SGS Carbide Tool (UK) Ltd is now offering its patented JetStream coolant-feeding technology on a number of its tool ranges. This technology ensures that coolant is efficiently supplied to the shear zone — the interface between the cutting edge of the tool and the raw material of the workpiece that is being cut.
The coolant helps to maintain thermal stability, provides lubrication for the cutting action and also flushes the swarf away to reduce the chance of re-machining chips.
Coolant supplied through the tool can deliver fluid to this high-stress high-temperature area, but as Jeff Burton, executive vice-president of manufacturing, explains: “Coolant holes have a slight weakening effect on the ‘business end’ of the tool, and in cases where the hole or holes only exit the end, the tool needs to be over the workpiece for the coolant feed to be effective. JetStream does not weaken the tool, and it provides cooling when the tip is not over the workpiece.”
During the research and development of the JetStream technology, SGS engineers experimented with different slot locations on the circumference of the tool; helical versus straight feed slots were tested, while different tool types that might benefit from JetStream were subjected to various material cutting trials.
Water-miscible coolant at the coolant suppliers’ recommended strength (usually 5-8%) is fed via the X channel ground into the back of the tool shank. This feeds the coolant to the side grooves that transfer the fluid to the shear zone (the exact grinding profile of the slots used is a closely guarded secret).
Although they are open channels, the slots retain the cutting fluid even at high spindle speeds.
Mr Burton says: “We have tested JetStream in aluminium at up to 10,000rev/min. At that speed — and with a pressure of 1,000psi while using a standard-length tool — the effects of centrifugal force were minimal, and JetStream was still effectively delivering the coolant precisely to the targeted area.”