CN111243802B

CN111243802B - Leadless resistor with auxiliary lead and welding method

Info

Publication number: CN111243802B
Application number: CN202010042647.6A
Authority: CN
Inventors: 钟鹏辉
Original assignee: Dongguan Kailirui Intelligent Technology Co ltd
Current assignee: Dongguan Kailirui Intelligent Technology Co ltd
Priority date: 2020-01-15
Filing date: 2020-01-15
Publication date: 2022-09-13
Anticipated expiration: 2040-01-15
Also published as: CN111243802A

Abstract

The invention relates to a leadless resistor with auxiliary leads, which comprises a leadless resistor, wherein the two ends of the leadless resistor are provided with the auxiliary leads, the surface of a cap of the leadless resistor is in spot welding with the auxiliary leads, and after the auxiliary leads are cut off, the area of a crater formed on the surface of the cap is the cross section area of the auxiliary leads. The leadless resistor plays a role in limiting current and reducing voltage of a circuit to fuse a fuse element, an auxiliary lead needs to be welded in the manufacturing process of the leadless resistor to assist subsequent manufacturing procedures such as paint coating, color code marking and the like, and the auxiliary lead is cut (the auxiliary lead is cut) after the procedures are completed. The invention realizes point connection of the lead and the cap, ensures the quality of dissimilar metal connection, and solves the problem that the quality of the leadless resistor is influenced by cutting the cap due to pin cutting.

Description

Leadless resistor with auxiliary lead and welding method

Technical Field

The invention relates to a method for manufacturing a leadless resistor, in particular to a leadless resistor with an auxiliary lead, a welding tool method and a leadless resistor manufacturing process.

Background

Leadless cylindrical resistors are used in a large number of applications in the electronics industry. The leadless resistor can be pasted to carry out circuit pasting, so that the demand of the leadless resistor is higher and higher. The current methods for manufacturing the leadless resistor include the following steps:

one, no lead film type resistor (with lead paint)

The technology comprises the steps of coating a film magnetic rod cap, cutting resistance, welding a cut body cap with the resistance with a lead, fixing the lead through equipment, painting paint, printing color codes and printing words, and then cutting a pin (namely cutting the just welded lead).

Two, no lead wire winding resistor (with lead wire painting)

The method comprises the steps of firstly covering a white rod with a cap, winding (winding a nickel-chromium wire, a manganese-copper wire and a constantan wire on the white rod), then welding the wound body cap with a resistance value with a lead, then painting and coating color codes and printing characters, and then cutting feet.

No matter no lead film type resistor or no lead wire winding resistor, the no lead wire resistor can be effectively and suitably manufactured in a production line mode only by welding auxiliary leads at two ends of the resistor to assist subsequent manufacturing procedures such as painting, color code marking and the like in the manufacturing process, and then cutting pins (cutting off the auxiliary leads) after the procedures are completed, after the auxiliary lead and the cap are welded by the prior art, the welding point of the auxiliary lead and the cap is in a planar structure, as shown in figure 2, the craters formed on the surface of the cap after the feet are cut off after painting, as shown in fig. 3, result in a large tensile shear load between the auxiliary leads and the cap, so that the cap is easy to be damaged when the pin needs to be cut (the auxiliary lead is cut) after the resistor is painted, the quality of the leadless resistor is influenced, and secondly, the craters formed on the surfaces of the caps at the two ends of the leadless resistor are large, so that the leadless resistor is not easy to cut off and the quality and the appearance of the leadless resistor are influenced.

Disclosure of Invention

In order to solve the problems, the invention provides a leadless resistor with an auxiliary lead and a welding tool method.

In order to realize the purpose, the invention adopts the following technical scheme: the utility model provides a no lead wire resistance with supplementary lead wire, includes no lead wire resistance, no lead wire resistance both ends be equipped with supplementary lead wire, no lead wire resistance include the resistance body and locate resistance body both ends cap, cap surface and supplementary lead wire between form the nugget through spot welding, the nugget area slightly equals supplementary lead wire cross-sectional area.

Preferably, after the auxiliary lead is cut off, the area of the crater formed on the surface of the cap is the cross-sectional area of the auxiliary lead.

A welding method of a leadless resistor with an auxiliary lead comprises the following steps:

the method comprises the following steps: electrically connecting the cap with a first electrode, wherein the first electrode is connected with a welding power supply;

step two: electrically connecting the auxiliary lead with a second electrode, wherein the second electrode is connected with a welding power supply;

step three: approaching: the auxiliary lead is close to the surface of the cap, the closing time is T1ms, no discharge occurs in the closing process, and discharge begins when the auxiliary lead is in contact with the cap;

step four: and (3) welding, namely forming a welding loop by the first electrode, the second electrode, the cap and the lead after the auxiliary lead is contacted with the cap, and completing welding to separate the second electrode from the lead after discharging for a plurality of times by a welding power supply to obtain the welded leadless resistor with the auxiliary lead.

Preferably, after step three, the auxiliary lead is contacted with the cap and pressed for a pre-pressing time, the pre-pressing time is T2ms, and the pressure applied to the auxiliary lead on the surface of the cap during the pre-pressing process is FKg.

Preferably, after welding, discharging is stopped, and the welding power supply is controlled to perform pressure holding for a pressure holding time T10 ms.

Preferably, in the fifth step, the plurality of discharges have three discharge states, and the discharge states are a first stable discharge state, a second stable discharge state and a third stable discharge state, respectively.

Preferably, the first stable discharge state includes a ramp-up phase and a first stable discharge phase, the ramp-up phase is to make the current or voltage or power or pulse width from 0 to a ramp-up set value in T3ms, and the first stable discharge phase is to maintain a constant current or constant voltage or constant power or constant pulse width in T4 ms.

Preferably, the second stable discharge state is a second stable discharge period, and the second stable discharge period refers to maintaining a constant current or a constant voltage or a constant power or a constant pulse width in T6 ms.

Preferably, the third discharge state includes a third stable discharge phase and a slow-down phase, the third stable discharge phase is to maintain a constant current or a constant voltage or a constant power or a constant pulse width in T8ms, and the slow-down phase is to make the current or the voltage or the power or the pulse width from a slow-down set value to 0 in T9 ms.

Preferably, the first stable discharge and the second stable discharge interval T5ms, and the first stable discharge and the second stable discharge interval T7 ms.

The invention has the following beneficial effects: by adopting the process, a nugget is formed between the surface of the cap and the auxiliary lead through spot welding, the area of the nugget is slightly equal to the cross section area of the auxiliary lead, the nugget is smaller, the pulling load of the cap and the auxiliary lead is larger, and the cap and the auxiliary lead are not easy to break, but the pulling load of the cap and the auxiliary lead is smaller, the cap and the auxiliary lead are easy to cut, the subsequent auxiliary painting is facilitated, the auxiliary lead is cut off, the cap cannot be cut off, a crater formed on the surface of the cap after the auxiliary lead is cut off is smaller, and the overall appearance is improved while the quality of a leadless resistor is ensured.

Drawings

FIG. 1 is a block diagram of the present invention.

Fig. 2 is a structural view of a conventional auxiliary lead wire and a conventional lead-less resistance welded wire.

Fig. 3 is an external view of a conventional leadless resistor pin-cutting rear cap with auxiliary leads.

Fig. 4 is a structural view of the auxiliary lead and the leadless resistance welding of the present invention.

FIG. 5 is a schematic view of the cap after cutting the foot according to the present invention.

Fig. 6 is a schematic diagram of a welding power supply in a current mode with three discharge states.

Fig. 7 is a schematic diagram of a welding power supply in a voltage mode with three discharge states.

Fig. 8 is a schematic diagram of a welding power supply in a power mode with three discharge states.

FIG. 9 is a schematic diagram of a welding power source in a pulse width mode with three discharge states.

FIG. 10 is a schematic diagram of a welding power supply.

Fig. 11 is a welding current waveform diagram.

Fig. 12 is a graph of weld current versus nugget performance for auxiliary lead and cap formation.

Fig. 13 is a graph of weld time versus nugget performance for auxiliary lead and cap formation.

Fig. 14 is a schematic diagram of auxiliary leads approaching the caps.

Fig. 15 is a schematic view of an auxiliary lead pre-pressing cap.

Fig. 16 is a schematic view of auxiliary lead and cap bonding.

Fig. 17 is a schematic view of a second electrode detachment auxiliary lead.

FIG. 18 is a flow chart of the steps of the present invention.

Description of reference numerals: 1. a leadless resistor; 11. a resistor body; 12. a cap; 13. an auxiliary lead; a V-shaped electrode disk; 3. a clamping mouth swing arm.

Detailed Description

Referring to fig. 1-7, a leadless resistor with auxiliary leads includes a leadless resistor, the two ends of the leadless resistor are provided with auxiliary leads, the leadless resistor includes a resistor body and caps arranged at the two ends of the resistor body, a nugget is formed between the surface of the cap and the auxiliary leads by spot welding, and the area of the nugget is slightly equal to the area of the auxiliary leads. Before the auxiliary lead is not cut off, the welding spot formed on the surface of the cap by the auxiliary lead is very large from the existing product picture, the auxiliary lead can be cut off only by large longitudinal shearing force, the cap can be damaged by large force to influence the performance of the leadless resistor, and simultaneously, after the auxiliary lead is cut off, compared with the effect after cutting of the leadless resistor with the auxiliary lead manufactured by the existing welding process, the welding spot scar on the surface of the cap after the cutting foot (the cutting auxiliary lead is called as the cutting foot by the jargon of the operation) of the invention is obviously smaller than the welding spot scar after welding of the existing process, and the area of the weld scar is the cross section area of the auxiliary lead, only a small point is seen from the appearance, while the weld scar after the cutting foot of the existing product is larger and basically occupies more than half area of the whole cap, the welding tool method ensures that the longitudinal pulling load between the auxiliary lead and the cap is greatly reduced, therefore, the cutter can not damage the cap but cut off the auxiliary gravitation by lightly touching, and the automatic production efficiency of the wireless resistance is greatly improved.

the method comprises the following steps: placing a resistor body (leadless resistor) with caps at two ends into a V-shaped electrode disc, wherein the V-shaped electrode disc is disc-shaped and is used for placing the leadless resistor, the V-shaped electrode disc is electrically connected with a first electrode, the first electrode is connected with a power supply, a conductive pinch roller presses the caps, and the leadless resistor is clamped by the V-shaped electrode disc and the conductive pinch roller, so that the caps are electrically connected with the first electrode;

step two: the auxiliary lead is clamped by the clamping nozzle swing arm, the clamping nozzle swing arm is electrically connected with a second electrode, the second electrode is connected with a power supply, the clamping nozzle swing arm is made of a conductive material, and the auxiliary lead is electrically connected with the second electrode;

step three: approaching: the auxiliary lead is close to the surface of the cap by the clamping mouth swinging arm, the closing time is T1ms, the auxiliary lead and the cap are positioned on the same axis, the auxiliary lead and the cap are not electrified in the closing process, and when the auxiliary lead is contacted with the cap, the first electrode and the second electrode respectively start to be electrified;

step four: pre-pressing: the auxiliary lead is pre-pressed after contacting the cap, the pre-pressing time is T2ms, if the T2 time is too short, the first electrode discharges in the air, so as to cause desoldering, and if the T2 time is too long, the production efficiency is affected, the T2 is generally determined according to the distance between the auxiliary lead and the cap and the speed of the auxiliary lead approaching the cap, the pressure of the auxiliary lead on the surface of the cap is FKg, and the F is preferably 9.5Kg to 25 Kg; the cap is electrified to generate heat, and the pre-pressing can prevent the cap from being heated instantly to cause the cap to be broken and splashed, and is favorable for the auxiliary lead and the cap to form a nugget.

Step five: welding: after the auxiliary lead is contacted with the cap, the first electrode, the second electrode, the cap and the auxiliary lead form a welding loop, the welding power supply is used for applying discharge to the first electrode and the second electrode for a plurality of times, the welding temperature between the auxiliary lead and the cap is controlled by controlling the current, so that a nugget 4 is formed between the auxiliary lead and the cap, thereby realizing the formation of new metal crystals between the auxiliary lead and the cap, the inversion period and the inversion frequency are adopted for discharging, the inversion period is 0.25-1ms, the time interval is provided for two adjacent discharges, the auxiliary lead continuously applies pressure to the cap during the welding period, after the discharge is stopped, the welding power supply is controlled to maintain the pressure so as to ensure that the weldment is solidified to enough strength, therefore, the pulling load between the auxiliary lead and the cap is large enough, the auxiliary lead is not easily transversely broken, and the auxiliary lead is convenient to assist the subsequent code coating and oil coating process of the leadless resistor.

The discharge for several times has three discharge states, which are the first stable discharge state, the second stable discharge state and the third stable discharge state.

a. The first stable discharge state comprises a slow-rising stage and a first stable discharge stage, wherein the slow-rising stage is that the current or voltage or power or pulse width is enabled to be from 0 to a slow-rising set value (I1 or U1 or P1 or W1) in T3ms, the slow-rising set value and the slow-rising set value are set according to a contact resistance value (resistance value when a lead is in contact with a cap), the longer the T3 time is, the slower the current rises, and the better the welding effect is, the better the first stable discharge stage is that the constant current or constant voltage or constant power or constant pulse width is kept in T4ms, and the longer the first stable discharge time (T4) lasts, the larger the energy is. The current is slowly increased to prevent the cap from cracking and splashing caused by instant heating due to different expansion coefficients of different metal materials.

Assuming that the auxiliary lead is a copper wire, the current ramp-up time (T3) is 5ms, the pressure (F) continuously applied to the cap by the auxiliary lead when the current is ramped up is 9.5Kg, the ramp-up current set value (I1) is 750A, and the first stable discharge time (T4) is 5 ms;

assuming that the auxiliary lead is an iron wire, the current ramp-up time (T3) is 10ms, the auxiliary lead continuously applies pressure (F) to the cap at 9.5Kg when the current is ramped up, the ramp-up current set value (I1) is 350A, and the first stable discharge time (T4) is 5 ms;

assuming that the auxiliary lead is a nickel wire, the current ramp-up time (T3) is 25ms, the auxiliary lead continuously applies 9.5Kg of pressure (F) to the cap when the current is ramped up, the ramp-up current set value (I1) is 350A, and the first stable discharge time (T4) is 5 ms;

b. the second stable discharge state is a second stable discharge stage, and the second stable discharge stage is to maintain constant current or constant voltage or constant power or constant pulse width (I2 or U2 or P2 or W2) in T6ms for a time between T6 ms.

c. The third discharge comprises two stages, namely a third stable discharge stage and a current slow-down stage, wherein the third stable discharge stage is third discharge time, the third discharge time is between T8ms, the time of the current slow-down stage is T9ms, the current slow-down refers to a slow-down set value (I3 or U3 or P3 or W3) to 0A, the set value is set according to the melting point of the auxiliary lead, the current slow-down avoids the temperature from dropping too fast, and the welding firmness is improved,

supposing that the auxiliary lead is a copper wire, the current slow-falling time (T9) is 5ms, the auxiliary lead continuously applies pressure (F) to the cap when the current slowly falls to 9.5Kg, and the slow-falling current set value (I3) is 750A;

supposing that the auxiliary lead is an iron wire, the current slow-falling time (T9) is 10ms, the auxiliary lead continuously applies pressure (F) to the cap when the current slowly falls to 9.5Kg, and the slow-falling current set value (I3) is 350A;

supposing that the auxiliary lead is a nickel wire, the current slow-falling time (T9) is 5ms, the auxiliary lead continuously applies 9.5Kg of pressure (F) to the cap when the current slowly falls, and the slow-falling current set value (I3) is 750A;

the discharge (discharge refers to the discharge current or voltage or power or pulse width) is performed at the position where the resistance value of the whole welding loop is maximum (namely the contact position of the auxiliary lead and the cap), the material with high conductivity has low melting point, large discharge current and very short discharge time, and the discharge is sequentially performed for the first, second and third times; for example, the auxiliary lead made of copper and the cap made of copper; the material with low conductivity has high melting point, and needs a plurality of times of second stable discharge, such as slow rising, … … holding and slow falling, besides the first stable discharge and the third discharge, according to the melting point of the auxiliary lead, the interval between the first stable discharge and the second stable discharge can be T5ms, preferably 0-200ms, and the interval between the second stable discharge and the third discharge can be T7ms, preferably 0-200ms, so that the metal is fully dissolved, the cap fracture and splash caused by instant heating of different metal material expansion coefficients can be prevented, and in addition, the slow rising set value, the slow falling set value and the constant value during the second stable discharge can be different according to different metal material slow rising set values.

Step six: after welding, stopping discharging, controlling a welding power supply to perform pressure maintaining, wherein the pressure maintaining time is T10ms, the welding spot cooling crystallization needs to be performed under certain pressure, T10 is preferably 10ms-200ms (according to the melting point of the auxiliary lead), and the second electrode is separated from the lead after pressure maintaining, so that the welded leadless resistor with the auxiliary lead can be taken out.

The auxiliary lead is always applied with pressure to the cap in the whole welding process, so that the welding temperature is consistent when the auxiliary lead is in contact with the cap in each welding process, the welding purpose is achieved through multiple times of discharging (the auxiliary lead and the cap are fully dissolved to form a small nugget), and the beneficial effect of better welding quality is achieved. Discharging refers to releasing current, voltage, power, pulse width.

The invention has the following beneficial effects: according to the invention, complete liquid phase nuggets can be obtained by spot welding the lead and the cap, so that nuggets with the cross-sectional area approximately equal to that of the auxiliary lead are formed. The welding power supply is a three-phase 380V power supply, two live wires are adopted, one zero line is a two-phase 380V power supply, a three-phase finger is composed of three live wires, the phase difference of sine waves of each alternating current is 120 degrees, the voltage between the phases is 380V, the three-phase 380V power supply adopts an IGBT (insulated gate bipolar translator) inversion technology, the IGBT inversion technology adopts an AC-DC-AC-DC conversion technology, the inversion time is 0.25-1ms, the time control reaches the millisecond precision, and the control response and the control precision are greatly improved; the welding manufacturability is obviously improved by the direct current output, the pulse direct current output for welding provided by the welding power supply is small in waviness (figure 11), the defect that the workpiece is discontinuously heated by the existing alternating current zero crossing is effectively overcome, heat is concentrated, continuous direct current output is realized under the action of loop inductance, the welding heat efficiency is improved, and the welding heat input is stable. The welding time is shortened. The spot welding device is particularly suitable for spot welding of non-ferrous metal materials such as copper and aluminum, spot welding of alloy materials, spot welding of precision parts and spot welding of high-quality products, is particularly suitable for welding of non-ferrous metal materials and some materials difficult to weld, and is stable in welding process and remarkably improved in welding quality. At the same time, the electrode life is extended.

The current is regulated by the inversion pulse width, the time is regulated by the inversion period number, the welding energy can be accurately controlled by the current and the time, the welding speed is high, the frequency is high (1-4kHz), the loss is small, the power factor is improved by the direct current output, and the energy-saving effect is obvious.

The discharge refers to current or voltage or power or pulse width, and the voltage mode effectively compensates the problems of wrong displacement and pressure of a weldment, reduces welding spatter, and is suitable for non-planar workpieces such as circular parts; the power mode is to change current and voltage under consistent energy, break oxide surfaces and flatten, automatically extend electrode life, and the current mode delivers everyone's electricity regardless of resistance changes, complementing changes in part thickness. The current mode is most preferably used.

A manufacturing process of a leadless resistor comprises the following steps:

the method comprises the following steps: cutting off the auxiliary lead, clamping the auxiliary lead through the clamping mouth swing arm and welding the auxiliary lead on the surface of the cap to form the leadless resistor with the auxiliary lead;

step two: clamping auxiliary leads at two ends of the leadless resistor by a lead clamping device, and drying an oiling paint color code mark of the leadless resistor;

step three: and lightly touching and cutting the auxiliary lead by a cutting knife to form the leadless resistor.

The leadless resistor plays a role in limiting current and reducing voltage of a circuit to fuse a fuse element, an auxiliary lead needs to be welded in the manufacturing process of the leadless resistor to assist subsequent manufacturing procedures such as paint coating, color code marking and the like, and the auxiliary lead is cut (the auxiliary lead is cut) after the procedures are completed. The invention realizes point connection of the lead and the cap, has smaller pulling and shearing load between the lead and the cap but larger transverse pulling load, ensures the connection quality of dissimilar metals, is not easy to break but easy to cut, solves the problem that the quality of leadless resistance is influenced by cutting the cap due to the cutting of a pin, and improves the production efficiency.

The working principle is analyzed as follows according to the following formula:

Q＝I2Rt(J)

in the formula: q-heat of generation (J);

i-welding current (A), the current flowing through the welding loop during welding is called welding current,

r-resistance (Ω);

t-welding time(s);

the resistors include a workpiece self (auxiliary lead or cap) resistor Rw, an auxiliary lead or cap contact resistor Rc, and an electrode-workpiece contact resistor Rew. I.e. R2 Rw + Rc +2 Rew.

When the workpiece and the electrode are constant, the resistance of the workpiece depends on its resistivity. Resistivity is therefore an important property of the weldment and depends on the type of metal, the electrode and the workpiece, and the surface contact resistance between the workpiece and the workpiece. In terms of the type of metal, metals having poor conductivity (e.g., stainless steel) have high resistivity, and metals having good conductivity (e.g., aluminum alloy) have low resistivity, and therefore, spot welding of stainless steel is likely to generate heat and is difficult to dissipate heat, and spot welding of aluminum alloy is likely to generate heat and is difficult to dissipate heat. In the aspect of surface contact resistance of a workpiece and a workpiece, when two welding parts with different thicknesses are subjected to spot welding, more heat is generated due to larger internal resistance of the thick parts; and the thin piece has smaller internal resistance and generates less heat.

The effect of adjusting the welding current on the performance of the nugget formed by the auxiliary lead and the cap is shown in fig. 12, the steep part of the curve of the AB segment. Because the welding current is small, the intensity of a heat source is insufficient, a nugget cannot be formed, or the size of the nugget is very small, so that the tensile and shearing load of the welding point is low and unstable.

The curve of the BC segment rises smoothly. With the increase of welding current, the heat productivity of an internal heat source is increased sharply, the size of a nugget is increased stably, and therefore the tensile and shearing load of a welding point is increased continuously (generally, the tensile and shearing load of the welding point is in direct proportion to the diameter of the nugget). In the area close to the point C, because the warping-off between the plates limits the enlargement of the diameter of the nugget and the temperature field from entering a quasi-stable state, the change of the tensile and shearing loads of the welding point is not large. After the point C, the current is too large, so that the heating is too strong, the defects of metal overheating, splashing, too deep indentation and the like are caused, and the nugget performance is reduced.

Fig. 12 also shows that the thicker the weldment, the steeper the BC section, i.e. the more sensitive the change in welding current I is to the effect of the weld pull-shear load.

The size of a nugget formed on the surface of the cap by the auxiliary lead in the process is very small, the tensile and shearing load of a welding spot is continuously improved, but the auxiliary lead can be slightly broken by a cutter.

The effect of weld time on nugget performance is similar to that of the weld current, as shown in fig. 13. The curve does not drop immediately after point C because the plastic ring expands somewhat despite the saturation of the nugget size, and the heating rate of the heat source is relatively slow, so that no splashing occurs in general; the influence of the welding time on the tensile load should be considered for the nugget of a metal material (hardenable steel, molybdenum alloy, etc.) which is subjected to a dynamic load or tends to be brittle, because the welding time has a large influence on the ductility ratio representing the plasticity index of the nugget.

The higher the melting point, the longer the discharge time is required, and the current, voltage, power, or the like is not necessarily required to be large.

Too much or too little pressure of the auxiliary lead on the cap leads to a reduction in the load-bearing capacity of the nugget and to a greater dispersion, especially with respect to tensile loads. When the pressure of the auxiliary lead wire on the cap is too small, the heating speed is higher than the expansion speed of the plastic ring due to too high current density because the plastic deformation range and the deformation degree of the metal of the welding area are insufficient, so that severe splashing is generated. This not only causes changes in the shape and size of the nuggets, but also is environmentally polluting and unsafe. The large pressure of the auxiliary lead wire on the cap increases the contact area of the welding area, reduces the total resistance and the current density, increases the heat dissipation of the welding area and reduces the size of the nugget.

It is considered that the welding current or the welding time is appropriately increased while the pressure of the auxiliary lead to the cap is increased to maintain the heating degree of the welding zone constant. Meanwhile, due to the increase of the pressure, the adverse effect of pressure fluctuation borne by a welding area on the strength of the nugget caused by factors such as the gap between the auxiliary lead and the cap, uneven rigidity and the like can be eliminated. In this case, the strength of the solder joint is maintained, and the stability is greatly improved.

The pressure of the auxiliary lead to the cap should also be selected taking into account the following factors: the pressure of the metal with higher high-temperature strength is correspondingly increased; the harder the welding specification, the higher the pressure should be; in order to reduce the heating insufficiency of the welding zone caused by adopting smaller electrode pressure, a saddle-shaped pressure change curve can be adopted.

The following table is the relevant parameters:

the above embodiments are only for describing the preferred embodiments of the present invention, and are not intended to limit the scope of the present invention, and various modifications and improvements made to the technical solution of the present invention by those skilled in the art without departing from the spirit of the design of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A welding method of a leadless resistor with auxiliary leads comprises the leadless resistor, the two ends of the leadless resistor are provided with the auxiliary leads, the leadless resistor comprises a resistor body and caps arranged at the two ends of the resistor body, a nugget is formed between the surface of the cap and the auxiliary leads through spot welding, the area of the nugget is equal to the cross section area of the auxiliary leads,

the welding method of the leadless resistor with the auxiliary lead is characterized in that: the method comprises the following steps:

step three: approaching: the auxiliary lead is close to the surface of the cap, the closing time is T1ms, no discharge occurs in the closing process, and when the auxiliary lead is in contact with the cap, the first electrode and the second electrode are respectively electrified;

step four: and welding, namely after the auxiliary lead is contacted with the cap, forming a welding loop by the first electrode, the second electrode, the cap and the lead, applying a plurality of times of discharge on the first electrode and the second electrode by a welding power supply, wherein the discharge states are a first stable discharge state, a second stable discharge state and a third stable discharge state respectively, the first stable discharge state comprises a slow-rising stage and a first stable discharge stage, the third discharge state comprises a third stable discharge stage and a current slow-falling stage, so that the auxiliary lead and the cap form a nugget on the surface of the cap, welding is completed, the second electrode is separated from the lead, and the welded leadless resistor with the auxiliary lead can be taken out.

2. The method of claim 1, wherein the method comprises the steps of: after the auxiliary lead is cut off, the area of a crater formed on the surface of the cap is the cross-sectional area of the auxiliary lead.

3. A method of welding a leadless resistor with auxiliary leads as defined in claim 1, wherein: after the third step, the auxiliary lead needs to be contacted with the cap and pressed for a certain pre-pressing time, the pre-pressing time is T2ms, the pressure applied to the auxiliary lead on the surface of the cap in the pre-pressing process is FKg, and a saddle-shaped pressure change curve can be adopted.

4. A method of welding a leadless resistor with auxiliary leads as defined in claim 1, wherein: and after welding, controlling the welding power supply to perform pressure maintaining for T10 ms.

5. A method of welding a leadless resistor with auxiliary leads as defined in claim 1, wherein: the gradual rising stage refers to that the current or voltage or power or pulse width is gradually increased from 0 to a set value in T3ms, and the first stable discharge stage refers to that the constant current or constant voltage or constant power or constant pulse width is kept in T4 ms.

6. A method of welding a leadless resistor with auxiliary leads as defined in claim 1, wherein: the second stable discharge state is a second stable discharge stage, and the second stable discharge stage is to maintain constant current or constant voltage or constant power or constant pulse width in T6 ms.

7. A method of welding a leadless resistor with auxiliary leads as defined in claim 1, wherein: the third stable discharge phase is to keep constant current or constant voltage or constant power or constant pulse width in T8ms, and the slow-down phase is to make the current or voltage or power or pulse width from a slow-down set value to 0 in T9 ms.

8. A method for welding a leadless resistor with auxiliary leads according to claim 1, wherein: the first and second stable discharge intervals T5ms, and the first and second stable discharge intervals T7 ms.