JP2015227859A - Creation method of solder test piece - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a creation method of a solder test piece that allows for appropriate evaluation of a solder material by preventing an oxide film from formed on a surface of the test piece.SOLUTION: A creation method includes a flux application process of applying a flux on a cavity 11 of a split mold 9, a heating process of filling the cavity 11 with the solder material 25 after the flux application and heating the cavity to a solder melting temperature, a solder solidification process of cooling a solder at a predetermined cooling speed after the heated melting and forming a solder test piece 14 with a rust prevention coating 26 deriving from the flux attached to the surface, and a test piece take-out process of taking out the solder test piece 14 from the split mold 9 after the solidification. The processes are performed in this sequence.

Description

  The present invention relates to a method for producing a solder test piece in which a solder test piece is produced by sequentially performing melting and cooling processes on a solder material filled in a split mold cavity.

  A method for producing such a solder test piece is known from Patent Document 1.

JP 2008-241656 A

  However, in the one disclosed in the above-mentioned Patent Document 1, an oxide skin is formed on the surface of the solder immediately after the solder is melted in the split mold and discolors, and the oxide film greatly affects the physical properties of the solder. Appropriate evaluation of becomes difficult.

  It is an object of the present invention to provide a method for producing a solder test piece that avoids the formation of an oxide film on the surface of the solder test piece and enables proper evaluation of the solder material.

  In order to achieve the above object, the present invention provides a method for producing a solder test piece in which a solder test piece is produced by sequentially performing melting and cooling processes on a solder material filled in a cavity of a split mold. A flux application step of applying a flux to the cavity of the split mold, a heating step of filling the cavity with the flux applied and heating to a solder melting temperature, and after heating and melting A solder solidification step of cooling the solder at a predetermined cooling rate to form a solder test piece having a rust-preventing film derived from the flux adhered to the surface, and a solder test for removing the solder test piece from the split mold after solidification The first feature is to execute the piece extraction step in this order.

  Moreover, in addition to the structure of the 1st characteristic, this invention evaluates the physical characteristic of the said solder test piece in addition to the said flux application | coating process, the said heating process, the said solder solidification process, and the said solder test piece taking-out process. The second feature is that a cleaning step of peeling and cleaning the rust preventive film from the solder test piece is performed.

  In addition to the configuration of the first or second feature, the third feature of the present invention is that the flux is a resin flux for solder.

  Furthermore, in addition to the configuration of the third feature, the present invention has a fourth feature that the solder is a lead-free solder.

  According to the first aspect of the present invention, the flux is applied to the cavity before filling the cavity of the split mold with the solder material. It is possible to form a solder test piece having a surface adhered to the surface, and an oxide film is formed on the surface of the solder test piece without discoloration, and appropriate evaluation for the solder test is possible.

  Further, according to the second feature of the present invention, when the physical characteristics of the solder test piece are evaluated, the rust preventive film is peeled off from the solder test piece to suppress the oxidation of the solder at a high temperature state. However, the solder characteristic test using the solder test piece can be performed without being affected by the antirust film derived from the flux.

  According to the third feature of the present invention, by selecting a resin flux for solder as a flux, it is possible to suppress solder oxidation and to make a solder test piece suitable.

  Furthermore, according to the fourth feature of the present invention, it is suitable for preparing a test piece of lead-free solder. In other words, lead-free solder is Sn-based and has a high melting point compared to lead-containing solder, and the oxide generation rate on the solder surface is increased, but it is derived from a flux that suppresses the oxidation of solder at high temperatures. Since the solder test piece is prepared in a state where the rust preventive film is deposited on the surface, it is possible to more effectively prevent oxide formation.

It is a top view of the preparation apparatus of a solder test piece. It is a side view of a solder test piece. It is a figure which shows the preparation process of a solder test piece sequentially.

  The embodiment of the present invention will be described with reference to FIG. 1 to FIG. 3. First, in FIG. 1, a solder test piece preparation device includes a fixed holder 5 that is fixedly arranged, and a fixed holder 5 in the Y direction. A movable holder 6 that is disposed oppositely, a fixed mold 7 that is fixed to the fixed holder 5, and a movable mold 8 that is fixed to the movable holder 6 so as to form a split mold 9 together with the fixed mold 7. . Around the fixed mold 7, the fixed holder 5 is provided with a plurality of guide columns 10 extending in the Y direction. The guide pillars 10 are inserted into the movable holder 6, and the movable holder 6 is movable along the Y direction so as to approach and separate from the fixed holder 5.

  Further, temperature regulators 30, 31 adjacent to the fixed mold 7 and the movable mold 8 in the split mold 9 are disposed in the fixed holder 5 and the movable holder 6. These temperature regulators 30, 31 have a heat transfer heater and a refrigerant passage for circulating the refrigerant, and heating by the heat transfer heater and cooling by circulation of the refrigerant are controlled by a control device (not shown), Thereby, the fixed mold 7 and the movable mold 8 can be heated to 250 ° C., for example, and can be cooled at a desired cooling rate after the heat treatment.

  On the surfaces of the fixed mold 7 and the movable mold 8 facing each other, when the movable mold 8 abuts on the fixed mold 7 to form the split mold 9, a recess 12 for forming a cavity 11 is formed. 13 are formed. The cavity 11 has a shape corresponding to the solder test piece 14 shown in FIG. 2, and the solder test piece 14 has a diameter larger than that of the breakage test part 15 at both ends of a rod-like breakage test part 15. A certain bar-shaped knob portion 16 is connected to each other via a taper portion 17 and is formed in a size corresponding to the application of the solder to be evaluated. For example, when the solder through hole of 0.5 mmΦ of the electronic substrate is an evaluation object, the outer diameter of the fracture test portion 15 is set to 0.5 mmΦ.

  Referring again to FIG. 1, the solder test piece preparation apparatus includes a spray device 18 that is removably inserted between the fixed holder 5 and the movable holder 6 that are separated from each other. Reference numeral 18 denotes a drive unit 19 having a constant position along the X direction perpendicular to the Y direction, a support unit 20 disposed at a distance from the drive unit 19 in the X direction, and one end of the drive unit 19. A screw shaft 21 that extends in the X direction so that the portion is supported and whose other end is rotatably supported by the support unit 20, and rotation around the axis of the screw shaft 21 is disabled. And a spray unit 22 to be screwed together.

  The screw shaft 21 is rotationally driven by the drive unit 19, and the spray unit 22 moves in the X direction according to the rotation of the screw shaft 21. The spray unit 22 includes a spray nozzle 23 for spraying a flux toward the fixed mold 7 and a spray nozzle 24 for spraying a flux toward the movable mold 8. The flux can be sprayed on a portion including the concave portions 12 and 13 for forming the cavity 11 on the opposing surface of the movable mold 8.

  The spray device 18 is arranged between the fixed holder 5 and the movable holder 6 when the fixed holder 5 and the movable holder 6 are separated from each other. When the fixed mold 7 and the movable mold 8 are clamped, the fixed mold 7 and the movable holder 6 are moved away from the fixed holder 5 and the movable holder 6 by moving in a direction perpendicular to the paper surface of FIG.

  As the flux, a resin-based flux for solder is used. For example, an RMA type (chlorine <0.14 wt%) or R type flux of the former US Federal Standard QQ-S-571 oxidizes solder. It is preferable because it is difficult.

  In order to prepare the solder test piece 14 using such a solder test piece preparation apparatus, a flux application process, a heating process, a solder solidification process, a solder test piece removal process, and a cleaning process are sequentially executed.

  First, in the flux application step, the flux is applied to the cavity 11 of the split mold 9, and as shown in FIG. 3A, the fixed mold 7 and the movable mold 8 that are separated from each other. The flux is sprayed by the spray device 18 to the portion including the concave portions 12 and 13 for forming the cavity 11 in the facing surface. At this time, in order to prevent the flux from dripping at the unstable start of spraying and at the end of spraying, it is desirable to spray in a range slightly larger than the recesses 12 and 13.

  In the next heating step, the cavity 11 with the flux applied is filled with the solder material 25 and heated to the solder melting temperature. As shown in FIG. After the solder material 25 is inserted between the movable molds 8, the mold is clamped as shown in FIG. 3C to heat the solder material 25 to the solder melting temperature, for example, 250 ° C. while filling the cavity 11.

  As the solder material 25, it is possible to suitably use a solder paste obtained by chopping a lump of solder supplied from a solder manufacturer, or a solder paste obtained by kneading solder powder and flux. The solder is lead-free solder. It is desirable to be.

  In the solder solidification step, the solder after heating and melting is cooled at a predetermined cooling rate to form a solder test piece 14 having a rust preventive film 26 derived from the flux attached to the surface. The solder solder solidification step In the next step of taking out the solder test piece 14, as shown in FIG. 3D, the rust preventive film 26 adheres to the surface of the solder test piece 14.

  Further, in the cleaning process, as shown in FIG. 3 (e), the rust preventive film 26 is peeled and cleaned from the solder test piece 14, and at this time, a vapor of a cleaning agent such as isopropyl alcohol or hydrofluoroether is used. The solder test piece 14 from which the rust preventive film 26 has been peeled off can be obtained by spraying on the surface of the solder test piece 14 and washing and drying.

  The evaluation test of the solder test piece 14 obtained through the cleaning step is performed by a test apparatus 27 that holds the knob 16.

  By the way, depending on the test conditions, the peeling of the rust preventive film from the solder test piece 14 may not always be necessary. In that case, the solder test obtained in the solder test piece take-out step without going through the cleaning step. The evaluation test is performed with the piece 14 as it is.

  Next, the operation of this embodiment will be described. In forming the solder test piece 14, a flux applying step for applying a flux to the cavity 11 of the split mold 9, and the cavity in a state where the flux is applied. 11 is filled with the solder material 25 and heated to the solder melting temperature, and the solder after heating and melting is cooled at a predetermined cooling rate, and the rust preventive film 26 derived from the flux adheres to the surface. Since the solder solidification step for forming the test piece 14 and the solder test piece removal step for removing the solder test piece 14 from the split mold 9 after solidification are executed in this order, the solder solidification step is performed by cooling after heating to the solder melting temperature. It is possible to form the solder test piece 14 with the anticorrosive film 26 derived from the agent attached to the surface, and an oxide film is formed on the surface of the solder test piece 14 and discolors. That there is no, it is possible to appropriate evaluation of the solder material.

  Further, in addition to the flux application step, the heating step, the solder solidification step, and the solder test piece removal step, the rust preventive film 26 is removed from the solder test piece 14 when the physical properties of the solder test piece 14 are evaluated. Since the cleaning process for peeling and cleaning is performed, the solder characteristics using the solder test piece 14 are suppressed without being influenced by the rust preventive film derived from the flux while suppressing the oxidation of the solder in a high temperature state. A test can be performed.

  Further, since the flux is a resin flux for solder, it is possible to suppress the oxidation of the solder and to make it suitable for making the solder test piece 14.

  And since the said solder is lead-free solder, it becomes suitable for test piece preparation of lead-free solder. In other words, lead-free solder is Sn-based and has a high melting point compared to lead-containing solder, and the oxide generation rate on the solder surface is increased, but it is derived from a flux that suppresses the oxidation of solder at high temperatures. Since the solder test piece 14 is prepared in a state where the rust preventive film is deposited on the surface, it is possible to more effectively prevent oxide formation.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the present invention described in the claims. Is possible.

9 ... Split mold 11 ... Cavity 14 ... Solder specimen 25 ... Solder material 26 ... Rust prevention coating

Claims (4)

  A method for producing a solder test piece in which a solder test piece (14) is produced by sequentially subjecting a solder material (25) filled in a cavity (11) of a split mold (9) to melting and cooling. A flux applying step of applying a flux to the cavity (11) of the split mold (9), and a solder material (25) is filled in the cavity (11) in a state where the flux is applied. A heating step for heating to a melting temperature, and a solder for forming a solder test piece (14) having a rust preventive film (26) derived from the flux adhered to the surface by cooling the solder after heating and melting at a predetermined cooling rate. A method for producing a solder test piece, comprising performing a solidification step and a solder test piece removal step for taking out the solder test piece (14) from the split mold (9) after solidification in this order.   In addition to the flux application step, the heating step, the solder solidification step, and the solder test piece removal step, the rust preventive film (26) is applied to the solder test piece when evaluating physical properties of the solder test piece (14). The method for producing a solder test piece according to claim 1, wherein a cleaning step of peeling and cleaning from the test piece (14) is executed.   The method for producing a solder test piece according to claim 1, wherein the flux is a resin-based flux for solder.   The method for producing a solder test piece according to claim 3, wherein the solder is lead-free solder.

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