How To Machine a Relief Precisely to a Vector Boundary

Overview

When machining a 3D relief within a boundary vector, tool geometry can cause unexpected overcuts — especially at edges. This tutorial shows how to machine a relief exactly to a vector boundary using offset vectors and separate toolpaths for each tool diameter.

Understanding the Problem

In Carveco, toolpaths use the center of the tool to follow the vector. That means when you're trying to finish a relief right up to a vector boundary, the actual cut may extend beyond your intended edge unless you offset accordingly.

Step 1: Simulate the Original Toolpath

1. Generate and simulate your roughing and finishing toolpaths.
2. Rotate and inspect the top and side views. You’ll notice the cut extends past your boundary.

Step 2: Offset Your Vector for the First Tool

1. Select your boundary vector.
2. Use Offset Vectors to offset inwards by half the tool’s diameter.
3. For a ¼” end mill, offset by 0.125".
4. Create a Machine Relief toolpath using this new vector.

Step 3: Offset Again for the Second Tool

1. Repeat the process for your finishing tool. For a 1/16” ball nose, offset the vector inwards by 0.03125".
2. Create a second Machine Relief toolpath using this smaller vector and tool.

Step 4: Simulate and Verify

1. Simulate both relief toolpaths together.
2. Observe how cleanly the relief finishes at your original boundary vector.

Troubleshooting

• Overcutting persists? Double-check your offset values and ensure you're using the correct tool diameter.
• Tool doesn’t reach the edge? You may have offset too much. Confirm the units and direction (inward vs outward).