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:

Release Note

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.

Programing Example

Inserting chamfers and roundings (G301/G302)

Chamfer: 90° corner with 2 straight lines (I=20 is specified for a chamfer 20x45°)

N100  G00  G91  X100  Y0

N110  G01           Y100 F200

N120  G301 I20

N130                X-60

N140  G00  G90  X0  Y0

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.

Release Note

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.

Programing Example

Inserting chamfers and roundings (G301/G302)

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

N05  G17 G00 G90 X0 Y0

N10  G01 F2000 X100       G301=20 #FRC=500

N20                 Y100  G302=20 #FRC=1000

N30            X0         G301=20 #FRC=500

N40                 Y0    G302=20 #FRC=1000

N50  X40

N50  M30

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:

Programing Example

Rectangular pocket with 2 chamfers (#CHR, #CHF) and 2 roundings (# RND) with specific feedrates

N05  G17 G00 G90 X0 Y0

N10  G01 F2000 X200       #CHR=20 #FRC=500

N20                 Y100  #RND=20 #FRC=1000

N30            X0         #CHF=35 #FRC=500

N40                 Y0    #RND=20 #FRC=1000

N50            X40

N60  M30