Mechanical and surface finishing

The newly produced casting, now decored and with risers removed, has a particularly rough surface morphology (due to the fact that the mould is made up of sand grains), often with sand and binder residue still “stuck”. Once the removal treatments have been carried out to eliminate the casting appendages, additional operations are required in order for the casting to meet the design requirements (geometry and surface characteristics). One of the most common treatments is sandblasting, which allows the surface of the casting to be cleaned of impurities and residue, albeit preserving a certain roughness.

It is common for “burrs” to form in castings due to the infiltration of liquid cast iron, for example, in the space between the upper and lower flask. Burrs are therefore a geometrical irregularity that must be removed (deburring) using an angle grinder or by turning operations.

Super Satisfying Sand Blasting Session – RRC Restoration

Subsequently, if requested, all the mechanical finishing operations are carried out, necessary to remove any machining allowances and obtain the desired tolerances and roughness according to the design.
The main types of mechanical machining that can be performed on cast irons are explained at: Mechanical machining of cast irons

Cast irons normally have good machinability due to the presence of graphite, which for all intents and purposes acts like a solid lubricant, thus facilitating machining and cutting. In many cases, the thermal conductivity properties of graphite also allow dry mechanical machining, without the use of cooling fluids.

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