JP4043694B2 - Reflow device - Google Patents

Description

【００６３】
また、上述した下側熱風吹き出し部３８は、回路基板２の下面に向けてスリット状のノズルから熱風を吹き付けているが、ノズル形状を上側熱風吹き出し部３２と同様にパイプノズルにより構成してもよい。また、熱風の代わりに冷風を回路基板２の下側に吹き付ける冷風吹き付け手段を設けることにより、例えば回路基板２が両面実装回路基板の場合に、基板裏面が既に前工程で半田付け等されているときに、回路基板２の上面と下面との間の温度差を形成することで、裏面の半田の再溶融を防止でき、電子部品の脱落や熱劣化等の不具合が未然に防止できる。以て、両面実装回路基板に対しても安定して信頼性良くリフロー処理することができる。
【００６４】
次に、本発明に係るリフロー装置の変形例を説明する。本変形例のリフロー装置２００は、図１０に示すように、上側熱風吹き出し部３２のパイプノズル群４４同士の間に遠赤外線や近赤外線等の輻射熱により加熱する輻射熱ヒータ５０を基板搬送方向Ｘに直交するＹ方向に沿って設けている。そして、本変形例においては、この輻射熱ヒータ５０を第１，第２の予熱室１６，１８にそれぞれ１０本ずつ、第１，第２のリフロー加熱室２０，２２それぞれに５本ずつ配設している。これらの輻射熱ヒータ５０は、熱風の影響を受けにくい位置、即ち、回路基板に吹き付けた風が流れる流路から外れた位置に配置することで、パイプノズルからの熱風と輻射熱ヒータとの熱干渉を防いでいる。輻射熱ヒータの加熱時における表面温度は５００℃程度で、熱風は２００℃程度であり、お互いの熱干渉が無いために加熱効率（輻射、熱風）を安定して制御できる。
【００６５】
このように配設された輻射熱ヒータ５０と熱風循環による加熱とを併用することにより、供給熱量を増大でき、熱容量の大きい大型部品の温度上昇を促進させることができる。また、輻射熱ヒータ５０による供給熱量の分だけ熱風循環による供給熱量を相対的に減少させることもできる。これにより、例えば遠赤外線等の熱線を反射するアルミ頂面を有するアルミ電解コンデンサ等の小型部品に対して、熱風温度を低く設定すること等により加熱効果を相対的に低減し、設定温度を超えることが防止できる。
なお、上記輻射熱ヒータ５０は、パイプノズル列の間に輻射熱ヒータ５０を配置（基板搬送方向に平行に配置）した構成としても同様の効果を得ることができる。
また、熱風と輻射熱ヒータとの熱干渉が生じると、連続生産時にヒータ温度がふらつき、加熱量がばらついて品質が悪化するが、この熱干渉が防止されることにより、安定した半田付けが行える。なお、図１１に示すように輻射熱ヒータ５０の下側に耐熱ガラス板５６を配することにより、回路基板２に吹き付けられた熱風が戻ってきて、輻射熱ヒータに当たることを防止できる。
【００６６】
次に、本発明に係るリフロー装置の第２の変形例を説明する。本変形例のリフロー装置３００は、図１２に示すように、上側熱風吹き出し部３２が移動可能に支持されている。即ち、図１２（ａ）では回路基板２面の垂直方向に対して傾斜した方向から熱風が吹き付けられるように、上側熱風吹き出し部３２を揺動可能に支持して、回路基板の加熱時に揺動駆動させる。これにより、パイプノズル４２から吹き出される熱風の回路基板２による淀みをより低減できる。また、図１２（ｂ）では回路基板２面に対して平行に上側熱風吹き出し部３２をスライド移動可能に支持して、スライド駆動することで、パイプノズル４２の配列による熱風強度の違いが平均化され、回路基板２をより均一に加熱することができる。また、スライド駆動の代わりに旋回駆動させてることによっても同様な効果が得られ、さらに、上記各駆動動作を組み合わせて行ってもよい。
そしてさらに、図１３に示すように上側熱風吹き出し部３２のパイプノズル４２を回路基板２面に対して適当な角度θだけ傾斜させ固定することで、熱風の流れを円滑にして淀みを生じさせにくくできる。
【００６７】
また、上側熱風吹き出し部３２のパイプノズル４２の配列は、組立工程を容易にできる図１４（ａ）に示す単純な格子状の他にも、例えば図１４（ｂ）に示すように千鳥状に配列することで、パイプノズル４２の間隔を狭めて、スペース効率の高めて加熱密度を向上させ、より均一に熱風を吹き出す構成としてもよい。
なお、パイプノズル４２の配列を変更可能に構成したり、パイプノズルの長さを任意に設定できるように構成してもよい。さらに、パイプノズル４２を個々に脱着可能とし、長さや内径の異なるパイプや、盲栓と交換可能にすることで、熱風の風量や風速、並びに開閉栓を適宜変更できる構成としてもよい。これにより、回路基板への部品装着状態に応じた最適な加熱効率の高いノズル形状を任意に確定することができる。
【００６８】
また、図１５に示すように、パイプノズル４２の熱風吹き出し側の先端部を基板搬送方向に連続した幅を有して選択的に覆う遮蔽板５２を設けた構成としてもよい。これにより、例えば回路基板２上に基板表面からの突起量が多く熱容量の小さい電子部品３ａが存在する場合に、この電子部品３ａに対して熱風を吹き付けるパイプノズル４２ａの吹き出し口を遮蔽板５２により遮蔽又は閉塞して、電子部品３ａに熱風が直接的に吹き付けられないようにでき、部品の過熱が防止される。なお、この遮蔽板５２は、所望の幅（Ｙ方向幅）にすることで遮蔽する面積を調整でき、移動機構５４によって遮蔽板５２の位置を基板搬送方向Ｘに対して直角な方向（Ｙ方向）に移動自在に設けられる。
【００６９】
【実施例】
次に、本発明に係るリフロー装置によって鉛フリー半田を用いた回路基板２をリフロー処理した実施例を以下に説明する。リフロー装置としては、上側熱風吹き出し部３２のパイプノズル群４４と、回路基板２下側の下側熱風吹き出し部３８から熱風を吹き付ける構成のものを使用した。
図１６にリフロー加熱時間に対する２５０×３３０ｍｍサイズの多層の回路基板２上の各種電子部品３の温度変化を示した。グラフ中の▲１▼〜▲６▼は、表２に示すように、▲１▼は２０８ピンのＱＦＰのリード部分、▲２▼はアルミ電解コンデンサ（直径５ｍｍφ）の上部、▲３▼は回路基板の中央部、▲４▼は３２ピンのＰＬＣＣのリード部分、▲５▼はアルミ電解コンデンサ（直径４ｍｍφ）の上部、▲６▼はＬＥＤの上部の温度を示している。
【００７０】
【表２】

【００７１】
加熱条件としては、表３に示すように、第１の予熱室１６においては上側熱風吹き出し部３２及び下側熱風吹き出し部３８を急加熱のため２２０℃に設定し、第２の予熱室１８においては予熱管理温度（１５０〜１６０℃）に保持するため１５０℃に設定している。また、第１のリフロー加熱室２０おいては上側熱風吹き出し部３２を半田溶融管理温度（２１０〜２２０℃）への急加熱のため３００℃に設定し、第２のリフロー加熱室２２においては半田溶融管理温度に保持するため２６０℃に設定し、さらに第１、第２のリフロー加熱室の下側熱風吹き出し部３８を２６０℃に設定している。
【００７２】
【表３】

【００７３】
上記条件でリフロー処理した結果、回路基板上の各電子部品は、図１６及び表２に示す温度変化を呈した。即ち、前半の予熱期間では、熱容量の小さいＬＥＤ上部▲６▼、アルミ電解コンデンサ上部▲２▼，▲５▼に対しては温度立ち上がり速度が速くなるが、回路基板▲３▼が予熱管理温度に達したときには約１７０℃まで加熱される程度に収まっている。また、熱容量の大きいＱＦＰ▲１▼、ＰＬＣＣ▲４▼は、略回路基板▲３▼と同じ速度で昇温している。
後半のリフロー期間では、予熱期間の加熱パターンと同様にＬＥＤ上部▲６▼、アルミ電解コンデンサ上部▲２▼，▲５▼に対しては温度立ち上がり速度が速く、半田溶融管理温度の２１０〜２２０℃を超えるが、部品の耐熱限界温度（２４０℃）以上には達していない。また、各部の最大温度差ΔＴが１０℃程度に収まっている。
このように、本実施例では設定温度までの加熱を均一に温度のばらつきを抑えて行うことができ、良好なリフロー処理が行えた。
【００７４】
次に、比較例として従来のスリット状の吹き出し口を有する上部及び下部熱風吹き出し部を備えたリフロー装置により上記同様のリフロー処理した結果を図１７及び表４に示した。図１７は、リフロー加熱時間に対する回路基板上の各種電子部品の温度変化を示している。グラフ中の▲７▼,▲８▼は表４に示すように、▲７▼が１６ピンのＳＯＰの上部、▲８▼が６４ピンのＱＦＰの上部の温度を示している。他の▲１▼〜▲６▼は先述と同一の部品を示している。
【００７５】
【表４】

【００７６】
図１７及び表４に示すように、各部品の温度変化は、予熱時及びリフロー加熱時共に温度のばらつきが大きくなっている。即ち、前半の予熱期間では、熱容量の小さいＬＥＤ上部▲６▼、アルミ電解コンデンサ上部▲２▼，▲５▼に対しては予熱管理温度の上限温度（１６０℃）を３０℃程度も上回る温度に加熱される一方、熱容量の大きいＱＦＰ▲１▼,▲８▼は立ち上がり速度が遅く、回路基板▲３▼の温度より低くなっており、予熱管理温度の下限温度（１５０℃）に達するまで長い時間を要している。
後半のリフロー期間では、予熱期間の加熱パターンと同様にＬＥＤ上部▲６▼、アルミ電解コンデンサ上部▲２▼，▲５▼に対しては温度立ち上がり速度が速く、半田溶融管理温度の２１０〜２２０℃を大きく超えて、ピーク温度が部品の耐熱限界温度（２４０℃）以上に達している。一方、ＱＦＰ▲１▼,▲８▼及びＰＬＣＣ▲４▼の温度が半田溶融管理温度の下限温度（２１０℃）に達するまで長い時間を要している。そして、リフロー期間内の各部の最大温度差ΔＴは４０℃程度となり、温度のばらつきが大きく、部品不良や半田の未溶融といった問題を生じ易くなる。さらに、回路基板２への加熱が不均一で安定していないため、基板間の温度差も大きい。
【００７７】
【発明の効果】
本発明によれば、熱風を複数のパイプノズルから回路基板に向けて吹き付ける際に、パイプノズルによる複数の熱風吹き付け点を回路基板に対して平面状に分散させることにより、熱風の吹き付けを回路基板面に対して均一化できる。
また、吹き付けられた熱風が回路基板から跳ね返った後に、配列されたパイプノズル同士間の空間によって形成される流路を通って熱風が炉体内を循環することで、熱風が淀むことを大幅に低減でき熱伝達効率を低下させることなく効率良く熱風を循環させることができる。
さらに、各パイプノズル群間のピッチより各パイプノズル列間のピッチを広くしたこと、により、回路基板から跳ね返った熱風の経路を確実に確保でき、熱風の循環効果が向上して、熱風の淀みがより低減される。
このように熱風の淀みが低減されて回路基板の温度ばらつきを低減できるため、鉛フリー半田に対しても良好なリフロー処理が可能となる。
【図面の簡単な説明】
【図１】本発明に係るリフロー装置全体の縦断面図である。
【図２】図１に示すリフロー装置の上蓋部を開いた状態を示すリフロー装置の全体斜視図である。
【図３】リフロー装置のリフロー加熱室の拡大図である。
【図４】図３のＡ−Ａ断面斜視図である。
【図５】熱風吹き出し部の一部拡大斜視図である。
【図６】隔離板とパイプノズルとを接続する手順を示す図である。
【図７】第１，第２の予熱室及び第１，第２のリフロー加熱室を通過する際に温度制御する温度プロファイルを示す図である。
【図８】上側熱風吹き出し部からの熱風を回路基板に吹き付けて回路基板を加熱する様子を説明する図である。
【図９】鉛フリー半田を用いた回路基板をリフロー処理する際のリフロー加熱時間に対する基板温度の変化を示す図である。
【図１０】本発明に係るリフロー装置の変形例としての上側熱風吹き出し部のパイプノズル群同士の間に赤外線ヒータを設けた構成を示す図である。
【図１１】輻射熱ヒータの下側に耐熱ガラス板を設けた構成を示す図である。
【図１２】本発明に係るリフロー装置の第２変形例における上側熱風吹き出し部が移動可能に支持された構成を示す図である。
【図１３】上側熱風吹き出し部のパイプノズルを回路基板面に対して傾斜させて固定した構成を示す図である。
【図１４】上側熱風吹き出し部のパイプノズルの配列を示す図である。
【図１５】パイプノズルの先端に遮蔽板を設けた構成を示す図である。
【図１６】リフロー加熱時間に対する回路基板上の各種電子部品の温度変化を示す図である。
【図１７】図１５に対応する従来のスリット状の吹き出し口を有する上部及び下部熱風吹き出し部を備えたリフロー装置によりリフロー処理した結果を示す図である。
【図１８】特開平６−６１６４０号公報に記載のリフロー装置を示す図である。
【図１９】従来の熱風を吹き付ける手法とそのときの熱風の淀みを示す図で、（ａ）はファンにより熱風を吹き付ける場合で（ｂ）はスリット状の熱風吹き付けノズルにより熱風を吹き付ける場合を示している。
【図２０】特許第２７８２７９１号に記載のリフロー装置を示す図である。
【図２１】従来の熱風から回路基板への熱伝達効率、熱風温度に対する回路基板温度の応答性を説明する図である。
【符号の説明】
２ 回路基板
３ 電子部品
１０ 基板搬入口
１２ 基板搬出口
１４ 基板搬送手段
１６ 第１の予熱室
１８ 第２の予熱室
２０ 第１のリフロー加熱室
２２ 第２のリフロー加熱室
２６ シロッコファン
２８ ヒータ
３２ 上側熱風吹き付け部
３４ 熱風吸い込み部
３７ 熱風吹き出し口
３８ 下側熱風吹き出し部
４０ 隔離板
４２ パイプノズル
４４ パイプノズル群
５０ 赤外線ヒータ
５２ 遮蔽板
５４ 移動機構
１００，２００，３００ リフロー装置[0001]
BACKGROUND OF THE INVENTION
  The present invention is a process of mounting an electronic component on a circuit board, and soldering the electronic component.Reflow equipment to performAbout.
[0002]
[Prior art]
In a reflow apparatus for soldering electronic components to a circuit board, heating by hot air heated to a predetermined temperature, heating by radiant heat such as infrared rays, or a heating method combining these is used as the heating means.
Here, as an example of a method for heating a circuit board by circulating heated hot air, a reflow apparatus described in Japanese Patent Laid-Open No. 6-61640 is shown in FIG. The reflow apparatus shown in FIG. 18 includes a board transfer means 71 for transferring the circuit board 70 from the inlet to the outlet, an air circulation path 73 for circulating air by the sirocco fan 72, and an air heating means for heating the circulating air to a predetermined temperature. 74, the sirocco fan 72 circulates a predetermined amount of air, and the air heating means 74 heats the circulating air to a predetermined temperature. The circuit board 70 is reflow soldered by blowing the heated circulating air (hot air) onto the upper surface of the circuit board 70.
[0003]
[Problems to be solved by the invention]
However, when hot air is blown onto the circuit board to heat the circuit board with the above-described configuration, temperature variation occurs in the circuit board. One of the causes is that when hot air is blown onto the circuit board 70, a wind stagnation point is generated at a position where the hot air is blown onto the circuit board 70, and the temperature rise is partially prevented. . For example, when hot air is blown by the fan shown in FIG. 19A, stagnation of hot air occurs immediately below the fan, and the temperature rise of the circuit board does not become uniform with respect to the substrate surface, resulting in partial temperature variations. Occurs. In addition, as shown in FIG. 19B, when hot air is blown by a slit-like hot air blowing nozzle, hot air stagnation occurs directly under the nozzle, and this also causes local temperature variations. Arise.
[0004]
For this reason, for example, in the reflow apparatus described in Japanese Patent No. 2778791 shown in FIG. 20, a hot air blowing nozzle 77 that blows heated air toward the circuit board 70 is provided. By forming the exhaust air suction hole 78 that discharges the hot air or cooling air bounced off from the circuit board 70 after being blown out in a direction opposite to the blowing direction from the hot air blowing nozzle 77, it is cooled after heat transfer. After the hot air bounces off the circuit board, it is immediately discharged from the exhaust hole, so that the circuit board can always be supplied with hot air at a constant temperature.
[0005]
However, since the structure for spraying hot air is complicated in the reflow device configured as described above, there is a problem that it is difficult to reduce the manufacturing cost of the device, and it has been desired to spray hot air with a simpler structure.
[0006]
As another cause of the temperature variation, the amount of heating for raising the circuit board is controlled by the temperature of the hot air, so that the heat transfer efficiency from the hot air to the circuit board and the circuit board temperature relative to the hot air temperature are It is mentioned that the responsiveness has a big influence. That is, as the target temperature increases, the hot air temperature is set to a temperature higher than the target temperature in order to quickly raise the temperature of the circuit board. Therefore, as shown in FIG. While the electronic component is heated to a temperature higher than the target temperature, the electronic component having a large heat capacity may not reach the target temperature, and the reflow process may end without the solder being melted. As described above, the difference ΔT between the maximum temperature and the minimum temperature on the circuit board in the reflow process.₁Tends to increase, and this temperature difference ΔT₁It is necessary to reduce the amount of heat and to heat uniformly. Also, the temperature difference ΔT between circuit boards₂Reduction is also necessary.
[0007]
In particular, when a lead-free solder containing no lead component is used, for example, the melting point of Sn-Ag, Sn-Cu, and Sn-Zn lead-free solder is 200 ° C. or higher, and the melting point of Sn—Pb solder ( 183 ° C.), the temperature difference ΔT₁The problem becomes prominent. That is, when heating at a target heating temperature of 240 ° C. using lead-free solder, when the hot air temperature is set to 300 ° C. to 350 ° C., for example, the component having a small heat capacity is heated to a temperature higher than the set temperature. When the heat resistant limit temperature of the heat resistant electronic component (for example, 240 ° C. to 250 ° C.) is exceeded, the quality of the component is deteriorated.
[0008]
  The present invention has been made in view of such conventional problems. When hot air for heating is blown to a circuit board, the temperature variation of the circuit board is reduced by reducing the stagnation of the hot air, and lead-free. Good reflow treatment for solderPossible reflow deviceThe purpose is to provide.
[0013]
[Means for Solving the Problems]
  In order to achieve the above object, claim 1 according to the present invention is described.The reflow apparatus is supplied from the furnace body, a substrate transport means for transporting a circuit board on which electronic components are mounted in the furnace body, hot air heating means for heating the air in the furnace body, and the hot air heating means. Hot air blowing means comprising a plurality of pipe nozzles arranged at predetermined intervals for blowing hot air on the surface of the circuit board, and blowing the hot air from the pipe nozzles of the hot air blowing means to the circuit board, A plurality of hot air blowing points are dispersed on the substrate plane, and after the blown hot air bounces off the circuit board, the hot air is circulated through the flow path formed by the space between the arranged pipe nozzles. MakeIn the reflow apparatus, the hot air blowing means forms a plurality of pipe nozzle groups each composed of a plurality of pipe nozzle rows in which the pipe nozzles are arranged in a direction substantially perpendicular to the substrate transport direction, and each pipe nozzle in the substrate transport direction. The pitch between groups was made wider than the pitch between each pipe nozzle rowIt is characterized by that.
[0014]
  In this reflow apparatus, by blowing hot air from the pipe nozzle of the hot air blowing means to the circuit board, the hot air blowing can be made uniform on the circuit board surface by dispersing a plurality of hot air blowing points on the circuit board plane. In addition, after the blown hot air bounces off the circuit board, it passes through a flow path formed by the space between the arranged pipe nozzles, so that hot air can be greatly reduced and heat transfer efficiency is reduced. It is possible to circulate hot air efficiently without any problems.
  Furthermore, by making the pitch between each pipe nozzle row wider than the pitch between each pipe nozzle group, the path of hot air bounced off the circuit board can be surely secured, the circulation effect of hot air is improved, and the hot air stagnation Is further reduced.
  Thereby, the supply air volume of a hot air can also be increased and the dispersion | variation in the temperature in a circuit board can be reduced.
  Therefore, even a circuit board using lead-free solder whose melting point is close to the heat resistant limit temperature of the component can be satisfactorily reflowed.
[0016]
In this reflow apparatus, hot air is blown from above the circuit board by hot air blowing means, whereby the cream solder on the upper surface of the circuit board is reflow soldered.
[0018]
In this reflow apparatus, the electronic component having a large heat capacity can be quickly and stably heated to a predetermined temperature by having the lower hot air blowing part.
[0020]
In this reflow device, by blowing cold air from below the circuit board, a temperature difference is formed between the upper surface and the lower surface of the circuit board, and the solder that has already been soldered to the lower surface of the double-sided mounted circuit board in the previous process. It is possible to prevent parts from falling off and heat deterioration, and to perform a reflow process on a double-sided mounted circuit board stably and reliably.
[0022]
In this reflow apparatus, by providing a plurality of pipe nozzle rows in which the pipe nozzles are arranged in a direction perpendicular to the substrate transport direction in the substrate transport direction, hot air is blown evenly over the entire surface of the circuit board being transported. For this reason, the dispersion | variation in the temperature in a board | substrate is reduced.
[0024]
In this reflow device, by arranging the pipe nozzle groups in the transport direction, the hot air bounced off the circuit board can pass through the pipe nozzles more smoothly, improving the hot air circulation effect, The itch is further reduced.
[0026]
In this reflow device, by providing a radiant heat heater between adjacent pipe nozzle groups, the radiant heat heater and the hot air circulation can be used together to heat, increasing the amount of heat supplied and increasing the temperature of large parts with large heat capacity. Can be promoted. In addition, since the amount of heat supplied by hot air circulation can be relatively reduced by the amount of heat supplied by the radiant heat heater, the heating effect can be improved by setting the hot air temperature low for components having surfaces that reflect radiant heat. It can be relatively reduced to prevent the set temperature from being exceeded.
[0028]
In this reflow device, by arranging the radiant heat heater at a position away from the flow path through which the wind blown on the substrate flows, it is possible to prevent thermal interference between the hot air and the radiant heat heater, and to stabilize the heating efficiency by hot air and radiation. Can be controlled. As a result, stable soldering can be performed.
[0030]
In this reflow apparatus, the hot air is blown substantially perpendicularly to the circuit board, so that the heat transfer efficiency is improved and the circuit board can be heated more effectively.
[0032]
In this reflow device, the hot air blowing means is driven to swing, whereby the direction of hot air blowing from the pipe nozzle changes, and the stagnation of hot air is reduced, so that the circuit board can be heated more uniformly.
[0034]
In this reflow apparatus, the hot air spraying means is driven to slide, so that the hot air spray position from the pipe nozzle changes, and the hot air spray is averaged to heat the circuit board more uniformly.
[0036]
In this reflow apparatus, the pipe nozzles are arranged in a lattice pattern, so that a simple configuration can be achieved and the assembly process can be facilitated.
[0038]
In this reflow apparatus, the pipe nozzles are arranged in a staggered manner, so that the interval between adjacent pipe nozzles can be narrowed, a configuration with higher space efficiency can be achieved, and the heating density can be improved.
[0040]
In this reflow apparatus, for example, when an electronic component that is easily overheated by hot air exists on the circuit board, the hot air can be prevented from being directly blown to the electronic component that is easily overheated.
[0042]
In this reflow apparatus, by separating the outlet of the pipe nozzle by at least 25 mm from the mounting position of the circuit board, interference between components on the circuit board and the pipe nozzle can be prevented while increasing the heating efficiency by hot air.
[0043]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a reflow method and a reflow apparatus according to the present invention will be described below in detail with reference to the drawings.
Here, FIG. 1 is a longitudinal sectional view of the entire reflow apparatus according to the present invention, FIG. 2 is an overall perspective view of the reflow apparatus showing an open state of the upper cover of the reflow apparatus shown in FIG. 1, and FIG. FIG. 4 is an enlarged perspective view of the heating chamber, and FIG.
[0044]
As shown in FIG. 1, the reflow apparatus 100 of the present embodiment includes a substrate transfer means 14 for transferring a circuit board 2 between a substrate carry-in port 10 and a substrate carry-out port 12, and a substrate carry-out port from the substrate carry-in port 10 side. The first and second preheating chambers 16 and 18 and the first and second reflow heating chambers 20 and 22, the cooling unit 24, and each part of the furnace body that constitute the furnace body arranged side by side on the 12 side. And a control unit (not shown) for controlling the temperature.
[0045]
As shown in FIG. 4, the first and second preheating chambers 16 and 18 and the first and second reflow heating chambers 20 and 22 are respectively a sirocco fan 26 that circulates air in the furnace body and circulated air. Is provided with a heater 28 for heating. The upper hot air blowing section 32 is disposed above the board conveying means 14, passes the hot air heated by the heater 28 downward through the rectifying plate 35, supplies the hot air to the hot air blowing opening 37, and is placed on the upper surface of the circuit board 2. Spray toward. On the other hand, the hot air sucking section 34 is disposed below the board conveying means 14 and sucks heated air blown onto the circuit board 2.
[0046]
In addition, the cooling unit 24 includes a cooling fan 36 that blows outside air taken in from an outside air intake port (not shown) to the circuit board 2.
For the first preheating chamber 16 and the first and second reflow chambers 20 and 22, the circuit board conveyed by the board conveying means 30 below the circuit board 2 and above the hot air suction part 34. A lower hot air blowing portion 38 that is blown onto the lower surface of 2 is disposed. As shown in FIG. 4, the lower hot air blowing section 38 sends hot air to the lower surface of the circuit board 2 by sending air heated by the heater from the slit-shaped blowing port by the second sirocco fan 27. Yes.
[0047]
With the above configuration, the reflow apparatus 100 according to the present embodiment includes, as shown in FIG. 1, the first and second preheating chambers 16 and 18 and the first and second reflow heating chambers 20 constituting the furnace body. , 22, hot air heated to a predetermined temperature by the respective heaters 28 is blown onto the upper surface or upper and lower surfaces of the circuit substrate 2 with respect to the circuit substrate 2 conveyed by the substrate conveying means 14.
[0048]
The present invention is configured by using, as the hot air blowing port 37 of the upper hot air blowing unit 32 of the reflow apparatus 100, a pipe nozzle composed of a plurality of pipes arranged at a predetermined interval substantially perpendicular to the surface of the circuit board 2. In addition, hot air is blown from the plurality of pipe nozzles toward the circuit board.
Here, a specific configuration of the upper hot air blowing section 32 of the reflow apparatus 100 will be described. As shown in a partially enlarged perspective view of FIG. 5, the upper hot air blowing section 32 has a predetermined length in an opening hole 40a formed in the separator plate 40 that separates the rectifying plate 35 side and the circuit board 2 side. The pipe nozzle 42 is fixed vertically toward the circuit board 2 side.
[0049]
The pipe nozzles 42 are arranged in a straight line so that hot air can be blown over the entire maximum substrate width of the substrate transfer means 14 in the Y direction which is orthogonal to the transfer direction X of the circuit board 2. And from this arrangement of pipe nozzles 42 in the Y direction, L in the X direction.₁A group of pipe nozzles 44 is formed by arranging a row of pipe nozzles 42 at positions further apart from each other. This pitch L₁The pipe nozzle group 44 composed of two pipe nozzle rows arranged in the₂The hot air blowing port 37 is formed by repeatedly arranging them at positions apart from each other. Therefore, each pipe nozzle 42 is L as a distance to at least the adjacent pipe nozzle 42.₁And a space between the pipe nozzle groups 44 is L.₂Space is secured. These spaces serve as hot air flow paths that bounce off the circuit board.
[0050]
The pipe nozzle 42 has an inner diameter of 8 mm or more and 25 mm or less, and the length of the pipe nozzle 42 (h₁) Is a length in which a space from the upper surface of the circuit board 2 to a height of 60 mm or more, preferably 200 mm or more is formed.
In addition, the distance (h from the placement position of the circuit board 2 to the lower end of the pipe nozzle₂) Is set to 25 mm or more. Although the heating efficiency is improved if the outlet of the pipe nozzle 42 is located at a position less than 25 mm from the mounting position of the circuit board 2, the parts mounted or inserted on the circuit board 2 are about 20 mm at maximum, If the minimum clearance with the nozzle is 5 mm, h₂Is required to be at least 25 mm. Thereby, interference with components and the pipe nozzle 42 can be prevented, improving heating efficiency.
[0051]
  The pitch between the pipe nozzles 42 is, for example, 20 mm pitch L1 and 40 mm pitch L2.it can. Also,The pipe nozzle 42 may have a hollow prismatic shape or the like in addition to the cylindrical shape. In this case, the cross-sectional area of the inner peripheral surface of the pipe nozzle 42 is set to 50 mm 2 or more and 500 mm 2 or less. Furthermore, in addition to the constant inner diameter, it may be in the form of a tip. In addition, the hot air circulation fan such as the sirocco fan 26 is rotated and adjusted so that the hot air blowing speed from the pipe nozzle 42 is 2 m / s or more and 6 m / s or less on the circuit board 2.
[0052]
Here, a method for assembling the outlet 37 of the upper hot air outlet 32 will be described. FIG. 6 shows a procedure for connecting the separator plate 40 and the pipe nozzle 42.
First, as shown in FIG. 6A, an opening hole 40 a for fixing the pipe nozzle 42 is formed in the separator plate 40. Further, a stepped portion 42a whose outer diameter is fitted into the opening hole 40a is formed on the proximal end side of the pipe nozzle 42, and the stepped portion 42a of the pipe nozzle 42 is fitted into the opening hole 40a.
Next, as shown in FIG. 6B, the stepped portion 42a of the pipe nozzle 42 protruding from the opening hole 40a of the separator plate 40 is crushed from the direction opposite to the direction in which the pipe nozzle 42 is inserted. Secure as shown in c).
[0053]
In the figure, only one pipe nozzle is shown for explanation, but a plurality of pipe nozzles are arranged in a plane as shown in FIG. It can be carried out efficiently by forming punch holes by one to several presses.
Further, the pipe nozzle may be fixed by screws or may be fixed by providing a hook portion. According to these methods, the pipe nozzle can be detached.
[0054]
Next, the operation of the reflow apparatus of this embodiment when a reflow process is performed on a circuit board such as a high-density mounting board using lead-free solder will be described.
First, the circuit board 2 on which the electronic component 3 is placed on the cream solder on the upper surface of the circuit board 2 is supplied to the board carry-in entrance 10, and the circuit board 2 is carried to the board carry-out exit 12 by the board carrying means 30 ( 1 and 2). At this time, when the circuit board 2 passes through the first and second preheating chambers 16 and 18 and the first and second reflow heating chambers 20 and 22, the temperature control is performed so that the temperature profile shown in FIG. Is done. That is, the preheating period t in the first and second preheating chambers 16 and 18.₁, The circuit board 2 is heated to about 150 ° C., and the reflow heating period t in the first and second reflow heating chambers 20 and 22 is set.₂, The lead-free solder (melting point: about 220 ° C.) is heated to about 240 ° C., which is the reflow heating temperature. Then, it controls so that it may be cooled in the cooling unit 24.
[0055]
Here, stage I in FIG. 7 is a preheating temperature raising step by the first preheating chamber 16 of the reflow apparatus 100, stage II is a preheating temperature holding step by the second preheating chamber 18, and stage III is the first reflow heating chamber. Reflow heating process 20, stage IV corresponds to the reflow heating temperature holding process using the second reflow heating chamber 22, and stage V corresponds to the cooling process using the cooling unit 24.
[0056]
Specifically, in each stage, the set temperature of the heater 28 in each of the first and second preheating chambers 16 and 18 and the first and second reflow heating chambers 20 and 22 and the sirocco fan 26 (second sirocco). The hot air flow rate by the fan 27) is set to a temperature and a flow rate corresponding to the heat capacity of the circuit board 2 to be reflow processed and the board transfer speed.
[0057]
Here, how the hot air from the upper hot air blowing section 32 is blown onto the circuit board 2 to heat the circuit board will be described with reference to FIG.
As shown in FIG. 8, the upper hot air blowing section 32 of the present embodiment has a height h of a pipe nozzle 42 that is suspended downward from the separator plate 40.₁Is the height h from the lower end of the pipe nozzle 42 to the circuit board 2₂The hot air blown from the pipe nozzle 42 bounces off the circuit board 2 and then easily passes through the flow path formed by the space between the pipe nozzles around each pipe nozzle 42. It has a configuration that can. That is, since the hot air to the circuit board 2 is blown substantially perpendicularly to the circuit board 2, and the hot air after the heat transfer is quickly discharged from the periphery of the pipe nozzle 42, a high heat transfer rate can be obtained. it can. A stable high-temperature atmosphere is always formed between the tip of the pipe nozzle 42 and the circuit board 2.
[0058]
For this reason, according to the above configuration, the opening area around the pipe nozzle 42 is expanded, a sufficient circulation path for the blown hot air is ensured, and the hot air blowing ports are dispersed in a plane with respect to the circuit board surface. As a result, the area of the hot air stagnation point can be greatly reduced. As a result, stagnation is less likely to occur even if the supply air volume is increased, and it is possible to supply a desired amount of heat to the circuit board 2 by lowering the hot air temperature and increasing the supply air volume. Overheating can be suppressed and the heating temperature can be made stable and uniform. As a result, the temperature difference between the large heat capacity component and the small component can be reduced, and the temperature of the circuit board 2 can be set with high accuracy up to the target reflow heating temperature. It is possible to reliably prevent problems due to insufficient heating even for heating above the temperature and lead-free solder having a high melting point. Thus, even when lead-free solder is used, good reflow processing can be performed, and a highly reliable mounting circuit board can be obtained.
[0059]
FIG. 9 shows changes in the substrate temperature with respect to the reflow heating time when the circuit substrate using lead-free solder is subjected to reflow processing. As shown in FIG. 9, in the profile of the conventional reflow method, the body of a small component (for example, an aluminum electrolytic capacitor) having a small heat capacity exceeds the preheating management temperature of 150 to 160 ° C. at the end of the preheating temperature rising step I. While being heated, the lead of a large component (for example, QFP) having a large heat capacity has not reached the preheat control temperature. This temperature difference ΔT₁Is maintained without falling within the preheating management temperature range even when the preheating temperature holding step II ends. From this state, when heated by the reflow heating process III, the temperature difference ΔT between the small component and the large component exceeds the reflow heating temperature range of 230 to 240 ° C.₁Expands further.
[0060]
On the other hand, when the reflow process is performed by the reflow apparatus 100 of the present embodiment, the temperature is controlled so as to be within the target profile having a slight temperature difference in the reference profile. As a result, the temperature difference ΔT between the large component and the small component can be obtained not only during preheating but also during reflow heating to a higher temperature.₁And temperature difference ΔT between substrate and substrate₂Is controlled to be within 10 ° C., and variations in substrate temperature are greatly reduced.
[0061]
Table 1 shows the properties and heating conditions of Sn—Ag—Bi—In and Sn—Ag—Cu solder as examples of lead-free solder. Since the melting point of Sn—Ag—Cu solder is about 10 ° C. higher than that of Sn—Ag—Bi—In solder, the solder melting management temperature is set to 230 ° C. By performing the reflow process under the heating conditions shown in Table 1, the temperature difference ΔT in the substrate₁And substrate temperature difference ΔT₂Can be kept at 20 ° C. for Sn—Ag—Bi—In solder and 10 ° C. for Sn—Ag—Cu solder.
[0062]
[Table 1]

[0063]
The lower hot air blowing portion 38 described above blows hot air from the slit-shaped nozzle toward the lower surface of the circuit board 2, but the nozzle shape may be configured by a pipe nozzle in the same manner as the upper hot air blowing portion 32. Good. Further, by providing cold air blowing means for blowing cold air to the lower side of the circuit board 2 instead of hot air, for example, when the circuit board 2 is a double-sided mounted circuit board, the back surface of the board is already soldered in the previous process. Sometimes, by forming a temperature difference between the upper surface and the lower surface of the circuit board 2, remelting of the solder on the back surface can be prevented, and problems such as dropout of electronic components and thermal deterioration can be prevented. Therefore, the reflow process can be stably and reliably performed on the double-sided mounted circuit board.
[0064]
Next, a modification of the reflow apparatus according to the present invention will be described. As shown in FIG. 10, the reflow apparatus 200 according to the present modification includes a radiant heat heater 50 that heats between the pipe nozzle groups 44 of the upper hot air blowing section 32 by radiant heat such as far infrared rays and near infrared rays in the substrate transport direction X. It is provided along the orthogonal Y direction. In this modification, ten radiant heaters 50 are arranged in each of the first and second preheating chambers 16 and 18 and five in each of the first and second reflow heating chambers 20 and 22. ing. These radiant heat heaters 50 are arranged at positions that are not easily affected by hot air, that is, positions that are out of the flow path through which the wind blown to the circuit board flows, thereby preventing thermal interference between the hot air from the pipe nozzle and the radiant heat heater. It is preventing. The surface temperature at the time of heating of the radiant heater is about 500 ° C., the hot air is about 200 ° C., and since there is no mutual heat interference, the heating efficiency (radiation, hot air) can be controlled stably.
[0065]
The combined use of the radiant heat heater 50 arranged in this way and heating by hot air circulation can increase the amount of heat supplied and promote the temperature rise of large components having a large heat capacity. Further, the amount of heat supplied by hot air circulation can be relatively reduced by the amount of heat supplied by the radiant heat heater 50. As a result, for example, for a small part such as an aluminum electrolytic capacitor having an aluminum top surface that reflects heat rays such as far-infrared rays, the heating effect is relatively reduced by setting the hot air temperature low, and the set temperature is exceeded Can be prevented.
The radiant heat heater 50 can obtain the same effect even when the radiant heat heater 50 is disposed between the pipe nozzle rows (arranged parallel to the substrate transport direction).
Further, when thermal interference between the hot air and the radiant heat heater occurs, the heater temperature fluctuates during continuous production, and the amount of heating varies, thereby deteriorating the quality. However, by preventing this thermal interference, stable soldering can be performed. As shown in FIG. 11, by disposing the heat-resistant glass plate 56 below the radiant heat heater 50, it is possible to prevent the hot air blown to the circuit board 2 from returning and hitting the radiant heat heater.
[0066]
Next, a second modification of the reflow apparatus according to the present invention will be described. As shown in FIG. 12, the reflow apparatus 300 of this modification has the upper hot air blowing part 32 supported so as to be movable. That is, in FIG. 12A, the upper hot air blowing portion 32 is supported so as to be swingable so that hot air is blown from a direction inclined with respect to the vertical direction of the surface of the circuit board 2, and swings when the circuit board is heated. Drive. Thereby, the stagnation by the circuit board 2 of the hot air which blows off from the pipe nozzle 42 can be reduced more. In FIG. 12B, the difference in hot air intensity due to the arrangement of the pipe nozzles 42 is averaged by supporting the upper hot air blowing portion 32 so as to be slidable parallel to the surface of the circuit board 2 and slidingly driving it. Thus, the circuit board 2 can be heated more uniformly. Further, the same effect can be obtained by rotating the driving instead of the sliding driving, and the above driving operations may be combined.
Further, as shown in FIG. 13, the pipe nozzle 42 of the upper hot air blowing section 32 is inclined and fixed with respect to the surface of the circuit board 2 by an appropriate angle θ, so that the flow of hot air is made smooth and it is difficult to cause stagnation. it can.
[0067]
Further, the arrangement of the pipe nozzles 42 of the upper hot air blowing section 32 is, for example, a staggered pattern as shown in FIG. 14B, in addition to the simple lattice shape shown in FIG. The arrangement may be such that the interval between the pipe nozzles 42 is narrowed, the space efficiency is increased, the heating density is improved, and hot air is blown out more uniformly.
Note that the arrangement of the pipe nozzles 42 can be changed, or the length of the pipe nozzles can be arbitrarily set. Furthermore, the pipe nozzles 42 can be individually attached and detached, and can be replaced with pipes having different lengths and inner diameters, or can be replaced with blind plugs, so that the hot air flow rate, wind speed, and open / close plug can be changed as appropriate. Thereby, the optimal nozzle shape with high heating efficiency according to the component mounting state to the circuit board can be arbitrarily determined.
[0068]
Further, as shown in FIG. 15, a configuration may be provided in which a shielding plate 52 is provided that selectively covers the tip of the pipe nozzle 42 on the hot air blowing side with a continuous width in the substrate transport direction. Thereby, for example, when there is an electronic component 3a with a large projection amount from the substrate surface and a small heat capacity on the circuit board 2, the air outlet of the pipe nozzle 42a that blows hot air against the electronic component 3a is formed by the shielding plate 52. By shielding or closing, it is possible to prevent the hot air from being directly blown onto the electronic component 3a, thereby preventing overheating of the component. The shielding plate 52 can be adjusted to have a desired width (width in the Y direction), and the area to be shielded can be adjusted. ) Is movably provided.
[0069]
【Example】
Next, an embodiment in which the circuit board 2 using lead-free solder is reflowed by the reflow apparatus according to the present invention will be described below. As the reflow apparatus, a configuration in which hot air is blown from the pipe nozzle group 44 of the upper hot air blowing portion 32 and the lower hot air blowing portion 38 below the circuit board 2 was used.
FIG. 16 shows temperature changes of various electronic components 3 on the multilayer circuit board 2 having a size of 250 × 330 mm with respect to the reflow heating time. (1) to (6) in the graph are as shown in Table 2, (1) is the lead part of the 208-pin QFP, (2) is the upper part of the aluminum electrolytic capacitor (diameter 5 mmφ), and (3) is the circuit The center part of the substrate, (4) indicates the lead portion of the 32-pin PLCC, (5) indicates the upper part of the aluminum electrolytic capacitor (diameter 4 mmφ), and (6) indicates the temperature of the upper part of the LED.
[0070]
[Table 2]

[0071]
As the heating conditions, as shown in Table 3, in the first preheating chamber 16, the upper hot air blowing section 32 and the lower hot air blowing section 38 are set to 220 ° C. for rapid heating, and in the second preheating chamber 18. Is set to 150 ° C. in order to maintain the preheating control temperature (150 to 160 ° C.). In the first reflow heating chamber 20, the upper hot air blowing portion 32 is set to 300 ° C. for rapid heating to the solder melting management temperature (210 to 220 ° C.). In order to maintain the melt management temperature, the temperature is set to 260 ° C., and the lower hot air blowing portion 38 of the first and second reflow heating chambers is set to 260 ° C.
[0072]
[Table 3]

[0073]
As a result of the reflow process under the above conditions, each electronic component on the circuit board exhibited a temperature change shown in FIG. That is, in the first half of the preheating period, the temperature rise speed is faster for the LED upper portion (6) and the aluminum electrolytic capacitor upper portions (2) and (5) with a small heat capacity, but the circuit board (3) is at the preheating management temperature. When it reaches, it is within the range of being heated to about 170 ° C. Further, QFP (1) and PLCC (4) having large heat capacities are heated at substantially the same speed as the circuit board (3).
In the second half of the reflow period, as with the heating pattern in the preheating period, the temperature rise speed is fast for the upper LED portion 6 and the aluminum electrolytic capacitor upper portions 2 and 5, and the solder melting management temperature is 210 to 220 ° C. However, the temperature does not reach the heat resistant limit temperature (240 ° C.) of the part. Further, the maximum temperature difference ΔT of each part is within about 10 ° C.
As described above, in this example, heating up to the set temperature can be performed uniformly while suppressing variations in temperature, and a good reflow process can be performed.
[0074]
Next, FIG. 17 and Table 4 show the results of a reflow process similar to that described above using a conventional reflow apparatus including upper and lower hot air blowing portions having slit-like blowing ports as a comparative example. FIG. 17 shows temperature changes of various electronic components on the circuit board with respect to the reflow heating time. As shown in Table 4, (7) and (8) in the graph indicate the temperature at the top of the 16-pin SOP and (8) at the top of the 64-pin QFP as shown in Table 4. The other parts (1) to (6) indicate the same parts as described above.
[0075]
[Table 4]

[0076]
As shown in FIG. 17 and Table 4, the temperature variation of each component has a large temperature variation both during preheating and during reflow heating. That is, in the first half of the preheating period, the upper part of the LED (6) and the upper part of the aluminum electrolytic capacitor (2), (5) having a small heat capacity are about 30 ° C. above the upper limit temperature (160 ° C.) While heated, QFP (1), (8) with large heat capacity has a slow rise speed and is lower than the temperature of circuit board (3), and it takes a long time to reach the lower limit temperature (150 ° C) of the preheating control temperature. Is needed.
In the second half of the reflow period, as with the heating pattern in the preheating period, the temperature rise speed is fast for the upper LED portion 6 and the aluminum electrolytic capacitor upper portions 2 and 5, and the solder melting management temperature is 210 to 220 ° C. The peak temperature reaches or exceeds the heat resistance limit temperature (240 ° C.) of the part. On the other hand, it takes a long time for the temperatures of QFP (1), (8) and PLCC (4) to reach the lower limit temperature (210 ° C.) of the solder melting management temperature. The maximum temperature difference ΔT of each part during the reflow period is about 40 ° C., and the temperature variation is large, and problems such as component failure and unmelted solder are likely to occur. Furthermore, since the heating to the circuit board 2 is uneven and unstable, the temperature difference between the boards is large.
[0077]
【The invention's effect】
  According to the present invention, when hot air is blown from a plurality of pipe nozzles toward a circuit board, a plurality of hot air blowing points by the pipe nozzle are dispersed in a plane with respect to the circuit board, thereby blowing the hot air to the circuit board. Uniform to the surface.
  In addition, after the blown hot air bounces off the circuit board, the hot air circulates in the furnace body through the flow path formed by the space between the arranged pipe nozzles, greatly reducing the hot air from enveloping. The hot air can be circulated efficiently without lowering the heat transfer efficiency.
  Furthermore, by making the pitch between each pipe nozzle row wider than the pitch between each pipe nozzle group, the path of hot air bounced off the circuit board can be surely secured, the circulation effect of hot air is improved, and the hot air stagnation Is further reduced.
  As described above, since the stagnation of hot air is reduced and the temperature variation of the circuit board can be reduced, a good reflow process can be performed even for lead-free solder.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of an entire reflow apparatus according to the present invention.
FIG. 2 is an overall perspective view of the reflow device showing a state in which an upper lid portion of the reflow device shown in FIG. 1 is opened.
FIG. 3 is an enlarged view of a reflow heating chamber of the reflow apparatus.
4 is a cross-sectional perspective view taken along the line AA in FIG. 3;
FIG. 5 is a partially enlarged perspective view of a hot air blowing portion.
FIG. 6 is a diagram showing a procedure for connecting a separator and a pipe nozzle.
FIG. 7 is a diagram showing a temperature profile for temperature control when passing through the first and second preheating chambers and the first and second reflow heating chambers.
FIG. 8 is a diagram illustrating a state in which hot air from an upper hot air blowing section is blown onto a circuit board to heat the circuit board.
FIG. 9 is a diagram showing a change in substrate temperature with respect to a reflow heating time when a circuit board using lead-free solder is subjected to a reflow process.
FIG. 10 is a view showing a configuration in which an infrared heater is provided between pipe nozzle groups of an upper hot air blowing portion as a modification of the reflow device according to the present invention.
FIG. 11 is a diagram showing a configuration in which a heat-resistant glass plate is provided on the lower side of the radiant heat heater.
FIG. 12 is a diagram showing a configuration in which an upper hot air blowing section is movably supported in a second modification of the reflow apparatus according to the present invention.
FIG. 13 is a view showing a configuration in which a pipe nozzle of an upper hot air blowing portion is fixed while being inclined with respect to a circuit board surface.
FIG. 14 is a diagram showing an arrangement of pipe nozzles in an upper hot air blowing section.
FIG. 15 is a view showing a configuration in which a shielding plate is provided at the tip of a pipe nozzle.
FIG. 16 is a diagram showing temperature changes of various electronic components on a circuit board with respect to reflow heating time.
FIG. 17 is a diagram showing a result of reflow processing performed by a reflow apparatus having upper and lower hot air blowing portions having conventional slit-like blowing ports corresponding to FIG. 15;
FIG. 18 is a view showing a reflow apparatus described in Japanese Patent Laid-Open No. 6-61640.
FIGS. 19A and 19B are diagrams showing a conventional hot air blowing method and stagnation of hot air at that time. FIG. 19A shows a case where hot air is blown by a fan, and FIG. 19B shows a case where hot air is blown by a slit-like hot air blowing nozzle. ing.
FIG. 20 is a view showing a reflow apparatus described in Japanese Patent No. 27872791.
FIG. 21 is a diagram for explaining the heat transfer efficiency from the conventional hot air to the circuit board and the response of the circuit board temperature to the hot air temperature.
[Explanation of symbols]
2 Circuit board
3 Electronic components
10 Substrate entrance
12 Substrate exit
14 Substrate transfer means
16 First preheating chamber
18 Second preheating chamber
20 First reflow heating chamber
22 Second reflow heating chamber
26 Sirocco fans
28 Heater
32 Upper hot air spraying part
34 Hot air suction part
37 Hot air outlet
38 Lower hot air blowing part
40 separator
42 Pipe nozzle
44 Pipe nozzle group
50 Infrared heater
52 Shield plate
54 Movement mechanism
100, 200, 300 reflow equipment

Claims (1)

A furnace body part, a substrate transport means for transporting a circuit board on which electronic components are mounted in the furnace body part, a hot air heating means for heating air in the furnace body, and hot air supplied from the hot air heating means A hot air spraying means comprising a plurality of pipe nozzles arranged at predetermined intervals, which is sprayed on the surface of the substrate;
By blowing hot air from the pipe nozzle of the hot air blowing means to the circuit board, a plurality of hot air blowing points are dispersed on the circuit board plane,
A reflow device for circulating hot air into a furnace through a flow path formed by a space between the arranged pipe nozzles after the blown hot air bounces off the circuit board ,
The hot air spraying means forms a plurality of pipe nozzle groups composed of a plurality of pipe nozzle rows in which the pipe nozzles are arranged in a direction substantially perpendicular to the substrate transport direction, and the pitch between the pipe nozzle groups in the substrate transport direction is set to each A reflow apparatus characterized in that it is wider than the pitch between pipe nozzle rows .

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