OD / ID Interpolation Macro Generator

Mode

ID mode uses N29/N35/N36. OD mode uses N80/N120/N130.

Plane Selection

G17: XY arc using I/J. Depth axis is Z.

Program Number (O####)

Default O0001. Example: 30 → O0030

Spindle Mode

End Program Code

X coordinate (#16)

Y coordinate (#17)

First depth (#1)

Final depth (#2)

Depth of cut (#3)

Diameter to make (#30)

Cutter radius (#5)

Enter cutter radius.

Safety engage (#8) (OD only)

Feed (F)

Output starts with % and ends with %. Program header is O####. Plane selection changes the arc axes and I/J/K center words. Validate on your control/simulator before cutting.

Circular Interpolation: G02 & G03 Explained

Circular interpolation commands direct a CNC machine to move cutting tools along circular paths or arcs in standard Cartesian space. The movements are designated by G02 for Clockwise (CW) motion and G03 for Counter-Clockwise (CCW) motion. These commands require target endpoints (X, Y) and arc center definitions (specified either using radius R programming or incremental vectors I and J).

The circular feed rate must also be adjusted when milling circular profiles to ensure the tool's outer edge maintains constant feed. The standard mathematical feed correction formulas are:

Internal Circular Milling: F_adjusted = F_linear * ((D_hole - D_cutter) / D_hole)
External Circular Milling: F_adjusted = F_linear * ((D_boss + D_cutter) / D_boss)

Step-by-Step Arc Programming

Select Direction: Choose G02 (Clockwise) or G03 (Counter-Clockwise).
Specify Coordinates: Input your start points and endpoint coordinates (X, Y) relative to G54.
Specify Vector Parameters: Choose standard R (radius value) or the incremental vectors I and J (X-axis and Y-axis offsets from the start point to the arc's center).
Set Tool & Target Dimensions: Input cutter diameter and linear speed parameters.
Generate G-Code: Instantly view the calculated G-code blocks and the feed rate adjustment report to prevent gouging or slow metal removal rates.

Why IJK Vector Programming is Safer than R-Programming

While R-programming (e.g., G02 X30. Y20. R15. F150.) is simple to type, it presents significant safety hazards. If a typographical error is made in the endpoint coordinates, the CNC control will still force a valid arc radius through the coordinate, resulting in an offset center path and scrapped parts. Incremental vector programming (using I and J offsets) forces a strict geometric check. If the endpoint doesn't match the circle mathematically, the control raises an alarm and stops the machine before a collision occurs.

Circular Interpolation Frequently Asked Questions (FAQ)

Q: What are G17, G18, and G19 G-codes?
A: These codes define the active machining plane. G17 is the X-Y plane (typical for vertical mills), G18 is the Z-X plane (typical for lathes or horizontal mills), and G19 is the Y-Z plane.

Q: Why does my internal bore feel rough or tool-marked?
A: Without feed rate adjustments, the outer cutting edge of the tool moves much faster than the tool center path, resulting in chip overload, surface finish degradation, and chatter.

Q: What is tool radius compensation (G41 / G42)?
A: G41 represents cutter compensation left, and G42 represents cutter compensation right. These allow the programmer to write drawing dimensions directly in G-code, allowing the CNC control to offset the path automatically depending on the tool diameter entered in the machine's offset register.