Inserting chamfers and roundings (G301/G302) (#FRC/#CHR/#CHF/#RND)

G301 inserts a straight line at the identical angle of inclination to the adjacent contour elements (chamfers).

G302 inserts an arc with a tangential transition to the two adjacent contour elements (roundings).

These functions are non-modal and generate precisely one insertion segment (arc or straight line). G301/G302 blocks may be only written between blocks with active G functions of the group "G00, G01, G02/G03 except for G05”.

The I word programmed in the same NC block defines the rounding size or the chamfer width of the insertion segments in [mm, inch]. The I word remains stored and active. This means that I word need no longer be programmed in the following G301/G302 at the same radius or same chamfer width.

In the initial programming of G301/G302, an I word unequal to zero must be programmed in the NC block, otherwise an error message is output (error which leads to abortion of decoding).

Effectiveness of path feedrate in an inserted chamfer or rounding segment:

• If the previous feedrate is G00 (rapid traverse), the segment is also travelled at maximum possible velocity.
• If the previous feedrate is G01/G02/G03, the programmed feedrate is also valid in the segment.
• A feedrate may also be specified in a block containing G301/G302. This feedrate is also valid in all following G01/G02/G03 blocks.
• The feedrate is also adapted when G11 and G41/G42 are active.

Specific chamfer or rounding feedrate:

As of Build V3.1.3057.04, an active feedrate can only be programmed in the inserted chamfer or rounding segment together with a specified chamfer or rounding.

Programming Example

Inserting chamfers and roundings (G301/G302)

Rounding: rectangular pocket with corner radius 20 mm, length 200 mm, width 100 mm, segment-specific feedrates

The chamfer or rounding is always added in the plane in which the second motion block is programmed.

Example A and B both yield the same result, contouring in the Y-Z plane.

As of Build V3.1.3057.04 there are additional options to program chamfers and roundings:

Extended G functions G301 and G302:

Chamfers and roundings are programmed as additional values with G301 and G302. Chamfers and rounding values must always be specified in [mm, inch]; they are non-modal.

G301 and G302 can be programmed directly in the first motion block. A separate NC block is not required.

Programming Example

Inserting chamfers and roundings (G301/G302)

Rectangular pocket with 2 chamfers (G201) and 2 roundings (G302) with specific feedrates

Programming chamfers and roundings with # commands:

Chamfers and roundings are programmed as additional values with# commands. Chamfers and rounding values must always be specified in [mm, inch]; they are non-modal.

# commands can be programmed directly in the first motion block. A separate NC block is not required.

A chamfer can be programmed in two ways: either by specifying

• chamfer width (analogous to G301) or
• chamfer length

Rounding is programmed by:

Programming Example