How to Select Ceramic Cutting Tools?

Ceramic cutting tools are mainly used for high-speed cutting of ordinary steel and cast iron which cannot be machined by cemented carbide cutting tools and machining of difficult to machine materials.

Each kind of ceramic cutting tool has its specific processing range.

1. Selection of ceramic cutting tools

(1) Alumina based ceramic tools are suitable for processing all kinds of steel and cast iron, as well as copper alloy, graphite, engineering plastics and composite materials.

Steel processing is better than silicon nitride based ceramics.

However, because its matrix contains Al element, it has a large affinity in processing aluminum and aluminum alloy, and the tool will have a large bond wear and diffusion wear, so it is not suitable for processing aluminum alloy.

Similarly, the “black” ceramic cutting tools of Al₂O₃/TiC and Al₂O₃/ (W, Ti) C contain Al and Ti elements, which have great affinity in processing aluminum and aluminum alloys and titanium and titanium alloys, so they are not suitable for processing aluminum, titanium and their alloys.

SiCw particles or whiskers SiCw toughened Al₂O₃ ceramic tools show excellent cutting performance when machining nickel base superalloys, pure nickel and high nickel alloys.

However, when machining steel parts, SiCw is easy to react with Fe in the steel under high cutting temperature, which reduces the original hardness and wear resistance of SiCw whiskers, weakens the bonding strength between whiskers and matrix, and causes sharp wear of tool materials.

Therefore, Al₂O₃ ceramic tools toughened by whisker SiCw are not suitable for machining steel and cast iron.

(2) The fracture toughness and thermal cracking resistance of Si₃N₄ based ceramic tools are higher than those of alumina based ceramic tools, which are widely used in the machining of cast iron and nickel based alloys.

The Si₃N₄ based ceramic tool mainly produces abrasive wear when cutting cast iron at high speed, and chemical wear when cutting carbon steel at high speed.

Due to the large affinity between Si3N4 and Fe and the mutual diffusion between Si and Fe, Si₃N₄ based ceramic tools are not suitable for high-speed cutting of iron, carbon steel and other materials.

Si₃N4 based ceramic tools are most suitable for high-speed machining of cast iron and superalloys.

Sialon ceramic cutting tools are most suitable for processing all kinds of cast iron (gray cast iron, nodular cast iron, chilled cast iron, high alloy wear-resistant cast iron, etc.) and nickel base superalloys.

They are not suitable for processing steel.

The key points for correct use of ceramic cutting tools are:

(1) The accuracy, rigidity, vibration of the machine tool and the clamping firmness of the tool to prevent damage and edge collapse.

(2) According to the properties and characteristics of the processed materials, the types and brands of ceramic materials shall be correctly selected.

(3) In order to exert the compressive strength of ceramic tool materials, ceramic tools generally adopt negative rake angle (-5 ° ~ -12 °).

(4) In order to utilize the heat resistance and wear resistance of ceramic tool materials, larger cutting parameters can be used as much as possible.

2. Grade and performance of ceramic cutting tools from various manufacturers

See table 2-38 for ceramic tool grade of each manufacturer.

Table 2-38 ceramic tool grade of various manufacturers