OVERVIEW
A Cupper Press was recently installed in a new can making factory in Europe, which was built near to commercial and office buildings in the surrounding area. Following recommendations from a consultancy specialising in vibration and structural dynamics, the Cupper Press was installed on top of an inertia block supported by spring elements and visco-dampers, offering a system natural frequency of 1.25 Hz. However, high movements were reported on the machines Spring Foundation during production and as a result the vibrations were emitting outwards to the neighboring buildings.
The impact of this movement was premature wear on the machine and increased spoilage, reducing the overall productivity of the plant.
The Challenge
Farrat were contacted to provide a replacement solution that would reduce the excessive movement of the Cupper Press and create a quieter environment for the neighbouring buildings.
Cupper Presses are commonly used in can manufacturing to produce cylindrical cups from rolls of aluminium or metal. The primary action of this type of machine is to punch discs from sheets at high speeds. This action generates vertical excitations at frequencies determined by the speed of the machine, also known as ‘shocks’.
These heavy vibrations have damaging effects on the functionality of the machine installation, its systems and components, and the machines overall productivity. Shock induced vibrations can also damage the building by generating waves and noises that propagate out into the environment. It is therefore crucial to ensure that Cupper Presses are installed on suitable vibration control systems to mitigate against these effects.
The primary element of this challenge was to stiffen the overall system, while preventing excessive vibrations being transmitted around.
The Solution
Farrat’s application engineers considered several system criteria during the design phase, such as the mass, dimensions, and operating speed of the machine, as well as system stability and the isolation performance required to meet the clients challenging requirements.
To resolve both of the clients issues, Farrat engineered a replacement vibration isolation system configured with bespoke bearings made of a steel base and 2 layers of Isomat isolators.
Learn more about the material properties of Farrat Isomat here.
Performance Results
A vibration investigation was conducted by Farrat to measure the level of vibration emitted before and after replacement of the spring packs, to assess the efficiency of the Farrat Isomat System. The results of the survey are presented in the adjacent plot, showing the vertical accelerations measured before replacement with the blue curves, and after installation of the Farrat Isomat Bearing with the orange curves.
Vibrations measured at the feet of the machine are shown on top, on the inertia block in the middle, and on the surrounding factory floor at the bottom. The results were observed at all measured operational machine speeds, between 110 and 170 RPM.
A significant vibration reduction can be seen in each part of the system, particularly at the operational speed of the Cupper Press at slightly below 2 Hz. This is the frequency where the machine is most likely to be moving & rocking, impacting the process quality. The pre-existing system of springs with visco-dampers has proven unsuitable because of its extremely low natural frequency, which is excessively close to the disturbing frequencies generated by the Cupper Press – increasing the risk of resonance issues.
Conclusion
The client’s requirements have been met by the Farrat Isolated Foundation solution, which has significantly lowered the movements of the machine while maintaining a quiet environment for nearby buildings.
This demonstrates the efficiency of Farrat Isomat systems for Cupper Press machine applications, where bespoke design solutions are needed to solve complex engineering challenges.
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