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It’s Prudent to Revisit the Specifications of a Metalworking Process When It Calls for an Awkwardly Complex Coolant Filtration System

October 01, 2013
James J. Joseph
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The advantages of a MWF management program are well known and practiced in varying degrees of sophistication in almost every metalworking plant regardless of its size.  The benefits are mostly common knowledge for the fluid selection, but there is a growing awareness of the importance of factoring the filter needs while determining the fluid selection. Part of the routine is to study what clarity levels are needed for the operation and the specified fluid; then evaluate the filtration options.  If the three basic limits of time, space and money for the filtration system are challenged, usually the filtration system is modified to accept “trade offs” for a tolerable approach to satisfy operation. Normally they will follow the established specs of the machine builder and tooling engineer. This is good policy and works well for most cases.  However, there is more that can be done by the filter team when an outrageously high cost filtration system for the prescribed operations looks eminent.  The management team can look at trade offs of the operation itself to see if there are better selections for the filtration system. This not to say that the filter engineer can override the builder or tool engineer.  What it does say is the filter engineer should make all those involved in the selection process aware of the potential filtration costs of what is specified.  Hopefully once the economics of filtration needs are known, operational trade offs will also be analyzed to find the most viable concept. The filter person, tooling engineer, and machine designer should act as a team from the beginning with no prejudice toward any of the three components of the project.

The following case history shows how the filtration evaluation milestone in a coolant selection process helped change old habits and drastically reduced the initial cost of buying equipment.

An automotive plant team began a coolant selection procedure to find a fluid to serve a soon-to-be-purchased crankshaft machining transfer line.  The operations included deep hole drilling stations about halfway through the machining line.  The specification called for viscous oil for the drilling stations and specified water-based coolants for the operations before and after the drilling operation.  The machine builder felt that oil was better because drill life would decrease by 50% if a water-based fluid was used.  Since the oil operation was in the middle of the line, the preliminary plans called for a totally separate filtration system for collecting, filtering, chip wringing and storage.  This would have needed two independent cleaning systems on one line: one for water-based fluid, the other for oil.

The filtration evaluation phase uncovered understandable chal¬lenges.  The high cost of filtration equipment for only the oil’s operations was projected to be $750,000.  This also revealed concerns for extra space, cross contamination, extra fluid handling, chip wringing, misting, fluid carry over, spent media disposal and maintenance.

So, the question was asked “do we really need oil?”   It was found that the operations with oil involved just four drills.  A $750,000 price tag is a lot of money for four drills.  Plus, there were all the other issues. The next question was, why not augment the water-based system if the difference was only four drills?  Tests with waterbase coolant showed that the drop in tool life was acceptable.  The filtration system and fluid selection which would serve the waterbase stations were enhanced (at a relatively low cost) to provide better performance for the drilling as well.  The result is one fluid, one system, a cleaner house and lower overall costs.

This episode was filtration-driven in a fluid management atmosphere.  Granted, this is a large facility, but the same disciplines can apply to any size operation for any plant; even for individual machine tools.

James J. Joseph is the principal/owner of Joseph Marketing, located in Williamsburg, VA. You can reach him at josephmarketing@verizon.net. He is the author of Coolant Filtration, 2nd Edition. Click here to read the book review.

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