cdsl-cad/backend/agent/skills/cad-engine/references/part-skills/source/atomic/fillet-chamfer-last.atomic.md

Fillet Chamfer Last Atomic Skill

When to use

• A machined part needs edge breaks, deburring chamfers, assembly lead-ins, stress-relief fillets, or small finishing rounds.
• The edge treatment is secondary to the main body, holes, pockets, slots, and bores.

Do not use when

• The rounded or chamfered profile is the primary defining shape, such as an O-ring groove, cam surface, ergonomic shell, or turbine blade.
• A sharp edge is explicitly required for sealing, locating, scraping, or mating.
• The chamfer/fillet would remove critical wall thickness around a hole, shoulder, or thin rib.

Recognition features

• SolidWorks feature evidence such as Chamfer, Fillet, radius values, or angle-distance chamfers.
• STEP evidence with conical or toroidal surfaces near final edges.
• Descriptions mentioning chamfered edges, rounded corners, smooth transitions, edge relief, assembly ease, or stress reduction.

Core invariants

• Apply edge treatments after primary solids, holes, bores, pockets, slots, and patterns are stable.
• Keep edge treatment small relative to nearby feature size and wall thickness.
• Use chamfer for lead-in/deburring and fillet for stress relief or smooth load transition.
• Select specific edges; do not blindly fillet or chamfer every edge.
• Preserve functional shoulders, datum faces, seal lands, and fastener seats.

Parameter roles

• chamfer_distance defines bevel size.
• chamfer_angle defines bevel angle, often 45 degrees when not otherwise specified.
• fillet_radius defines round size.
• edge_set defines which edges receive treatment.
• minimum_wall_after_edge_treatment protects small holes, ribs, and pockets.

Construction sequence

1. Complete the main body and all functional cuts.
2. Identify functional edges that need lead-in, deburring, stress relief, or handling safety.
3. Apply chamfers to hole entrances, exposed outer edges, or insertion edges.
4. Apply fillets to internal corners, web transitions, and load-bearing transitions.
5. Verify that holes, slots, shoulders, and bearing seats remain intact.

Common failures

• Adding large fillets early and causing later cuts or patterns to fail.
• Chamfering a bearing shoulder, seal land, or datum face that should remain crisp.
• Using one global fillet radius across tiny holes and large outer edges.
• Treating decorative edge rounding as more important than functional geometry.

Evidence summary

• Current library evidence: 58 reviewed SCAD58 machined parts with final chamfer/fillet operations.
• Latest run evidence: high-frequency accepted insights for chamfer_edges, chamfer_edges_for_safety, apply_chamfer_to_edges, apply_fillet_to_edges, and stress-relief fillets.
• Frequent operations in the latest run: Chamfer and Fillet after Extrusion, Cut, HoleWzd, Pattern, and Revolution.
• Source: CAD-SkillX offline review of SCAD58 descriptions, STEP summaries, and SolidWorks feature evidence.

Retrieval metadata

Triggers:

• fillet chamfer last
• edge treatment
• chamfered edges
• filleted edges

Secondary triggers:

• deburr
• assembly lead in
• stress relief
• smooth transition
• edge break

Operation triggers:

• chamfer
• fillet
• apply edge treatment after cuts

Exclusions:

• primary rounded profile
• sharp datum edge
• seal land
• cam surface