Method for removing shield foil and shield foil removing device

A shield foil removing device includes an opening and closing chuck configured to accommodate two wire cores surrounded by a shield foil in a space having a rectangular cross section orthogonal to an electric wire longitudinal direction, which is formed by closing, in such a direction that a longitudinal direction of the rectangular space and an arrangement direction of the two wire cores in a cross section coincide with each other, compresses the shield foil in a direction orthogonal to an arrangement direction of the two wire cores by reducing the rectangular space by a closing operation, and brings the shield foil into close contact with outer peripheral surfaces of the two wire cores to secure a gap continuous in a longitudinal direction of the shielded electric wire between both of outer peripheral curved surfaces adjacent to each other of the two wire cores and the shield foil.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority from Japanese patent application No. 2021-144892 filed on Sep. 6, 2021, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a method for removing a shield foil at a terminal of a shielded electric wire and a shield foil removing device.

BACKGROUND ART

Among types of communication electric wires to be mounted on a vehicle or the like, there is a shielded electric wire having a structure in which an outer periphery of a wire core (each conductor covered with an insulator) is covered with a metal shield foil such as an aluminum foil or a copper foil for improving a communication performance, and an outer periphery of the shield foil is covered with an insulating sheath. In addition, there is also a shielded electric wire having a structure in which a braid is inserted between a shield foil and an insulating sheath as a further shield material.

When terminal processing such as processing for attaching a connector to a terminal of a shielded electric wire is performed on this type of shielded electric wire, it is necessary to peel of the exposed shield foil from the inner wire core after removing the insulating sheath (in the case where a braid is present inside the insulating sheath, after the braid is folded back to cover the insulating sheath). The shield foil is wound so as to be in close contact with a signal line (wire core), and it is necessary to remove the shield foil so as not to damage the signal line (wire core) at the time of removal.

In the related art, the shield foil in this type of shielded electric wire is removed by manually cutting off the shield foil after the insulating sheath is peeled off. However, the manual removal of the shield foil has difficulty in dimensional accuracy and quality, is troublesome in work, and is more difficult to perform manual work as the shielded electric wire becomes thinner.

Therefore. Patent Literature 1 discloses a technique for cutting a shield foil by pressing a tip end surface of a shielded electric wire from which an insulating sheath within a predetermined length range from a tip end is removed against a conical concave surface (tapered surface=funnel-shaped wall), bringing a chuck that holds an outer periphery of the insulating sheath close to the conical concave surface, expanding the shield foil and a wire core by a repulsive force from the concave surface, and bringing the shield foil into contact with a cutting edge of a cutting blade by a stroke of the expansion.

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

However, according to the technique described in Patent Literature 1, since an expanded shape of the shield foil is not necessarily constant, there is a possibility that the shield foil is left unpeeled due to insufficient cutting or the wire core is damaged due to excessive cutting. In addition, the technique described in Patent Literature 1 is considered to be able to be implemented with a hard coaxial wire, but in a multi-core type shielded electric wire using thin wire cores, the shield foil may not expand and may not be established. In particular, in a case where two wire cores are twisted and then surrounded by the shield foil, untwisting causes the shield foil to expand in an irregular shape, making it difficult to accurately cut the shield foil.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for removing a shield foil and a shield foil removing device capable of accurately making a slit in a shield foil without damaging a wire core and peeling off the shield foil with a constant quality.

Solution to Problem

According to an embodiment of a method for removing a shield foil at a terminal of a shielded electric wire including two twisted wire cores, the shield foil surrounds an outer side of the two wire cores, and an insulating sheath covers an outer side of the shield foil. The method includes,a sheath removing step of removing the insulating sheath at the terminal of the shielded electric wire to expose the shield foil;a wire core untwisting step of untwisting the two wire cores from outside of the shield foil so that the two wire cores are parallel to each other from a root to a tip end of the exposed shield foil;a foil compressing step of accommodating the two wire cores surrounded by the shield foil in a space having a rectangular cross section orthogonal to an electric wire longitudinal direction, which is formed by closing an opening and closing chuck, in such a direction that a longitudinal direction of the rectangular space and an arrangement direction of the two wire cores in a cross section coincide with each other, compressing the shield foil from outside in a direction orthogonal to the arrangement direction of the two wire cores in the cross section by reducing the rectangular space, and bringing the shield foil into close contact with outer peripheral surfaces of the two wire cores in a direction orthogonal to the arrangement direction of the two wire cores in the cross section to secure a gap continuous in a longitudinal direction of the shielded electric wire between both of outer peripheral curved surfaces adjacent to each other of the two wire cores and the shield foil;a foil cutting step of abutting a cutting edge of a cutter on the shield foil from the outside at a position of the gap to make a slit in the shield foil along a longitudinal direction of the two wire cores; anda foil peeling step of peeling the shield foil with the slit from the two wire cores.

According to another embodiment of a shield foil removing device for removing a shield foil at a terminal of a shielded electric wire in which an insulating sheath at the terminal of the shielded electric wire is removed and two wire cores are parallel to each other from a root to a tip end of the exposed shield foil, the device includes:an opening and closing chuck openable and closable, and configured to accommodate two wire cores surrounded by the shield foil in a space having a rectangular cross section orthogonal to an electric wire longitudinal direction, which is formed by closing, in such a direction that a longitudinal direction of the rectangular space and an arrangement direction of the two wire cores in a cross section coincide with each other, compress the shield foil from outside in a direction orthogonal to an arrangement direction of the two wire cores in the cross section by reducing the rectangular space by a closing operation, and bring the shield foil into close contact with outer peripheral surfaces of the two wire cores to secure a gap continuous in a longitudinal direction of the shielded electric wire between both of outer peripheral curved surfaces adjacent to each other of the two wire cores and the shield foil.

DESCRIPTION OF EMBODIMENTS

FIG.1is an explanatory view of partial steps of a method for removing a shield foil according to the present embodiment, andFIGS.2A to2Fare side views illustrating all steps of the method for removing a shield foil. Noted that left side views of (a) to (c) inFIG.1are side views, and right side views of (a) to (c) inFIG.1and (d) inFIG.1are cross-sectional views as viewed from a tip end side of a shield foil and a wire core.FIG.2Ais a view showing a state after a sheath removing step of exposing the shield foil,FIG.2Bis a view showing a state after a wire core untwisting step of untwisting two wire cores in the exposed shield foil,FIG.2Cis a view showing a state after a foil cutting step of making slits in the shield foil along an electric wire longitudinal direction by the cutter,FIG.2Dis a view showing a state after a foil peeling step of blowing air to the shield foil with the slits to peel off the shield foil from the wire cores,FIG.2Eis a view showing a state during the foil peeling step of blowing air to the shield foil with the slits to peel off the shield foil from the wire cores, andFIG.2Fis a view showing a state in which the shield foil peeled off from the wire cores is cut off.

First, a shielded electric wire to be subjected to the method for removing a shield foil according to the present embodiment will be described.

As shown in (a) inFIG.1, a shielded electric wire1used in the present embodiment has a structure in which a pair of wire cores2in which outer peripheries of conductors2aformed of a stranded wire of annealed copper or the like are respectively covered with insulators2bare surrounded with a shield foil3such as an aluminum foil or a copper foil in a state of being spirally twisted, an outer side of the shield foil3is covered with a braid4, and an outer side of the braid4is covered with an insulating sheath5. The shield foil3is formed by, for example, winding a tape-shaped metal foil around the outer peripheries of the two wire cores2in a spiral shape while partially overlapping adjacent metal foil.

As shown in (a) inFIG.1andFIG.2A, in performing terminal processing, first, the insulating sheath5within a predetermined length range from a tip end of the shielded electric wire1is removed, and a folded portion of the braid4is covered from a tip end of the insulating sheath5to a base end side. As a result, the shield foil3is exposed within the predetermined length range from the tip ends of the insulating sheath5and the braid4(sheath removing step). Main terminal processing in the present embodiment is processing for peeling off the shield foil3within the predetermined length range from the wire cores2.

After the sheath removing step, a step of untwisting the two wire cores2inside the exposed shield foil3(wire core untwisting step) is performed.

In this wire core untwisting step, first, a portion of the insulating sheath5at a terminal of the shielded electric wire1(base end side of the shielded electric wire1) is held by an electric wire chuck (not shown). Then, the width of the shield foil3is measured by a sensor (not shown) at a position in a vicinity of a boundary between the insulating sheath5and the exposed shield foil3, that is, in a vicinity of a root N of the exposed shield foil3.

As the sensor, for example, a camera that captures an image of an outer surface of the shield foil3may be used. Then, an actuator that rotates the electric wire chuck rotates the shielded electric wire1around an axis, and stops the rotation at a rotation angle position of the shielded electric wire1at which a measured value indicating the width of the shield foil3becomes the maximum. Then, the width of the two wire cores2inside the shield foil3is also maximized, and the position at which the rotation is stopped corresponds to an arrangement direction of the two wire cores2at the root of the exposed shield foil3. Then, with this position as a reference, a twist of the two wire cores2in the exposed shield foil3is untwisted.

In the untwisting step, first, the sensor detects the arrangement direction of the two wire cores2at a tip end S of the exposed shield foil3. As the sensor, for example, a camera that captures an image of tip end surfaces of the shield foil3and the wire cores2in an axial direction can be used. An image processing device (not shown) acquires an image captured by the camera and detects the arrangement direction (that is, the arrangement) of the two wire cores2at the tip end of the shield foil3. Then, based on detection data, tip end portions of the wire cores2are rotated from the outside of the shield foil3in a direction (arrow A direction) in which the twist of the wire cores2is loosened. That is, the tip end portions of the shield foil3and the wire cores2are held by a chuck and rotated with respect to the base end side (root N side) of the shielded electric wire1.

The amount of rotation is determined in consideration of an amount by which the wire cores2return in a twisting direction due to a twisting tendency after the chuck at the tip end is opened, and is determined such that the arrangement directions of the wire cores2at the root N and the tip end S of the finally exposed shield foil3coincide with each other, and the two wire cores2from the root N to the tip end S of the exposed shield foil3are parallel to each other. In addition, a bending tendency of the two wire cores2from the root N to the tip end S of the exposed shield foil3may be corrected by a chuck that grips the tip end of the shield foil3, a chuck that grips another portion, or the like, as necessary.(b) inFIG.1andFIG.2Bshow the untwisted state of the wire cores2. When the twist of the two wire cores2are untwisted from the outside of the exposed shield foil3, the shield foil3is expanded in an irregular shape as exaggeratedly shown in a cross-sectional view on a right side of (b) inFIG.1. When cutting edges of the cutter abuts on the shield foil3in such an expanded state, the shield foil3may escape, and appropriate slits cannot be made in the shield foil3. Therefore, before the slits are made, a next foil compression step is performed.(c) inFIG.1shows a state in which the foil compression step is performed.

That is, in the foil compression step, as shown in (c) inFIG.1, a compressive force is applied by opening and closing chucks10A,10B from the outside of the shield foil3. As a result, gaps8that have each a substantially triangular cross section and are each continuous in the electric wire longitudinal direction are secured between both of outer peripheral curved surfaces adjacent to each other of the two wire cores2and the shield foil3.

FIGS.3A to3Care cross-sectional views orthogonal to the electric wire longitudinal direction, in whichFIG.3Ais a view showing a state before the compressive force is applied to the shield foil3by closing the opening and closing chuck10(10A,10B),FIG.3Bis a view showing a state where the compressive force is started to be applied to the shield foil3, andFIG.3Cis a view showing a state where slits21are made by a cutter20in a state in which the opening and closing chuck10(10A,10B) is closed and the shield foil3is compressed. In the following description, the opening and closing chuck10A and the opening and closing chuck10B will be described as the opening and closing chuck10when it is not necessary to distinguish between them.

As shown inFIGS.3A to3C, the opening and closing chuck10is openable and closable, and accommodates the exposed shield foil3in the expanded state due to untwisting of the wire cores2and the two wire cores2surrounded by the shield foil3, in a space15having a rectangular cross section orthogonal to the electric wire longitudinal direction, which is formed by closing in directions indicated by arrows inFIGS.3A to3C.

However, the opening and closing chuck10accommodates the shield foil3and the wire cores2in a state in which a longitudinal direction of a rectangular space and the arrangement direction of the two wire cores2in a cross section are adjusted to coincide with each other. That is, since the cross sections of the two wire cores2have a substantially elliptical shape, a rotation posture of the opening and closing chuck10is adjusted so that the longest direction of the elliptical shape coincides with the longitudinal direction of the rectangular space, and the shield foil3and the two wire cores2are gripped while being accommodated. At this time, the arrangement direction of the two wire cores2(a long axis direction of the ellipse) is confirmed by an image processing unit (not shown) acquiring an image captured by the camera.

That is, a shield foil removing device according to the present embodiment includes, around the opening and closing chuck10, a sensor that measures a width dimension of the exposed shield foil3on the root N side, and a camera that acquires an captured image of the tip end S surfaces of the two wire cores2surrounded by the exposed shield foil3. In the foil compression step, the direction of the shielded electric wire1in the cross section is adjusted by measuring the width dimension of the exposed shield foil3on the root side by a sensor. In addition, a direction of gripping the tip end of the exposed shield foil3and the two wire cores2is adjusted by the opening and closing chuck10by the image of the tip end surfaces of the two wire cores2surrounded by the exposed shield foil3captured by the camera.

Then, the rotation posture of the opening and closing chuck10is adjusted so that the arrangement directions of the two wire cores2at a position of the root N and a position of the tip end S of the exposed shield foil3coincide with each other and the two wire cores2from the root N to the tip end S of the exposed shield foil3are parallel to each other, and the opening and closing chuck10is closed (the operation of the arrows inFIGS.3A and3B) to reduce the rectangular space15. Then, the expanded shield foil3is compressed from the outside in a direction orthogonal to the arrangement direction of the two wire cores2in the cross section, and is brought into close contact with outer peripheral surfaces of the two wire cores2. As a result, the gaps8that have each a substantially triangular cross section and are each continuous in the longitudinal direction of the shielded electric wire1are secured between the shield foil3and both of the outer peripheral curved surfaces adjacent to each other of the two wire cores2. In the foil compression step, flat pressing surfaces11(seeFIG.3C) of the opening and closing chuck10parallel to each other uniformly press the shield foil3against the outer peripheral surfaces of the two wire cores2.

The opening and closing chuck10also has a function of sandwiching the entire two wire cores2in the longitudinal direction and correcting bending of the two wire cores2.

Next, when the compression of the shield foil3is completed, the foil cutting step is performed.

That is, as shown in (d) inFIG.1andFIG.3C, the cutting edges of the cutter20are abutted on the shield foil3from the outside at the positions of the gaps8having a substantially triangular cross section secured between the shield foil3and both of the outer peripheral curved surfaces adjacent to each other of the two wire cores2, and the slits21are made in the shield foil3along the longitudinal direction of the two wire cores2(the state ofFIG.2C).

After the slits21are made (the state ofFIG.4A), the opening and closing chuck10is opened, and the foil peeling step is performed.

That is, as shown inFIG.2E, air Air is blown toward the inside of the shield foil3in which the slits21are made, and as shown inFIG.2DandFIG.4B, the shield foil3is peeled off from the two wire cores2. At this time, due to the presence of the slits21, the shield foil3is easily peeled off from the wire cores2. Instead of blowing air, the shield foil3may be peeled off with a brush or the like.

The peeled shield foil3spreads in a state of being connected to the shield foil on an inner side of the insulating sheath5. Therefore, in a next foil separating step, the peeled shield foil3is cut off. That is, a chuck (not shown) grips the peeled shield foil3, and pulls the shield foil3in a certain direction of the insulating sheath5to cut off the shield foil3(state shown inFIG.2F). Therefore, a step of removing the shield foil3ends.

Among the above steps, an example of a portion of a device for performing the foil compression step is shown inFIGS.5to7.

FIG.5is a perspective view showing a partial configuration of the shield foil removing device including the opening and closing chuck,FIG.6is a front view of the opening and closing chuck portion of the device (the electric wire longitudinal direction), andFIG.7is a top view of the opening and closing chuck portion of the device.

As shown inFIGS.5to7, the opening and closing chuck10includes a pair of chucks10A,10B arranged symmetrically with the shielded electric wire1to be operated interposed therebetween. The chucks10A,10B are opened and closed by symmetrically approaching and separating from the shielded electric wire1held at a fixed position as indicated by arrows C. The pair of chucks10A,10B are configured by arranging a plurality of compression plates17at intervals in the axial direction of the shielded electric wire1. The compression plates17of the chuck10A (one) and the compression plates17of the chuck10B (other one) are alternately arranged in the axial direction of the shielded electric wire1. Further, by closing the pair of chucks10A,10B, the rectangular space15for accommodating the shield foil3and the two wire cores2is formed as shown inFIG.3C. In addition, the one compression plate17of the chuck10A is provided with the cutter20capable of projecting and retracting from the compression plate17in the direction of the shield foil3, so that the slits are made in the shield foil3when necessary.

As described above, according to the method for removing a shield foil of the present embodiment, since the cutting edges of the cutter20are abutted on the shield foil3compressed from the outside and brought into close contact with the wire core2, compared with a case where the slits are made in the shield foil while the shield foil3is expanded as in the related art, the shield foil3does not escape, and the cutting edges can be stably and reliably made to bite into the shield foil3. In addition, since the cutting edges of the cutter are abutted on the shield foil3at the positions of the gaps8having a substantially triangular cross section secured between both of the outer peripheral curved surfaces of the two wire cores2untwisted and held in parallel to each other and the shield foil3, the slits can be made in the shield foil3without damaging the wire cores2while inserting the cutting edges into the gaps8having a substantially triangular cross section. Therefore, the shield foil3surrounding the outer sides of the twisted wire cores2can be removed with a stable quality.

Since the slits21in the shield foil3can be made along the electric wire longitudinal direction from the root N to the tip end S of the exposed shield foil3, the shield foil3can be separated at a fixed position near a cut end of the insulating sheath5. As a result, it is possible to shorten the length of an electrically exposed portion, improve a connection quality with respect to a connector, and contribute to an improvement of the electrical characteristics of the connector.

Although manual work becomes more difficult as the shielded electric wire1becomes thinner, the wire core untwisting step, the foil compressing step, the foil cutting step, and the foil peeling step as well as the sheath removing step can be automated, so that all steps can be automated.

Since the arrangement directions of the two wire cores2at the root N and the tip end S of the exposed shield foil3are adjusted based on the data of the sensor or the camera, it is possible to make the slits21by the cutter20without damaging the wire cores2while maintaining the two wire cores2in a state of being parallel to each other with high accuracy.

Noted that the present invention is not limited to the embodiment described above, and modifications, improvements, and the like can be made as appropriate. In addition, materials, shapes, dimensions, numbers, arrangement positions, and the like of the respective constituent elements in the above-described embodiment are optional and are not limited as long as the present invention can be achieved.

According to an embodiment of a method for removing a shield foil (3) at a terminal of a shielded electric wire (1) including two twisted wire cores (2), the shield foil (3) surrounds an outer side of the two wire cores (2), and an insulating sheath (5) covers an outer side of the shield foil (3). The method includes,a sheath removing step of removing the insulating sheath (5) at the terminal of the shielded electric wire (1) to expose the shield foil (3);a wire core untwisting step of untwisting the two wire cores (2) from outside of the shield foil (3) so that the two wire cores (2) are parallel to each other from a root (N) to a tip end (S) of the exposed shield foil (3);a foil compressing step of accommodating the two wire cores (2) surrounded by the shield foil (3) in a space (15) having a rectangular cross section orthogonal to an electric wire longitudinal direction, which is formed by closing an opening and closing chuck (10,10A,10B), in such a direction that a longitudinal direction of the rectangular space (15) and an arrangement direction of the two wire cores (2) in a cross section coincide with each other, compressing the shield foil (3) from outside in a direction orthogonal to the arrangement direction of the two wire cores (2) in the cross section by reducing the rectangular space (15), and bringing the shield foil (3) into close contact with outer peripheral surfaces of the two wire cores (2) in a direction orthogonal to the arrangement direction of the two wire cores (2) in the cross section to secure a gap (8) continuous in a longitudinal direction of the shielded electric wire (1) between both of outer peripheral curved surfaces adjacent to each other of the two wire cores (2) and the shield foil (3);a foil cutting step of abutting a cutting edge of a cutter (20) on the shield foil (3) from the outside at a position of the gap (8) to make a slit (21) in the shield foil (3) along a longitudinal direction of the two wire cores (2); anda foil peeling step of peeling the shield foil (3) with the slit (21) from the two wire cores (2).

According to the method for removing a shield foil having the configuration of the above, since the cutting edge of the cutter is abutted on the shield foil compressed from the outside and brought into close contact with the wire core, unlike a case where the cutting edge of the cutter is abutted on the shield foil in a state where the shield foil is expanded, the shield foil does not escape, and the cutting edge can be stably and reliably made to bite into the shield foil. In addition, since the cutting edge of the cutter is abutted on the shield foil at the position of the gap having a substantially triangular cross section secured between both of the outer peripheral curved surfaces of the two wire cores untwisted and held in parallel to each other and the shield foil, the slit can be made in the shield foil without damaging the wire cores while inserting the cutting edge into the gap having a substantially triangular cross section. Therefore, the shield foil surrounding the outer sides of the twisted wire cores can be removed with a stable quality.

In addition, since the slit in the shield foil can be made along the electric wire longitudinal direction from the root to the tip end of the exposed shield foil, the shield foil can be separated at a fixed position near a cut end of the insulating sheath. As a result, it is possible to shorten the length of an electrically exposed portion, improve a connection quality with respect to a connector, and contribute to an improvement of the electrical characteristics of the connector. Although manual work becomes more difficult as the shielded electric wire becomes thinner, the wire core untwisting step, the foil compressing step, the foil cutting step, and the foil peeling step as well as the sheath removing step can be automated, so that all steps can be automated.

In the method for removing a shield foil according to the above,in the foil compression step, a direction of the shielded electric wire (1) in the cross section may be adjusted by measuring a width dimension of the exposed shield foil (3) on a root (N) side, and a direction in which the opening and closing chuck (10,10A,10B) grips the exposed shield foil (3) may be adjusted based on a captured image of tip end surfaces of the two wire cores (2) surrounded by the exposed shield foil (3).

According to the method for removing a shield foil having the configuration of the above, since the arrangement direction of the two wire cores (the longitudinal direction of the two wire cores in the cross section) between the root and the tip end of the exposed shield foil is adjusted, it is possible to make the slit in the shield foil by the cutter without damaging the wire cores while maintaining the two wire cores in a state of being parallel to each other with high accuracy.

According to another embodiment of a shield foil removing device for removing a shield foil (3) at a terminal of a shielded electric wire (1) in which an insulating sheath (5) at the terminal of the shielded electric wire (1) is removed and two wire cores (2) are parallel to each other from a root (N) to a tip end (S) of the exposed shield foil (3), the device includes, an opening and closing chuck (10,10A,10B) openable and closable, and configured to accommodate two wire cores (2) surrounded by the shield foil (3) in a space (15) having a rectangular cross section orthogonal to an electric wire longitudinal direction, which is formed by closing, in such a direction that a longitudinal direction of the rectangular space (15) and an arrangement direction of the two wire cores (2) in a cross section coincide with each other, compress the shield foil (3) from outside in a direction orthogonal to an arrangement direction of the two wire cores (2) in the cross section by reducing the rectangular space (15) by a closing operation, and bring the shield foil (3) into close contact with outer peripheral surfaces of the two wire cores (2) to secure a gap (8) continuous in a longitudinal direction of the shielded electric wire (1) between both of outer peripheral curved surfaces adjacent to each other of the two wire cores (2) and the shield foil (3).

According to the shield foil removing device having the configuration of the above, the foil compressing step can be performed by the opening and closing chuck, and it is possible to prepare to make a slit in the shield foil without damaging the wire core in the next foil cutting step.

The shield foil removing device according to the above may further include,a cutter (20) configured to cause a cutting edge to abut on the shield foil (3) from the outside at a position of the gap (8) to make a slit (21) in the shield foil (3) along a longitudinal direction of the two wire cores (2).

According to the shield foil removing device having the configuration of the above, the foil cutting step can be performed with the cutter.

The shield foil removing device according to the above may further include,a sensor configured to, when the exposed shield foil (3) is gripped by the opening and closing chuck (10,10A,10B), measure a width dimension of the exposed shield foil (3) on a root (N) side; anda camera configured to acquire a captured image of tip end surfaces of the two wire cores (2) surrounded by the exposed shield foil (3).

According to the shield foil removing device having the configuration of the above, the arrangement direction of the two wire cores can be detected at the positions of the root and the tip end of the exposed shield foil based on the detection result of the sensor and the captured image of the camera. Therefore, by reflecting these detection results in a holding posture of a holding chuck of the insulating sheath and a holding posture of the opening and closing chuck for gripping the shield foil, it is possible to make the slit in the shield foil by the cutter without damaging the wire cores while maintaining the two wire cores in a state of being parallel to each other with high accuracy from the root to the tip end of the shield foil.

According to the present invention, the slit can be accurately made in the shield foil without damaging the wire cores, and the shield foil can be peeled off with a constant quality. In addition, the shield foil can be cut off at a fixed position near the cut end of the insulating sheath. In addition, even when the shielded electric wire is thinned, automation can be achieved.