JP4611851B2 - Solder rolling method and solder rolling mill - Google Patents

Description

  The present invention relates to a rolling method and a rolling machine suitable for rolling solder, particularly lead-free solder containing Sn as a main component.

  Generally, the solder type includes wire solder, solder paste, and foam solder.

  As the wire-shaped solder, there are a wire-containing solder with a spear and a wire solder without a spear. In manufacturing these wire solders, a billet of solder is extruded into a so-called original wire having a large wire diameter by an extruder, and the original wire is drawn to a desired wire diameter by a wire drawing machine.

  The solder paste is a paste obtained by kneading flux and powdered solder. In the production of the solder powder used for the solder paste, molten solder is dropped from a nozzle, and compressed air is blown onto the molten solder to be dropped to make it fine, and it is cooled and powdered in a large hopper.

  The foam solder has various shapes suitable for the soldered portion such as a disk shape, a rectangle shape, a washer shape, and a frame shape. Since all of the foam solder is thin plate-like, in this production, a long strip-shaped solder material is punched out with a die having a predetermined shape.

  In the production of a strip-shaped solder material used as a raw material for foam solder, a solder billet is first extruded by an extruder to produce a long solder material having a rectangular cross section, and then the solder material is rolled to a predetermined thickness by a rolling mill. The solder material rolled to a predetermined thickness is punched out with a press to form foam solder.

  The rolling mill for rolling solder does not have a large roll for rolling steel material, but is a small rolling mill, that is, a roll having a diameter of 300 mm or less.

  Generally, when a metal material is rolled with a rolling mill, metal powder adheres to the roll surface. This phenomenon is because when the metal material passes between a pair of rotating rolls, the peripheral speed of rotation of the roll and the passing speed of the metal material are different, so that the roll rubs the metal material to generate metal powder. . In the rolling of steel, iron powder is generated, and if it adheres to the surface of the roll, the iron powder attached to the roll damages the rolled iron plate surface. Therefore, conventionally, a steel rolling mill has been provided with a wiper for removing iron powder adhering to the roll (Patent Document 1).

  In a rolling mill for steel, a hard steel material must be rolled, so that a strong pressing force is applied between the steel material and the roll. Therefore, iron powder is pressed with a strong force and firmly adhered to the roll of a rolling mill for steel. In Patent Document 1, in order to remove the iron powder firmly adhered to the roll, the roll is scraped off with a soft material attached to the wiper so as not to be damaged. For this reason, the wiper disclosed in Patent Document 1 has a knife edge in cross section, and the sharpened portion scrapes off the iron powder firmly attached to the roll.

  By the way, also when rolling a solder material, solder powder adheres to the roll of a rolling mill. The solder powder adhering to the roll is rubbed with the roll, and the temperature rises due to frictional heat. Unlike the iron powder that adheres to the steel during rolling, the oxide powder that adheres to the roll tends to peel off from the roll, and thus adheres to the solder material being rolled. The state in which the oxidized powder adheres to the solder material is embedded in the surface of the soft solder. The oxidized powder buried in the surface of the solder material also remains on the surface of the final product, pellets or washers.

When oxidized powder during rolling adheres to the surface of foam solder, there is no reduction in wettability that would be a problem with conventional Pb-Sn solder foam solder, and even if oxidized powder adheres to the surface of foam solder The luster was slightly lost. Therefore, when rolling Pb—Sn solder, it was sufficient for the operator to wipe the oxidized powder adhering to the roll by stopping the roll before and after the rolling operation. However, since lead-free solder itself has poor wettability than Pb-Sn solder, wettability is greatly affected if any oxide powder adheres to the surface of foam solder.
JP-A-5-154517

  Therefore, it is known that if the oxidized powder adhering to the roll is removed, the oxidized powder will not adhere to the solder material being rolled, and it is conceivable that the operator wipes the roll with waste cloth during the work, but the roll rotates. If the wiping operation of the roll is performed while the cloth is in use, the waste is caught between the rolls, which is very dangerous. Therefore, it is only necessary to stop the rolling operation after observing when the oxidized powder has adhered to the roll, and then perform the wiping operation of the roll. However, if the roll is stopped during rolling, traces of the roll remain on the solder material. Or, when the machine is restarted after stopping, an excessive force is applied to the roll with the solder material sandwiched between them, causing the rolling mill to malfunction.

  In order to remove the oxide adhering to the roll, it is conceivable to use a wiper as in Patent Document 1, but the wiper could not completely remove the oxide adhering to the roll. This is because Patent Document 1 is a wiper for a steel rolling machine, and at the time of rolling the steel, the iron powder firmly adhered to the roll with a strong pressing force against the roll and the steel material is scraped off at the tip of the wiper knife edge. It is. However, when the oxide adhering to the roll of the solder rolling mill is to be removed with the wiper of the knife edge, the portion where the wiper is in contact with the roll is linear, and if there is any unevenness on the knife edge of the wiper, the concave portion Is no longer in contact with the roll, and the oxide powder remains without being removed at this portion, and adheres to the solder material being rolled.

  The present inventors, the oxide powder adhered to the roll of the rolling mill for solder is easy to remove by wiping with a soft thing, and if the area of the soft wiping material in contact with the roll is increased, it is easier to remove, The present invention was completed by paying attention to the above.

  The present invention has a concave surface having substantially the same arc as the roll of a rolling mill, and presses the roll surface of the rolling mill with a soft wiping material that is wide in the circumferential direction of the roll, and adheres to the roll surface. A method for rolling solder, comprising rolling a strip-shaped solder material while wiping the oxidized powder of the solder with the wiping material.

  Another embodiment of the present invention is a soft wiping that has a concave surface having substantially the same arc as the roll of the rolling mill at the end of the pressing device capable of adjusting the pressing force, and is wider in the circumferential direction of the roll. A solder rolling machine is characterized in that the material is attached and the wiping material is capable of wiping the oxidized powder of the solder adhering to the roll by pressing the roll surface of the rolling mill.

  According to the present invention, the oxidized powder adhering to the roll of the rolling mill can be completely removed, so that the oxidized powder does not adhere to the strip-shaped solder material being rolled, and as a result, the oxidized powder is also applied to the surface of the foam solder that is the final product. Does not remain. In the present invention, since the wiping material can be pressed against the roll with a constant pressing force, the solder can be rolled while the roll surface is clean. Therefore, the foam solder obtained by the present invention does not have oxidized powder adhered to the surface, and if the workpiece is soldered with the foam solder, the molten solder will spread sufficiently to the soldered part and be reliably soldered. This has an unprecedented excellent effect that the portion can be formed.

  As the wiping material used in the present invention, any material can be used as long as it can clean the oxide powder adhering to the roll without damaging the roll. For example, it is made of a soft material such as felt, rasha, cotton cloth, water-resistant paper, synthetic fiber, resin, rubber or the like. The wiping material needs a certain width, that is, a length in the circumferential direction of the roll. The width of the wiping material suitable for use in the present invention is 10 to 50% of the roll circumference. That is, if the width of the wiping material is smaller than 10% of the roll circumference, the area in contact with the roll becomes small, so that the wiping effect is not sufficient. However, the larger the width is, the more effective the wiping effect is. However, when the pressing device is installed only on one side of the roll, the wiping material is caught in the roll when the width of the wiping material is larger than 25%. Or hinder the passage of solder material. When the width of the wiping material is limited in terms of the rolling work space and the pressing device mounting space and a sufficient area for wiping cannot be secured, a plurality of wiping material pressing devices, for example, both sides of the rolling mill roll ( It may be installed on the rolling material entrance side and exit side) to secure the wiping area. Therefore, the upper limit of the width of the wiping material when the pressing device is installed on both sides of the roll is 50% of the roll circumference.

  The wiping material used in the present invention is attached to the wiping material by wiping with a wiping material instead of scraping off the oxidized powder adhering to the roll. Therefore, if a large amount of oxide adheres to the wiping material, the wiping effect is lost, and at that time, a new wiping material is appropriately replaced.

  The pressing device installed in the rolling mill of the present invention is to press the wiping material attached to the pressed portion against the roll with a constant pressing force. Examples of the pressing portion suitable for use in the present invention include an air cylinder, a compression spring, and a long screw. In the air cylinder, the pressing force can be adjusted in any way depending on the supply state of air to the cylinder. The compression spring always applies a constant pressing force to the roll, but it is difficult to adjust the pressing force, and the long screw can adjust the pressing force each time, but the wiping material is compressed and loses its elasticity. However, it is difficult to follow it. If you combine a compression spring and a long screw, you can take advantage of the advantages of both.

  In the rolling mill of the present invention, the pressing device attached to the rolling mill has a concave surface portion that presses the wiping material so as to follow the position of the roll so as to increase the contact efficiency with the roll.

  The rolling mill of the present invention will be described below with reference to the drawings. 1 is a front sectional view of a solder rolling mill of the present invention, FIG. 2 is a perspective view of a wiping device installed in the rolling mill of FIG. 1, FIG. 3 is a front sectional view of another embodiment, and FIG. It is front sectional drawing of an example.

  First, the embodiment of FIG. 1 will be described. In the rolling mill, a pair of rolls 1 and 2 are installed on the upper and lower parts, and these rolls rotate in opposite directions as shown in the figure. The strip-shaped solder material 3 is inserted between the rolls 1 and 2 and travels as indicated by an arrow A. The space between the pair of rolls 1 and 2 is narrower than the thickness of the solder material 3, and the solder material 3 is rolled when passing between the rolls 1 and 2 to be thin.

  On the sides of the rolls 1 and 2, pressing devices 4 and 4 are installed. The pressing device shown in FIGS. 1 and 2 includes a frame body 5, an air cylinder 6, a guide 7, a holding body 8, and a wiping material 9.

  The frame body 5 has a U-shaped cross section, and an air cylinder 6 is disposed at the bottom surface. A piston 10 is placed in the air cylinder 6 so as to reciprocate as indicated by an arrow B. The air cylinder 6 is provided with intake and discharge ports 11 and 12 communicating with the outside on both sides of the piston 10. These intake / exhaust ports are connected to a compressed air supply source (not shown).

  A sliding rod 13 is fixed to the piston 10, and the other end of the sliding rod is fixed to one side of the guide 7. The guide 7 is movable along the inside of the frame 5 and presses the wiping material attached via a connecting rod, which will be described later, against the roll without being displaced. Two connecting rods 14, 14 are fixed to the other side of the guide 7, and the connecting rods are installed on the holding body 8 so as to freely swing. The swingable movement of the holding body 8 means that the wiping material 9 attached to the holding body 8 is in the state where the upper and lower parts move in and out in the roll direction so that the front surface always contacts the roll 1 uniformly (arrows X and Y). is there.

  The holding body 8 has a concave surface, and a wiping material 9 is attached to the holding body. Even if the holding body 8 does not have the same concave surface as the arcs of the rolls 1 and 2, the wiping material attached to the holding body may be a concave surface having substantially the same arc as the arc of the roll. This is because, since the wiping material 9 is a soft material, when it is attached to the holder and pressed against the roll 1, the wiping material 9 becomes familiar with the roll and becomes a concave surface having substantially the same arc as the peripheral surface of the roll. Thus, if the wiping material becomes a concave surface having substantially the same arc as the arc of the roll, the area where the wiping material is in contact with the roll increases, and the oxidized powder adhering to the roll is efficiently removed. Reference numerals 15 and 15 in FIG. 2 denote attachment pieces fixed to both sides of the frame body 5 for attaching the wiping device to a main body (not shown) of the rolling mill with screws.

  Next, in the rolling mill having the above-described structure, a method for removing the oxidized powder adhered to the roll of the rolling mill will be described.

  Compressed air is sent from a compressed air supply source (not shown) to the intake / exhaust port 12 on the right side of the cylinder 6 in the drawing. Then, the piston 10 moves to the left in FIG. 1, and the holding body 8 also moves to the left through the guide 7 fixed to the piston 10. Since the wiping material 9 is attached to the holding body, the wiping material 9 is pressed against the roll 1 and wipes and removes the oxide powder adhering to the roll 1. At this time, since the wiping material 9 is a concave surface having substantially the same arc as the arc of the roll 1, the wiping material 9 comes into close contact with the roll and efficiently removes the oxidized powder. The pressing force for pressing the wiping material 9 against the roll 1 is adjusted in the supply state of the compressed air sent to the air cylinder 6. The compressed air is supplied by a regulator (not shown) installed between the intake / exhaust port 12 and the compressed air supply source. In this way, rolling is performed while wiping the oxidized powder adhering to the roll surface, and if a large amount of oxidized powder adheres to the wiping material after rolling for a certain period of time or a certain length of the solder material, the air cylinder 6 Compressed air is fed into the other intake / exhaust port 11, the piston 10 is moved to the right in FIG. 1, and the wiping material 9 is removed from the roll 1 and replaced with a new wiping material.

  Next, another embodiment of FIG. 3 will be described. The rolling mill of FIG. 3 uses a long screw as a portion for pressing the wiping material. Here, the same parts as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted. A female screw 16 is screwed on one side of the frame 5, and a long screw 18 having a clamp 17 attached to one end is screwed into the female screw. A guide 7 is attached to the other end of the long screw 18. The attachment state of the long screw 18 and the guide 7 is such that the long screw 18 is rotatable with respect to the guide 7, but is not separated, that is, the guide moves as the long screw moves. The guide 7 and the holding body 8 are connected to each other by a connecting rod 14 such that the guide 7 and the holding body 8 are swingable. A wiping material 9 is attached to the holding body 8. In the rolling mill of FIG. 3, the pressing state of the wiping material on the roll is adjusted by the screwed state of the long screw.

  Next, still another embodiment of FIG. 4 will be described. The rolling mill of FIG. 4 uses a spring and a long screw as a portion for pressing the wiping material. Similarly, the same parts as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted. A female screw 16 is screwed on one side of the frame 5, and a long screw 18 having a clamp 17 attached to one end is screwed into the female screw. The other end of the long screw 18 is in contact with the pressing plate 19. A guide 7 is disposed at the tip of the pressing plate 19, and a compression spring 20 is installed between the pressing plate 19 and the guide 7. The guide 7 and the holding body 8 are connected to each other by a connecting rod 14 such that the guide 7 and the holding body 8 are swingable. A wiping material 9 is attached to the holding body 8. In the rolling mill of FIG. 4, the pressing state of the wiping material on the roll is adjusted by the screwed state of the long screw and the spring.

  Table 1 shows the characteristics of the foam solder (referred to as wiped foam solder) obtained by the rolling method of the present invention and the foam solder (referred to as unwiped foam solder) obtained without wiping the oxidized powder on the roll surface.

表１の説明
※１：表面酸化膜の厚さ
分析装置：XPS
分析内容：イオンスパッタリング法による深さ方向分析
※２：濡れ広がり性
はんだペレットを基板（ニッケルメッキを施した銅基板）上に載せ、水素窒素混合ガス雰囲気中にてリフローする（230℃以上3分間、ピーク温度280℃、総リフロー時間15分間）。リフロー前のペレットの面積に対するリフロー後のはんだの濡れ面積比を算出。
※３：変色
大気雰囲気中でフォームはんだのリフロー後に、はんだの表面が黄色に変色（黄変）しているか、否か、を観察する。黄変した場合は、外観が悪くなるため商品価値が下がる。

Explanation of Table 1 * 1: Surface oxide film thickness Analyzer: XPS
Details of analysis: Depth direction analysis by ion sputtering method * 2: Wet spreadability Solder pellets are placed on a substrate (copper substrate with nickel plating) and reflowed in a hydrogen-nitrogen mixed gas atmosphere (230 ° C or more for 3 minutes) , Peak temperature 280 ° C, total reflow time 15 minutes). Calculate the ratio of wetted area of solder after reflowing to the area of pellets before reflowing.
* 3: Discoloration Observe whether or not the solder surface has turned yellow (yellowing) after reflow of foam solder in the atmosphere. When yellowing occurs, the product value decreases because the appearance deteriorates.

  As can be seen from Table 1, the wiped foam solder had less surface oxide powder adhesion, exhibited sufficient wetting and spreading in the spreading test, and did not yellow. On the other hand, the unwiped foam solder had a large amount of oxidized powder on the surface, poor wetting and yellowing.

  The present invention is suitable for rolling a solder material, but can also be applied to rolling not only a solder material but also a soft material such as a fuse, a tin foil, and a lead foil. In the solder material, the oxidized powder adhering at the time of rolling becomes a problem, but in other soft materials, the surface color gloss or scratches due to the metal powder remaining on the surface when it becomes the final product becomes a problem.

Front sectional view of the solder rolling mill of the present invention The perspective view of the press apparatus installed in the rolling mill for solder of this invention Front sectional view of another embodiment of the solder rolling mill of the present invention Front sectional view of still another embodiment of the solder rolling mill of the present invention.

Explanation of symbols

1, 2 rolls 3 solder material 4 pressing device 6 air cylinder 9 wiping material

Claims (7)

  Oxidation of solder adhering to the roll surface by pressing the roll surface of the rolling mill with a soft wiping material having a concave surface with substantially the same arc as the roll of the rolling mill and wide in the circumferential direction of the roll. A method for rolling solder, comprising rolling a strip-shaped solder material while wiping the powder with the wiping material.   The end of the pressing device that can adjust the pressing force has a concave surface of substantially the same arc as the roll of the rolling mill, and is attached with a soft wiping material that is wide in the circumferential direction of the roll, The wiping material is capable of wiping away the oxidized powder of solder adhering to the roll by pressing the roll surface of the rolling mill.   The rolling mill for solder according to claim 2, wherein the wiping material on the concave surface has a width in the circumferential direction of the roll of 10 to 50% of the circumferential length of the roll.   3. The rolling mill for soldering according to claim 2, wherein the pressing device has a concave surface that presses the wiping material so as to follow the position of the roll of the rolling mill.   5. The solder rolling mill according to claim 2, wherein a portion of the pressing device that presses the wiping material against the roll surface is an air cylinder.   5. The rolling mill for soldering according to claim 2, wherein a portion of the pressing device that presses the wiping material against the roll surface is a long screw. The solder rolling mill according to claim 2, wherein a portion of the pressing device that presses the wiping material against the roll surface is a spring.

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