Sandblasting is a technique used in the industrial sector to clean parts and leave them ready for a subsequent coating (of paint or any other substance). Therefore, sandblasting is the action of spraying surfaces with micro abrasive particles thrown at a high adjustable speed.
This abrasive blasting exerts an effect similar to sanding, which leaves the surface of the parts with a non-reflective satin appearance.
Sandblasting is one of the safest and cleanest procedures for cleaning and recovering industrial parts and removing rust from them. This process is also known as shot blasting, sandblasting or sandblasting.
Although it is said “sandblasting” strictly speaking, it is not sand that is used, but micro structures or glass beads, being one of the most effective abrasives for cleaning parts.
Sandblasting with glass microstructures is the most suitable process for cleaning and treating pieces of stainless steel, aluminium and other non-ferrous alloys, and even wood or stone surfaces.
Furthermore, it is environmentally friendly because glass microstructures are inert, made from flat and treated glass; they do not contain any carcinogenic or toxic elements and do not generate ferric contamination.
The main feature of sandblasting is that no liquids are used, i.e. it is a dry process that leaves virtually no residue, apart from dust.
This guarantees a very effective cleaning, and an extremely efficient waste management, as the glass microstructures can be reused several times.
However, this process must be carried out at specific sites, with equipment specially designed for sandblasting, and operated by qualified personnel.
Characteristics of glass microstructures
Its chemical composition is SiO2 (70-73%), Na2O (13-15%), K2O (0.2-0.6%), CaO (7-11%), Mg (3-5%), (0.5-2%). They have a hardness of 6 Mohs and a density of 2.5g/cm3. The colour is white and the grain size is between 100/200 microns.
Sandblasting equipment with specific requirements is needed. Generally, sandblasting cannot be done outdoors. Therefore, a specially designed space is required for sandblasting with glass micro structures.
It must be an isolated space to avoid air pollution due to volatile particles thrown up by the product when the machine is operated.
This space is called the “sandblasting room”, and regularly the companies that offer sandblasting have not only the sandblasting machines but also these airtight rooms where the pieces can be worked correctly, complying with all the regulations.
The sandblasting equipment consists of a flexible and reinforced hose, with a length according to the needs of the work and which allows the operator to reach the whole surface and move freely.
The hose ends with the application gun, whose nozzle can be adjusted to fine tune the sand output pressure; the pressure varies from 2 to 10 bars, depending on the material and the finish being applied.
On the other hand, the sandblasting equipment is also equipped with special suits for the operator, which guarantees his safety throughout the process. It is a one-piece suit made of resistant material, and a mask that protects you from the abrasive blast.
Although sandblasting for cleaning purposes is an environmentally safe process, due to the abrasives used, operators must be protected from possible injuries, which is why the entire procedure is carried out under strict safety conditions.
On the other hand, blasting machines are special machines that allow for the adequate regulation of the sand output, and are a fundamental part of a sandblasting equipment; it is not necessary to change the nozzles, as they incorporate a remote controller that controls and adjusts the abrasive flow.
As already mentioned, sandblasting allows for the reuse and recycling of the material. A cyclone filtering is carried out to remove impurities and the pure abrasive is separated from any paint or metal residue that has resulted from the process.
The environmental impact is therefore reduced to a minimum.
Sandblasting for cleaning can be applied to various industries and processes, which are mentioned below: cleaning of INOX and pickling of welds to remove calamine; satin-finishing and matting of parts, cleaning of parts to homogenise surfaces, correction of defects, pre-treatments for anodising, sandblasting of aluminium or gentle cleaning of turbos, engines, moulds and other parts.
In addition, the industrial sectors in which sandblasting for cleaning purposes is applied are varied.
Sandblasting is useful for deburring when manufacturing housings and various components.
Sandblasting is effective for cleaning drills, cutters or reamers, as well as for removing burrs on cutting wires – where it increases resistance – and cutting erosion on various treated metal tools.
Sandblasting is highly effective for cleaning pump parts, valves, pump shafts, compressors, pistons, fans, distillation tower elements, heat pipes, electrical parts and other components and instrumentation required in the industry.
Sandblasting provides a surface finish on surfaces and equipment, eliminating machining marks and preparing them for subsequent enamelling or coating.
Sandblasting is effective in eliminating corrosion at the contact points, due to the action of chlorides.
The procedure is used to clean cast models and prevent corrosion and cracking due to mechanical stress; this prolongs the life of parts exposed to stress.
Sandblasting is essential for cleaning ovens and instruments in contact with materials, making them suitable for agricultural and human consumption.
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