Types of Abrasives Used in Sandblasting Processing

1. Introduction to sandblasting equipment

Compressed air is the most commonly used medium in sandblasting machine to make loose abrasives impact the surface of workpiece violently for the purpose of cleaning and finishing. The most commonly used equipment for sandblasting process is the sandblasting machine with the aid of compressed air. This kind of sandblasting machine is divided into open sandblasting machine and close-loop sandblasting machine. In addition, there is a kind of airless sandblasting cleaning machine used for airless sandblasting cleaning and processing.

Sandblasting machine mainly includes four parts: device for storing and mixing sandblasting abrasive, dry gas supply device, nozzle, dust and abrasive collector.

When the open sandblasting machine is working, the operator will suffer from the dust and dirt from waste materials and surface grinding impurities. It is for this reason that the sandblasting process is usually limited to a more spacious outdoor area or a place with good ventilation conditions on the processing site. Of course, it is more suitable to have a special sandblasting workshop for processing.

The close-loop sandblasting machine can prevent the harm of sandblasting to operators and surrounding environment. The external spraying device of the close-loop sandblasting machine is connected with an effective vacuum return system, which can collect waste abrasive, dust and debris.

2. Types of sandblasting abrasives

The types of abrasives used in sandblasting process are natural mineral abrasives, artificial mineral abrasives and metal particles. Natural mineral abrasives include silica sand, flint and quartz sand; artificial mineral abrasives include corundum and silicon carbide; metal abrasives include metal shots or balls, metal chips, metal particles and non-ferrous metal abrasives.

The problems to be considered in the selection of abrasives for sandblasting process include the required efficiency and precision of machining, the ability to cut into special parts of the workpiece surface, the avoidance of pollution and the recovery of abrasive particles required by recycling.

Airless sandblasting (sand peening) cleaning process is carried out by special equipments. The corresponding equipment, airless sand blasting cleaning machine, uses rapid rotation sandblasting impeller to control centrifugal force rather than compressed air to make the spraying abrasive impact the surface of workpiece for processing. The measured abrasive from the hopper continuously flows in the mode of abrasive flow to the center of the rapid rotation impeller device. Due to the centrifugal force, the abrasives impact violently onto the exposed surface of the workpiece in accordance with the control direction.

Airless sandblasting machine is suitable for the cleaning and processing of the workpiece whose surface is covered with an extremely strong adhesive layer, which must be completely removed without damaging the matrix of the material. These attachments usually refer to molding sand and core sand on castings, iron scale on hot-rolled metal surface (rolled iron scale), oxide skin on heat-treated workpiece surface, large burrs on stamping parts, rust generated during storage or use, etc.

The most common abrasive used in airless sandblasting cleaning machine is steel shot, which is made of hardening carbon steel. It has the advantage of negligible wear and long service life. When it is applied to internal surface processing, the resilience force of the steel shot can be used as a removal force, even for surfaces that cannot be directly impacted. The steel shots used in sandblasting cleaning can also produce hammering effect and improve the fatigue life of machined parts. For the parts affected by stress, it is more suitable to use sandblasting process for cleaning and processing.