Recycling Right
- 25 Aug, 2025
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In high density PCB fabrication, drill bit failure is a major contributor to rising production costs and quality inconsistencies. As drilling speeds exceed 100,000 RPM and layer counts increase, conventional tools face challenges such as resin adhesion, rapid edge wear, and hole deformation. These lead to frequent tool changes, scrap, and reduced throughput.
Rainbow TAC is NTI Nanofilm’s proprietary taC coating, created using its advanced Filtered Cathodic Vacuum Arc (FCVA) platform. It forms a filtered tetra amorphous carbon (taC) layer that is ultra hard, ultra smooth, and tightly bonded to the drill surface. Deposited at low temperatures below 100 °C, this layer enhances durability and reduces friction while preserving the geometry of micro sized carbide drills used in high speed, multi layer PCB manufacturing.
Raising the Bar Beyond Traditional Coating Methods
Traditional coating methods such as electroplating, anodizing, PVD, and CVD were not designed to meet today’s extreme PCB drilling demands. These techniques often produce brittle or uneven films, have substrate limitations, or require high process temperatures that compromise tool geometry.
NTI Nanofilm’s FCVA technology solves these issues by delivering a dense, low particle filtered taC coating with excellent edge coverage and strong adhesion.
The table below illustrates the differences:
| Coating Method | Electroplating | Anodizing | PVD | CVD | FCVA (Rainbow TAC) |
| Deposition Temp | <100 °C | 40 to 60 °C | 200 to 500 °C | 400 to 800 °C | <100 °C |
| Hardness (Hv) | ≤1,000 | ≤500 | ≤3,000 | ≤2,000 | ~5,000 |
| Friction Coefficient | 0.5 to 1.0 | 0.6 to 1.0 | 0.3 to 0.6 | 0.2 to 0.4 | <0.1 |
| Adhesion | Fair | Fair | Good | Good | Excellent |
| Limitations | Poor wear | Brittle | Density limits | Heat damage | NA |
Filtered taC coatings achieve reliable performance even at just 0.1 to 0.2 micrometers in thickness, maintaining edge sharpness while meeting PCB tooling tolerances.
Unlocking Proven Performance Gains in PCB Drilling
Performance validated through joint evaluations with customers on 16 layer FR4 boards at 120,000 RPM demonstrated that Rainbow TAC significantly improves tool life and hole quality.
The results:
| Metric | Uncoated | TiN / DLC | Rainbow TAC (FCVA) |
| Hardness (GPa) | 15 to 18 | 20 to 30 | 50 |
| Friction Coefficient | 0.7 to 1.0 | 0.1 to 0.6 | <0.1 |
| Tool Life | 1x | ~1.5 to 2× | Up to 3× |
| Drilling Defects | Severe | Moderate | Up to 41 % fewer |
These joint evaluations further confirm Rainbow TAC’s endurance advantage. In flute wear testing, coated drills remained sharp for over 7,500 hits compared to 2,500 for uncoated tools. In routing, they maintained dimensional accuracy across 60 meters of travel, three times longer than standard drills. Such improvements are enabled by NTI’s FCVA technology, which produces a denser, smoother, and more durable taC layer than conventional methods.
Empowering Fabricators with Long Term Efficiency and Quality
With 83 percent of the global PCB drill bit market dominated by a few suppliers, fabricators are under pressure to reduce costs while maintaining quality.
Rainbow TAC helps manufacturers achieve:
- Up to 3× tool life vs. uncoated tools
- Up to 2× performance vs. TiN or DLC coatings
- 41 percent fewer defects including burrs, nail heading, and wall roughness
- Low temperature, low particle coating for cleanroom compatibility
- IPC Class compliance
- Lower cost per hole with longer intervals between tool changes
Filtered taC, applied using NTI’s proprietary FCVA technology, is more than just a harder carbon layer. It is a precision engineered coating designed to meet the demanding requirements of next generation PCB manufacturing. For fabricators focused on yield, consistency, and cost efficiency, Rainbow TAC delivers measurable performance gains and a reliable path to process improvement.