Robotic Drilling using Laser Tracker Technology

It seems that more manufacturing tasks today are being assisted by robots. Whether it’s out of convenience, safety, or cost, there’s no question that the technology keeps improving. But the one missing piece is that these robots are not yet “intelligent”. They need assistance from software and other hardware to make them accurate and repeatable.

Let’s explore an example of metrology hardware used along with robotic technology:

Variation Reduction Solutions, Inc. (VRSI) has been providing customers with state-of-the-art vision solutions for metrology, industrial robot guidance, and contract inspection services since 1998. The VRSI team consists of the most experienced vision, robot guidance, and metrology specialists in the world to provide customers with expert services and unbiased technology evaluations.

VRSI is the prime contractor on two ongoing SBIR programs administered by the Air Force Research Laboratory (AFRL) and recently completed a third, known as Inlet Duct Robotic Drilling (IDRD). IDRD is now moving to the production stage and involves metrology-guided robotic drilling on key components of military aircraft.

What was the challenge?
IDRD required VRSI and its partners to guide a robotic drilling system that drills and countersinks holes into a military aero structure. The traditional method of drilling these structures required operators to manually crawl into the duct with hand drills and templates. This process was slow, ergonomically challenging, and lacked in-process verification of hole accuracy.

What was the solution?
VRSI and its partners knew they could perform this job more quickly and efficiently using off-the-shelf robots with external guidance, and so they evaluated several technologies and decided on a Laser Tracker. The Laser Tracker is the ultimate solution for VRSI since it is small enough to fit in the duct, yet achieves extremely high accuracy.

How does it work?
The Laser Tracker is used to correct the drilling robot’s position to a radial tolerance of less than two thousandths of an inch. After the drilling sequence is completed, the Laser Tracker is again used to guide a robot mounted inspection device to the proper location to inspect the drilled and countersunk holes. The Laser Tracker’s attributes – size, portability, stability, repeatability, traceability, and accuracy – are benefits that VRSI has seen over traditional methods. Leveraging the efficiency of the latest off-line robot programming methods, the Laser Tracker is used to guide the drilling of over 5,000 holes in the operation.

What was the result?
“A single automated cell replaces several individual, manual cells, and reduces the time to build from weeks to days. We can safely speculate that we are saving millions of dollars over the course of the program with IDRD.” – Don Manfredi, Chief Operating Officer, VRSI