Patent Description:
In recent years, electronic circuits on which electronic components are mounted have been incorporated in various types of devices. In a step of forming an electronic circuit, in order to perform, for example, processing for joining a lead wire to a wiring pattern (land) on a board, soldering using a soldering iron is performed. In order to mechanically realize a soldering step, a solder processing device having a portion of a soldering tip is utilized.

For example, the solder processing device as described above is configured such that a solder piece (piece obtained by cutting a wire solder in which a layer of a flux is provided within a solder layer) is heated in a posture where the solder piece is erected within the soldering tip and that thus the molten solder is supplied downward. In this way, it is possible to realize the soldering step on the board arranged below.

<CIT> and <CIT> disclose a soldering wire containing flux.

<CIT> discloses a soldering gun which is constituted such that a cylindrical through-hole is provided on the center axis of the soldering gun, a tip of the soldering gun is formed in a cone or pyramid shape, a diameter of a through-hole opening on the tip is <NUM>-<NUM> and the diameter of a plane including the opening is <NUM>-<NUM>, and the material is ceramic, stainless steel, titanium or chromium which can hardly be wetted by the solder.

When as described above, the solder piece is heated in the posture where the solder piece is erected within the soldering tip, the flux having a relatively low melting point starts to flow out from the solder piece. When the flux appropriately flows out from the upper end or the side surface of the solder piece, the flux excellent in wettability is appropriately interposed between the inner wall of the soldering tip and the solder piece. Consequently, contactability between the inner wall of the soldering tip and the solder piece is enhanced, and thus heat is sufficiently transmitted from the soldering tip to the solder piece, with the result that it is possible to appropriately heat and melt the solder piece.

However, when the solder piece is heated in the posture where the solder piece is erected within the soldering tip, it is likely that the flux easily flows out from the lower end of the solder piece. In this case, the flux flows downward of the solder piece, and thus it is unlikely that the flux is interposed between the inner wall of the soldering tip and the solder piece.

Consequently, it is likely that heat is not sufficiently transmitted from the soldering tip to the solder piece and that thus the solder piece cannot be appropriately heated and melted. In view of the foregoing problem, the present invention has an object to provide a solder processing method, wherein a solder piece in a posture where the solder piece is erected within a soldering tip can more reliably be heated and melted. This object is achieved by a solder processing method according to the independent claim. Preferred embodiments are defined in the respective dependent claims.

In a solder processing method according to the present invention, a plurality of solder pieces in which a layer of a flux is provided within a tubular solder layer are sequentially supplied into a substantially tubular soldering tip that can be heated and that is extended vertically, within the soldering tip, the solder pieces are erected such that on the solder piece which is first supplied, the solder piece which is subsequently supplied sits and the heat of the soldering tip is used to melt the solder pieces such that the molten solder is supplied downward.

In this configuration, it is possible to more reliably heat and melt the solder pieces in a posture where they are erected within the soldering tip.

In the configuration described above, more specifically, the solder piece supply portion may be provided to sequentially produce a first solder piece and a second solder piece by cutting a wire solder, and to supply the first and second solder pieces into the soldering tip.

In the configuration described above, more specifically, the solder piece supply portion may cut the wire solder such that the first solder piece differs in length from the second solder piece.

In the configuration described above, more specifically, a terminal protruded upward may be soldered to a board, and the supply may be performed in a state where a tip end of the terminal enters the soldering tip from below such that the first solder piece is erected on the tip end of the terminal.

In the configuration described above, more specifically, the solder piece supply portion may cut the wire solder such that the second solder piece is shorter than the first solder piece.

In the configuration described above, more specifically, within the soldering tip, a reception portion which receives the supplied first solder piece may be provided, and the first solder piece may be erected on the reception portion. In the configuration described above, more specifically, the reception portion may be protruded inward from the inner wall of the soldering tip such that the inside diameter of the soldering tip is smaller than the outside diameter of the first solder piece.

In the configuration described above, more specifically, the solder piece supply portion may cut the wire solder such that the first solder piece is shorter than the second solder piece.

With the solder processing method according to the present invention, it is possible to more reliably heat and melt a solder piece in a posture where the solder piece is erected within a soldering tip.

Embodiments of the present invention will be described below using, as examples, first to third embodiments with reference to drawings. The details of the present invention are not limited at all to these embodiments.

<FIG> is a perspective view of a soldering device (one form of a solder processing device), <FIG> is a cross-sectional view taken along line II-II in the soldering device A shown in <FIG> and <FIG> is an exploded perspective view of part of a drive mechanism provided in the soldering device A shown in <FIG>. In <FIG>, parts of an enclosure and a support portion <NUM> are cut out, and thus the interior of the soldering device A is displayed.

As shown in <FIG>, the soldering device A is a device in which a wire solder W is supplied from above, and in which a soldering tip <NUM> provided in a lower portion is utilized so as to solder a wiring board Bd arranged below the soldering tip <NUM> and an electronic component Ep. The wire solder W has a structure in which a flux layer is provided within a tubular solder layer. Hence, a solder piece produced by cutting the wire solder W likewise has the structure in which the flux layer is provided within the tubular solder layer. The soldering device A includes the support portion <NUM>, a cutter unit <NUM>, the drive mechanism <NUM>, a heater unit <NUM>, the soldering tip <NUM> and a solder feed mechanism <NUM>. A combination of the heater unit <NUM> and the soldering tip <NUM> forms a soldering iron portion.

The support portion <NUM> includes a wall member <NUM> which is provided so as to stand and which is formed in the shape of a flat plate. In the following description, for convenience, it is assumed that as shown in <FIG>, a horizontal direction along the wall member <NUM> is an X direction, that a horizontal direction perpendicular to the wall member <NUM> is a Y direction and that a vertical direction along the wall member <NUM> is a Z direction. For example, as shown in <FIG>, the wall member <NUM> has a Z-X flat surface.

The soldering device A supplies molten solder to the wiring board Bd attached to a jig fixture Gj and a terminal P of the electronic component Ep arranged on the wiring board Bd, and thereby connects and fixes them. When soldering is performed, the jig fixture Gj is moved in the X direction and the Y direction so as to locate a land Ld on the wiring board Bd. Then, the soldering device A can be moved in the Z direction, and after the location, the soldering device A is moved in the Z direction, and thus it is possible to bring the tip end of the soldering tip <NUM> into contact with the land Ld.

The support portion <NUM> includes: a holding portion <NUM> which is provided in a position displaced upward from a lower end portion of the wall member <NUM> in the Z direction; a sliding guide <NUM> which is fixed to a side edge portion (lower portion) of the wall member <NUM> in the Z direction; and a heater unit fixing portion <NUM> which is provided at an end portion (lower end portion) of the wall member <NUM> in the Z direction.

The cutter unit <NUM> cuts the wire solder W fed by the solder feed mechanism <NUM> into a solder piece Wh which has a predetermined length. Although described in detail later, the soldering device A heats the soldering tip <NUM> in a state where a first solder piece Wh1 and a second solder piece Wh2 are supplied into the soldering tip <NUM>, and supplies the molten solder downward. In the following description, the first solder piece Wh1 and the second solder piece Wh2 are collectively referred to as the solder piece Wh.

The cutter unit <NUM> includes: a cutter lower blade <NUM> (fixed blade portion) which is fixed to the sliding guide <NUM>; a cutter upper blade <NUM> (movable blade portion) which is arranged in an upper portion of the cutter lower blade <NUM> and which is arranged so as to be able to slide in the X direction; and a pusher pin <NUM> (solder pushing portion) which is provided in the cutter upper blade <NUM> and which slides in a direction (Z direction) intersecting the direction of sliding of the cutter upper blade <NUM>. As shown in <FIG>, the movement of the cutter upper blade <NUM> in the Z direction is restricted by the sliding guide <NUM>, and the cutter upper blade <NUM> can slide in the X direction.

Here, the sliding guide <NUM> will be described in detail. The sliding guide <NUM> includes a pair of wall portions <NUM> which make contact with both ends of the cutter lower blade <NUM> in the Y direction, and the pair of wall portions <NUM> include stopper portions <NUM> which are protruded toward the other side. In the stopper portions <NUM>, tip ends are prevented from making contact with each other, and in other words, an opening is provided in an upper portion of the sliding guide <NUM>. The stopper portions <NUM> restrict the movement of the cutter upper blade <NUM> in the Z direction.

As shown in <FIG>, the cutter upper blade <NUM> includes an upper blade hole <NUM> that is a through hole into which the wire solder W fed by the solder feed mechanism <NUM> is inserted and a pin hole <NUM> that is a through hole into which the rod portion <NUM> of the pusher pin <NUM> is inserted. The side edge portion of the upper blade hole <NUM> at the lower end is formed in the shape of a cutting blade. The cutter lower blade <NUM> includes a lower blade hole <NUM> that is a through hole into which the wire solder W passing through the upper blade hole <NUM> is inserted. The side edge portion of the lower blade hole <NUM> at the upper end is formed in the shape of a cutting blade. In a state where the wire solder W is inserted into the upper blade hole <NUM> and the lower blade hole <NUM>, they are displaced in a direction intersecting the wire solder W, and thus the wire solder W is cut by the cutting blades thereof.

The pusher pin <NUM> is the solder pushing portion, and pushes downward the solder piece Wh which is left in the lower blade hole <NUM> after being cut by the cutter upper blade <NUM> and the cutter lower blade <NUM>. The pusher pin <NUM> includes: the rod portion <NUM> which is slidably supported in the pin hole <NUM>; a head portion <NUM> which is provided at the end portion of the rod portion <NUM>; and a spring <NUM> which is wound around the rod portion <NUM> and which is arranged between the head portion <NUM> and the cutter upper blade <NUM>. Furthermore, in the pusher pin <NUM>, at the end portion of the rod portion <NUM> on the side opposite to the head portion <NUM>, a stopper for reducing the removal of the rod portion <NUM> from the pin hole <NUM> is provided. The pusher pin <NUM> is constantly raised upward, that is, to the side opposite to the cutter lower blade <NUM> by the elastic force of the spring <NUM>.

As shown in <FIG> and <FIG>, the drive mechanism <NUM> includes: an air cylinder <NUM> which is held by the holding portion <NUM>; a piston rod <NUM> which passes through a through hole provided in the holding portion <NUM> and which is driven by the air cylinder <NUM> so as to slide in the Z direction; and a guide shaft <NUM> which is supported both by the holding portion <NUM> and the cutter lower blade <NUM>, which is extended in the Z direction and which is formed in the shape of a cylinder. The drive mechanism <NUM> further includes: a cam member <NUM> that is supported by the guide shaft <NUM> so as to be able to slide in the Z direction; and a slider portion <NUM> that includes a cam groove <NUM> with which a pin <NUM> provided in the cam member <NUM> and described later is engaged.

The air cylinder <NUM> drives the piston rod <NUM> such that the piston rod <NUM> slides (expands and contracts) by the pressure of air supplied from the outside, and the air cylinder <NUM> and the piston rod <NUM> form the actuator of the drive mechanism <NUM>. The piston rod <NUM> is provided parallel to the guide shaft <NUM>, and linearly reciprocates along the guide shaft <NUM>. A tip end portion of the piston rod <NUM> is fixed to the cam member <NUM>, and the cam member <NUM> slides in the Z direction by the expansion and contraction of the piston rod <NUM>. The sliding of the cam member <NUM> is guided by the guide shaft <NUM>.

As shown in <FIG>, a lower end portion of the guide shaft <NUM> is fitted into a concave hole provided in the cutter lower blade <NUM>, and the guide shaft <NUM> is screwed and fixed to the cutter lower blade <NUM> with a screw <NUM>. An upper portion of the guide shaft <NUM> passes through a hole provided in the holding portion <NUM>, and the movement thereof is restricted by a pin <NUM>. In other words, the guide shaft <NUM> is fixed with the screw <NUM> to the cutter lower blade <NUM> and is fixed with the pin <NUM> to the holding portion <NUM>.

As shown in <FIG> and <FIG>, the cam member <NUM> is a rectangular member, and includes: a concave portion <NUM> that is obtained by cutting out part of a long side into a rectangular shape; and a cylindrical support portion <NUM> that is coupled to the cam member <NUM> and that includes a through hole through which the guide shaft <NUM> passes. In the concave portion <NUM>, the slider portion <NUM> is arranged slidably (in the X direction and the Z direction). The support portion <NUM> is shaped so as to extend in a direction parallel to the pin <NUM>, and is provided so as to reduce the rattling of the cam member <NUM>. In other words, when the cam member <NUM> has a certain degree of thickness, and thus it is unlikely that rattling occurs, the cylindrical portion may be omitted such that only the through hole forms the support portion <NUM>.

The cam member <NUM> further includes: the cylindrical pin <NUM> which is provided in an intermediate portion of the concave portion <NUM> and whose center axis is perpendicular to the guide shaft <NUM>; a pin pushing portion <NUM> which is adjacent to the concave portion <NUM> and which pushes the pusher pin <NUM>; and a bearing <NUM> which is arranged within the support portion <NUM>. The pin <NUM> is inserted into the cam groove <NUM> which is provided in the slider portion <NUM> and which will be described later. The bearing <NUM> is a member which is externally fitted to the guide shaft <NUM> and which makes cam member <NUM> smoothly slide such that the cam member <NUM> is prevented from rattling.

As shown in <FIG> and <FIG>, the slider portion <NUM> is a member which is formed in the shape of a rectangular plate, and is formed integrally with the cutter upper blade <NUM>. The slider portion <NUM> includes the cam groove <NUM> which passes through the plate in the direction of thickness of the plate and which is extended in a longitudinal direction. The cam groove <NUM> includes a first groove portion <NUM> on the upper side which is extended parallel to the guide shaft <NUM> and a second groove portion <NUM> on the lower side which is extended parallel to the guide shaft <NUM>. The first groove portion <NUM> and the second groove portion <NUM> are provided so as to be displaced from each other in the X direction, and the cam groove <NUM> includes a connection groove portion <NUM> which connects the first groove portion <NUM> and the second groove portion <NUM>.

The pin <NUM> of the cam member <NUM> is inserted into the cam groove <NUM>, the cam member <NUM> is moved along the guide shaft <NUM> and thus the pin <NUM> slides on the inner surface of the cam groove <NUM>. When the pin <NUM> is located in the connection groove portion <NUM> of the cam groove <NUM>, the pin <NUM> pushes the inner surface of the connection groove portion <NUM>. In this way, the slider portion <NUM> and the cutter upper blade <NUM> formed integrally with the slider portion <NUM> are moved (slide with respect to the cutter lower blade <NUM>) in a direction (X direction) intersecting the direction of sliding of the cam member <NUM> (Z direction).

As shown in <FIG>, the heater unit <NUM> is a heating device for heating and melting the solder piece Wh, and is fixed to the heater unit fixing portion <NUM> provided in a lower end portion of the wall member <NUM>. The heater unit <NUM> includes a heater <NUM> which generates heat by passing electricity and a heater block <NUM> for attaching the heater <NUM>. The heater <NUM> is wound around the outer circumferential surface of the cylindrical heater block <NUM>.

The heater block <NUM> has a cylindrical shape, and includes: a concave portion <NUM> which is used for attaching the soldering tip <NUM> to an end portion in the axial direction and whose cross section is circular; and a solder supply hole <NUM> which passes through from the center portion of a bottom portion of the concave portion <NUM> to the opposite side. The heater block <NUM> is provided in contact with the cutter lower blade <NUM> such that the solder supply hole <NUM> and the lower blade hole <NUM> communicate with each other. The heater block <NUM> is provided as described above, and thus the solder piece Wh is moved from the lower blade hole <NUM> to the solder supply hole <NUM>.

The soldering tip <NUM> is a member which is formed in the shape of a cylinder extended in an up/down direction and which can be heated, and includes a solder hole <NUM> in a center portion which is extended in the axial direction. The soldering tip <NUM> is inserted into the concave portion <NUM> and is prevented from being removed with an unillustrated member. The solder hole <NUM> of the soldering tip <NUM> communicates with the solder supply hole <NUM> of the heater block <NUM>, and the solder piece Wh is fed from the solder supply hole <NUM>.

The heat from the heater <NUM> is transmitted to the soldering tip <NUM>, and the solder piece Wh is melted by the heat. Hence, the soldering tip <NUM> is formed of a material having a high thermal conductivity, for example, a ceramic such as a silicon carbide or an aluminum nitride or a metal such as tungsten. Although in the soldering device A, the soldering tip <NUM> is formed in the shape of a cylinder, there is no limitation to this configuration, and the soldering tip <NUM> which is formed in the shape of a tube whose cross section is polygonal or oval may be used. The soldering tip <NUM> may be prepared that has a different shape according to the wiring board Bd and (or) the shape of the terminal P of the electronic component Ep on which soldering is performed.

As shown in <FIG> and <FIG>, the solder feed mechanism <NUM> supplies the wire solder W, and includes a pair of feed rollers 61a and 61b which feed the wire solder W and a guide tube <NUM> which guides the fed wire solder W to the upper blade hole <NUM> of the cutter upper blade <NUM>. The pair of feed rollers 61a and 61b are attached to the support portion <NUM>, sandwich the wire solder W and are rotated so as to feed the wire solder W downward. The guide tube <NUM> is a tubular member which can be elastically deformed, and the upper end thereof is arranged close to a portion of the feed rollers <NUM> from which the wire solder W is fed.

The lower end of the guide tube <NUM> is provided so as to communicate with the upper blade hole <NUM> of the cutter upper blade <NUM>. The lower end of the guide tube <NUM> is moved so as to follow the sliding of the cutter upper blade <NUM>, and the guide tube <NUM> is provided so as not to be excessively pulled or stick in the range of the sliding of the cutter upper blade <NUM>. The length of the wire solder fed is determined by the rotation angles (the numbers of revolutions) of the individual feed rollers 61a and 61b.

When the soldering is performed with the soldering device A, the tip end of the soldering tip <NUM> is brought into contact with the land Ld of the wiring board Bd on which the soldering is performed, and the land Ld and the terminal P of the electronic component Ep are surrounded by the soldering tip <NUM>. Here, the heat from the heater <NUM> is transmitted to the soldering tip <NUM>, and the soldering tip <NUM> is brought into contact with the land Ld and the terminal P of the electronic component Ep such that they are heated (preheated) to a temperature suitable for the soldering.

The operation of the soldering device A will then be described. As shown in <FIG>, immediately before the soldering is performed, the soldering device A is in a state where the piston rod <NUM> is stored within the air cylinder <NUM>, and the cam member <NUM> is in an upper portion (the uppermost portion of the range of the sliding) in the Z direction. Here, the pin <NUM> is located within the first groove portion <NUM> of the cam groove <NUM>, and the cutter upper blade <NUM> is located in a position closest to the guide shaft <NUM>. This position is assumed to be the initial position. The cutter upper blade <NUM> and the cutter lower blade <NUM> are formed such that when the soldering device A is in the initial position, the upper blade hole <NUM> and the lower blade hole <NUM> are overlaid on each other in the Z direction.

Then, the feed rollers 61a and 61b are driven to rotate so as to feed the wire solder W. Since the upper blade hole <NUM> and the lower blade hole <NUM> are in a state where they communicate with each other, the tip end of the wire solder W is moved into the lower blade hole <NUM>. The rotation angles of the feed rollers 61a and 61b are adjusted such that the length of the wire solder W entering the lower blade hole <NUM> is the length of the first solder piece Wh1.

In one round of the soldering, an amount of solder obtained by adding the amount of first solder piece Wh1 and the amount of second solder piece Wh2 is used. With consideration given to this fact, the lengths of the first solder piece Wh1 and the second solder piece Wh2 are determined according to, for example, the sizes of the land Ld and the terminal P of the electronic component Ep on which the soldering is performed. In the present embodiment, the length of the first solder piece Wh1 is set equal to the length of the second solder piece Wh2, and each of the amounts of solder pieces Wh1 and Wh2 is set to the half of the amount of solder necessary for one round of the soldering.

Then, the piston rod <NUM> is protruded from the air cylinder <NUM>, and thus the cam member <NUM> is moved downward along the guide shaft <NUM>. Since the pin <NUM> is arranged within the cam groove <NUM>, the pin <NUM> slides within the cam axis <NUM>. When the pin <NUM> is in the first groove portion <NUM>, since the first groove portion <NUM> coincides with the direction of movement of the pin <NUM> (the axial direction of the guide shaft <NUM>), the slider portion <NUM> does not receive a force from the cam member <NUM>, and thus the cam member <NUM> is stationary. Then, when the pin <NUM> reaches the connection groove portion <NUM> from the first groove portion <NUM>, the pin <NUM> pushes the inner surface of the connection groove portion <NUM>. In this way, a force in the X direction is applied to the slider portion <NUM>, and thus the slider portion <NUM> and the cutter upper blade <NUM> formed integrally with the slider portion <NUM> are moved (slide) in the X direction.

The cutter upper blade <NUM> slides such that the upper blade hole <NUM> and the lower blade hole <NUM> are displaced in the X direction, and thus the cutting blade formed in the edge of the end portion of the upper blade hole <NUM> intersects the cutting blade formed in the edge of the end portion of the lower blade hole <NUM>. Consequently, the wire solder W is cut, and thus the first solder piece Wh1 is first produced.

When the piston rod <NUM> is further protruded, the cam member <NUM> is further moved downward, and thus the pin <NUM> is moved from the connection groove portion <NUM> to the second groove portion <NUM>. Since the second groove portion <NUM> is also extended parallel to the guide shaft <NUM>, even when the cam member <NUM> is moved downward along the guide shaft <NUM>, the pin <NUM> does not push the slider portion <NUM>. In other words, although the cam member <NUM> is moved, the cutter upper blade <NUM> and the slider portion <NUM> are stopped. The cutter upper blade <NUM> is located in a position farthest from the guide shaft <NUM>. The cutter upper blade <NUM> and the cutter lower blade <NUM> are formed such that when the cutter upper blade <NUM> is in this position, the pin hole <NUM> is overlaid on the lower blade hole <NUM> in the Z direction.

When the piston rod <NUM> is much further protruded, the cam member <NUM> slides downward, and thus the pin pushing portion <NUM> of the cam member <NUM> pushes the head portion <NUM> of the pusher pin <NUM>. In this way, the rod portion <NUM> of the pusher pin <NUM> is inserted into the lower blade hole <NUM>. Here, the first solder piece Wh1 which is left in the lower blade hole <NUM> is pushed by the rod portion <NUM> so as to be moved toward the soldering tip <NUM>. Although the first solder piece Wh1 may be moved downward by its weight at the time of cutting, by the utilization of the pusher pin <NUM>, the first solder piece Wh1 can be reliably supplied into the solder hole <NUM> of the soldering tip <NUM>.

As shown in <FIG>, the first solder piece Wh1 supplied into the solder hole <NUM> is held in a state where the first solder piece Wh1 is erected within the soldering tip <NUM> so as to sit on the terminal P of the electronic component Ep. Furthermore, in the soldering device A, as in the case of the first solder piece Wh1, the wire solder W is cut again, and thus the second solder piece Wh2 is produced at this time. The second solder piece Wh2 is also supplied into the solder hole <NUM> of the soldering tip <NUM> by the utilization of the pusher pin <NUM> (or by its weight).

Consequently, as shown in <FIG>, within the soldering tip <NUM>, the solder pieces Wh1 and Wh2 are in a state where they are erected such that the second solder piece Wh2 sits on the first solder piece Wh1. As described above, the soldering device A supplies the first solder piece Wh1 and the second solder piece Wh2 in this order from above into the soldering tip <NUM>. The inside diameter of the soldering tip <NUM> is set so as to be slightly larger than the outside diameter of each of the solder pieces Wh1 and Wh2. Hence, even when the solder pieces Wh1 and Wh2 are inclined within the soldering tip <NUM>, they are supported by the inner wall thereof so as to be erected within the soldering tip <NUM> without fail.

The heat from the heater <NUM> is transmitted to the soldering tip <NUM>, and the first solder piece Wh1 and the second solder piece Wh2 are heated by the heat. Here, as shown in <FIG>, the flux <NUM> which flows out from the lower end portion of the second solder piece Wh2 flows between the first solder piece Wh1 and the inner wall surface of the soldering tip <NUM>. The flux <NUM> has, for example, as a main component, a rosin which is melted at about <NUM>. It is known that the thermal conductivity of a rosin is sufficiently (about <NUM> times) larger than that of air.

Since the flux <NUM> flowing therebetween serves as a heat medium (which makes it easy to transmit the heat from the soldering tip <NUM> to the first solder piece Wh1), as compared with a case where the flux <NUM> does not flow therebetween, the first solder piece Wh1 is melted rapidly and reliably. The flux <NUM> has a lower melting point than the solder and according to the invention the second solder piece Wh2 is closer to the heater unit <NUM> than the first solder piece Wh1 and thus the flux <NUM> flows out from the second solder piece Wh2 in a relatively early stage. Even when the flux <NUM> of the second solder piece Wh2 flows out from the upper end portion of the second solder piece Wh2 or from the upper end portion and the lower end portion thereof, the flux <NUM> likewise serves as the heat medium, and thus the first solder piece Wh1 is melted rapidly and reliably. However, it is likely that when the flux <NUM> flows out from the upper end portion of the second solder piece Wh2, the second solder piece Wh2 is melted earlier than the first solder piece Wh1, the molten second solder piece Wh2 flows between the first solder piece Wh1 and the inner wall surface of the soldering tip <NUM> and this serves as the heat medium, with the result that the melting of the first solder piece Wh1 is promoted. Through the process described above, finally, both the first solder piece Wh1 and the second solder piece Wh2 are completely heated and melted so as to be supplied onto the wiring board Bd arranged below.

Since the soldering tip <NUM> surrounds the land Ld of the wiring board Bd and the terminal P of the electronic component Ep, the molten solder flows to the land Ld and the terminal P of the electronic component Ep arranged below. Then, the soldering device A is moved in the Z direction, and thus the soldering tip <NUM> is moved away from the land Ld. In this way, the solder is cooled by outside air so as to be solidified, and thus the land Ld and the terminal P of the electronic component Ep are soldered.

Then, when the soldering is completed, the air cylinder <NUM> stores the piston rod <NUM> thereinto. In this way, the cam member <NUM> is moved upward in the Z direction, and the pusher pin <NUM> is pushed upward by the elastic force of the spring <NUM>. The rod portion <NUM> is removed from the lower blade hole <NUM>. Even if the cutter upper blade <NUM> slides in this state, the pusher pin <NUM> is not broken. Then, the pin <NUM> of the cam member <NUM> reaches the connection groove portion <NUM> of the cam groove <NUM>, and the slider portion <NUM> and the cutter upper blade <NUM> slide so as to approach the guide shaft <NUM>. When the pin <NUM> reaches the first groove portion <NUM> of the cam groove <NUM>, the soldering device A is returned to the initial position.

The second embodiment will then be described. The second embodiment is basically the same as the first embodiment except for the lengths of the solder pieces. In the following description, emphasis is placed on the description of portions which differ from those in the first embodiment, and the description of the common portions may be omitted.

The soldering device A of the second embodiment cuts the wire solder W such that the second solder piece Wh2 is shorter than the first solder piece Wh1. Specifically, in the present embodiment, the wire solder W is fed out by the solder feed mechanism <NUM> such that the second solder piece Wh2 is shorter than the first solder piece Wh1, and the wire solder W fed out is cut by the cutter unit <NUM>. The total of the amount of first solder piece Wh1 and the amount of second solder piece Wh2 is adjusted such that the total is the amount of solder necessary for one round of the soldering.

<FIG> shows a state where the first solder piece Wh1 is first supplied into the soldering tip <NUM> so as to sit on the terminal P of the electronic component Ep. <FIG> shows a state where the second solder piece Wh2 is further supplied so as to sit on the first solder piece Wh1. <FIG> shows a state where in the state shown in <FIG>, a certain amount of time has elapsed such that the flux <NUM> flows out from the second solder piece Wh2.

As shown in <FIG>, in the present embodiment, the second solder piece Wh2 is shorter than the first solder piece Wh1, and within the soldering tip <NUM>, these solder pieces are erected such that the second solder piece Wh2 sits on the first solder piece Wh1. Even in the present embodiment, the inside diameter of the soldering tip <NUM> is set so as to be slightly larger than the outside diameter of each of the solder pieces Wh1 and Wh2. Hence, even when the solder pieces Wh1 and Wh2 are inclined within the soldering tip <NUM>, they are supported by the inner wall thereof so as to be erected within the soldering tip <NUM> without fail.

Furthermore, in the present embodiment, the second solder piece Wh2 is shorter than the first solder piece Wh1, and accordingly, the heat capacity is relatively low. Hence, in the present embodiment, as compared with the first embodiment, the second solder piece Wh2 is easily increased in temperature, and thus as shown in <FIG>, the flux <NUM> flows out from the second solder piece Wh2 in an earlier stage.

In this way, in the present embodiment, the first solder piece Wh1 can be melted more rapidly and reliably. The temperature increase of the second solder piece Wh2 is sped up as the second solder piece Wh2 is produced so as to be shorter (as the heat capacity is decreased). With respect to the specific lengths of the solder pieces, for example, the length of the first solder piece Wh1 is set to <NUM>, the length of the second solder piece Wh2 is set to <NUM> and thus it is possible to sufficiently obtain the effects of the present invention.

In terms of enhancing the efficiency of heating of the solder piece, the difference between the inside diameter of the soldering tip <NUM> and the outside diameter of the solder piece is preferably minimized. However, an appropriate clearance is preferably provided between the soldering tip <NUM> and the solder piece so that the supply of the solder piece into the soldering tip <NUM> is not prevented by burrs resulting from the cutting of the solder piece or the deformation of the solder piece. In the present embodiment, with consideration given to what has been described above, the inside diameter of the soldering tip <NUM> is set within a range of <NUM> to <NUM>, the outside diameter of the solder piece is set within a range of <NUM> to <NUM> and the difference between the inside diameter and the outside diameter is set within a range of <NUM> to <NUM>.

The third embodiment will then be described. The third embodiment is basically the same as the first embodiment except for the lengths of the solder pieces and the internal shape of the soldering tip. In the following description, emphasis is placed on the description of portions which differ from those in the first embodiment, and the description of the common portions may be omitted.

The soldering device A of the third embodiment cuts the wire solder W such that the first solder piece Wh1 is shorter than the second solder piece Wh2. Specifically, in the present embodiment, the wire solder W is fed out by the solder feed mechanism <NUM> such that the first solder piece Wh1 is shorter than the second solder piece Wh2, and the wire solder W fed out is cut by the cutter unit <NUM>. The total of the amount of first solder piece Wh1 and the amount of second solder piece Wh2 is adjusted such that the total is the amount of solder necessary for one round of the soldering.

<FIG> shows a state where the first solder piece Wh1 is supplied into the soldering tip <NUM>. As shown in the figure, in the third embodiment, within the soldering tip <NUM>, a reception portion which receives the supplied first solder piece Wh1 is provided. More specifically, the reception portion is a step <NUM> which is protruded inward from the inner walls of the soldering tip <NUM> such that the inside diameter of the soldering tip <NUM> is less than the outside diameter of the first solder piece Wh1. The inside diameter of the soldering tip <NUM> is slightly larger than the outside diameter of the first solder piece Wh1 on the upper side with respect to the step <NUM> whereas the inside diameter of the soldering tip <NUM> is slightly smaller than the outside diameter of the first solder piece Wh1 on the lower side with respect to the step <NUM>.

The step <NUM> within the soldering tip <NUM> is provided in a position on the upper side with respect to the tip end of the terminal P of the electronic component Ep. Hence, when the first solder piece Wh1 is supplied into the soldering tip <NUM>, as shown in <FIG>, the first solder piece Wh1 is caught on the step <NUM> within the soldering tip <NUM> before reaching the terminal P, and thus the first solder piece Wh1 can be brought into a state where the first solder piece Wh1 is erected on the step <NUM> (reception portion).

<FIG> shows a state where in the state of <FIG>, the second solder piece Wh2 is further supplied. As shown in <FIG>, in the present embodiment, the first solder piece Wh1 is shorter than the second solder piece Wh2, and within the soldering tip <NUM>, the solder pieces are erected such that the second solder piece Wh2 sits on the first solder piece Wh1. The inside diameter of the soldering tip <NUM> on the upper side with respect to the step <NUM> is set so as to be slightly larger than the outside diameter of each of the solder pieces Wh1 and Wh2. Hence, even when the solder pieces Wh1 and Wh2 are inclined within the soldering tip <NUM>, they are supported by the inner wall thereof so as to be erected within the soldering tip <NUM> without fail.

Furthermore, the first solder piece Wh1 in the present embodiment is supplied into the soldering tip <NUM> earlier than the second solder piece Wh2, and the first solder piece Wh1 is shorter than the second solder piece Wh2, and accordingly, the heat capacity is relatively low. Thus, in the present embodiment, the first solder piece Wh1 is increased in temperature more easily than the second solder piece Wh2.

Claim 1:
A solder processing method,
wherein a plurality of solder pieces (Wh1, Wh2) are sequentially supplied into a substantially tubular soldering tip (<NUM>) that is extended vertically, the solder pieces (Wh1, Wh2) having a structure in which a layer of a flux is provided within a tubular solder layer, heat from a heater (<NUM>) of a heater unit (<NUM>) is transmitted to the soldering tip (<NUM>) and melts the solder pieces (Wh1, Wh2),
within the soldering tip (<NUM>), the solder pieces (Wh1, Wh2) are erected such that the second solder piece (Wh2), which is subsequently supplied, sits on the first solder piece (Wh1), which is first supplied,
the second solder piece (Wh2) is closer to the heater unit (<NUM>) than the first solder piece (Wh1), and
the solder pieces (Wh1, Wh2) are melted such that the molten solder is supplied downward.