Precision granite mechanical parts, including hollow bases, guide‑way substrates, gantry frames and inspection plates, feature ground datum working surfaces with micron‑ to nanometer‑level accuracy. Although these components are hard, they are distinctly brittle. The material delivers excellent compressive performance yet poor impact and shear resistance. Once corners, hollow‑window edges or datum surfaces suffer collision, chipping, corner breakage or local pits will occur. Such damages cannot be repaired through simple on‑site adjustment and will directly impair geometric accuracy. In severe cases, the whole part has to be sent back to the factory for re‑grinding. Many accuracy failures of granite parts stem not from manufacturing defects, but from transfer links such as handling, hoisting and assembly. Therefore, a complete anti‑collision protection procedure is critical to preserve the original accuracy of delivered granite parts.
Packaging and pre‑protection before handling serve as the first defensive line. Granite substrates shall never be transported in bare condition. All exposed datum working surfaces shall be covered with friction‑resistant protective films. Hard corner protectors shall be installed on high‑risk positions such as edges and the perimeter of hollow windows to fully wrap protruding ridges instead of simple spot‑type sticking. Note that hard metal shall not make direct contact with stone surfaces; rubber, polyurethane and other cushioning materials shall be adopted for isolation. Flexible cushioning material shall be filled inside packaging boxes to restrict component shifting and prevent collision between parts and hard internal box accessories during transportation. For large‑size granite hollow bases, self‑weight shall be taken into account. Support points of the box shall be set on rigid solid areas, and stress on thin‑wall sections of hollow windows is forbidden to avoid local cracking.
Hoisting and transfer represent high‑risk stages for collision accidents. Soft lifting slings are preferred for large granite components. Steel wire ropes and chains shall never be bound directly to stone bodies, for their high hardness will easily scratch edges and working surfaces during hoisting swing. Hoisting points shall strictly follow positions marked by the manufacturer and shall not be altered arbitrarily. Especially for hollow granite parts, lifting appliances shall not be hooked onto inner walls of hollow windows. Thin‑wall sections under hoisting tension may generate invisible micro‑cracks, which will gradually expand under equipment operating vibration and finally lead to accuracy failure. Before hoisting, check lifting tools for sharp burrs. Keep the whole hoisting process stable without abrupt start‑stop or large‑amplitude swinging. Clear metal toolings, bolts and tools along the moving path in advance to avoid scratching caused by swinging. When placing down components, do not drop stone corners directly onto metal tables. Lay integral cushion pads underneath and place parts gently.
Protection measures shall also be implemented during on‑site assembly. Do not pry packaging boxes forcibly with hammers or crowbars, as sharp tools may slip and scratch stone surfaces. Utility knives and plastic pry pieces are recommended for slow unpacking. Do not peel off all protective films of datum surfaces immediately after unpacking. Keep films intact until final assembly is nearly finished to avoid accidental collision of working surfaces by tools and components. Keep assembly areas tidy. Remove hard debris such as metal chips, bolts and gaskets from floors and workbenches. Hard particles trapped under granite parts will press pits into stone surfaces under compression. Operators shall not lean sharp tools against granite components. Wrenches, screwdrivers and other tools shall not be placed on datum surfaces, since falling tools are a common cause of surface pits.
Bolt tightening and component assembly also carry hidden collision risks. When installing metal accessories and modules, align positions slowly and forbid dropping them onto granite substrates, especially thin‑wall areas around hollow‑base windows which are highly vulnerable to chipping upon impact. Tighten bolts in strict accordance with torque specifications. Apart from preventing stress‑induced stone cracking, this also avoids lateral extrusion and collision caused by displaced assembled parts. If granite parts need temporary relocation during assembly, never drag or slide them. Dragging will scratch bottom datums due to friction with hard particles on tables. Use lifting equipment to lift components entirely for displacement.
Protection shall not be neglected even after assembly during equipment commissioning. Set up isolation barriers for granite components during peripheral construction or modification of other modules to prevent damage from falling welding slag and tools. For temporary shutdown, re‑install dust‑proof cushion covers for both dust prevention and impact resistance against accidental falling objects.
Never attempt on‑site self‑repair after collision damage occurs. In case of corner chipping or surface pits, do not grind or polish on‑site with angle grinders or sandpaper. Unprofessional field machining will destroy original flatness and geometric tolerances of datums. Mark damaged positions for minor collisions and contact the manufacturer for evaluation. Severe damage requires factory re‑grinding repair.
To sum up, anti‑collision protection for precision granite parts runs through packaging, hoisting, unpacking, assembly and commissioning. Unlike metal parts which can be simply polished after collision, granite components mostly suffer irreversible damage. Standardized operating procedures shall be adopted to avoid contact, impact and dragging by sharp hard objects. Only in this way can precision granite parts such as hollow bases and guide‑way substrates retain factory‑level high accuracy through to complete‑machine operation.