(1) The position of the weldment must be very precise and must be within the focus range of the laser beam.
(2) When a fixture is required for the weldment, it must be ensured that the final position of the weldment is aligned with the welding point where the laser beam will impact.
(3) The maximum weldable thickness is limited and workpieces with penetration thickness far exceeding 19mm are not suitable for laser welding on the production line.
(4) The weldability of highly reflective and high thermal conductive materials such as aluminum, copper and their alloys will be changed by laser.
(5) When performing medium to high energy laser beam welding, a plasma controller needs to be used to remove the ionized gas around the molten pool to ensure the reappearance of the weld bead.
(6) The energy conversion efficiency is too low, usually less than 10.
(7) The weld bead solidifies quickly, and there may be concerns about porosity and embrittlement.
(8) The equipment is expensive.
In order to eliminate or reduce the defects of laser welding and better apply this excellent welding method, some hybrid welding processes using other heat sources and lasers have been proposed, mainly including laser and arc, laser and plasma. Arc, laser and induction heat source hybrid welding, dual laser beam welding and multi-beam laser welding, etc.
In addition, various auxiliary process measures have been proposed, such as laser filler wire welding (can be subdivided into cold wire welding and hot wire welding), external magnetic field-assisted enhanced laser welding, and shielding gas controlled molten pool depth laser welding, laser-assisted friction stir welding, etc.
Extended information
Laser welding machine technology is widely used in high-precision manufacturing fields such as automobiles, ships, aircraft, high-speed rail, etc., which has brought significant improvements to people's quality of life. Leading the home appliance industry into the era of precision work.
1. Manufacturing application.
Tailored Bland Laser Welding technology has been widely used in foreign car manufacturing. According to statistics, there were more than 100 tailor-welded blank blank laser welding production lines worldwide in 2000, with an annual output of tailor-welded blanks for car components. 70 million pieces of boards, and continues to grow at a high rate.
2. Powder metallurgy field.
With the continuous development of science and technology, many industrial technologies have special requirements for materials, and materials manufactured by smelting and casting methods can no longer meet the needs.
Due to the special properties and manufacturing advantages of powder metallurgy materials, they are replacing traditional smelting materials in certain fields such as automobiles, aircrafts, and tool and cutting tool manufacturing industries. With the increasing development of powder metallurgy materials, The problem of its connection with other parts has become increasingly prominent, which limits the application of powder metallurgy materials.
3. Automobile industry.
In the late 1980s, kilowatt-class lasers were successfully used in industrial production. Nowadays, laser welding production lines have appeared on a large scale in the automobile manufacturing industry, becoming one of the outstanding achievements of the automobile manufacturing industry.
Italy's Fiat uses laser welding in the welding and assembly of most steel plate components. Japan's Nissan, Honda and Toyota Motor Corporation all use laser welding and cutting processes in the manufacture of body panels. High-strength steel laser Welded assemblies are increasingly used in automobile body manufacturing due to their excellent performance. According to U.S. metal market statistics, by the end of 2002, the consumption of laser welded steel structures will reach 70,000 tons, three times more than in 1998.
Baidu Encyclopedia-Laser Welding Technology