Bristle Blasting

from Wikipedia, the free encyclopedia

Bristle blasting or German wire tensioning blasting is a process for processing metallic surfaces using a rotating belt equipped with wires. It is used to remove corrosion , scale , impurities or surface coatings and to achieve a defined surface cleanliness and roughness.

The term bristle blasting suggests a relationship to sandblasting (Engl. Sand blasting ) out. In contrast to surface treatment by ordinary steel brushes, the bristles (are bristles ) additionally accelerated here before impinging on the material, so that a similar effect as the surface treatment with a blasting agent formed.

principle

A belt equipped with wires or a flexible ring brush rotates on a tool head of a pneumatically or electrically operated drive unit.

During the rotation, the bristles are briefly held back by an obstacle, the so-called acceleration rod. In doing so, they are bent back in the anchored carrier material and thus tensioned. When the bristles pass the accelerator rod, they snap forward again. The potential energy of the bent bristles is converted into kinetic energy, so that the bristles hit the surface of the machined workpiece with increased intensity. The impulse of the bristles is comparable to that in blasting processes .

When the surface is hit, corrosion products, scale or coatings are removed and a small crater is created on the surface that roughen the material .

technology

In contrast to simple steel brushes or wire brush belts, the wire bristles are not anchored rigidly. Rather, the U-shaped wire bristles hang elastically in a polyamide tape . Due to the flexible anchoring, the fast forward and the angled shape of the wire bristles, the bristles hit the material directly with their tips, while the bristles of ordinary steel brushes tend to slide past the material to the side. When the bristle tips rebound, small craters are created on the surface instead of the usual grinding pattern in the form of grooves.

application areas

Bristle blasting is mainly used for the surface preparation of metallic surfaces before the application of corrosion protection agents or other coatings .

On steel surfaces, bristle blasting usually achieves a degree of purity of around Sa 2 ½ to Sa 3. As with normal brushing as well as with needle de-rusting , the surface roughness is generated as a secondary roughness , i.e. H. it overlays any primary surface structure that may be present.

The working speed is usually slower than with conventional blasting methods and is around 1.1 m² per hour, depending on the material and nature of the surface. The process is therefore mainly used for selective work and repairs. Or where sandblasting is not possible due to legal or safety regulations. Areas of application include the oil and gas industry (cleaning and roughening of weld seams ), as well as repair work and maintenance of steel structures on offshore systems in bridge, ship and hydraulic steel construction .

See also

Individual evidence

  1. Piyush Khullar, Robert J. Stango: Fundamentals of bristle blasting Process for Removing 2009 .
  2. ^ Neil Wilds: Bristle Blasting as a Method for Surface Preparation , 2009.
  3. Monti MBX Bristle Blaster, High-Speed ​​Video on Youtube .
  4. Robert J. Stango, Ph.D., Raymond A. Fournelle, Ph.D., Jorge A. Martinez, and Piyush Khullar: Surface Preparation of Ship Construction Steel / (ABS-A) via bristle blasting process , of 2010.