[image-62]"Most spacecraft are manufactured with welded tube connections," said Ed Havenor, a senior engineer in the Laboratories Department at the NASA White Sands Test Facility.
To safely and precisely weld small, high pressure tubing systems for spacecraft and ground test systems, including the Space Shuttle, technicians need a tool that will face and trim the outer surface of the tubing and also trim the inner surface for a precise, leak-proof fit, to ensure weld integrity, and to ensure that the weld joint doesn't interfere with the flow area in the tubing.
To trim tubing in the past, technicians used a commercially available de-burring tool that attaches to a drill motor. The cutting blades had to be physically adjusted to fit the tubing by technicians reaching inside a small cage to adjust the blades. Often the technicians had to trigger the drill motor to align the tool so they could reach the blades and make the adjustments. After the adjustments were complete, the drill motor was used to trim the tube ends.
After an employee injury occurred with the existing tool, it was recognized that a new, safer, and more precise de-burring tool was needed. Responding to the request to create a new tool, the WSTF's Hardware Processing Machine Shop went to work.
[image-78] Led by Russell Gardner, a team designed and fabricated the new de-burring tool. The team included Randy Hignight, Joe Woytach, Beau Bradbury (the engineer who drew up the concept), Bruce Havenor, and Bill Weed. They used commercial off-the-shelf parts to create a de-burring tool that embodied the precision needed for spacecraft orbital welding, included cutters for every size and thickness of tubing needed, and would do the job safely.
"We designed the new cutter based on how a machinist would run it," said Gardner, a machinist specialist in the Hardware Processing Department's Machine Shop. "First, we wanted to fix the safety problem by taking all the unsafe steps out of it. We wanted a cutter with a different spindle speed for each cut, and one that cut precisely without chatter. All in all, we wanted the user in the field to be able to cut precisely, just like we would in a precision machine shop."
Cheerie R. Patneaude
NASA JSC White Sands Test Facility