An automotive engine component manufacturer was experiencing numerous premature failures of drills (gun drills) which were breaking regularly during use. This led to costly downtime, high cost of drill replacements and unacceptable scrap levels. Deep -hole drilling of oil-ways is a high precision process producing high tolerance repeatable holes with an excellent surface finish and is a crucial process used during the manufacture of engine parts.
The gun drill uses a coolant which is injected at high pressure through a hole which runs the length of the drill. This coolant acts as a lubricant and also flushes away the thin curled chips which are formed during the cutting process. John Morfield engineers were asked to investigated the cause of these failures and took coolant samples from the high pressure pump feeding the drills with coolant. These samples were analysed and a high level of fine metallic particulate below 15 microns in size was found.
John Morfield recommended fitting a trial 6um filter system to improve the cleanliness of the fluid to the drill and to test the theory that the high level of fines was contributing to the failures in some way. The trial was conducted over period of three months and subsequent coolant analysis demonstrated a significant reduction in the count of 15 micron particles ensuring that clean coolant was being provided to the gun drills. The customer also confirmed that the premature drill failures had been eliminated.
A high pressure filtration system was then added to the gun drill as a permanent feature. The customer acknowledged a payback time of 6 months covering the supply and installation costs and with annual costs for replacement filter elements being less than £200 this system proved to be a cost effective solution to a very serious problem.
Considering the original costs of premature failures, downtime and scrap levels this system achieved savings of many thousands of pounds each year.