Drilling Head PDC

Drag bits also named blade bits, with a TC inserts on the blades. They are usually designed for drilling in soft formations such as sand, clay, or some soft rock. Their uses include drilling water wells, mining, geothermal, environmental and exploration drilling. Whenever possible, they could be used to drill pilot holes, since they produce cuttings that are easiest to log. 
Normally it’s made with three wings for one drag bit, while sometimes those with four wings or five wings will also be required.