CN1004681B

CN1004681B - Bridge wire laser welding method

Info

Publication number: CN1004681B
Application number: CN85107767.6A
Authority: CN
Inventors: 李永正; 张秋鄂; 马书林; 郝万吉; 吕德隆
Original assignee: Changchun Institute of Optics Fine Mechanics and Physics of CAS
Current assignee: Changchun Institute of Optics Fine Mechanics and Physics of CAS
Priority date: 1985-10-15
Filing date: 1985-10-15
Publication date: 1989-07-05
Also published as: CN85107767A

Abstract

The invention provides a bridge wire laser welding method, which aims to solve the problem of welding a bridge wire and a lead wire of a military initiating explosive device. The present invention features that laser bridge wire welding is used and metal material except two mutually welded parts of bridge wire and lead wire is used in the welding spot. Such metallic materials are used as interposers and cladding layers in laser welding. In some cases, only an interposer or a cap layer may be used. The method has wide applicability in bridge wire welding of military initiating explosive devices. The bridge wire laser welding of various leads such as copper, brass and the like is realized. The invention is also applicable 10^-2Laser welding of mm-grade filaments, sheets and guide materials.

Description

Laser welding method for bridge wire

The invention relates to a bridge wire laser welding method in the technical field of laser processing.

For the welding between the bridge wire and the lead wire of the military initiating explosive device, soldering iron is mostly adopted at present. The welding has the problems that the welding spot quality is unstable and the like because the mutual welding pieces are not mutually fused.

In order to solve the problem, the invention adopts a bridge wire laser welding method. However, in laser welding, due to the thin bridge wire and the high thermal conductivity of the copper lead material, the reflection coefficient is large, the boiling point of the brass lead is low, good welding is difficult to form, and the wire breakage phenomenon often occurs. In addition, in the laser welding process, the strength of the welding spot is influenced due to the thinning of the bridge wire.

The invention aims to provide an effective bridge wire laser welding method, which not only realizes reliable laser mutual fusion welding of ultra-thin bridge wires such as nickel-chromium, platinum-iridium and the like and various leads including copper and brass leads with greatly different sizes and properties, but also improves the quality of welding spots and effectively solves the wire breakage phenomenon easily occurring in the welding.

The invention is realized by the following steps: and welding by adopting pulse laser energy. One or two metallic materials other than the two mutual weldments of the bridgewire and the lead are used at the laser welding point. An intermediate material different from the lead wire is welded on the end face of the lead wire by laser, so that the property of the material directly contacting with the bridge wire is changed, and for the lead wire such as copper, the heat conductivity and the reflectivity can be reduced. Adverse effects on the welding due to the low boiling point of zinc are avoided for brass leads. Direct weldability of the bridgewire to the lead wire can be structurally solved for some lead wire materials. Then, a metal material which is the same as or different from the intermediate material is covered on the bridge wire which is in contact with the intermediate material, and welding is performed by using a pulse laser. The bridge wire is protected by the covering layer, and reliable and smooth welding spots can be formed. When the lead wire used has good weldability, such as a lead wire made of stainless steel or iron, the lead wire can be welded by using only the covering layer without using an intervening material. When the use of a bridging filament is not too thin and a high quality solder joint is not required, the welding can be performed with only the intermediary material and without the covering material. The intermediate material and the cover layer may be the same material or different materials. The intermediate material or coating may be the same material as the bridge wire to which it is welded or may be a different material. The intermediary material and the cladding material may be pure metals, alloys, self-fluxing alloys, composite materials, and flux-containing materials as are commonly used for welding. The materials of the intermediate layer and the covering layer can be powder, sheet, silk and hemisphere. During laser welding, the bridge wire, the lead wire and the additional material are mutually fused and are metallurgically bonded.

The method solves the problem of laser welding of 0.01 mm-order bridgewire starting from 0.01mm and 0.5mm or thicker lead wire. The bridge wire may be nickel chromium, platinum iridium, tungsten, etc. The lead wire may be iron, nickel, stainless steel, copper, brass, copper core soft magnetic material clad composite wire, kovar, etc. The welding spot welded by the method has good quality stability, high welding yield and small correlation with the specific material types of the lead and the bridge wire. Is a commonly applicable method for bridge wire laser welding. The invention can also be used for laser welding of filaments and special-shaped materials with large size difference and performance difference. The filaments can be various common filaments with the size of 0.01mm from 0.01mm, and the special-shaped pieces welded with the filaments can be made of copper, aluminum, copper alloy, cast steel, iron, nickel, kovar and the like. The invention also realizes the laser welding of the extremely thin metal sheet and the special-shaped material. If the metal powder is adopted for covering, the micro-rivet effect can be obtained at the welding spot, and the strength of the welding spot is increased.

Examples of the invention are as follows: laser welding of the nickel-chromium bridge wire (phi 0.02 m) and the copper lead wire (phi 0.5 mm) of the electric detonator. Laser pulse spot welding is adopted, nickel-chromium-boron-silicon self-fluxing alloy powder is put into the spot welding to be used as an intermediate layer and a covering layer. The method comprises the steps of firstly using a 0.2mm blade as a powder thickness measuring plate, using a scraper to leave a 0.2mm nickel-chromium-boron-silicon powder layer on the upper edge of the end of a lead, using a YAG pulse laser and welding with 0.5 joule pulse energy to enable powder to be welded on the end of a copper lead to form an intermediate layer, laying a powder layer of the same material with the thickness of 0.2mm by the same method after a bridge wire is laid, and then using 0.2 joule pulse laser to weld to form a welding point.

Claims

1. A laser welding method for bridge wire features that the laser energy is used to fuse the bridge wire and leading wire to form a welding spot, and the covering material and/or intermediate material are used at the welding spot.

2. The method of claim 1 wherein the cladding material and the intermediate material are nickel-based, nickel-chromium-based, iron-based, copper-based, cobalt-based self-fluxing alloys or alloys containing flux such as nickel, iron, copper, stainless steel, kovar.

3. The bridgewire laser welding method of claim 1 wherein the cladding material and the intermediate material are in the form of powder, flakes, spheres, or filaments.

4. The method of claim 1, wherein the material of the bridge wire is selected from the group consisting of nickel-chromium wire, platinum-iridium wire, and tungsten wire.

5. The method of claim 1 wherein the lead material used is copper, brass, aluminum, iron, nickel, stainless steel or kovar.