JP2009166067A - Iron tip for lead-free solder, and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reliably prevent any rise of a solder, and to ensure the correctness of a soldering work using a lead-free solder, in particular, by an industrial robot by ensuring the uniformity of the solder feed. <P>SOLUTION: An iron plating layer (14) formed as a base plating, a hard chromium plating layer (16) formed on the surface of the iron plating layer except a contact surface (P) with a solder, and a black chromium plating layer (18) formed thereon in a superposing manner are provided on the entire surface of a base body (12) of an iron tip (10). A preliminary solder (22) and a non-heat-resistant resin (24) to cover the preliminary solder are formed on the iron plating layer of the solder contact surface part. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a soldering iron tip and a method of manufacturing the same, and more particularly, low-temperature soldering work using lead-free solder, particularly soldering work performed using lead-free solder using an industrial robot. In order to ensure the accuracy and speed of soldering work by preventing the phenomenon of solder rising in addition to the tip of the soldering iron and improving the corrosion resistance against chemicals, etc. The present invention relates to a soldering iron tip and a manufacturing method thereof.

  Soldering is a type of metal welding in which a compound metal film is formed and bonded to the metal surface when the soldering object and solder (hereinafter referred to as “soldering object etc.”) are heated to the solder melting temperature. The role of the soldering iron is to supply an amount of heat for warming the soldering object etc. to the solder melting temperature.

  A conventional iron tip is used by being attached to a heater portion having a heating element provided at the tip of a soldering iron main body, and the base, which is the basic structure of the iron tip, uses a copper material, for example, a pen. It is formed in a tip shape.

  A copper material having good thermal conductivity is used for the base of the iron tip, and tough pitch copper and phosphorous deoxidized copper have been often used for this copper material. Here, when the iron tip is composed only of a copper material, there is a problem that the copper material is strongly oxidized by heating and is worn out in a short time due to erosion by tin which is a soldering material. Therefore, in order to protect the copper material and to improve the wettability with the solder, the entire surface of the copper substrate is generally subjected to iron plating.

However, if iron plating is only applied to the surface of the tip of the iron tip, an insoluble scale may be formed at the tip of the iron tip, which may hinder the next solder from being melted. In addition to this, there was a phenomenon in which the solder was raised, which hindered the soldering work.
For this reason, a soldering tip or the like in which a hard chromium plating layer is formed on the surface of the iron plating layer excluding the contact surface with the solder and resistance to the flux contained in the solder is increased.

  Further, for example, a chrome plating (hard chrome plating) is applied in addition to the state of the iron-plated base as in the “soldering tip” in Patent Document 1 and Patent Document 2, and the entire iron tip is plated with aluminum. Invented inventions have also been proposed.

  By the way, in recent years, the shift from leaded solder to lead-free solder has been increasing due to regulations based on environmental issues. Lead-free solder is a solder that works at a lower temperature than lead-free solder, while lead-free solder, which is a conventional general solder, has a working temperature range of 450 to 500 degrees Celsius, while lead-free solder The working temperature range is around 350 degrees. This is because general leaded solder itself has a melting point of 180 to 230 degrees, but if it is operated at a high temperature (450 to 500 degrees or more), the solder melts quickly. On the other hand, the work temperature range of lead-free solder is as low as around 350 ° C. Even if high-temperature work is performed with lead-free solder, high-temperature oxidation of the solder is remarkable and a strong oxide film is formed. As a result, the phenomenon of soldering occurs and the work itself cannot be performed, and the degree of wear of the tip is extremely accelerated from around 380 degrees, and the production line is too costly to enter the mass production system. This is due to reasons such as it takes.

Also, in recent years, automation of soldering work has expanded, and soldering work using lead-free solder by industrial robots that require precise and quick soldering has increased in addition to the cutting edge of the iron tip. Therefore, it is necessary to effectively prevent the phenomenon that hinders the soldering work. In other words, in the soldering work using an industrial robot, it is necessary to perform soldering at a relatively low temperature within a short time in a narrow range that is fixed in the amount of solder used for soldering. However, the tip of an iron plate with an iron plating layer formed on the substrate has not been sufficiently resistant to corrosion by chlorine in the flux. Further, even with a soldering tip in which a hard chrome plating layer is further formed on iron plating, there is a problem that the corrosion resistance and chemical resistance of the hard chrome plating are low in the region of about 350 degrees.
Japanese Utility Model Publication No. 43-2959 Japanese Utility Model Publication No. 43-5861

  As described above, in the soldering work performed using the lead-free solder using the industrial robot, it is necessary to perform the work by placing an optimum amount of solder only on the desired most advanced portion of the iron tip. If the soldering phenomenon continues on the tip of the soldering iron other than the cutting edge, the hard chromium plating or the like is corroded by the flux in the soldering, and as a result, the accuracy of the work may be impaired. Further, when the durability of the soldering tip is low, it is necessary to frequently replace it, and the workability is also deteriorated, so that the cost of soldering is increased.

  The present invention was devised to solve the above-mentioned problems. In the soldering work using a lead-free solder using a lead-free solder, especially in the soldering work performed using the lead-free solder by an industrial robot, the tip of the tip is used. In addition to preventing the phenomenon of solder rising more effectively, the soldering work accuracy is ensured by placing an optimal amount of solder only on the desired tip of the iron tip, An object of the present invention is to provide a lead-free soldering iron tip capable of suppressing an increase in soldering cost by increasing the durability of the iron tip and a method for manufacturing the same.

In order to achieve the above object, the present invention provides an iron plating layer (14) applied as a base plating to the entire surface of the base (12) of the iron tip (10) and the iron plating excluding the contact surface (P) with the solder. There is provided a lead-free soldering iron tip having a hard chrome plating layer (16) applied on the surface of the layer and a black chrome plating layer (18) applied thereon.
Black chrome plating, unlike hard chrome plating, consists of metal chrome and chromium oxide (a lower oxide of chromium) and cannot be applied thickly and has low hardness, but low solder wettability and high Corrosion resistance and heat absorption.

  Here, it is preferable to deposit the non-heat-resistant resin (24) on the iron plating layer (14) of the solder contact surface (P) portion so as to cover the pre-solder (22) and the pre-solder.

  In addition, the said base | substrate (12) is an oxygen free copper and the said iron plating layer (14) shall have a film thickness of 200 micrometers-1500 micrometers.

  In the present invention, the entire surface of the base (12) of the iron tip (10) is subjected to iron plating (14) as a base plating, and the surface of the iron plating layer excluding the contact surface (P) with the solder is plated with hard chromium (16 And a method for producing a lead-free soldering iron tip characterized by being provided with black chrome plating (18) on top of this.

  Here, preliminary solder (22) is applied onto the solder contact surface (P) of the base (12) subjected to iron plating (14), and non-heat-resistant resin (24) covering the preliminary solder is applied thereon. It is preferable to wear.

According to the present invention, by applying hard chromium plating and black chrome plating on top of this to the surface of the iron plating layer excluding the most advanced surface (contact surface with the solder) of the base plated with iron over the entire surface, Its low wettability (high solder repellent property) can reliably prevent solder rise, and it can prevent corrosion more effectively due to its higher chemical resistance than hard chrome, especially the accuracy of soldering work by industrial robots By assuring the uniformity of the solder supply amount, it is possible to further secure the solder supply amount, and at the same time, to greatly reduce the wear of the iron tip and to realize a reduction in the total cost in the production line.
The double plating of hard chrome plating and black chrome plating exhibits the above-described excellent effect mainly in lead-free soldering work in which the working temperature range is about 350 degrees.

  Here, by applying non-heat-resistant resin on the iron-plated layer of the solder contact surface portion so as to cover the spare solder, the most advanced solder contact surface of the tip contacts the air before the start of use. In addition to preventing oxidation due to this, it can also be used as a mask to prevent the formation of a plating layer in this portion during the manufacture of the tip.

When tough pitch copper or the like is used for the base, the oxygen inside the copper material thermally expands, which may cause the iron plating to bulge and reduce the thermal conductivity of the iron tip. With oxygen, oxygen-free copper has very good adhesion of iron plating without pinholes, cracks and gas generation, and there is no swelling and peeling (annular faults) in the iron plating structure even at high temperatures, Plating peeling and solder wettability degradation caused by a fault can be avoided.
Further, by setting the film thickness of the iron plating layer to 200 μm to 1500 μm, it is possible to balance the life extension of the iron tip and the reduction of the manufacturing cost.

  The present invention provides accurate soldering work using lead-free solder, which is performed at a low temperature (around 350 degrees) compared to leaded solder, particularly using lead-free solder using an industrial robot. The present invention relates to a lead-free soldering iron tip and a method for manufacturing the same to ensure the reliability and speed. Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

First, FIG. 1 shows a soldering iron body 31 provided at the tip of an industrial robot arm, and a lead-free soldering iron tip 10 of the present invention used by being attached thereto. This soldering iron body 31 is attached to the tip of a robot arm 33 that performs a predetermined operation according to a program, and a round bar-like heater portion 35 extends from the tip of the robot arm. A power cord extends from the robot arm 33 to the heater.
1 has a structure in which a wiring 39, a temperature sensor 41, and a heating element 43 are accommodated in a stainless steel cylinder 37 having an axial length of about 5 cm and an outer diameter of about 5 mm. Have. The heating element 43 is disposed at the tip of the heater unit 35. The temperature sensor 41 is arranged at a position away from the heating element by a predetermined distance (for example, 1 cm), and temperature data for controlling energization to the heating element so that the temperature at the tip of the iron tip described later becomes an appropriate working temperature. Is transmitted to a computer (not shown) that manages the soldering operation. Also, a cap nut 45 for removably attaching a lead-free soldering iron tip of the present invention, which will be described later, is fastened near the attachment portion of the heater portion 35 to the robot arm 33. The tip 10 is attached / removed by loosening the cap nut 45 by rotating it counterclockwise, and the end portion of the tip 10 inserted into the cap nut is tightened by rotating the cap nut clockwise to the heater unit 35. Fixed.

A specific example of the lead-free soldering iron tip 10 of the present invention used by being attached to the soldering iron body 31 described above will be described below with reference to FIGS. 1 and 2. FIG. 2 is a sectional view of the lead-free soldering iron tip according to the present embodiment, in which the portion surrounded by a round frame in FIG. 1 is partially cut in the axial direction.
The lead-free soldering iron tip 10 is composed of a barrel portion 51 inserted into the heater portion 35 described above, and a base 12 having a tip attached to the tip of the barrel portion and having a pen point shape. The cartridge structure is used by being attached to the heater portion 35 of the cartridge.

  The body portion 51 has a thin cylindrical shape with an inner diameter of about 6 mm and an axial length of about 4 cm, and a metal having a low thermal conductivity, such as stainless steel, is used as the material thereof. The body part 51 is fitted on the outer periphery of the round bar-shaped heater part 35, and at the same time as the front end of the heater part reaches the deepest part, the body end part (rear end) is inserted into the cap nut 45 to rotate the cap nut clockwise. It is fixed to this.

  The base body 12 attached to the tip of the body part 51 is a solid columnar base part 53 having a length of about 3 cm having a thickness (outer diameter is less than 7 mm) that can be fitted into the cylindrical body part, The outer shape is composed of a nib-shaped tip portion 55 having a length of about 2 cm that decreases in diameter toward the tip. The base part 53 is inserted into the body part 51 up to about half of its length, and the base part is the thickness of the body part so that no step is generated when the base part is inserted into the body part. Only the diameter is reduced. In this embodiment, the tip portion 55 has a pen tip shape, but is not limited to this, and it is needless to say that various shapes that are optimal for soldering can be used according to the application.

Oxygen-free copper is used as the material of the base 12, and an iron plating 14 is applied to the entire surface as a base plating with a film thickness of 200 μm to 1500 μm. This iron plating 14 is intended to improve the wettability with the solder, and by ensuring a predetermined uniform film thickness, the product has a long life and good heat release.
Further, the base 12 on which the iron plating 14 is applied has a contact surface P with the solder in a range of about 4 mm at the tip of the tip. On the surface of the iron plating layer 14 excluding the contact surface P, a hard chrome plating layer 16 and a black chrome plating layer 18 are formed so as to overlap therewith. The film thicknesses of the hard chrome plating layer 16 and the black chrome plating layer 18 are about 5 μm to 20 μm in total. This hard chrome plating 16 is intended to increase wear resistance and corrosion resistance against the flux contained in the solder, etc., but in the region of about 350 ° C., which is the working temperature of lead-free solder, the corrosion resistance of the hard chrome plating. Since the chemical resistance is low, a black chrome plating layer 18 is formed on top of this. The black chrome plating 18 has low wettability (high solder repellent property) and higher corrosion and chemical resistance to prevent corrosion and to prevent the solder from rising, ensuring the accuracy of soldering work by industrial robots. By ensuring the uniformity, it is possible to further secure the cost, and at the same time, the consumption of the iron tip can be greatly reduced to reduce the total cost in the production line.

Further, the solder tip 24 and a non-heat-resistant resin 24 are attached to the contact surface P on the tip of the iron tip on which the iron plating 14 is applied so as to cover the spare solder. The spare solder 22 prevents the iron plating 14 on the contact surface P from being exposed and oxidized, and improves the familiarity between the solder and the tip contact surface P at the beginning of the use of the solder tip 10. Is. As the non-heat resistant resin 24, for example, polyvinyl chloride is used. This resin protects the spare solder 22 and functions as a mask for preventing the plating layer from being formed on this portion when the iron tip 10 is manufactured.
In addition, since this resin is cracked and peeled off by preheating to use the iron tip 10 for the first time, the iron tip is used after further sufficient (preliminary) soldering is performed on the resin with solder. .

  Next, a method for manufacturing the lead-free soldering iron tip 10 of the present invention will be described. FIG. 3 is a flowchart showing the manufacturing process of the tip of the present invention.

[Material processing]
First, the base material 12 is manufactured by processing the cylindrical oxygen-free copper in a dimension that takes into consideration the plating thickness by the plating process to be performed later, and the surface is polished for the iron plating process to be performed next.

[Iron plating treatment]
An iron plating layer 14 is formed on the pretreated substrate 12. In order to ensure a film thickness above a certain level and eliminate variations in plating thickness, the plating process is performed over a long period of about 23 hours using a constant voltage automatic rectifier that performs a soft start by increasing the current value steplessly. I do. If the current value is increased stepwise by a manual rectifier and a film thickness of a certain level or more is secured, there is a risk that peeling of the iron plating layer or poor solder wettability may occur at the point where the current value has changed.

[Finishing]
The base 12 subjected to the iron plating process is finished according to the final finish dimension while considering that the tip plating thickness is 200 μm to 1500 μm.

[Preliminary soldering and masking]
The most advanced portion of the substrate 12 that has been subjected to finishing processing is subjected to mechanical polishing and chemical polishing, and then subjected to soldering treatment with a highly active flux, so that preliminary solder 22 is deposited on the iron plating 14 layer. Further, the most advanced portion of the substrate 12 is masked with polyvinyl chloride to protect the shape and prepare for later chromium plating.

[Hard chrome plating]
In addition to the solder contact surface P, hard chromium plating 16 having excellent wear resistance and corrosion resistance and having no solder wettability is applied to prevent the solder from rising.

[Black chrome plating]
In order to more reliably prevent the solder from rising, a black chrome plating 18 having a higher corrosion resistance to the flux than the hard chrome plating 16 is applied to the hard chrome plating layer 16 in addition to the solder contact surface P.

[Body attachment]
A base body that has been subjected to various plating processes is fitted into a cylindrical body 51 to complete an attached product.

  According to the iron tip for lead-free solder of the present invention described above, it is possible to effectively prevent the phenomenon that the solder rises in addition to the leading edge of the iron tip. The soldering work can be performed so that the optimal amount of solder is placed only on the soldering iron), ensuring the accuracy of soldering work, especially low-temperature soldering work using lead-free solder by industrial robots It becomes possible to do. In addition, since the durability of the soldering tip with respect to the flux can be further increased, the cost of soldering can be reduced.

It is the perspective view which showed the soldering iron main body and the tip for lead-free soldering of this invention used by being attached to this. FIG. 2 is a cross-sectional perspective view in a state where a portion surrounded by a round frame in FIG. 1 is partially cut in the axial direction in order to explain the structure of the lead-free soldering iron tip of the present embodiment. It is the flowchart which showed the manufacturing process of the iron tip of this invention.

Explanation of symbols

P Solder contact surface 10 Tip 12 Base 14 Iron plating layer 16 Hard chrome plating layer 18 Black chrome plating layer 22 Preliminary solder 24 Non-heat resistant resin 31 Soldering iron body 33 Robot arm 35 Heater part 37 Cylinder 39 Wiring 41 Temperature sensor 43 Heating element 45 Cap nut 51 Trunk part 53 Base part 55 Tip part

Claims (6)

  The surface of the iron plating layer excluding the contact surface (P) between the pure iron plating layer or iron nickel alloy plating layer (14) applied as the base plating on the entire surface of the base (12) of the iron tip (10) and the solder A lead-free soldering iron tip having a hard chrome plating layer (16) applied to the surface and a black chrome plating layer (18) applied thereon.   The preliminary solder (22) and a non-heat resistant resin (24) are deposited on the iron plating layer (14) of the solder contact surface (P) portion so as to cover the preliminary solder. The tip for lead-free solder described in 1.   The tip for lead-free solder according to claim 1, wherein the base body is made of oxygen-free copper.   4. The lead-free soldering iron tip according to claim 1, wherein the iron plating layer has a thickness of 200 μm to 1500 μm. 5.   Iron plating (14) is applied to the entire surface of the base (12) of the iron tip (10) as a base plating, and the hard chrome plating (16) is overlaid on the surface of the iron plating layer excluding the contact surface (P) with the solder. A method of manufacturing a lead-free soldering iron tip, characterized by being subjected to black chrome plating (18).   Preliminary solder (22) was deposited on the solder contact surface (P) of the base (12) subjected to iron plating (14), and non-heat resistant resin (24) covering the spare solder was deposited thereon. 6. The method for producing a lead-free soldering iron tip according to claim 5, wherein: