Tool life economics and quality comparison for PCD versus coated carbide when machining CFRP and GFRP stacks.
The economic crossover point
PCD tools cost 8–12× more than coated carbide upfront, but in CFRP machining they routinely deliver 60–80× the tool life. The break-even typically lands around 200 holes for drilling and 50 m of linear cut for routing.
Head-to-head wear data (CFRP, 4 mm Ø drill)
Production trial across three shops, identical fixtures, identical feeds.
| TOOL | HOLES TO WEAR LIMIT | DELAMINATION INDEX | COST PER 1000 HOLES |
|---|---|---|---|
| Coated carbide | 180 | 2.4 | US$ 142 |
| PCD brazed tip | 14,500 | 0.6 | US$ 38 |
| PCD veined | 22,000 | 0.5 | US$ 31 |
Edge quality on composite stacks
Delamination and fiber pull-out at the exit face are the dominant quality failures in CFRP. PCD’s chemical inertness and razor-sharp edge geometry produce a substantially cleaner exit hole, often eliminating the need for a backing block.
When carbide still wins
PCD is not always the right call:
- Prototype runs under 100 parts — capital cost dominates.
- Mixed stacks containing titanium — diamond reacts with Ti at temperature.
- Frequent geometry changes — carbide regrinds cheaply.