JP2005169403A - Reflow furnace for lead-free soldering, and temperature control method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that heat treatment suitable for lead-free soldering can not be performed in the conventional reflow furnace. <P>SOLUTION: In the reflow furnace for lead-free soldering and the temperature control method therefor, a reflow furnace for lead-free soldering is divided into five zones, respective work temperature control means are arranged adjacently to each other along the progressing direction of a work corresponding to each zone, the work is heated to about 150°C for 60 to 90 s, the work is heated at 150 to 170°C for 80 to 100 s, the work is heated to ≤233°C for 25 to 40 s, the work is held as it is for 20 to 25 s, and the work is cooled to about 110°C for 50 to 65 s. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a reflow furnace for lead-free soldering and a temperature control method thereof, and more particularly to a reflow furnace for soldering holes of a hole substrate and a temperature control method thereof.

A reflow furnace for controlling the temperature by applying hot air or cold air to a work for reflow soldering and its temperature control method are known (Patent Document 1).
JP-A-8-293666 (FIG. 1)

  However, the conventional method and apparatus cannot perform heat treatment suitable for lead-free solder.

  The present invention is intended to achieve such an object.

  The temperature control method of the reflow furnace for lead-free solder according to the present invention is such that the workpiece is gradually heated to approximately 150 ° C. in the first 60 to 90 seconds (first zone), and the workpiece is 150 to 170 ° C. in 80 to 100 seconds. (Second zone), and the workpiece is heated to a maximum of 233 ° C in 25 to 40 seconds (third zone), and maintained at the same temperature for 20 to 25 seconds (fourth zone), and in 50 to 65 seconds The workpiece is cooled to approximately 110 ° C. (fifth zone).

  The reflow furnace with lead-free solder according to the present invention comprises first to fifth workpiece temperature control means arranged along the moving direction of the workpiece, and the first one of the workpiece temperature control means is 60 to 90. The capacity to heat the workpiece to about 150 ° C in seconds, the second one to heat the workpiece from 150 ° C to 170 ° C in 80 to 100 seconds, and the third one to heat the workpiece in 25 to 40 seconds The capacity that can be heated up to 233 ° C, the fourth is the capacity that can maintain the temperature of the workpiece for 20 seconds to 25 seconds, and the fourth is that the workpiece is cooled to about 110 ° C in 50 seconds to 65 seconds. It is a thing to do.

  The work temperature control means has one and other side atmosphere temperature control units that are spaced apart from each other across the work path, and each of the one and other side units has a plurality of atmosphere outlets adjacent to each other. The unit is composed of a blowout opening having at least one and an atmosphere suction port arranged upstream and downstream of the blowout opening. It is characterized by being sucked by the mouth.

  According to the reflow furnace for lead-free soldering and the temperature control method thereof according to the present invention, lead-free soldering can be reliably and satisfactorily performed.

  Embodiments of the present invention will be described below with reference to the drawings.

  As a result of various experiments and researches, the present inventor needs to control the temperature of the work as shown in the graph of FIG. 1 when the work passes through the reflow furnace when lead-free solder containing no lead is used so as not to cause pollution. Turned out to be. Therefore, in the present invention, the workpiece is gradually heated to approximately 150 ° C. at a temperature rising rate of 3 ° C./second or less in the first 60 to 90 seconds as shown in FIG. Control the ball and presidge (first zone).

  In the next 80 to 100 seconds, the workpiece is heated to 150 ° C. to 170 ° C. (150 ° C. zone) as a preheating operation (second zone). If the preheating time is longer than this, it is not preferable because flux deterioration, solder balls due to powder oxidation and wetting defects occur.

  In the following 25 to 40 seconds, the heating temperature is increased and the workpiece is heated to a maximum of 233 ° C. and at least 227 ° C. (250 ° C. zone) (third zone) and maintained at the same temperature for 20 to 25 seconds (fourth zone). ). If this time exceeds 30 seconds, the wettability of the solder deteriorates, which is not preferable. Thereafter, the workpiece is cooled to approximately 110 ° C. for 50 to 65 seconds (fifth zone).

  In the lead-free soldered reflow furnace of the present invention, as shown in FIG. 2, the five workpiece temperature control means 6 to 10 are adjacent to each other along the traveling direction of the workpiece 17 corresponding to the zones 1 to 5. Arrange.

  For example, as shown in FIG. 3, each of the workpiece temperature control means 6 to 10 includes upper and lower atmosphere temperature control units 11 and 12 arranged vertically with a workpiece passage 18 interposed therebetween, as shown in FIGS. As shown in the figure, each of the upper unit 11 and the lower unit 12 is provided with, for example, a rectangular blowout opening 14 of 300 mm in width and 600 mm in length having a plurality of, for example, eight blowout openings 13 adjacent to each other. The mesh suction plate 16 is arranged on the upstream side and the downstream side of the blowing opening 14 respectively. Further, the interval between the openings 14 of the upper unit 11 and the lower unit 12 is set to, for example, 140 mm, which is approximately 20 mm larger than the conventional interval, and even when the workpiece 17 is not inserted, the blowout of each unit 11 or 12 is performed as shown in FIG. The atmosphere coming out of the mouth 13 is sucked by the atmosphere suction port 16 of the unit 11 or 12 respectively.

  Further, as shown in FIG. 5, a cold air introduction port 20 is provided in the hot air duct 19 for the air outlet 13 so that air having an arbitrary temperature obtained by mixing hot air and cold air can be blown out from the air outlet 13 as necessary. In addition, 21 is a heater, 22 is a cold air introduction duct, 23 is a cold air introduction valve, and 24 is a blower. Moreover, in FIG. 4, 25 is a heat insulating material.

  Furthermore, the workpiece temperature control means 6 has a capacity capable of heating the workpiece to approximately 150 ° C. at a rate of temperature increase of 3 ° C./second or less in 60 to 90 seconds, and the workpiece temperature control means 7 allows the workpiece to be heated in 80 to 100 seconds. The workpiece temperature control means 8 has a capacity capable of heating to a maximum of 233 ° C. and at least 227 ° C. in 25 to 40 seconds, and the workpiece temperature control means 9 has a capacity of 20 to 25 The capacity of the workpiece can be maintained as it is for a second, and the temperature control means 10 of the workpiece blows cooling air that cools the workpiece to approximately 110 ° C. for 50 to 65 seconds.

  There may be a plurality of temperature control means for each zone. Since the reflow furnace for lead-free soldering according to the present invention is configured as described above, the temperature of the workpiece can be controlled along the temperature control graph of FIG. 1, and lead-free soldering can be reliably and satisfactorily performed. .

It is a temperature control graph of the reflow furnace for lead-free soldering of this invention. It is a front view of the temperature control means of the reflow furnace for lead-free soldering of this invention. It is operation | movement explanatory drawing of the reflow furnace for lead-free soldering of this invention. It is a top view of the atmospheric temperature control means of the reflow furnace for lead-free soldering of this invention. It is explanatory drawing of the atmospheric temperature control means shown in FIG.

Explanation of symbols

1 zone 2 zone 3 zone 4 zone 5 zone 6 temperature control means 7 temperature control means 8 temperature control means 9 temperature control means 10 temperature control means 11 upper atmosphere temperature adjustment unit 12 lower atmosphere temperature adjustment unit 13 outlet 14 opening 15 network Plate 16 Atmosphere suction port 17 Work piece 18 Passage 19 Hot air duct 20 Cold air introduction port 21 Heater 22 Cold air introduction duct 23 Cold air introduction valve 24 Blower 25 Heat insulating material

Claims (3)

  The workpiece is gradually heated to approximately 150 ° C in the first 60 to 90 seconds (first zone), the workpiece is heated to 150 to 170 ° C (second zone) in 80 to 100 seconds (second zone), and the workpiece is heated in 25 to 40 seconds. Heat to a maximum of 233 ° C (3rd zone), maintain the temperature as it is for 20 to 25 seconds (4th zone), and cool the workpiece to about 110 ° C for 50 to 65 seconds (5th zone). A temperature control method for a reflow furnace for lead-free solder, which is characterized.   It consists of first to fifth workpiece temperature control means arranged along the direction of movement of the workpiece, and the first of the workpiece temperature control means has a capacity capable of heating the workpiece to approximately 150 ° C. in 60 to 90 seconds. The second is a capacity capable of heating the workpiece from 150 ° C. to 170 ° C. within 80 to 100 seconds, and the third is a capacity capable of heating the workpiece up to 233 ° C. within 25 to 40 seconds. Lead-free solder characterized in that No. 1 has a capacity capable of maintaining the workpiece temperature as it is for 20 seconds to 25 seconds, and No. 4 is for cooling the workpiece to approximately 110 ° C. in 50 seconds to 65 seconds. Attached reflow furnace.   The work temperature control means has one and other atmosphere temperature control units arranged spaced apart across the work path, and each of the one and other units has a plurality of atmosphere outlets adjacent to each other. And the atmosphere suction port arranged on the upstream side and the downstream side of the blowout opening, respectively, and the atmosphere that exits from the blowout opening of each unit even when no workpiece is inserted is the atmosphere suction port of the unit. The reflow furnace for lead-free soldering according to claim 2, wherein the reflow furnace is sucked by each of them.

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