JP2017011082A - Reflow furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reflow furnace capable of appropriately soldering electronic components to a substrate even if electronic component with different thermal capacities are packaged on the substrate.SOLUTION: A reflow furnace 100 comprises: a hot wind generation part 20 and a conveyance part 30; a partition plate 40 separating the hot wind generation part 20 and the conveyance part 30; a plurality of hot wind emission parts 42 formed on the partition plate 40; an additional heater 44 provided in the hot wind emission part 42; a substrate passage detection part 34 for detecting the passage of a substrate 60; a storage part 80 storing a conveyance speed of conveyance means 32 and a packaging position of an electronic component 62A subjected to high-temperature heating on the substrate 60; and an operation control part 70 for heating the high-temperature heating target electronic component 62A with additional heating hot winds by heating the additional heaters 44 in predetermined timing based on passage timing of the substrate 60 detected by the substrate passage detection part 34, the conveyance speed and the packaging position of the electronic component 62A subjected to high-temperature heating on the substrate 60.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a reflow furnace, and more particularly, to a reflow furnace capable of appropriately soldering each electronic component to a substrate even on a substrate on which a plurality of electronic components having different heat capacities are mounted.

A reflow furnace for soldering electronic components to the board by blowing hot air on the board on which the solder and electronic components are mounted, reflowing the solder, and then cooling is widely used in the manufacturing site of electronic component mounting boards, etc. It has been.
In such a reflow furnace, as described in Patent Document 1, it is possible to appropriately solder each electronic component to the substrate even if the substrate is mounted with a plurality of electronic components having different heat capacities. Possible reflow furnace configurations have also been proposed.

JP-A-8-181427

  The configuration of the reflow furnace described in Patent Document 1 is that soldering between a substrate and an electronic component is performed by intensively applying thermal energy to a portion where an electronic component having a large heat capacity is mounted on the substrate. In this case, a configuration is adopted in which the transport of the substrate is stopped each time. Thus, in the reflow furnace that stops the conveyance of the substrate, there is a natural limit in improving the efficiency of the soldering operation of the electronic component to the substrate. Further, in the configuration disclosed in Patent Document 1, sufficient heating can be performed for an electronic component having a large heat capacity, but positive heating should not be performed for an electronic component having a small heat capacity. Although not provided, there is a risk that the electronic component may be heated more than necessary, and the reliability of the electronic component after reflow is inferior.

  Therefore, the present invention minimizes heating of an electronic component having a small heat capacity to a substrate mounted in a state where an electronic component having a large heat capacity and an electronic component having a small heat capacity are mixed, and the electronic component having a large heat capacity. For this, a configuration that can perform sufficient heating as necessary for reflowing the solder was adopted. Accordingly, it is an object of the present invention to provide a reflow furnace capable of reliably performing soldering with a substrate in each electronic component having a different heat capacity regardless of the heat capacity of the electronic component.

As a result of intensive studies by the inventor of the present application in order to solve the above problems, the following configuration has been conceived.
That is, the present invention includes a hot air generating unit in which a main heater and a fan are disposed, a transport unit in which a substrate on which electronic components are mounted is transported by a transport unit, and between the hot air generating unit and the transport unit. A partition plate, a plurality of hot air ejection portions formed on the partition plate, an additional heater provided in at least one of the hot air ejection portions, and the transport unit, and transported by the transport means A board passage detection unit for detecting the passage of the board, a transport speed of the transport means, and mounting of a high-temperature heating target electronic component to be heated at a higher temperature than the other electronic components among the electronic components on the substrate A storage unit in which the position is stored in advance; the substrate passage timing detected by the substrate passage detection unit; the transport speed stored in the storage unit; Based on the mounting position on the substrate, the additional heater is heated at a predetermined timing so that the high-temperature heating target electronic component is heated by the additional heating hot air that is higher in temperature than the hot air generated by the hot air generation unit. An operation control unit for controlling operation is provided.

  As a result, even when multiple electronic components with different heat capacities are mounted on the substrate in a mixed state, it is added to the high-temperature heating target electronic component that is an electronic component with a large heat capacity without stopping the conveying means. Since heated hot air can be intensively sprayed, it is possible to reliably solder each electronic component and substrate with different heat capacities without excessive heating to electronic components that are not subject to high-temperature heating, which are electronic components with small heat capacities. Can be attached.

  Moreover, it is preferable that the said additional heater has the cylindrical body standingly arranged in the opening part by the side of the hot air generation part of the said hot air ejection part, and the heat source accommodated in the said cylindrical body.

  Thereby, since an additional heater only needs to additionally heat only the heated hot air in the internal space of the cylindrical body, it can be a reflow furnace that reliably generates additional heated hot air in a short time.

  Moreover, it is preferable that the said cylinder is formed with the heat insulation material.

  According to this, additional heating is not performed on the electronic components that are not subject to high-temperature heating, without heating the heated hot air blown out from the hot air blowing portion where no additional heater is disposed into the internal space of the transport unit by the additional heater. There is no fear of blowing hot air, and the reliability of the electronic component subject to high-temperature heating can be improved.

  The heat source is preferably formed by a heating wire having a spiral shape.

  Thereby, since the additional heating hot air supplied from the additional heater can be supplied into the conveying portion in a spiral flow, the high-temperature heating target electronic component can be efficiently heated.

  According to the reflow furnace according to the present invention, the high-temperature heating target electronic component having a large heat capacity and the non-high-temperature heating target electronic component having a small heat capacity are disposed in the transfer unit with respect to the substrate mounted in a mixed state. Necessary by additional heaters for high-temperature heating target electronic components by selectively operating multiple additional heaters based on the substrate passage timing by the substrate passage detection unit and the conveyance speed previously stored in the storage unit And soldering the electronic component to be heated to the board while maintaining the reliability of the electronic component not to be heated at high temperature. Can be performed reliably.

It is a front view which shows schematic structure of the reflow furnace in this embodiment. It is explanatory drawing which shows schematic structure of the unit furnace in a reflow part among the reflow furnaces shown in FIG. It is explanatory drawing which shows schematic structure of the additional heater in FIG.

Hereinafter, the reflow furnace in this embodiment is demonstrated in detail based on drawing.
As shown in FIG. 1, the reflow furnace 100 in this embodiment is configured by arranging a plurality of unit furnaces 10 in series. The reflow furnace 100 includes a preheat part PH that heats the electronic component 62 carried into the reflow furnace 100 and a substrate 60 on which solder (not shown) is mounted to a predetermined temperature, and an electron that is heated to a predetermined temperature in the preheat part PH. The reflow unit RF further heats the component 62 and the substrate 60 on which the solder is mounted to the solder melting temperature, and the cooling unit CL gradually cools the substrate 60 to which the electronic component 62 is soldered by the reflow unit RF. Yes. In such heat treatment, the operation control unit 70 performs operation control based on a temperature profile stored in the storage unit 80 in advance.

  Each of these preheating part PH and reflow part RF is comprised by the unit furnace 10 as shown in FIG. Further, the cooling section CL in the present embodiment is the same as that of the unit furnace 10 shown in FIG. 2 except for the main heater 22 and the additional heater 44. However, the cooling part CL is added to the main heater 22 of the unit furnace 10 shown in FIG. The heater 44 can be used without being operated.

  The unit furnace 10 will be described in detail. As shown in FIG. 2, the unit furnace 10 includes a hot air generator 20 that is provided with a main heater 22 and a fan 24 and generates hot air, and a transfer unit 30 that is provided with a transfer means 32 and a substrate passage detection unit 34. The hot air blowing portion 42 and the additional heater 44 are partitioned vertically by the partition plates 40 disposed at a plurality of locations, and the outer surfaces of the hot air generating portion 20 and the conveying portion 30 are covered with the hood 50. Is formed by.

  A known configuration can be adopted for the main heater 22 in the hot air generating unit 20. Further, nitrogen gas from a nitrogen gas tank (not shown) is constantly supplied to the fan 24 in the present embodiment. A gas flow passage (not shown) extending in the direction of the rotation axis is formed on the rotation shaft of the motor M that is the drive source of the fan 24, and from a gas ejection portion formed on the tip end side of the rotation shaft of the fan 24. Nitrogen gas is supplied into the reflow furnace 100 (unit furnace 10). As described above, the reflow furnace 100 in the present embodiment adopts a configuration in which the in-furnace gas is purged of air as much as possible, but an inert gas typified by nitrogen gas is not injected into the furnace. You can also.

  An endless circulation type conveying means 32 typified by a mesh conveyor formed of a heat resistant member is disposed in the conveying unit 30. The transport means 32 transports the substrate 60 at a preset speed from the inlet side 102 to the outlet side 104 of the reflow furnace 100 (in the direction of arrow X in FIG. 1). The transport unit 30 is provided with a substrate passage detection unit 34 for detecting the passage timing of the substrate 60 transported by the transport means 32. When the substrate passage detection unit 34 detects the passage of the substrate 60 at a predetermined position of the transport unit 30, the substrate passage detection unit 34 transmits a detection signal (substrate passage timing) to the operation control unit 70 described later.

  The hot air generating unit 20 and the conveying unit 30 are partitioned up and down by a partition plate 40. In the partition plate 40, through holes for ejecting hot air generated by the hot air generating unit 20 to the transport unit 30 are arranged in a matrix form as hot air ejecting portions 42. As described above, an additional heater 44 is attached to at least one of the hot-air ejection portions 42 formed in the partition plate 40. In the present embodiment, as shown in FIG. 2, the embodiment in which the additional heater 44 is selectively attached to the hot air ejection portion 42 has been described. However, the additional heater 44 is attached to all the hot air ejection portions 42. It may be attached.

  As shown in FIG. 3, the additional heater 44 in the present embodiment includes a cylindrical body 44 </ b> A that is erected in the hot air generating section side opening of the hot air ejection section 42, and a heat source that is accommodated in the internal space of the cylindrical body 44 </ b> A. As a heating wire 44B. Here, a cylindrical tubular body 44A and a heating wire 44B formed in a spiral shape are used. By adopting such a configuration of the additional heater 44, a part of the hot air in the hot air generating unit 20 is additionally heated, and the additional heated hot air blown out from the hot air blowing unit 42 to the transport unit 30 is made into a spiral flow. be able to.

  In addition, if the planar position of the lower end of the heating wire 44B is aligned with the planar position of the hot air ejection part 42, the additional heating hot air can be ejected to the transport unit 30 with a smoother spiral flow. Convenient. By jetting such additional heated hot air to the transport unit 30 by a spiral flow, the electronic component 62 and the solder mounted on the substrate 60 transported in the transport unit 30 can be heated to a predetermined temperature in a short time. It becomes possible. Further, if the cylindrical body 44A is formed of a heat insulating material, it is possible to prevent the additional air from being heated by the additional heater 44 from the hot air ejected from the hot air ejection section 42 where the additional heater 44 is not disposed. it can.

  The operation control unit 70 is configured by an operation control program 72 in which operation commands for respective elements constituting the reflow furnace 100 are defined in advance, and a CPU 74 that executes each operation command based on the operation control program 72. The operation control program 72 can be stored in advance in a state that can be read by the CPU 74 in a storage unit 80 represented by a recording medium, a non-volatile storage unit of the reflow furnace 100, or the like. Such an operation control program 72 can be the same as the operation control program in a known reflow furnace, but in this embodiment, the transfer speed of the transfer means 32 and the additional heater 44 and the substrate passage detection unit 34 are used. It has a feature in the contents of the operation command for the part associated with the passage timing of the substrate 60.

  Specifically, thermal output data in which the output of the main heater 22 and the output of the additional heater 44 are recorded, transport speed data in which the transport speed of the transport means 32 is recorded, and electronic components mounted on the substrate 60 Based on the heat capacity in each of 62 and the heat capacity distribution data on the board in which the position on the board 60 is recorded, the operation command of the heating process in the reflow unit RF for the board 60 on which the electronic component 62 and the solder are mounted is specified. It has been done.

  First, when the CPU 74 receives a substrate passage detection signal (passage timing of the substrate 60 at a predetermined position of the transport unit 30) from the substrate passage detection unit 34, the electronic component 62 is based on the transport speed data and the heat capacity distribution data on the substrate. And the mounting position of the high-temperature heating target electronic component 62A (hereinafter, referred to as the high-temperature heating target position), which is an electronic component having a large heat capacity, on the board 60 on which the solder is mounted, the time until the position immediately below the predetermined additional heater 44 is reached. calculate.

  Next, the CPU 74 activates the additional heater 44 in accordance with the timing at which the high temperature heating target position reaches a position directly below the additional heater 44, and additionally heats the hot air generated by the hot air generation unit 20. Since the additional heaters 44 are disposed at a plurality of locations along the transport direction of the substrate 60, the additional heating process using only the additional heaters 44 at a specific location does not occur. There is no need to change. This is advantageous in that the reflow processing capacity between the substrate 60 and the electronic component in the reflow furnace 100 does not decrease.

  In addition, since the additional heaters 44 in the present embodiment are arranged for the plurality of hot-air ejection portions 42, the CPU 74 is arranged at a position corresponding to the high-temperature heating target position as shown by the thick arrow in FIG. Only the added additional heater 44 can be activated. As a result, the portion (non-high-temperature heating target position) where the high-temperature heating non-electronic component 62B, which is an electronic component having a small heat capacity, is mounted is hardly affected by the additional heating by the heated hot air. Thus, an appropriate reflow process can be performed without losing the reliability of the electronic component 62B not to be heated.

When reflow processing is performed on a substrate 60 having a different planar position on which the electronic component 62 is mounted using the same reflow furnace 100, the other heat capacity distribution data on the substrate corresponding to the substrate 60 on which reflow processing is performed is stored in the storage unit. If the CPU 74 reads the heat capacity distribution data on another board and stores it on the board 74, the additional heater 44 corresponding to the mounting state of the electronic component 62 on the board 60 to be reflowed can be operated as appropriate. A furnace 100 can be used.
If a plurality of types of heat capacity distribution data on the substrate are stored in the storage unit in advance, the operation control unit 70 displays the heat capacity distribution data on the substrate that can be used by the operator on the display device 90 provided in the reflow furnace 100. Displaying the list, appropriately selecting the heat capacity distribution data on the substrate corresponding to the substrate 60 to be reflowed, and executing the reflow processing of the electronic component 62 and the substrate 60 based on the heat capacity distribution data on the substrate selected by the operator You can also.

  As another embodiment, the substrate passage detection unit 34 is arranged in the transport unit 30 in accordance with the arrangement position of the additional heater 44, and the additional heater 44 and the substrate passage detection unit 34 are linked to each other. it can. By adopting such a configuration, when the CPU 74 receives a substrate passage detection signal (passage timing of the substrate 60 at a predetermined position of the transport unit 30) from a certain substrate passage detection unit 34, the CPU 74 outputs the substrate passage detection signal. Since the additional heaters 44 associated with the received board passage detection unit 34 may be sequentially operated as indicated by the thick arrows in FIG. 2, the information processing amount by the CPU 74 can be reduced, and the operation control unit 70 can be simplified.

  Further, not only one-to-one association of the additional heaters 44 and the substrate passage detection unit 34 but also a configuration in which a plurality of additional heaters 44 are associated with one substrate passage detection unit 34 can be employed. . In this case, the operation timing of each additional heater 44 may be determined based on the conveyance speed of the conveyance means 32 and the plane separation distance between the substrate passage detection unit 34 and the additional heater 44.

  As mentioned above, although the structure of the reflow furnace 100 concerning this invention was demonstrated in detail using embodiment and the modification, this invention is not limited to the above embodiment and modification, and the summary of invention. If it is the range which does not change, it can also modify | change suitably. For example, in the present embodiment, an example in which the endless circulation type conveying means 32 that circulates from the inlet side 102 to the outlet side 104 of the reflow furnace 100 is described. However, the conveying means 32 is a unit furnace. 10 may be of an endless circulation type.

  According to this structure, since the conveyance speed of the board | substrate 60 can be changed according to the unit furnace 10, when performing the additional heating of the hot air by the additional heater 44, the conveyance speed of the board | substrate 60 is reduced, and cooling part CL By increasing the transfer speed at, sufficient time can be taken for the additional heat treatment of the hot air by the additional heater 44 without reducing the transfer speed as a total of the reflow furnace 100. In other words, the heating capacity of the additional heater 44 can be reduced, and the power consumption of the reflow furnace 100 can be reduced.

  Moreover, in the above embodiment, although the structure of the additional heater 44 demonstrated the form which accommodated the helical heating wire 44B in the cylindrical cylindrical body 44A, it is not limited to this form. . A screw having a cylindrical tubular body 44A, an axis disposed at the center of the plane of the cylindrical tubular body 44A, and a spiral plate formed around the axis is disposed, and an electric power is supplied to the axis or the spiral plate. An additional heater 44 formed by embedding a heat ray may be used.

  This configuration is advantageous in that the spiral flow of the additional heated hot air blown from the additional heater 44 to the transport unit 30 can be further ensured. On the contrary, if the configuration of the additional heater 44 in which the linear heating wire 44B is accommodated in the cylindrical body 44A including the cylindrical body is adopted, the additional heating hot air blown from the additional heater 44 to the transport unit 30 is linearly generated. It can also be done.

  Moreover, the structure which combined the description content in this embodiment suitably can also be employ | adopted.

10 unit furnace,
20 hot air generator, 22 main heater, 24 fans,
30 transport section, 32 transport means, 34 substrate passage detection section,
40 partition plate, 42 hot air jetting part,
44 additional heater, 44A cylindrical body, 44B heating wire,
50 hoods, 60 substrates,
62 electronic components, 62A electronic components subject to high-temperature heating, 62B electronic components not subject to high-temperature heating,
70 operation control unit, 72 operation control program, 74 CPU,
80 storage units, 90 display devices,
100 reflow furnace, 102 inlet side, 104 outlet side,
CL cooling part, PH preheating part, RF reflow part,
M motor

Claims (4)

A hot air generating section in which a main heater and a fan are disposed;
A transport unit in which a substrate on which electronic components are mounted is transported by a transport means;
A partition plate that partitions between the hot air generation unit and the transport unit;
A plurality of hot air ejection portions formed on the partition plate;
An additional heater provided in at least one of the hot air ejection portions;
A substrate passage detection unit that is disposed in the transport unit and detects the passage of the substrate being transported by the transport unit;
A storage unit in which a transport speed of the transport unit and a mounting position of the electronic component to be heated at a higher temperature than the other electronic components among the electronic components on the substrate are stored in advance,
Based on the passage timing of the substrate detected by the substrate passage detection unit, the transport speed stored in the storage unit, and the mounting position of the high-temperature heating target electronic component on the substrate, a predetermined An operation control unit that controls the operation so that the additional heater is heated at a timing to heat the electronic component to be heated at a high temperature with the hot air generated at a higher temperature than the hot air generated by the hot air generation unit. A reflow furnace that is characterized.   The said additional heater has a cylinder standingly arranged in the hot air generation part side opening part of the said hot-air ejection part, and the heat source accommodated in the said cylinder. Reflow furnace.   The reflow furnace according to claim 2, wherein the cylindrical body is made of a heat insulating material.   The reflow furnace according to claim 2 or 3, wherein the heat source is formed by a heating wire having a spiral shape.

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