JPH1119981A - Gate cutting method for plastic molded piece and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gate cutting device for a molded piece for use in cutting a gate portion of a plastic molded piece that can finish with a high accuracy a cut surface of a gate portion of even a plastic molded piece such as a fine lens and perform a cutting along the external configuration of the lens without a risk of a cut surface cutting into a lens main body. SOLUTION: A gate portion of a plastic lens 28 is cut straight at a pre-cutting portion 10. Thereafter, the pre-cut lens 28 is transferred to a finish cutting portion 11. At the finish cutting portion 11, the pre-cut surface is cut in an arc-like fashion along substantially the external configuration of the lens 28 while an end mill 39 is controlled to move in two axial directions X and Y. This enables a gate to be cut with a high accuracy along the external configuration of the lens 28 without a risk of cutting into a lens main body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of cutting a gate of a plastic molded product by separating a molded product by cutting a gate portion of the plastic molded product connected by a runner, and a gate cutting apparatus used for the method. Pickup devices such as compact disks and magneto-optical disks,
Plastic lenses used in compact cameras, etc.
The present invention relates to a gate cutting method and a device for a small formed product.

[0002]

2. Description of the Related Art In general, a plastic lens (hereinafter, referred to as a lens) 1 used in a pickup device or a compact camera of this type includes a cross-shaped or radial bar-shaped runner 2 as shown in FIG. Injection molding is performed with the tip connected. Then, after molding, the connecting portion between the lens 1 and the runner 2, that is, the gate portion 3 of injection molding is cut and separated into individual lenses 1.
Conventionally, as a method of cutting the gate section 3, there have been a method of cutting using a cutter or a grindstone, a method of cutting while applying heat using a hot nipper, and a method of cutting with a laser beam (for example, See JP-A-4-90319 and JP-A-8-150640.

[0003]

However, recently, in response to demands for downsizing of the pickup device in which the lens 1 is incorporated and speeding up of the feed speed, the lens 1 itself has been miniaturized in accordance with the demand. As a matter of course, the lens body 1a is reduced in size as described above.
Has become narrower. On the other hand, since the gate 3 connecting the lens 1 and the runner 2 serves as a gate during injection molding, even if the lens 1 is minimized, it is difficult to make it extremely small in accordance with it.
As shown in (1), the ratio of the width W of the gate portion 3 to the diameter of the lens 1 has become large.

In such a situation, in a conventional method of cutting the gate portion 3 using a cutter or a grindstone,
Since the gate portion 3 can be cut only with a simple straight line, there is a possibility that the blade of the cutter may cut into the lens body 1a when trying to cut the gate portion 3 neatly.
In the case of a very small lens 1 having a diameter of 3 mm or less, the vapor deposition atmosphere is disturbed at the cut portion of the gate portion 3, and the surface of the lens 1 cannot be uniformly coated, and the accuracy of the lens 1 cannot be improved. There was a possibility of affecting.

[0005] In addition, the method of cutting using a laser is disadvantageous due to thermal energy, for example, swelling due to thermal deformation of the cut surface occurs, the cut surface accuracy cannot be obtained, and it is necessary to cut the very small lens 1 with high accuracy. Not suitable for gate cut. Furthermore, in the method of cutting using a hot nipper, there is a possibility that the lens 1 is deformed by heat and the lens performance is changed. As described above, none of the conventional gate cutting methods is suitable for the gate cutting of the microlens 1, and the workability and the yield are poor.

Accordingly, the present invention provides a method for cutting a gate section of a plastic molded product with high precision even when the molded product is a plastic molded product such as a very small lens. Is to provide a gate cutting method for a molded product that can be cut in accordance with the external shape of the lens without biting into the lens body, and an apparatus used for the method.

[0007]

That is, in order to solve the above-mentioned problems, a feature of the gate cutting method according to the first aspect of the present invention is that a pre-cutting step of cutting a gate portion of a plastic molded product; A finish cutting step of cutting the precut surface of the gate portion along the substantially outer shape of the plastic molded product by controlling the axial movement.

A feature of a gate cutting method according to a second aspect of the present invention is that the gate portion is provided on a curved surface portion of a plastic molded product, and the finish cutting step is performed along a curved surface of the plastic molded product. Is to cut.

A feature of a gate cutting method according to a third aspect of the present invention is that a gate cutting method for a plastic molded product comprising a spherical lens body and a narrow peripheral flange formed around the lens body. A pre-cutting step of cutting the gate portion of the peripheral flange, and a finishing cutting step of cutting the pre-cut surface of the gate portion into an arc shape along the substantially outer shape of the peripheral flange of the plastic molded product by controlling the X and Y axes movement. Be prepared.

A feature of the gate cutting method according to a fourth aspect of the present invention resides in that in the finish cutting step, the plastic molded product is cut slightly inward from the outer peripheral line of the peripheral flange.

A feature of the gate cutting method according to a fifth aspect of the present invention is that, in the above-mentioned finishing cutting step, a notch portion for positioning is provided which cuts inward from an outline of a plastic molded product.

The gate cutting device according to claim 6 of the present invention is characterized in that a precut means for cutting a gate portion of a plastic molded product, a finish cutting means for cutting a precut surface of the gate portion, and the finish cutting. Means X, Y
Moving means for moving in two axial directions, and control means for controlling X and Y two-axis movement so that the finish cutting means moves along a substantially outer shape of the plastic molded article when cutting the precut surface. is there.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a gate cutting method and a gate cutting device according to the present invention will be described in detail with reference to the accompanying drawings. In this embodiment, a case where a very small plastic lens is used as a molded product will be described. FIG. 1 is a schematic diagram of a gate cutting device according to the present invention. In this figure, the gate cut device 7 is roughly divided into a work loading section 8, a positioning section 9, and a pre-cut section 1.
0, a finish cutting unit 11, a lens moving unit 12, and a lens unloading unit 13. The work is similar to the above-mentioned conventional example.
This is an injection molded product in which a lens is connected to each end of the runner.

The loading section 8 includes three clamp sections 14 arranged in parallel in the loading direction, a loading side moving block 15 to which the clamping sections 14 are fixed, and a rear side of the loading side moving block 15. Two loading-side Z-axis rails 16 that enable the moving block 15 to move up and down;
The loading side Y-axis rail 17 is fixed on the apparatus base 18 below the loading side Z-axis rail 16 so that the axis rail 16 can move in the Y-axis direction.

The clamp portion 14 has a grip 19 which can be opened and closed at the tip thereof, and can grip the vertical base 21 of the work 20. The carry-in side moving block 15 is slidable on the carry-in side Z-axis rail 16 by an air cylinder (not shown), and is movable up and down. The loading-side Z-axis rail 16 is configured to be movable in the Y-axis direction on the loading-side Y-axis rail 17 by an air cylinder (not shown). Therefore, the carry-in side moving block 15 can move in the vertical direction and the Y-axis direction.

In the carry-in section 8, the work 20 carried into the first holder 22a is moved to the first holder 22a after a certain time has passed.
a to the second holder 22b and the third holder 22c sequentially. This elapsed time depends on the cycle of the injection work and the work 2
0 is set in consideration of a cooling time to a temperature suitable for cutting, a subsequent cutting step, a time required for the cutting step, and the like. After the gate cut is completed, the runner is moved from the third holder 22c to the discharge chute 2 located thereunder.
3 to be discharged.

The positioning section 9 includes a positioning table 24 and a first parallel chuck 25 provided on the positioning table 24.
a and the second parallel chuck 25b. The first parallel chuck 25a is located at the pre-cut section 10, and the second parallel chuck 25b is located at the finish cutting section 11. Both the first parallel chuck 25a and the second parallel chuck 25b are, as shown in FIG. 2, a fixed chuck 26 fixed on a positioning table 24 and a fixed chuck 2
6 and a movable chuck 27 that moves in parallel on the positioning table 24 so as to face the same. The fixed chuck 26 and the movable chuck 27 are provided with a mortar-shaped lens holding portion 29 at the distal end, which is adapted to the outer shape of the lens 28. And
The lens 28 connected to the runner 30 is
When it is placed in the inside, the movable chuck 27 is closed by an air cylinder, and positioning can be performed by sandwiching the lens 28. At the same time as the work 20 is placed on the third holder 22c, the lens 28 is positioned on the lens holder 29 on the positioning table 24.

FIGS. 3 and 4 show the positioning of the lens 2.
8 shows a cutting method in the pre-cut portion 10 of FIG. The pre-cut unit 10 moves upward while rotating a cutter 31 such as a circular saw, and cuts the gate unit 33 linearly from below. At this time, the precut surface 32 of the gate portion 33 on the lens 28 side is set so as not to enter the inside of the lens outline 34 (indicated by a dashed line) including the peripheral flange 28b of the lens body 28a. Precut part 10
Is provided, the amount of cutting chips generated can be reduced as compared with the case where only the finish cutting portion 11 is provided, and in the case where only the finish cutting portion 11 is provided, the lens 28 rotates within the parallel chuck 25 due to the blade pressure. It is possible to prevent the possibility of misalignment. The pre-cut unit 10
Is generated by using a duct (not shown) and is prevented from adhering to the lens 28.

As shown in FIG. 1, the lens moving section 12 described above includes a lens moving block 35, and the lens moving block 35 is slid up and down.
A lens moving unit Z-axis rail 36 provided on the rear side,
The lens moving part Z-axis rail 36 is made up of a lens moving part X-axis rail 37 fixed to the device base 18 below the Z-axis rail 36 in order to slide in the X-axis direction. The lens moving block 35 has two air chucks 38 at the front end of the apparatus, and sucks and holds the lens 28 after the gate 33 is cut by the air chuck 38.
Since the lens moving block 35 is slidable in the vertical direction and the X-axis direction as described above, the first parallel chuck portion 25a, the second parallel chuck portion 25b, and the unloading portion 1
3, the lens 28 can be moved.

As shown in FIG. 1, the unloading section 13
An air chuck 48 having the same mechanism as the air chuck 38 of the lens moving section 12, an unloading section moving block 49 having a mechanism for moving the air chuck 48 in the vertical direction, and the unloading section moving block 49 being Y Feed screw 50 and unloading section Y for sliding in the axial direction
It comprises an axis rail 51 and an unloading section motor 52 for rotating the feed screw 50. The carry-out section moving block 49 can be moved on the alignment table 53 by the feed screw 50 and holds the lens 28 conveyed by the lens moving section 12 to the air chuck 4.
Aspirate at 8, and arrange on the alignment table at regular intervals. Then, the aligned lenses 28 are collected by a stocker (not shown).

FIGS. 5 and 6 show a processing method in the finish cutting section 11. In the finish cutting, the precut surface 32 of the precut lens 28 is
9 for cutting. When the end mill 39 chucked by the spindle rotates, the pre-cut surface 32 is cut by the outer peripheral edge of the end mill 39. By using the end mill 39, the diameter of the cutting blade can be reduced, and the precut surface 32 can be finished with high precision. Note that the cutting blade is not limited to the end mill 39, and a rotating tool such as a diamond tool may be used. The end mill 39 and the spindle are fixed on an X, Y two-axis table unit. The X and Y two-axis table units are obtained by mounting an X-axis table unit 43 on a Y-axis table unit 42. By rotating the X-axis motor 44 and the Y-axis motor 45, the feed screw 46 is rotated, and the end mill 39 and the spindle can be moved by a predetermined amount in the X and Y two-axis directions. As described above, by controlling the movement of the end mill 39 in the two axial directions, it is possible to perform the cutting finish according to the outline 34 of the lens 28 without leaving the peripheral flange 28b of the lens without biting into the lens body 28a. Note that chips generated in the finishing cutting section 11 are also sucked using a duct (not shown) and are prevented from adhering to the lens 28.

FIG. 7 shows a method of controlling the movement of the end mill 39. The end mill 39 first moves in the Y-axis direction from a stop position before machining, and advances to a cutting reference position. Then, the end mill is moved in the X-axis direction from the cutting reference position and slightly inside the outer shape of the lens 28 (at the same time), and at the same time, along the substantially outer shape of the lens 28 while simultaneously controlling the movement of the end mill in the X and Y two-axis directions. Then, the precut surface 32 is cut while moving while drawing a curve, and the cutting of the precut surface 32 is completed at the position. Further, after the movement in the X-axis direction (the position), the lens returns to the stop position, and the gate cutting step for one lens is completed. X and Y two-axis simultaneous control of the end mill 39
It is programmed in advance in the controller of the Y2-axis table unit 41, and is set to an optimum value according to the size of the lens, the position of the gate, and the like.

FIGS. 8 and 9 show the lens 28 after the gate has been cut in the finish cutting step as described above. As described above, by controlling the movement of the end mill 39 in the X and Y axes simultaneously, the gate can be cut along the substantially outer shape of the lens 28, and the lens body 2 can be cut.
It is possible to cut along the arc of the peripheral flange 28b without penetrating into 8a. In this case, as shown in FIG. 9, the end mill 3 is attached to the peripheral flange 28b of the lens 28.
It is also possible to cut the inside out of the outer shape line 34 by making the cut 9 slightly bite, and it is possible to provide a curved cut portion 47 on both sides of the cut portion for positioning. In general, since the lens body 28a is not formed into a complete spherical body, it is required that the lens body 28a be installed with a certain direction when incorporated in a pickup device or the like. In that case, by providing the above-described cut portion 47, it can be used for positioning the lens 28.

Next, all steps of the gate cutting method of the present invention will be described with reference to the flowchart of FIG. First, in the first step S1, the vertical substrate 2 of the work 20 immediately after the injection molding is carried out by a transport mechanism (not shown) on the side of the injection molding machine.
1 and the first holder 22 of the gate cutting device 7.
The work 20 is supplied onto the “a”. In the next step S2, the work 20 is sequentially moved to the second and third holders 22b and 22c, and cooled to a temperature suitable for cutting. After cooling, the work 20 is moved to the third holder 22c and transported to the pre-cut portion 10 (step S3), and then the lens 28 of the work 20 is gripped by the parallel chuck portion 25a of the positioning portion 9 to position the lens 28. (Step S4). In the pre-cut section 10, the gate section 33 of the positioned lens 28 is cut by a cutter at an appropriate position (Step S).
5). After the gate portion 33 is pre-cut, the parallel chuck portion 25a is removed, and the lens 28 is sucked by the air chuck 38 of the lens moving portion 12 instead.
(Step S6), where the parallel chuck portion 25b
And the positioning is performed (step S7). In the finish cutting section 11, the end mill 39 is controlled to move in the X and Y two-axis directions while the peripheral flange 28b of the lens 28 is
Along with cutting the pre-cut surface 32 in an arc shape,
Notch portions 47 for positioning are formed on both sides thereof (step S8). The lens 28 after the finish cutting is conveyed by the lens moving unit 12 to the lens discharge unit 13 (Step S).
9) After being aligned, it is stored in a stocker (step S1).
0).

As described above, the present invention is useful for the gate cut of an extremely small plastic lens mounted on a pickup device such as a compact disk or a magneto-optical disk. This technology can be widely applied to gate cutting of plastic molded products.

[0026]

As described above, according to the gate cutting method of the present invention, the pre-cutting step of cutting the gate portion of the plastic molded product, and the XY two-axis movement control, along the substantial outer shape of the plastic molded product, In order to include a finish cutting step of cutting the precut surface of the gate,
Even when the plastic molded product has a curved surface at the gate portion, the gate can be cut with high accuracy along the curved surface of the molded product.

According to the gate cutting method of the present invention, the plastic molded product is a small plastic lens composed of a spherical lens body and a narrow peripheral flange formed around the lens body. Even if there is, finish cutting in an arc shape along the approximate outer shape of the peripheral flange,
The gate can be cut with high precision according to the external shape of the lens without biting into the lens body.

Further, according to the gate cutting method of the present invention, since the positioning cutout portion is provided so as to bite inward from the outer shape line of the plastic molded product, when the plastic molded product has directivity, the cutout portion is provided. Positioning can be performed using the notch.

Further, according to the gate cutting device of the present invention, a precut means for cutting a gate portion of a plastic molded product, a finish cutting means for cutting a precut surface of the gate portion, and X, X A moving means for moving in the Y2 axis direction, and a control means for controlling the X and Y two-axis movement so that the finishing cutting means moves along the substantially outer shape of the plastic molded product when cutting the precut surface. Even when the plastic molded product is an extremely small pickup lens, the gate can be cut according to the external shape of the lens without damaging the lens body.

[Brief description of the drawings]

FIG. 1 is an overall view of a gate cutting device according to the present invention.

FIG. 2 is a perspective view showing a parallel chuck of a positioning unit of the gate cutting device according to the present invention.

FIG. 3 is a perspective view showing a cutting method in a pre-cut section.

FIG. 4 is a plan view showing a cutting method in a pre-cut section.

FIG. 5 is a perspective view showing a cutting method in a finish cutting section.

FIG. 6 is a plan view showing an X, Y two-axis moving mechanism of the end mill.

FIG. 7 is a plan view showing a movement control method of the end mill.

FIG. 8 is a perspective view showing the lens after finish cutting.

FIG. 9 is a plan view showing the lens after finish cutting.

FIG. 10 is a flowchart of a gate cutting method according to the present invention.

FIG. 11 is a plan view showing a gate cut of a conventional plastic molded product.

FIG. 12 is a plan view showing a conventional lens after cutting.

[Explanation of symbols]

 Reference Signs List 7 Gate cut device 10 Precut part 11 Finish cutting part 28 Plastic lens (plastic molded product) 28a Lens body 28b Peripheral flange 34 Outline line 41 X, Y two-axis movement control (X, Y two-axis movement means) 47 Cut part

Claims (6)

[Claims] 1. A pre-cutting step of cutting a gate portion of a plastic molded product, and a finishing cutting step of cutting a pre-cut surface of the gate portion along a substantially outer shape of the plastic molded product by controlling X and Y axes movement. A gate cutting method for a plastic molded product, characterized in that: 2. The plastic molded product according to claim 1, wherein the gate portion is provided on a curved surface portion of the plastic molded product, and the finish cutting step performs cutting along a curved surface of the plastic molded product. Gate cut method. 3. A method for cutting a gate of a plastic molded product comprising a spherical lens body and a narrow peripheral flange formed around the lens body, a precut step of cutting a gate portion of the peripheral flange, A finishing cutting step of cutting the precut surface of the gate portion in an arc shape along the substantially outer shape of the peripheral flange of the plastic molded product by the X and Y two-axis movement control. 4. The method of cutting a gate of a plastic molded product according to claim 3, wherein, in the finish cutting step, the plastic molded product is cut along a slightly inner side of an outline of a peripheral flange. 5. The gate of a plastic molded product according to claim 1, wherein in the finishing cutting step, a notch for positioning is provided which cuts into an inner side of an outline of the plastic molded product. Cutting method. 6. A precut means for cutting a gate portion of a plastic molded product, a finish cutting means for cutting a precut surface of said gate portion, and said finish cutting means being X, Y2.
A moving means for moving in the axial direction; and a control means for controlling X and Y two-axis movement so that the finish cutting means moves along a substantially outer shape of the plastic molded product when cutting the precut surface. Gate cut device for plastic molded products.