Multitasking technology reduces set-up times in production
By using milling-turning units from WFL, BWXT has been able to considerably reduce set-up times and boost the efficiency of its production processes while increasing process reliability with simulation software.
When manufacturing highly complex components, which can take several years to produce, process improvements are extremely important – both in terms of efficiency and quality. For BWX Technologies at their facility in Euclid, Ohio, this was a good reason to invest in multitasking machines in order to exploit potential for optimization. Thanks to the WFL MILLTURN machines, not only have they reduced set-up times, they have also improved their programming and inspection processes.
Precision for the most exacting requirements
BWXT supplies customers in industries such as nuclear, defence and aerospace. Production at the Euclid facility focuses on electromechanical components for the US Navy's carriers and submarines – highly complex parts which subsequently undergo further processing at other sites to create large assemblies. Failures are not tolerated in this environment. The components must function reliably for decades, adhere to tolerance limits of up to ± 0.00025 mm and be manufactured from materials such as Inconel, hardened steel or special stainless steels.
The component sizes vary from smaller formats to workpieces measuring three meters in length and 60 cm in diameter. Up to 15 welding operations are often necessary, and an assembly can consist of over 70 individual parts. Due to small batch sizes (between 10 and 50 pieces), fully automated production is not economically viable. Instead, BWXT relies on a wide range of CNC-controlled machining centres—particularly MILLTURNs from WFL. These enable largely automated, process-reliable machining within the machine (close-door machining) and thus make an important contribution to efficiency and quality in production.
Strategic investment in WFL machines
In 2014, BWXT commissioned its first MILLTURN – an M65 with a 4.5-meter bed length. The aim was to reduce the number of changeovers required for complex machining sequences, as each of these steps is not only time-consuming but also a potential source of errors. In some cases, up to three shifts were required for setup.
The combination of turning and milling in a single machine promised not only greater process reliability but also significantly shorter throughput times. With the use of MILLTURN machines from WFL, setup times were reduced considerably and manufacturing processes were made significantly more efficient. In addition, the simulation software contributed significantly to increasing process reliability.
In fact, for certain components, the number of work steps was reduced from over ten to just three to five—with a productivity increase of 200 to 300 percent. The integrated turning and milling functions achieve performance values that can compete with conventional single machines and also open up new possibilities in the selection of tools and clamping devices.
Machinery fleet systematically expanded
Based on the positive experience, additional machines were purchased. BWXT now uses six M65 machines and one M35, each with different bed lengths and equipment. It is noteworthy that one of the M65 MILLTURNs has nine mounts for prismatic tools, while most only have two. However, all machines have 90 slots in the tool magazine, which represents a significant increase in capacity compared to the machines used previously and allows for redundant tooling.
The simple conversion of the machines also allows flexible machining of small quantities without any loss of productivity or throughput. This enables, for example, the production of internal and external gear teeth on the M35 thanks to various milling cycles – a machining step that could previously only be carried out manually. BWXT is underlining its decision in favor of a MILLTURN with a further expansion. This time, it will be an M50 MILLTURN.
Process reliability through simulation
However, all these enhancements are irrelevant if the individual components are faulty. For this reason, BWXT attaches particular importance to the CrashGuard software that the company has purchased for the WFL machines.