Question 1

How do I choose the right cutting speed for a new material?

Accepted Answer

Start with the tool manufacturer's recommended cutting speed for the workpiece material and tool grade. Reduce by 20-30% for the first test cut and increase gradually. Key factors: harder materials need lower Vc, rigid setups allow higher Vc, interrupted cuts need 20-30% reduction, and coolant type can allow 10-20% increase.

Question 2

What happens if I increase feed rate versus cutting speed?

Accepted Answer

Increasing feed rate is generally more efficient — it raises MRR with less impact on tool life than increasing cutting speed. Doubling Vc roughly halves tool life (Taylor's equation), while doubling feed rate reduces it by only ~30%. However, high feed rates increase cutting forces and can affect surface finish. For roughing, maximize feed; for finishing, optimize speed.