JP6823255B2 - Manufacturing method of robot hand and molded product - Google Patents

Description

The present invention relates to a robot hand that can be used for deburring a molded product, and a method for manufacturing a molded product that includes a step of removing burrs using the robot hand.

In recent years, labor saving using robots has been promoted in factories. Patent Document 1 discloses an apparatus in which a pair of L-shaped arms grips a burr of a molded product and separates it from the molded product.

JP-A-2015-160422

The burr gripped by the pair of L-shaped arms can be removed from the arm by opening the pair of L-shaped arms and allowing them to fall freely. However, the burr may have an irregularly wavy shape, and in this case, the burr may be caught in the L-shaped portion of the arm and may not fall freely immediately.

The present invention has been made in view of such circumstances, and provides a robot hand capable of preventing burrs from being caught in an arm.

According to the present invention, the robot hand includes a base and a pair of arms provided on the base and for holding an object, and the pair of arms are attached to the base so that the distance between the arms is variable. Each of the pair of arms is provided with an elongated portion having an elongated shape and a protruding portion protruding from the elongated portion, and the protruding portion has a contact surface that abuts on the object and the contact surface from the contact surface. A robot hand is provided that includes an inclined surface that inclines toward the elongated portion in the direction of the base.

Since the robot hand of the present invention is provided with an inclined surface that inclines from the contact surface of the protruding portion toward the elongated portion in the direction of the base, it is possible to prevent burrs from being caught in the protruding portion.

Hereinafter, various embodiments of the present invention will be illustrated. The embodiments shown below can be combined with each other.
Preferably, the inclined surface has an angle of 15 to 75 degrees with respect to the longitudinal direction of the elongated portion. Robot hand.
Preferably, the projecting portion is provided adjacent to and adjacent to a vertical projecting portion that protrudes from the elongated portion and has an abutting surface so as to be perpendicular to the longitudinal direction of the elongated portion. An inclined portion having the inclined surface is provided.
Preferably, the contact surface has an uneven shape.
Preferably, the pair of arms is configured to open and close by rotating about a fulcrum provided on the base.
Preferably, the elongated portion has a thickness at the proximal end portion that is greater than the thickness at the portion between the proximal end portion and the protruding portion.
Preferably, it comprises a cutter that is fixed to the base and used to make a cut in the object.

According to another aspect of the present invention, a molding step of forming a molded body with burrs by molding a parison using a pair of split dies, and deburring to remove the burrs using the robot hand described above. A method for producing a molded product, which comprises a step, wherein a thin portion having a wall thickness smaller than that of the burr is provided between the molded body and the burr in the molding step, and the burr is removed in the burr removal step. There is provided a method for manufacturing a molded product, which is carried out by sandwiching and pulling the burr between the contact surfaces of the pair of arms and tearing the thin portion.
Preferably, the step of tearing the thin-walled portion is performed by applying an out-of-plane force of the thin-walled portion between the molded body and the burr to the thin-walled portion.
Preferably, the robot hand comprises a cutter that is fixed to the base and used to make a cut in the object, the molding is airing into the parison using a blow pin provided on the parting line. The burr removing step is performed after making a notch in a tubular portion formed at a portion corresponding to the periphery of the blow pin by using the cutter.
Preferably, the pair of split dies are configured such that when the pair of arms pinch and pull the burr, a catching portion on which the protruding portion is caught is formed on the burr.

FIG. 1A is a cross-sectional view showing a molding process (before mold clamping) in the method for manufacturing a molded product according to an embodiment of the present invention, and FIG. 1B is a right side view of a split mold 1 on the left side. FIG. 1A is a cross-sectional view corresponding to the cross section AA in FIG. 1B. The molding process (after mold clamping) in the method for producing a molded product according to an embodiment of the present invention is shown, and FIGS. 2A and 2B show cross sections corresponding to AA cross section and BB cross section in FIG. 1B, respectively. It is a figure. The molding process (after mold clamping) in the method for producing a molded product according to an embodiment of the present invention is shown, and FIGS. 3A to 3C show a CC cross section, a DD cross section, and an E- in FIG. 1B, respectively. It is sectional drawing corresponding to E cross section. It is a top view which shows the molded article 2bm with burrs obtained by the molding process in the manufacturing method of the molded article of one Embodiment of this invention. 2bm of the molded product with burrs in FIG. 4 is shown, and FIGS. 5A to 5C are a cross-sectional view taken along the line FF, a cross-sectional view taken along the line GG, and a cross-sectional view taken along the line HH in FIG. 4, respectively. 2bm of the molded product with burrs in FIG. 4 is shown, and FIGS. 5A to 5C are a cross-sectional view taken along the line II, a cross-sectional view taken along the line JJ, and a cross-sectional view taken along the line KK in FIG. 4, respectively. A robot hand 7 according to an embodiment of the present invention is shown, FIG. 7A shows a state in which a pair of arms 12 are closed, and FIG. 7B shows a state in which a pair of arms 12 are open. 8A to 8B are perspective views of the arm 12 in FIG. 7A. 9A-9D are cross-sectional views corresponding to FIG. 6A showing a step of removing the portion P1. A step of making a cut in the tubular portion 2d is shown, and FIGS. 10A and 10B are cross-sectional views corresponding to FIGS. 6C and 5C, respectively. 11A to 11C are cross-sectional views corresponding to FIG. 5B showing a step of removing the portion C.

Hereinafter, embodiments of the present invention will be described. The various features shown in the embodiments shown below can be combined with each other. In addition, the invention is independently established for each feature.

In the following description, the description will be centered on the method for manufacturing the molded product according to the embodiment of the present invention, and the robot hand according to the embodiment of the present invention will be described in detail in the deburring step.

The method for producing a molded product of the present embodiment includes a molding step and a deburring step.

<Molding process>
In this step, as shown in FIGS. 1 to 6, a molded body 2 bm with burrs is formed by molding the parison 2 using a pair of split dies 1.

The parison 2 can be formed by extruding the molten resin through a slit provided in the head. The molten resin can be formed by melt-kneading the raw material resin. The raw material resin is, for example, a thermoplastic resin such as polyolefin, and examples of the polyolefin include low-density polyethylene, linear low-density polyethylene, high-density polyethylene, polypropylene, ethylene-propylene copolymer and a mixture thereof. A foaming agent may or may not be added to the molten resin. When a foaming agent is added to the molten resin, the parison 2 becomes a foamed parison. The parison 2 may be tubular or on a sheet.

Although the pair of split molds 1 have the same shape in the present embodiment for convenience of explanation, these shapes may be different from each other. The split mold 1 includes a pinch-off portion 1a and a cavity 1b. By shaping the parison 2 into the shape of the cavity 1b, a molded body 2 m is obtained as shown in FIG.

The pinch-off portion 1a is a portion for forming the thin-walled portion 2a by sandwiching the parison 2 between a pair of split dies 1 and making the wall thickness extremely thin. The pinch-off portion 1a is provided so as to surround the cavity 1b, and a portion of the parison 2 outside the pinch-off portion 1a becomes a burr 2b in the molded body 2bm with burrs (see FIG. 4). The burrs 2b are formed in a randomly wavy shape except for the portion sandwiched by the mold. As shown in FIG. 4, the burr 2b includes an upper burr 2bt, a lower burr 2bb, a side burr 2bs, and a burr 2bi between two molded bodies 2m. The thin portion 2a is formed so that the wall thickness is smaller than that of the burr 2b. The wall thickness of the thin portion 2a is preferably, specifically, for example, 0.001, 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0. It is .6, 0.7, 0.8, 0.9, 1 mm, and may be within the range between any two of the numerical values exemplified here.

As shown in FIG. 1B, the pinch-off portion 1a is provided so as to surround substantially the entire circumference of the cavity 1b. Further, the pinch-off portions 1a are provided at three positions so as to extend laterally between the pair of cavities 1b. Further, the pinch-off portion 1a extends from the side end toward the cavity 1b at the center of the split mold 1 in the vertical direction. By providing such a pinch-off portion 1a extending in the lateral direction, a thin-walled portion 2a extending in the lateral direction is formed in the burr 2b in the molded body 2bm with burrs. Since the burrs 2b can be easily divided in the thin portion 2a, the burrs 2b can be easily removed.

The pinch-off portion 1a is provided so as to surround substantially the entire circumference of the cavity 1b, but when the blow pin 3 blow port 1d is provided on the parting line of the pair of split molds 1 (see FIGS. 1B and 3C). Since the pinch-off portion 1a is not provided at the portion of the blow port 1d, the thin-walled portion 2a is not formed either. The blow port 1d of each split mold 1 has, for example, a semi-cylindrical groove shape, and is a cylindrical opening for combining the pair of split molds 1. In the molded body 2bm with burrs, a tubular portion 2d is formed at a portion corresponding to the blow port 1d.

As shown in FIG. 1B, a groove portion 1c extending in a direction connecting the pair of molded bodies 2m is provided at a position adjacent to the center in the vertical direction between the pair of molded bodies 2m. As shown in FIG. 4, in the molded body 2bm with burrs, a ridge-shaped catching portion 2c is formed at a portion corresponding to the groove portion 1c.

When molding the molded body 2bm with burrs, as shown in FIG. 1A, the parison 2 is arranged between the pair of split dies 1 and the parison 2 is clamped in that state. 2 is molded to form a molded body with burrs 2 bm. The molding of the parison 2 may be a blow molding in which air is blown into the parison 2 using a blow pin 3, and the parison 2 is sucked under reduced pressure through a vacuum suction hole provided in the split mold 1 to form a cavity shape. It may be vacuum forming for shaping. When air is blown into the parison 2 using the blow pin 3, the blow port 1d for inserting the blow pin 3 may be provided on the parting line of the pair of split molds 1 and other parts ( For example, it may be provided on the cavity surface).

By opening the pair of split dies 1 after molding the parison 2, the molded body 2 bm with burrs can be taken out. The molded body 2bm with burrs is set on the deburring table 21 as shown in FIG. 9A. In the deburring table 21, the molded body 2bm with burrs is fixed by using the pressing member 22.

<Deburring process>
In this step, as shown in FIGS. 4 to 11, the robot hand 7 is used to remove the burrs 2b.

As shown in FIGS. 7 to 8, the robot hand 7 includes a hand base 8. An arm base 9 and a cutter 10 are attached to the hand base 8. The hand base 8 and the arm base 9 form a "base" in the claims. A pair of arms 12 are attached to the arm base 9. The pair of arms 12 have a function of sandwiching an object between them. The pair of arms 12 are attached to the arm base 9 so that the distance between them is variable. The cutter 10 is provided with a blade portion 10a at its tip.

Each arm 12 includes a mounting bracket 12a, an elongated portion 12b, and a protruding portion 12c. The mounting bracket 12a is mounted on the arm base 9 so as to be relatively rotatable. The mounting bracket 12a is rotatable relative to the arm base 9 at the fulcrum 13 provided on the arm base 9. The elongated portion 12b has an elongated shape and is fixed to the mounting bracket 12a. The base end portion 12b1 of the elongated portion 12b is fixed to the mounting bracket 12a. The base end portion 12b1 is thicker than the portion 12b2 between the base end portion 12b1 and the protrusion 12c. As a result, the strength of the arm 12 is increased. The elongated portion 12b may be directly mounted on the arm base 9 by omitting the mounting bracket 12a.

The protruding portion 12c is provided so as to protrude from the elongated portion 12b. The protrusion 12c of one arm 12 projects toward the protrusion 12c of the other arm 12. The protruding portion 12c is provided with a contact surface 12e that comes into contact with the object to be sandwiched. The pair of contact surfaces 12e are provided so as to face each other with the pair of arms 12 closed. The contact surface 12e is provided with an uneven shape so that the object to be sandwiched can be reliably held. The uneven shape is preferably a parallel groove composed of a plurality of parallel grooves. The parallel groove is preferably provided so as to extend in a direction perpendicular to the longitudinal direction of the elongated portion 12b. This is because the object can be held more reliably in this case.

The protruding portion 12c is provided with an inclined surface 12g that is inclined from the contact surface 12e toward the elongated portion 12b in the direction of the arm base 9. By providing such an inclined surface 12g, it is possible to prevent an object such as a burr 2b from being caught in the protruding portion 12c. The inclined surface 12g may be a flat surface or a curved surface. As shown in FIG. 7A, the angle α of the inclined surface 12g with respect to the longitudinal direction of the elongated portion 12b is preferably 15 to 75 degrees, more preferably 30 to 60 degrees, still more preferably 40 to 50 degrees.

The protrusion 12c is composed of one or a plurality of members. In the present embodiment, the protruding portion 12c is composed of a vertical protruding portion 12f and an inclined portion 12d. The vertical protrusion 12f protrudes from the elongated portion 12b so as to be perpendicular to the longitudinal direction of the elongated portion 12b. The vertical protrusion 12f is provided with a contact surface 12e. The inclined portion 12d is provided adjacent to the vertically protruding portion 12f. The inclined portion 12d is provided with an inclined surface 12g. The inclined portion 12d has a block shape and has a function of reinforcing the vertically protruding portion 12f. In the case of such a configuration, there is an advantage that the configuration of the present embodiment can be obtained only by attaching the inclined portion 12d to the existing L-shaped arm.

As shown in FIGS. 7A to 7B, the distance between the pair of contact surfaces 12e can be changed by rotating each of the pair of arms 12 in opposite directions with respect to the fulcrum 13. Therefore, as shown in FIG. 7B, an object is placed between the pair of abutting surfaces 12e with a gap between them, and then the pair of arms 12 so that the distance between the pair of abutting surfaces 12e is narrowed. By rotating the object, an object can be sandwiched between the pair of arms 12. As described above, in the present embodiment, the pair of arms 12 can be opened and closed by rotating around the fulcrum 13. In the present embodiment, the distance between the pair of contact surfaces 12e is changed by rotating the pair of arms 12, but the pair of arms 12 are translated by moving each of the pair of arms 12 in opposite directions. It may be configured to vary the spacing between the contact surfaces 12e.

As shown in FIG. 7, the robot hand 7 is used by being attached to the robot arm 6. The robot arm 6 has a function of moving the robot hand 7 when removing the burr 2b. The robot arm 6 may have any number of axes necessary for realizing the above functions, and preferably has 6 or more axes.

Here, a method of removing the burr 2b using the robot hand 7 will be described with reference to FIGS. 4 and 9. Since the removal of burrs 2b must be done within the interval of the molding cycle, the time that can be spent on removing burrs 2b is limited. Therefore, it is a serious problem from the viewpoint of productivity that the burr 2b is caught by the arm 12 and the work of removing the burr 2b is interrupted. In particular, in a molded body having a complicated shape and a large size, since the burr 2b is divided into a plurality of parts or the burr 2b is separated by changing the gripping place, the number of opening / closing operations of the arm 12 increases, and the burr The possibility that 2b gets caught in the arm 12 increases. Under such circumstances, a technique for suppressing the burr 2b from being caught by the arm 12 is desired.

As shown in FIG. 4, in the molded body 2 mb with burrs, there are burrs 2 bt on the upper side, burrs 2 bb on the lower side, burrs 2 bs on the side surface, and burrs 2 bi between the two molded bodies 2 m. Since it is not easy to remove all of these burrs 2b in one step, the burrs 2b are divided into a plurality of parts and removed one by one. In the present embodiment, the burr 2b is divided into the portions P1 to P4 by dividing the burr 2bs along the dotted line L. The site P1 is composed of burrs 2bt and burrs 2bs. The site P2 is composed of burrs 2bb and burrs 2bs. The site P3 is composed of the lower burr 2bi. The site P4 is composed of the upper burr 2bi. The order in which the sites P1 to P4 are removed is not particularly limited. The moving direction of the robot hand 7 when removing the portions P1 to P4 is not particularly limited, but it is preferable to move the robot hand 7 from the center to the end of the molded body 2 bm with burrs. In the example of FIG. 4, it is preferable that the burr 2b is torn from the molded body 2m by sandwiching the burr 2b with the robot hand 7 at a position near the straight line L and moving the robot hand 7 upward or downward as it is. However, the moving direction of the robot hand 7 can be appropriately set depending on the size and shape of the molded body 2 m, the portion of the burr 2b, and the pressing method (pressing position) of the pressing member 22.

When removing the portion P1, as shown in FIGS. 4 and 9A to 9B, the burr 2bs is pulled by the pair of arms 12 in the vicinity of the dotted line L to tear the thin portion 2a. By moving the robot hand 7 in this way, as shown in FIG. 9C, the portion P1 containing the burr 2bs is separated, and as shown in FIG. 9D, the pair of arms 12 are opened above the conveyor or the like for collecting the burr. The part P1 containing the burr 2bs is freely dropped. The burrs 2bs have a randomly wavy shape, and when the burrs 2bs are freely dropped, the burrs 2bs are likely to be caught by the vertical protrusion 12f of the arm 12. However, in the present embodiment, since the inclined surface 12g is provided, the portion P1 smoothly falls freely without the burrs 2bs getting caught in the arm 12. The thin-walled portion 2a can be easily torn by applying an out-of-plane force of the thin-walled portion 2a between the molded body 2m and the burr 2bs to the thin-walled portion 2a. For example, from the state shown in FIG. 9B, an out-of-plane force can be applied to the thin portion 2a by pressing the molded body 2m from above and moving the robot hand 7 upward.

The part P2 can be removed by the same method as that of the part P1, but in the part P2, the thin-walled portion 2a is divided by the tubular part 2d. Since the tearing stops at the tubular portion 2d, the portion P2 cannot be separated. Therefore, in the present embodiment, as shown in FIG. 10, the portion P2 is separated from the molded body 2m in the tubular portion 2d by making a notch in the tubular portion 2d using the cutter 10 before removing the portion P2. It makes things easier. Instead of making a cut in the tubular portion 2d using the cutter 10 of the robot hand 7, a cut may be made in the tubular portion 2d by another method. When a notch is made in the tubular portion 2d, the tearing of the thin-walled portion 2a does not stop at the tubular portion 2d, so that the portion P2 can be easily separated.

When removing the portion P3, as shown in FIGS. 11A to 11B, by pushing down the portion P4 with the arm 12, the thin portion 2a between the portions P3 and P4 is torn, and one of the pair of arms 12 is separated. It is placed below the site P3. Next, as shown in FIGS. 11B to 11C, the portion P3 is sandwiched by closing the pair of arms 12. By pulling up the part P3 as it is, the thin part 2a around the part P3 can be torn to separate the part P3, but the pair of arms 12 may slip with respect to the part P3 and the separation of the part P3 may not be successful. is there. However, in the present embodiment, the hooked portion 2c is provided on the portion P3, and when the pair of arms 12 slips on the portion P3, the protruding portion 12c of the arm 12 is caught on the hooked portion 2c. Stops the sliding of the arm 12. Therefore, in the present embodiment, failure of separation due to slippage of the arm 12 is suppressed. In the present embodiment, the hooked portion 2c has a convex shape, but any uneven shape that suppresses slippage can be used as the hooked portion 2c.

The site P4 can be removed in the same manner as the site P3.

By the above steps, a molded product 2 m from which the burrs 2b have been removed can be obtained. The removed burrs 2b can be transported by a conveyor or the like and used as a recycled raw material.

1: Split mold 1a: Pinch-off part 1b: Cavity 1c: Groove part 1d: Blow port 2: Parison 2a: Thin-walled part 2b, 2bt, 2bb, 2bs, 2bi: Deburring 2c: Hooking part 2d: Tube part 2m: Molded body 3 : Blow pin 6: Robot arm 7: Robot hand 8: Hand base 9: Arm base 10: Cutter 10a: Blade part 12: Arm 12a: Mounting bracket 12b: Elongated part 12b1: Base end part 12b2: Base end part and protrusion Between part 12c: Protruding portion 12d: Inclined portion 12e: Contact surface 12f: Vertical projecting portion 12g: Inclined surface 13: Support point 21: Deburring base 22: Pressing member

Claims (11)

A robot hand provided with a base and a pair of arms provided on the base and for holding an object.
The pair of arms are provided on the base so that the distance between them is variable.
Each of the pair of arms has an elongated portion and a protruding portion protruding from the elongated portion.
The protruding portion is a robot hand including a contact surface that abuts on the object and an inclined surface that is inclined from the contact surface toward the elongated portion in the direction of the base. The inclined surface relates to claim 1, wherein the slender portion has an angle of 15 to 75 degrees with respect to the longitudinal direction. Robot hand. The projecting portion is a vertical projecting portion that protrudes from the elongated portion and has the contact surface so as to be perpendicular to the longitudinal direction of the elongated portion, and the inclined surface that is provided adjacent to the vertical projecting portion. The robot hand according to claim 1 or 2, further comprising an inclined portion having. The robot hand according to any one of claims 1 to 3, wherein the contact surface has an uneven shape. The robot hand according to any one of claims 1 to 4, wherein the pair of arms is configured to be opened and closed by rotating around a fulcrum provided on the base. The elongated portion according to any one of claims 1 to 5, wherein the thickness at the base end portion is larger than the thickness at the portion between the base end portion and the protruding portion. Robot hand. The robot hand according to any one of claims 1 to 6, further comprising a cutter fixed to the base and used to make a cut in the object. A molding process of forming a molded body with burrs by molding a parison using a pair of split dies, and
A method for manufacturing a molded product, comprising a deburring step of removing the burrs using the robot hand according to any one of claims 1 to 7.
In the molding step, a thin portion having a wall thickness smaller than that of the burr is provided between the molded body and the burr.
A method for manufacturing a molded product, wherein in the burr removing step, the burr is removed by sandwiching and pulling the burr between the abutting surfaces of the pair of arms and tearing the thin portion. The method according to claim 8, wherein the step of tearing the thin-walled portion is performed by applying an out-of-plane force of the thin-walled portion between the molded body and the burr to the thin-walled portion. The robot hand comprises a cutter that is fixed to the base and used to make a cut in the object.
The molding is performed by blow molding in which air is blown into the parison using a blow pin provided on the parting line.
The method according to claim 8 or 9, wherein the deburring step is performed after making a notch in a tubular portion formed at a portion corresponding to the periphery of the blow pin by using the cutter. According to claims 8 to 10, the pair of split dies are configured such that when the pair of arms pinch and pull the burr, a catching portion on which the protruding portion is caught is formed on the burr. The method of description.