"The training class usually consists of an eight-week course, and it combines classroom and lab experience. The classroom portion especially provides the structure we feel promotes good skill growth," notes Trudelle. The program is not easy, and it does not allow for skills to atrophy. Every operator must take and pass a re-certification test every two years.
"Because of this structure, I get a more efficient personnel draw," says Mark Nolan, lead welder, department 400 (which is responsible for engine-related repairs). "Engine manufacturers like Pratt & Whitney and General Electric specify welding requirements, and of course we have to satisfy the FAA. With operators trained on welding seven metals and tested in both the flat and vertical positions, we have a large talent pool for any job required."
Welders at TOC respect the training program not just for its results, but for the quality of its instructors. Collier and Trudelle have a combined 34 years of welding experience, much of it related to aircraft.
"Because they know aircraft components and the metallurgical properties of aircraft metals, Collier and Trudelle can apply that knowledge in training," says Charles Pierce, a welder in department 400. "They bring out our skills in ways that help us prepare for real-world challenges. That's a big difference between Delta TOC training and training you'll get anyplace else."
Welding knowledge in action
Working on the magnesium (Group 5: AZ31B) JT8 gearbox for a Boeing 727 clearly illustrates the difference between general TIG welding and TIG welding on an aircraft component.
The gearbox functions similarly to a car's transmission, except at $47,000 per half, it costs more than most cars. Like a transmission, it wears down. To salvage this expensive component, TOC welders cut out worn or damaged sections and replace them with new metal using a Syncrowave power source welding in the AC TIG mode. This buildup work, adding layer upon layer of weld metal, puts a lot of heat into the component. Unfortunately, excess heat warps the gearbox to the point where the two halves no longer match; the warped half then has to be scrapped.
"Today, we know the heat limits of this part, so we'll run a short bead then wait a few seconds for the part to cool before making the next pass," says TOC welder Vincent Brigante. "This is why it makes sense for the TOC training program to include a weld test that requires arc stops and starts."
Brigante did have problems, however, with the oil contaminating the magnesium. After spending a week adding new metal, he frequently encountered contaminated sections. Cutting out the contaminated section often meant cutting out all the new weld metal, too. Today, through proprietary welding repair techniques developed by Brigante, Trudelle, and others, Delta has eliminated this problem and extended the life of the gear box from 400 to 600 cycles to more than 12,000 cycles (a cycle is a takeoff and landing).
"Welding that gearbox got real personal," says Brigante. "We vowed never to scrap one, and we haven't scrapped one in more than 12 months."
Mike Sammons is a product manager for Miller Electric Mfg. Co.
Miller Electric Company
Senior Certified Welding Inspector (SCWI)
SCWI status is certainly special to the individual who has obtained the designation. It is AWS’ highest level of certification, says Wendy Sue Reeve, AWS. She explains that through successful examination, SCWI is awarded to an individual who has been a CWI for a minimum of six years, has a requisite 15 years of experience, and whose career has evolved into a supervisory or management position with responsibilities in the field of quality control and quality assurance. The person has an understanding of advanced nondestructive examination (NDE) topics, quality systems, procedure qualifications, and other identified SCWI knowledge areas.
Better Starts, Same Welding Arc
The new Syncrowave 250 DX, now being used by aircraft welding operators at Delta Air Lines, produces dramatically better arc starts through its selectable start condition feature. This three-function control ensures consistent and repeatable high-frequency AC and DC arc starts.
To prevent burn through when welding thin metal, Miller Electric™s Syncrowave 250 DX and 350 LX AC/DC TIG welders now have improved low-end DC TIG arc starting capabilities. While Miller...