JP2000317996A - Gate cutter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cut a gate accurately in the extremely close vicinity to the surface of a product and to sufficiently smooth a cut surface. SOLUTION: A pair of cutters C1, C2 are heated to predetermined temp. in relation to the softening temp. of a synthetic resin constituting a gate to be cut and the edge parts C0, C0 thereof are arranged so as to be movable in opposed relationship and the cutter C1, C2 are mutually operated in such a state that the intermediate points of the edge parts C0, C0 are held to a constant position so as to synchronously approach each other in opposed relationship. The cross-sectional shape of a pair of the cutters C1, C2 is set to a mutually symmetric triangular shape and formed so that a pair of the sides opposed to a product are positioned on the same straight line.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gate cutter, and more particularly to a gate cutter that cuts a product near a surface of a product to separate the product into a gate and a product.

[0002]

2. Description of the Related Art Injection-molded products are usually molded to be connected to runners extending from sprues via gates. Therefore, in order to finally finish only the product, it is necessary to cut at the boundary between the gate and the product. In recent, so-called hot runner type molds, there are cases where the gate is molded to a very small one without the sprue or runner, but in the case of products requiring accuracy, the smoothness of the product surface is low. In the case of a required product, the product is often connected to a runner via the gate, and the runner is often connected to a sprue.

In such a case, in order to prevent the product from being distorted, it is necessary to make the gate sufficiently thick and set the injection pressure of the molten resin to the product portion high. As a method of cutting and separating such a product from the gate, there is a method of using a cutter in which a pair of blades cross in a V shape. This is a method of cutting the gate with a pair of so-called scissor blades. In this case, it is difficult for the cut end surface to be parallel to the product surface and to be smooth.

To solve this problem to some extent, there is a type in which a movable cutter contacts a fixed cutter in parallel. In this case, since the cutting is performed by a pair of cutters, the surface of the pair of cutters on the product side can be a plane parallel to the product surface, so that the above problem can be solved to some extent. Moreover, if the cutter is heated to a temperature near the softening point of the synthetic resin, the smoothness of the surface after cutting is improved.

However, even in this case, the smoothness cannot be said to be sufficient. Since one of the blades is fixed, when the gate is supported at the fixed position and the above cutting is performed, a pair of blades face and approach the gate having a generally circular cross section as shown in FIGS. Therefore, the midpoint position between the pair of cutters (C ₁ ) and (C ₂ ) changes as the cutting progresses. Therefore, the separating force of the pair of cutters (C ₁ ) and (C ₂ ) from the gate end surface (T) is different between the fixed side and the movable side of the cutters (C ₁ ) and (C ₂ ), and the movable side The repulsive force against the gate end surface (T) may become excessive, and the product may break (break) between the product and the gate before the end of cutting. In this case, the cut surface has sufficient smoothness. Does not.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has been made in consideration of the following problem: "This gate is cut by a pair of cutters (C ₁ ) and (C ₂ ) at the boundary between the product and the gate. The object of the present invention is to provide a gate cutter for separating a product by using a method capable of accurately cutting the product in the vicinity of the product surface and sufficiently smoothing the cut surface. * 1

[0007]

[MEANS FOR SOLVING THE PROBLEMS]
The solution of the present invention adopted in `` A pair of cutters (C₁) (C _Two)
Is the softening temperature of the synthetic resin that together constitutes the gate to be cut
Heated to a predetermined temperature in relation to the degree and its cutting edge
(C₀) (C₀) Are arranged to move in opposition, and the cutter
(C₁) (C_Two) Mutually, the cutting edge (C₀) (C₀The middle point of) is fixed
It is linked so that it comes and goes synchronously while maintaining the position,
A pair of the cutters (C₁) (C_Two) Are mutually symmetrical
With a triangular shape and facing the product side of this cross section
Are formed so that a pair of sides
It is that you are.

In the above means, when the gate extends vertically upward with respect to the product, the pair of sides located on the same straight line in the cross section are formed on the lower surface of the cutters (C ₁ ) and (C ₂ ). Correspondingly, this lower surface will face the product upper surface. The above solution works as follows. The product is positioned and fixed in relation to the gate cutters (C ₁ ) and (C ₂ ). Then, around the gate upstanding from the surface of the product, and the relationship that the pair of cutters (C ₁₎ (C ₂₎ is arranged opposite on both sides, one of said cutter (C ₁₎ (C ₂₎ Drive in the cutting direction.

Then, the cutting edge (C₀) (C₀The middle point of
These cutting edges (C₀) (C₀) Is on
Opposite approach is made synchronously by the link. Then, the gate
The cross section of the blade tip (C₀) (C₀) Symmetrically by
Being cut off. At this time, the product side surface of the cutter is
Facing the product surface, a pair of cutters (C₁) (C_Two) Of the above products
The opposite surfaces lie on one plane and the opposite surface is
Since the slope is in accordance with the triangular cross section,
The pair of gate end surfaces (T) and (T) are symmetric
(See FIG. 7). Moreover, the cutter (C ₁) (C_Two)
Is specified in relation to the softening temperature of the synthetic resin that constitutes the gate
The gate to its end, so to speak,
Cut while gradually melting from the edge of the surface. Therefore,
Excessive repulsion force as in the past is caused by the gate end face (T).
It has no effect on (T). And the cut surface on the product side is 1
The surface of the product is almost the same as the
The trace of the sheet becomes a smooth surface almost coincident with the product surface.

[0010]

According to the present invention having the above configuration, the following specific effects are obtained. While melting the gate while maintained at the gate center without an intermediate position of the cutting edge portion (C ₀₎ (C ₀₎ is moved, is cut by the cutting edge which moves symmetrically (C ₀₎ (C ₀₎ Therefore, the cut surface of the gate does not become a surface that is forcibly torn off.

Further, the cut surface on the product side is on the above-mentioned one plane.
Since it is almost the same, the gate trace remaining on the product is
If the product surface is flat, it should be almost flat
Face. [Others] * Claim 2 In the invention of Clause 1, "the blade edge (C₀) Is from the gate diameter
Is also long linear, the pair of linear cutting edges (C₀)
(C₀A support base that reciprocates in parallel with the middle line
(11) and this support base is moved by the linear motion mechanism (1).
The cutter (C₁) (C_Two)
And an interlocking mechanism (2) that moves them synchronously and symmetrically.
Provided on the support base (11), the blade tip (C₀) (C₀) On the intermediate line
The cutting edge (C) by the linear motion mechanism (1)₀) (C₀)
Product at a right angle to the upright position of the gate.
The jig (3) to be held is provided.)
The cutting edge (C₀) (C₀). In this state before
When the jig (3) holds the product in a predetermined posture, the cutting edge
(C₀) (C₀) And the gate are set to a predetermined relationship,
A pair of cutters (C₁) (C_Two) Moved
And the blade tip (C₀) (C ₀) Is the position across the gate, that is,
When set to the cutting position, the linear motion mechanism (1) moves.
Stop and move the cutter (C₁) (C_Two)
Tip (C₀) (C₀) Are facing each other and the cutting operation described above is performed.
Is performed.

As described above, according to the present invention, in addition to the above effects,
The product to the cutting edge (C₀) (C₀)
There is an advantage that an accurate gate cutting operation can be performed. * 3. In the above paragraph 2, “Products have gates with
The runners are connected to each other.
Molded as a product set extending from
Position the support position by supporting the runner from below
Temporary holding table (S_Three) Is a cutter supporting a gate cutter
On the table (D) '', one product is disconnected from the gate.
After cutting, when cutting the next product,
Stand (S _Three) And then a robot for the next cutting operation
It is easy to grab and change.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described.
This will be described together with the illustrated example. The gate cutter of this example is a gate cutter when a special prism (9) is formed by an injection molding machine. As shown in FIG. 2, each of the gates (92) connected to the runners (91) and (91) in the direction perpendicular to the runners from the vicinity of the tip of the runners (91) and (91) extending in four directions perpendicular to the sprue (90). A prism (9) as a product is formed at the tip of (). Then, these four prisms (9), gate (92), and runner (9)
As shown in FIG. 1, a pair of dies (K ₁ ) and (K ₂ ) corresponding to the configuration of a product set (94) comprising 1) are mounted on an injection molding machine (A).

[0014] The mold (K ₁₎ the the cavity side of the (K ₂₎ sprue (90) these mold in a manner to protrude (K ₁₎ (K ₂₎ is opened. The mold opening is a product take-out unit. As shown in FIG. 1, a take-out robot (L) is arranged in front of the take-out robot, and trays for product are stacked on the left and right of the take-out robot (L). Table (S ₁ ) and a transfer conveyor for sequentially transferring trays containing products to predetermined positions
(S ₂ ), and a temporary placing table (S ₃ ) of a product set (94) provided with four prisms (9) near the transfer conveyor (S ₂ ), and a jig (3). ) Is provided with a cutter base (D).

The details of the cutter table (D) will be described below. The gate cutter (G
C) has a configuration shown in FIGS. 3 to 6, in which a pair of rails (121) and (121) are provided in parallel on the upper surface of the support base (11), and the support base (1) is provided.
A linear drive (10) as a linear motion mechanism (1) is attached to a side plate (13) that stands upright from one end of 1), and a first linear bearing (12) provided on the rails (121) and (121) is mounted. The output shaft (101) of the linear driving machine (10) is mounted on an upright plate (29) which stands upright from a tool rest (20) supported so as to be able to reciprocate linearly through the same. A cutter (C ₁ ) (C ₂ ) and an interlocking mechanism (2) are attached to the tool rest (20), and the upright plate (29) is mounted on the upright plate (29).
The air cylinder (23) as a driving device of (2) and the linear motion speed controller (24) are attached.

[0016] Cutter _{(C 1) (C 2)} ] the cutter (C ₁₎ (C
₂₎ it is constructed in a plate shape, while the cutter (C ₁₎ is a tool rest
The cutter (C ₁ ) is supported by a second linear bearing (25) provided on the upper surface of (20) and arranged to move in a direction perpendicular to the rail (121).
It is connected to the output shaft of (23).

The other cutter (C ₂ ) is provided with the linear motion bearing (25).
Is supported by a third linear motion bearing (26) provided to move in parallel with the moving direction of the motor, and is connected to an output shaft of the linear motion speed controller (24). The one cutter (C ₁ ) is formed as a whole linear band-shaped plate body extending in the same direction as the second linear motion bearing (25), and has a blade tip ( C ₀ ) are formed. In addition, a heater (H) for heating the cutter (C ₁ ) is provided in the vicinity of the cutting edge (C ₀ ).

The other cutter (C ₂ ) is the third linear bearing
(26) It consists of a straight plate-like portion extending linearly along the bent portion and a bent plate-like portion bent at a right angle on the tip side thereof, and the tip of the one cutter (C ₁ ) is attached to the tip of the bent plate-shaped portion. The other edge (C ₀ ) is formed so as to face the edge (C ₀ ), and the edge (C ₀ ) is formed.
₀ ) (C ₀ ) are opposed to each other with a predetermined interval. The other cutter (C ₂ ) also has a heater near the cutting edge (C ₀ ).
(H) is provided.

The inner side of the _one cutter (C ₁ ) and the inner side of the linear plate portion of the other cutter (C ₂ )
As shown in FIGS. 3 and 5, the racks (22) and (22) are provided in parallel at a predetermined interval, and are provided on the inner side sides thereof.
Is engaged with the pinion (21). Therefore, when one of the cutters (C ₁ ) moves forward, the pinion (21) and the rack (22)
Due to the engagement of (22), the other cutter (C ₂ ) retreats. In other words, the cutting edge portions (C ₀ ) (C ₀ ) facing each other approach or approach or move away from each other.

[0020] In this example, cutting edges (C ₀₎ (C ₀₎ is opposed close by advancing operation of the output shaft of the air cylinder (23), the cutting edge portion by retraction of the output shaft (C ₀₎ (C ₀ ) Turns away. At this time, the operating speed is controlled to a predetermined speed by the linear motion speed controller (24). Therefore,
The instantaneous or impact operation by the air cylinder (23) is controlled, and is suitable for cutting by the cutting edge (C ₀ ) (C ₀ ) while being heated by the heater (H) (H). The speed of the cutters (C ₁ ) and (C ₂ ) is controlled according to the speed distribution.

[Temporary Placement Table (S ₃ ), Jig (3)] As shown in FIG. 1, the gate cutter (GC) is installed on the cutter table (D) together with the temporary place (S ₃ ). As shown in FIG. 2, the temporary placing table (S ₃ ) has a V-shaped groove (3) for supporting the runner (91) from below.
It consists of four support plates (38) (38) with 9). Since these V-shaped grooves (39) and (39) have been finished to a predetermined accuracy in advance, when the product set (94) is placed as shown in the figure, the sprue (90) is accurately upright. Become.

The sprue (9) is opened from the opening of the molds (K ₁ ) and (K ₂ ).
0) to be fitted to the holding portion (L _1), after removal of the product set (94) by removal robot (L), once placed on the product set (94) to the temporary support table (S ₃₎ I do. Then, after that, the prism (9) having the holding portion (L ₁ ) externally fitted to the sprue (90) again in a proper posture is set on the jig (3) in a proper posture.

As shown in FIG. 6, the jig (3) holds non-transmissive surfaces (95) (95) perpendicular to the light transmissive surface of the prism (9) and facing each other, or holds the non-transmissive surfaces (95). Horizontal non-transmissive surface (9
6) is a configuration having a horizontal surface that is in contact with, the prism, by the holding, and the contact with the horizontal surface,
(9) is accurately positioned. The holding position of the prism (9) by the jig (3) is appropriately set in advance, and as shown in FIGS. 1 and 3, the cutter (C) of the tool rest (20) at the initial position is used. ₁₎ (edge portion when C ₂₎ is open
It is located on the middle line (C ₃ ) of (C ₀ ) and (C ₀ ). That is,
The center of the gate (92) of the prism (9) in this holding state is located on the line of the intermediate line (C ₃ ). [Operation of each part] Before the gate cutting operation by the gate cutter (GC) is started, the heaters (H) and (H) are turned on, and the temperatures of the cutters (C ₁ ) and (C ₂ ) are raised to predetermined temperatures. You. This temperature is detected by a sensor (SC) provided on the bent plate portion of one of the L-shaped cutters (C ₂ ), and is maintained at the predetermined temperature by a temperature control device (not shown). Naturally, the predetermined temperature is set to a temperature suitable for cutting the gate (92) by the cutting edge (C ₀ ).

The robot (L) takes out the product set (94) from between the open dies (K ₁ ) and (K ₂ ) and temporarily places the cutter table (D) on the temporary table (S ₃ ). The above product set (9
4) is set to the proper posture. Then, again, the holding unit (L ₁ )
With the sprue (90) of the product set (94) re-gripped, the specific prism (9) to be cut is positioned at a predetermined position on the jig (3). Thereafter, the positioning mechanism (not shown) of the jig (3) is operated, and the gate (92) extending from the prism (9) set on the jig (3) and the gate (92) are arranged on the cutter table (D). Gate cutter (GC) cutter (C ₁ )
The relationship with (C ₂ ) is set to an appropriate relationship.

Thereafter, the linear driving machine (10) operates and its output shaft advances. Thereby, the initial position (the jig
The tool post (20), that is, the cutter (C ₁ ) (C ₂ ), which was set at a position where the cutting edge (C ₀ ) (C ₀ ) is a predetermined distance away from (3))
Moves along the intermediate line (C ₃ ) toward the prism (9) held by the jig (3). And the cutting edge (C ₀ ) (C ₀ )
When the line connecting the midpoints coincides with the center of the prism (9), the linear drive (10) is stopped, and in this state, the air cylinder (23) and the linear motion speed controller (24) operate. .

The cutting operation of the gate (92) by the cutting edge (C ₀ ) (C ₀ ) proceeds mainly by the output of the air cylinder (23). At this time, one of the cutters (C ₁ ) is advanced, but the other cutter (C ₂ ) is retracted via the interlocking mechanism (2), and its moving speed and moving distance are: Since they are set the same, the position of the intermediate line (C ₃ ) between the cutting edge portions (C ₀ ) (C ₀ ) does not change. It always coincides with the center of the gate (92).

In this state, the cutting operation of the gate (92) proceeds as shown in FIG. Therefore, the triangular cross section is
₀ ) moves symmetrically from both sides toward the stop of the gate (92) in the preceding mode, so that cutting failure unlike the conventional cutters (C ₁ ) and (C ₂ ) in which only one moves does not easily occur. In other words, the triangular cross section following one of the cutting edges (C ₀ ) is the gate (9
2) There is no inconvenience that the gate end surface (T) is cut off due to excessive penetration into the gate end surface (T).

Since each of the cutters (C ₁ ) and (C ₂ ) is heated to a predetermined temperature by the heater (H), the cutting edge (C ₀ ) advances to cut the gate (92). In addition, cutting is performed while being melted, and the cut surface becomes smoother from this point as well. Further, since the horizontal sides of the triangular cross section of each cutter are in the same straight line, the flat portion near the cutting edge (C ₀ ) is a flat surface on the upper surface of the prism (9) (the upright portion of the gate (92)). ), The gate 92 can be cut at a portion near the base.

[Others] In the above embodiment, the prism (9) has been described as an example of a product. However, as long as the product is formed at the tip of the gate (92), the product of various other shapes can be used. Can be used for gate cutting. Then, a jig (3) capable of holding the product according to its shape is prepared.

Also, the jigs (3) are respectively arranged as shown in FIG.
The pair of non-transmissive surfaces (95) and (95) are sandwiched between the fixed blocks (B) and (B), and the upper surface of the base block (B ₁ ) is
There is also a method of positioning by contacting (96),
The block (B) (B) by a clamp mechanism (not shown)
The pair of non-transmissive surfaces (95) and (95) may be clamped and positioned so as to be opposed to each other, and at this time, a surface opposite to the non-transmissive surface (96) is downwardly moved by a clamp device. The upper and lower positions may be determined by pressing the upper and lower surfaces.

[Brief description of the drawings]

FIG. 1 is a plan view of an installation mode of a gate cutter (GC) according to an embodiment of the present invention.

FIG. 2 is a detailed view of a temporary placing table (S ₃ ) in the cutter.

FIG. 3 is a detailed plan view of the gate cutter.

FIG. 4 is an overall side view.

FIG. 5 is a sectional view of an interlocking mechanism (2).

[Fig. 6] Holding of prism (9) by jig (3) and cutter
Side view showing the relationship with (C ₁ ) and (C ₂ )

FIG. 7 is a detailed view of the cutting operation by the cutting edge portion (C ₀ ) (C ₀ ).

FIG. 8 is a detailed view of a conventional cutting operation.

[Explanation of symbols]

(C ₁ ) (C ₂ ): cutter, (C ₀ ): blade edge, (T): gate end face, (1): linear motion mechanism, (11): support base, (12): first linear bearing , (13): side plate, (10): linear drive, (2): interlocking mechanism,
(20): Turret, (29): Upright plate, (23): Air cylinder,
(24): Linear motion speed controller, (25): Second linear bearing, (26): Third linear bearing (3): Jig, (39): V-shaped groove, (38): Support plate ,
(9): prism, (90): sprue, (91): runner, (9
2): Gate, (94): Product set, (95) (96): Non-permeable surface (S ₂ ): Transfer conveyor, (S ₁ ): Tray table, (S ₃ ): Temporary table, (L ₁₎ ): Holding part holding part, (L): Take-out robot, (G
C): Gate cutter, (K ₁ ) (K ₂ ): Mold, (A): Injection molding machine, (H): Heater,

Claims (3)

[Claims] 1. A pair of cutters at a boundary between a product and a gate.
In a gate cutter for cutting this gate by (C ₁ ) and (C ₂ ) to separate a product, a pair of cutters (C ₁ ) and (C ₂ )
Is heated to a predetermined temperature in relation to the softening temperature of the synthetic resin constituting the gate to be cut, and its cutting edge (C ₀ )
(C ₀ ) are arranged to move in opposition, and the cutter (C ₁ )
(C ₂ ) are interlocked with each other so that the intermediate point of the cutting edge portions (C ₀ ) and (C ₀ ) comes and goes synchronously while maintaining a fixed position, and a pair of the cutters (C ₁ ) (C ₂ ) A gate cutter in which the cross-sectional shape is set to a mutually symmetrical triangular shape and a pair of sides facing the product side of this cross-section are located on the same straight line. 2. The gate cutter according to claim 1, wherein the cutting edge (C ₀ ) has a linear shape longer than a gate diameter, and the pair of straight cutting edges (C ₀ ) (C ₀ ). ), A support table (11) reciprocating along the intermediate line is provided, and the support table is reciprocated by a linear motion mechanism (1), and the cutters (C ₁ ) and (C ₂ ) And an interlocking mechanism (2) for synchronously and symmetrically moving them is provided on the support (11), and the linear motion mechanism is provided on the intermediate line of the cutting edge (C ₀ ) (C ₀ ).
A jig for holding the product in a position perpendicular to the upright position of the gate in the movement range of the cutting edge portion (C ₀ ) (C ₀ ) according to (1).
Gate cutter with (3). 3. The gate cutter according to claim 2, wherein the product includes a gate having the gate connected to a runner, and the plurality of runners are molded as a product set extending from a sprue. Temporary holder (S) for supporting the runner from below and positioning the support position.
₃ ) A gate cutter provided on the cutter base (D) supporting the gate cutter.