Spotlight

Mirror finish porcelain according to BMR

16/04/2020

Lapping process evolution: "Sea Effect" vs "Lake Mirror Effect". A slightly rippled reflection on the tile can be a stylistic choice and it is not linked to the quality of the processing, but to the flatness of the tile surface. BMR’s LevigaPlus are already prepared to create slightly wavy effects (Sea Effect) or absolutely planar (Lake Mirror Effect).

Claudio Avanzi, BMR (Scandiano, Italy)

BMR upholds its leadership in the ceramic end-of-line segment, developing cutting-edge technologies both for the squaring process, and the polishing and lapping process. The affirmation of the slabs on the main international markets has also been addressed by BMR with a dimensional and movement flexibility of its machines that allows it to work both the large size and the traditional 600x600 mm size.

A huge advantage in plant engineering, allowing it to obtain multiple squaring and lapping services in a single line. This versatility is further developed for the lapping process in the ability to create different levels of mirroring, up to obtaining the "lake mirror" effect, or the perfect mirroring, without any deformation.

In fact, depending on the flatness of the tile surface it is possible to have slight deformations that make the reflection on the tile slightly rippled.

This effect is not linked to the quality of the processing, since it deals with surfaces with  planarity differences amounting to hundredths of millimetres: a value that is imperceptible to the human eye, but that is evident in the reflected image and that can be managed according to the desired level of lapping.

BMR’s LevigaPlus modern polishing machines are already prepared for these effects as they can be set up with different spatula heads, and carry out different processes both on technical monolithic or double loading lapped porcelain stoneware, and on glazed porcelain stoneware with the application of crystalline layers that allow removal of 0.5 mm.

If you want a non-specular shiny surface, lapping will be done with tangential spatula heads - e.g. PLT6 - which eliminate the surface micro-grooves with a polishing effect.

The “lake mirror” effect is obtained by installing, in the first lapping positions, from 4 to 6 satellite heads (like the PLS5) or cylindrical heads (like the PCS), whose characteristics can be recognized in the rigidity and precision of the mechanisms. This allows a perfectly flat surface, to which the subsequent tangential spatula heads (like the PLT6) will only add the elimination of the surface micro-grooves with a polishing effect.

Premise: sizes starting from 1200x1200 mm do not allow thickness calibration.
Slab technology does not require thickness calibration.
GLAZED PORCELAIN STONEWARE TECHNICAL PORCELAIN STONEWARE
LEVIGA 1 Light polishing on crystalline or glaze mixed with crystalline Light polishing
Surface removal 0.2 ÷ 0.5 mm 0.2 mm
Gloss 65-70 60-65
LEVIGA 2
Lapping as a final surface treatment cycle shows us that polishing is already included.
Lapping Lapping
Surface removal 0.1 mm 0.1 mm
Total removal 0.3 ÷ 0.5 0.3 mm
Final gloss 70 ÷ 80 65 ÷ 70
Traditional technology tile
“Lake mirror” effect
Minimum removable crystalline thickness 1.0 mm Removal
0.6 ÷ 0.8 mm
Probable need for thickness calibration
Slab technology tile
“Lake mirror” effect
Minimum removable crystalline thickness 0.5 mm Removal
0.2 ÷ 0.4 mm

BMR is also able to carry out subsequent surface treatment processes: generally, the first is that of acid pickling, carried out to exclude any shading deriving from washing after laying with aggressive detergents. Depending on the type of surface, BMR offers two different solutions for subsequent surface treatment: TopCoat (which preserves the original gloss) and SuperShine, a high-tech treatment machine that carries out a thermo-mechanical processing capable of increasing by 30 points and more the degree of Gloss coming from lapping.