CN111243802A - Leadless resistor with auxiliary lead and welding method - Google Patents

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 manufacturing method of a leadless resistor, in particular to a leadless resistor with auxiliary leads, a welding tooling method and a manufacturing process of the leadless resistor.

Background technique

Leadless cylindrical resistors are widely used in the electronics industry. Leadless resistors can be patched by pasting, so the demand for leadless resistors is getting higher and higher. At present, there are the following methods for leadless resistors:

1. Leadless film resistor (with lead paint)

First coat the magnetic rod cap, cut the resistance value, weld the body cap with the resistance value after cutting to the lead wire, fix the lead wire through the equipment, paint and color code printing, and then cut the feet (that is, cut off the lead just welded) , The disadvantage of this process is that although the cap is well tinned, it is easy to cut the cap and affect the quality of the leadless film resistor.

2. Leadless wirewound resistor (with lead paint)

First white rod cap, winding, (with nickel-chromium wire or manganese copper wire, constantan wire wound on the white rod), after winding, there is resistance value body cap and lead welding, and then paint and color code Printing, and then cutting the feet, the disadvantage of this process is that although the cap is well tinned, it is easy to cut the cap and affect the quality of the leadless wire resistance.

Whether it is a leadless film resistor or a leadless wirewound resistor, the leadless resistor needs to be welded with auxiliary leads at both ends of the resistor during the production process to assist the subsequent production processes such as painting and color coding, etc., in order to be effective and suitable for the production line method. Lead resistance, after completing the above process, cut the feet (cut off the auxiliary lead), and after welding the auxiliary lead and the cap through the existing process, the solder joint between the auxiliary lead and the cap is a planar structure, as shown in Figure 2, after the coating If the feet are cut after painting, the welding scars formed on the surface of the cap will be large, as shown in Figure 3, resulting in a large tensile shear load between the auxiliary lead and the cap, so that the feet need to be cut (cut off the auxiliary lead) after the resistance painting. It is easy to cut the cap and affect the quality of the leadless resistor. Secondly, the welding scars formed on the surface of the cap at both ends of the leadless resistor are large, and it is not easy to cut off, which affects the quality and appearance of the leadless resistor.

SUMMARY OF THE INVENTION

In order to solve the above problems, the present invention provides a leadless resistor with auxiliary leads and a welding tooling method.

In order to achieve the above object, the present invention adopts the following technical scheme: a leadless resistor with auxiliary leads, including a leadless resistor, the two ends of the leadless resistor are provided with auxiliary leads, and the leadless resistor includes: The resistor body and the caps arranged at both ends of the resistor body, the surface of the cap and the auxiliary lead wire are spot welded to form a nugget, and the area of the nugget is slightly equal to the cross-sectional area of the auxiliary lead wire.

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

A welding method for a leadless resistor with auxiliary leads, comprising the following steps:

Step 1: electrically connect the cap to the first electrode, and the first electrode is connected to the welding power source;

Step 2: electrically connect the auxiliary lead to the second electrode, and the second electrode is connected to the welding power source;

Step 3: Approach: The auxiliary lead is approaching the surface of the cap, and the approaching time is T1ms, no discharge during the approach, and the discharge starts when the auxiliary lead contacts the cap;

Step 4: Welding: After the auxiliary lead is in contact with the cap, the first electrode, the second electrode, the cap, and the lead form a welding circuit, and the welding is completed after several discharges are applied to the first electrode and the second electrode by the welding power source. When the second electrode is separated from the lead, the soldered leadless resistor with auxiliary lead can be taken out.

Preferably, after step 3, the auxiliary lead needs to be contacted with the cap and pressed for a certain pre-pressing time, the pre-pressing time is T2ms, and the pressure of the auxiliary lead on the surface of the cap during the pre-pressing process is FKg.

Preferably, after the welding is completed, the discharge is stopped, and the welding power source is controlled to maintain pressure, and the pressure maintaining time is T10ms.

Preferably, in step 5, several discharges have three discharge states, and the discharge states are respectively the first stable discharge state, the second stable discharge state, and the third discharge state.

Preferably, the first stable discharge state includes a ramp-up stage and a first stable discharge stage, and the ramp-up stage refers to making the current or voltage or power or pulse width from 0 to a ramp-up set value within T3ms, The first stable discharge stage refers to maintaining constant current or constant voltage or constant power or constant pulse width within T4ms.

Preferably, the second stable discharge state is the second stable discharge stage, and the second stable discharge stage refers to maintaining a constant current or constant voltage or constant power or constant pulse width within T6ms.

Preferably, the third discharge state includes a third stable discharge stage and a slow drop stage, and the third stable discharge stage refers to maintaining a constant current or constant voltage or constant power or constant pulse width within T8ms, and the slow drop stage It means that the current or voltage or power or pulse width is slowly decreased from the set value to 0 within T9ms.

Preferably, the interval between the first stable discharge and the second stable discharge is T5ms, and the interval between the first stable discharge and the second stable discharge is T7ms.

The present invention has the beneficial effects: by adopting the process of the present invention, a nugget is formed by spot welding between the surface of the cap and the auxiliary lead, the area of the nugget is slightly equal to the cross-sectional area of the auxiliary lead, the nugget is smaller, and the cap and the auxiliary lead The pulling load is large and it is not easy to break, but the shearing load of the cap and the auxiliary lead is small and easy to cut, which is convenient for subsequent auxiliary painting and cutting of the auxiliary lead, and the cutting will not cut the cap. The weld scar formed on the surface is smaller, which improves the overall appearance while ensuring the quality of the leadless resistor.

Description of drawings

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

FIG. 2 is a structural diagram of the conventional auxiliary lead and leadless resistance welding.

FIG. 3 is a schematic diagram of the appearance of the cap after cutting the legs of the existing leadless resistor with auxiliary leads.

FIG. 4 is a structural diagram of the present invention after the auxiliary lead and the leadless resistance are welded.

FIG. 5 is a schematic view of the appearance of the cap after the foot is cut in accordance with the present invention.

FIG. 6 is a schematic diagram of the three-time discharge state of the welding power source in the current mode.

FIG. 7 is a schematic diagram of the three-time discharge state of the welding power source in the voltage mode.

FIG. 8 is a schematic diagram of the three-discharge state of the welding power source in the power mode.

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

Figure 10 is a schematic diagram of the principle of the welding power source.

Fig. 11 is a welding current waveform diagram.

Figure 12 is a graph of the nugget performance of welding current on auxiliary leads and caps.

Figure 13 is a graph of the nugget performance of welding time versus auxiliary lead and cap formation.

Figure 14 is a schematic diagram of the auxiliary lead near the cap.

Figure 15 is a schematic diagram of the auxiliary lead pre-pressing cap.

Figure 16 is a schematic diagram of the welding of auxiliary leads and caps.

FIG. 17 is a schematic diagram of the second electrode being separated from the auxiliary lead.

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

Description of reference numerals: 1. Leadless resistor; 11. Resistor body; 12. Cap; 13. Auxiliary lead; 2. V-shaped electrode plate;

Detailed ways

Please refer to Figures 1-7, a leadless resistor with auxiliary leads, including a leadless resistor, auxiliary leads are arranged at both ends of the leadless resistor, and the leadless resistor includes a resistor body and a Both ends of the resistor body are capped, and a nugget is formed between the cap surface and the auxiliary lead by spot welding, and the area of the nugget is slightly equal to the area of the auxiliary lead. Before cutting off the auxiliary lead, it can be seen from the existing product picture that the solder joint formed by the auxiliary lead on the surface of the cap is very large, and a large longitudinal shear force is required to cut off the auxiliary lead. The performance of the lead resistance, at the same time, after the auxiliary lead is cut, compared with the effect of the leadless resistor with the auxiliary lead made by the existing welding process, the cutting foot of the present invention (the cutting of the auxiliary lead is called the cutting foot in the terminology). ) The welding spot scar on the surface of the rear cap is obviously smaller than the welding spot scar of the existing process, and the area of the welding scar is the cross-sectional area of the auxiliary lead, and there is only one small point from the appearance, and the welding scar of the existing product after cutting the foot is smaller than that of the existing product. The welding tooling method of the present invention not only ensures the lateral pulling load between the auxiliary lead and the cap, but also greatly reduces the longitudinal shear load between the auxiliary lead and the cap, thereby making the cutting knife lighter A light touch can cut off the auxiliary gravitational force without damaging the cap, which greatly improves the automatic production efficiency of the wireless lead resistor.

A welding method for leadless resistors with auxiliary leads is:

Step 1: Place the resistor body (wireless resistor) with caps at both ends into the V-shaped electrode disk, the V-shaped electrode disk is disk-shaped and used to place the leadless resistor, and the V-shaped electrode disk is electrically connected to the first electrode , the first electrode is connected to the power supply, the conductive voltage wheel presses the cap, and the leadless resistance is clamped by the V-shaped electrode plate and the conductive voltage wheel, so that the cap is electrically connected to the first electrode;

Step 2: the auxiliary lead is clamped by the clamping nozzle swing arm, the clamping nozzle swing arm is electrically connected to the second electrode, the second electrode is connected to the power source, the clamping nozzle swing arm is made of conductive material, and the auxiliary lead is electrically connected to the second electrode;

Step 3: Approach: The clamping nozzle swing arm moves the auxiliary lead to the surface of the cap, and the approach time is T1ms, so that the auxiliary lead and the cap are on the same axis, and no electricity is supplied during the approaching process. One electrode and the second electrode are respectively energized;

Step 4: Pre-pressing: After the auxiliary lead contacts the cap, pre-press first. The pre-pressing time is T2ms. If the T2 time is too short, the first electrode will discharge in the air, resulting in desoldering. If the T2 time is too long, the production efficiency will be affected. T2 is generally determined according to the distance between the auxiliary lead and the cap and the speed at which the auxiliary lead approaches the cap. The pressure on the surface of the cap by the auxiliary lead is FKg, and F is preferably 9.5Kg to 25Kg; when the cap is energized, heat will be generated and pre- The pressure can prevent the cap from being heated in an instant, causing the cap to crack and splash, and facilitate the formation of a nugget between the auxiliary lead and the cap.

Step 5: Welding: After the auxiliary lead is in contact with the cap, the first electrode, the second electrode, the cap, and the auxiliary lead form a welding circuit, and several discharges are applied to the first electrode and the second electrode through the welding power The size of the current is used to control the welding temperature between the auxiliary lead and the cap, so that a nugget 4 is formed between the auxiliary lead and the cap, so as to realize the formation of new metal crystals between the auxiliary lead and the cap. Frequency, the inverter cycle is 0.25-1ms, and there is a time interval between two adjacent discharges. During welding, the auxiliary lead continues to exert pressure on the cap. After the discharge stops, control the welding power source to maintain pressure to ensure that the weldment solidifies to sufficient strength. Therefore, the pulling load between the auxiliary lead and the cap is large enough, and it is not easy to be pulled off laterally, which is convenient for the auxiliary lead to assist the subsequent coding and oiling process of the leadless resistor.

Several discharges have three discharge states, and the discharge states are the first stable discharge state, the second stable discharge state, and the third discharge state.

a. The first stable discharge state includes the ramp-up stage and the first stable discharge stage. The ramp-up stage refers to making the current or voltage or power or pulse width from 0 to the ramp-up set value (I1 within T3ms) or U1 or P1 or W1), the ramp-up time and ramp-up setting value are set according to the contact resistance (resistance value when the lead is in contact with the cap). The longer the T3 time, the slower the current rises and the better the welding effect. The first stable discharge stage refers to maintaining a constant current or constant voltage or constant power or constant pulse width within T4ms. The longer the first stable discharge time (T4) lasts, the greater the energy. The slow rise of the current can prevent the cap from cracking and splashing due to the instantaneous heating of different metal materials with different expansion coefficients.

Assuming that the auxiliary lead is copper wire, the current ramp-up time (T3) is 5ms, the auxiliary lead continues to exert pressure (F) on the cap when the current ramps up, and the pressure (F) is 9.5Kg, the ramp-up current setting value (I1) is 750A, the first The sub-stable discharge time (T4) is 5ms;

Assuming that the auxiliary lead is an iron wire, the current ramp-up time (T3) is 10ms, the auxiliary lead continues to exert pressure (F) on the cap when the current ramps up, and the pressure (F) is 9.5Kg, the ramp-up current setting value (I1) is 350A, the first The sub-stable discharge time (T4) is 5ms;

Assuming that the auxiliary lead is nickel wire, the current ramp-up time (T3) is 25ms, the auxiliary lead continues to exert pressure (F) on the cap when the current ramps up, and the pressure (F) is 9.5Kg, and the ramp-up current setting value (I1) is 350A. The sub-stable discharge time (T4) is 5ms;

b. The second stable discharge state is the second stable discharge stage, and the second stable discharge stage refers to maintaining a constant current or constant voltage or constant power or constant pulse width (I2 or U2 or P2 or W2 within T6ms) ), the time is between T6ms.

c. The third discharge includes two stages, namely the third stable discharge stage and the current slow down stage. The third stable discharge stage is the third discharge time. The third discharge time is between T8ms and the current slows down. The time of the drop stage is T9ms. The current slow drop refers to the slow drop from the 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, and the current drops slowly to avoid temperature drop. Too fast, improve the welding firmness,

Assuming that the auxiliary lead is copper wire, the current slow-down time (T9) is 5ms, the auxiliary lead continues to exert pressure (F) on the cap when the current slows down, and the pressure (F) is 9.5Kg, and the slow-down current setting value (I3) is 750A;

Assuming that the auxiliary lead is iron wire, the current slow down time (T9) is 10ms, the auxiliary lead continues to exert pressure (F) on the cap when the current slows down, and the pressure (F) is 9.5Kg, and the slow down current setting value (I3) is 350A;

Assuming that the auxiliary lead is nickel wire, the current slow down time (T9) is 5ms, the auxiliary lead continues to exert pressure (F) on the cap when the current slows down, and the pressure (F) is 9.5Kg, and the slow down current setting value (I3) is 750A;

Discharge (discharge refers to the release of current or voltage or power or pulse width) is at the point where the resistance of the entire welding circuit is the largest (that is, where the auxiliary lead is in contact with the cap), the material with high conductivity has a lower melting point and a larger release current. The release time is very short, and it undergoes the first, second, and third discharges in sequence; for example, copper auxiliary leads and copper caps; materials with low conductivity have high melting points, in addition to the first stable discharge and the third discharge, also need Multiple second stable discharges, such as slowly rising, maintaining...maintaining, slowly falling, 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, in the first stable discharge The interval between the second stable discharge and the third discharge can be T7ms, preferably 0-200ms, so that the metal can be fully dissolved to prevent the cap from cracking and splashing due to the different expansion coefficients of different metal materials. , the slow-down setting value and the constant value during the second stable discharge can be different.

Step 6: After welding, the discharge is stopped, and the welding power source is controlled to maintain pressure. The pressure holding time is T10ms. The cooling and crystallization of the solder joint needs to be carried out under a certain pressure. After pressing, the second electrode is separated from the lead, and the soldered leadless resistor with auxiliary leads can be taken out.

The auxiliary lead has been applying pressure to the cap during the whole welding process to ensure that the resistance of the auxiliary lead and the cap can be consistent every time the welding process is in contact with the cap to ensure the same welding temperature. Fully dissolved to form smaller nuggets), the beneficial effect of better welding quality. Discharge refers to the release of current, voltage, power, and pulse width.

The present invention has the beneficial effects: the present invention can obtain a complete liquid-phase nugget by spot welding the lead and the cap, thereby forming a nugget with a cross-sectional area slightly equal to that of the auxiliary lead. The welding power source is a three-phase 380V power supply, two live wires, and a zero wire is a two-phase 380V power source. The three-phase finger is composed of three live wires. The phase difference of the AC sine wave of each phase is 120 degrees. 380v, three-phase 380V power supply adopts IGBT inverter technology, IGBT inverter technology adopts AC-DC-AC-DC conversion technology, the inverter time is 0.25-1ms, the time control reaches millisecond precision, and the control response and control accuracy are greatly improved ; The DC output significantly improves the welding manufacturability. The pulsating DC output for welding provided by the welding power source has a small waviness (Fig. 11), which effectively solves the shortcomings of the existing AC zero-crossing and discontinuous heating of the workpiece. The lower part is continuous DC output, which improves the welding thermal efficiency and stabilizes the welding heat input. Welding time is shortened. It is especially 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. It is especially suitable for welding of non-ferrous metal materials and some difficult-to-weld materials, and the welding process is stable. , Welding quality is significantly improved. At the same time, the electrode life is extended.

Current is adjusted by inverter pulse width, time is adjusted by inverter cycle number, welding energy can be precisely controlled by current and time, high welding speed, high frequency (1-4kHz), small loss, DC output improves power factor, energy saving The effect is obvious.

The term “discharge” in the present invention refers to current or voltage or power or pulse width. The voltage mode effectively compensates for the erroneous displacement and pressure of the weldment, reduces welding spatter, and is suitable for non-planar workpieces, such as round parts; the power mode is consistent with the energy Changing the current and voltage, cracking the oxidized surface and flattening, automatically prolongs the electrode life, and the current mode ignores the resistance change under the condition that each person's electricity is delivered, supplementing the change in the thickness of the part. The best is to use current mode.

A manufacturing process of a leadless resistor, comprising the following steps:

Step 1: Cut off the auxiliary lead, clamp and weld the auxiliary lead on the surface of the cap through the clamp nozzle swing arm to form a leadless resistor with an auxiliary lead;

Step 2: Clamp the auxiliary leads at both ends of the leadless resistor through the lead wire clamping device, paint the leadless resistor with a color code mark and bake it to dry;

Step 3: Cut off the auxiliary lead by lightly touching the cutting knife to form a leadless resistance.

The leadless resistor is a current-limiting step-down resistor that fuses the fuse element in the circuit. The leadless resistor needs to be welded with auxiliary leads during the production process to assist the subsequent production processes such as painting and color coding. After the above processes are completed, the feet are cut. (Remove the auxiliary lead), the existing process makes the auxiliary lead and the cap of the lead-free resistor as a planar connection, which leads to a large tensile and shear load between the auxiliary lead and the cap, and the cap is easily cut when the feet are cut, which affects the lead-free resistance. quality. The invention realizes the point connection between the lead and the cap, the pull and shear load between the lead and the cap is small, but the lateral pull load is large, while ensuring the quality of the connection of dissimilar metals, it is not easy to be broken but easy to cut, and solves the problem of cutting Cutting off the cap will affect the quality of the leadless resistor and improve the production efficiency.

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

Q=I2Rt(J)

In the formula: Q—the heat generated (J);

I——Welding current (A), the current flowing through the welding circuit during welding is called welding current,

R——resistance (Ω);

t——welding time (s);

Among them, the resistance includes the resistance Rw of the workpiece itself (auxiliary lead or cap), the contact resistance Rc of the auxiliary lead or the cap, and the contact resistance Rew between the electrode and the workpiece. That is, R=2Rw+Rc+2Rew.

When the workpiece and the electrode are fixed, the resistance of the workpiece depends on its resistivity. Therefore, the resistivity is an important property of the weldment, which depends on the metal type, the surface contact resistance between the electrode and the workpiece, and the workpiece and the workpiece. In terms of metal types, metals with poor conductivity (such as stainless steel) have high resistivity, and metals with good conductivity (such as aluminum alloys) have low resistivity. Therefore, it is easy to generate heat and difficult to dissipate heat when spot welding stainless steel. Spot welding aluminum alloys It is difficult to generate heat and easy to dissipate heat. In terms of the surface contact resistance between the workpiece and the workpiece, when two pieces of weldment with different thicknesses are spot welded, the internal resistance of the thick piece is large, and more heat is generated; while the internal resistance of the thin piece is small, and less heat is generated.

The effect of adjusting the welding current on the performance of the nugget formed by the auxiliary lead and the cap is shown in Figure 12, the steeper segment of the AB segment curve. Due to the small welding current, the strength of the heat source is insufficient to form a nugget or the size of the nugget is very small, so the tensile shear load of the welding spot is low and very unstable.

The BC segment curve rises steadily. With the increase of welding current, the calorific value of the internal heat source increases sharply, and the size of the nugget increases steadily, so the tensile shear load of the solder joint increases continuously (generally, the tensile shear load of the solder joint is proportional to the diameter of the nugget). In the area near point C, since the warp between plates limits the expansion of the nugget diameter and the temperature field enters a quasi-steady state, the tensile shear load of the solder joints does not change much. After point C, because the current is too large, the heating is too strong, causing defects such as overheating of the metal, splashing, and deep indentation, and the performance of the nugget decreases.

Figure 12 also shows that the thicker the weldment, the steeper the BC section, that is, the more sensitive the change of the welding current I is to the influence of the tensile and shear load of the weld.

The size of the nugget formed on the surface of the cap cover by the auxiliary lead wire by the process of the invention is very small, and the pulling and shearing load of the solder joint is continuously increased, but the auxiliary lead wire can be gently broken by the cutting knife.

The effect of welding time on nugget performance is similar to that of welding current, as shown in Figure 13. The curve does not drop immediately after point C. This is because although the size of the nugget has reached saturation, the plastic ring can still expand to a certain extent. In addition, the heating rate of the heat source is relatively slow, so there is generally no splash; The ductility ratio of the nuclear plasticity index has a great influence. Therefore, for the point nugget of metal materials (hardenable steel, molybdenum alloy, etc.) that are subjected to dynamic load or tend to be brittle, the influence of welding time on tensile load should also be considered.

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

Too much or too little pressure on the cap by the auxiliary lead will reduce the load-carrying capacity of the nugget and increase the dispersion, especially on the tensile load. When the pressure of the auxiliary lead to the cap is too small, due to the insufficient plastic deformation range and deformation degree of the metal in the welding zone, the heating speed is greater than the expansion speed of the plastic ring due to the excessive current density, resulting in serious splashing. This not only changes the shape and size of the nugget, but also pollutes the environment and is unsafe. The large pressure of the auxiliary lead on the cap will increase the contact area of the welding area, reduce the total resistance and current density, increase the heat dissipation of the welding area, and reduce the size of the nugget.

It is generally believed that while increasing the pressure of the auxiliary lead on the cap, the welding current or welding time should be appropriately increased to maintain the heating degree of the welding zone unchanged. At the same time, due to the increase in pressure, the adverse effects of pressure fluctuations on the nugget strength caused by the gap between the auxiliary lead and the cap, and the uneven rigidity of the welding area can be eliminated. At this time, not only the strength of the solder joints remains unchanged, but also the stability can be greatly improved.

The following factors should also be considered in the selection of the pressure of the auxiliary lead to the cap: the higher the high temperature strength of the metal, the higher the pressure; the harder the welding specification, the higher the pressure; in order to reduce the pressure caused by the use of smaller electrodes If the heating of the welding area is insufficient, a saddle pressure curve can be used.

The following table is the relevant parameters:

The above embodiments are only to describe the preferred embodiments of the present invention, and do not limit the scope of the present invention. On the premise of not departing from the design spirit of the present invention, various modifications and variations of the technical solutions of the present invention made by ordinary engineers and technicians in the art Improvements should all fall within the protection scope determined by the claims of the present invention.

Claims (10)

1. The utility model provides a leadless resistor with supplementary lead wire, includes leadless resistor, leadless resistor both ends be equipped with supplementary lead wire, leadless resistor include the resistance body and locate resistance body both ends cap, its characterized in that: and a nugget is formed between the surface of the cap and the auxiliary lead through spot welding, and the area of the nugget is slightly equal to the cross-sectional area of the auxiliary lead.

2. The leadless resistor with auxiliary leads of claim 1, wherein: 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: the method 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 when the auxiliary lead is in contact with the cap, the first electrode and the second electrode respectively start to be electrified;

step four: and 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, applying discharge on the first electrode and the second electrode for a plurality of times by a welding power supply to ensure that the auxiliary wire and the cap form a nugget on the surface of the cap, completing welding to ensure that the second electrode is separated from the lead, and taking out the welded leadless resistor with the auxiliary lead.

4. A method of welding a leadless resistor with auxiliary leads as defined in claim 3, wherein: after the third step, the auxiliary lead needs to be contacted with the cap and pressed for a pre-pressing time, the pre-pressing time is T2ms, and the pressure applied to the surface of the cap by the auxiliary lead during the pre-pressing process is FKg.

5. A method of welding a leadless resistor with auxiliary leads as defined in claim 3, wherein: and after welding, controlling the welding power supply to perform pressure maintaining for T10 ms.

6. A method of welding a leadless resistor with auxiliary leads as defined in claim 3, wherein: in the fifth step, the discharge for a plurality of times has 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.

7. A method of welding a leadless resistor with auxiliary leads as defined in claim 4, wherein: the first stable discharge state comprises a gradual rising stage and a first stable discharge stage, the gradual rising stage is to enable the current or the voltage or the power or the pulse width to be gradually increased from 0 to a set value in T3ms, and the first stable discharge stage is to keep constant current or constant voltage or constant power or constant pulse width in T4 ms.

8. A method of welding a leadless resistor with auxiliary leads as defined in claim 4, wherein: the second stable discharge state is a second stable discharge stage, and the second stable discharge stage is to maintain a constant current or a constant voltage or a constant power or a constant pulse width in T6 ms.

9. A method of welding a leadless resistor with auxiliary leads as defined in claim 4, wherein: the third discharge state comprises a third stable discharge phase and a slow-down phase, 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.

10. A method of welding a leadless resistor with auxiliary leads as defined in claim 4, wherein: the first and second stable discharge intervals T5ms, and the first and second stable discharge intervals T7 ms.

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