RU2599065C1 - Installation of low-temperature soldering in liquid heat carrier - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention can be used in low-temperature soldering in liquid heat carrier parts soft solders, particularly frames for housings of microassemblies of microwave range. Each of two baths of the device is made in the form of cube and is arranged in the housing with heat insulation. Heating devices are arranged: one is on the rear wall and other is on the front wall of each chamber and two are at the bottom. On side walls of chamber of bath for preliminary heating of parts there are atomisers for supply of nitrogen in it. In soldering bath chamber there is liquid heat carrier. Chambers are arranged in the housing of the plant, closed tight top cover with illumination. Front wall of the housing is transparent to displace vertically. Pipe is attached to condensation device, this pipe is connected to ventilation via flange and is closed with coolant condensate collector reservoir connected with chamber soldering via bend.

EFFECT: technical result is improvement of quality and as a result, reliability of connection of parts that provides higher yield.

1 cl, 1 dwg

Description

The invention can be used for low-temperature soldering in a liquid coolant parts with soft solders. The installation provides high performance soldering frames for cases of microassemblies of the microwave range.

Known installation for low-temperature soldering in the vapor phase. The design consists of three chambers. Each of the chambers is filled with vapors of a neutral liquid, which is heated at the bottom of the chamber by corresponding heaters. Soldering heating can be carried out using various heat sources. The soldering process is carried out at a constant temperature in a non-oxidizing atmosphere [1]. The disadvantages of this installation are:

- the difficulty of sealing the installation;

- high power consumption;

- the impossibility of soldering bulk products, the installation is used for soldering printed circuit boards.

A known installation for soldering parts with soft solders in a liquid coolant, adopted as a prototype [2].

The installation has two bathtubs, each bathtub is equipped with an individual heater and a temperature regulator to control the temperature of the coolant. Loading the mandrel into the bath, removing the mandrel from it, moving from the bath to the bath, opening and closing the baths with lids is mechanized. Exhaust ventilation is provided in the installation, and a special device is made for the condensation of vapors in the form of two tubular radiators cooled by water.

The disadvantages of the device are:

- the possibility of thermal shock when lowering the mandrel in the hot coolant or when lowering the hot mandrel in the cold coolant;

- the possibility of partial oxidation of soldered surfaces.

The technical result of the invention is to improve the quality of soldering and, as a result, the reliability of the connection of parts, which provides an increase in the percentage of yield of suitable products.

The technical result is achieved by the fact that the installation of low-temperature soldering in a liquid coolant contains a body with exhaust ventilation, in which two baths with heating, temperature control and regulation devices, a condensation device and a movement mechanism are installed. The bathtubs are installed in a sealed enclosure, each bathtub is a cube-shaped chamber placed in a casing with thermal insulation, and is closed by a cover with the possibility of rotation, while the heating devices made in the form of heating elements are located one on the rear and front walls of the chamber and two at the bottom, a temperature meter is placed inside the chamber, nozzles are located on the side walls of the chamber of the first preheating bath, and a hole for supplying nitrogen is made in the rear wall of the casing, liquid is poured into the chamber of the second bath heat carrier, the installation case is closed with a sealed top cover with backlight, and the front wall is transparent with the ability to move vertically, the condensation device is a box located above the bathtubs and extending outside the body to which a pipe is attached, connected through the flange to the side to the ventilation and closed a container for collecting coolant condensate, which is connected to the soldering chamber by a tap, while the pipe walls are hollow and have ribs on the inside, the movement mechanism is made in the form telpher.

The backlight can be made in the form of fluorescent lamps.

The bathtubs are installed in a sealed enclosure, which allows you to create a nitrogen atmosphere in it that prevents oxidation of the surfaces of the soldered parts, which increases the quality of the solder and the reliability of the connection.

Each bath is a cube-shaped chamber, placed in a casing with thermal insulation, and closed with a lid with the possibility of rotation, which allows to reduce the heating time of the solder and reduce heat dissipation by one and a half times. A sealed lid creates a closed volume that speeds up heating.

The heating devices, made in the form of heating elements and located one at a time on the outside of the chamber on the back and front walls and two on the bottom, ensure efficient heating of the chambers.

On the side walls of the chamber of the preheating bath, nozzles are located through which nitrogen enters the chamber, which ensures uniform heating and slow cooling of the mandrel with soldered parts, and therefore eliminates the possibility of thermal shock and warping of parts.

In the rear wall of the casing of the preheating bath, a hole is made for supplying nitrogen from the network to the space between the casing with thermal insulation and the chamber, where the nitrogen is effectively heated.

The installation case is closed by a sealed top cover with backlight, and the front wall is transparent with the ability to move vertically, which ensures ease of operation and monitoring of the process.

The condensation device is a box located above the bathtubs and extending beyond the housing to which a pipe is attached, connected through a flange to the side of the ventilation. A contaminated mixture of nitrogen and air exits the enclosure.

The condensation device pipe is closed by a tank for collecting condensate of the coolant. The tank is connected to the soldering chamber by a tap to drain the condensed coolant, eliminating its loss.

The walls of the pipe are hollow and have ribs inside. Passing cold water in the cavity of the walls and due to the ribs, coolant vapors are more efficiently cooled.

The movement mechanism is made in the form of a hoist, controlled and moved along the guide from one bath to another.

The installation of low temperature brazing in a liquid coolant is illustrated in FIG. one.

In FIG. 1 shows the proposed installation of low-temperature soldering in a liquid coolant, where

tight case - 1,

preheating bath - 2,

soldering bath - 3,

preheating bath chamber - 4,

soldering bath chamber - 5,

a casing with thermal insulation of the preheating bath - 6,

casing with thermal insulation of the soldering bath - 7,

preheat bath lid - 8,

soldering bath cover - 9,

temperature meter - 10,

TEN - 11,

nozzle - 12,

nitrogen supply hole - 13,

coolant - 14,

case cover - 15,

backlight - 16,

the front wall of the housing - 17,

condensation device - 18,

box - 19,

pipe with hollow walls and ribs - 20,

flange - 21,

condensate collection tank - 22,

branch - 23

movement mechanism - 24.

Example

Preheating bath 2 and soldering bath 3 are installed on the countertop in an airtight casing 1 made of sheet steel 10 with a thickness of 1.5 mm. The housing 1 has a top cover 15 with a backlight 16 made by two fluorescent lamps, the front wall 17 is transparent from TOSN plexiglass 8 mm thick. The front wall 17 is moved up and down using a roller mechanism.

Above the bathtubs a box 19 is installed, made of sheet steel 10 with a thickness of 2 mm, and a movement mechanism 24 in the form of an electric hoist. The hoist moves along the steel rail in the form of a channel.

Both baths 2 or 3 have a chamber 4 or 5 made of sheet steel 12X18H10T with a thickness of 3 mm in the form of a cube with a size of 500 × 500 × 500 mm.

Each chamber 4 or 5 is installed in a casing 6 or 7, made of sheet steel 12X18H10T with a thickness of 1.5 mm, with thermal insulation from cardboard of asbestos KAON-1 with a thickness of 8 mm. Between the chamber 4 and the thermal insulation of the casing 6 there are heaters of the heating elements 11. One at the rear and front walls of the chamber 4 and two at the bottom of the chamber 4. The heating elements 11 have a U-shape and a power of 1 kW. The same thing between the camera 5 and the casing 7.

On the walls of the chamber 4 there are 8 nozzles 12 with a through hole of 3 mm diameter. On the rear wall of the chamber 4 there is a hole 13 with a diameter of 6 mm for supplying nitrogen.

In the chamber 5 is filled with a coolant 14 glycerin with an activator. Box 19 is part of a vapor condensation device 18; outside the housing 1, it is connected to a pipe 22 having hollow walls and ribs on the inner surface. The opposite end of the pipe 20 is closed by a stainless steel container for collecting condensate 22, which is connected via a tap 23 to the bath 5. Through the flange 21, the pipe 20 is connected to exhaust ventilation.

Installation of low-temperature soldering in a liquid coolant operates as follows.

The soldered parts, between which the POS 61 solder is laid, are fixed in the mandrel. In the housing 1, the front wall 17 and the cover 8 of the preheating bath 2 and 9 of the soldering bath 3 are open. 3. Using the telpher 24, the mandrel is loaded into the chamber 4 of the bath 2. Liquid coolant 14 (glycerin with additives) is poured into the chamber 5 of the soldering bath 3. Close the lids 8 and 9, lower the wall 17 of the housing 1. Turn on the heating elements 11 and through the hole 13 into the bath 2 let nitrogen. The mandrel in bath 2 is heated to 150 ° C, and the coolant in bath 3 is heated to 270 ° C. Open the lid 8. The mandrel using the hoist 24 is moved and immersed in the chamber 5 of the bath 3. Close the lid 9. Soldering is carried out at a temperature of 230 ° C. The lid 9 is opened and the mandrel is taken out with a hoist 24 and kept above the bath until the coolant drains off and the solder crystallizes. Open the cover 8, and the mandrel is transferred to the chamber 4, into which nitrogen flows from the network through the nozzle 12 through the nozzle 12. The mandrel is cooled with the open cover 8 to 65 ° C. Then the mandrel is removed by a hoist 24 from the chamber 4 and from the installation. In the chamber 5, during the heating of the coolant 14, it is dehydrated at a temperature of 200 ° C for 20-40 minutes, which does not allow oxidation of the brazed surfaces.

At the experimental setup EH2607, soldering of parts of waveguides and other nodes of the antenna device coated with nickel was carried out. Achieved high quality soldering parts.

Productivity has increased one and a half times compared with the installation without preheating. Product yield increased by 50%.

Information sources

1. Japan, Application 63-30172, MKI B23K 3/04, H05K 3/34

2. Korpachev M.G. etc. Flux-free soldering of parts in a liquid coolant. - “Exchange of experience in the radio industry, 1982, issue 1.

Claims (2)

1. Installation for low-temperature soldering in a liquid coolant, comprising a body with exhaust ventilation, in which two bathtubs are installed with heating devices, temperature control and regulation, a device for condensing a coolant and a mechanism for moving parts, characterized in that one bath is designed to preheat parts and the other for soldering, each of them is a cube-shaped chamber placed in a casing with thermal insulation and closed with a lid with the possibility of its rotation, while the device the heating elements are made in the form of electric heating elements and are located one on the rear and front walls of the chambers and two on the bottom, with nozzles for supplying nitrogen to it on the side walls of the preheating bath chamber, an opening for supplying nitrogen is made in the rear wall of the casing of the said chamber In the space between the casing and the chamber, and in the chamber of the soldering bath, liquid coolant is poured, while the said baths are installed in a housing closed by a sealed top cover with backlight, the front wall of which is transparent with by moving it vertically, and the device for condensing the coolant is made in the form of a box located above the bathtubs extending outside the housing, to which a pipe with hollow walls is attached, having ribs on the inner surface, connected laterally through a flange to the ventilation and closed by a condensate collection tank the coolant connected to the soldering chamber by a tap to drain the condensate, and the mechanism for moving parts is made in the form of a hoist. 2. Installation according to claim 1, characterized in that the backlight is made in the form of fluorescent lamps.

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