JP4012920B2 - Lead-free flux-containing solder bus manufacturing method and manufacturing apparatus - Google Patents

Description

  The present invention relates to a lead-free flux-containing solder bus bar manufacturing method and the manufacturing apparatus.

  In 1974, the Convention on the Prevention of Marine Pollution by Disposing of Waste (London Convention) and in 1989 the Convention on the Cross-border Movement of Hazardous Waste (Basel Convention) were signed. The EU Directive on Disposal (WEEE + RoHS) is scheduled to implement regulations on the use of hazardous chemical substances (RoHS), and heavy metals (lead, mercury, cadmium, hexavalent chromium), PBB, and PBDE are targeted. When the lead-containing solder is switched to the lead-free solder, the physical properties naturally change greatly, and a technology corresponding to the change is required.

  In the production of flux-cored linear solder, in addition to the study of lead-free materials, the flux is also studied, and further improvements in the method of producing linear solder are desired.

  The flux that is indispensable for soldering has changed greatly corresponding to lead-free.

As the flux conditions, the following are generally required.
(1) It must be chemically active in order to remove the base material and the solder surface oxide film.
(2) The wettability and fluidity of the flux itself with respect to the base material are good.
(3) It has a covering property to prevent the base material from being oxidized in the soldering process.
(4) Thermal stability that maintains the activity without decomposition at the soldering temperature.
(5) Flux residue can be easily removed.
(6) Harmless to human body and equipment and economical.

In order to support lead-free, in addition to the above-mentioned flux conditions, <1> improved thermal stability to withstand higher temperatures in the die during linear solder manufacturing (during cold extrusion molding) and at higher temperatures Reduction of volatile matter from flux to prevent flux breakage due to gas generation in
<2> When soldering with lead-free solder, the soldering temperature will be higher than that with lead solder, so the flux will remain at the soldering site for the time required for flux oxidation prevention and oxide film removal. It is necessary to increase the viscoelasticity at that temperature so that it can exist and so that the flux gas pressure does not increase and the flux scatters.

  In the past, the flux for lead solder used pine resin itself, and there was almost no corrosion due to residues, and the action was slow.

  A mixture of the following components has been proposed as one of the current lead-free fluxes.

  (1) Rosin, rosin derivative as base resin, (2) Diethylene glycol, glycol ether as solvent, (3) Hydrohalic acid amine salt, organic acid (stearic acid etc.), amine (triethanolamine) as activator Etc.), (4) castor wax and carnauba wax as thixotropic agents, and (5) double bond-containing substances as quenching agents.

  Factors that affect the manufacturing efficiency of flux-cored solder buses include a stable bus bar manufacturing speed and a flux breakage prevention method.

  In the cold extrusion molding method in the flux-cored solder bus manufacturing method, when switching the “solder” billet that has been cast and shaped to a predetermined size as the bus bar material, the manufacturing speed has to be reduced, and in general extrusion molding Because the flux is switched by stopping the machine, and because of the uncertain flux supply method, flux is not injected at the joint at the time of addition and switching, and flux breaks are likely to occur. This has been dealt with by cutting in advance the expected flux breakage point.

  Establishing a method that can follow the flux injection without interruption during billet switching and a method that can confirm this will not only reduce or eradicate the current loss, but also reduce the man-hours for loss cutting.

In order to greatly improve the basic unit of expensive lead-free solder that cannot simply be recycled,
(1) It is necessary to suppress as much as possible the volatile matter that becomes a gas in a die in which the flux inserted into the continuous hole portion opened at the center of the solder bus bar has a higher temperature than that for lead solder. (2) The amount of flux entering the solder hole from the flux tank per unit time is equal to the amount of flux in the solder bus calculated from the manufacturing amount per unit time of the solder bus. In order to be able to confirm this, a technique capable of detecting the liquid level of the molten flux in the flux tank and its change is required.

As a prior art of the manufacturing method, a manufacturing method of flux-cored wire solder from difficult-to-work solder: “A long and thin thin plate solder having a groove into which flux is put in the length direction from the difficult-to-work solder is formed, and flux is put into the groove. Thus, an invention of forming a flux-cored wire solder is disclosed (for example, see Patent Document 1).
JP 2001-96395 A

  However, in the case of Patent Document 1, it is obtained by forming a thin plate solder provided with a large number of grooves into which flux is poured from a solder material, and cutting the thin plate solder into a strip shape. The problem remains.

  The present invention has been made in view of the above circumstances. (1) A flux for lead-free solder melted to a temperature at which necessary fluidity can be obtained with a flux supply device attached to a solder bus cold extrusion molding machine. Fully deaerated under conditions (temperature, degree of vacuum) that do not block the deaeration line due to bump entrainment, (2) Open hole in the center of the solder bus bar during extrusion molding The molten flux after deaeration is forcibly injected so that flux breakage does not occur, the fluctuation of the liquid level of the flux tank during injection is detected, and the calculation result of the flux consumption agrees with the detection result of the bus manufacturing speed, It is an object of the present invention to provide a lead-free flux-containing solder bus bar manufacturing method and a manufacturing apparatus without flux breakage.

  This invention can solve the said subject by providing the following structure.

  (1) In a lead-free flux-containing solder bus manufacturing method having a flux supply device and an extrusion molding machine, a heating step of heating the flux with a heater provided on the outer periphery of the tank for imparting fluidity to the flux in the flux tank Then, the degassing on-off valve is opened with the timer switch ON, the exhaust means is operated, and the air in the molten flux and the upper surface of the molten flux in the flux tank and the air in the molten flux are maintained while maintaining the deaerated state immediately before the bumping limit. A deaeration process for degassing, an exhaust means stop process for stopping the exhaust means with a timer switch OFF after deaeration for a predetermined time, and a level detection means for detecting the molten flux liquid level with the deaeration on-off valve opened. And a plunger that operates through a plug position detecting means that cooperates with a plunger for vertical movement and a connecting member that is connected to the plunger. The float part of the sensor on-off valve with a float part that lowers the pressure press-fit plug and opens and closes the sensor part provided below the tip sensor part of the level detection means contacts the liquid level of the molten flux. When the sensor is opened, the sensor opening / closing valve opens, and then, when the sensor section is immersed in the liquid of the molten flux, a thermoelectromotive force is generated, and the action of the thermoelectromotive force causes the deaeration opening / closing valve via the electromagnetic switch. A deaeration stop process that closes and stops the deaeration operation, and a flux press-fitting plug that moves up and down in conjunction with the level detection means and the plug position detection means, pushes down the deaerated flux at a predetermined speed, and lowers it downward A flux injection step of forcibly injecting into a hole opened in the center portion of the solder bus bar during extrusion molding through the connecting flow path and the flux injection nozzle; A calculation step of determining whether a comparison calculation result of the consumption amount of the flux in the fixed time and the consumption amount of the flux injected into the solder bus at the same time is within a predetermined range; A method for producing a lead-free flux-filled solder bus having the following:

  (2) In the deaeration step, the deaeration passage is heated in order to prevent the deaeration passage from being blocked by condensation / adherence of vapor contained in the air being deaerated. Solder bus manufacturing method with lead-free flux.

  (3) A plurality of preliminary devices having the same specifications as the flux supply device described in the preceding paragraph (1) are provided, and a temperature range for maintaining required fluidity and a deaeration passage are provided during operation of the flux supply device in use. A lead-free flux-filled solder bus manufacturing method capable of maintaining a deaeration state immediately before the limit of bumping occurrence and capable of deaeration to an allowable volatile content with a vacuum level that does not block due to entrainment .

(4) A lead-free flux-containing solder busbar manufacturing apparatus including a flux supply device including a flux tank, a flux press-fit plug, a flux level detection means, a deaeration mechanism, and a plug position detection means,
The flux tank has a lid that is detachably fixed, and a heater for imparting fluidity to the flux is provided on the outer peripheral surface of the tank so that flux can be stored and supplied. The flux in the flux tank is sent and supplied via a plunger portion that is suspended from the plug support rod and can be moved up and down in conjunction with an arm portion that is connected to the plug support rod. The flux can be continuously injected into the longitudinal center of the solder bus bar through the passage and the flux injection nozzle, and the valve body of the deaeration on-off valve is suspended and fixed to the lower part of the valve body support rod. A double cylinder body with a cooling function is inserted through the valve body of the deaeration on-off valve, and a sensor on-off valve with a float is provided at the tip of the double cylinder body, and the tip of the double cylinder body is inserted through the sensor on-off valve. Come on, said Float of capacitors off valve is opened is the sensor-off valve by the action of the float portion when in contact with the flux liquid surface and a level detecting means for detecting a flux liquid surface,
The heating means provided around the inner peripheral surface of the plug support rod, the annular gap forming the degassing passage on the inner surface side of the plug support rod and inside the heating means, and the degassing passage as a boundary. A plug body is suspended and fixed via an annular valve seat at the lower end of a plug support rod that moves up and down via a sliding ring inserted and fitted in the lid portion, and is engaged with the annular valve seat and the annular valve seat. It has a deaeration mechanism consisting of an open / close valve body for degassing that can be freely fitted and removed.
The plug position detecting means moves up and down in conjunction with the plug body and the plug support rod, and consumes the flux in the flux tank for a certain time and within a certain time for the flux injected into the solder bus at the same timing. A lead-free flux-containing solder bus manufacturing apparatus comprising: calculating means for determining whether or not a result of comparison with the consumption amount is within a predetermined range.

  (5) The level detection means is composed of a thermocouple having corrosion resistance, and the thermocouple is accommodated in a double cylinder having an air jacket, and the double cylinder is inserted and fixed in the deaeration on-off valve body. (4) The above item (4) is provided with a cylindrical valve body supporting rod which is suspended and fixed to the outside and can be moved up and down together with the deaeration on-off valve body, and is surrounded by the deaeration passage. Solder bus manufacturing equipment with lead-free flux as described in 1.

  (6) The deaeration mechanism has a plurality of exhaust means shared by the flux supply devices, and the flux that is heated to a predetermined temperature and has fluidity maintains the deaeration state just before the bumping occurrence limit, A degassing on-off valve for degassing the liquid upper surface gap of the flux and air in the flux, the degassing on-off valve senses the thermoelectromotive force generated by the thermocouple, and moves upward, The lead-free flux-containing solder bus bar manufacturing apparatus according to (4), wherein the degassing passage is closed.

  The lead-free solder flux that has been melted to the temperature at which the required fluidity can be obtained with the flux supply device attached to the solder bus cold extrusion molding machine will not cause the entrainment of the bumping state and block the deaeration passage. Fully deaerate under conditions (temperature, degree of vacuum), and forcibly inject the molten flux after deaeration into the open hole in the center part during extrusion of solder bus bar so that flux breakage does not occur and injecting Flux tank liquid level fluctuation is detected, and the calculation result of the flux consumption matches from the detection result of the bus manufacturing speed, and the lead-free flux-containing solder bus bar manufacturing method and the manufacturing apparatus can be provided. The loss rate of lead-free solder, which is more expensive than lead solder, can be greatly reduced.

  Embodiments of a lead-free flux-containing solder bus manufacturing method and the manufacturing apparatus according to the present invention will be described below.

  FIG. 1 is a flowchart showing an example of a lead-free flux-filled solder bus manufacturing method according to the present invention, FIG. 2 is a block diagram showing a main part configuration, and (a) is a block diagram showing a series of main elements. (B) is a block diagram showing the system configuration, FIG. 3 is a partially broken side view showing the configuration of the main part of the flux supply device, FIG. 4 is a detailed sectional view of the main part, and FIG. 5 is the main part showing the operation. Cross-sectional view, (a) is a cross-sectional view of the main part showing the initial state, (b) is a cross-sectional view of the main part showing the state at the start of deaeration, and FIGS. 6 (a) and 6 (b) are intermediate steps after the start of operation. 7 is a cross-sectional view of the main part showing a state in which the flux supply is in progress, FIG. 8 is an enlarged cross-sectional view of the main part of the extrusion molding machine, and FIG. 9 is a view of the flux injection nozzle holder part. Front view, FIG. 10 is an explanatory view of a flux injection nozzle body, a) is a front view, (b) is a side view.

  An example of the implementation of the lead-free flux-containing solder busbar manufacturing method of the present invention will be described below based on the flowchart of FIG.

  In the lead-free flux-filled solder bus manufacturing method having the flux supply device FS and the extrusion molding machine EX, the flux material is put into the flux tank 1 with the lid 1a of the flux tank 1 removed and the flux press-fitting plug lifted. Then, the lid 1a is closed (step S1). A predetermined sequence control program suitable for the type of flux is started (SW, ON) (step S2), and the flux fx is heated by the heater 1c provided on the outer periphery of the tank for imparting fluidity to the flux fx. (Step S3), does the heater 1c reach a predetermined temperature? Is confirmed (step S4). The appropriate temperature varies depending on the type of flux fx, and is usually set to any one within the range of 70 to 160 ° C. If the temperature has reached an appropriate temperature, the exhaust means Ej starts to be driven when the time switch is turned on, and at the same time, the deaeration on-off valve 2 is opened to maintain the deaeration state immediately before the bumping occurrence limit, and the molten flux in the flux tank 1 is maintained. The degassing process of the air in the liquid top surface gap AS and the melt flux of fxm is started (step S5), and after the degassing for a predetermined time, the exhaust means Ej is stopped by the time switch OFF (step S6), and the degassing opening / closing The valve 2 is opened and operated via the level detection means 6 for detecting the liquid level of the melt flux fxm together with the plunger 4 for vertical movement and the plug position detection means 5 cooperating with the connecting members 4a and 4b connected thereto. The flux press-fitting plug 3 is lowered (step S7), and the sensor portion 6a provided below the tip sensor portion 6a of the level detecting means 6 is opened and sealed. The sensor opening / closing valve 7b opens when the float 7a of the sensor opening / closing valve 7 with a float that comes into contact with the liquid surface of the molten flux fxm, and then heats when the sensor 6a is immersed in the liquid of the molten flux fxm. An electromotive force is generated (step S8), and the deaeration operation is stopped by closing the deaeration on-off valve 2 via an electromagnetic switch (not shown) by the action of the thermoelectromotive force (step S9), and then the flux The flux supply on-off valve (cock) CS at the bottom of the tank 1 is opened (step S10), and simultaneously with the start of the extrusion molding machine EX, the flux is press-fitted in conjunction with the level detection means 6 and the plug position detection means 5. The melt flux fxm deaerated using the plug 3 is pushed down at a predetermined speed, and the flow path 17 and the flux injection nozzle 14 connected downward are connected. Then, the forced injection operation is started in the opening portion opened in the center portion during the extrusion of the solder bus bar (step S11), and the plug position detection is performed in order to obtain the consumption amount of the flux fx in the flux tank 1 within a predetermined time. The position level of the means 5 is detected (step S12), and at the same time, the manufacturing length of the solder bus 18 is measured in order to obtain the consumption amount of the flux fx injected into the solder bus within a predetermined time (step S13). The balance of flux consumption is calculated from the output value A of the change amount of the plug position level and the output value B of the manufacturing length of the solder bus 18, and A ≧ B is established and falls within a predetermined range. It is confirmed that the flux fx is supplied without interruption (step S14). Before the molten flux fxm in the flux tank 1 is consumed by a predetermined amount and the remaining amount in the tank 1 is exhausted, that is, when the lowermost surface 3d of the plug 3 approaches the bottom plate portion 1g of the tank 1, it is provided on the plunger for vertically moving the plug. The limit switch LS is actuated to stop the lowering operation of the plug 3 and switch to the next flux supply device FS ready and waiting (step S15). When manufacturing continuously, it returns to step 4 and a process is repeated.

  Since the flux used for lead-free solder has high viscoelasticity, it takes time to sufficiently deaerate the air in the flux by suppressing the bumping phenomenon.

  For this reason, a spare tank of the same specification was also installed, and degassing was performed using the flux injection time of the tank in operation. The degassing conditions were sufficient for degassing at a vacuum level where the degassing passage was not blocked by entrainment of droplets below the superheat temperature of each material. The deaeration passage can be heated so that the vapor of the flux is not condensed and solidified.

  (A) Optical method, (b) Ultrasonic method, (c) Image processing method, (d) Laser radar method, (e) Microwave method, (f) Radioactivity , X-ray, γ-ray system, (g) infrared system, etc. have been proposed, but none were satisfactory in various conditions such as detection atmosphere, safety, responsiveness, accuracy, and cost.

  As the forced injection method, (a) pressurized gas and (b) pressurized plug were considered, but the pressurized gas method (a) was not usable after degassing because of gas re-permeation.

  The flux press-fit plug has an O-ring provided around the lowermost periphery of the bottom of the plug, and can push down the molten flux while sliding on the inner wall of the flux tank in an air tight manner.

  The plug position detection means uses a variable resistor to detect the change of the resistance value linked with the liquid surface position of the molten flux and to detect the bus manufacturing speed with a speed meter and calculate the correlation between the two data. It was calculated by means and it was confirmed that there was no flux break.

  FIG. 2 is a block diagram showing a main configuration, (a) is a block diagram showing a series of systems composed of main elements, and (b) is a block diagram showing a system configuration.

  In FIG. 2A, the flux supply device FS is composed of a plurality of A, B, C..., And its main constituent elements also serve as (1) the flux tank 1 and the material input port incidental thereto. Flux heating heater 1c provided around lid 1a and tank outer periphery, (2) Flux press-fitting plug 3, plug support rod 3a attached thereto, heater 3c provided around this, and plug 3 main body. Plunger portion 4 for vertical movement, plug position detecting means 5, (3) flux level detecting means 6 comprising a thermocouple, double pipe (double cylinder) 6b with an air jacket attached thereto ( 4) Deaeration mechanism EK, valve body 2a incidental thereto, deaeration on-off valve 2 comprising valve seat 2b, valve body support rod 2c, outer periphery of valve body 2a support rod 2c and inner periphery of plug support rod 3a A degassing passage 2d on the side, And heater 3c provided on the inner peripheral side of the plug support rod 3a for heating the deaeration passage 2d, (5) sensor open / close valve 7b with float 7a (double pipe with air jacket (double pipe (Cylinder) 6b has a function of opening or sealing the sensor portion 6a of the thermocouple 6 attached to the tip of the thermocouple 6. This sensor 6a is slightly behind the tip of the double tube (double cylinder) 6b. It is provided by being retracted into

  A calculation means OP is provided, and each output value from the measuring device Me for measuring the manufacturing length of the flux-cored solder bus of the extrusion molding machine EX is stored in the RAM, and the balance (consumption) of the flux is calculated by the CPU. Calculate. In addition, an input unit that can be manually input is provided to complement sequence control.

  An extrusion molding machine EX having a flux injection nozzle 14 and a solder material extrusion mechanism (including ram and die) RK is connected and connected to a wire drawing machine WD that can further reduce the product.

  FIG. 2B is a block diagram showing a system configuration.

  2B, the flux supply device FS is composed of a plurality of A, B, C... And is a system that can supply a sufficiently degassed molten flux. CS is a flux supply / switching cock, and 17 is a flux flow path. Since the other symbols are as described above, description thereof is omitted.

FIG. 3 is a partially broken side view showing the configuration of the main part of the flux supply device, which includes a flux tank 1, a flux press-fitting plug 3, a flux level detection means 6, a deaeration mechanism EK, and a plug position detection means 5. A lead-free flux-containing solder busbar manufacturing device including a flux supply device FS, wherein the flux tank 1 has a lid portion 1a detachably fixed, and imparts fluidity to the flux f on the outer peripheral surface of the tank. A heater 1c is provided around, and the flux fx can be stored and supplied. The flux press-fit plug 3 is suspended from the plug support rod 3a and interlocked with an arm portion 4b provided continuously to the plug support rod 3a. The flux fx in the flux tank 1 is sent and supplied via the plunger part 4 that can be moved up and down, and the flow path 17 and the flat connected to the lower part are connected. The flux fx can be continuously injected along the longitudinal direction into the center of the solder bus bar during extrusion molding via the gas injection nozzle 14, and the valve element 2a of the degassing on-off valve 2 is supported by the valve element. 2c is suspended and fixed, a double cylinder 6b with a cooling function is inserted into the valve body 2a of the deaeration on-off valve 2, and a sensor on-off valve 7b with a float portion 7a is inserted at the tip of the double cylinder 6b. When the float portion 7a of the sensor on-off valve 7b contacts the flux level, the sensor on-off valve 7b is opened by the action of the float portion 7a. Level detecting means 6 for detecting the flux level,
A heating means 3c provided around the inner peripheral surface of the plug support rod 3a; an annular gap portion for forming a degassing passage 2d on the inner surface side of the plug support rod 3a and inside the heating means 3c; A plug body is suspended from and fixed to a lower end of a plug support rod 3a that moves up and down via a sliding ring 1e that is inserted and fitted into the lid portion 1a with a passage 2d as a boundary. A degassing mechanism EK comprising a seat 2b and a degassing on-off valve body 2a that engages with the annular valve seat 2b and is freely detachable
The plug position detecting means 5 moves up and down in conjunction with the plug main body 3 and the plug support rod 3a, and is injected into the solder bus at the same time and the consumption amount of the flux fx in the flux tank 1 at the same time. A lead-free flux-containing solder bus manufacturing apparatus comprising: a calculation means for determining whether a comparison calculation result with a consumption amount of the flux fx within a predetermined time is within a predetermined range.

  As shown in the figure, the valve body 2a has a frustoconical shape, and moves upward to engage and closely contact the annular valve seat 2b fitted on the top of the plug 3. The passage can be blocked.

  With respect to the other symbols, 3b is an O-ring fitted to the lowermost end portion of the outermost periphery of the plug 3, and when the flux fx in the tank 1 is pressed down and supplied, the tank 1 slides down on the inner peripheral surface in an air tight manner. It is as composition to do.

  Reference numeral 2e denotes a connecting portion for connecting to the deaeration passage 2d and the exhaust means outside the system, and 2f denotes a vertical cylinder for moving the valve body 2a up and down via the valve body support rod 2c.

  If is a disk-shaped heater for keeping the lid 1a warm.

  5a is a connecting rod of the plug position detecting means 5 comprising a variable resistor, and is connected to the connecting rod 4a of the vertically moving plunger 4 via the connecting arm 5b, and moves up and down in conjunction with the vertical movement of the plug 3. Thus, the plug position is detected by the resistance value from the variable resistor. Thereafter, the plug 3 detects the position of the molten flux fxm during press-fitting into the opening 19 in the solder bus bar in the same manner.

  The manufacturing speed of the solder bus is detected by a speedometer that is in contact with the traveling bus (for example, a tachometer). Both the output values that are the balance of the flux amount calculated from the momentary plug position detection output value and the bus velocity output value are calculated by the control processing unit of the control system. ) You can check if it is cut. Correlation between the fluctuation amount of the flux tank level and the fluctuation amount of the solder bus manufacturing speed at the time of switching the billet that is the solder bus is maintained, and a reliable result is obtained, so cut in anticipation of flux (grease) running out You no longer need to.

  F is a frame for the apparatus, and a support column PS is provided upright via a vertical position adjustment positioning handle Hn, and includes an upper support arm SU above the support column PS and a lower support arm SL below, and a flux tank. 1 and the flux supply device FS are supported.

  1b is a trunk part of the flux tank 1, and 1d is an outer cylinder part. Arrows i indicate that they are linked simultaneously.

  7c is a swing shaft (support shaft) for rotating the sensor on-off valve with a float.

  6c is a fixing member for fixing the thermocouple 6 to the degassing on-off valve body 2a inserted through the double cylinder 6b having an air cooling jacket.

  1 h is a drain removal plug in the flux tank 1.

  Further, the embodiment will be described in detail. The deaeration condition is a temperature at which sufficient fluidity can be obtained for forced injection by the plug into a continuous hole portion opened at the center of the solder bus bar (because flux is lost at high temperatures). (Low temperature is desirable) (The temperature should be as low as possible). The degree of vacuum was adjusted so that the melted lead-free solder flux would not cause entrainment of bumps and close the deaeration passage. . A function of increasing the degree of vacuum with time so as to shorten the deaeration time may be added. The deaeration passage was provided with a heating mechanism so that steam generated when the flux was deaerated did not condense and solidify on the inner wall of the line to block the line.

  Degassing may be performed by a single mechanism, but it is desirable to transfer the high-viscoelastic melt flux to the injection mechanism after degassing because air may be mixed in and the amount of work will increase greatly. Absent. Therefore, a plurality of spare tanks of the above-mentioned flux supply tank of the same specification were placed side by side, and deaeration was performed using the usage time of the tank during injection.

  After deaeration, it is necessary to check the liquid level of the molten flux. As a liquid level detection method, (a) an optical system, (b) an ultrasonic system, and (c) image processing are known techniques. (D) Laser radar method, (e) Microwave method, (f) Radioactivity, X-ray, γ-ray method, (g) Infrared method, etc. have been proposed, but safety, responsiveness, accuracy There was nothing that could be satisfied from the cost. As a result of earnest research, the present applicant made a study based on the thermocouple method. Although the thermocouple sensor part is immersed in the molten flux liquid surface to generate thermoelectric power, the liquid surface position is detected, but the response and accuracy are not satisfied.

  As a result of intensive studies, (1) the sensor portion of the thermocouple having a large thermoelectric power was made as small as possible in order to increase the thermal conductivity. (2) Until the thermocouple sensor part is immersed in the melt flux liquid, including during degassing, until it is about to be immersed in the flux liquid surface so as not to be affected by the temperature of the gas above the flux liquid surface in the flux tank. The gas in the atmosphere above the flux surface was simultaneously heated by a heater provided on the outer periphery of the tank for the purpose of keeping the molten flux warm.

  Due to the above improvement, the liquid level detection of the melt flux fxm can be satisfied for the first time in terms of responsiveness, accuracy and cost. The material of the flux tank 1 and the like including the thermocouple 6 is one that can withstand the corrosiveness of the flux fx (SUS304 described later).

  The plug 3 placed at a position where the droplets accompanying degassing do not reach the plug 3 is lowered, and the sensor portion 6a of the thermocouple 6 is immersed in the molten flux fxm. Sensor part shielding door (sensor opening / closing valve) that opens with the buoyancy of a float (float part 7a) provided at the tip of a pipe (double cylinder 6b) through which fluid (air) for blocking heat from the outside can pass 7b) opens. Cylinder (2f) that operates the deaeration on-off valve 2 opened during deaeration by the thermoelectromotive force generated at the temperature of the melt flux fxm by the sensor portion 6a of the thermocouple 6 immersed in the liquid of the melt flux fxm When an electromagnetic open / close switch (not shown) is turned on and the deaeration on / off valve 2 is closed, no gas remains on the flux liquid surface and the plug bottom surface, and the molten flux enters the deaeration passage 2d. Without degassing can be maintained.

  FIG. 4 is a detailed cross-sectional view of the main part, showing the operation of the peripheral part of the plug 3 and the sensor on / off valve 7 with a float part, the float part 7a and the sensor on / off valve 7b. It is a representation.

  5A and 5B are main part cross-sectional views showing the operation, wherein FIG. 5A is a main part cross-sectional view showing an initial state, and FIG. 5B is a main part cross-sectional view showing a state at the start of deaeration.

  In FIG. 5A, the position of the plug 3 is a state separated by a desired distance HS above the liquid surface of the molten flux fxm in the tank 1.

  FIG. 5 (b) shows that the deaeration exhaust means Ej starts driving when the timer switch is ON, and at the same time, the valve body 2a of the deaeration on-off valve 2 is lowered and separated from the valve seat 2b to be engaged. The passage 2d is opened and the deaeration operation is started, and the arrow B represents the situation where the upper gap AS of the flux fx and the air in the liquid of the molten flux fxm are deaerated (exhaust). .

  6 (a) and 6 (b) are main part cross-sectional views showing the state of the intermediate step after the start of operation, and shows the state before the deaeration on-off valve 7 in FIG. (B) shows that the plug 3 starts to descend while continuing the deaerated state, the lowermost end portion 3d of the plug 3 comes into contact with the liquid surface of the molten flux fxm, and subsequently the double cylinder as the plug 3 descends. The float 7a of the sensor opening / closing valve 7 with a float provided at the tip of 6b abuts against the liquid surface of the melt flux fxm, and the float is lifted upward with the pivot shaft 7c as a fulcrum and floats. The sensor opening / closing valve 7b on the opposite side across 7c is in a vertical state, the sensor unit 6a is opened, the sensor unit 6a is immersed in the liquid of the melt flux fxm, and a thermoelectromotive force is generated at the same time. Deaeration via electromagnetic switch and valve body upper / lower cylinder 2f It is a state in which the opening-closing valve body 2a is closed degassing line containing a mating contact to degassing passage annular valve seat 2b engaging rises.

  FIG. 7 is a cross-sectional view of the main part showing a state in which the flux supply is in progress. Following the state of FIG. 6, the plug 3 descends to depress the molten flux fxm and supply the molten flux fxm to the extruder. It shows the state. An arrow C represents a state in which the plug 3 and the related part are lowered in conjunction with each other.

  FIG. 8 is an enlarged cross-sectional view of the main part of the extrusion molding machine. 10 is a press platen serving as a platen, 11 is a die, 12 is a container, 13 is a stem connected to a ram serving as a piston, and 14 is a nozzle (grease nozzle). ), 15 is a nozzle holder, 16 is a solder material, 17 is a flack flow path, 17a is an upper flow path (attachment portion), 17b is a lower flow path, 18 is a flux-cored solder bus product, and 19 is a solder bus bar. It is a hole and a part into which flux is injected.

  FIG. 9 is a front view of the flux injection nozzle holder, in which 15 is a nozzle holder, 15a is an arm, and 15b is a boss, so that the nozzle body can be mounted.

  FIG. 10 is an explanatory view of a flux injection nozzle body, in which (a) is a front view and (b) is a side view. 14a is a nozzle tip part, 14b is a nozzle mounting part having a male thread part to be screwed to the boss 15b of the nozzle holder 15, and 14c is a tool chamfering part provided on a conical surface of the nozzle body.

  Hereinafter, numerical values will be shown to describe embodiments in detail.

  Using a Sn-3Ag-0.5Cu lead-free solder and the aforementioned lead-free solder flux, a flux-cored solder bus with an outer diameter of 10 to 13 mmφ and a flux injection hole diameter of 0.42 to 0.45 mmφ is 5 to 15 m / min. Manufactured at a production rate of The shape of the solder billet was set to 80 mmφ × 450 mmL in view of cooling and workability during casting.

  The flux tank size was 8 to 13 billets / cycle, the actual volume was 4 l (4 liters), the maximum volume was 5 l (5 liters) to avoid entrainment, and the inner diameter was 120 mmφ × height 450 mmH. Flux tank 1, plug 3, operating support rod (shaft) 3a thereof, degassing on-off valve 2, valve body support rod (operating shaft) 2c, and other parts in contact with flux fx are corrosive to the activator containing flux. Sustainable SUS304 was used.

  The outer surface of the plug support shaft (shaft) 3a also serves as a heat insulating layer so that the vapor generated at the time of deaeration does not condense and solidify on the inner wall of the deaeration passage and block the deaeration line including the deaeration passage 2d. A heater 3c with a cover was provided to maintain a temperature above the vapor freezing point (150 ° C. or higher). A thermocouple sensor for detecting the flux liquid level with a thermoelectromotive force generated by the liquid temperature is provided in a valve opening / closing valve body support shaft (shaft) 2c having a deaeration on-off valve 2 at the lower end. A double pipe (double cylinder) 6b made of a heat-insulating material through which a cooling fluid that shields it from being affected by the temperature of the gas in the tank 1 before being immersed in the inside, and a flux A sensor on-off valve 7b that opens at a float (float portion) 7a that enters and floats on the liquid is provided below the sensor portion 6a. A thermocouple is provided in the double pipe (cylindrical body), and the sensor portion 6a and other portions of the thermocouple 6 are sealed in the pipe (cylindrical body) by a blocking member 6d (see FIGS. 3 and 4). . As the sensor portion 6a of the thermocouple 6, in order to improve heat conduction, the normally used wire diameter of 5 mmφ is reduced to 1 mmφ. As the combination of metal wires, chromel-constantan having the highest thermoelectromotive force characteristic among JIS standards is adopted, but platinum-platinum rhodium may be used because of corrosion resistance.

  The sensor unit 6a is attached to the tip of the double cylinder 6b in consideration of the timing of immersion in the flux liquid, generation of electromotive force, plug operation mechanism switching by electromotive force, plug operation and degassing on-off valve operation. The position is set slightly retracted from the position. Since the plug operation mechanism is required to have the plug bottom surface 1g coincide with the flux liquid surface after switching, the liquid operation is more desirable than the gas with volume fluctuation. Sealing of the sliding portion between the inner wall of the tank 1 and the plug 3 was performed with a fluorine resin O-ring 3b inserted in a groove provided in the outer periphery of the plug.

  After closing the flux supply cock CS to the extrusion machine EX provided below the tank 1 where the material flux is set to a temperature at which necessary fluidity can be obtained (depending on the type of flux, but the appropriate temperature is 70 to 160 ° C.) The material was injected, the inlet was closed, and the deaeration operation was performed.

  A vacuum ejector (vacuum pump) is used for deaeration, and at the start of deaeration, start with a low vacuum so that the deaeration passage is not closed due to entrainment of bumps, and flux consumption of 40 liters (40 liters) per cycle Time (bus diameter 13mmφ, hole diameter 4.5mmφ, about 17 minutes for 15m / min, bus diameter 10mmφ, hole diameter 4.2mmφ, about 58 minutes for 5m / min) At the final stage, the degree of vacuum is max-50Kpa Deaerated. In the degassing line outside the flux tank 1, the volatile components contained in the exhaust gas being degassed are cooled and condensed using a cooling device having a regenerating function so as not to enter the vacuum ejector.

  After deaeration was completed, the bottom end 3d of the plug was brought into contact with the flux surface by the electromotive force of the thermocouple as described above, and at the same time, the deaeration valve was closed.

In order to improve the responsiveness and accuracy of the thermocouple method as the liquid level detection method immediately after deaeration, in order to shield the thermocouple from a temperature other than the melt flux temperature, the sensor part is surrounded by a thermal barrier layer until it is immersed from the liquid level. The fluid that passes through the double pipe (double cylinder) 6b of the heat shielding layer that forms the annular passage in the cross section was pressurized air. A door (sensor opening / closing valve 7b) that generates buoyancy in the flux fx solution and opens with the buoyancy is provided so that the sensor unit 6a can enter the flux fx solution during immersion. Chromel-Constantan with the largest thermoelectromotive force, a thermocouple 6 with a thin diameter of 1 mmφ having a good thermal conductivity and good response, is selected, and the deaeration passage 2d is selected from the delay in the closing timing of the deaeration on-off valve 2. Therefore, the melt flux fxm does not enter and the passage is not blocked, and gas (air) remains between the bottom end 3d of the plug and the melt flux fxm liquid level, and the subsequent liquid level detection becomes inaccurate. lost. The position of the flux fx liquid level immediately after deaeration can be detected by the plug position detecting means 5 constituted by the sliding resistance type position sensor interlocked with the plug bottom end 3d in contact with the flux fx liquid level as described above. The flux fx injection amount was calculated by the equation (π / 4) · D ² · H, where the tank inner diameter D = 120 mmφ and the flux level change amount was H. The flux level in the tank 1 was displayed using OMRON K3MA--J-A2.

  The flux consumption is calculated based on the bus bar manufacturing speed Xm / min × hole diameter (4.2 mmφ, 4.5 mmφ) × (4.2 mmφ, 4.5 mmφ) × π / 4. Meter K3NX-VD1A-L2 was used.

  From the comparison of the integrated values of both data and the comparison of unit time values, it was possible to confirm the presence or absence of flux breakage. For the above calculation, a sequencer CTIM-CPU 12 manufactured by OMRON was used.

  After degassing, the extrusion of lead-free solder buses started. When a Sn-37Pb lead solder was manufactured at 5 m / min, the die with a cooling mechanism had a die temperature of 70 ° C. In some cases, the die temperature rose to 100-110 ° C. However, when the obtained bus bar was cut in the flow direction and the state of filling of the injected flux fx was confirmed, a lead-free flux-containing solder bus bar with no flux breakage was efficiently manufactured in the manufacturing method according to the present invention.

  The “solder bus bar” in this embodiment is a linear solder obtained by cold extrusion molding a solder billet that has been cast and cut and shaped to a predetermined dimension before the wire drawing process to obtain a linear solder as a final product. is there.

The flowchart which shows an example of the solder bus bar manufacturing method containing lead-free flux based on this invention A block diagram showing a main part configuration, (a) a block diagram showing a series of systems composed of main elements, and (b) a block diagram showing a system configuration. Partially broken side view showing the main configuration of the flux supply device Detailed sectional view of main parts Main part sectional view showing the operation, (a) Main part sectional view showing the initial state, (b) Main part sectional view showing the state at the start of deaeration (A), (b) Main part sectional drawing which shows the state of the intermediate | middle step after operation | movement start Cross section of the main part showing the state of flux supply in progress Expanded cross-sectional view of the main part of an extrusion molding machine Front view of flux injection nozzle holder Explanatory drawing of the flux injection nozzle body, (a) front view, (b) side view

Explanation of symbols

1 Flux tank 2 Degassing on-off valve 3 Plug (flux press-fit plug)
4 Plunger for vertical movement 5 Plug position detecting means 6 Level detecting means 6a Sensor part 7 Sensor open / close valve with float part 7a Float part 7b Sensor open / close valve 11 Die 12 Container 13 Stem 14 Nozzle (flux injection nozzle)
15 Nozzle holder 16 Solder material 17 Flow path 18 Solder busbar (Flux containing solder busbar)
19 Opening part EK Deaeration mechanism FS Flux supply device Ej Exhaust means EX Extrusion machine fx Flux fxm Melt flux CS Flux supply on / off valve (cock)

Claims (6)

  In a lead-free flux-containing solder bus manufacturing method having a flux supply device and an extrusion molding machine, a heating step of heating the flux with a heater provided on the outer periphery of the tank for imparting fluidity to the flux in the flux tank, and a timer When the switch is turned on, the degassing on-off valve is opened to operate the exhaust means, and while maintaining the degassing state immediately before the bumping limit, the air in the molten flux and the air in the molten flux are degassed. For the vertical movement together with the level detecting means for detecting the molten flux liquid level with the deaeration on / off valve opened, Flux pressure operated via a plunger and a plug position detecting means cooperating with a connecting member connected to the plunger. When the float portion of the sensor on-off valve with a float portion that can lower and lower the plug for opening and closing the sensor portion provided below the tip sensor portion of the level detection means contacts the liquid level of the molten flux When the sensor opening / closing valve is opened and then the sensor section is immersed in the molten flux liquid, a thermoelectromotive force is generated, and the action of the thermoelectromotive force closes the degassing on / off valve via the electromagnetic switch. Deaeration stop process for stopping the gas operation, and the flux depressurized at a predetermined speed by using the flux press-fitting plug that moves up and down in conjunction with the level detection means and the plug position detection means, and the flow connected downward A flux injection process for forcibly injecting into a hole opened in the center of the solder bus bar through the passage and the flux injection nozzle, and a flux in the flux tank. And a calculation step of determining whether a comparison calculation result of the consumption of the flux within a predetermined time and the consumption of the flux injected into the solder bus at the same time within a predetermined time is within a predetermined range. A method for producing a lead-free flux-filled solder bus characterized by the above.   2. The deaeration process according to claim 1, wherein in the deaeration step, the deaeration path is heated in order to prevent the deaeration path from being blocked due to condensation / fixation of vapor contained in the air being deaerated. Of lead-free flux-containing solder busbars.   A plurality of spare devices having the same specifications as those of the flux supply device according to claim 1 are provided, and the temperature range for maintaining the required fluidity and the degassing passage are blocked by entrainment of droplets during operation of the flux supply device in use. Lead-free flux-filled solder bus manufacturing, characterized in that the deaeration state just before the limit of bumping occurrence is maintained at a vacuum level that does not occur, and it can be deaerated to an allowable volatile content rate Method. A lead-free flux-containing solder busbar manufacturing device including a flux supply device composed of a flux tank, a flux press-fit plug, a flux level detection means, a deaeration mechanism, and a plug position detection means,
The flux tank has a lid part that is detachably fixed, and a heater for imparting fluidity to the flux is provided around the outer peripheral surface of the tank to store and supply the flux.
The flux press-fitting plug is suspended from a plug support rod, and sends and supplies the flux in the flux tank via a plunger portion that can move up and down in conjunction with an arm portion that is connected to the plug support rod. The flux can be continuously injected along the longitudinal direction into the central part of the solder bus bar during extrusion molding via a flow path and a flux injection nozzle connected downward, and a valve body of a deaeration on-off valve can be provided. Suspended and fixed at the lower end of the valve body support rod, a double cylinder with cooling function is inserted vertically into the valve body of the deaeration on-off valve, and a sensor with a float at the end of the double cylinder is opened and closed. Provided with a valve, facing the tip through the sensor on-off valve, and when the float part of the sensor on-off valve contacts the flux liquid level, the sensor on-off valve opens by the action of the float part to The level to detect And a le detecting means,
The heating means provided around the inner peripheral surface of the plug support rod, the annular gap forming the degassing passage on the inner surface side of the plug support rod and inside the heating means, and the degassing passage as a boundary. A plug body is suspended and fixed via an annular valve seat at the lower end of a plug support rod that moves up and down via a sliding ring inserted and fitted in the lid portion, and is engaged with the annular valve seat and the annular valve seat. It has a deaeration mechanism consisting of an open / close valve body for degassing that can be freely fitted and removed.
The plug position detecting means moves up and down in conjunction with the plug body and the plug support rod, and consumes the flux in the flux tank for a predetermined time and within a predetermined time for the flux injected into the solder bus at the same timing. An apparatus for manufacturing a lead-free flux-containing solder bus, comprising: a calculation means for determining whether a result of a comparison operation with the consumption amount of the lead is within a predetermined range.   The level detecting means is composed of a thermocouple having corrosion resistance, and the thermocouple is accommodated in a double cylinder having an air jacket, and the double cylinder is inserted into and fixed to a deaeration on-off valve body on the outside thereof. A tubular valve body supporting rod that can be moved up and down together with the deaeration on-off valve body by suspending and fixing the deaeration on-off valve body, and is surrounded by a deaeration passage. 4. The lead-free flux-containing solder bus bar manufacturing apparatus according to 4.   The deaeration mechanism has a plurality of exhaust means shared by the flux supply devices, and the flux that is heated to a predetermined temperature and has fluidity maintains the deaeration state immediately before the bumping occurrence limit, while the flux liquid in the flux tank is maintained. A degassing on / off valve for degassing the air in the upper surface gap and flux, the degassing on / off valve senses the thermoelectromotive force generated by the thermocouple and moves upward to degas The lead-free flux-containing solder bus bar manufacturing apparatus according to claim 4, wherein the passage is closed.

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