a sheet horizontally and a rotary arm 13 disposed above the support base 10 and capable of rotating and lifting. Is provided.
In addition, although the support base 10 is equipped with the drive means, the concrete structure is abbreviate | omitted.
Further, drive sources (motors and the like) M1 and M2 for rotating and raising and lowering the rotary arm 13 are provided.

A rotating arm 13 is attached to the rotating shaft 11, and the rotating arm 13 rotates around the rotating shaft 11.
The first knife 1 is vertically mounted on the rotary arm 13 at a distance position away from the rotary shaft 11 by the same length as the inner diameter of the annular sheet.
Similarly, the second knife 2 is mounted on the rotary arm 13 at a distance position away from the rotary shaft 11 by the same length as the outer diameter of the annular sheet.

Here, as shown in FIG. 7, the angle θ of the cutting edges of the first knife 1 and the second knife 2 is preferably 25 ° to 35 °.
When the angle θ of the blade edge is in the range of 25 ° to 35 °, the stability at the time of cutting is high, and the state of the sheet cross section becomes extremely uniform.

A first annular groove 14 is formed in the support base 10.
The first annular groove 14 is an annular groove formed along the rotation trajectory of the first knife 1 and escapes the blade edge of the first knife 1 downward.

  Further, the support base 10 is formed with a second annular groove 15, and this second annular groove 15 is also an annular groove formed along the rotation path of the second knife 2, and the first annular groove 15. 14 has the same function.

On the other hand, the support base 10 is provided with a presser 16 that is a pressing means for preventing the position of the sheet 3 from moving during cutting.
The presser 16 is provided outside the second annular groove 15, has a driving means (not shown), and presses the movable sheet 3 from above to sandwich the sheet 3 with the support 10. This prevents the sheet 3 from moving.

It is preferable that a plurality of the pressing tools 16 are provided at circumferential positions.
By providing a plurality of pressers 16 in a circumferential shape, during the cutting of the sheet 3, the holding force is exerted against the force in all directions applied to the sheet 3, and the position of the sheet 3 is securely fixed. be able to.

Further, it is preferable to provide suction holes 17 as suction means for holding the sheet 3 in the support base 10.
By providing the suction hole 17, it is possible to prevent the displacement of the sheet 3 more reliably.
Since suction by the suction holes 17 does not damage the sheet, the suction hole 17 is used to correspond to the region corresponding to the annular sheet.
Moreover, the sheet | seat 3 respond | corresponds using the pressing tool 16 to areas other than the part which contributes to an annular | circular shaped sheet | seat.
By adopting both the pressing means and the suction means, it is possible to reliably prevent displacement of the sheet 3 in all directions during cutting with a knife.

When the sheet 3 is cut by such a cutting device, the sheet 3 is first automatically sent onto the support 10.
When feeding at a constant pitch is completed, the presser 16 is lowered and the sheet 3 is pressed.
At the same time, a suction source (not shown) is activated, the suction hole 17 becomes negative pressure, and the sheet 3 is sucked.
Next, the rotary arm 13 equipped with a knife descends while rotating and pierces the sheet 3.
It is preferable that the descending speed is fast until approaching the sheet 3 and moves slowly after approaching the sheet 3.
As described above, the annular sheet is cut out by the rotational movement of the knife.
As soon as the cutting is completed, the rotary arm 13 is raised to the original position.
Meanwhile, the annular sheet is quickly taken out by an unillustrated unloading tool.
Thereafter, the sheet 3 is pitch-fed again, and the following operations are repeated.
Here, instead of taking out the annular sheet with the carry-out tool, it is also possible to retract the support base 10 and bring another stand-by support base into the cutting position.

(Other embodiments)
FIG. 8 shows another embodiment, and shows a side view schematically illustrating a cutting device used in the cutting method of FIG.
The first knife 1 and the second knife 2 are disposed on the opposite sides of each other via the rotation axis C, which is reasonable and efficient from the viewpoint of rotational inertia.

(Still another embodiment)
FIG. 9 is a front view for schematically explaining the sheet cutting apparatus provided with the chip removing means in the first embodiment.
In this sheet cutting apparatus, fine chips are likely to adhere to the knife, particularly the cutting edge, and it is preferable to remove this.
Here, a rotating hollow suction pipe 18 is employed as the chip removing means.
The suction pipe 18 is connected to a suction source (not shown) and can rotate around an axis B (shown by a chain line). (Turns along a plane perpendicular to the drawing sheet).

The suction pipe 18 is formed with a first suction port 18A and a second suction port 18B for sucking the first knife 1 and the second knife 2 at corresponding positions.
When the knife is in the standby state, the suction pipe 18 sucks the knife close to a distance of, for example, 2 to 3 mm, and removes chips adhering to the blade edge.
For reference, the suction pipe 18 is shown by a chain line in FIG.

In this case, chip dissipation can be prevented as much as possible by using suction force without adopting air blowing force.
After the chips are removed by suction, the suction pipe 18 rotates and quickly returns to a position where it does not get in the way.
As described above, since the hollow pipe 18 having the suction ports 18A and 18B corresponding to the knives 1 and 2 is adopted, the suction works reliably and the chips are easily removed from the knife located in the air. It can be done.

Although the present invention has been described above, the present invention is not limited to the embodiments, and various modifications can be made.
For example, in the sheet cutting apparatus A described above, when the sheet 3 is a long sheet wound, the annular sheet can be sequentially cut out and manufactured.
At this time, when the support base 10 is provided with feeding means for feeding the sheet 3 forward by a predetermined distance at predetermined time intervals, the annular sheet can be automatically and continuously manufactured.

FIG. 1 is an explanatory diagram for explaining the arrangement relationship of knives in the sheet cutting method according to the first embodiment. FIG. 2 is an explanatory diagram for explaining the arrangement relationship of knives in a sheet cutting method according to another embodiment. FIG. 3 is an explanatory diagram schematically showing an example of the arrangement of knives as viewed in a plan view. FIG. 4 is an explanatory diagram schematically showing a state in which the sheet is cut. FIG. 5 is a side view schematically illustrating an embodiment of the sheet cutting device. FIG. 6 is a side view schematically illustrating an embodiment of the sheet cutting device. FIG. 7 is a diagram for explaining the shape of the knife. FIG. 8 is a side view schematically illustrating another embodiment of the sheet cutting device. FIG. 9 is a front view schematically illustrating a sheet cutting device including a chip removing device. FIG. 10 is an explanatory view schematically showing a conventional sheet cutting method.

Explanation of symbols

A ... sheet cutting device B ... axis C ... rotary axis F ... plane L ... straight line X ... upper die Y ... lower die Z ... sheet 1 ... first knife 2 ... second knife 3 ... sheet 10 ... support 11 ... Rotating shaft 13 ... Rotating arm 14 ... First annular groove 15 ... Second annular groove 16 ... Presser 17 ... Suction hole 18 ... Suction pipe 18A ... First suction port 18B ... Second suction port 100 ... Recess 101 ... Through hole 102 ... Projection 103 ... Core type

Claims (10)

A sheet cutting method for obtaining an annular sheet having a central hole from a sheet,
The first knife and the second knife arranged at different distances from the rotation axis are rotated so that the inner edge of the annular sheet is rotated with the first knife, and the annular edge with the second knife. A sheet cutting method comprising cutting the outer peripheral ends of a sheet simultaneously.   The sheet cutting method according to claim 1, wherein the first knife and the second knife are arranged at different distances from the rotation axis in one direction.   The sheet cutting method according to claim 1, wherein the first knife and the second knife are arranged at different distances from the rotation axis in both directions.   The sheet cutting method according to claim 1, wherein the cutting is performed by pressing each knife against the sheet in a rotated state.   The sheet cutting method according to claim 1, wherein the first knife or the second knife is rotated at a rotation speed of 600 to 1000 rpm. A sheet cutting device for obtaining an annular sheet having a central hole from the sheet, and a support base for holding the sheet;
A rotating arm that can be moved up and down arranged above the support base,
The rotating arm has a first knife and a second knife arranged at different distances from a rotation axis for rotating the rotating arm;
A sheet cutting characterized in that a first annular groove and a second annular groove are formed on the support base to allow the cutting edges of the first knife and the second knife to escape along the trajectory of the first knife and the second knife. apparatus.   The sheet cutting device according to claim 6, wherein the support base includes a pressing unit for holding the sheet by pressing.   The sheet cutting apparatus according to claim 6, wherein the support base has suction means for holding the sheet by suction.   The sheet cutting apparatus according to claim 6, wherein the sheet is a long sheet, and the support base includes a sheet feeding unit.   The sheet cutting apparatus according to claim 7, wherein an angle of a blade edge of the first knife or the second knife is 25 ° to 35 °.

Images