Low frequency noise and vibration from a aluminium die casting injection operations had caused extensive complaints from nearby residents. This led to the involvement of the Environment Agency (EA), the local press and the local MP…
The wrong measurements over months...
The noise consultants employed carried out extensive noise and vibration measurements for many months - to no avail. The lack of avail was caused by a poor understanding and diagnosis of the problem that led to them to measure the wrong noise parameter, dB(A).
As the noise complaints were actually caused by "thumps" with a frequency largely below 50Hz they could not possibly contribute to the measured dB(A)...
The rapid diagnosis and low cost solution
We were recommended to the company by the EA as an option for a 2nd opinion. A single day on site resulted in the problem being diagnosed as hydraulic lock in an aluminium injection moulding die cast machine.
Our recommended solution was to fit a small hydraulic accumulator costing c £300 at the correct location, a process that took all of 10 minutes. This not only solved the noise problem as shown in this noise signature, it also reduced the mechanical stresses in the machine, cutting maintenance requirements.
This is a classic (and not uncommon) case of misdiagnosis and a lack of understanding of the causes of noise complaints needlessly prolonging the stress on local residents. It also resulted in unnecessarily high (and ineffective) consultancy fees, not to mention the bad publicity for the company.
