High-pressure coolant tooling

There are high expectations for today’s coolant delivery tooling systems to do more than just cool metal cutting processes. When you choose or are even forced to use coolant, functional efficiency should be at as high a level as possible and be able to present significant opportunities to release hidden productivity. Equally importantly, especially in turning operations, the modern coolant fluid delivery tooling systems must provide effective chip control.

The benefits of using coolant to remove heat and lubricate (reduce friction) are well known; with coolant usually being applied by simply flooding the machining area. Although, for coolant to be really effective, it needs to remove heat quickly from the cutting zone, and a directed high-pressure coolant flow that puts coolant precisely where it is required is much more efficient.

Challenges in cooling the metal cutting process
There are several examples of challenges found at the cross-roads of coolant application and productivity demands in machining, but one of the more striking can be taken from the aerospace materials e.g. titanium alloy Ti6Al-4V. Ti6Al-4V alloy has low thermal conductivity and low modulus of elasticity, making it a suitable material for the high-strength, heat-resistant and lightweight parts in jet engines. However, it is notoriously costly to machine because required cutting speeds are typically quite low, chips are impossible to control and cutting tool life relatively short. Unbroken, long chips can result in chip jamming, subsequent tool failure and, in the worst case, damage costly parts. They can also scratch surface finishes and cause a valuable component to be scrapped.

Bird-nest-like tangles of chips generated by the metal cutting process cause significant productivity losses in attended production, making it almost Bird -nest -like tangles of chips generated by the metal cutting process cause significant productivity losses in attended production, making it almost impossible for machines to run unattended in lights-out operations. This particularly holds true when machining with toolholders or toolblocks with conventional coolant nozzles that are not located close to the cutting edge.

While significant advancements have been made in high-pressure systems, most manufacturers still rely on flood-type coolant systems that drench coolant over a cutting tool and the component being machined to reduce heat. In addition, more flexible coolant nozzles often move, making them inaccurate when it comes to directing coolant to the cutting zone. Such systems also lack adequate control for sufficient pressure.

As flood coolant just washes over the cutting zone, it can also heat up locally to a point where a steam vapour barrier forms. This vapour then actually insulates the cutting zone and keeps heat from dissipating. To combat this situation, high-pressure cooling systems can remove heat fast enough and with enough pressure to prevent such vapour barriers from developing.

Manufacturers must also keep in mind that there are differences between high-pressure coolant delivery tooling systems. The most common of those differences involve distance from the cutting zone, or how far away a system’s coolant outlet is from the workpiece/cutting tool interface. Some system outlets may not be close enough to effectively and accurately reach the optimum point within the cutting zone for the most benefit. Systems that incorporate coolant outlets situated further away from the cutting zone must use higher pressures to compensate for the increased distance.

If a system’s coolant outlets are too far from the cutting zone, additional pumps may be needed. Comparatively, this result in higher costs to achieve the same level of results provided by a system that has oADIDAS