BREAKING IT DOWN CHIP BY CHIP

FIVE THINGS TO KNOW ABOUT CHIP FORMATION IN MACHINING

WHETHER EXAMINING HOW TOOL SELECTION impacts chips, how coolant plays a role in chip evacuation or the size and shape of chips, chip formation says a lot about the application being run. Knowing what different chip details indicate allows machinists to manage chip formation better, make adjustments and prevent tool failure. Because when it comes down to it, better chip formation means a more successful application.

SHAPE & SIZE

When looking at chip formation, a key indicator of a good chip is the shape. The preferred outcome for any application is chips shaped as sixes and nines or a single conical shape. These small, manageable chips are essential for efficient, predictable drilling. Nevertheless, it is important to be aware of what chips in other shapes and sizes can indicate. For example, a straight, flat chip is a result of elasticity. If the chip is a continuous ribbon, then there are likely many adjustments that need to be made in order to achieve ideal chips.

The size of the chips impacts evacuation as well. Two major factors impact the size of chips in drilling tools: chip breakers, also known as chip splitters, and lip geometry. With chip breakers, the width of the chip is thinned to allow for easier evacuation; the wider the chip, the easier it is to get it to roll onto itself and break. Lip geometry acts as a mechanical chip breaker to fracture a chip by curling the chip on top of itself or by impacting the chip forming with the backside of the lip radius. Although harder materials will curl a chip on top of itself to create chip fracture, gummier materials often skip over the lip radius and only fracture after impacting the back of the lip radius. Still, the purpose of the combined chip breakers and positive lip geometry is to break off the chip so that it is narrow enough to evacuate easily.