In ceramic pressing, mould cleaning is not only about removing residual material. It is about keeping constant the way in which the piece is formed, released and sent to the following stages. Even a minimal deposit, if it always remains in the same area, can alter contact, modify the surface, create repeated imperfections or force manual interventions that interrupt the rhythm of the press. The issue is therefore not to brush harder, but to brush in the right way and with the same effectiveness cycle after cycle.

A solution that is too aggressive may seem effective in the first tests, because it quickly removes the visible residue. But if it wears the mould, leaves marks, changes the surface or requires constant adjustments, it is not a real industrial solution. In ceramic lines, cleaning must be stable, predictable and compatible with machine times, powders, humidity, mould geometry and the quality required from the piece. Contact pressure, fibre type and movement repeatability therefore become more important parameters than abrasive capacity alone.

Ceramic residue is not always the same

The material to be removed may appear as dry powder, a more compact deposit, an adhering particle, a localised trace in corners or an accumulation along a passage area. Its consistency depends on body composition, humidity, pressure, cycle, temperature and environmental conditions. A brush that works well on light residue can clog or lose effectiveness on a tougher deposit; a rigid brush can remove the material, but transfer too much energy to the mould.

The position of the residue also matters. Flat surfaces, edges, recesses and areas close to detail elements do not require the same contact. If the brush does not follow the real geometry or if it works with excessive pressure only in some areas, cleaning becomes irregular. The result can be paradoxical: some areas are over-stressed, while others remain dirty. Cycle quality depends on the ability to maintain homogeneous contact where needed and more controlled contact where the geometry is sensitive.

Contact pressure: enough to clean, not enough to damage

Pressure is one of the most delicate parameters. If it is too low, the brush merely skims the residue; if it is too high, filament wear increases, the mould can be stressed and part of the material may be compacted instead of removed. Excessive pressure also never comes without consequences: it absorbs more energy, generates more friction, can deform the behaviour of the brush and reduce component life.

Pressure control should not be left only to the initial adjustment. With wear, the filaments change their free length and perceived stiffness; what was correct with a new brush can become insufficient after many cycles, or may be compensated with adjustments that are too drastic. For this reason, the system must allow repeatable and measurable adjustments, especially when several operators work on the same line or when moulds change frequently.

Choosing the fibre by behaviour, not only by hardness

The choice of filament cannot be reduced to the question “hard or soft”. Materials are needed that can withstand the cycle, remove the residue and maintain a constant behaviour. Synthetic fibres, natural bristles and metallic filaments respond differently in terms of flexibility, elastic recovery, abrasion resistance, ability to discharge material and behaviour in the presence of humidity or fine powder. The correct solution always depends on the relationship between mould, residue and intervention frequency.

Cylindrical technical brushes are often suited to applications in which cleaning must take place along a surface or a repeated path, because they allow rotation, density, filament material and tuft arrangement to be controlled according to the line. In a ceramic mould, however, the shape of the roller must be considered together with the position of the deposit and the possibility of conveying the residue. Removal is not enough: the material must not return to the mould or be distributed over another critical area.

Cycle repeatability and piece quality

Cleaning becomes truly effective when it produces the same result over many consecutive cycles. A brush that works well only after expert adjustment, or only during the first hours, leaves the line exposed to variations that are difficult to interpret. In production, the right question is not whether the residue is removed in a test, but whether it is removed in the same way during a shift, after format changes, with a progressively worn brush and with environmental conditions that are not always identical.

Repeatability also has diagnostic value. If cleaning is stable, any defects in the piece can be traced more easily to other causes: body composition, pressure, mould wear, humidity or press adjustment. If cleaning is variable, it becomes background noise that confuses analysis. The risk is to intervene on the process when the problem comes from brush contact, or to replace components that are still usable because the defect appears to originate from the mould.

Integrating cleaning and maintenance

A brush for ceramic moulds must also be assessed from the maintenance point of view. If it retains too much material, it will need frequent cleaning; if it wears quickly, its behaviour will keep changing; if it is difficult to remove, operators will tend to postpone intervention. The fixing system, protection of supports, replacement options and management of removed residues all affect the real effectiveness of the solution.

A mature choice comes from tests carried out on the process, not from an abstract comparison between materials. The type of deposit, its formation frequency, the point where it accumulates, mould sensitivity, required speed and effect on the finished piece must all be observed. When these data guide the design, the brush does not only clean: it becomes a tool for keeping the cycle stable, reducing manual interventions and protecting the quality of ceramic production over time.

Tests, wear and stability over time

A well-designed test should assess not only the clean mould, but also the behaviour of the brush after a period of work. The first result can be misleading: new filaments, freshly completed adjustment and a carefully checked mould often give a better response than ordinary production will. It is necessary to understand how pressure, removal effectiveness and discharge capacity change when the component begins to wear.

Stability over time is especially important because mould cleaning affects repeated defects. If the brush gradually loses effectiveness, the department may not notice immediately. Pieces begin to show small imperfections, operators increase the frequency of manual interventions and the process becomes less readable. To avoid this effect, it is useful to define already during selection which signals indicate wear, when to intervene and which adjustments are allowed without altering brush behaviour.

Compatibility with mould changes also deserves attention. If the line works with different geometries, the cleaning component must maintain consistent contact or be replaceable quickly. A solution that is effective on one mould may not be enough for a department that changes format during the week. In that case, ease of mounting and repeatability of position become part of brush quality.

Finally, when evaluating the solution, it must be remembered that the removed residue does not disappear. If it remains near the moulding area, it can re-enter the cycle or settle on sensitive components. The brush must therefore be designed together with discharge direction, any extraction system and collection spaces. Effective mould cleaning is complete only when the material that has been detached is also managed consistently with the machine.