SELECTING & APPLYING THE CORRECT APPLICATION
There are many variables as to when coolant may be beneficial. In addition to reducing temperatures, coolant provides the benefit of reducing re-cutting chips by flushing chips away from the tool. If your application requires coolant, we can modify or create a custom tool to accommodate your coolant fed tooling needs.
COOLANT USES AND INFORMATION
Heat is the single most damaging effect to an end mill in the machining process and proper coolant usage is imperative. Coolant can help control several issues that may arise but must be applied with consistency and accuracy. Applying coolant intermittently can cause the end mill to obtain thermal shock and can have detrimental effects on the end mill.
Coolant creates a layer of lubrication between the endmill, the chip, and the workpiece, helping to control the temperature by minimizing friction. Using the wrong coolant or application can damage the tool as well as the workpiece by allowing heat generation to continuously build. Proper coolant application reduces the cutting temperature as well as promotes good chip evacuation, extending tool life and producing quality surface finishes.
In general, a dull end mill creates more heat than a sharp end mill. The proper amount and precision application of the coolant will disperse the heat and ensure maximum tool life. Depending on your application, a steady stream, mist or occasionally flooding may be applied. Furthermore, many coatings can minimize, or altogether eliminate, the need for coolants. Some properties of coatings are not realized until the cutting temperature reaches a certain point.
Applying an abundance of coolant doesn’t necessarily mean that the coolant is being used appropriately. Administering multiple streams to select areas of the end mill, generally positioned at the point where the cutting tool rotates into the workpiece, has been shown to be more effective than simply dousing the end mill or workpiece with coolant. It is always important to make sure that coolant lines are not impeding the operation, even a momentary interruption in the coolant can damage the cutting tool or workpiece. Constant interruptions in the coolant supply can create thermal shock in the tool and result in premature breakage.
When using high-speed steel end mills to mill steel, coolant is required. Water emulsified cutting oil is the cheapest for most materials and is generally sufficient for traditional milling applications. However, certain materials are commonly milled dry and harder to machine materials can benefit from coolants that use sulfurized, lard, or mineral cutting oils. For cutting aluminum, emulsified cutting oil is ideal, applied in appropriately directed jets or as a mist. Cast iron and plastics usually use air or are dry milled.
When used correctly, the coolant can have several benefits:
• improved tool life
• reduced damage from heat
• improved cutting speeds
• reduced cutting force
• improved chip control
• reduced built-up edge
• decreased damage from re-cutting chips
• improved surface finish