Introduction
The machining of difficult-to-cut materials is a challenging process. Materials such as titanium, stainless steel and Inconel are difficult to machine due to their high hardness and temperature resistance. In order to improve the machinability of these materials, various processes and coatings have been developed such as abrasive fluid jet machining, diamond coated tools, and various coating technologies. One of these new technologies is the application of coatings that allow for improved cutting performance. This paper will focus on the benefits of coating difficult-to-cut materials with a new type of coating that increases tool life and cutting performance.
Coatings for Machining Difficult to Cut Materials
The application of coating is a common method for improving the machinability of difficult to cut materials. Coatings are applied to tools and workpieces to reduce wear, increase strength, and reduce friction during the machining process. The most common types of coatings used for challenging materials include diamond coatings, metallic coatings, and ceramic layers.
Diamond Coatings
Diamond coatings have been used for many years as they are highly resistant to wear and can reduce surface contact friction during machining operations. Diamond coatings are typically applied through chemical vapor deposition (CVD) and physical vapor deposition (PVD) methods. They can also be applied through vacuum brazing and electroless plating.
Metallic Coatings
Metallic coatings are commonly applied to tools and workpieces for machining difficult-to-cut materials. These coatings include titanium carbonitride (TiCN), titanium aluminum nitride (TiAlN), and chromium nitride (CrN). These coatings are applied through physical vapor deposition (PVD) methods to improve the abrasion and oxidation resistance of the tools and workpieces.
Ceramic Layers
Ceramic layers are also used to increase the strength and reduce the wear of tooling and workpieces during the machining process. Commonly applied ceramics include aluminum oxide (Al2O3) and titanium dioxide (TiO2). These coatings are usually applied through physical vapor deposition in order to produce a tougher coating that can withstand higher temperature and pressures.
New Coatings for Difficult-to-Cut Materials
Recently, new types of coatings have been developed to address the machinability of difficult-to-cut materials. These coatings are designed to improve tool life and cutting performance by reducing surface contact friction, increasing heat transfer away from the cutting zone, and increasing abrasion resistance.
One of the coatings is called Geoxan. It is a combination of two different phases; a nanostructured alumina barrier layer and a nanostructured titanium oxide (TiOx) lubricant layer. The Geoxan coating is applied through physical vapor deposition and is then heat-treated for increased durability.
This coating is designed to reduce surface contact friction. The alumina barrier layer prevents metal-on-metal contact between the tool and workpiece, while the TiOx lubricant layer reduces the coefficient of friction and increases the chip flow during machining. The result is reduced cutting forces and improved surface finish. Additionally, the coating also increases thermal conductivity and can aid in heat dissipation during machining.
The Geoxan coating is applied to both the tool and the workpiece. Tests have shown that the coating improves tool life up to 500% and machining performance up to 200%. The coating has also been found to reduce cutting forces and improve surface finish.
Conclusion
In conclusion, coatings for machining difficult-to-cut materials such as Titanium, stainless steel and Inconel have been developed in order to improve cutting performance and extend tool life. The Geoxan coating is a new type of coating that has been found to be highly effective in reducing surface contact friction, increasing thermal conductivity, improving chip flow and increasing heat dissipation. Tests have shown that the coating can improve tool life up to 500% and machining performance up to 200%. The Geoxan coating is a promising technology that has been proven to significantly improve the machinability of difficult-to-cut materials.
