Are Ceramic Inserts Expensive Compared to Carbide Inserts?
Ceramic inserts are 2-3 times more expensive compared to carbide. However, due to metal removal rates achieved the cost per edge is less than carbide.
Do You Need a High Power or High Speed Machine Tool?
Modern machine tools have no issues with ceramic inserts when turning, grooving or profiling but when milling, the power pulled needs to be calculated and compensated with cutter diameter.
Can I use Standard Tool Holders for Ceramic Turning Inserts?
In short – NO. When turning, it is recommended to use ceramic specific tool holders. Normal negative carbide tool holders have a top and side rake of -5°, whereas when machining with ceramics it is recommended (on materials under 45 HRc) to use tool holders with -5° top rake & -10° side rake. Also, when milling, due to high RPM, holders balanced in excess of the cut RPM must be used.
How Long Do Ceramic Inserts Last Compared to Carbide Inserts?
On average, when machining HRSA’s with ceramics the in-cut time is between 5–8 minutes for turning and 3–5 minutes for milling. The metal removal rates are far greater than carbide with up to a hour cut time.
Grades of ceramic insert available
Al2O3 (commonly known as a white ceramic) is suitable for both roughing and finishing applications for turning & milling cast iron.
Al2O3 + Tic Composite Ceramic (commonly known as black ceramic) is suitable for machining hardened materials up to 65 HRc.
Si3N4 Silicon Nitride inserts have high toughness and are suitable for machining Cast Iron (Generally grey in colour).
Whisker Ceramics are made up of silicon carbide whiskers (SiCw) which dramatically give strength to the ceramic matrix making it ideal for machining Heat Resistant Alloys and allows coolant to be used (Green in colour).
SiAION (Sialon) Ceramics are one of the latest advancements in ceramic insert technology. This has enhanced chemical stability and is ideal for machining Heat Resistant Super Alloys.