Diamond-coated tools have transformed the precision machining of challenging materials by providing unparalleled hardness, durability, and efficiency. As a leader in cutting tools, TaeguTec has made substantial investments in diamond coating technology to create tools that enhance machining performance across various industries, including aerospace, automotive, and defence. PES reports 

TaeguTec introduced its diamond-coated tools eight years ago, initially focusing on solid carbide drills and endmills. Over time, the company expanded its offerings to include indexable inserts for milling and turning applications. TaeguTec keeps the diamond coating process in-house which provides greater process control driving quality and innovation. 

Jin Cheon, TaeguTec’s round Tool product manager says: "We were one of the first companies to bring diamond coating in-house. This move gave us a competitive edge because we can fine-tune the process to match our customers’ needs."

To maximise tool life and performance through reduced tool wear and improved heat resistance, TaeguTec primarily uses two types of diamond coatings. The Korean manufacturer’s micro-crystalline diamond coating is specifically designed for machining highly abrasive materials such as graphite and ceramics.

This micro-crystalline is selected for its exceptional wear resistance. In contrast, TaeguTec also offers a nano-crystalline diamond coating that is ideal for machining composite materials, such as Carbon Fiber Reinforced Plastic (CFRP) and Glass Fiber Reinforced Plastic (GFRP), as it provides smoother surface finishes and reduces the potential for delamination and uncut fibres during machining.

As one of TaeguTec’s R&D specialists, Mr Jung, explains: "Micro-crystalline coatings are ideal for high-wear environments, such as those found in graphite machining. However, a smoother, nano-crystalline coating is preferred when working with composites, as it reduces delamination issues and creates a sharper edge on the tools. It’s all about applying the right technology for the right job."

Due diligence

To ensure complete process control and provide the company with scope for development, TaeguTec invested in the HF-CVD diamond coating technology from one of the most advanced diamond coating equipment companies. After rigorous testing and due diligence in the marketplace, the technology was chosen for its superior optimisation for cutting tools.

“We evaluated multiple technologies before selecting our supplier. Their equipment provided the best balance between performance, consistency, and cost-effectiveness. By controlling coating thickness and structure, we can tailor our diamond coating process and the respective tools to meet diverse machining demands," says Mr Jung.

One major innovation attained via the HF-CVD diamond coating system is the ability to customise the thickness and grain structure of the diamond coating. This enables TaeguTec to optimise wear resistance and cutting edge sharpness. The company fine tunes these parameters to maximise tool life, developing tools from the molecular structural phase. 

“By controlling the coating thickness, we ensure that our tools remain sharp while maintaining their durability. Too thick and the edge dulls; too thin and the tool wears out quickly," Mr Jung emphasises.

Of course, the coating is only as good as the coating process, adhesion and tool composition. TaeguTec recognises this and has made crucial advancements in cobalt leaching to improve coating adhesion. Cobalt serves as a binder in tungsten carbide substrates, making it a crucial element in carbide cutting tools. 

Cobalt can interfere with the diamond adhesion process so TaeguTec removes surface cobalt through an in-house specialist acid treatment process to enhance the bond between the substrate and the diamond coating. 

“Cobalt can act as a barrier between the carbide and the diamond coating. Our process eliminates that issue and ensures stronger adhesion,” Mr Jung adds. “Fundamentally, the TaeguTec process removes the surface cobalt to greater depths than alternative methods. This means the adhesion of our diamond coating is far superior, delivering significantly improved performance and tool life," 

Additionally, application-specific geometry adjustments play a vital role. TaeguTec designs tool geometries tailored to applications specific to the aerospace, automotive, and semiconductor industries, among others. This ensures that the sharpness of cutting edges is maintained while guaranteeing sufficient coating thickness for durability.

TaeguTec’s diamond-coated tools also provide significant cost savings in these high-performance industries. Their extended tool life reduces downtime and the frequency of tool replacement, thereby increasing production efficiency. 

Another significant benefit is the superior heat resistance of diamond coatings. Compared to conventional carbide tools, diamond-coated tools maintain their integrity at significantly higher temperatures, making them ideal for high-speed machining applications. “Heat buildup is a significant issue in precision machining. We can eliminate most of that issue with diamond-coated tools, allowing for more aggressive cutting speeds without compromising tool performance," Jin Cheon notes.

Industry solutions

TaeguTec’s diamond-coated tools have been widely adopted in industries requiring precision machining. In aerospace, CFRP components in aircraft wings and structural parts require smooth cutting to avoid fibre delamination. TaeguTec’s nano-crystalline coatings offer excellent edge retention and reduced tool wear. Aerospace customers need consistency. If a tool fails mid-process, it can result in thousands of dollars in costs. Its coatings ensure reliability and consistency, instilling confidence in the process.

“In the automotive industry, there is a shift from steel to lightweight materials, such as high-silicon-content aluminium alloys. Diamond tools provide the necessary wear resistance and precision. Automotive manufacturers are continually seeking ways to reduce weight while maintaining strength. Diamond coatings help us machine these materials efficiently," says Mr Cheon.

“In the defence industry, applications benefit from the arrival of diamond-coated tools, especially in machining radar components and missile guidance systems, which demand extreme precision. The defence sector requires flawless accuracy and surface finishes. A tiny deviation can mean the difference between success and failure. Our coatings help maintain that precision.”

To cater to the diverse demands of the marketplace, TaeguTec’s diamond-coated endmills are available in four different types. The RRFE Series eliminates delamination when machining CFRP while minimising vibration and cutting forces; this is complemented by the RCFE range, a geometry applied to multi-flute routers. With 6 to 12 flutes and a 15° helix angle, the RCFE is part of the DiaMill Series from TaeguTec. 

For finishing applications, the RCOM range of diamond-coated end mills, available in diameters ranging from 6 to 12mm, incorporates a left- and right-hand helix, commonly referred to as ‘up-down’ cutters in some sectors. The RCOM eradicates delamination with its unique geometry design. Also from the finish machining stable are the low-helix RDCF-type endmills, which complement the RCOM range and are the first choice solution for addressing concerns related to splintering and delamination on CFRP parts. 

TaeguTec has added the new RCDE multi-flute router to the DiaMill range, enhancing capabilities for drilling and slotting. Excellent for rough to semi-finish machining of carbon fibre components, the RCDE presents a geometry that excels at drilling CFRP and shoulder milling operations. All these DiaMill designations have been developed using TaeguTec’s TTD610 advanced nano diamond coating grade, which enhances machining stability and tool life while delivering excellent wear resistance with hardness exceeding Hv 8000. This gives all five end mills the highest possible thermal conductivity, impact resistance, and stability.

Additionally, TaeguTec’s innovations in indexable diamond-coated inserts are expected to drive further cost savings. This means customers will no longer need to replace an entire solid carbide tool. They can simply swap out an insert. 

The future of diamond tools 

TaeguTec is continuously improving its diamond coating processes. Ongoing research focuses on enhancing coating adhesion and developing multi-layer coatings to increase bonding strength between the substrate and the diamond layer. The company is also expanding its product lines, introducing diamond-coated indexable inserts for milling and turning applications. 

"Indexable inserts coated with diamond will give customers more flexibility while reducing costs in the long run," said Mr Jung. “To elevate production efficiency, we are fine-tuning the coating parameters to improve cost-effectiveness and scalability. We’re always looking for ways to optimise our processes and the performance of our tools across the entire spectrum of workpiece materials. If we can make a tool last even 20% longer, that’s a huge win for our customers.” 

Despite entering the market with diamond-coated tooling just eight years ago, TaeguTec’s extensive investment in in-house diamond coating technology and relentless innovation and development culture has positioned it as a leader in precision cutting tools. By leveraging advanced coatings, optimising geometries, refining its adhesion processes, and then combining this with its decades of expertise in R&D, the company continues to push the boundaries of tool performance. 

TaeguTec UK
www.taegutec.com