Machine tools deliver cutting coolant basically in one of two ways – either through separate individual nozzles that flood the cutting zone with coolant or via systems that send coolant down the sides of a cutting tool or actually through internal channels within the tools themselves. While flood-type coolant is effective for many machining operations, some benefit more with pinpointed and directed streams of coolant provided by coolant-through cutting tools as well as certain types of tool holding systems. The import factor for shops to remember is that regardless of the type of coolant they need there are several options to consider for achieving the most efficient and directed coolant delivery.
While the most common option for turning and milling machines is through coolant capabilities, it’s an option that shops must know they will need and specify at the time of machine purchase. But what if that need isn’t realized until years after the purchase? For these shops, today’s retrofittable through-coolant systems provide a solution to turn flood coolant into through coolant.
As opposed to expensive, high-maintenance through-coolant-dedicated live tooling heads, such systems allow shops to quickly, easily and cost effectively transform the standard external-coolant tooling heads on mills and/or turning machine turret stations into those with through-tool-coolant capability. Shops gain all the benefits of through-the-tool coolant delivery – longer tool life, more efficient chip control, less heat generation for faster speeds and feeds and thus shorter cycle times and increased productivity. Plus, they avoid the high initial cost of dedicated through-coolant heads as well as the required routine maintenance (O-rings and lubrication) along with the complete system rebuilds needed every other year or so.
One recently developed type of retrofittable through-coolant system makes use of coolant-inducing technology. Through a special clamping nut, the system induces a tooling head’s external coolant supply into a collet holder cavity. Also, because it brings the coolant in through the collet cavity, it prevents coolant from seeping back into the internal compartment of the live tooling head to eliminate the maintenance issues of dedicated through-coolant heads.
During operation, machine tool coolant fills a small gap between the system’s rotating component and a mating stationary nut. Once the gap is full, a liquid bearing forms and reduces friction and dissipates heat caused by system rotation.
Another common option for achieving the most efficient and directed coolant delivery, especially for milling heads, are metallic sealed collets and coolant nuts for use with ER tooling systems. Shops can use ER tool holders with regular non-sealed collets to achieve through-tool coolant or peripheral coolant that is directed down and around along the sides of cutters. Sealing collets are most often used for drilling applications to increase tool life, drill to full hole depth and eliminate the need for pecking operations.
Some sealed collets use rubber or silicon. However, those that do run the risk of the rubber or silicon degrading over time. Metal, on the other hand, provides much longer tool life without deterioration.
There’s no question that better directed coolant – whether by through-tool methods or systems that provide peripheral tool cooling – is beneficial for optimized machining performance. A better directed coolant stream contributes to reduced cycle times, extended tool life and effective chip removal. Plus, retrofittable systems provide a cost-effective alternative to expensive, high-maintenance through-coolant-dedicated live tooling heads.
Learn more about easy, cost-effective ways to take a more direct route to efficient cutting tool coolant.