The R-Drill 200 from Raydiance is a laser-based micro hole drilling solution suitable for fuel-injector manufacturers, including those that produce gasoline direct injection (GDI) spray nozzles. The Petaluma, CA-based company says the technology is the result of years of science and engineering innovation (27 patents to date), taking femtosecond laser pulses—pulse duration in the range of a few quadrillionths of a second—and applying it to solve real-world manufacturing challenges. The technology will be showcased in the company’s SAE 2013 World Congress booth (#712P) April 16-18 in Detroit.
With the R-Drill 200 no-touch machining, the laser hits its target so quickly that material is vaporized molecule by molecule, with no heat dissipation. This phenomenon was known to academic scientists for years, according to Dr. Michael Mielke, Chief Scientist at Raydiance, but was not previously available to industry due to the cost and complexity of early-generation femtosecond laser systems. In other laser-machining processes, heat causes melting, burring, discoloration, and other thermal effects that must be addressed in post processing.
Raydiance claims to have developed the world’s first industrial-grade femtosecond laser based on a fiber-optic architecture. Parts can be machined to precise specifications, with no chemical or mechanical rework. Greater part consistency—at the scale of 1 micron (39.4 μin)—leads to better performance in the vehicle. For example, GDI spray nozzles made with the R-Drill 200 can deliver precise fuel flow and ideal atomized fuel distribution in the engine cylinder, thereby enabling the 30% better fuel efficiency achievable with GDI without compromising engine output performance.
“The R-Drill 200 addresses the simultaneous challenges of greater machining precision, broader flexibility in feature shape, and more cost-effective means of manufacturing the next generation of fuel injectors,” said Mielke. “The R-Drill 200 can be programmed to drill virtually perfect spray holes in fuel injector nozzles in less than a second per hole. The level of precision in fabricating arbitrary hole profiles is enabling a new generation of fuel injectors to direct spray patterns and droplet size distribution much more accurately to where it is needed for combustion.”
The geometries and surface finishes achieved by the R-Drill 200 were not practical with other fabrication technologies, such as electrical discharge machining (EDM) or mechanical punch. The speed and efficiency of the process reportedly can lower the overall costs of producing the new injectors.
“This innovation is beneficial to [automotive parts manufacturers] because they are able to fabricate better fuel injectors with a process that is faster, cleaner, and much lower cost. These manufacturers are operating under government mandate for fleet-wide vehicle fuel efficiency increases and emissions reduction, and a primary means of achieving the mandate is advancing fuel-injector technology,” Mielke said. “The design selection of GDI injectors for more and more new vehicles is a very visible result of this mandate.”
The realization of this innovation started with the fuel-injector engineers who design GDI and the higher-efficiency engines, he explained. Raydiance learned the fabrication requirements from these engineers and developed the femtosecond laser-based drilling solutions to keep pace with their fuel-injector advances.
The company’s laser applications engineers created a prototype process for precision hole drilling using early-generation lasers, a laser beam scanning module, and some simple injector nozzle mechanical positioning equipment.
“After successfully achieving the necessary GDI spray nozzle quality in the laboratory, our team of optical, mechanical, electrical, and software engineers work with automotive manufacturers and work cell integrators to develop fully automated, and very fast, fuel-injector manufacturing cells based on the R-Drill 200,” Mielke said.
These advanced machines have now been installed around the world into 24/7 manufacturing environments.