Seth Madore
Seth Madore, an experienced machinist and expert Fusion user explains why Fusion’s deburr toolpath creates retracts and gaps, how to fix it with one simple setting, and alternative strategies for smooth, efficient deburring.
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Deburring should be a finishing touch, not a frustrating bottleneck. Yet, anyone who has tried to deburr complex tooth forms or splines in Fusion knows the struggle: instead of a clean, continuous pass, you end up with broken segments and retracts that slow the cycle and leave inconsistent edges.
This post explains why that happens, how one small setting can fix it, and what alternative toolpaths to use if you don’t have access to Fusion’s dedicated deburr cycle.
Why deburr can be tricky
Fusion’s deburr toolpath often breaks into short moves because of collision avoidance settings—not because the geometry is wrong. By default, Fusion checks the tool shaft and holder for clearance, and if the shaft clearance is set too conservatively, the toolpath retracts to avoid imaginary collisions.
The real issue: Shaft clearance
- Fusion defaults shaft clearance to 1 mm (0.040″), forcing the toolpath to pull back in tight areas.
- This conservative setting can cause gaps and retracts even when the geometry is continuous.
In short: Fusion’s deburr toolpath isn’t broken—it’s doing exactly what you told it to do.
The fix: Set shaft clearance to zero
To get a smooth, continuous deburr pass:
- Edit the deburr tool and open the Tool Data tab.
- Scroll to Shaft and Holder settings.
- Change Shaft Clearance from 1 mm to 0.
- Regenerate the toolpath.
With clearance at zero, Fusion recalculates a clean, uninterrupted path. Always verify in simulation to ensure your real tool and holder won’t collide.
Requirement: Fusion for Manufacturing or the Fusion Manufacturing Extension
The deburr toolpath is part of Fusion for Manufacturing or the Manufacturing Extension, which unlocks advanced strategies and automation features. However, if you don’t have these, you still have options.
Use blend and flow
Before the dedicated deburr cycle existed, programmers relied on surface-based strategies like Blend and Flow. These still work well for complex edges:
Blend:
- Add a modeled chamfer along the edge.
- Use Offset passes set to Surface boundary.
- Increase stepover to minimize passes.
Flow:
- Follows natural surface parameter lines for smooth motion.
- Ideal for curved tooth forms and intricate geometry.
Both methods give you controlled, predictable deburring without the extension.
When scallop still makes sense
Scallop can work for simple edges or when you’re already using it for finishing. But for intricate forms, Blend or Flow generally produce cleaner results.
Key takeaways
- Retracts in deburr paths often stem from shaft clearance settings.
- Reducing clearance to zero can transform a jittery path into a smooth finishing move.
- If you don’t have the Manufacturing Extension, Blend and Flow remain excellent alternatives.
Ready to improve your finishing strategies? Explore Fusion for Manufacturing for advanced toolpaths, automation, and efficiency gains.