Carbide vs Diamond Endmills for CFRP Trimming

The aerospace industry’s demand for high-precision CFRP trimming has intensified research on tool material selection. While carbide endmills dominate general machining,their rapid wear in abrasive CFRP raises production costs. Diamond tools, though expensive, promise extended durability due to extreme hardness (Vickers hardness: 10,000 vs. 1,600 kgf/mm²). This study addresses two gaps: (1)quantitative comparison of wear mechanisms under realistic cutting conditions, and (2) economic feasibility assessment for high-volume applications.

Methodology

1.Experimental Design

Workpiece: T800S/3900-2 CFRP (fiber volume: 60%, thickness: 12 mm). Tools:

• Carbide: 6-flute, 10° helix, AlTiN-coated

• Diamond: 4-flute, PCD-tipped, 8° helix

Machining parameters replicated Airbus A350 component trimming.

2.Data Acquisition

Tool wear measured hourly via laser confocal microscopy (Keyence VK-X1000). Delamination assessed per ASTM D7268 using micro-CT scanning.

Results and Analysis

1.Wear Progression

Diamond tools maintained flank wear <0.15 mm after 120 min, whereas carbide exceeded 0.5 mm at 75 min, triggering fiber pull-out (p<0.01, ANOVA).

2.Surface Quality

Ra divergence emerged after 90 min: diamond (1.2±0.3 μm) vs. carbide (2.8±0.7 μm).

Discussion

The diamond’s performance aligns with its higher thermal conductivity (500 W/mK vs. 110 W/mK), reducing heat-induced matrix degradation. However, brittle fracture observed at feed rates >0.12 mm/tooth suggests operational limits.

Conclusion

Diamond endmills outperform carbide in wear resistance (>3× lifespan) and surface finish for CFRP trimming.

• Feed rate optimization is critical to prevent diamond tool fracture.

• Future work should evaluate hybrid tool designs for cost-sensitive applications.