CNC Cutting Parameters and Speeds/Feeds 3

Question 1

What is the effect of increasing depth of cut on cutting forces?

Accepted Answer

Cutting forces increase proportionally with depth of cut

Answer

Cutting forces decrease because the tool penetrates more smoothly

Answer

Cutting forces remain constant regardless of depth of cut

Answer

Cutting forces decrease then increase as depth of cut rises

Question 2

For a CNC milling finishing pass, which parameter combination is most appropriate?

Accepted Answer

Low feed rate, light depth of cut, high spindle speed

Answer

High feed rate, large depth of cut, low spindle speed

Answer

High feed rate, light depth of cut, low spindle speed

Answer

Low feed rate, large depth of cut, high spindle speed

Question 3

What is the formula for Material Removal Rate (MRR) in CNC milling?

Accepted Answer

MRR = Radial depth of cut × Axial depth of cut × Feed rate

Answer

MRR = Feed rate × Tool diameter

Answer

MRR = Cutting speed × Feed rate

Answer

MRR = RPM × Number of flutes × Chip load

Question 4

When roughing hardened steel (>45 HRC) on a CNC machining center, the recommended approach is:

Accepted Answer

Lower cutting speeds, smaller depths of cut, and robust carbide tooling

Answer

High feed rate with maximum depth of cut to minimize total exposure time

Answer

High cutting speeds to prevent built-up edge from forming on the tool

Answer

Climb milling with maximum radial width of cut

Question 5

The optimal chip load for a given end mill is best described as:

Accepted Answer

The manufacturer-recommended range that balances tool life, MRR, and surface quality

Answer

The maximum chip load the tool can handle before breaking

Answer

A chip load so small that no visible chips are produced

Answer

The chip load that produces the shortest chips for easy evacuation

Question 6

In high-speed machining (HSM), which parameter change most defines the strategy compared to conventional machining?

Accepted Answer

Cutting speed (SFM) is significantly increased, often paired with lighter radial engagement

Answer

Depth of cut is significantly increased while feed stays constant

Answer

Feed rate is reduced to compensate for higher spindle RPM

Answer

Number of passes is increased to maintain chip load per tooth

Question 7

When programming a CNC lathe for a facing operation using G96 (CSS), which code is used to set the maximum allowable spindle speed?

Accepted Answer

G50

Answer

G96

Answer

G97

Answer

G94