CN106825812A - A kind of ameliorative way of convex surface silver contact resistance brazing - Google Patents

Abstract

The invention relates to the field of welding technology and aims to provide an improved method for resistance brazing of convex silver contacts. Including: processing the end face of the electrode head used for silver contact resistance brazing into a concave spherical surface; opening several notches in the center of the end face of the electrode head; performing flat milling on the outer boundary of the electrode concave spherical surface; The notch boundary and arc surface boundary are deburred; the end face of the electrode tip is pressed against the convex silver contact assembly, and then resistance brazing is performed. The invention creatively introduces the notch into the welding electrode of resistance brazing, and can obtain a silver contact assembly with a good convex surface after welding; reduces the falling off of the silver contact after welding, and the deviation of the welding position of the silver contact, and improves the silver contact assembly of the convex surface. The qualification rate of spot welding components has significantly improved production efficiency. It is simple and easy to process, easy to realize large-scale production and application, and has significant economic benefits.

Description

An improved method for resistance brazing of convex silver contacts

technical field

The invention belongs to the field of welding technology, and in particular relates to an improved method for resistance brazing of convex silver contacts.

Background technique

Silver contact assemblies are the core components of various circuit breakers in the field of low-voltage electrical appliances. When silver contacts are used, they are often required to be integrated with copper (or copper alloy) with better conductivity. The connection methods of silver contacts include resistance brazing, induction brazing, and overall liquid phase sintering. Resistance brazing is to apply pressure to the components to be welded separately through the welding electrodes, and rely on the resistance heat generated by the current passing through the components to be welded to heat the components to be welded and melt the solder to achieve metal connection.

Welding with conventional resistance brazing methods, such as welding with electrodes with a flat cross section, or welding with concave electrodes that completely match the spherical contacts, will easily cause the convex surface of the silver contact to be flattened, and the convex silver contact is easy to stick If it is stuck in the concave electrode and cannot be taken out, it is easy to open and fall off after welding.

The literature "On the Selection of Electrode Materials for Resistance Welding of Contact Components and the Design of Welding Process in Special Cases" adopts the method of designing the electrode section as convex ribs to resistance weld the spherical silver contacts, but this method cannot fix the silver contacts well, and the silver contacts The point can move in the direction parallel to the convex rib, which is easy to cause the displacement of the convex silver contact; and the contact area between the convex rib electrode and the silver contact is too small, and the temperature is prone to be too high during welding, and the distribution of the nugget is biased towards the convex rib The contact surface with the silver contact, welding residual stress and other problems, to a certain extent, affect the welding strength of the convex silver contact assembly after welding.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the deficiencies and defects of the prior art and provide an improved method for resistance brazing of convex silver contacts.

In order to solve technical problems, the present invention is achieved through the following technical solutions:

An improved method for resistive brazing of convex silver contacts is provided, comprising the steps of:

(1) Process the end face of the electrode head used for silver contact resistance brazing into a concave spherical surface;

(2) Make several notches in the center of the end face of the electrode head;

(3) Carry out flat milling to the outer boundary of the concave spherical surface of the electrode;

(4) Deburring the notch boundary and the arc surface boundary;

(5) Press the end face of the electrode tip against the convex silver contact assembly, and then perform resistance brazing.

In the present invention, the processing of the end surface of the electrode head into a concave spherical surface is realized by machining with a milling cutter or CNC machine tool.

In the present invention, the concave spherical surface has the same curvature as the convex surface of the silver contact.

In the present invention, the slotting at the center of the end face of the electrode head is realized by means of milling cutter or wire cutting.

In the present invention, the shape of the notch at the center of the end face of the electrode tip is cross-shaped, three-lobed rotating, or star-shaped; the depth of the notch is 0.1mm-3mm, and the width is 10%-40% of the diameter of the silver contact.

In the present invention, the flat milling treatment refers to that the outer boundary of the end face of the electrode head is carried out with a flat milling cutter, so that the width of the contact area between the electrode and the silver contact is 5% of the diameter of the silver contact after the flat milling ~30%.

In the present invention, during the flat milling process, the milling cutter is installed parallel to the central axis of the electrode, and moves along a plane perpendicular to the central axis.

In the present invention, during the flat milling process, the depth of the flat milling is the same as or different from the depth of the notch, and its depth dimension does not exceed the height of the convex surface of the silver contact.

After the first four steps of processing, the concave spherical surface of the electrode is pressed against the convex surface of the silver contact, and then pressure is applied to the top of the electrode to compress the silver contact and the copper contact bridge. Based on the idea of protecting the top of the convex surface of the silver contact, the center of the electrode cross-section is slotted, so the top of the convex surface of the silver contact does not contact the cross-section of the electrode to avoid flattening of the convex surface of the silver contact and avoid the top of the convex surface of the silver contact Adhesive to electrodes.

Description of invention principle:

The method for improving the resistance brazing of the convex silver contact of the present invention is different from the existing ones in that electrodes with concave end faces and slots in the center are selected for resistance brazing. The design of the welding electrode of the present invention makes it difficult for the convex silver contact to be displaced, the convex surface is not easy to be damaged after welding, and it is not easy to open and fall off after welding, which can better meet the requirements of different conditions.

Compared with the prior art, the present invention has the beneficial effects:

(1) The invention creatively introduces the notch into the resistance brazing welding electrode, which can obtain a silver contact assembly with a good convex surface after welding;

(2) Compared with the traditional convex silver contact resistance brazing, the present invention reduces the situation that the silver contact falls off after welding and the silver contact welding position shifts, improves the qualification rate of the convex silver contact welding assembly, and significantly improves production efficiency.

(3) It is simple and easy to process in terms of technology, easy to realize large-scale production and application, and has significant economic benefits.

The present invention fully considers the influence of multi-objective factors in the welding process of the convex silver contact, and solves the problem that the convex surface of the prior art is difficult to weld, the top of the convex surface of the silver contact is easy to stick to the electrode, the silver contact is easy to shift, and the convex surface is flattened after welding. , After welding, it is easy to open and weld off.

Description of drawings

Among Fig. 1 (a) is the schematic diagram of convex silver contact resistance brazing of the embodiment of the present invention 1, (b) is the schematic diagram of the upper electrode end face of the embodiment of the present invention 1;

In the figure: 101-upper electrode, 102-convex silver contact, 103-copper contact bridge, 104-copper tungsten base, 105-lower electrode, 106-concave spherical surface of electrode end face, 107-cross shape of electrode head Groove, the intersection center of this groove is square;

Among Fig. 2, (c) is a schematic diagram of convex silver contact resistance brazing in Embodiment 2 of the present invention, and (d) is a schematic diagram of an upper electrode end face in Embodiment 2 of the present invention;

In the figure: 201-upper electrode, 202-convex silver contact, 203-copper contact bridge, 204-copper tungsten base, 205-lower electrode, 206-concave spherical surface of electrode end face, 207-cross shape of electrode head Groove, the cross center of this groove is circular;

Among Fig. 3, (e) is the schematic diagram of convex silver contact resistance brazing of the embodiment of the present invention 3, and (f) is the schematic diagram of the upper electrode end face of the embodiment of the present invention 3;

In the figure: 301-upper electrode, 302-convex silver contact, 303-copper contact bridge, 304-copper tungsten base, 305-lower electrode, 306-concave spherical surface of electrode end face, 307-three leaves of electrode head Rotary groove, the intersection center of this groove is circular;

(g) in Fig. 4 is a schematic diagram of resistance brazing of a convex silver contact in Example 4 of the present invention, and (h) is a schematic diagram of an end surface of an upper electrode in Example 4 of the present invention.

In the figure: 401-upper electrode, 402-convex silver contact, 403-copper contact bridge, 404-copper tungsten base, 405-lower electrode, 406-concave spherical surface of electrode end face, 407-star shape of electrode head A groove with a star-shaped center of intersection for this groove.

detailed description

The following examples of the present invention are described in detail, and the following examples provide detailed implementation methods and specific operation processes, but the protection scope of the present invention is not limited to the following examples.

Example 1

As shown in Figure 1, the resistance brazing process of a certain type of convex surface silver contact is improved by adopting the method of the present invention, and the method comprises the following steps:

In the first step, the end surface of the electrode head 101 used for silver contact resistance brazing is machined by a numerically controlled lathe to make it a concave spherical surface 106 . The curvature of the concave spherical surface 106 is consistent with the curvature of the convex surface of the silver contact 102 to be soldered, and the radius of curvature of the convex surface is 15 mm.

In the second step, a cross-shaped notch 107 is cut in the center of the electrode end surface processed in the first step by wire cutting, the depth of the notch is 1 mm, and the width of the notch is 34.2% of the diameter of the silver contact 102 .

The 3rd step, carry out flat milling to the outer boundary of the end face of the electrode head 101 processed through the first step and the second step by the flat milling cutter, so that the width of the contact area of the electrode 101 tip and the silver contact 102 after the flat milling is silver 30% of the contact 102 diameter. The flat milling refers to that the milling cutter is parallel to the central axis of the electrode and moves along a plane perpendicular to the central axis. The flat milling depth is different from the notch 107 depth.

The fourth step is to deburr the boundary of the notch 107 and the boundary of the spherical surface 106 .

In the fifth step, use the electrode 101 processed through the first step to the fourth step to carry out the resistance brazing of the convex silver contact 102, wherein, the concave spherical surface 106 of the electrode is close to the convex surface of the silver contact 102, and then on the top of the electrode Press 101 to compress the silver contact 102 and the copper contact bridge 103, and then perform resistance brazing to complete the improvement process of resistance brazing of the convex silver contact 102.

Compared with the traditional resistance brazing method of convex silver contacts, the improved brazing method can optimize the nugget distribution. For the same batch of convex silver contacts, the number of silver contacts with high shear strength after welding increases significantly, while The top of the convex surface of the silver contact sticks to the electrode, the silver contact is displaced, and the convex surface is crushed.

Example 2

As shown in Figure 2, the method of the present invention is used to improve the resistance brazing process of a certain type of convex silver contact. The difference from Embodiment 1 is that the depth of the notch 207 is adjusted to 0.1 mm, and the width of the notch 207 is adjusted to 0.1 mm. Adjusted to 25% of the diameter of the silver contact, the shape of the center of the notch 207 is adjusted from a square to a circle, and the width of the contact area between the electrode tip 201 and the silver contact 202 is adjusted to 11.7% of the diameter of the silver contact 202. A chamfering treatment with a size of 2 mm is added to the outer boundary of the electrode end face, and the method includes the following steps:

In the first step, the end surface of the electrode head 201 used for silver contact resistance brazing is machined by CNC machine tool to make it into a concave spherical surface 206 . The curvature of the concave spherical surface 206 is consistent with the curvature of the convex surface of the silver contact 202 to be soldered, and the radius of curvature of the convex surface is 75mm.

In the second step, a cross-shaped notch 207 is made in the center of the electrode end face processed in the first step by milling with a milling cutter. The depth of the notch is 0.1 mm, and the width of the notch is 25% of the diameter of the silver contact 202. A circular groove with a diameter of 7 mm is rotary milled at the center intersection of the mouth 207, and the depth of the circular groove is also 0.1 mm.

In the third step, the outer boundary of the electrode head 201 end face processed through the first step and the second step is carried out by a flat milling cutter, so that the width of the contact area between the electrode tip 201 and the silver contact 202 after the flat milling is 2. 11.7% of the contact 202 diameter. The flat milling refers to that the milling cutter is parallel to the central axis of the electrode and moves along a plane perpendicular to the central axis. The flat milling depth is different from the notch 207 depth. In addition, the outer boundary of the end surface of the electrode 201 is chamfered, and the distance to the end point is 2 mm.

The fourth step is to deburr the boundary of the notch 207 and the boundary of the spherical surface 206 .

In the fifth step, use the electrode 201 processed through the first step to the fourth step to carry out the resistance brazing of the convex surface silver contact 202, wherein the concave spherical surface 206 of the electrode is close to the convex surface of the silver contact 202, and then on the top of the electrode 201 is pressurized, thereby pressing the silver contact 202 and the copper contact bridge 203, and then resistance brazing is performed to complete the improvement process of resistance brazing of the convex silver contact 202.

Compared with the traditional resistance brazing method of convex silver contacts, the improved brazing method can optimize the nugget distribution. For the same batch of convex silver contacts, the number of silver contacts with high shear strength after welding increases significantly, while The top of the convex surface of the silver contact is sticking to the electrode, the silver contact is displaced, and the convex surface is crushed, which is significantly reduced, and the product qualification rate has increased by 21.5%.

Example 3

As shown in Figure 3, the resistance brazing process of a certain type of convex silver contact is improved by adopting the method of the present invention. The depth of 307 is adjusted to 3mm, the width of notch 307 is adjusted to 10% of the diameter of the silver contact 302, the width of the contact area between the electrode tip 301 and the silver contact 302 is 16.8% of the diameter of the silver contact 302, and the flat milling depth is the same as the groove Ports 307 are the same depth. The method comprises the steps of:

In the first step, the end face of the electrode head 301 used for silver contact resistance brazing is milled into a concave spherical surface 306 by milling with the milling cutter track method. The curvature of the concave spherical surface 306 is consistent with the curvature of the convex surface of the silver contact 302 to be soldered, and the radius of curvature of the convex surface is 35 mm.

In the second step, a three-lobed rotary shape is cut in the center of the end face of the electrode 301 processed in the first step by milling, the depth of the notch is 3 mm, and the width of the notch is 10% of the diameter of the silver contact 302 .

The 3rd step, carry out flat milling to the outer boundary of the end face of the electrode head 301 processed through the first step and the second step by the flat milling cutter, so that the width of the contact area between the electrode tip 301 and the silver contact 302 after the flat milling is silver 16.8% of the contact 302 diameter. The flat milling refers to that the milling cutter is parallel to the central axis of the electrode and moves along a plane perpendicular to the central axis. The flat milling depth is the same as the notch 307 depth.

The fourth step is to deburr the boundary of the notch 307 and the boundary of the spherical surface 306 .

In the fifth step, use the electrode 301 processed through the first step to the fourth step to carry out convex silver contact resistance brazing, wherein the concave spherical surface 306 of the electrode is close to the convex surface of the silver contact 302, and then on the top of the electrode 301 Apply pressure to compress the silver contact 302 and the copper contact bridge 303, and then perform resistance brazing to complete the improvement process of convex silver contact resistance brazing.

Compared with the traditional resistance brazing method of convex silver contacts, the improved brazing method can optimize the nugget distribution. For the same batch of convex silver contacts, the number of silver contacts with high shear strength after welding increases significantly, while The top of the convex surface of the silver contact sticks to the electrode, the silver contact is displaced, and the convex surface is crushed, which is significantly reduced, and the product qualification rate has increased by 16.6%.

Example 4

As shown in Figure 4, the method of the present invention is used to improve the resistance brazing process of a certain type of convex silver contact. The difference from Embodiment 1 is that the shape of the notch 407 is star-shaped, and the depth of the notch 407 is adjusted. The width of the notch 407 is adjusted to be 40% of the diameter of the silver contact 402, and the width of the contact area between the electrode tip 401 and the silver contact 402 is 5% of the diameter of the silver contact 402. The method comprises the steps of:

In the first step, the end surface of the electrode head 401 used for silver contact resistance brazing is machined by a numerically controlled lathe to make it a concave spherical surface 406 . The curvature of the concave spherical surface 406 is consistent with the curvature of the convex surface of the silver contact 402 to be soldered, and the radius of curvature of the convex surface is 25mm.

In the second step, a star-shaped notch 407 is cut in the center of the electrode end face processed in the first step by wire cutting, the depth of the notch is 1.5 mm, and the width of the notch is 40% of the diameter of the silver contact 402 .

The 3rd step, carry out flat milling process through the outer boundary of the electrode head 401 end faces processed in the first step and the second step by flat milling cutter, make the width of the contact area of electrode 401 tip and silver contact 402 after flat milling be silver 5% of the contact 402 diameter. The flat milling refers to that the milling cutter is parallel to the central axis of the electrode and moves along a plane perpendicular to the central axis. The flat milling depth is different from the notch 407 depth.

The fourth step is to deburr the boundary of the notch 407 and the boundary of the spherical surface 406 .

In the fifth step, use the electrode 401 processed through the first step to the fourth step to carry out the resistance brazing of the convex silver contact 402, wherein the concave spherical surface 406 of the electrode is close to the convex surface of the silver contact 402, and then on the top of the electrode Press 401 to compress the silver contact 402 and the copper contact bridge 403 , and then perform resistance brazing to complete the improvement process of resistance brazing of the convex silver contact 402 .

Compared with the traditional resistance brazing method of convex silver contacts, the improved brazing method can optimize the nugget distribution. For the same batch of convex silver contacts, the number of silver contacts with high shear strength after welding increases significantly, while The top of the convex surface of the silver contact sticks to the electrode, the silver contact is displaced, and the convex surface is crushed, which is significantly reduced, and the product qualification rate has increased by 19%.

It should be understood that the parameters involved in the above embodiments can be adjusted within the scope of the present invention, for example, the width of the notch can be arbitrarily selected from 10% to 40% of the diameter of the silver contact; , can be realized by milling with a milling cutter or CNC machine tool, or by other methods in the prior art; in addition, the shape of the notch can be cross-shaped, three-lobed rotary, star-shaped or other shapes, and it is not limited The records in the above-mentioned embodiments; this can be easily realized by those skilled in the art on the basis of the records in the description of the present invention, so it will not be repeated here.

The above descriptions are only part of the embodiments of the present invention, and are not intended to limit the technical scope of the present invention. Any modifications made within the spirit and principles of the present invention, equivalent replacements and improvements, etc., should be included in the present invention. within the scope of protection.

Claims (8)

1. a kind of ameliorative way of convex surface silver contact resistance brazing, it is characterised in that comprise the following steps：

(1) end face of silver contact resistance brazing electrode used therein head is processed into the Surface of Sphere of indent；

(2) end face center in electrode tip outputs several notch；

(3) external boundary to electrode indent Surface of Sphere carries out plain milling treatment；

(4) deburring treatment is carried out to notch border and cambered surface border；

(5) end face of electrode tip is compressed into convex surface silver contact component, then carries out resistance brazing.

2. method according to claim 1, it is characterised in that the ball that the end face of electrode tip is processed into indent Face, is to process to be machined and realized by milling tool or Digit Control Machine Tool.

3. method according to claim 1, it is characterised in that the Surface of Sphere of indent has identical bent with silver contact convex surface Rate.

4. method according to claim 1, it is characterised in that slotted in the end face center of electrode tip, be by milling cutter or What the mode of wire cutting was realized.

5. method according to claim 1, it is characterised in that the shape of the notch of the electrode tip end face center is cross Type, three leaves are rotary-type, star-like；The depth of notch is 0.1mm~3mm, and width is the 10%~40% of silver contact diameter.

6. method according to claim 1, it is characterised in that the plain milling treatment, refers to electrode head end with plain cutter The external boundary in face carries out plain milling treatment so that electrode and the width of the contact area of silver contact are silver contact diameter after plain milling 5%~30%.

7. method according to claim 1, it is characterised in that when the plain milling is processed, milling cutter is parallel to electrode axis Install, and plane motion is done along the plane perpendicular to axis.

8. method according to claim 1, it is characterised in that when the plain milling is processed, plain milling depth and depth of rebate phase Same or different, its depth dimensions is no more than silver contact convex surface highly.