The Shock Pulse Method
The shock pulse method (SPM) was developed in Sweden in the 1960s. Its exclusive purpose was – and still is – to monitor the operating condition of rolling bearings, to get advanced warning of developing bearing damage and to enable planned bearing replacements with a minimum of downtime and risk for machine failure. Over the years, the method was refined to evaluate the lubrication condition of undamaged bearings so that the user can not only detect existing damage on rollers and raceways, but prevent the most common cause of early bearing failures by optimizing bearing lubrication in any given application.
Since the rise of vibration analysis as a condition monitoring method, companies have tried to achieve bearing damage detection through various forms of spectrum analysis, without reaching the same degree of operational ease and reliability provided by the Shock Pulse Method.
Maintenance – three alternatives
There are three basic maintenance philosophies:
Corrective maintenance: wait for the breakdown, then repair. This method is suitable for easily replaced parts whose failure will cause little inconvenience. Used for important machinery, you run an increased risk of downtime during required time, for administrative and technical delay, and for secondary failures.
Direct preventative maintenance: This is planned maintenance at defined intervals, e.g. lubrication, cleaning, bearing replacements. The method disregards the actual operating condition of the part or machine. It is inefficient for unpredictable components like bearings (waste of potential life, risk for installation faults, no real security).
Predictive (preventative) maintenance: Maintenance is condition based, which means that repairs or replacements are made only when a significant deterioration in machine condition is detected, and largely during “non-production time”.
Detecting early-stage faults in time for planned repairs requires condition monitoring. Correctly used, the method reduces unplanned stops, secondary failures, administrative and technical delay, and spare part stock.