This November, the Experts of the Fraunhofer Institute for Laser Technology ILT will be presentinga pioneering novelty at productronica 2015, the world's leading trade fair for electronics development and production.They are focusing on a totally new laser-based joining technique that will provide plenty of momentum to the electronics production industry.
The five letters stand for a development from Aachen that is meant to inspire specialists from the electronics manufacturing sector: they are talking about another kind of “LIMBO,” the acronym for “Laser Impulse Metal Bonding.”
A 200 µm thick copper ribbon on a PCB joined via the LIMBO process.
© Fraunhofer ILT, Aachen, Germany.
“This laser process expands the process limits of conventional welding and soldering processes considerably," explains Dipl.-Ing. Simon Britten, head of the LIMBO project.
“It opens up completely new fields of applications for the joining of temperature-sensitive components.” Within three years, the researchers have developed a thermal joining process that overcomes the limitations of conventional methods and deposits only a minimum of energy in the components.
This enables the unprecedented joining of components such as thick ribbon interconnectors in power electronics with sensitive, fast-switching chips (e.g. for wind turbines or electric vehicles). In contrast to soldering, the contacts have a high temperature stability and show, in comparison to conventional welding or bonding, a minimal effect on the component.
“Thanks to LIMBO, we can now also thermally join thick ribbons that have a thickness of 200 µm or more with thin metallization layers,” says the expert on micro joining. “The secret is in breaking up the classical welding process into the separate phases of heating and joining.”
In contrast to typical electrical connecting processes, here a relatively large gap is used, in which a thermally isolated weld pool forms. Britten: “We control the process – which lasts a total of less than 20 milliseconds – so that the connection is essentially made solely by the energy in the melt, and not by the laser beam. This leads to a minimal energy input.”
In a process where embossment or isolation material is used to create gaps of more than 50 µm, the LIMBO process can be applied when the metallization layer has a thickness in a two-digit micrometer range. At productronica, Fraunhofer ILT will demonstrate the process using a fiber laser (wavelength: 1070 nm).
“All laser sources that can be modulated in the range of milliseconds to microseconds can be used,” explains the scientist. “What is needed for the short exposure time is a laser power of about two kilowatts, but with the fiber laser around 500 watts are also sufficient.”
Experts will be showing possible applications of LIMBO at the productronica
Now that Fraunhofer ILT has laid the basic groundwork, the project manager and his team are certain how LIMBO works and that it is reliable. “This process can be considered – thanks to its low penetration depth of less than 20 microns – for many applications with heat-sensitive components,” says Britten.
The range of possible applications for LIMBO is very broad: it extends from inserts in control technology for alternative energy (keyword: power electronics for inverters of wind turbines) to electro mobility.
“We are helping prospective customers adapt the process to their applications by means of functional models.” Interested parties can find out more about LIMBO and its potential applications at the productronica in Munich from November 10 to 13 at the Fraunhofer Joint Booth 2017 in Hall B3.
Dipl.-Ing. Simon Britten
Micro Joining Group
Telephone +49 241 8906-322
Dr. Alexander Olowinsky
Head of the Micro Joining Group
Telephone +49 241 8906-491
Fraunhofer Institute for Laser Technology ILT
Petra Nolis | Fraunhofer-Institut für Lasertechnik ILT
Adhesive Process Developed for Shingle Cell Technology
09.01.2019 | Fraunhofer-Institut für Solare Energiesysteme ISE
Seawater turns into freshwater through solar energy: A new low-cost technology
08.01.2019 | Politecnico di Torino
The scientific and political community alike stress the importance of German Antarctic research
Joint Press Release from the BMBF and AWI
The Antarctic is a frigid continent south of the Antarctic Circle, where researchers are the only inhabitants. Despite the hostile conditions, here the Alfred...
World first experiments on sensor that may revolutionise everything from medical devices to unmanned vehicles
The new sensor - capable of detecting vibrations of living cells - may revolutionise everything from medical devices to unmanned vehicles.
Dead and alive at the same time? Researchers at the Max Planck Institute of Quantum Optics have implemented Erwin Schrödinger’s paradoxical gedanken experiment employing an entangled atom-light state.
In 1935 Erwin Schrödinger formulated a thought experiment designed to capture the paradoxical nature of quantum physics. The crucial element of this gedanken...
Cellulose obtained from wood has amazing material properties. Empa researchers are now equipping the biodegradable material with additional functionalities to produce implants for cartilage diseases using 3D printing.
It all starts with an ear. Empa researcher Michael Hausmann removes the object shaped like a human ear from the 3D printer and explains:
The phenomenon of so-called superlubricity is known, but so far the explanation at the atomic level has been missing: for example, how does extremely low friction occur in bearings? Researchers from the Fraunhofer Institutes IWM and IWS jointly deciphered a universal mechanism of superlubricity for certain diamond-like carbon layers in combination with organic lubricants. Based on this knowledge, it is now possible to formulate design rules for supra lubricating layer-lubricant combinations. The results are presented in an article in Nature Communications, volume 10.
One of the most important prerequisites for sustainable and environmentally friendly mobility is minimizing friction. Research and industry have been dedicated...
16.01.2019 | Event News
14.01.2019 | Event News
12.12.2018 | Event News
21.01.2019 | Life Sciences
21.01.2019 | Physics and Astronomy
21.01.2019 | Life Sciences