JP2020182964A - Welding tip - Google Patents

Abstract

To provide a welding tip which includes a tip body and a hard tip member, and is suitable for suppressing inconvenience caused with the retreat motion in a feeding direction of a welding wire.SOLUTION: A welding tip A1 of the present invention includes: a chip body 1 which has a connection part 11 to be mounted on a welding torch at a base end side as a feeding direction rear side X2 of a welding wire, and a first wire insertion hole 14 along an axis line Ox, and comprises a metallic material; and a tip member 2 which is mounted on a tip side as a feeding direction front side X1 in the chip body 1, has a second wire insertion hole 24 concentric with the first wire insertion hole 14, and comprises a metallic material harder than that of the chip body 1. The tip member 2 has a tip surface 22 along a plain face orthogonal to the axis line Ox, and an enlarged diameter hole 25 having one end connected to the tip of the second wire insertion hole 24, a radial direction dimension becoming larger toward the feeding direction front side X1, and the other end connected to the tip surface 22.SELECTED DRAWING: Figure 1

Description

The present invention relates to a welding tip used by attaching to a welding torch.

For example, a welding torch used in consumable electrode arc welding is configured such that a welding wire is sent out while receiving power from a so-called contact tip (welding tip). The welding wire is passed through the wire insertion hole of the welding tip, and is supplied with power by contact with the inner surface of the wire insertion hole on the tip end side of the welding tip. At the time of this power supply, the contact portion between the welding wire and the welding tip becomes hot, and the contact portion with the welding wire in the welding tip tends to be worn by the feeding of the welding wire. In view of such circumstances, a welding tip capable of suppressing wear of the tip tip portion has been proposed (see, for example, Patent Document 1).

The welding tip shown in Patent Document 1 has a structure in which a tip member is attached to the tip of the tip body. The tip member is a separate member different from the chip body, and is made of a metal material that is harder than the chip body. The tip member has a substantially cylindrical shape. A series of wire insertion holes are formed in the chip body and the tip member along the central axis. When arc welding is performed using a welding tip having such a configuration, the tip member that comes into contact with the welding wire and becomes hot during power supply is hard, so that it has excellent wear resistance and suppresses wear of the tip tip. Is possible.

Regarding the movement of the welding wire during arc welding, not only the welding wire is advanced in the feeding direction along the axis of the wire insertion hole of the welding tip (inching), but also the welding wire is retracted (retract). The operation of retracting the welding wire during arc welding is performed as necessary from the viewpoint of improving welding quality. For example, the welding wire may be advanced and then retracted once at the time of arc start, or the welding wire may be periodically repeated in the forward and backward operations during steady welding after the arc start.

In the welding tip described in Patent Document 1, the wire insertion hole of the tip member is opened through the tip surface of the tip member, and the opening is formed by the tip surface and the wire insertion hole. It has a shape with sharp corners at the intersection. When the welding wire retracts as described above, the surface of the welding wire is scraped at the corner of the tip opening of the tip member, and the scraps are pulled back in the wire insertion hole in the feeding direction. When the retreating operation of the welding wire is repeated, the above-mentioned shavings are clogged in the gap between the welding wire and the inner surface of the wire insertion hole, which hinders the feeding of the welding wire. Then, maintenance such as replacement of welding tips is required, which has been an obstacle to long-term use.

Japanese Unexamined Patent Publication No. 8-33983

The present invention has been conceived under such circumstances, and occurs in a welding tip provided with a tip body and a hard tip member as the welding wire retracts in the feeding direction. The main task is to provide a welding tip suitable for suppressing inconvenience.

In order to solve the above problems, the following technical means are adopted in the present invention.

The welding tip provided by the present invention has a connection portion for attaching to the welding torch on the base end side, which is the rear side in the feeding direction of the welding wire, and has a first wire insertion hole along the axis. The chip is made of a metal material and has a second wire insertion hole that is mounted on the tip side of the chip body that is the front side in the feeding direction and is concentric with the first wire insertion hole. A tip member made of a metal material harder than the main body is provided, and the tip member has a tip surface along a plane perpendicular to the axis and one end connected to the tip of the second wire insertion hole. It has a diameter-expanded hole in which the radial dimension increases toward the front in the feeding direction and the other end is connected to the tip surface.

In a preferred embodiment, the enlarged diameter hole includes a rounded portion leading to the second wire insertion hole.

In a preferred embodiment, the radius of curvature of the rounded portion is 0.3 mm or more.

In a preferred embodiment, the enlarged hole is an additional rounded portion that is located on the front side of the rounded portion in the feeding direction and has a smaller radius of curvature than the rounded portion. Including.

In a preferred embodiment, the radius of curvature of the rounded portion is in the range of 10 to 30 mm, and the radius of curvature of the additional rounded portion is in the range of 0.3 to 1 mm.

In a preferred embodiment, the length of the rounded portion in the feeding direction is in the range of 1 to 3 mm.

In a preferred embodiment, the welding wire is used to perform arc welding by advancing the welding wire forward and backward in the feeding direction.

According to the welding tip according to the present invention, in the hard tip member, a diameter-expanded hole is provided between the second wire insertion hole and the tip surface, and the tip opening of the tip member has a sharp shape. Absent. As a result, when the welding wire is retracted to the rear side in the feeding direction during arc welding, the surface of the welding wire is less likely to be scraped at the tip opening portion of the tip member. Therefore, it is possible to suppress clogging of shavings and the like caused by the backward movement of the welding wire in the feeding direction, and it can be used for a long period of time and has excellent durability.

Other features and advantages of the present invention will become more apparent with the detailed description given below with reference to the accompanying drawings.

It is a side view which shows 1st Embodiment of the welding tip which concerns on this invention, and a part is shown as a longitudinal sectional view. FIG. 3 is an enlarged cross-sectional view of the tip of the welding tip shown in FIG. A second embodiment of the welding tip according to the present invention is shown, and is a cross-sectional view similar to FIG. A third embodiment of the welding tip according to the present invention is shown, and is a cross-sectional view similar to FIG. A fourth embodiment of the welding tip according to the present invention is shown, and is a cross-sectional view similar to FIG.

Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.

1 and 2 show a first embodiment of a welding tip according to the present invention. The welding tip A1 of the present embodiment is used by assembling it to a welding torch (not shown). At the time of arc welding, a welding wire (not shown) is fed to the welding torch, and the welding wire passes through the welding tip A1 and is sent to the base metal side. In FIGS. 1 and 2, the left side in the drawing is the rear side of the welding wire in the feeding direction X (hereinafter, appropriately referred to as “feeding direction rear X2”), and is located on the base end side of the welding tip A1. Become. The right side in the figure is the front side of the welding wire in the feeding direction X (hereinafter, appropriately referred to as "feeding direction front X1"), and is the tip side of the welding tip A1.

The welding tip A1 includes a tip body 1 and a tip member 2. The chip body 1 and the tip member 2 are each made of a metal material.

The chip body 1 has a connecting portion 11, a body portion 12, a tip portion 13, and a first wire insertion hole 14 formed straddling these, and extends along the axis Ox as a whole. The connecting portion 11 is a portion connected to the tip of the tip body (not shown) of the welding torch. A male threaded portion 111 is formed on the outer periphery of the connecting portion 11, and the welding tip A1 is assembled to the welding torch by screwing the male threaded portion 111 into the female threaded portion (not shown) of the tip body. A central hole 15 for passing a welding wire is formed in the connecting portion 11. The center hole 15 has a tapered shape, and a welding wire (not shown) fed to the welding torch is fed to the body portion 12 side while being centered and guided in the center hole 15.

The body portion 12 is connected to the tip of the connecting portion 11. The outer peripheral surface of the body portion 12 has a polygonal cross section. The tip portion 13 is connected to the tip of the body portion 12. The tip portion 13 has a tapered outer circumference, and has a mounting recess 131 and a locking portion 132. The mounting recess 131 is a substantially columnar recess for mounting the tip member 2, and the tip is open. The locking portion 132 is a portion of the tip portion 13 in which the mounting recess 131 is formed and projects inward in the radial direction, and is fitted in the locking recess 23 of the tip member 2 described later.

The first wire insertion hole 14 is a through hole having a circular cross section through which the welding wire can pass, and is formed along the axis Ox. The first wire insertion hole 14 is connected to the central hole 15 at the connection portion 11 and extends to the tip edge at the tip portion 13 where the mounting recess 131 is formed. The diameter of the welding wire passing through the first wire insertion hole 14 is, for example, about 0.8 to 1.6 mm, and the inner diameter of the first wire insertion hole 14 is, for example, about 1.0 to 1.8 mm. The material of the chip body 1 is, for example, an alloy containing copper and chromium (chromium copper). However, the material of the chip body 1 is not limited. The chip body 1 is more conductive than the welding wire.

The tip member 2 is attached to the tip portion 13 of the chip body 1. The tip member 2 has a tubular shape extending along the axis Ox, and most of the tip member 2 is housed in the mounting recess 131 of the chip body 1. The tip member 2 has a base end surface 21, a tip surface 22, a locking recess 23, a second wire insertion hole 24, and a diameter expansion hole 25. The base end surface 21 and the tip end surface 22 are along a plane that is perpendicular to the axis Ox. The base end surface 21 faces the rear X2 in the feeding direction, and is in contact with the inner end surface (the rear X2 side in the feeding direction) of the mounting recess 131 of the chip body 1. The tip surface 22 faces the front X1 in the feeding direction, and is located at the front X1 side end in the feeding direction in the welding tip A1. The locking recess 23 is a portion whose outer circumference is recessed on the tip side of the tip member 2. The locking portion 132 of the chip body 1 is fitted in the locking recess 23. As a result, the tip member 2 is prevented from falling off from the chip body 1.

The second wire insertion hole 24 is a through hole having a circular cross section through which the welding wire can pass. The second wire insertion hole 24 is formed along the axis Ox and is concentric with the first wire insertion hole 14 of the chip body 1. The inner diameter of the second wire insertion hole 24 is the same as that of the first wire insertion hole 14, and the second wire insertion hole 24 is continuously connected to the tip of the first wire insertion hole 14. The second wire insertion hole 24 is formed in a portion of the tip member 2 excluding the region near the tip.

The enlarged diameter hole 25 is a through hole formed along the axis Ox, and its radial dimension increases toward the front X1 in the feeding direction. The base end (one end) of the enlarged diameter hole 25 is connected to the tip of the second wire insertion hole 24. The tip (other end) of the enlarged diameter hole 25 is connected to the tip surface 22.

As shown in FIG. 2, in the present embodiment, the enlarged diameter hole 25 includes a rounded shape portion 251 and a rounded shape portion 252. Each of the rounded portions 251,252 is a portion whose vertical cross-sectional shape including the axis Ox is an arc shape. In addition, in FIG. 2, different hatching is attached to the rounded shape portion 251 and the rounded shape portion 252.

The rounded portion 251 is smoothly connected to the tip of the second wire insertion hole 24. More specifically, the tangent line of the connection portion with the second wire insertion hole 24 in the vertical cross section of the rounded shape portion 251 is along the second wire insertion hole 24. In the present embodiment, the radius of curvature of the rounded portion 251 is, for example, in the range of 10 to 30 mm, preferably 15 to 25 mm. Here, the radius of curvature of the rounded shape portion 251 means the radius of the arc shape (arc shape of the illustrated cross section) of the vertical cross section including the axis Ox in the rounded shape portion 251. Is the same. Further, the length L1 of the rounded shape portion 251 in the feeding direction X is, for example, in the range of 1 to 3 mm.

The rounded shape portion 252 is located on the front X1 side in the feeding direction with respect to the rounded shape portion 251. In the rounded portion 252, the rear X2 side end in the feeding direction is smoothly connected to the rounded shape portion 251 and the front X1 side end in the feeding direction is smoothly connected to the tip surface 22. In the present embodiment, the radius of curvature of the rounded portion 252 is smaller than the radius of curvature of the rounded portion 251 and is, for example, in the range of 0.3 to 1 mm. The rounded shape portion 252 having such a configuration corresponds to the additional rounded shape portion referred to in the present invention.

The tip member 2 is made of a metal material that is harder than the tip body 1. Examples of the material of such a tip member 2 include an alloy containing copper and tungsten (copper tungsten). However, the material of the tip member 2 is not limited. The tip member 2 is more conductive than the welding wire.

The welding tip A1 having the above configuration is manufactured by, for example, the following procedure. First, the chip body 1 and the tip member 2 which are separate members are prepared. Here, the first wire insertion hole 14 is not formed in the chip body 1, and the second wire insertion hole 24 and the diameter expansion hole 25 are not formed in the tip member 2. Further, the portion where the locking portion 132 is not formed at the tip portion 13 of the chip body 1 and the mounting recess 131 is formed at the tip portion 13 is a tubular shape having a constant inner diameter. Next, the tip member 2 is attached to the chip body 1. Here, the tip member 2 is fitted into the mounting recess 131 of the tip portion 13 of the tip body 1 and the tip portion 13 is crimped. Specifically, while pressing the base end surface 21 of the tip member 2 against the back end surface of the mounting recess 131, the tubular tip portion of the tip portion 13 is crimped to the locking recess 23 of the tip member 2. As a result, the locking portion 132 is fitted into the locking recess 23, and the tip member 2 is integrally fixed to the chip body 1. The above caulking operation may be performed a plurality of times. In a state where the tip member 2 is fixed to the tip body 1, the tip body 1 and the tip member 2 are in close contact with each other without a gap.

Next, the first wire insertion hole 14 and the second wire insertion hole 24 are formed in the chip body 1 and the tip member 2. The first wire insertion hole 14 and the second wire insertion hole 24 are formed by cutting with a drill having an outer diameter dimension corresponding to the inner diameter dimension of the first wire insertion hole 14 and the second wire insertion hole 24. .. Next, a diameter-expanding hole 25 is formed at the tip of the tip member 2. The enlarged diameter hole 25 is formed, for example, by cutting with a cutting tool having a cutting edge portion corresponding to the vertical cross-sectional shape of the enlarged diameter hole 25.

Next, the operation of the welding tip A1 of the present embodiment will be described.

The welding tip A1 is used by being assembled to a welding torch (not shown). When performing arc welding using the welding tip A1, the welding wire passes through the first wire insertion hole 14 and the second wire insertion hole 24 while passing through the tip side of the welding tip A1 (forward X1 side in the feeding direction). ), Power is received by contact with the inner surface of the second wire insertion hole 24. The welding tip A1 is preferably used when the welding wire is advanced toward the front X1 side in the feeding direction and retracted toward the rear X2 side in the feeding direction during arc welding. The operation of retracting the welding wire during arc welding includes the case where the welding wire is advanced and then retracted once at the time of arc start, and the case where the welding wire is periodically repeated in the forward and backward operations during steady welding after the arc start. is there.

In the present embodiment, the hard tip member 2 mounted on the tip 13 of the tip body 1 has a diameter-expanding hole 25. The diameter-expanding hole 25 has its base end (end on the rear X2 side in the feeding direction) connected to the second wire insertion hole 24 of the tip member 2, and the diameter-expanding hole 25 is radially forward toward the feeding direction X1. The dimensions increase. The tip of the enlarged diameter hole 25 (the end on the front X1 side in the feeding direction) is connected to the tip surface 22 which is perpendicular to the axis Ox.

According to such a configuration, the enlarged diameter hole 25 is provided between the second wire insertion hole 24 and the tip surface 22, and the tip opening of the tip member 2 is not sharp. As a result, when the welding wire is retracted to the rear X2 side in the feeding direction during arc welding, the surface of the welding wire is less likely to be scraped at the tip opening portion of the tip member 2. Therefore, it is possible to suppress clogging of shavings and the like caused by the backward operation of the welding wire in the rearward X2 in the feeding direction, and the welding tip A1 can be used for a long period of time and has excellent durability.

The portion of the enlarged diameter hole 25 connected to the second wire insertion hole 24 is a rounded portion 251. As a result, the enlarged diameter hole 25 (R-shaped portion 251) is smoothly connected at the tip of the second wire insertion hole 24. According to such a configuration, when the welding wire is retracted to the rear X2 side in the feeding direction, the scraping of the surface of the welding wire is further reduced, and the durability of the welding tip A1 is further improved.

The enlarged diameter hole 25 further has a rounded shape portion 252. The rounded shape portion 252 is located on the front X1 side in the feeding direction with respect to the rounded shape portion 251 and has a radius of curvature smaller than that of the rounded shape portion 251. In the present embodiment, the rounded shape portion 251 and the rounded shape portion 252 having different radii of curvature are provided, and the rounded shape portion 251 having a relatively large radius of curvature is connected to the tip of the second wire insertion hole 24. Such a configuration is more preferable in order to reduce the scraping of the surface of the welding wire when the welding wire is retracted to the rear X2 side in the feeding direction. Further, by providing the radius-shaped portion 252 having a relatively small radius of curvature on the tip side, it is possible to prevent the total length of the enlarged diameter hole 25 in the feeding direction X from becoming long. As a result, the distance from the feeding point to the base metal due to the contact of the welding wire with the inner surface of the second wire insertion hole 24 becomes relatively short, and an increase in the amount of power supplied can be suppressed.

As specific dimensions of each part of the enlarged diameter hole 25, for example, the radius of curvature of the rounded portion 251 is in the range of 10 to 30 mm, and the radius of curvature of the rounded shape portion 252 is in the range of 0.3 mm. Further, the length L1 of the rounded shape portion 251 in the feeding direction X is in the range of 1 to 3 mm. According to such a configuration, the above-mentioned effects can be appropriately obtained by providing the radius-shaped portions 251,252 having different radii of curvature while suppressing an increase in the size of the tip member 2 itself.

In order to confirm the effect of this embodiment, an experiment on durability was conducted using the welding tip A1 and the welding tip having the conventional configuration. As a welding tip having a conventional structure, a tip having a shape in which the wire insertion hole formed in the tip member extends straight to the tip surface and the angle of the tip opening of the tip member is sharp is prepared without providing the diameter expansion hole 25. Using the welding tip having such a conventional configuration, the forward operation and the backward operation of the welding wire were repeated at a predetermined cycle during steady welding after the arc start. The forward / backward movement of the welding wire during steady welding was 100 reciprocations per second, and steady welding was continued for about 60 seconds in one welding. That is, in one welding operation, the forward / backward operation of the welding wire was about 6,000 times. With the welding tip of the conventional configuration, when such welding work was repeated, the wire feeding was hindered when the welding work was performed 1,200 times. The number of forward / backward movements (total number) of the welding wire at that time was about 7.2 million times.

On the other hand, using the welding tip A1 of the present embodiment, the forward movement and the backward movement of the welding wire were repeated at the same cycle as in the case of the welding tip having the above-mentioned conventional configuration during steady welding after the arc start. The duration of one welding operation was also set to about 60 seconds as in the case of the above-mentioned conventional configuration. That is, in one welding operation, the forward / backward operation of the welding wire was about 6,000 times. With the welding tip A1, there was no problem in wire feeding at the time when the welding work was performed 4,800 times (the number of forward / backward movements of the welding wire was about 28.8 million times). As a result, it was confirmed that the welding tip A1 of the present embodiment has more than four times the durability of the welding tip of the conventional configuration when the welding wire is repeatedly retracted.

FIG. 3 shows a second embodiment of the welding tip according to the present invention. In the welding tip A2 of the present embodiment, the configuration of the enlarged diameter hole 25 in the tip member 2 is different from that of the welding tip A1 of the above embodiment. In addition, in FIG. 3 and later, the same or similar elements as those in the above-described embodiment are designated by the same reference numerals, and the description thereof will be omitted as appropriate.

In the welding tip A2, the enlarged diameter hole 25 has only the rounded shape portion 251. The rounded portion 251 is smoothly connected to the tip of the second wire insertion hole 24. The radius of curvature of the rounded portion 251 is about 10 to 30 mm, and the total length of the enlarged diameter hole 25 (rounded portion 251) in the feeding direction X is about 1 to 3 mm.

In the tip member 2 of the welding tip A2, a diameter-expanded hole 25 is provided between the second wire insertion hole 24 and the tip surface 22, and the tip opening of the tip member 2 is not sharp. As a result, when the welding wire is retracted to the rear X2 side in the feeding direction during arc welding, the surface of the welding wire is less likely to be scraped at the tip opening portion of the tip member 2. Therefore, it is possible to suppress clogging of shavings caused by the backward operation of the welding wire in the rearward X2 in the feeding direction, and the welding tip A2 can be used for a long period of time and has excellent durability.

FIG. 4 shows a third embodiment of the welding tip according to the present invention. In the welding tip A3 of the present embodiment, the configuration of the enlarged diameter hole 25 in the tip member 2 is different from that of the welding tip A1 of the above embodiment.

In the welding tip A3, the enlarged diameter hole 25 includes a rounded shape portion 251 and a tapered shape portion 253. The tapered shape portion 253 is located on the front X1 side in the feeding direction with respect to the round shape portion 251. The tapered shape portion 253 is a portion having a linear vertical cross-sectional shape including the axis Ox.

In the tip member 2 of the welding tip A3, a diameter-expanded hole 25 is provided between the second wire insertion hole 24 and the tip surface 22, and the tip opening of the tip member 2 is not sharp. As a result, when the welding wire is retracted to the rear X2 side in the feeding direction during arc welding, the surface of the welding wire is less likely to be scraped at the tip opening portion of the tip member 2. Therefore, it is possible to suppress clogging of shavings and the like caused by the backward operation of the welding wire in the rearward X2 in the feeding direction, and the welding tip A3 can be used for a long period of time and has excellent durability.

FIG. 5 shows a fourth embodiment of the welding tip according to the present invention. In the welding tip A4 of the present embodiment, the configuration of the enlarged diameter hole 25 in the tip member 2 is different from that of the welding tip A1 of the above embodiment.

In the welding tip A4, the enlarged diameter hole 25 has only the rounded shape portion 251. In the rounded shape portion 251, the rear X2 side end in the feeding direction is smoothly connected to the tip of the second wire insertion hole 24, and the front X1 side end in the feeding direction is smoothly connected to the tip surface 22. The radius of curvature of the rounded portion 251 is 0.3 mm or more, preferably in the range of 0.3 to 1 mm.

In the tip member 2 of the welding tip A4, a diameter-expanded hole 25 is provided between the second wire insertion hole 24 and the tip surface 22, and the tip opening of the tip member 2 is not sharp. As a result, when the welding wire is retracted to the rear X2 side in the feeding direction during arc welding, the surface of the welding wire is less likely to be scraped at the tip opening portion of the tip member 2. Therefore, it is possible to suppress clogging of shavings and the like caused by the backward operation of the welding wire in the rearward X2 in the feeding direction, and the welding tip A4 can be used for a long period of time and has excellent durability.

Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to the above-described embodiments, and any modification within the scope of the matters described in each claim is the scope of the present invention. Is included in.

A1, A2, A3, A4: Welding tip, 1: Chip body, 11: Connection part, 13: Tip part, 14: First wire insertion hole, 2: Tip member, 22: Tip surface, 24: Second wire Insertion hole, 25: Expanded hole, 251: R-shaped part, 252: R-shaped part (additional R-shaped part), L1: Length (length of R-shaped part in feeding direction), Ox: Axis line, X : Feeding direction, X1: Forward in feeding direction, X2: Rear in feeding direction

Claims (7)

A chip body made of a metal material, having a connection portion for attaching to the welding torch on the base end side, which is the rear side in the feeding direction of the welding wire, and having a first wire insertion hole along the axis.
The chip body is made of a metal material that is mounted on the tip side, which is the front side in the feeding direction, has a second wire insertion hole concentric with the first wire insertion hole, and is harder than the chip body. With a tip member,
The tip member has a tip surface along a plane perpendicular to the axis and
A welding tip having a diameter-expanded hole, one end of which is connected to the tip of the second wire insertion hole and the radial dimension is increased toward the front in the feeding direction, and the other end is connected to the tip surface. The welding tip according to claim 1, wherein the enlarged diameter hole includes a rounded portion connected to the second wire insertion hole. The welding tip according to claim 2, wherein the radius of curvature of the rounded portion is 0.3 mm or more. Claim 2 or 3 includes an additional rounded shape portion in which the enlarged diameter hole is located on the front side of the rounded shape portion in the feeding direction and has a radius of curvature smaller than that of the rounded shape portion. The welding tip described in. The welding tip according to claim 4, wherein the radius of curvature of the rounded portion is in the range of 10 to 30 mm, and the radius of curvature of the additional rounded portion is in the range of 0.3 to 1 mm. The welding tip according to claim 5, wherein the length of the rounded portion in the feeding direction is in the range of 1 to 3 mm. The welding tip according to any one of claims 1 to 6, wherein the welding wire is used for performing arc welding by advancing the welding wire forward and backward in the feeding direction and retreating the welding wire to the rear side.

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