Fraunhofer ILT Debuting New Process that Combines Welding, 3D Printing, and Robotics

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How often do you combine welding, 3D printing, and robotics? We typically see variations of two of these three things paired together, but not often all three in the same project. This November, the Fraunhofer Institute for Laser Technology ILT will be presenting at the electronics development and production productronica trade fair in Munich, showcasing its Laser-Based Tape-Automated Bonding technology, or LaserTAB for short, that does combine all three.

According to a paper published in Electronics Packaging Forum, titled “An Introduction to Tape Automated Bonding Technology,” a Tape Automated Bonding (TAB) assembly generally consists of a silicon chip, copper beam leads, and a circuit board.

The lightweight construction robot “iiwa” guarantees that man and machine cooperate smoothly. [Image: KUKA AG]

Researchers from Fraunhofer ILT, which is located in Aachen, Germany, will be demonstrating how to micro-weld power electronics and new battery cells together in a more precise, efficient manner, thanks to an innovative combination of new optics and robotic support. The team developed the LaserTAB process itself, which uses a laser scanner and process monitoring, along with the new optics and robotics – specifically a lightweight robot (the German acronym is LBR) developed by KUKA Robotics, which is well known for its advanced robotic technology.

Just like KUKA’s bartender robot, this LBR is also an ‘intelligent industrial work assistant,’ or iiwa, and is the first sensitive robot manufactured in series; it will also help humans collaborate closely with robots.

In order to give the collaborating robot, or Cobot, optical distance, the researchers mounted a relay-optic and a spacer on it. The spacer makes sure that the optics comply with the focal length, or distance, that’s necessary for the process to work. The KUKA LBR iiwa is actually able to feel when the spacer touches the weld, and will then begin the welding process. The sensing LBR iiwa and the spacer hold the welding points at a constant distance from the lens.

Battery modules from 18650-battery cells contacted by laser-beam microwelding. This module was developed in collaboration with the Fraunhofer Institute for Structural Durability and System Reliability LBF in Darmstadt as part of the project evTrailer. [Image: Fraunhofer ILT]

At the upcoming trade fair, Fraunhofer ILT will use concrete applications to show how the LBR will make the microjoining process used in battery technology more reliable and precise. The researchers will combine both the 3D printing and microjoining processes, both of which can use this welding process, in a demonstration of how to better weld prismatic, round and pouch cells.

Optimized LaserTAB for Welding of Battery Cells [Image: Fraunhofer ILT]

The researchers will use a technology demonstrator to show how the LaserTAB process can be used to connect a round cell with a copper contact element; additionally, they developed a specially-shaped copper connector using an SLM 3D printing process.

There are several advantages to the precise robot-assisted LaserTAB process, particularly when it comes to complex situations and geometry. The user directly guides the robot to the point of use, eliminating any complicated positioning – no more searching for the proper focus position, or moving the laser around. The spacer helps with positioning as well, negating clamping devices, as it ensures that the connector is pressed against either the battery or the workpiece, and makes sure that the focus position does not change during joining.

The system mechanically controls the distance of the new optics to the actual welding site, which will be very helpful for users when they need to balance multiple heights or production tolerances.

If you’re in Munich next month for the productronica trade fair, you can learn more about the unique LaserTAB process at the Fraunhofer ILT stand B2.317.

Discuss this and other 3D printing topics at 3DPrintBoard.com, or share your thoughts in the comments below. 

[Source: Fraunhofer ILT]

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