Process of Stone grinding and Polishing
There is different process in stone production, starting from quarry block sawing, block cutting to slab or tiles, stone polishing and then again stone cutting or engineering to finished products. Today we will discuss a polishing process in stone production.
Normally stone polishing starts with a calibration or rough grinding and then comes to find grinding and coarse polishing and fine polishing and comes to final polishing and cleaning. In between there may be resin filling.
For stone calibration, usually diamond metallic abrasive(such as diamond fickert for granite or diamond metallic Frankfurt for marble) is in use. Diamond is more aggressive in stock removal and more efficient for stone calibration to make surface more smooth and prepare for grinding and polishing. Magnesite abrasive stone also works for calibration, coarse grits such as 16#, 24# 36# and 46# are used for calibration. Compared to diamond metallic abrasives, magnesite stone is with silicon carbide as abrasive working materials, it is less aggressive and usually more polishing pressure in first few steps of calibration.
After calibration, it comes to stone grinding, different choices of abrasive is available now. Traditionally use magnesite abrasive stone, and now diamond bricks and resin bond abrasive also in promotion for longer life, these 3 different bond of abrasive tools are with different advantage. For granite grinding, no matter diamond fickert or resin fickert in use, it is suggested to use one of two sequence of 60#, 120# or 220# magnesite stone to prepare the surface. In between stone grinding process, using 36# to 320# abrasive tools, some use resin filling in between and some not, depends on production needs and natural of stones.
For marble polishing, 220# and 320# and 400# is intended to prepare for shinning. And it is suggested to use sharper abrasives to get good shinning. It may give less abrasive life, but it gives better polishing in return. Operators prefer long life abrasives 15 to 20 years back, thinking that long life abrasive will give less polishing cost, however, after introduction of idea of “sharper abrasives, less polishing cost” and the testing of sharper abrasives, operator increase polishing speed, hourly polishing square meters is increased and also polishing quality is better. As checking the water and electricity consumption, polishing cost is much less compared to abrasive cost increased and polishing quality is better.
After grinding, it comes to polishing, starting from 400# to 1200# for marble and up to 1500# or 3000# for granite polishing. And then the final polishing, for granite, Buff or LUX is in use and for marble, 5 Extra Yellow polishing stone and sponge cleaner pads are in use.
From calibration to final polishing, each grit sizes works its purpose and please remain in mind not to skip grit size too much and if possible, use more and more grit sizes if you have enough polishing heads. More polishing heads or more grit sequences in use, better polishing quality you will get.