Using a short laser pre-pulse, the contacts are treated to provide 100 per cent good welds for the subsequent infrared welding.
Welded contacts on an IC (TSOP 0.5mm pitch) on a printed circuit board (Ilfa) using a laer pre-pulse and IR laser main pulse.
A newly developed "laser pre-pulse module" can be used to initiate the copper welding process and provide a 100% welding guarantee. The laser is small and inexpensive, the result of process developments at the Laser Zentrum Hannover e.V. (LZH). The pre-pulse is decisive for automating micro-processing, or for connecting surface mounted devices to printed circuit boards.
Copper alloys are often found in electronics, sensors and precision engineering applications. Here, high demands are placed on the heat and mechanical stress resistance of spot welds, and laser micro-welding has very good weld qualities. However, non-ferrous metals are difficult to weld, due to high reflectivity, and a sudden jump in energy absorption when the melting temperature is reached. It is difficult to repeat good welding results, and with low process stability, up to now lasers have only been used following complex surface treatment, or for manual applications.
Researchers at the Department of Production and System Technology at the LZH have developed a new process, which uses a laser pre-pulse with a peak output of no more than 1 MW and a pulse length of only a few nanoseconds to initiate the welding process. This short-pulsed, solid-state, frequency converted laser has a high degree of absorption, and provides stable conditions for the subssequent high-output welding using a conventional IR laser. The welding energy can be easily controlled after pre-pulsing.
Experiments using the pre-pulse prototype of the company neoLASE were carried out on an 80 µm thick, 2mm wide copper band. After 200 repetitions, the welding results were constant, implying that the welds were 100% good. "This result is already a great success," says engineer Anas Moalem, who is responsible for the development of the process. Apart from improved precision and quality, the process window for the laser parameters could be expanded considerably.Depending on the weld spot diameter, the laser output power could be reduced by up to 40%, meaning that using the compact pre-pulse module (13 x 9 x 4 cm) could result in energy savings in the kilowatt range for the IR welding lasers.
Developments took place within the framework of the SME-innovation project "Supreme", which was financed by the BMBF (German Federal Ministry of Education and Research) under supervision of the PTKA-Project Management Agency Karlsruhe. Support was also given by the companies Arteos GmbH, Ilfa GmbH, neoLASE GmbH and Sill Optics GmbH & Co. KG.Contact:
Michael Botts | LZH
Innovative process for environmentally friendly manure treatment comes onto the market
03.05.2018 | Fraunhofer-Institut für Grenzflächen- und Bioverfahrenstechnik IGB
No compromises: Combining the benefits of 3D printing and casting
23.03.2018 | Fraunhofer-Institut für Produktionstechnik und Automatisierung IPA
The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.
Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...
A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.
The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...
At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.
At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...
There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?
At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
25.05.2018 | Event News
02.05.2018 | Event News
13.04.2018 | Event News
25.05.2018 | Event News
25.05.2018 | Machine Engineering
25.05.2018 | Life Sciences