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Flow-Through Tools for Metalworking Require Extra Funding for Their High Pressure Coolant System

November 01, 2013
James J. Joseph
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Anyone who calls for flow-through tools should be aware of the extra costs needed for the dedicated coolant system which would prepare and deliver the fluid at the proper clarity, pressure and flow rate required by these tools.  In the last newsletter the selection of an “ideal” fluid for an operation was revisited for the sake of a more realistic filtration system.  This article is offering similar thoughts for selecting flow-through tools, however, now it is not the fluid but the tools themselves.  The spreadsheet for analyzing the justification for this type of tooling should have inputs on the cost of the coolant supply equipment for a comprehensive study.

The coolant supporting hardware for flow-through tools could have significant costs ranging from $20,000 to $80,000, depending on the features, for relatively low flow rates.  The high pressure modules (often called skids) are usually stand alone units, or they can be side arm coolant loops built into the main filter systems.  They have their own reservoir, dedicated filters, precision supply pump and flow control components.   The higher the pressure required, the greater the need for a more sophisticated unit.  The supply pumps which deliver pressures from 600 psi to 3000 psi demand a cleaner coolant than what is needed by the actual machining operations.   Figure 1 shows a typical schematic of a high pressure skid. This has all the fundamental components for controls which would vary with skid design.

Therefore with these precision devices and high equipment costs, you have to ask: are flow-through tools really needed for the operations that are specified?

This is not to diminish the importance of flow-through tools.  They perform a necessary task which cannot be accomplished by conventional tooling.  However, they may be specified for operations where they are not really needed. 

Consider two different selection criteria: 

(1) Primary Operation to Produce the Finished Workpiece

If the flow-through tools are needed to produce quality parts with operations such as deep hole and gun drilling, reaming, or other “deep” feed functions, then the cost of the high pressure system is easily justified. 

(2) Ancillary Operation for Machine Tool Support

If the request for flow-through tooling is made just because it may extend tool life by a few percentage points or is “nice” to have the vigorous chip flushing feature, the justification must factor in the high pressure skid costs.  The extra costs may not be worth it, if conventional tools and flush nozzles can satisfy the need. The cost advantage of flow-through tools for this type of selection could be lost in the extra cost of the high pressure delivery system.

The experience shows that the scope of filtration selection extends beyond just cleaning a fluid.  Moreover, it reveals that the proactive questions of “why” and “why not” at the early stages in the selection process can initiate cost avoidance early in equipment procurement, as well as later in the routine maintenance needs.

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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