In the world of CNC machining, achieving a mirror-like finish on curved geometries is often the ultimate challenge. Traditional toolpaths frequently leave behind unsightly "chatter" or tool marks that require hours of manual polishing. However, by optimizing your G-Code, you can eliminate these imperfections at the source.
1. High-Speed Look-Ahead (G05.1/G05 P10000)
One of the primary causes of tool marks on curves is the stuttering of the machine's axes. By implementing High-Speed Look-Ahead commands, the controller processes hundreds of blocks of code in advance. This ensures a constant feed rate and prevents the micro-stalls that create visible lines on a 3D contour.
2. Utilizing Circular Interpolation (G02/G03)
Many CAD/CAM processors default to "linearizing" curves into thousands of tiny G01 straight lines. This creates a faceted surface. Switching to G02 (Clockwise) and G03 (Counter-Clockwise) circular interpolation allows the machine to move in a true arc, resulting in a significantly smoother surface finish.
3. Optimizing Stepover and Scallop Height
To eliminate "scallop" marks, the G-Code must balance the stepover distance with the tool’s radius. Using a 3D constant stepover strategy ensures that the distance between passes remains uniform, regardless of the slope of the curve, effectively neutralizing the peak-and-valley effect on the material.
Pro Tip: Always verify your "Tolerance" settings in your CAM software. A tighter tolerance (e.g., 0.005mm) results in denser G-Code but a much more fluid motion on complex curves.
Conclusion
Eliminating tool marks isn't just about the machine's rigidity; it’s about the intelligence of the instructions provided. By mastering G-Code optimization and understanding axis acceleration, you can produce professional-grade curved surfaces straight off the mill.
CNC Machining, G-Code Tips, Surface Finish, 3D Milling
