Amada combination machine installed on suspended floor

Switzerland

The Project

A well-respected precision Metalforming company in Switzerland had installed a state-of-the-art Amada EML-2515 AJ3000 Fiber Laser/Punch Combination Machine in a new part of their factory where the floor slab was suspended over the basement car park below. The vibration from the machine resulted in structure-borne noise that was disturbing the offices above and the client was under pressure to find a solution that would be acceptable to Amada.

Acoustic consultants had been brought in to take vibration measurements but then Farrat was recommended to the client in order to develop a holistic solution.

Key value we brought to the project

We analysed the existing vibration measurement data and designed the Farrat Isomat pads to achieve a natural frequency that avoided the varying machine operating speeds and the modal frequencies of the floor slab. Finally, we dimensioned the pads and acoustic washers to fit under each foot and worked with the client and Amada to plan the retrofit.

The results summarised below show that the transfer of vibrational energy from the metal punch to the supporting structure and upper floor, has been significantly reduced. The measurements at the base of the machine show that the Isomat Isolators achieved an isolation efficiency of 89% compared to the rigid coupling. In comparison to guideline values for vibration levels likely to cause structural damage, the risk has been reduced by 80%.

The isolators have significantly reduced vibration levels in the other areas of concern. Measurements taken on the first-floor show vibration levels, when compared to guideline values, have dropped from 3% to 1%. They also show that vibrations have been significantly reduced in all planes thus, likely to reduce re-radiated noise from structure borne vibration.

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High speed punch & fiber laser combination machine was installed on suspended floor resulting in complaints from the offices above.

Amada EML-2515 AJ3000 High-speed punch & fiber laser combination machine installed on a floor suspended between the end wall at the back of the photo and columns seen on the left. Whilst it was a substantial floor the energy from the Amada machine was still enough to excite the floor sending vibrational energy around the building.

Farrat Isomat was chosen as the anti-vibration material as it has been used for decades to successfully isolate impact and precision machinery.

Post installation, where the compact Isomat pads are installed under every machine support, with each pad designed to support the precise loading at that location.

The graph shows the velocity response measured adjacent to the foot of the machine over time, before (red) and after (blue) Isomat is installed. It shows a significant decrease in velocity (19 dB, peak-to-peak) and has a reduction in vibration (from the rigid coupling of the isolation system now installed) of 89%.

These subplots show the amplitude frequency response function in each plane measured adjacent to the foot of the machine. The peaks, more than likely, show the modes of vibration of the supporting slab. It can be seen before (red) there is a peak at 70 Hz which has been reduced in every plane. Overall, the amplitude of vibrations have been reduced in every plane.

This graph shows measurements taken on the Ground Floor at the foot of a column: One of many transmission paths for vibration to travel to the upper floors of the structure. It shows that the amplitude of vibrations have been significantly reduced in every plane.

This final graph shows measurements taken in offices on the first floor. The measurements in the lateral planes were negligible and have not been displayed. It can be seen at 15 Hz that the amplitude has not been attenuated. However, greater than 15 Hz vibrations have been significantly attenuated. This was expected as a key constraint of the design was to control dynamic movement of the machine which limited the ability to use lower natural frequency pads.

As a final sign off SUVA (the largest accident insurance company in Switzerland and an important player in the areas of prevention, occupational safety and health protection) accepted the solution in terms of structure-borne vibration and they also mentioned that ALL machines installed in Switzerland should be on some form of vibration isolation feet.