Large Inertia Bases for Vertical Boring Machines, Project Shine, Oxford
Mason U.K. designed and installed two large inertia bases to isolate vertical boring machines in the Ernest Rutherford Laboratory, Oxford. Precision manufacturing facilities are located close by, which could not tolerate the vibration produced by these machines.
We designed the bases and managed their installation. The 40,000kg mass of each base is supported on Mason SLF spring isolators, with a natural frequency of 2.4Hz. This system has been designed to offer a stable platform to operate the machinery while providing near total isolation.
The vertical borers will be used to test industrial diamonds by grinding away 1000kg granite blocks. An acoustic enclosure will surround each machine as well as rails and other safety/access equipment. The design of the bases allow for this extra mass and can be adjusted to suit future requirements.
The best data available to us when designing suggested a spring natural frequency of 2.0Hz was required. Providing frequencies this low can be problematic due to the risk of exciting the slab. This is not a problem for larger floors due to high system inertia and inherent damping but this isolated slab was not so large and very stiff.
We therefore installed rubber dampers under the slab. These only came into play if the slab started to move excessively, at which point they came into contact and raised the system natural frequency. This was a rare occurrence and only happened in very specific conditions. The dampers worked very well and had negligible effect on the system’s isolation performance.
Mason U.K. can offer a full design and consultancy service for bespoke solutions such as this. For this project we offered guidance to derive the correct solution and managed the complete design and installation of the bases.