JP4925349B2 - Reflow heating method and reflow heating apparatus - Google Patents

Description

  The present invention relates to a reflow heating method and a reflow heating apparatus in which a plurality of transfer lanes are provided in parallel in a reflow furnace, and a mounting substrate is simultaneously transferred in each transfer lane to perform reflow heating.

In recent years, in order to improve the production efficiency of the reflow soldering process, as described in Patent Document 1 (Japanese Patent Laid-Open No. 10-163623), a plurality of conveyance lanes are provided in parallel in the reflow furnace, and each conveyance is performed. In some lanes, the mounting substrate is transported simultaneously and reflow heated.
JP 10-163623 A

  The reflow furnace provided with a plurality of transfer lanes in parallel is designed so that the temperature profile in the reflow furnace is optimized when the mounting substrate is placed on all the transfer lanes and reflow heating is performed. However, the reflow heating is not always performed by mounting the mounting boards on all the transport lanes, and the reflow heating is performed by mounting the mounting boards only on a part of the transport lanes in a plurality of transport lanes, etc. In some cases, the following problems arise.

  In the reflow furnace, the mounting board placed on the transfer lane serves as a heat absorption source that absorbs heat, so when mounting boards are placed only on some transfer lanes, the mounting boards are placed on all transfer lanes. In comparison, not only the total heat absorption amount by each mounting substrate in the reflow furnace is reduced, but also the distribution of the heat absorption sources in the reflow furnace becomes unbalanced. For this reason, as shown in FIG. 2, the temperature profile in the reflow furnace deviates from the optimum temperature profile, and this temperature profile deviation becomes a factor of degrading the quality of reflow soldering.

  The present invention has been made in consideration of such circumstances. Accordingly, the object of the present invention is to carry a mounting board only on a part of the plurality of transportation lanes provided in parallel in the reflow furnace. Thus, even when reflow heating is performed, it is an object to provide a reflow heating method and a reflow heating apparatus that can reduce the deviation of the temperature profile in the reflow furnace and can prevent deterioration in quality of reflow soldering.

  In order to achieve the above object, the invention according to claim 1 is the method of providing a plurality of transfer lanes in a reflow furnace in parallel and simultaneously transporting the mounting substrate in each transfer lane and performing reflow heating. Among the lanes, when the mounting board is mounted on only a part of the transport lanes and transported and reflow-heated, the transport lane on which the mounting board is not placed and the mounting board mounted on the part of the transport lanes and heat absorption characteristics A dummy heated body having similar heat capacity, thermal conductivity, etc.) is placed and transported.

  In this method, by placing a dummy heated body with similar heat absorption characteristics (heat capacity, thermal conductivity, etc.) to the mounting board on the transfer lane where no mounting board is placed, the heat absorption characteristics are similar on all transfer lanes. An endothermic heat source (mounting substrate or dummy heated body) can be placed. As a result, even when the mounting board is mounted on only a part of the transfer lanes and reflow heating is performed, the temperature profile in the reflow furnace can be made to be almost the same as when the mounting board is mounted on all the transfer lanes. The temperature profile deviation in the reflow furnace can be reduced, and the quality of reflow soldering can be prevented from deteriorating.

  Further, according to the present invention, as in claims 2 and 3, a plurality of transfer lanes are provided in parallel in the reflow furnace, and the mounting substrate is simultaneously transferred in each transfer lane and reflow heated. A heat-absorbing means that can control the amount of heat absorbed respectively, and when carrying the reflow heating by mounting the mounting board only on a part of the plurality of transport lanes and carrying the reflow heating, the transport lane that does not carry the mounting board The heat absorption means may be operated to absorb heat, and the amount of heat absorbed may be controlled in accordance with the heat absorption characteristics (heat capacity, thermal conductivity, etc.) of the mounting board mounted on the part of the transfer lanes.

  In this way, if the heat absorption means of the transfer lane on which the mounting board is not mounted is operated to absorb heat, and the amount of heat absorption is controlled according to the heat absorption characteristics (heat capacity, thermal conductivity, etc.) of the mounting board, Even in the transfer lane on which the substrate is not placed, the same heat absorption amount as that of the transfer lane on which the mounting substrate is placed can be secured by the heat absorption means. As a result, even if the mounting board is mounted on only some transfer lanes and reflow heating is performed, the temperature profile in the reflow furnace should be almost the same as that when the mounting board is mounted on all transfer lanes by the heat absorption means. Therefore, the deviation of the temperature profile in the reflow furnace can be reduced, and the deterioration of the quality of reflow soldering can be prevented. In addition, there is no need to prepare a dummy heated body or to perform an operation of placing the dummy heated body on the transfer lane, so that there is an advantage that productivity is not lowered.

  Hereinafter, two Examples 1 and 2, which embody the best mode for carrying out the present invention, will be described.

A first embodiment of the present invention will be described with reference to FIGS.
First, the configuration of the reflow heating device will be described with reference to FIG.
In the reflow furnace 11, two transfer lanes 13 for transferring the mounting substrate 12 are provided in parallel (three or more transfer lanes 13 may be provided in parallel). In the reflow furnace 11, heating means 16 such as a far-infrared heater for heating the mounting substrate 12 is provided in an upper portion of each transfer lane 13.

  Of the two transfer lanes 13 in the reflow furnace 11, when the mounting substrate 12 is mounted and transferred only on one transfer lane 13 (L) and reflow heating is performed, the transfer lane 13 (R ) And a dummy heated body 14 having similar heat absorption characteristics (heat capacity, thermal conductivity, etc.) to the mounting substrate 12 mounted on the one transfer lane 13 (L). The dummy heated body 14 may be formed of a material equivalent to that of the mounting substrate 12, may be formed of a material different from that of the mounting substrate 12, and the dummy heated body may be used. The shape of the body 14 may be substantially the same shape as the mounting substrate 12 or may be a different shape. In short, what is necessary is just to form so that the heat amount which the dummy to-be-heated body 14 absorbs in the reflow furnace 11 becomes substantially the same as the heat amount which the mounting substrate 12 absorbs.

  Further, when the mounting substrate 12 is placed only on one transport lane 13 (L) and the dummy heated bodies 14 are placed on the other transport lane 13 (R), the same number of dummy heated bodies as the number of the mounting substrates 12 is provided. 14 may be placed on the other transport lane 13 (R), or the number of mounting boards 12 and the number of dummy heated bodies 14 may be different.

  When the same number of dummy heated bodies 14 as the number of mounting boards 12 are placed on the other transport lane 13 (R), the amount of heat absorbed by each dummy heated body 14 in the reflow furnace 11 is absorbed by each mounting board 12. What is necessary is just to make it the same as the conveyance space | interval of each mounting substrate 12, while forming so that it may become substantially the same as calorie | heat amount, and the conveyance space | interval of each dummy to-be-heated body 14.

  When the number of mounting substrates 12 and the number of dummy heated bodies 14 are different, the total heat absorption amount of all dummy heated bodies 14 in the reflow furnace 11 is the total absorption amount of all mounted substrates 12 in the reflow furnace 11. The number of dummy heated bodies 14 is set so as to be substantially the same as the amount of heat (or the difference between the total endothermic amounts of the two is reduced), and the number of dummy heated bodies 14 in the reflow furnace 11 is What is necessary is just to set so that the conveyance space | interval of the dummy to-be-heated body 14 may become long, so that there are few.

  In the base 17 on which the reflow furnace 11 is installed, a return conveyor 15 for returning the dummy heated body 14 transported in each transport lane 13 from the outlet side to the inlet side of the reflow furnace 11 is provided. The base 17 and the reflow furnace 11 are partitioned by a heat insulating wall so that the return conveyor 15 in the base 17 is not heated by the heating means 16 in the reflow furnace 11, and the dummy heated body 14 is separated by the return conveyor 15. When returning, the dummy heated body 14 is radiated to reduce the temperature. A forced cooling means such as a cooling fan for forcibly cooling the dummy heated body 14 may be provided in the base 17.

  In this reflow furnace 11, when the mounting substrate 12 is placed on all the transfer lanes 13 and reflow heated, the amount of heat generated and the arrangement of the heating means 16 are optimized so that the temperature profile in the reflow furnace 11 (see FIG. 2) is optimal. The location is set. Therefore, when the mounting substrate 12 is placed on all the transfer lanes 13 and reflow-heated, the mounting substrate 12 may be reflow-heated without using the dummy heated body 14.

  In the reflow furnace 11, the mounting substrate 12 placed on the transport lane 13 serves as an endothermic source that absorbs heat. Therefore, when the mounting substrate 12 is placed only on one transport lane 13 (L), both transport lanes 13 Compared with the case where the mounting substrate 12 is placed on (L, R), not only the total heat absorption amount by each mounting substrate 12 in the reflow furnace 11 is reduced, but also the distribution of the heat absorption source in the reflow furnace 11 is unbalanced. It also becomes a balance. For this reason, when the dummy heated body 14 is not used, as shown in FIG. 2, the temperature profile in the reflow furnace 11 deviates from the optimum temperature profile, and this temperature profile deviation improves the quality of reflow soldering. It becomes a factor to reduce.

  Therefore, in the first embodiment, when the mounting substrate 12 is mounted on only one transfer lane 13 (L) and reflow heating is performed, the dummy heated body 14 is mounted on the transfer lane 13 (R) where the mounting substrate 12 is not mounted. Transport. At this time, the total heat absorption amount of all the dummy heated bodies 14 in the reflow furnace 11 is substantially the same as the total heat absorption amount of all the mounting boards 12 in the reflow furnace 11 (or a difference between the total heat absorption amounts of both). The number of used dummy heated bodies 14 is calculated so that the dummy heated body 14 is conveyed at a conveyance interval corresponding to the number of used.

  In this way, even when the mounting substrate 12 is mounted only on one transfer lane 13 (L) and reflow heating is performed, the temperature profile in the reflow furnace 11 is transferred to both transfer lanes 13 (L, R). Therefore, the temperature profile in the reflow furnace 11 can be reduced, and the quality of reflow soldering can be prevented from deteriorating.

Next, Embodiment 2 of the present invention will be described with reference to FIG. However, substantially the same parts as those in the first embodiment are given the same reference numerals to simplify the description, and mainly different parts will be described.
Also in the second embodiment, two (or three or more) transport lanes 13 are provided in parallel in the reflow furnace 11. In the second embodiment, since the dummy heated body 14 is not used, the return conveyor 15 is not provided in the base 17.

  In the second embodiment, the heat absorption means 18 capable of electrically controlling the amount of heat absorption is installed in each conveyance lane 13. The heat absorbing means 18 is installed, for example, using a Peltier element, with the heat absorbing surface side facing upward, exposed to the heating means 16 side, and the heat generating surface side facing downward. The heat absorption means 18 of each conveyance lane 13 is disposed at a position that does not hinder the conveyance / heating of the mounting substrate 12 so that the conveyance section from the inlet side to the outlet side of each conveyance lane 13 can absorb heat almost uniformly. A heat transporting means (not shown) such as a heat pipe is provided on the heat generating surface side (lower surface side) of each heat absorbing means 18, and the heat radiation from each heat absorbing means 18 is transported to the upper part in the reflow furnace 11 for reflow heating. It may be reused as part of the heat source. Alternatively, a heat radiating means (not shown) such as a heat sink may be provided on the heat generating surface side (lower surface side) of each heat absorbing means 18 so that the heat is radiated from the heat radiating means to the outside of the reflow furnace 11.

  By controlling the applied voltage or current of the heat absorption means 18 for each transport lane 13 with a controller (control means), the heat absorption amount of the heat absorption means 18 can be controlled independently for each transport lane 13.

  When mounting the mounting substrate 12 on all the conveyance lanes 13 and performing reflow heating, the energization to the heat absorption means 18 of all the conveyance lanes 13 is stopped (OFF), and the heat absorption means 18 of all the conveyance lanes 13 absorb the heat. Do not work.

  On the other hand, when the mounting substrate 12 is mounted only on a part of the transfer lanes 13 (L) and reflow heating is performed, only the transfer lane 13 (R) on which the mounting substrate 12 is not mounted is energized to the heat absorption means 18 to absorb heat. While operating, the heat absorption amount (applied voltage or current) of the heat absorption means 18 is controlled by the controller (control means) according to the heat absorption characteristics of the mounting board 12. Specifically, the total heat absorption amount of the heat absorption means 18 in the transfer lane 13 (R) on which the mounting substrate 12 is not placed is substantially the same as the total heat absorption amount of all the mounting substrates 12 in the reflow furnace 11 (or both). The endothermic amount (applied voltage or current) of the endothermic means 18 is controlled so that the difference between the total endothermic amounts becomes smaller.

  In this way, even when the mounting substrate 12 is mounted only on one transfer lane 13 (L) and reflow heating is performed, the temperature in the reflow furnace 11 is increased by the heat absorption operation of the heat absorption means 18 in the other transfer lane 13 (R). The profile can be a temperature profile almost the same as when the mounting substrate 12 is placed on both the transfer lanes 13 (L, R), the temperature profile shift in the reflow furnace 11 can be reduced, and the reflow soldering can be performed. It is possible to prevent deterioration of the attachment quality.

It is a longitudinal cross-sectional view which shows schematically the structure of the reflow furnace of Example 1 of this invention. It is a figure explaining an example of the temperature profile in a reflow furnace. It is a longitudinal cross-sectional view which shows schematically the structure of the reflow furnace of Example 2 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Reflow furnace, 12 ... Mounting board, 13 ... Conveyance lane, 14 ... Dummy heated body, 15 ... Return conveyor, 16 ... Heating means, 17 ... Base, 18 ... Endothermic means

Claims (3)

In the method of providing a plurality of transport lanes in parallel in the reflow furnace and reflow heating by transporting the mounting substrate simultaneously in each transport lane,
Among the plurality of transfer lanes, when mounting and mounting the mounting substrate only on a part of the transport lanes and performing reflow heating, the mounting substrate mounted on the part of the transport lanes on the transport lane not mounting the mounting substrate and A reflow heating method comprising carrying a dummy object to be heated having similar heat absorption characteristics. In the method of providing a plurality of transport lanes in parallel in the reflow furnace and reflow heating by transporting the mounting substrate simultaneously in each transport lane,
Install heat absorption means capable of controlling the amount of heat absorption in each of the transport lanes,
Among the plurality of transport lanes, when the mounting board is mounted on only a part of the transport lanes and transported and reflow-heated, the heat absorbing means of the transport lane on which the mounting board is not mounted is endothermic, and the heat absorption amount is A reflow heating method, wherein control is performed according to a heat absorption characteristic of a mounting substrate placed on the partial transfer lane. In a reflow heating apparatus for providing a plurality of transfer lanes in parallel in a reflow furnace and simultaneously transferring a mounting substrate in each transfer lane and reflow heating,
Endothermic means installed in each of the transport lanes and capable of controlling the amount of heat absorption;
Control means for controlling the heat absorption amount of the heat absorption means of each of the transport lanes,
The control means, when the mounting board is mounted on only a part of the plurality of transport lanes and transported for reflow heating, the heat absorbing means of the transport lane on which the mounting board is not mounted is operated to absorb heat. The reflow heating apparatus is characterized in that the heat absorption amount is controlled in accordance with the heat absorption characteristics of the mounting board mounted on the part of the transfer lanes.

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