Often customer applications require more than a standard, “off-the-shelf” product to solve their vibration or shock problem. Fabreeka engineers work with consultants, design firms and OEM customers on a daily basis providing solutions to meet their needs.
An example of this is the approach taken at a large catalog printing company where they were experiencing unwanted vibration in the trimming and cutting area of their facility. The machinery producing the vibration was installed on an upper mezzanine, and during the cutting/trimming process, the structure of the mezzanine vibrated and moved so much that the operators were fatigued and bulbs in the lighting attached to the structure would loosen.
The initial thought by the customer was to install vibration isolators beneath the equipment to stop the mezzanine from vibrating. However, isolators alone had little effect in reducing the vibration in the mezzanine structure. The customer consulted with Fabreeka to provide a solution to the problem. Upon review of the vibration measurements collected on the structure during trimming and cutting operations, it was clear that the structural frequency response of the mezzanine was at or near one of the cutting/trimming frequencies of the equipment – the structural mode of vibration was in resonance with the input frequency of the machinery.
Vibration isolators were not effective in this case due to the frequency of the trimming operation (6 Hz) and the structural mode of vibration (8 Hz). The use of low frequency pneumatic isolators (2-3 Hz) to reduce the input from the trimming equipment and thereby reduce the response of the structure was impractical due to the allowable space for isolators and alignment requirements with other equipment in the trimming/cutting process. The solution involved modifying the structure to make it stiffer thereby changing its frequency response to a higher frequency, thus avoiding resonance with the equipment. Additional cross beams and stiffening techniques were used to increase the mezzanine’s stiffness based on a finite element analysis (FEA) and model of the structure and equipment inputs.