Stone World

Fabrication case study: Automated enhancement of granite slabs

April 9, 2002
Marmi Lanza of Verona, Italy, has implemented equipment to automatically apply resin and fully polish granite slabs. The slabs are treated with epoxy resin, which is manufactured by Tenax to reinforce and protect the slabs, in conjunction with a superficial treatment named Pectro applied at the end of the polishing process to hide small imperfections naturally present in the granite. In addition, the company also reports that the resin enhances the natural appearance of the stone.


Buffing units on the machine bring out the polish of the stone.
Given its rich history in stoneworking, the Verona region of Italy has long been home to innovations in stone fabrication. Fabricators in the area have found new methods and improved ways of implementing older procedures. One such case can be found at Marmi Lanza, which has invested in a new line to automatically apply enhancing resins to stone slabs.

The epoxy resin, which is man-ufactured by Tenax, is used to reinforce the surfaces of the slabs. The company also uses Pectro, another product manufactured by Tenax. This product is applied at the end of the polishing process to hide small imperfections naturally present in the granite slabs. The company also reports that both treatments enhance the natural appearance of the stone.

After rough slabbing of the blocks, the slabs move through a Gaspari Menotti slab polishing line that brings the surface of the slabs to a 220-grit honed finish. Then, the slabs enter a massive drying unit that removes any trace of water from the slab. The

unit places the slabs within an environment which is actually drier than the ambient air humidity, which allows for maximum efficiency in applying the resin.

From the drying unit, the slabs move to a machine that automatically reads the size of the slab and sprays the proper amount of resin. The spraying application takes place within a vacuum in the machine, which ensures that no air will enter the operation. After the resin is applied, it enters a second heating/drying unit, which speeds the reaction time of the resin with the stone.

Finally, the slabs move on to a PGM 2200 20-head slab polishing unit from Gaspari Menotti for processing from a 220-grit hone all the way to a final polish. Both units are equipped with diamond abrasive products from Tenax.

The factory can process a total of 2,500 square meters of slab material in two shifts (15 hours of work). A total of only three people, who monitor overall quality control, are required to oversee the operation. Operation intervention is even minimized at the polishing lines, because they are diamond technology and do not need to be replaced every few hours like conventional abrasives. According to Tenax, an abrasive head is replaced every one or two days.