Impregnated diamond bits
Rotation speed - Load. Drilling parameters.

ROTATION SPEED - INDEX PENETRATION

• The drilling parameters from the table, shows reference values to the driller.
• As general rule the Impregnated diamond Bits need higher rotation speed comparable with those of surface set bits, due to the less diamond exposure. The weight on the bit is secondary. To calculate the rotation speed, we recommend to work with a periferical speed from 2.5 to 3.5 meters per second.
• The index of penetration (I.P) is calculated, dividing the rotation speed (rpm) by the penetration rate (cm/min.). Provide to the driller an indication that the bit is drilling properly.

	I.P. =	rpm
		cm/min

Penetration index recommended = 80 to 100 (Optimum performance)

Ie: Bit drilling to 1000 rpm with penetration of 10 cm/min

	I.P. =	1000	= 100
		10

Bit drilling to 800 rpm with penetration of 10 cm/min

	I.P. =	800	= 80
		10

With index below to 80, excessive bit wear will occur.
With index over to 100 the bit can be polished.
When the driller can not modified parameters of rotation speed or weight on the bit, he has the option to change to lower or higher number of the bit that is using, achieving the adjustment of the Penetration index between 80 and 100.