Liquid storage multi-station automatic flame brazing machine
January 29, 2024
Abstract: The rotary multi-station automatic flame brazing machine is researched and developed, which is suitable for large-volume brazing production of compressor accumulators. Brazing can also be used for different types of workpieces by changing different fixtures. The brazing machine is controlled by PLC and is equipped with a gas flow/pressure closed loop feedback control system and a human-machine interface system. The process parameters can be easily set and modified, the flame intensity is stable, and the brazing quality is excellent.
Keywords: multi-station brazing machine flame brazing reservoir
0 Preface
In the production of compressor components of air conditioners, many components such as the connection of the reservoir tank to the copper pipe require a brazing process. The market demand for air conditioners is expanding day by day, and higher requirements are also imposed on their brazing equipment and related processes. The introduced multi-station automatic flame brazing machine is developed for the above requirements and has been stably used for brazing production of many related companies.
1 Overview of design ideas
The structure of the brazing machine is “eight-station turntable”. In order to meet the needs of welding different kinds of workpieces, the main machine is designed to be universal. When welding different products, the fixture of the corresponding workpiece can be matched.
The closed-loop feedback control of the flow and pressure of the gas and oxygen in the gas path system ensures that the gas output of the torch nozzle is constant, that is, the heating energy is stable, thereby ensuring the stability of the product quality.
The special plane is equipped with air-cooled and water-cooled systems, which can be used as needed.
2 workpiece to be welded - description of the reservoir
Reservoirs are generally classified into two broad categories based on their structure. One is a combination of a casing and a bent pipe, and the other is a combination of a pipe or a Z-tube (Fig. 1).
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Figure 1 reservoir parts diagram
The copper tube extends into the assembly of the housing, and the coaxiality between the copper tube and the housing is relatively high, which puts high requirements on the design of the fixture, and the installation is convenient and the positioning accuracy is ensured.
3 Brazing machine composition
The brazing machine consists of three parts: mechanical system, automatic control system and welding system. The schematic layout of the equipment is shown in Figure 2. As can be seen from the figure, the brazing machine has the following eight stations: 1 station: upper station; 2 station: inspection (with or without workpiece) station; 3 station: preheating (connection tube and housing) Position; 4 workpiece: welding station; 5 station: air-cooling station; 6 station: water-cooling station; 7, 8 station: unloading station.
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Figure 2 Plan layout of 8 station automatic brazing machine
3.1 Mechanical system
The mechanical system mainly includes an indexing mechanism, a workpiece fixture, a heating device, a feeding device, and the like.
3.1.1 Indexing mechanism The indexing mechanism is an imported intermittent splitter. The indexing process is balanced, has no inertial impact, and is positioned accurately. There are a total of eight stations, and each type of positioning fixture can be installed in each station.
3.1.2 Heating device The heating device has a swing function, which can drive the flame nozzle to swing. The swing speed and swing amplitude and the dwell time of the swing to both ends are steplessly adjustable, which can meet the heating requirements of different workpieces.
3.1.3 The feeding device uses a disc-shaped solder wire for brazing filler wire, and the brazing material feeding process is stable and is not affected by the change of the diameter of the brazing material. The feeding speed and feeding time of the brazing material can be adjusted arbitrarily, that is, the feeding length is steplessly adjustable.
3.2 Electrical Control System The control system is centered on PLC and equipped with a color human-machine interface to achieve automatic control and monitoring of the welding process. The control system specifically realizes the turntable indexing control, the oxygen and gas proportional valve opening degree control, the welding torch swing control, the solder feed control, and the detection and alarm control.
3.3 Welding system The welding machine uses an oxygen-gas (propane or liquefied petroleum gas) system for flame brazing. Therefore, the welding system includes a two-way gas system of oxygen and gas. Each system is equipped with a pressure switch, flow / pressure controller, proportional valve, sensor and so on.
The welding system is provided with a liquid flux supply system, and the flux can be applied by a gas flame, and the effect is good, and the fluxing process is omitted.
4 Main functions and characteristics of brazing machine
4.1 Workpiece inspection The brazing machine table is equipped with a "workpiece presence or absence" detection device. When there is no workpiece on a fixture, when the fixture is transferred to the corresponding station, the actuator of the station (swing heating, brazing) Feeding, etc.) do not operate to avoid empty burning fixtures and feed empty welding.
4.2 Gas pressure detection When the oxygen or gas pressure supplied to the brazing machine is insufficient, an alarm can be given; when the pressure of the nitrogen gas on the back of the workpiece is insufficient, the alarm prompts and stops.
4.3 Nitrogen-filled protection The brazing machine is equipped with a rotary air guiding system. The clamp on the rotary table can pass nitrogen to protect the inside of the workpiece to be welded, so that it is not oxidized during the brazing heating process.
4.4 Workpiece Cooling The brazing machine is equipped with two sets of cooling mechanisms, which are air-cooled and water-cooled. The cooling time can be easily set and adjusted through the "Parameter Modification" screen in the display unit.
4.5 Man-machine interface brazing machine is equipped with man-machine interface, connected with PLC to realize operation status monitoring and parameter modification; and provides manual control panel for adjustment and maintenance, a total of six types of seven screens.
4.6 Gas Flow Control The brazing machine uses oxygen/gas flow and pressure closed-loop feedback control. The required gas pressure, ie a certain flow rate, can be set as required. When the gas pressure and other factors fluctuate, the opening degree of the proportional valve is adjusted by the sensing signal, thereby ensuring a constant gas flow at the torch nozzle and ensuring the welding quality.
4.7 "Large and small fire" setting Brazing machine can be set to "fire" or "small fire" (ie strong flame or weak flame) according to requirements during the running procedure. In this way, when the welding torch advances into position for heating work, the flame is a large fire required for brazing heating; when the welding torch is returned to wait (during the rotary indexing process), the flame is a small fire, that is, the flame does not extinguish and the gas is saved and reduced. Cost of production.
4.8 "Three-color lamp" indicates that the brazing machine is equipped with "three-color indicator light", the macro display device is in the state: red light - stop state; yellow light - standby (ready to weld) state; green light - operating state.
5 Conclusion
(1) The brazing machine is actually a general-purpose multi-station flame brazing machine, and different workpieces can be brazed by replacing different jigs;
(2) Gas flow, pressure and closed-loop feedback control provide favorable conditions for stabilizing flame strength and ensuring welding quality;
(3) The program control of "large and small fire" makes the brazing machine have the characteristics of low running cost on the basis of excellent brazing quality;
(4) This brazing machine is suitable for large-volume continuous brazing production of steel, copper, aluminum and other materials.
