CNC Lathe Turning Operations Flashcards

In CNC lathe programming, G96 activates:

Answer: Constant surface speed (CSS) mode

G96 enables Constant Surface Speed mode, where the controller automatically adjusts spindle RPM as the tool moves to different diameters.

What is the function of the G70 finishing cycle on a Fanuc-style CNC lathe?

Answer: Performs a finishing pass along a defined profile

G70 is the finishing cycle that traces the part profile defined in the G71 or G72 rough turning sequence to remove the finishing allowance.

A negative rake angle on a turning insert:

Answer: Provides a stronger cutting edge

A negative rake angle creates a stronger, more supported cutting edge, making it suitable for interrupted cuts and hard materials.

What does 'dwell' (G04) accomplish in a CNC lathe program?

Answer: Pauses axis motion for a specified time or revolutions

G04 causes the machine to pause all axis motion for a programmed time (seconds) or spindle revolutions, useful for cleaning up grooves or facing.

When programming an internal boring operation, the X-axis values are:

Answer: Larger as the bore diameter increases

In boring, moving to a larger X value increases the bore diameter because the tool moves away from the spindle centerline.

Which insert grade is best suited for high-speed finishing of aluminum on a CNC lathe?

Answer: PCD (polycrystalline diamond)

PCD inserts are ideal for high-speed aluminum finishing because diamond is extremely hard, has low friction with aluminum, and provides exceptional surface finish.

What is the primary purpose of a chip breaker groove on a turning insert?

Answer: To curl and break chips into manageable lengths

The chip breaker groove curls the chip so it fractures into short segments, preventing long stringy chips that can tangle around the workpiece or tool.