JPH0757420B2 - Manufacturing method of lead pin with silver solder - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement in a method for manufacturing a lead pin with silver brazing, and more specifically, to a head portion of a lead pin having an enlarged head portion to be attached to an electronic component. The present invention relates to a method of providing a silver solder in a hemispherical shape.

[Conventional technology]

Conventionally, this type of lead pin manufacturing method has been disclosed in Japanese Patent Publication No. 63-51.
As disclosed in Japanese Patent No. 543 (the embodiment is shown in FIG. 5), a nail-shaped lead pin a having a flat head a '.
A prepared hole b ′ having a diameter smaller than the diameter of the head and larger than the leg a ″ and deeper than the length of the leg, and an upper hole b ″ having a diameter larger than the diameter of the head and equal to or deeper than the height of the head.
Inserted into the rivet-shaped hole of the carbon jig c having the rivet-shaped hole b consisting of and suspended, and then placing the silver brazing tip d on the upper surface of the head a ′ in the upper hole b ″. Next, there is provided a method in which the carbon jig c is put in a furnace and heated to melt the silver brazing chips and bond them to the upper surface of the head, but the prepared hole and the prepared hole are formed in a stepped shape. Has a fine lead pin (0.45 mmφ) in the minute pilot hole (0.7 mmφ)
It is difficult to insert the legs of the robot, and especially in the case of automation in mass production, the legs may collide with the lower surface of the upper hole and bend, so highly accurate position setting is required,
When the manufacturing equipment becomes more accurate, the cost becomes higher. On the other hand, when the leg is set large with some allowance so that it can be easily inserted into the pilot hole, the leg is eccentric to the pilot hole. Frequent hanging in the state may result in molten silver wax flowing into the sides of the head and failing to achieve its original purpose. In addition, since the head of the lead pin is formed by crushing the end of the wire rod, the diameter of the lead pin inevitably has a dimensional variation within the allowable range for each product, and therefore the diameter of the upper hole absorbs the variation. It must be set large with a margin to obtain, and as a result, depending on the product, a large gap is created between the periphery of the head and the inner surface of the upper hole, and the molten silver wax flows into the gap and the head There was a risk of defective products with silver solder around the area. Furthermore, there is a restriction that the diameter of the head of the lead pin must be sufficiently larger than the diameter of the prepared hole, and the shape of the lead pin that can be processed is limited.

[Problems to be Solved by the Invention]

In view of the above situation, the present invention is to solve the problem in that the lead pin can be easily attached to the jig without rattling or deviation, and the head diameter has dimensional variation within an allowable range. It is possible to improve the non-defective rate by supporting the periphery of the head in a tightly fitted state and preventing the flow of the silver solder from the side surface of the head to the lower surface when the silver solder piece placed on the upper surface of the head is melted. Another object of the present invention is to provide a method of manufacturing lead pins with silver brazing which can be used and can be automated in mass production.

[Means for Solving the Problems]

In order to solve the above-mentioned problems, the present invention provides a lead pin having a disk-shaped enlarged head and a columnar leg, and an upper opening edge having an inner diameter larger than the diameter of the head and the diameter of the leg. Has a tapered hole formed by connecting an inner hole having an inner diameter substantially equal to that of the tapered hole, and a parallel support hole formed vertically below the tapered hole and coaxially connected to the inner hole. The depth of the tapered hole is larger than the length of the lead pin. Inserted from the leg into the tapered hole of the jig that is shallowly set, the head is tightly fitted to the upper part of the tapered hole and suspended, and the leg is fitted into the support hole, Next, a silver brazing piece is placed on the upper surface of the head, and the head of the lead pin and the silver brazing piece are heated, and the silver brazing piece is melted and joined to the upper surface of the head. The manufacturing method of

Further, with the lead pin inserted into the tapered hole and the support hole of the jig and the silver brazing piece placed on the upper surface of the head of the lead pin, the jig is passed through a heating furnace or the upper surface of the jig is burned. It came to heat with the flame or hot air.

Further, at least the upper part of the jig is preheated before the silver brazing piece is placed on the upper surface of the head of the lead pin attached to the jig.

[Action]

According to the method for manufacturing a lead pin with silver brazing of the present invention having the above contents, when the lead pin leg portion is inserted into the upper opening edge of the tapered hole provided perpendicularly to the jig, the lead pin longer than the depth of the tapered hole is a leg. The lower end of the part fits into a parallel support hole continuously formed below the tapered hole while being guided by the inner surface of the tapered hole, and at the predetermined height portion of the tapered hole having an inner diameter matching the diameter of the head part. The lead pin is suspended in the fitted state, that is, the lead pin is coaxially and substantially vertically supported with respect to the tapered hole and the support hole, and in this state, when the silver brazing piece placed on the upper surface of the head is melted, the silver brazing piece is melted. Although it spreads to the periphery of the head, the inner surface of the tapered hole that is in close contact with the periphery of the head reliably regulates the inflow of the silver solder from the side surface of the head to the lower surface.

Also, by preheating the upper part of the jig with the lead pins attached to the tapered hole and the support hole of the jig,
The heads of the lead pins and the silver brazing pieces having different specific heats are heated to substantially the same temperature to complete the joining.

〔Example〕

Next, the details of the present invention will be described based on the embodiments shown in the accompanying drawings.

FIG. 1 shows a typical embodiment of the present invention, in which 1 is a lead pin, 2 is a jig, and 3 is a silver brazing piece.

The lead pin 1 extends a long wire wound around a drum and compresses one end in the axial direction to crush it to form a disk-shaped expanded head 4 and cut it to a predetermined length to form a leg. The part 5 is formed. Therefore, the diameter of the head portion 4 inevitably varies within the allowable range, but the diameters of the leg portions 5 are accurately aligned. The size of the lead pin 1 used in this embodiment is such that the diameter of the head 4 is 0.7 mm.
φ, its thickness is 0.2 mm, and the leg 5 has a diameter of 0.6 mm φ and its length is 4.5 mm, but various dimensions are available depending on the size of the device such as a semiconductor integrated circuit, that is, the degree of integration. However, the size thereof tends to become smaller with the recent high integration, and the usefulness of the present invention is particularly emphasized. The present invention can be applied to the lead pin 1 having any size as long as the diameter of the head 4 is larger than the diameter of the leg 5. Further, the material of the lead pin 1 is often Fe—Ni alloy, but is not particularly limited and it is natural that a material having a melting point higher than the melting point of silver brazing material described later is used.

The jig 2 has an upper opening edge 7 having an inner diameter larger than the diameter of the head portion 4 of the lead pin 1 on the upper surface 6, and an inner hole having an inner diameter substantially equal to the diameter of the opening edge 7 and the leg portion 5 of the lead pin 1. 8
A continuous tapered hole 9 and a parallel support hole 10 which is continuous and coaxial with the inner hole 8 below the tapered hole 9 are vertically penetrated vertically to form a large number of them. It is a thing. Further, the depth L ₂ of the tapered hole 9 is set to be shallower than the length L _{1 of the} lead pin 1, and in this embodiment, the depth L ₃ of the support hole 10 is set lower when the leg portion 5 of the lead pin 1 is inserted. It is set so that it does not stick out. This is because when the leg portion 5 projects below the jig 2, the lead pin 1 mounted on the jig 2 moves or touches the projecting portion of the leg portion 5 unexpectedly when handling the jig 2. This is to prevent falling off. Further, as shown in FIG. 2, the inclination angle α of the taper hole 9 is set such that the upper edge of the outer peripheral surface of the head 4 and the taper hole 9 are different from each other.
The inner surface 11 is set to a small size so as not to create a gap into which silver brazing can flow, and in this embodiment, it is set to a minute angle of 0 degrees 52 minutes 5 seconds. When the taper hole 9 has a straight and simple shape, the angle is substantially determined according to the diameter of the head and the length of the leg 5, but the head 4
The angle of the tapered hole 9 in the part where
It is also possible to set different angles with the support holes 10. The jig 2 is preferably made of carbon, which has no wettability with silver solder, but stainless steel, molybdenum, or the like can be used.

The silver brazing piece 3 is obtained by cutting a wire material of Ag-Cu 28 wt% into an appropriate length according to the area of the head 4 of the lead pin 1.
The alloy ratio and shape are not particularly limited.

Then, silver brazing solder is formed on the upper surface of the head portion 4 of the lead pin 1 in a hemispherical shape. First, from the leg portion 5 of the lead pin 1 to the upper opening edge 7 of the tapered hole 9 of the jig 2. It is inserted and fitted into a support hole 10 formed continuously below the tapered hole 9 and suspended vertically in a tight fit state on the inner surface 11 of the tapered hole 9 corresponding to the diameter of the head 4. Then, the upper surface of the head 4 and the inner surface 11 of the opening edge 7 of the tapered hole 9 form a recess having a predetermined depth.
Next, in this state, the silver brazing piece 3 cut into a predetermined amount is placed on the upper surface of the head 4, and the jig 2 is put in or passed through a heating furnace such as an electric furnace. The silver brazing piece 3 is melted and bonded to the head portion 4. At this time, the silver brazing material spreads in a hemispherical shape having a bulged central portion on the entire upper surface of the head portion 4 due to surface tension. The inner surface of the tapered hole 9 of the jig 2 having a low wettability with respect to the brazing restricts the inflow to the side surface of the head 4, and the silver brazing is truly melt-bonded only to the upper surface of the head 4. Then after cooling, the support holes
The lead pin 1 is taken out above the lead pin 1 by a push rod inserted from below into the lead pin 1, and the lead pin 1 with silver brazing in which a hemispherical silver braze 3'is provided on the upper surface of the head 4 is manufactured as shown in FIG. Here, although not shown, the push bar is a plate-shaped jig provided with a large number of protrusions at the same height as the support holes 10 and at the same height. The push rod is inserted into the support hole 10. In the automation of the manufacturing apparatus, the jig 2 having the lead pin 1 mounted thereon is more preferable than the case where the jig 2 is placed in a heating furnace.
In some cases, it may be more efficient to heat the upper surface 6 of the above with a burner flame or hot air, and the heating means shall be adopted appropriately.

Further, due to the difference in specific heat due to the difference in material between the lead pin 1 and the silver brazing piece 3 and heat conduction due to the contact between the lead pin 1 and the jig 2, the head 4 of the lead pin 1 and the silver brazing piece 3 are Since there is a difference in temperature rise, at least the upper part of the jig 2 is preheated with the lead pin 1 mounted on the jig 2, and then the silver brazing piece 3 is placed on the head 4 and heated again to heat the head. It is possible to bond more firmly by raising the temperature of the silver brazing piece 4 and the silver brazing piece 3 to substantially the same temperature and performing the melt bonding.

Further, as another embodiment, the one shown in FIG. 4 is the same as the above-mentioned embodiment except that the jig 2 is divided into an upper jig 2a and a lower jig 2b at an appropriate position in the middle of the support hole 10. When the lead pin 1 is inserted into the taper hole 9 and the support hole 10, the divided portion is set so that the lower end of the leg 5 is located in the support hole 10 of the lower jig 2b. After joining the silver solder 3'on the upper surface of the head 4, the upper jig 2a and the lower jig 2b are separated, and the leg portion 5 projecting downward from the upper jig 2a is pushed up so that the push rod is not used. The lead pin 1 can be easily taken out from the jig 2. The lower jig 2b can be omitted if there is no fear that the leg portion 5 protruding downward from the upper jig 2a is inadvertently contacted during the manufacturing process.

〔The invention's effect〕

According to the method for manufacturing a lead pin with silver brazing of the present invention as described above, a lead pin having a disk-shaped expanded head and a columnar leg is provided with an upper opening edge having an inner diameter larger than the diameter of the head. And a tapered hole in which an inner hole having an inner diameter substantially equal to the diameter of the leg portion is continuous, and a parallel support hole which is continuous and coaxial with the inner hole is formed below the tapered hole, and the lead pin is provided. Insert the leg into the taper hole of the jig with the depth of the taper hole set to be shallower than the length, and suspend the head from the upper part of the taper hole in a tightly fitted state and support the leg. Fit into the hole, then place the silver solder piece on the top surface of the head, and heat the lead pin head and the silver solder piece to melt the silver solder piece and bond it to the top surface of the head. Therefore, simply insert the leg of the lead pin from the upper opening edge of the tapered hole, The portion is guided by the inner surface of the tapered hole and fits into the support hole, and the head can be suspended and tightly fitted on the inner surface of the tapered hole, and the diameter of the head is within the allowable range. Even if there is a dimensional variation, it is possible to maintain a constant support state at all times, and in that state, it can be automatically positioned coaxially with the tapered hole and the support hole, and at the upper edge of the outer peripheral surface of the head. Since the inner surfaces of the tapered holes are close to each other, even if the silver brazing piece placed on the upper surface of the head is melted, the silver brazing material does not flow from the side surface of the head to the lower surface, and the good product rate is improved. In addition, it is possible to always join the silver brazing material to the upper surface of the head in a hemispherical shape having the same shape. Further, since the inner diameter of the opening edge of the tapered hole can be set to be sufficiently larger than the diameter of the leg portion of the lead pin, high accuracy is not required for position determination when inserting the lead pin into the tapered hole, and automation of manufacturing structure It is possible to reduce the cost and the work time for inserting the lead pin into the tapered hole, and thus to suppress the cost increase of the lead pin with silver brazing.

Further, by preheating at least the upper portion of the jig with the lead pin attached to the jig, the silver brazing piece to be subsequently placed on the upper surface of the head and the head are heated to substantially the same temperature at substantially the same time. Therefore, the head and the silver solder can be joined more firmly.

[Brief description of drawings]

FIG. 1 is a partial vertical sectional side view showing a typical embodiment of the present invention,
FIG. 2 is an enlarged cross-sectional view of the main part, FIG. 3 is a side view of a lead pin with silver brazing produced according to the present invention, FIG. 4 is a partial vertical side view showing another embodiment, and FIG. 5 is a conventional example. FIG. 1: lead pin, 2: jig, 3: silver brazing piece, 4: head, 5: leg,
6: Top surface, 7: Opening edge, 8: Inner hole, 9: Tapered hole, 10: Support hole, 11: Inner surface.

Claims (4)

[Claims] 1. A lead pin having a disk-shaped expanded head portion and a columnar leg portion is provided with an upper opening edge having an inner diameter larger than the diameter of the head portion and an inner hole having an inner diameter substantially equal to the diameter of the leg portion. Has a continuous tapered hole and a parallel support hole which is continuous and coaxial with the inner hole below the tapered hole, and the depth of the tapered hole is set to be shallower than the length of the lead pin. The jig is inserted into the tapered hole from the leg, and the head is suspended from the upper part of the tapered hole in a tightly fitted state, and the leg is fitted into the support hole. A silver brazing piece is placed on the head, and the head of the lead pin and the silver brazing piece are heated, and the silver brazing piece is melted and joined to the upper surface of the head. Method. 2. A jig is inserted into a tapered hole and a support hole of the jig, and the jig is passed through a heating furnace with a silver brazing piece placed on the upper surface of the head of the lead pin. A method for producing a lead pin with silver brazing as set forth in claim 1. 3. A lead pin is inserted into the tapered hole and the support hole of the jig, and a silver brazing piece is placed on the upper surface of the head of the lead pin, and the upper surface of the jig is exposed to burner flame or hot air. The method for producing a lead pin with silver brazing according to claim 1, which is formed by heating. 4. A lead pin having a disk-shaped expanded head portion and a columnar leg portion is provided with an upper opening edge having an inner diameter larger than the diameter of the head portion and an inner hole having an inner diameter substantially equal to the diameter of the leg portion. Has a continuous tapered hole and a continuous parallel support hole vertically below the tapered hole and coaxial with the inner hole, and the depth of the tapered hole is set to be shallower than the length of the lead pin. Inserted from the leg into the tapered hole of the tool and suspending the head from the upper part of the tapered hole in a tightly fitted state, and fitting the leg into the support hole, and at least in the state of the jig. Preheating the upper part, then placing a silver brazing piece on the upper surface of the head, and heating the head of the lead pin and the silver brazing piece, melting the silver brazing piece to bond it to the upper surface of the head. A method of manufacturing a lead pin with silver brazing, which comprises: