High quality laser beam welding of light weight aluminium die cast materialThursday (09.11.2017) 11:35 - 11:55 Part of:
A light weight application does not only require a material of low density it involves also a combination of their processing and their technology to reach specific properties for their use. Especially for automotive components the sum of aspects is important for example to apply to future CO2 emissions regulations. To provide light weight components for mass production, thin walled cross sections of complex structural parts for instance die cast products can be one reasonable approach.
Currently those products are designed and produced normally leaving joining aspects out of focus. Properties such as pressure tightness of the weld seam in medium flow through systems, likewise cooling or air conditioning systems have to accomplish high quality regulations. Furthermore joining techniques have to be highly productive to obtain high component outcome and they also need to be cost-efficient. Laser beam welding techniques are especially predestinated for those tasks.
State of the art for die cast components is, that they have limited or no weldability due to their manufacturing process. Reasons for that are entrapped gases within pores or cavities under high pressure conditions. Furthermore, the mold release agents for the die cast process are inappropriate for obtaining homogeneous and sound weld seams. Consequently high amount of pores in the weld seam and stochastic melt pool blow outs occur, which prohibit the use of the component.
To solve the addressed issues a new welding technique, the so called remoweld?T, has been developed at Fraunhofer IWS. The unique method has been extensively tested and transferred to the serial-production. The decisive step was to use laser sources with brilliant beam quality in combination with a high frequent beam oscillation within the melt pool.
Within this paper the technological approach will be presented on several examples of potential light weight applications. With the remoweld?T method homogeneous weld seams with low porosity and a strongly reduced distortion can be obtained. A reproducible joining technique without using filler wire material and a high output for serial production is now available. That approach helps to save weight compared to screwing or bonding technology.