CN102941411A - Method for air-tightly welding shell and cover plate of microwave component - Google Patents

Abstract

The invention discloses a method for air-tightly welding a shell and a cover plate of a microwave component. Laser seal welding is adopted; a limited type overlapping structure is used as a joint form for air-tightly welding the shell and the cover plate of the microwave component; a magnetic fixture is adopted during performing seal welding in a glove box full of Ar; and a magnetic base of the magnetic fixture and a press block are attracted by each other. The method disclosed by the invention has the advantages of high air-tightness, small welding heat affected zone, flexible track, no contact in the machining process, environment friendliness and so on and is applied to airtight packaging process of the microwave component shells of various products; and laser seal welding with very high air-tightness is achieved.

Description

The method of microwave components housing and the airtight soldering and sealing of cover plate

Technical field

The present invention relates to technical field of electronic equipment, be specifically related to a kind of microwave components housing that seals by the method for laser weld and the airtight soldering and sealing of cover plate.

Background technology

Microwave components is as important electronic equipment assembly, thereby the process means that adopts during to level Hermetic Package has more restriction: the inside cavity temperature can not surpass the maximum temperature that chip or scolder can bear during (1) sealing, to avoid chip to damage or the solder joint fusing; (2) when sealing can not toxic gaseous volatilization, is preferably in the protective atmosphere and carries out, and will guarantee the cleaning of environment in the housing after the sealing; (3) weld strength to be guaranteed after the sealing, the internal force of a negative pressure can be born at least.

Because the Laser seal welding technology not only can satisfy above primary condition, also have other advantages such as welding track is flexible, air-tightness is high, the heat affected area is little, process is contactless, the application in the level Hermetic Package of microwave components housing is promoted for the Laser seal welding technology thus.

Laser weld is that high-intensity laser beam directly is radiated to material surface, makes the material local melting realize welding.In the Reciprocity of Laser ﹠ Materials process, the variation of reflection of light, absorption, heat conduction and other physics and chemistry can appear.

In the relevant documents and materials of laser welding technology of great majority, all the theory of laser weld elaborated, comprise the technological parameter that affects laser weld such as the power density, impulse waveform, defocusing amount, protective gas etc. have been done theory analysis.

Along with the fast development of modern radar technology, more and more higher requirement has been proposed for the miniaturization of microwave components.In order to adapt to this requirement, the MCM multichip modules technology is arisen at the historic moment, because this technology is directly used bare chip encapsulation, so strengthened the difficulty of technique and to the requirement of reliability.Owing to have a large amount of steam, salt fog etc. in the air, if these particulates enter into component internal, meeting open circuit potential solder joint reduces circuit performance, or circuit module was lost efficacy.So, must carry out level Hermetic Package to the microwave components that adopts the assembling of MCM multi-chip.

Summary of the invention

Problem to be solved by this invention is that the air-tightness of microwave components requires to reach leak rate 1 * 10 on the space product according to the GJB548A regulation ^-8Pam ³/ s.Be convenient to assembling for thousands of assembly, array is neat, high conformity, and the present invention proposes a kind of method this method that seals microwave components Al-alloy casing and the airtight soldering and sealing of cover plate and adopts special fixture, and laser welding technology is finished.

The present invention is by optimizing shell structure and weld jig; realized the airtight soldering and sealing of Laser seal welding microwave components Al-alloy casing and cover plate; with respect to prior art; the present invention effectively raises airtight qualification rate; reduced production cost; can be implemented in level Hermetic Package microwave components under the protective atmosphere, improve reliability and the life-span of microwave components.

Description of drawings

Fig. 1 is the little package assembly schematic diagram of microwave components

Fig. 2 is the structural representation of three kinds of welding points

Fig. 3 is the laser weld timing chart

Fig. 4 is the structural representation of magnetic clamp

The accompanying drawing sign: a is lap joint; B is limit-type lap joint; C is banjo fixing butt jointing

The specific embodiment

Invention provides a kind of sealing microwave components Al-alloy casing for the technical scheme that solves its technical problem and adopt, its innovative point is, adopt Laser seal welding, and select limit-type bridging arrangement as the joint form of microwave components housing and the airtight soldering and sealing of cover plate, in being full of the glove box of Ar, carry out seal welding, adopt magnetic clamp when welding, magnetic bases and the briquetting of this magnetic clamp attract each other.

Below in conjunction with the drawings and specific embodiments, further set forth the present invention.

The structure that is as shown in Figure 1 microwave components forms; general microwave components shell shape all is square chest shape; by housing; inner microcircuit; protective gas and cover plate form in the chamber; also be useful on the bead of signal input and output; be used for the socket that power supply is supplied with; sealing between these connectors and housing generally uses solder to seal before the microwave components assembling; and for Assurance component air-tightness and reliability; the sealing of microwave components housing and cover plate; the part of most critical is exactly the joint of welding; machinability; reprocess operability, stress release; air-tightness; mechanical strength.Rule of thumb and consult related data, as shown in Figure 2 the less joint design of three kinds of thermal stress obtain by experiment selecting (a) although the group handling ease, operation easier is large in the glove box, shell and cover plate are difficult to aim at, so airtight disqualification rate is very high; (c) the airtight qualification rate of group structure is higher than (a) group, but the machined of housing is required too high, and it is also very difficult to uncap when reprocessing; (b) the limit-type bridging arrangement of group in qualification rate, machinability, operability with reprocess the aspect such as complexity, have comprehensive advantage, and leak rate satisfies the GJB requirement.So select (b) limit-type bridging arrangement as the joint form of microwave components housing and the airtight soldering and sealing of cover plate.

The present invention adopts domestic Han ' Laser PB300 type laser-beam welding machine, the metal that easily cracks for aluminium alloy etc., adopt three stage laser pulse wave modes as shown in Figure 3, thereby make the change procedure of welded piece experience preheating → melting → insulation, the quality of welding spot that then can comparatively be satisfied with such as Fig. 2 (b).Adopt negative out of focus 2mm, welding energy 12.56J, the weld melting is soaked into, the surfacing light, welding effect is better

For the requirement of Assurance component internal atmosphere, all component seal weld is all carried out in being full of the glove box of Ar.The glove box gloves are more thick and heavy, operation inconvenience.Therefore, adopt magnetic clamp when welding, magnetic bases and the briquetting of this magnetic clamp attract each other.

These anchor clamps can not block the laser stroke when (1) automatic welding; (2) anchor clamps can be given the pressure of cover plate 〉=2kg, and uniform force application; (3) dress is convenient with download component in glove box.

Adopt magnetic clamp as shown in Figure 4, magnetic bases and briquetting attract each other, and these anchor clamps are shell fixedly, and can effectively reduce thermal deformation in welding process.After tested, briquetting can be given the pressure of cover plate 2～3kg, has avoided the segmentation welding, has improved welding quality.

Its welding process is as follows:

Step 1, cover plate flatness check that the welding edge cleannes check;

Step 2, cover plate and shell overlap the edge structure matching, and carry out little finishing with instruments such as scalpels;

Step 3 is put into magnetic clamp with the shell and the cover plate that match, and is pressed briquetting;

Step 4 by welding equipment editor welding track, is set welding condition;

Step 5, laser weld;

Step 6 is taken out workpiece.

Claims (2)

1. the method for a microwave components housing and the airtight soldering and sealing of cover plate, adopt Laser seal welding, and select limit-type bridging arrangement as the joint form of microwave components housing and the airtight soldering and sealing of cover plate, and in being full of the glove box of Ar, to carry out, the component internal after the sealing is the Ar environment.It is characterized in that cover plate and shell edge adopt the limit-type bridging arrangement shown in Fig. 2 (b), in order to obtain better welding effect, side edge thereof is than shell mural margin indentation 200～300um.

Its welding process is as follows:

Step 1, cover plate flatness check that the welding edge cleannes check;

Step 2, cover plate and shell overlap the edge structure matching, and carry out little finishing with instruments such as scalpels;

Step 3 is put into magnetic clamp with the shell and the cover plate that match, and is pressed briquetting;

Step 4 by welding equipment editor welding track, is set welding condition;

Step 5, laser weld;

Step 6 is taken out workpiece.

2. a method that seals the microwave components Al-alloy casing is characterized in that, magnetic bases and the briquetting of magnetic clamp attract each other.

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