Tips To Prevent Overcutting In CNC Machining

Overcutting in CNC machining happens when the tool removes material from areas it shouldn’t, leading to size deviations, quality issues, and potential part scrapping. Here are some common causes and ways to prevent it:

Common Causes of Overcutting:
1. Tool Deflection: Tools that are too long or thin may bend during machining, causing excess material removal.
2. Uneven Stock Allowance: Variations in material thickness (e.g., 0.5mm on one side, 0.15mm on another) can lead to uneven cutting.
3. Incorrect Cutting Parameters: A too-fast feed rate or improper depth of cut can result in unwanted overcutting.
4. Operator Error: Mistakes in setup, tool selection, or programming can also cause overcutting.

How to Prevent Overcutting:
1. Use the Right Tool: Opt for the largest diameter and shortest length tool to reduce deflection and improve machining precision.
2. Maintain Consistent Stock Allowance: Ensure uniform material allowance and use corner-cleaning toolpaths to balance tool load.
3. Fine-Tune Cutting Parameters: Adjust feed rates, depths, and use arc transitions for sharp corners to avoid excessive material removal.
4. Utilize Spindle Speed Override: Real-time speed adjustments help control tool load and reduce overcutting.

Have you faced overcutting in your machining processes? What strategies have worked for you?