JP2023115661A - Measuring method - Google Patents

Abstract

To measure a height of a liquid surface of jetted molten solder without visual confirmation of a scale by an operator.SOLUTION: A measuring method includes the steps of: a measurement step of measuring a first time B at which a temperature measured by a temperature sensor is a prescribed temperature or more by measuring, by the temperature sensor, a temperature of molten solder of a prescribed temperature or more, jetted upward from a nozzle while conveying a temperature measurement unit at a prescribed speed A using a conveying conveyor above a solder tank; a first calculation step of calculating a contact distance C in which the temperature sensor and the molten solder contact each other by C=A×B; and a second calculation step of calculating a height E of a liquid surface of the jetted molten solder by E=C×sinD when the contact distance C calculated in the first calculation step is smaller than a prescribed threshold level CT (where, D is an angle at which the conveying conveyor is obliquely installed on a horizontal surface, and E is a height of a liquid surface of the jetted molten solder).SELECTED DRAWING: Figure 3

Description

The present invention relates to a measuring method for jetting molten solder upward from a nozzle in a solder bath and measuring the liquid level of the jetting molten solder.

A jet soldering machine (also referred to as a flow soldering machine), for example, is used to electrically connect electronic components to predetermined positions on a printed wiring board by soldering in a flow manner. A jet soldering apparatus has a solder bath containing solder in a molten state (ie, molten solder).

The solder bath is provided with a pump for jetting molten solder upward. A nozzle is provided in the upper part of the pump, and the molten solder pressure-fed by the pump jets upward from the nozzle. Above the nozzle, a pair of belt conveyors are provided across the top opening of the solder bath.

The pair of belt conveyors are arranged with a slight inclination from the horizontal direction so that the conveying direction is obliquely upward with respect to the horizontal direction. A workpiece to be soldered is placed on the pair of belt conveyors, and is conveyed relatively slowly by the pair of belt conveyors.

The workpiece includes, for example, a printed wiring board and an electronic component having lead wires inserted into through-holes of the printed wiring board. When soldering a land and a lead wire in the vicinity of a through-hole on a workpiece by a flow method, flux is first applied to the lead wire, land, and the like.

Next, both ends of the printed wiring board are placed on a pair of belt conveyors and conveyed by the pair of belt conveyors. First, a printed wiring board or the like is heated to a predetermined temperature by a preheater, and then the printed wiring board or the like is further conveyed.

The height of the liquid level of the jetting molten solder oscillates in the vertical direction with the passage of time. , the molten solder enters the through-hole and adheres to the lead wire or the like.

After that, the soldering is completed by cooling and solidifying the molten solder. However, if the liquid level of the molten solder does not reach the predetermined height position, proper soldering cannot be performed. Therefore, in the jet soldering apparatus, the height of the jet molten solder is an important control item.

In order to measure the liquid level of jetting molten solder, it has been proposed to use a liquid level measuring device having three graduated heat-resistant glass plates arranged at regular intervals in a predetermined direction (for example, See Patent Document 1).

When measuring the height of the liquid level of jetted molten solder using this liquid level measuring device, the liquid level measuring device is transported by a pair of belt conveyors, and the molten solder reaching the opening between the adjacent graduated heat-resistant glass plates is measured. The height of the solder liquid level is visually measured using a scale.

A measuring jig has also been proposed in which a plurality of plate members are arranged in a stepped manner inside a hollow box-shaped housing with an open bottom surface (see, for example, Patent Document 2). While transporting this measuring jig on a pair of belt conveyors, visually confirming at what height the molten solder jetting into the box-shaped housing reaches the plate material, the liquid level of the jetting molten solder is measured. You can check the height of

JP-A-8-70175 JP 2011-189395 A

However, it is relatively difficult to measure the height of the liquid surface of the molten solder on the order of millimeters by visually checking the scale of the graduated heat-resistant glass plate or the plurality of plate materials arranged in a stepped pattern. Requires skill. In addition, if an inexperienced worker performs measurement, there is a possibility of making a measurement error.

SUMMARY OF THE INVENTION An object of the present invention is to measure the liquid surface height of jetted molten solder without visually confirming a scale by an operator.

According to one aspect of the present invention, there is provided a measuring method for jetting molten solder upward from a nozzle provided in a solder bath and measuring the height of the liquid surface of the jetting molten solder, wherein soldering is performed. A temperature measurement unit having a temperature measurement position set at a height corresponding to the lower surface of the workpiece to be processed and including a temperature sensor capable of measuring the temperature in contact with the molten solder is placed above the solder bath on a horizontal plane. an arrangement step of arranging the temperature measurement unit on a conveyer that can be conveyed in an inclined state with respect to the solder bath, and above the solder bath, while conveying the temperature measurement unit at a predetermined speed using the conveyer, upward from the nozzle A time corresponding to a contact time during which the temperature sensor is in contact with the molten solder is measured by the temperature sensor by measuring the temperature of the molten solder that has reached a predetermined temperature or higher. A measuring step of measuring a first time period during which the measured temperature is equal to or higher than the predetermined temperature; A is the predetermined speed at which the conveyer conveys the temperature measuring unit; A first calculation step of calculating a contact distance C between the temperature sensor and the molten solder by C=A×B, where B is 1 hour, and the contact calculated in the first calculation step When the distance C is smaller than the threshold C _T , the angle at which the transfer conveyor is inclined with respect to the horizontal plane is D, and the height of the liquid surface of the jetting molten solder is E, and the jetting molten solder is and a second calculation step of calculating the height E of the liquid level of the solder by E=C×sinD.

Preferably, when the contact distance C calculated in the first calculation step is equal to or greater than the threshold value C _T , the height of the molten solder jetted upward from the nozzle is adjusted to be lowered, and then the disposition is performed. A step, the measuring step and the first calculating step are sequentially performed.

In the measuring method according to one aspect of the present invention, the product of a predetermined speed A at which the conveyer conveys the temperature measurement unit and a first time B during which the temperature measured by the temperature sensor is equal to or higher than the predetermined temperature. Based on the calculated contact distance C, the liquid level E of the molten solder is calculated. Therefore, the height of the liquid surface of the molten solder can be measured without the operator visually confirming the scale.

It is a partial cross-sectional side view which shows the outline of a jet soldering apparatus. FIG. 2A is a top view of the temperature measurement unit, and FIG. 2B is a front view of the temperature measurement unit. It is a flow chart of a measuring method. It is a partial cross-sectional side view showing an arrangement step and the like. 4 is a graph showing an overview of temporal changes in temperature measured by a temperature sensor; FIG. 4 is a schematic diagram showing measurement steps; FIG. 7A is a diagram showing a case where the contact distance is smaller than the threshold, and FIG. 7B is a diagram geometrically showing the height of the liquid surface. FIG. 8A is a diagram showing a case where the contact distance is equal to or greater than the threshold, and FIG. 8B is a diagram geometrically showing the height of the liquid surface.

An embodiment according to one aspect of the present invention will be described with reference to the accompanying drawings. A jet soldering apparatus 2 shown in FIG. 1 is used to electrically connect a printed wiring board 13 and an electronic component 15 by supplying molten solder 11 to the lower surface side of a printed wiring board 13 by a flow method. .

In this embodiment, the printed wiring board 13 and the electronic component 15 in which the lead wires 15a of the electronic component 15 are inserted into the through holes 13a formed in the printed wiring board 13 are referred to as the workpiece 17. FIG.

Normally, the lower ends of the lead wires 15 a protrude slightly below the lower surface of the printed wiring board 13 . Soldering for electrically connecting a land in the vicinity of a through-hole 13a and a lead wire 15a by supplying jetted molten solder 11 to a lower surface 17a side of a workpiece 17 using a jet soldering device 2. is done.

FIG. 1 is a partial cross-sectional side view showing an outline of a jet soldering apparatus 2. FIG. In FIG. 1, the X-axis direction, Y-axis direction and Z-axis direction are orthogonal to each other. The XY plane corresponds to the horizontal plane and the Z-axis direction corresponds to the vertical direction.

In FIG. 1, a fluxer (that is, a solder flux applicator) for applying flux to the printed wiring board 13, the lead wires 15a and the like, and a fluxer for cooling the printed wiring board 13 and the like after supplying the molten solder 11 to the workpiece 17 are provided. A cooling device is omitted.

The molten solder 11 is a so-called lead-free solder such as Sn--Ag--Cu solder, and melts at about 220.degree. However, as long as it is lead-free solder, it is not limited to Sn--Ag--Cu solder, and other types of solder may be used.

When performing soldering, the workpiece 17 is placed on a pair of belt conveyors (conveyance conveyors) 4a and 4b (see FIG. 2A) provided in the jet soldering apparatus 2. As shown in FIG. As shown in FIG. 2(A), the pair of belt conveyors 4a and 4b are arranged apart from each other by a predetermined distance in the Y-axis direction, and a gap 4c is formed to allow the jetting molten solder 11 to rise. .

As shown in FIG. 1, the pair of belt conveyors 4a and 4b are arranged at a predetermined angle D (for example, 3 degrees or more and 5 degrees or less).

The pair of belt conveyors 4a and 4b are driven by a drive source (not shown) such as a motor. It is transported at a predetermined speed A (for example, approximately 1.0 m/min) while being inclined by an angle D.

On the other hand, when the pair of belt conveyors 4a and 4b are arranged substantially parallel to the horizontal direction, the molten solder 11 adhering to the lead wire 15a jumps as the lead wire 15a is conveyed and adheres to the other lead wire 15a. Problems such as bridges that do not occur.

However, by inclining the pair of belt conveyors 4a and 4b with respect to the horizontal direction by a predetermined angle D, it is possible to suppress the occurrence of defects such as bridging.

A preheater 6 for raising the temperature of the printed wiring board 13, lead wires 15a, etc. to a first temperature (for example, about 110° C. to 160° C.) suitable for soldering is provided on the front side in the transport direction 4e. . The preheater 6 has a prismatic housing 6c with an inlet 6a and an outlet 6b.

A plurality of heaters 6d arranged at predetermined intervals along the X-axis direction are arranged on the bottom side of the housing 6c. A plurality of heaters 6d are positioned below the gap 4c (see FIG. 2A) between the pair of belt conveyors 4a and 4b. Each heater 6d has, for example, an infrared lamp, and heats the printed wiring board 13 passing above.

By performing preheating with the preheater 6, the excess solvent contained in the flux can be volatilized. In addition, it is possible to prevent deterioration of the printed wiring board 13 and the like due to a rapid temperature change that occurs when the printed wiring board 13 comes into contact with the molten solder 11 without preheating.

A solder bath 8 containing molten solder 11 is arranged below the pair of belt conveyors 4a and 4b and further on the back side than the preheater 6 in the conveying direction 4e. The solder bath 8 is provided with a heater (not shown) for heating solder.

The heater heats the solder to a temperature higher than a second temperature (predetermined temperature, for example, 220° C.) at which the solder melts, and heats the molten solder 11 to a temperature higher than the second temperature (for example, a temperature suitable for flow soldering). 260° C.).

Also, the solder bath 8 is provided with a first pump 10 . The first pump 10 is, for example, a screw pump having a screw to which power is transmitted from the output shaft of the motor via a belt, but it may also be an electromagnetic induction pump.

A first nozzle 12 is provided above the first pump 10 . The first nozzle 12 has a plurality of openings 12a formed in a predetermined arrangement in the X-axis direction and the Y-axis direction. The molten solder 11 pressure-fed to the first nozzle 12 by the first pump 10 jets upward from each opening 12a.

By jetting the molten solder 11 from each opening 12a (that is, in the primary jet), the workpiece 17 is relatively roughly soldered. The molten solder 11 that has not adhered to the workpiece 17 returns to the solder bath 8 and is then jetted upward again by the first pump 10 .

A second pump 14 is provided behind the first pump 10 in the transport direction 4e. The second pump 14, like the first pump 10, is a screw pump or an electromagnetic induction pump. A second nozzle 16 is provided above the second pump 14 .

The second nozzle 16 has one opening 16a that is larger in size than the one opening 12a. The molten solder 11 pressure-fed by the second pump 14 jets upward from the opening 16a.

By jetting the molten solder 11 from the opening 16a (that is, in the secondary jet), a fillet is formed at the soldered location. The jetted molten solder 11 returns to the solder bath 8 and is then jetted upward again by the second pump 14 .

The workpiece 17 conveyed at a predetermined speed A by the pair of belt conveyors 4a and 4b above the solder bath 8 is sequentially soldered by the first nozzle 12 and the second nozzle 16, and then cooled by the cooling device ( not shown).

As described above, the height 11b of the liquid surface 11a of the jetted molten solder 11 is an important control item. As shown in FIG. 1, the height 11b of the liquid surface 11a in the primary jet is defined, for example, by the distance from the upper surface 4d to the liquid surface 11a in the direction orthogonal to the upper surface 4d.

In this embodiment, the height 11b of the liquid surface 11a of the molten solder 11 is measured using the temperature measurement unit 20 (see FIG. 2A, etc.) according to the measurement method shown in FIG. Therefore, first, the temperature measurement unit 20 will be described.

FIG. 2A is a top view of the temperature measurement unit 20. FIG. The temperature measurement unit 20 has a rectangular parallelepiped housing 22 made of metal such as stainless steel. Both sides of the housing 22 are provided with legs 22a.

The pair of legs 22a are placed on the upper surfaces 4d of the pair of belt conveyors 4a and 4b, like the workpiece 17. As shown in FIG. A bottom plate 22b of the housing 22 is provided above the leg portion 22a. A temperature sensor 24 is provided on the bottom plate 22b.

FIG. 2B is a front view of the temperature measurement unit 20. FIG. The temperature sensor 24 of this embodiment has a hook-shaped probe 26, as shown in FIG. 2(B). The probe 26 has a sheath formed of a metal tube such as stainless steel and fixed in position with respect to the housing 22 .

The sheath has a proximal end 26a arranged to extend substantially parallel to the bottom plate 22b. The intermediate portion 26b of the sheath is arranged along the height direction 22c of the housing 22 so as to be bent from the tip of the base end portion 26a. The intermediate portion 26b passes through a through hole _22b1 formed in the bottom plate 22b.

Further, the distal end portion 26c of the sheath is arranged substantially parallel to the proximal end portion 26a so as to be bent from the distal end of the intermediate portion 26b. Note that the base end portion 26 a and the tip end portion 26 c are arranged along the width direction 22 d of the housing 22 .

A thermocouple is positioned within the sheath. In this embodiment, a K-type thermocouple is arranged, but other types of thermocouples may be used. A temperature measuring junction 26d of the thermocouple is located on the distal end side of the distal end portion 26c, but is covered with the sheath without being exposed from the sheath.

The tip portion 26c may be a grounded type in which the temperature measuring junction 26d contacts the inner wall of the sheath, or may be a non-grounded type in which the temperature measuring junction 26d does not contact the inner wall of the sheath. As indicated by the dashed line in FIG. 2(B), in the height direction 22c of the housing 22, the tip portion 26c is positioned substantially at the same position as the bottom surface of the foot portion 22a.

When the housing 22 is placed on the upper surface 4d of the pair of belt conveyors 4a and 4b, the tip 26c of the probe 26 is arranged at a height corresponding to the lower surface 17a of the workpiece 17. As shown in FIG. The height corresponding to the lower surface 17a means, for example, the same height as the lower surface 17a.

However, the fact that the tip portion 26c is arranged at a height corresponding to the lower surface 17a includes that the tip portion 26c is arranged with a deviation of within 2 mm from the height position of the lower surface 17a, and more preferably within 1 mm. Arrangement with deviation is also included.

The tip portion 26c may be arranged at the same position as the lower surface of the printed wiring board 13 or at the same position as the lower end of the lead wire 15a. It may be arranged at a position corresponding to a position in between.

The position of the tip portion 26c in the height direction 22c is the temperature measurement position in the temperature measurement unit 20. As shown in FIG. The temperature of the jetting molten solder 11 is measured by contacting the tip portion 26 c with the molten solder 11 .

In particular, by arranging the tip portion 26c so as to be perpendicular to the Z-axis direction and the conveying direction 4e, the tip portion 26c can be stably brought into contact with the liquid surface 11a of the jetted molten solder 11 . Therefore, the temperature of the jetting molten solder 11 can be stably measured.

On the bottom plate 22b, a housing 28 having a double structure of an outer wall made of iron and an inner wall made of heat insulating material such as refractory fiber or noncombustible cotton is provided. As shown in FIG. 2A, a predetermined circuit 32 electrically connected to the probe 26 via wiring 30 is provided inside the housing 28 .

The predetermined circuit 32 includes an amplifier circuit that amplifies the electrical signal indicating the temperature and a temperature compensation circuit that corrects the temperature of the reference junction of the thermocouple. Certain circuits 32 are electrically connected to certain systems 34 located within housing 28 .

The predetermined system 34 includes a control IC (Integrated Circuit), a substrate having an input/output port, etc., and a memory storing predetermined software. The predetermined system 34 is configured using, for example, ARDUINO (registered trademark), which is a type of one-board microcomputer.

Power is supplied to a given system 34 and a given circuit 32 from a power supply section 36 located within the housing 28 . Power supply 36 includes one or more batteries. An opening (not shown) is formed in each of the top plate portions of the housings 22 and 28 so as to be openable and closable.

When operating the temperature measurement unit 20 , the operator opens the opening of each top panel and turns on a power switch (not shown) provided on a board of a predetermined system 34 . However, an antenna or the like may be provided on the board of the predetermined system 34, and the power switch may be switched on/off by a wireless method.

Next, a measuring method for measuring the height 11b of the liquid surface 11a of the jetted molten solder 11 will be described with reference to FIG. FIG. 3 is a flow chart of the measuring method. First, the temperature measurement unit 20 is placed on the pair of belt conveyors 4a and 4b (placement step S10).

FIG. 4 is a partial cross-sectional side view showing the placement step S10 and the like. Note that FIG. 4 shows the probe 26 by cutting out part of the housing 22 .

In the placement step S10 of the present embodiment, the temperature measurement unit 20 is placed on the front side of the preheater 6 in the transport direction 4e, and the temperature measurement unit 20 is moved at the same predetermined speed A as when soldering the workpiece 17. transport.

The transportation at the predetermined speed A is continued until the flow of the measuring method ends. After the placing step S10, the temperature measuring unit 20 is heated at the same first temperature as when heating the workpiece 17 (preheating step S20).

By performing preheating in the same manner as when soldering the workpiece 17 using the jet soldering apparatus 2, the same conditions as when actually soldering the tip portion 26c of the probe 26 can be obtained. Reproducible.

After the preheating step S<b>20 , the temperature sensor 24 measures the temperature of the molten solder 11 jetted upward from the first nozzle 12 while the temperature measurement unit 20 is being transported. The temperature of the jetted molten solder 11 is equal to or higher than the second temperature (for example, 260° C.).

As the temperature measurement unit 20 advances in the conveying direction 4e, the tip 26c of the probe 26 sequentially contacts the molten solder 11 jetted from the first nozzle 12 and the molten solder 11 jetted from the second nozzle 16. .

FIG. 5 is a graph showing an overview of temporal changes in temperature measured by the temperature sensor 24. As shown in FIG. The horizontal axis indicates time, and the vertical axis indicates temperature (°C). The temperature T1 is the temperature of the environment in which the jet soldering apparatus 2 is placed, for example, room temperature (approximately 20° C. in one example).

A temperature T2 is a first temperature (for example, about 110° C. to 160° C.) measured by the temperature sensor 24 when the preheater 6 preheats the temperature measurement unit 20 . A temperature T3 is a temperature measured by the temperature sensor 24 when the temperature sensor 24 comes into contact with the molten solder 11, and is a temperature equal to or higher than the second temperature (for example, 260° C.±1.5° C.).

In the time region R1 in which the temperature T3 is maintained for the first time, the tip portion 26c is in contact with the molten solder 11 jetted from the first nozzle 12 while the temperature measured by the temperature sensor 24 is the temperature T3. Corresponds to contact time U1.

Next, in the time region R2 in which the temperature T3 is maintained, similarly, the tip portion 26c is in contact with the molten solder 11 jetted from the second nozzle 16 while the temperature measured by the temperature sensor 24 is the temperature T3. It corresponds to the contact time U2 that is held.

In this embodiment, the case of measuring the contact time U1 (that is, the first time B) will be described as the measurement step S30, but the same description applies to the case of measuring the contact time U2 in the measurement step S30. Therefore, description of the case of measuring the contact time U2 is omitted.

FIG. 6 is a schematic diagram showing the measurement step S30. However, in FIG. 6, the shape of the liquid surface 11a of the molten solder 11 jetted from the first nozzle 12 approximates a rectangular shape in the XZ plane. Note that FIG. 6 also shows the probe 26 by cutting out part of the housing 22 .

The reason for the approximation to a rectangle is that the highest position of the height of the liquid surface 11a and the width in the X-axis direction of the liquid surface 11a that crosses the pair of belt conveyors 4a and 4b on the XZ plane are two factors that are different from the flow method. This is because it is considered to be a major parameter in soldering.

In general, the higher the height of the liquid surface 11a of the molten solder 11 in the Z-axis direction, the larger the width 11c of the liquid surface 11a in the X-axis direction (see FIG. 7A). The lower the height in the Z-axis direction, the smaller the width 11c of the liquid surface 11a in the X-axis direction.

By the way, in this embodiment, the height E of the liquid surface 11a in the direction perpendicular to the upper surface 4d (that is, the height 11b in FIGS. 1 and 4) is treated as the height of the liquid surface 11a of the jetted molten solder 11. Since the predetermined angle D with respect to the horizontal direction is very small, 3 degrees or more and 5 degrees or less, the height of the liquid surface 11a in the Z-axis direction substantially corresponds to the height E of the liquid surface 11a in the direction orthogonal to the upper surface 4d. do.

In this embodiment, first, the contact distance C (indicated by the thick line in FIG. 6) between the molten solder 11 reaching the upper surface 4d and the temperature sensor 24 in the conveying direction 4e is calculated as the product of the predetermined speed A and the first time B. (That is, it is calculated by Equation 1) (first calculation step S40).

Next, it is determined whether or not the contact distance C calculated in the first calculation step S40 is smaller than the threshold value _CT (determination step S50). The threshold C _T is predetermined according to the output of the first pump 10 (for example, the rotation speed of the screw).

The output of the first pump 10 is determined, for _example , so that the width 11c of the liquid surface 11a in the X-axis direction is a predetermined value of 20 mm to 30 mm. (that is, C _T =(width 11c)/cosD) (see FIG. 7A).

FIG. 7A is a diagram showing a case where the contact distance C is smaller than the threshold C _T (C<C _T ), and FIG. 7B is a diagram geometrically showing the height E of the liquid surface 11a. is. For convenience, the threshold C _T is indicated by a thick line in FIG. Further, in FIGS. 7A and 7B, the contact distance C is also indicated by a thick line.

As shown in FIG. 7B, the height F of the liquid surface 11a in the Z-axis direction and the height E in the direction orthogonal to the upper surface 4d are as follows when referring to a right-angled triangle with the height F as the hypotenuse: (E/F=cosD) is satisfied.

Here, the angle D is sufficiently small that cosD can be approximated to 1 (ie cosD≈1). Therefore, height F can be approximated to height E (F≈E).

Further, referring to the right triangle with the contact distance C as the hypotenuse, the height F is given by the product of the contact distance C and sinD (F=C*sinD). Therefore, the height E is calculated by the product of the contact distance C and sinD (that is, Equation 2) (second calculation step S60).

Thus, in this embodiment, the height E of the liquid surface 11a of the molten solder 11 can be measured in the flow method without the operator visually checking the scale.

If the height E is not suitable for soldering, the output of the first pump 10 (for example, the rotation speed of the screw) is increased within a range in which the contact distance C is smaller than the threshold value _CT . E may be increased.

By the way, the calculations of Equations 1 and 2 may be performed by an operator or by a computer. In one example, a computer functioning as a control unit of the jet soldering apparatus 2 performs the calculations of Equations 1, 2, and the like.

A computer includes a processor (processing device) represented by a CPU (Central Processing Unit), a main memory, and an auxiliary memory. Note that an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or the like may be used instead of the CPU.

The main storage device includes DRAM (Dynamic Random Access Memory), SRAM (Static Random Access Memory), ROM (Read Only Memory) and the like, and the auxiliary storage device includes flash memory, hard disk drive, solid state drive and the like.

Software including a predetermined program is stored in the auxiliary storage device. By executing this predetermined program on the processing device, calculations such as Equation 1 and Equation 2 can be executed.

More specifically, the auxiliary storage device pre-stores the predetermined speed A, the threshold value C _T and the angle D, and additionally stores the first time B obtained in the measurement step S30. Then, the computer calculates the contact distance C according to Equation 1, and then calculates the height E according to Equation 2 when the contact distance C is smaller than the threshold value C _T (YES in S50).

However, if the contact distance C is greater than or equal to the threshold _CT in the determination step S50, Equation 2 does not work. FIG _. 8A shows the case where the contact distance C is equal to or greater than the threshold _CT , and FIG. It is a schematic diagram.

In FIGS. 8A and 8B, the contact distance C and the threshold C _T are also indicated by thick lines. As shown in FIGS. 8A and 8B, when the contact distance C is equal to or greater than the threshold _CT , the height F of the liquid surface 11a in the Z-axis direction is expressed by Equation (3).

However, the height Δ in Equation 3 cannot be measured using the temperature measurement unit 20 . Therefore, the output of the first pump 10 (for example, the rotation speed of the screw) is lowered so as to lower the height E of the jetted molten solder 11 (liquid level height adjustment step S70).

After adjusting the first pump 10 in this manner, the placement step S10, the preheating step S20, the measurement step S30, and the first calculation step S40 are sequentially performed again. If the contact distance C is smaller than the threshold _CT (YES in S50), the process proceeds to the second calculation step S60.

On the other hand, if the contact distance C is still equal to or greater than the threshold _CT even after the liquid level height adjustment step S70 (NO in S50), the liquid level height adjustment step S70 is performed again.

As described above, in this embodiment, the contact time U1 between the tip portion 26c of the probe 26 and the liquid surface 11a of the molten solder 11 is measured using the temperature measuring unit 20 conveyed at the predetermined speed A. , the height E of the jetting molten solder 11 can be measured.

Therefore, the operator can measure the height E of the liquid surface 11a of the molten solder 11 without visually confirming the scale. In addition, the structures, methods, and the like according to the above-described embodiments can be modified as appropriate without departing from the scope of the present invention.

For example, for the molten solder 11 jetted from the second nozzle 16, the height E of the liquid surface 11a can be similarly measured and adjusted according to the measuring method shown in FIGS. 3 to 8B. That is, the height E of the liquid surface 11a may be measured and adjusted for either or both of the first pump 10 and the second pump 14 .

The output of the second pump 14 is determined, for example, so that the width 11c of the liquid surface 11a in the X-axis direction is approximately 50 mm, and the threshold _CT is calculated by dividing the width 11c by cosD.

2: jet soldering device, 4a, 4b: belt conveyor (transport conveyor)
4c: Gap 4d: Upper surface 4e: Conveyance direction 6: Preheater 6a: Inlet 6b: Outlet 6c: Housing 6d: Heater 8: Solder bath 10: First pump 12: First nozzle 12a : opening 11: molten solder 11a: liquid surface 11b: height 11c: width 13: printed wiring board 13a: through hole 15: electronic component 15a: lead wire 14: second pump 16: second Nozzle 16a: Opening 17: Work piece 17a: Lower surface 20: Temperature measurement unit 22: Housing 22a: Foot portion 22b: Bottom plate 22b ₁ : Through hole 22c: Height direction 22d: Width direction 24: temperature sensor 26: probe, 26a: proximal end, 26b: intermediate portion, 26c: distal end, 26d: temperature measuring junction 28: housing, 30: wiring, 32: circuit, 34: system, 36: power supply A: predetermined speed, B: first time, C: contact distance, C _T : threshold D: angle, E: height, F: height, Δ: height R1: time domain, R2: time domain, U1 , U2: contact time, T1, T2, T3: temperature S10: placement step, S20: preheating step, S30: measurement step S40: first calculation step, S50: determination step S60: second calculation step, S70: liquid level height adjustment step

Claims (2)

A measuring method for jetting molten solder upward from a nozzle provided in a solder bath and measuring the height of the liquid surface of the jetting molten solder, comprising:
a temperature measuring unit having a temperature measuring position set at a height corresponding to the lower surface of a workpiece to be soldered and including a temperature sensor capable of measuring temperature by contacting the molten solder; an arrangement step of arranging on a transport conveyor that can be transported in a state inclined with respect to the horizontal surface above the
Above the solder bath, the temperature sensor measures the temperature of the molten solder jetting upward from the nozzle and reaching a predetermined temperature or higher while conveying the temperature measuring unit at a predetermined speed using the conveyer. By doing so, the temperature sensor measures a first time corresponding to the contact time during which the temperature sensor is in contact with the molten solder and the temperature measured by the temperature sensor is equal to or higher than the predetermined temperature. a step;
A contact distance between the temperature sensor and the molten solder, where A is the predetermined speed at which the conveyer conveys the temperature measurement unit, and B is the first time measured in the measurement step. A first calculation step of calculating C by C=A×B;
When the contact distance C calculated in the first calculation step is smaller than the threshold value _CT , the angle at which the transfer conveyor is inclined with respect to the horizontal plane is defined as D, and the liquid surface of the jetted molten solder is A second calculation step of calculating the height E of the liquid surface of the jetted molten solder by E=C×sinD, where E is the height of
A measuring method comprising: When the contact distance C calculated in the first calculation step is equal to or greater than the threshold value C _T , the height of the molten solder jetted upward from the nozzle is adjusted to be lowered, and then the disposing step, the 2. The measuring method according to claim 1, wherein the measuring step and the first calculating step are performed sequentially.

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