These are brushes made up of filaments arranged around an inner metal ring, and pressed between two ferrules that are also metal (see Figure). The result is a thin disc-shaped brush with a flange and circular hole. The main feature of the rings is modularity. In fact, they can be used individually, but more often they are mounted on a shaft alongside each other to form a roller brush. The density of the roller can be modified by placing suitable spacers between the individual rings. The rings are simple and very light elements, useful when a small diameter and particularly compact roller is required. However, it should be noted that the pressing operation does not allow for tight mechanical tolerances or absolute uniformity of the filament. The dimensional accuracy of the ring is therefore lower than that of a similar punched element.
Ring brushes are used for :
- Thin brushing elements (4-7 mm)
- Small compact rollers
- Rollers where interchangeability of brush elements is required
The outer diameter of the rings is theoretically not limited. However, it must be taken into account that, as the ring has a relatively small metal core, very long filaments tend to bend. In practice, the maximum diameter can be considered to be around 500 mm with very large filaments.
The minimum diameter is a function of the size D3 of the ferrule, which can be seen from the table with reference to the figure. The values for thickness S are indicative.
Ring brush dimensions (mm)
The special feature of the brush is that the work surface is made up of millions of individual elements, which are the ends of the individual filaments.
This gives the brush an adaptability that no other element, however deformable, can have.
It depends on various factors. In a nutshell, it can be said that 2 mm is a good compromise. The important thing is that the filaments of the brush work “at the tip” and not on the side.
Depending on the materials used and the dimensions, there is a tensile limit load that a single bunch can withstand.
Beyond this limit the bunch comes off, therefore the brush must be calculated according to the use. This limit can be greatly increased by building “sewn” or “tied” brushes by hand, where a continuous steel wire is placed instead of a single anchor element.
Diagrams that answer this question can be found on page 23 of our catalogue.
It can only happen if the brush has a manufacturing defect, like any other type of object (e.g. a roller made with silicone flakes, one of which is defective and breaks).
When it is important that no contamination occurs, it is advisable to use synthetic (non-natural) fibers with a diameter greater than or equal to 0.15 mm.
Virtually all degrees of hardness can be had, from very soft to very hard. In fact, the hardness is given by the combination between the diameter of the filament, its free length and the density of the bunches.
Of course, we can provide FDA or FOOD GRADE certifications and filament traceability.
Unfortunately not, as it is the machine + brush assembly that must be ATEX certified, not just the brush.
It is however possible to provide the materials that the certifier requires, eg. conductive bases, conductive filaments etc …
Generally speaking it is possible, but it is necessary to evaluate if it is economically convenient, and it is not always. Furthermore, in the case of a punched brush, it is not advisable to regenerate the brush more than twice in order not to reduce the holding of the bunches.