Share this page by mail Can rigid composites be machined with a CNC machine?
Yes, the inorganic composites produced by Final Advanced Materials can be CNC machined. Machining of calcium silicate-based (CaSiO₃) refractories or derived materials of the insulating boards type involves specific aspects relating to their low density, high porosity and low mechanical cohesion. Although these composites are not hard, they pose a high risk of scaling and crumbling: loads must therefore be minimised, and stripping of material must be avoided. The resulting powder is very abrasive and it is therefore essential that a dust extraction system is installed on your machinery. We can machine these materials in our production shop.
Calcium silicate boards have a low density (200–1,000 kg/m³), low thermal conductivity (~ 0.05–0.35 W/m·K) and high temperature resistance of up to 1,000°C. They are used as structural insulators.
Mica boards (phlogopite or muscovite) have great dielectric strength (>20 kV/mm) and temperature resistance up to 500–1,000°C, depending on the type. It must be permanently compressed between 2 other boards to preserve its mechanical integrity (the silicon binder degrades at high temperature). Use of mica composite requires particular attention: please contact Final Advanced Materials for more information.
For continuous use at 1,000°C, Final Advanced Materials recommends composites made of ceramic fibres or calcium silicate. These materials have a low thermal conductivity (~0.08–0.35 W/m·K) and high dimensional stability. Nanoporous composites can go as low as 0.02–0.04 W/m·K but are more mechanically fragile. The choice depends on your requirements: thermal insulation or mechanical resistance. We require a complete description of the application and of the stresses before we can recommend the most suitable product.
Final Advanced Materials' high-temperature composite panels have resistances ranging from 1 to 40 MPa when compressed, depending on the density.
Light insulating materials (fibres and microporous materials) are limited (~1–5 MPa), while denser composites (reinforced silicate, zirconia) can resist up to 10–20 MPa and even as high as 40 MPa in the case of a calcium silicate with a density of 1,300 kg/m3.
Specifically: all inorganic composites which are capable of withstanding exposure to high temperatures (>300°C) have no elasticity and are therefore quite fragile.