JP2007038227A - Welding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a welding (sealing) method of an inverter type resistance welding machine for welding a work by the welding current for rectifying the current of the frequency higher than the frequency of the power supply which can obtain the best welded state and can reduce the entering of splash (contamination) into a closed container during the welding. <P>SOLUTION: The entering of the contamination into the container is suppressed to enhance the airtightness between a base part and a lid, and the joining strength therebetween. In the inverter type welding condition, the high frequency is varied by the inverter. A welding means is used, in which a work pressed and held between welding electrodes is welded by running the welding current obtained by rectifying the current of the frequency higher than the frequency of the power supply. The set time before the predetermined welding temperature is reached is set to be 5 ms, and the welding condition thereof is that the pressure (force) of 1.45 kN is applied, and the electric current of 10.5 kA is applied for 10 ms. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a welding (sealing) method in an inverter type resistance welding apparatus that welds an object to be welded with a welding current obtained by rectifying a current having a frequency higher than a power supply frequency.

  With the recent high functionality, high precision, miniaturization, and weight reduction of electronic devices, similar problems have been demanded for electronic components mounted on these electronic devices. For example, even when taking a container structure of an electronic component, the present invention has been addressed to improve the above-described requirements by developing a ceramic material instead of a conventional metal container.

  On the other hand, when a high-quality hermetic sealing environment using a metal container (base, lid) or the like is required, sealing that realizes a hermetic environment is performed by a conventionally used sealing method. ing. For example, crystal resonators (hermetic seal and can type) are welded and sealed with a welding machine such as resistance welding (capacitor type) or cold weld. Although inverter-type welding has existed since a long time ago, there were circumstances that could not be introduced because the equipment cost, that is, the inverter-type welding machine was very expensive. Note that current, time, and pressurization (force) are the main factors for ideal welding (sealing) conditions.

JP 2000-158148 A JP, 2001-105155, A In addition to the prior art document specified by the above-mentioned prior art document information, the applicant has not found prior art documents related to the present invention by the time of filing of the present application. .

As described in the conventional problems, recently, ceramic materials and resin materials are used instead of metallic materials containers and lids. Currently, it is mass-produced with compact sealing devices such as welding. However, taking a crystal resonator as an example, it is highly stable and the frequency fluctuation with respect to the change with time is usually 1 × 10 ⁻⁶ frequency stability to 1 × 10 ⁻⁹ frequency stability. In the case where the requirement for this becomes extremely small, welding (sealing) by resistance welding that has been conventionally used is still used.

  Here, the conventional welding (sealing) method will be briefly described. As shown in FIG. 2, as a container made of metal, a base portion and a lid portion are press-clamped between welding electrodes and an electric current is applied. In principle, the contact portion between the base portion and the lid portion is melted and sealed. FIG. 2A is a conceptual diagram that constitutes welding, FIG. 2B is a conceptual diagram that shows a state of a joint before and after welding, and FIG. 2C is a conceptual diagram that shows a nugget.

  For this reason, it is conceivable that welding dust that scatters from the welded part scatters around the joint, and in some cases scatters from the welded part to the inside of the container.

  By the way, the current control method of welding is roughly classified into a capacitor type and an inverter type. In contrast to the capacitor type, where welding equipment is relatively inexpensive, it is not possible to set detailed welding conditions from the form in which the current stored in the capacitor is instantaneously discharged. On the other hand, while the inverter type can set conditions in detail by changing the frequency, there is one aspect that the welding equipment becomes expensive.

  However, the situation in which the welding dust that scatters from the above-described welded part scatters around the joint and, in some cases, scatters from the welded part to the inside of the container occurs similarly in both the capacitor type and the inverter type. In particular, when the temperature rises and exceeds the melting temperature limit of the welded part, the molten metal is scattered as contamination, and the scattered metal component adheres to the quartz surface stored inside the joined container, deteriorating the electrical characteristics. There is a problem to say.

  In order to solve the above-mentioned problems, the present invention uses welding means for welding an object to be welded pressed between welding electrodes by energization of a welding current obtained by rectifying a current having a frequency higher than a power frequency. In the welding method of inverter type welding in which the frequency is varied by an inverter, the set time until reaching a predetermined welding temperature is set to 5 ms.

  At this time, the welding condition at the predetermined temperature is an inverter type welding method characterized in that a pressurization (force) is 1.45 kN and an energization current of 10.5 kA is energized for 10 ms.

  In short, in the present invention, when the base portion and the lid portion, which are metal containers, are welded by resistance welding, in order to adjust the amount of metal components scattered during welding, the inventor has an inverter-type welding. The best welding conditions were experimentally obtained by solving various problems (insufficient joint strength, missing joints, etc.) that occur during sealing, the welding efficiency and the welding time. As a result, the problem is solved by suppressing the entry of contamination into the container and improving the airtightness and bonding strength of the base portion and the lid portion.

  As described above, according to the welding method of the present invention, it is possible to obtain a high-quality product by reducing the intrusion of contamination inside the vacuum vessel, thereby realizing an improvement in yield and a reduction in manufacturing cost. Can do.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. In each figure, the same numerals indicate the same objects. FIG. 1 is a graph showing an example of welding conditions. Fig. 1 (a) shows the welding current on the vertical axis and the welding current application time on the horizontal axis. Fig. 1 (b) shows the welding temperature on the vertical axis and the energization time required for welding on the horizontal axis. It is a thing. Further, FIG. 1 shows conditions (profiles) for capacitor-type welding and inverter-type welding in the respective states of FIG. 1 (a) and FIG. 1 (b).

  As can be seen from FIG. 1 (a), since the temperature rise cannot be controlled by capacitor welding, the temperature drops after reaching the maximum temperature along the temperature rise at that time. On the other hand, in the case of the inverter type, it can be seen that the frequency related to the temperature control is controlled by the inverter so that the maximum temperature can be set freely so that the desired temperature is obtained.

  Further, from the graph of the energization time until the welding temperature shown in FIG. 1 (b) is reached, a graph comparing capacitor type welding and inverter type welding as in FIG. 1 (a) is shown. Since the temperature rise cannot be controlled with capacitor type welding, the temperature drops after reaching the maximum temperature along the temperature rise at that time, whereas in the case of the inverter type, around the maximum temperature By controlling the temperature at, the occurrence of a sudden temperature change at the maximum temperature is suppressed.

  In addition, in the graph of FIG. 1B, a high temperature range that causes splash and a temperature range that causes nugget are shown in the graph. However, in capacitor type welding, splash is generated. It can be seen that the maximum temperature reaches the temperature range in which inverter welding is controlled at a temperature below the temperature range in which splash is generated.

  In addition, inverter welding maintains a temperature that is above the temperature range where nuggets are generated, so the temperature is set to eliminate both splash and nugget generation. Here, the nugget indicates a welding unevenness that is warped at the welded portion when welding the base of the metal container and the lid, and indicates that the welding of the nugget portion is in an unstable state. Therefore, this nugget location may have weak welding strength or may have an unwelded location in some cases.

  From the above, the present inventor has an inverter type welding in order to adjust the amount of metal components scattered during welding when the base portion and the lid portion which are metal containers are welded by resistance welding. In this case, the best welding conditions were experimentally obtained by solving various problems (insufficient joint strength, missing joints, etc.) that occurred during sealing.

  As a result, the penetration of contaminants into the container is suppressed and the airtightness and bonding strength of the base and lid are improved. Using welding means for welding by energizing the rectified welding current, the welding time for the inverter type welding in which the frequency is varied by an inverter is set to 5 ms, and the welding time at that time is set to 5 ms. The inventors experimentally obtained welding conditions for inverter welding characterized in that pressurization (force) was 1.45 kN and energization current 10.5 kA was applied for 10 ms.

  In the welding method of the present invention, since the occurrence of slush changes in a Log manner, depending on the base material of the metal base lid, it may be possible to control with current, time, and pressure. However, compared to capacitor type welding, inverter type welding can widen the setting range of sealing conditions and can easily set conditions. As a result, the degree of sealing by welding in which the projection part is stably crushed also increases.

  In addition, the figure shown in FIG. 3 shows the welding state with respect to the setting time until it reaches welding temperature, and the setting time. In the present invention, the inventor has been able to find the optimum setting time by experiment, and concludes that welding is sufficiently possible if the setting time until reaching the welding temperature is 5 ± 1 ms. However, since the nugget state may occur in the case of 4 ms, 5 ms is ideally set as the set time.

  The entire energization time may of course be 10 ms or longer. However, since the time required for welding is 10 ms, the additional manufacturing time is wasted. If it takes 10 ms extra time, it takes about 10 000 ms when 1000 welding operations are performed. Therefore, as the mass production quantity increases, the manufacturing time is wasted. Therefore, the inventor sets the time required for welding as 10 ms as the shortest time for obtaining the best welding result.

In the graph showing the state of the present invention, FIG. 1 (a) shows the welding current-time, and FIG. 2 (b) shows the temperature-energization time. It is the figure which showed the concept of the welding state. It shows the relationship between the set time to reach the welding temperature and the welding state.

Claims (2)

Welding of the inverter type welding in which welding is performed by energizing a welding current obtained by rectifying a current having a frequency higher than the power supply frequency, and the high frequency of the work is clamped between welding electrodes. In the method
A welding method for inverter welding, characterized in that a set time until reaching a predetermined welding temperature is set to 5 ms. 2. The welding method of inverter type welding according to claim 1, wherein the welding conditions at a predetermined temperature are a pressurization (force) of 1.45 kN and an energization current of 10.5 kA for 10 ms.

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