Portable Coordinate Measuring Machines Bring Greater Efficiency Ensuring First-Time Quality
Puget Sound Naval Shipyard & Intermediate Maintenance Facility has used portable coordinate measuring machines for about a decade to help mechanics build replacement piping assemblies quicker and more accurately than using tape measures and angle finders.
However, the descriptor ‘portable’ in portable coordinate measuring machines, or PCMMs, is a relative term. The use of CMMs has often been limited due to the large size and heavy weight of the machines. They often have a massive granite surface to hold the components or piping assemblies being measured. These components have to be removed from a vessel or building and brought to the machine, where they are measured to create a 3D file, referred to as a virtual file.
According to Steve Kudrna, 3D metrology and alignment branch manager, Code 290MM, Combat Systems Division Branch PCMMs gather and analyze geometric data to figure out not only the dimensions of something, but also define its physical location and placement in relation to other objects or surfaces in the area.
“A PCMM can replace traditional, iterative methods with virtual methods to reduce time and cost,” Kudrna said. “It can also be used to troubleshoot equipment operational issues or gather new information to find the root cause of any issue that could never be done before with traditional methods.”
Jarod Port, general foreman, Shop 56, Pipefitters, said ‘virtual’ pipefitting has been used to support piping replacements on aircraft carriers, submarines and facilities at PSNS & IMF and other locations. The ability to measure and begin fabrication on a majority of the piping assembly prior to removal has led to an estimated 37 percent reduction in project impact.
Traditional or current PCMMs are articulated arms that have a sensor on the tip, which can be set up near an object or network of objects like pipes. They measure precisely where that sensor is. With the integrated software, a mechanic can touch or trace an object along its outer edges and build an extremely accurate 3D computer file of the object, or even a map of a piping setup.
Newer scanning technologies are generating interest throughout PSNS & IMF. The lofters in Shop 11, Shipfitters, are very interested in the next generation of scanners that use lasers to create exceptionally accurate 3D files of objects. This next generation of scanners do not need to be mounted to decking or on a base. They can be set up on a lightweight tripod, or even handheld in some cases. The newer type of scanners can weigh a tenth as much as traditional PCMM equipment.
According to John Fahey, loft layout supervisor, Shop 11, their accuracy also makes them of great interest to his shop.
“Accuracy, traceability and reliability,” he said. “We can use a laser tracker to measure an object to the nearest one thousandth of an inch, consistently, with traceability. I can show an engineer Objective Quality Evidence that our data was taken accurately and have confidence in that data because the software captures every measurement point in real time. Incorporated within our scans are artifacts that we can measure to accurately define the uncertainty of our data.”
Members of Shop 56; Shop 31, Inside Machinists; and Shop 38, Marine Machinists, all expressed an interest in some of the enhanced inspection, scanning and measuring tools featured at the 2022 PSNS & IMF Technology Showcase. Several of the manufacturers were later invited to demonstrate their tools’ capabilities to shipyard workers looking for faster, easier and less expensive ways to measure things more precisely.
The Metrology Community Growing Within and Among Public Shipyards
“The metrology industry is constantly evolving and new software and hardware is continuously being introduced,” Fahey said. “The metrology community is growing within and among the public shipyards, and having regular interactions and communications with the Metrology Community of Practice has been instrumental in the success of our department.”
Shop 31 mechanics and leadership are interested in streamlining manufactured parts inspections by being able to take these lightweight and precise scanners to the worksite, rather than having to bring the components or assemblies to where current scanners are located.
“This scanning equipment would help prevent the need to remove tooling from the machines for in-process checks and can be portable throughout the shop,” said Harley Nelson, toolmaker planning, design & inspection supervisor, Shop 31.
According to Trevor V. Buechner, virtual pipefitter mechanic, Shop 56, mechanics in his shop are now able to save time by scanning pipe assemblies and beginning the fabrication of replacements before the shipboard assemblies are even removed. Before truly portable PCMMs were introduced into the command, all assemblies had to be removed and taken to a PCMM to be scanned and measured. Only then could replacement assemblies be fabricated based on 3D files.
Given the portability of the newer laser-powered PCMMs, a team from PSNS & IMF could potentially take a PCMM to another location, such as San Diego or Hawaii, and get a head start scanning things aboard a vessel before it even departs to PSNS & IMF for an availability.
“PCMMs are an excellent tool to cut costs and time,” Buechner said. “This technology has its limitations like anything else, but it is a great tool and knowledge for the shipyard to have in its arsenal to help get the boats out on time.”
For more information: www.navsea.navy.mil