Application and Analysis of Welding Equipment in Changan Automobile Production Line

October 23, 2018

1 Introduction

Since the production of automobiles in the mid-1980s, Changan Automobile Group has gradually developed a large number of welding production lines from low-end to high-end, from single to multi-variety, from micro-car to self-owned car. With a wide range of high-tech welding equipment, the application range of new technologies in the field of welding is also expanding. After more than 20 years of long-term practice, the unsuitable welding production equipment has been gradually eliminated. Changan and equipment manufacturers have formed long-term strategic cooperation research partners for equipment with mature performance and suitable for welding automobile production lines. The welding equipment is continuously optimized, providing a large number of high-quality products with stable performance, low failure rate and high cost performance for the automotive welding line.

At present, the welding equipment applied by Changan Automobile Group can be roughly divided into four categories: direct welding equipment, tooling fixtures, fastening pressures, and inspection tools. This paper mainly describes and briefly analyzes the use of the above welding equipment in Changan Automobile Group, existing problems, and expected technical upgrades.

2, direct welding equipment

Direct welding equipment refers to welding equipment that uses such equipment to bond workpieces together by welding. At present, the company mainly has the following types of direct welding equipment: hanging spot welding machine, brazing, automatic welding, spot welding robot, Arc welding robot, MIG welding machine, fixed nut projection welding machine, stud welding machine, etc.

â—†Hanging spot welder

Hanging spot welder - The company mainly uses Tianjin High-tech products. The overall performance of the product is quite stable, easy to use and easy to maintain. It is currently the most widely used welding equipment in Changan's automotive welding production line.

Through the cooperation between Changan and the supplier, the supplier developed a group control system for the hanging spot welder based on the suspended spot welder, which is a system for centralized control of the submerged spot welder. The main function of the group control system is to monitor the three-phase voltage in real time, ensure the real-time balance of the grid voltage through the limited capacity control method, and provide direct guarantee for the spot welder in the real-time monitoring system, so that the quality of the welding product is more stable.

Some problems have also occurred in the use of such equipment: mainly the loss of welding process parameters, the occasional direct-through of the thyristor and the self-ignition of the transformer.

â—†å‚€å„¡ welding, automatic welding

Butt welding is a type of welding by means of external artificial welding to parts that are not smooth on the production line and that cannot be welded by ordinary welding tongs. That is, welding is performed on the auxiliary mechanism by the welding tongs, and the auxiliary mechanism is led to the position of the parts to be welded. Thereby completing the welding.

Automatic welding - the automatic control of the welding trajectory and welding parameters of the welding tongs by the programmable controller, so that the welding tongs are automatically welded according to the process specifications.

The two differences between boring and automatic welding are that automatic welding does not require manual operation, and boring requires manual operation. These two welding methods have fewer failures, stable performance and good welding quality, but the quality requirements of the parts (ie, the consistency requirements of the parts) are high. If the accuracy of the parts is not up to the requirements, the welding equipment may be faulty.

At present, programmable controllers have been widely used in automotive welding production lines. The trend is not to use tantalum welding and completely automatic welding, which reduces the manual operation intensity and reduces the operating cost of the enterprise.

â—† spot welding robot, arc welding robot

Spot welding robots - The company currently uses a large number of the world's most typical robots such as COMAU, KUKA, and ABB. Regardless of the type of robot, the robot body has fewer faults, and most equipment failures are caused by the welding tongs and welding controllers installed on the robot arm.

There are two methods of robotic welding tongs control: servo control and pneumatic control. At present, the most used servo control tongs are used. The servo welding tongs have high requirements on the accuracy of the parts. If the accuracy of the parts is not up to standard, the failure rate of the robot servo welding tongs will be very high, and the maintenance cost is high, and the spare parts cost is also high, which is not conducive to the cost saving of the enterprise. The maintenance cost of the pneumatic welding tongs is relatively low, and the maintenance is convenient. The accuracy of the parts relative to the servo welding tongs has a low damage rate to the equipment.

Arc Welding Robots - The company currently uses two Japanese OTC brand robots. The arc welding performance is stable, easy to use and maintain, and it will not be analyzed in detail because there are too few applications.

â—†MIG welder

MIG welding machine - commonly known as carbon dioxide protection welding, the overall performance of this equipment is stable, the failure rate is low, one of the shortcomings is that the torch part of the MIG welding machine is vulnerable. Because the company uses the MIG welding machine supplied by Lincoln of the United States, it belongs to imported equipment and the spare parts are expensive (mainly referred to as welding torch). After Changan technicians research and years of practice, the welding torch spare parts of this welding machine have basically adopted domestic matching, which greatly saves the use cost and maintenance cost.

Another disadvantage of the MIG welder is that the smoke and dust are relatively large during use. The company uses the equipment in the automotive welding production line. At the same time, it is equipped with the exhaust and dust removal equipment produced by the American Donaldson Company to ensure the operators on the production line. Occupational health and work environment are not polluted.

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