Gate mark removal device and gate mark removal method

Abstract

Regardless of the gate's placement or shape, the goal is to remove gate marks at low cost by minimizing the amount of material left behind after cutting. [Solution] This gate mark removal device 10 comprises a holding part 23 capable of holding a resin molded product W, a gripping part 20 capable of gripping a gate mark Wg, a rotating gripping part 15 having a rotation drive unit 21 capable of rotating the gripping part 20 around a predetermined axis X, and a moving mechanism 16 capable of moving the rotating gripping part 15. The device is configured to hold the resin molded product W with the holding part 23 and grip the gate mark Wg with the gripping part 20, and then rotate the gripping part 20 with the rotation drive unit 21 to twist and cut the gate mark Wg.

Description

Technical Field

[0001] The present invention relates to a technique for removing gate marks on resin molded products.

Background Art

[0002] In recent years, from the viewpoints of weight reduction and thus fuel efficiency improvement, attempts have been made to change automotive parts such as bumpers from metal to resin. Since resin parts are usually molded by injection molding, gate marks often remain on the resin parts (resin molded products) obtained by injection molding. Therefore, it is necessary to remove the gate marks from the resin molded products taken out from the injection molding machine.

[0003] As a means for removing gate marks from resin molded products, for example, a method of cutting the gate marks with a blade such as nippers is known. With this method, it is possible to remove the gate marks by hand by an operator. However, when large parts such as bumpers are resin injection molded products, the number of gates (gate marks) increases, so it is not practical in terms of mass productivity to remove the gate marks one by one manually.

[0004] Therefore, recently, the removal operation by cutting the above-mentioned gate marks has been automated by a predetermined machine. For example, Patent Document 1 discloses a gate cutting device including a chuck member capable of holding a resin integral molded body having a gate (gate mark) and a product in a predetermined posture, and an air nipper capable of cutting the integral molded body held by the chuck member. When the integral molded body taken out from the injection molding machine is carried into a predetermined position, the chuck member grips the spool of the integral molded body and receives it. Then, after moving the integral molded body to the cutting position together with the chuck member by various cylinders, the gate at the root of the product is cut by the cutter of the air nipper, and the product can be taken out from the integral molded body.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Japanese Patent Publication No. 2005-96140 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] However, as mentioned above, when cutting gate marks with air nippers (cutters), uncut areas may occur depending on the location and shape of the gate. In this case, strict control of the cutting position is necessary to prevent uncut areas, or further finishing work after cutting may be required, which could lead to increased production costs. Furthermore, in order to handle various types of resin molded products, it is necessary to change the arrangement of multiple air nippers according to the cutting target, which made controlling the cutting position even more difficult.

[0007] In light of the above circumstances, this specification aims to address the technical problem of removing gate marks at low cost, while avoiding as much as possible any remaining gate residue, regardless of the gate's arrangement or shape. [Means for solving the problem]

[0008] The aforementioned problem is solved by the gate mark removal device according to the present invention. Specifically, this device is for removing gate marks remaining on a resin molded product from a resin molded product, and is characterized by comprising a holding part capable of holding the resin molded product, a gripping part capable of gripping the gate mark, a rotary gripping part having a rotary drive unit capable of rotating the gripping part around a predetermined axis, and a moving mechanism capable of moving the rotary gripping part, wherein the resin molded product is held by the holding part and the gate mark is gripped by the gripping part, and the gate mark can be twisted and cut by rotating the gripping part with the rotary drive unit.

[0009] As described above, the gate mark removal device according to the present invention is provided with a holding part for holding the resin molded product and a rotating gripping part that can rotate around a predetermined axis while gripping the gate mark. By rotating the gripping part while holding the resin molded product and gripping the gate mark, the gate mark can be twisted and cut. In this way, by twisting and cutting the gate mark, it is possible to remove the gate mark reliably while avoiding the occurrence of uncut parts as much as possible, compared to conventional cutting methods using nippers. Therefore, it is not necessary to strictly control the position of the gripping part, and post-processing such as finishing is generally unnecessary, so the gate mark can be removed at a low cost. Furthermore, as described above, by configuring the gate mark to be twisted, the gate mark can be cut without problems even if the position of gripping the gate mark is slightly off from the correct position, so the positioning of the gripping part (rotating gripping part) relative to the holding part can be performed in a short time, which improves productivity and reduces production costs. Of course, since the aforementioned rotating gripping section can be moved to a predetermined configuration by a moving mechanism, by arranging the rotating gripping section according to the number, position, and shape of the gate marks to be removed, the same gate mark removal device can be used to handle a wide variety of resin molded products.

[0010] Furthermore, the gate mark removal device according to the present invention may further include a multi-joint robot with a holding part attached to its tip, and the multi-joint robot may be taught so that it can move the gate marks to a position and orientation corresponding to the arrangement pattern of the rotating gripping parts.

[0011] By further providing a multi-joint robot with a holding part attached to its tip, and by performing predetermined teaching on this multi-joint robot, it becomes possible to accurately and quickly move the gate marks to a position and orientation corresponding to the arrangement pattern of the rotating gripping part. Therefore, with this configuration, by moving the rotating gripping part according to the arrangement of the gate marks (of the resin molded product) to be removed, and by moving the resin molded product held by the holding part to a predetermined position and orientation by the multi-joint robot according to the teaching of the corresponding pattern, it becomes possible to change the resin molded product (molding die) in a short time and accurately.

[0012] Furthermore, the aforementioned problem can also be solved by the gate mark removal method according to the present invention. That is, this method is a method for removing gate marks remaining on a resin molded product from a resin molded product, and is characterized by comprising the steps of: holding the resin molded product with a holding part; positioning a gripping part capable of gripping the gate mark at a predetermined position; gripping the gate mark of the resin molded product held by the holding part with the gripping part; and rotating one of the holding part and the gripping part around a predetermined axis while maintaining the other, thereby twisting and cutting the gate mark.

[0013] The gate mark removal method according to the present invention is provided with a holding part for holding a resin molded product and a gripping part capable of gripping the gate mark. By holding the resin molded product and gripping the gate mark, one of the holding part and the gripping part is maintained while the other is rotated around a predetermined axis, the gate mark can be twisted and cut. By twisting and cutting the gate mark in this way, it is possible to remove the gate mark reliably while avoiding the occurrence of uncut parts as much as possible, compared to conventional cutting methods using nippers. Therefore, it is not necessary to strictly control the position of the gripping part, and in principle post-processing such as finishing is unnecessary, so the gate mark can be removed at a low cost. Furthermore, as described above, with the method of twisting the gate mark, the gate mark can be cut without problems even if the position of gripping the gate mark is slightly off from the correct position. Therefore, the positioning of the gripping part relative to the holding part can be performed in a short time, which improves productivity and reduces production costs. [Effects of the Invention]

[0014] As described above, the gate mark removal device or gate mark removal method according to the present invention makes it possible to remove gate marks at low cost while avoiding as much remaining gate marks as possible, regardless of the arrangement or shape of the gate. [Brief explanation of the drawing]

[0015] [Figure 1]This is a plan view showing an example of the arrangement of a gate mark removal device according to one embodiment of the present invention. [Figure 2] Figure 1 is a front view of the main components of the gate mark removal device. [Figure 3] Figure 2 is a side view of the main part of the gate mark removal device shown. [Figure 4] Figure 2 is a plan view of the main components of the gate mark removal device shown. [Figure 5] Figure 2 is an enlarged front view of the main part of the gate mark removal device shown. [Figure 6] This is a front view showing an example of an injection-molded product for which gate marks are to be removed. [Figure 7] (a) an enlarged front view of the main part and (b) an enlarged cross-sectional view of the main part AA of a gate mark removal device according to another embodiment of the present invention. [Modes for carrying out the invention]

[0016] The gate mark removal device and gate mark removal method according to one embodiment of the present invention will be described below with reference to the drawings. In this embodiment, the target of the gate mark removal process is a relatively large resin molded product, such as an automobile bumper, in other words, a resin molded product that has multiple gates (gate marks) on a single resin molded product.

[0017] Figure 1 shows an example of the overall configuration and usage of a gate mark removal device 10 according to one embodiment of the present invention. As shown in Figure 1, the gate mark removal device 10 according to this embodiment comprises a gate mark removal device body 11, an articulated robot 12, and a control device 13. In this embodiment, the gate mark removal device body 11 and the articulated robot 12 are arranged around a resin injection molding machine 1 and a transport device 2 such as a conveyor that transports the resin injection molded product W obtained by molding with the injection molding machine 1 to the next process. In this illustrated example, the injection molding machine 1 is arranged on one side of the articulated robot 12, and the transport device 2 is arranged on the other side. The gate mark removal device body 11 is attached to the side of the base 3 that supports the articulated robot 12 (in this case, the side 3a on the transport device 2 side).

[0018] As shown in FIGS. 2 to 4, the gate trace removal device main body 11 includes a base portion 14 fixed to a fixed side (here, the base 3), a rotary gripping portion 15 provided on the base portion 14, and a moving mechanism 16 capable of moving the rotary gripping portion 15.

[0019] In this embodiment, the moving mechanism 16 is composed of a plurality of slide mechanisms 17 to 19. The rotary gripping portions 15 are respectively provided on the slide portions 17a to 19a of each slide mechanism 17 to 19, and the slide portions 17a to 19a slide on the rail portions 17b to 19b fixed to the base portion 14, so that each rotary gripping portion 15 can slide independently.

[0020] In this embodiment, as shown in FIGS. 2 to 4, a first slide mechanism 17 slidable along the vertical direction, and second and third slide mechanisms 18 and 19 located on the left and right of the first slide mechanism 17 and both slidable along the same horizontal direction are provided on the base portion 14. Two rotary gripping portions 15 are provided on each of the slide mechanisms 17 to 19. One of the two rotary gripping portions 15 is attached to each of the slide portions 17a to 19a such that its rotation axis (axis X) points vertically upward, and the other rotary gripping portion 15 is attached to each of the slide portions 17a to 19a such that its axis X is in the horizontal direction and orthogonal to the slide direction of the second and third slide mechanisms 18 and 19 (in FIG. 2, the direction penetrating the paper surface).

[0021] Note that the orientations of these rotary gripping portions 15 do not necessarily have to be the same. Also, they do not necessarily have to be fixed to the slide portions 17a to 19a so as to point in a certain direction. For example, as shown by the dashed-dotted line in FIG. 4, some of the rotary gripping portions 15 may be provided so as to be rotatable about a predetermined axis (an axis orthogonal to the axis X which will be the rotation center of the gripping portion 20 described later) with respect to the slide portions 18a and 19a.

[0022] The rotary gripping unit 15 is for gripping and cutting the gate mark Wg of an injection-molded product W held in a predetermined position and orientation, and has a gripping unit 20 and a rotary drive unit 21 that can rotate the gripping unit 20 around a predetermined axis X. Here, as shown in Figure 5, the gripping unit 20 is composed of a pair of chuck members 22, 22 which are, for example, thin plates, and by moving the pair of chuck members 22, 22 toward each other, it is possible to grip (chuck) the gate mark Wg placed between the pair of chuck members 22, 22. In this case, the chuck direction (gripping direction) of the pair of chuck members 22, 22 is perpendicular to the direction along the axis X of the rotary drive unit 21.

[0023] The drive sources for the gripping unit 20 and the rotary drive unit 21 may be the same or different. For example, both may be driven by compressed air in the factory, or by electricity. Therefore, a cylinder may be used as the actuator, or a motor may be used as the actuator. In any case, in this embodiment, any actuator can be used as long as it can exert sufficient gripping force, torque, and rotational speed to twist and cut the gate mark Wg, which is maintained in a predetermined position and orientation by the articulated robot 12 and the holding unit 23 described later. Furthermore, regarding the positioning accuracy of the rotation angle (phase), it is sufficient that the gate mark Wg can be introduced to a position where it can be gripped by the gripping unit 20, so a motor (actuator) capable of precise phase control such as a servo motor is not necessary, and a less expensive rotary actuator can be applied.

[0024] The holding part 23 is capable of holding the injection-molded product W, and in this embodiment, it is attached to the tip of the articulated robot 12. In other words, the holding part 23 is configured to be attachable to the tip of the articulated robot 12. This allows the holding part 23 to access the injection-molded product W from any direction and hold the injection-molded product W in a predetermined position and orientation. In the illustrated example, one side of the panel-shaped injection-molded product W is held, facilitating access to the gripping part 20 (rotating gripping part 15) from the other side. The means of holding the injection-molded product W by the holding part 23 is arbitrary, and known holding means such as mechanically gripping the injection-molded product W in the thickness direction, or directly holding the surface of the injection-molded product by suction, can be applied.

[0025] The control device 13 controls the operation of the articulated robot 12, as well as the gripping and rotational movements of the rotating gripping unit 15, and also controls the movement of the rotating gripping unit 15 by the moving mechanism 16. In this case, the control device 13 sets an arrangement pattern for the rotating gripping unit 15 according to the arrangement of gate marks Wg of the injection molded product W (relative positional relationship of multiple gate marks Wg) that is assumed in advance, and teaches the articulated robot 12 access operations, including the stopping position and posture of the injection molded product W, so that the multiple gate marks Wg are held in a position and posture according to this arrangement pattern. As a result, the control device 13 selects an arrangement pattern for the rotating gripping unit 15 according to the type of injection molded product W actually removed from the injection molding machine 1, and operates the articulated robot 12 with a taught operation pattern corresponding to the selected arrangement pattern, making it possible to move the injection molded product W to a predetermined position and posture.

[0026] Then, as described above, by moving the injection-molded product W to a predetermined position and orientation, the multiple gate marks Wg provided on the injection-molded product W are introduced into the gripping space of the gripping part 20 (in this embodiment, between the pair of chuck members 22, 22) which have been moved by the moving mechanism 16 based on a corresponding arrangement pattern (as shown by the dashed line in Figure 5). Therefore, from this state, the pair of chuck members 22, 22 are operated to move closer to each other to grip the gate marks Wg. Then, the holding part 23 holds the injection-molded product W including the gate marks Wg in a predetermined position and orientation, and with the corresponding gate marks Wg gripped by the gripping part 20, the rotation drive unit 21 rotates the gripping part 20 around a predetermined axis X, thereby twisting the gate marks Wg. As a result, the gate marks Wg are cut at the boundary between the gate marks Wg and the injection-molded product W (the product portion thereof), and the gate marks Wg are removed from the injection-molded product W. When multiple gripping parts 20 are gripping the same number of gate marks Wg, rotating these multiple gripping parts 20 will cut multiple gate marks Wg simultaneously. At this point, if there are still gate marks Wg that have not been cut, the articulated robot 12 and, if necessary, a predetermined number of rotating gripping parts 15 are moved to grip the remaining gate marks Wg, and the remaining gate marks Wg are cut by gripping and rotating as described above. In this way, all gate marks Wg remaining on the injection molded product W are removed.

[0027] As described above, the gate mark removal device 10 according to this embodiment can twist and cut the gate mark Wg while it is still attached to the injection molded product W. Therefore, compared to conventional cutting methods using nippers, it is possible to avoid leaving any uncut parts as much as possible and to reliably cut and remove the gate mark Wg at its base (the boundary with the injection molded product W body). In this case, it is not necessary to strictly control the position of the gripping part 20, and post-processing such as finishing is generally unnecessary, so the gate mark Wg can be removed at a low cost. Furthermore, even if the position where the gate mark Wg is gripped is slightly off from the correct position, the gate mark Wg can still be cut without any problems. Therefore, the positioning of the gripping part 20 (rotating gripping part 15) relative to the holding part 23 can be performed in a short time, which improves productivity and, consequently, reduces production costs. Of course, since the rotating gripping part 15 described above can be moved in a predetermined manner by the moving mechanism 16, the same gate mark removal device 10 can handle many types of injection molded products W by arranging the rotating gripping part 15 according to the number, position, and shape of the target gate mark Wg.

[0028] Furthermore, in this embodiment, a multi-joint robot 12 is provided, and a holding part 23 is provided at the tip of this multi-joint robot 12. This allows the multi-joint robot 12 to receive the reaction force generated on the holding part 23 side when each gate mark Wg is twisted. Therefore, even when multiple gate marks Wg are twisted simultaneously, each gate mark Wg can be cut without one twist affecting the other twists.

[0029] Furthermore, according to the configuration of this embodiment, the removal of the injection-molded product W from the injection molding machine 1, access to the gripping part 20 (gate mark removal device body 11) of the removed injection-molded product W, and the transport of the injection-molded product W from which the gate marks Wg have been removed to the next process (transfer to the transport device 2 for the next process in this embodiment) can be continuously performed by a single articulated robot 12 equipped with a holding part 23 at its tip. Therefore, a series of operations from the injection molding process to the gate mark removal process and the transport process to the next process can be performed smoothly and quickly.

[0030] Furthermore, by configuring the gate mark removal device body 11 to be thin and compact as in this embodiment, it becomes possible to install the gate mark removal device body 11 on the side of existing equipment, such as the side 3a of the base 3 of the articulated robot 12. If it can be installed in this way, it is not necessary to create new floor space for installing the gate mark removal device body 11. In addition, as shown in Figure 1, the gate mark removal device body 11 can be positioned between the removal position and the transfer position of the injection molded product W, so the movement time of the injection molded product W can be shortened and work efficiency can be further improved.

[0031] Furthermore, as in this embodiment, when the holding part 23 is provided at the tip of the articulated robot 12, the articulated robot 12 is taught so that the gate marks Wg can be moved to a position and orientation corresponding to the arrangement pattern of the rotating gripping part 15. This makes it possible to accurately and quickly move the gate marks Wg to a position and orientation corresponding to the arrangement pattern of the rotating gripping part 15. Therefore, with this configuration, by moving the rotating gripping part 15 according to the arrangement of the gate marks Wg of the injection molded product W to be removed, and by moving the injection molded product W held by the holding part 23 to a predetermined position and orientation by the articulated robot 12 according to the teaching of the corresponding pattern, it becomes possible to change the type of injection molded product W (changeover) in a short time and accurately.

[0032] Although one embodiment of the present invention has been described above, the gate mark removal device and gate mark removal method according to the present invention may also adopt configurations other than those described above, without departing from the spirit of the invention.

[0033] For example, in the above embodiment, after gripping the gate mark Wg with the gripping portion 20 (a pair of chuck members 22, 22), the gripping portion 20 is rotated around the axis X by the rotation drive unit 21 while the holding portion 23 is maintained in the position and orientation at which the gate mark Wg was gripped, thereby twisting and cutting the gate mark Wg. However, other cutting methods are also possible. Figure 7(a) shows an enlarged front view of a rotary gripping portion 15 according to one example (another embodiment of the present invention). The rotary gripping portion 15 according to this embodiment differs from the rotary gripping portion 15 shown in Figure 5 in that a pressing plate 24 for pressing down on the gate mark Wg is attached to at least one of the pair of chuck members 22, 22 that make up the gripping portion 20. In other words, with the rotating gripping part 15 according to this configuration, as shown in Figure 7(b), after introducing the gate mark Wg into the grippable space (between the pair of chuck members 22, 22) by the gripping part 20, and before performing the gripping operation by the gripping part 20, the holding part 23 is moved to move the injection molded product W body connected to the gate mark Wg, thereby pressing the gate mark Wg against the pressing plate 24, and the gate mark Wg can be bent (folded). In this case, the gate mark Wg is often bent at its base end, so by gripping the gate mark Wg in this state and rotating it around the axis X, it becomes possible to easily and with a high probability twist off the gate mark Wg starting from the bent part.

[0034] Furthermore, while the above embodiment illustrates the application of the present invention to a case where multiple gate marks Wg are formed on a single injection-molded product W, it is of course not limited to this. For example, although not shown in the figures, the present invention can be applied to injection-molded products W of a type that has one gate mark Wg on a single injection-molded product W. Alternatively, even when a single gate mark Wg branches and connects to multiple injection-molded products W, the gate mark removal device or gate mark removal method according to the present invention can be applied.

[0035] Furthermore, in this embodiment, an example was given in which the injection molded product W is held by the holding part 23 and the gate mark Wg is gripped by the gripping part 20, and the gripping part 20 is rotated around a predetermined axis X to twist off the gate mark Wg. However, the gate mark removal method according to the present invention is not limited to this. That is, if the conditions such as the number and arrangement of gate marks Wg are met, the gate marks Wg may be twisted and cut off by rotating the holding part 23 around a predetermined axis while the injection molded product W is held by the holding part 23 and the gate mark Wg is gripped by the gripping part 20. [Explanation of Symbols]

[0036] 1 injection molding machine 2. Conveying device 3 bases 3a side 10. Gate mark removal device 11. Main body of gate mark removal device 12 Articulated Robots 13 Control device 14 Base 15 Rotating grip part 16 Moving mechanism 17, 18, 19 Slide mechanism 17a, 18a, 19a Slide section 17b, 18b, 19b Rail section 20 Gripping part 21 Rotary drive unit 22,22 Chuck component 23 Holding part 24 Retaining plate W Injection molded product Wg Gate Ruins X axis

Claims

1. An apparatus for removing gate marks remaining on a resin molded product from the resin molded product, A holding portion capable of holding the aforementioned resin molded product, A rotating gripping unit having a gripping portion capable of gripping the gate mark and a rotational drive unit capable of rotating the gripping portion around a predetermined axis, The rotating gripping portion is equipped with a movable mechanism, A gate mark removal device is configured such that the resin molded product is held by the holding part and the gate mark is gripped by the gripping part, and the gripping part is rotated by the rotary drive part to twist and cut the gate mark.

2. A method for removing gate marks remaining on a resin molded product from the resin molded product, The step of holding the resin molded product in the holding part, The steps include: positioning a gripping part capable of gripping the gate mark in a predetermined position; The steps include: gripping the gate mark of the resin molded product held by the holding portion with the gripping portion; A method for removing gate marks, comprising the step of rotating one of the holding part and the gripping part around a predetermined axis while maintaining the other part, thereby twisting and cutting the gate mark.

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