The working principle of shot blasting machine:
Shot blasting is a shot blasting surface treatment method that has been applied in developed countries in Europe and America. The world’s first shot blasting equipment was born 100 years ago, and it was first used in various metal or non-metal surfaces to remove impurities, oxide scale, and increase roughness. After a hundred years of development, the shot blasting process and equipment have become quite mature, and its application has not only been in various heavy industry factories. With the birth of the world’s first horizontally mobile shot blasting equipment in the United States, BLASTRAC, its application fields have rapidly expanded to concrete surface coating treatment and ship deck metal surface treatment, and directly lead the industry’s standards Formulate and industry construction method specifications.
With the continuous improvement of Baretech shot blasting equipment and mature technology, shot blasting technology and equipment have entered the fields of road maintenance, bridge construction and airport maintenance in developed countries in Europe and America. However, China’s application in this area is still very small. Only a few projects have used shot blasting processing technology, and there is still a blank in the waterproof coating of highways, municipal roads and concrete bridges. Gui Shi Di (GSD) hopes to use this article to introduce this new shot blasting process to colleagues in the maintenance and construction of highway and bridge engineering, and hopes that this new process and technology will be promoted.
1. Shot blasting process and working principle of shot blasting equipment
Shot blasting means that the shot material (steel shot or sand grain) is projected onto the working surface at a high speed and at a certain angle by a mechanical method, so that the shot material hits the working surface, and then cleaned by the airflow of the matching vacuum cleaner inside the machine , The technology of recycling the pellets and the cleaned impurities separately, and making the pellets reusable. The shot blasting machine is equipped with a dust collector, which can achieve dust-free and pollution-free construction, which improves efficiency and protects the environment. Shot blasting machines can be divided into three types according to their walking forms: hand-push type, vehicle-mounted type and self-propelled type.
During the operation of the shot blasting machine, by controlling and selecting the particle size and shape of the shot, and adjusting and setting the walking speed of the machine, the shot flow rate is controlled to obtain different shot strengths and different surface treatment effects.
1.2 Control of the quality of surface shot blasting
The shot blasting process and shot blasting equipment use three parameters to control the surface condition after treatment according to the different surfaces to be treated. Choose the size and shape of the pellets; the walking speed of the equipment; the flow rate of the pellets. The above three parameters cooperate with each other to obtain different treatment effects and ensure the ideal roughness of the surface after shot blasting.
For example: using S330 steel shot, flow rate 10A, processing C50 concrete surface, it can reach a roughness of 90; processing asphalt surface can remove the oily layer while reaching a roughness of 80; when processing steel plates, it can reach the cleanliness standard of SA3.
Roller-type shot blasting machine: It uses a high-speed impeller to throw projectiles to the castings and forgings that are constantly turned over by the roller to remove oxide scale, so that the surface of the workpiece can be uniformly cleaned, showing the original metal color.
Crawler shot blasting machine: the workpiece is loaded by high-strength wear-resistant rubber track or manganese steel track, and the high-speed projectile is thrown on the track by the shot blasting device to achieve the purpose of cleaning.
Rotary shot blasting machine: The surface of the workpiece is hit by a uniform steel shot through the frequency conversion shot blasting machine, and the coverage rate of the steel shot on the surface reaches more than 98% to achieve the strengthening effect.
Hanging chain stepping shot blasting machine: adopts multi-station fixed-point projection cleaning method to remove the sticky sand and oxide scale on the surface of the casting, so that the casting reproduces the metal color.