Pocket milling (rectangular) in CNC Programming - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is pocket milling in CNC programming?

Pocket milling is a machining process where a rectangular or other shaped cavity is cut into a workpiece by removing material inside a closed boundary.

beginner

Which G-code command is commonly used to start a rectangular pocket milling operation?

G01 is commonly used for linear interpolation to move the tool along straight lines to mill the rectangular pocket edges.

intermediate

Why is it important to use multiple passes in pocket milling?

Multiple passes reduce tool load and heat, improve surface finish, and prevent tool breakage by removing material gradually.

intermediate

What is the purpose of 'stepover' in rectangular pocket milling?

Stepover is the distance the tool moves sideways between passes to ensure the entire pocket area is milled without leaving uncut material.

advanced

How does climb milling differ from conventional milling in pocket milling?

Climb milling feeds the tool in the same direction as the cutter rotation, resulting in better surface finish and longer tool life compared to conventional milling.

What does pocket milling primarily remove from the workpiece?

A Only surface rust

B Material from the outer edges only

C Material inside a closed boundary

D Material from holes

Pocket milling removes material inside a defined closed boundary to create a cavity.

Which G-code command moves the tool in a straight line during pocket milling?

A G00

B G02

C G03

D G01

G01 is used for linear interpolation, moving the tool in straight lines.

Why are multiple passes used in pocket milling?

A To avoid using coolant

B To gradually remove material and protect the tool

C To speed up the process by cutting all at once

D To increase tool wear

Multiple passes reduce tool load and heat, protecting the tool and improving finish.

What does 'stepover' control in pocket milling?

A Sideways distance between tool passes

B Depth of cut per pass

C Tool rotation speed

D Coolant flow rate

Stepover is the sideways distance the tool moves between passes to cover the pocket area.

Which milling type feeds the tool in the same direction as cutter rotation?

A Climb milling

B Conventional milling

C Drilling

D Facing

Climb milling feeds the tool in the same direction as cutter rotation, improving finish and tool life.

Explain the key steps involved in programming a rectangular pocket milling operation.

Think about how you tell the machine where and how to cut the pocket.

Describe why multiple passes and stepover are important in pocket milling.

Consider tool safety and quality of the cut.