Toolpaths

Toolpaths are the geometric and procedural instructions that define how a cutting tool moves to machine a workpiece. In CNC manufacturing, a toolpath specifies the tool’s position in three-dimensional space over time, along with machining parameters such as spindle speed, feed rate, and depth of cut. The primary goal of a toolpath is to remove material to achieve the desired geometry while controlling surface finish, tolerances, and cycle time.

Toolpaths can be categorized by operation type and dimensionality. Common 2D toolpaths include contouring, pocketing, pocket clearance, and engraving, used on flat or indexed features. 3D toolpaths handle complex surfaces and shapes, employing strategies for efficient material removal and high-quality finishes. Drilling, boring, and tapping toolpaths generate circular or conical penetrations. In turning, toolpaths define movement along a rotating workpiece. Roughing toolpaths remove material quickly with larger stepovers, while finishing toolpaths emphasize precision and surface quality with smaller steps.

Generation and use: CAM software creates toolpaths from CAD models, selecting tools, strategies, stock boundaries, and clearance envelopes. A post-processor converts the generic toolpath into machine-specific code, typically G-code, with the correct coordinates and control words for a given CNC machine. Verification and simulation help detect collisions and verify stock removal before actual cutting.

Optimization and considerations: toolpath design affects surface finish, accuracy, and cycle time. Key factors include tool selection, stepdown and stepover, feeds and speeds, retract moves, and clearance. Accurate tool length compensation, wear management, and adherence to machine limits are also important for reliable production.