JPS648070B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION According to known molten solder coating methods, such as dipping, centrifugation, roller or wave methods, molten tin or tin-lead alloys are used to coat metal parts with a solderable layer. However, it is not possible to coat such layers with sufficient tolerances required by many solderable electronic components. Another disadvantage of these methods is that the molten solder that has entered the holes, recesses, etc., is either impossible or very difficult to remove from these recesses later.

It is an object of the present invention to be able to coat metal materials or components with a solderable layer from molten tin or tin-lead alloys with narrow tolerance layer thicknesses, and to be able to apply solderable layers to metal materials or components from molten tin or tin-lead alloys. The object of the present invention is to propose a method and a device in which solder coating is also possible completely or partially.

The purpose is to introduce molten solder on one or both coated sides of a coated metal material or component in contact with one or more wicks made of wicking material, and to introduce the molten solder into the capillary action of the heated wicks. This problem has been solved by a method in which the molten solder layer of a metal material or component is continuously sucked up to a predetermined layer thickness in a controllable manner, and the excess molten solder that has been sucked is guided into the molten solder bath through the capillary tube of a sucker. Ru.

By guiding a metal material or component coated with molten solder along a blotting blotting device, it has become clear that the thickness of the molten solder layer can be controlled very accurately by the capillary action of the heated wicking device. Ta. The molten solder layer is sucked off, especially in the upper region of the suction device, and excess molten solder flows down through the capillary tube. In this case, it has proven advantageous to immerse at least the part of the blotting device below the blotting surface in a height-adjustable manner in a heated tin or tin-lead alloy bath, and to maintain the bath level constant. It became. Thereby a continuous suction force is generated which can be adjusted very precisely and controls the thickness of the molten solder layer remaining on the metal material or component in relation to the speed of passage of the metal material or component to be suctioned. be able to.

With such a method of the invention, plates, tubes and small flat mass-produced parts can be coated with molten solder with narrow tolerances by suitable feeding devices. In particular, solder that has flowed into holes or similar areas is removed by suction. In the case of the method of the invention, it is advantageous to press the wick lightly against the metal material or component to be desoldered, thereby ensuring that the metal material or component is in reliable contact with the wick. .

According to the proposal of the invention, a blotting device is used consisting of a compressed wire fabric or steel wool or a wire brush that can be tinned but is not dissolved by the tin. Such block or roll-shaped suction devices can be reinforced with mandrels or perforated coverings.

In order to coat flat stamped metal parts or plates with solder in a solderable manner, the present invention has a heatable solder tank whose height can be adjusted, and a molten solder bath in the tank is heated. An apparatus is used which is characterized in that a blotting device made of blotting material is arranged in a partially immersed manner, in contact with which a blotting surface above the bath surface the part coated with molten solder is guided. This suction device, in particular made of a compressed metal fabric, has an upwardly opening suction slit through which the metal material or component to be soldered is guided in contact with the sides of the slit. Such equipment can additionally be covered by an inert gas hood that maintains an inert gas atmosphere during coating of the molten solder.

By varying the height of the bath surface relative to the suction surface of the suction device above it, the suction force is adjusted, whereby the layer thickness of the molten solder layer is controlled with very high tolerances.

Next, embodiments of the present invention will be described with reference to the drawings.

A solder bath 1, shown in longitudinal section in FIG. 1, is heated by a heating device 2, so that the solder attains a temperature of approximately 260°C. In the chamber 3 of the solder bath 1, the metal strip material 4 is coated with molten solder through rollers 5, 6 and 7 and is drawn off through a suction device 9 by a winding device 8. In the chamber 10 of the solder bath 1, the suction device 9 is immersed in the solder bath such that there is a height difference of approximately 10 to 40 mm between the surface of the metal strip material and the surface of the solder bath. Since the lower area of the wick 9 is in the solder bath, the capillary action of the sponge-like metal wick leads excess solder wicking from the surface of the metal strip material into the solder bath.

The difference in height between the metal strip material surface and the solder bath surface is 10 mm.
at 30-40 microns, other conditions being the same 40
A solder film with a thickness of 5 to 8 microns in mm is obtained on the surface of the metal strip material.

In order to absorb the upper surface of the metal strip material in the same way,
As can be seen in the cross section of the figure, the device according to the invention also comprises an upper suction device 11 . The upper suction device 11 has an inverted U-shaped cross section, and the free ends of the two legs 12 of the U are immersed in the solder bath 10 to guide excess solder into the solder bath 10. The means for adjusting the desired height difference are not shown.

It is an advantage of the invention that instead of smooth metal strip materials, strip materials with perforations can also be solder-coated. The device of the present invention eliminates uneven solder distribution (solder build-up on punched edges, solder blocking punched holes or narrow slits) when such strips are immersed in a solder bath to a very small size of 7 to 15 microns. It can be blotted to obtain uniform solder distribution and open holes or slits. The suction devices 9 and 11 are arranged slightly elastically with respect to each other,
Advantageously, the solder bath is kept airtight by means of a hood 13.

According to FIGS. 3 and 4, a metal part for coating the solder, for example a tap 1 provided with a hole 17b.
The flat sheet metal part 17 with 7a has already been coated with a layer of molten solder in a known manner, in particular by immersion in molten tin or a molten tin-lead alloy, and this layer is subsequently coated with a layer thickness to a predetermined tolerance. do.

For this purpose, the component 17 is led into the bath 15 in a heated state, which still has a molten solder coating of uneven thickness on its outer surface, as shown in FIGS. This tank is heated by a heating device 14. In this case, the height of the bath surface of the solder bath 19 is adjustable and can be kept constant at any desired height. A suction device 16 is placed in the bath with its lower part 16c immersed in the bath.

This suction device 16, which is constructed in the form of a block of compressed absorbent wire fabric, has an upwardly opening slit 16d through which the part 17 is guided in contact with the slit. In this case, the suction surfaces 16a and 16b come into contact with the surface of the component 17 coated with molten solder.

Due to the capillary action of the suction device 16, a uniform suction force is applied to the molten solder coating, and the metal is suctioned to a desired degree, and the suctioned metal is transferred to the solder metal bath 19.
through a capillary tube to the lower part 16c of the blotting device, where it is immersed in water. The material of the blotting device is particularly wettable to the molten solder metal, so when the capillary tube comes into contact with the molten metal layer of the component, capillary action occurs and excess molten solder is sucked up by the wicking device. A continuous flow of wicking molten solder towards metal bath 19 occurs.

It is advantageous to carry out the treatment in an inert gas atmosphere to avoid oxidation. Therefore, the solder bath 15 and the suction device 16 are covered with an inert gas hood.

It is also advantageous to use other types of wicker instead of wicker blocks of this type. For example, suction rolls made of a suitable absorbent material are used, and the metal material or component coated with molten solder is passed between the rolls, optionally with pressure applied to the rolls. This roll is preferably driven in this case, the lower part of which is immersed in a bath of molten solder. Instead of forming such a roll of textile material, a plate-like structure is also possible.

As described above, the present invention has the following remarkable effects.

(1) After passing the metal material or part into the molten solder bath and covering all the desired parts with molten solder, remove the excess on the metal material or part through the capillary tube of a suction device made of absorbent material and equipped with a capillary tube. Since the molten solder is sucked up and introduced into the molten solder bath, for example, both end surfaces of the metal material or component or the peripheral wall surface of the hole are coated uniformly, unlike when a thin wire bundle with capillary tubes is used to coat the end surfaces of the metal material or component. The molten solder adhering to those parts is uniformly sucked into the suction device by capillary action caused by the surface tension, so the thickness of the solder layer is smaller than that of the other parts. can be controlled in the same way as the layer thickness.

(2) The thickness of the coating layer can be adjusted by adjusting the height of the bath surface of the molten solder bath, in other words, by adjusting the difference in height between the suction surface of the suction device and the bath surface. Adjustment of the layer thickness of the molten solder layer on the metal material or component can be easily and accurately carried out using very simple means.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of the molten solder coating apparatus for metal strip materials according to the present invention, FIG. 2 is a cross-sectional view thereof, FIG. 3 is a longitudinal sectional view of the molten solder coating apparatus for plate-shaped parts, and FIG. FIG. 1, 15... Solder bathtub, 2, 14... Heating device, 3, 10, 19... Solder bath, 4... Metal strip material, 9, 11, 16... Blotter, 13... Hood, 17... ...Metal plate parts.

Claims (1)

[Scope of Claims] 1. After continuously coating a metal material or part with molten solder, the coated metal material or part is made of an absorbent material on one or both sides thereof and has a capillary tube. Alternatively, the lower end can be guided in contact with a number of suction devices, and the lower end can adjust the position of the bath surface. To adjust the coating solder layer thickness by continuously sucking up the solder to a constant layer thickness, guiding the sucked up excess molten solder to the molten solder bath through the capillary tube of the sucker, and adjusting the position of the bath surface. A method of continuously molten coating a metal material or component with a solderable layer of tin or a tin-lead alloy, characterized in that: 2. The method according to claim 1, wherein at least a portion of the blotting device below the blotting surface is immersed in a molten tin or tin-lead alloy bath with an adjustable immersion depth. 3. The method according to claim 1, wherein the sucker is lightly pressed against the metal material or component whose solder is to be sucked. 4. A method according to claim 1, in which a blotting device made of compressed wire fabric, steel wool, wire brush, etc., which is solderable but not dissolved by tin, is used. 5. Directing a metal material or component coated with molten solder through an absorbent suction roller partially immersed in a molten solder bath.
The method described in any one of the paragraphs. 6. A heatable solder bath 1, 15 capable of controlling the height of the molten solder bath surface, and a 1 made of absorbent material and having a capillary tube placed in the solder bath and partially immersed in the molten solder bath. one or more suction devices 9, 11, 16; a metal material or part 4;
After passing through the molten solder bath, the device continuously conveys the solder while contacting the suction surface of the suction device at a position higher than the bath surface, and the capillary action of the suction device removes the excess on the metal material or parts. Apparatus for continuously melt-coating metal materials or components with a solderable layer of tin or tin-lead alloy, characterized in that the molten solder is introduced into the bath through the capillary tube of a blotting device. 7. A patent in which a suction device 16 made of compressed metal fabric has a suction slit 16d that opens upward, and the metal material or component 17 to be de-soldered passes through the slit while contacting the side surfaces 16a and 16b of the slit. An apparatus according to claim 6. 8 Solder bath 1, 15 and/or blotting device 9, 1
8. The apparatus according to claim 6, wherein 1 and 16 are covered with an inert gas hood 13.