When selecting granite reference parts for precision equipment, many design engineers often have one question: granite features high hardness and brittleness. Can mechanically processed granite plates be fabricated with slots, holes and various special-shaped structures? Many customers hold the stereotype that granite can only be made into simple flat plates. Once components require grooves, through holes, counterbores or special-shaped profiles, they have to be processed separately and then assembled together. Joint seams and stress deformation caused by assembly will directly damage benchmark accuracy. In fact, with professional CNC mechanical processing technology, UNPARALLELED Group (Brand: UNPARALLELED®) can integrally complete slotting, drilling, step forming and complex special-shaped contour machining on one single granite blank without splicing, delivering monolithic granite components for precision equipment.
The processing difficulty of granite lies in its dense crystals and high hardness. Ordinary equipment tends to cause edge chipping, crystal peeling and cracks during machining, especially for deep holes, narrow grooves and thin-wall special-shaped structures. Slight deviation of processing parameters may lead to workpiece rejection. Traditional manual processing can only make simple shallow holes and basic grooves, while complex special-shaped structures are hardly achievable. This is the main reason why many people believe granite can only be manufactured as flat plates. Mechanical processing adopts CNC systems and special diamond cutting tools, together with layered low-stress cutting technology to overcome the machining challenges brought by granite brittleness and realize integrated forming of complex structures.
Slotting is one of the most common processing requirements for granite components, including shallow grooves, deep grooves, narrow grooves, T-slots, long guide grooves and more. These grooves are used for linear guide mounting, space avoidance for wiring, air channel forming for air bearings and reserved cooling flow channels. UNPARALLELED uses CNC gantry equipment for layered milling slotting. Instead of heavy cutting at one pass, it removes material step by step with small cutting depth and repeated tool paths to reduce cutting stress and avoid crystal chipping at groove edges. The verticality of groove side walls and flatness of groove bottom are controlled by programs. Tolerances of groove width and depth are manageable. The groove bottom can be finished by precision grinding synchronously to guarantee planar accuracy of the reference surface inside grooves. For sealed air channel grooves inside air pressure guide bases, inner walls will be polished and cleaned after slotting to reduce airflow turbulence and meet air supply requirements of air bearing systems.
Drilling covers ordinary through holes, counterbore holes, pre-embedded threaded holes, precision locating small holes and large-diameter deep holes, applied for equipment locking, locating pin installation and pipeline penetration. Thread tapping cannot be performed directly on granite. The standard solution is embedding stainless steel thread inserts inside holes for reliable threaded connection. During mechanical drilling, drill bits feed at constant speed with cooling and dust removal processes to suppress temperature rise and prevent microcracks on hole walls. Small holes can achieve micron-level position accuracy. Hole spacing consistency of multi-hole arrays is high, free from hole position offset and orifice chipping common in manual drilling. For multi-hole arrays on large granite plates, the CNC program plans all points at once to ensure positional accuracy of all holes relative to the benchmark, facilitating customers' overall equipment assembly.
Besides slotting and drilling, mechanical processing can realize many special-shaped structures, including height steps, inclined sections, curved contours, local thin walls and special-shaped cutouts. Many granite bases for optical and semiconductor equipment need reserved clearance positions for electronic components, mounting steps and special-shaped notches. The traditional solution is splicing multiple flat plates. Joint seams bring discontinuous reference surfaces. Dust easily accumulates at seams during long-term use and minor displacement deviation may even occur. UNPARALLELED's integrated mechanical processing directly mills and forms special-shaped contours from one whole granite blank. Components have no splicing seams, continuous and complete reference surfaces, more stable overall stress status and no hidden risks of misalignment or warping for spliced parts.
Of course, there are technical boundaries for special-shaped granite machining. Not all structures can be designed without limits. Overly thin thin walls, extremely narrow and deep grooves and large-span suspended structures carry fracture risks during processing and subsequent use. UNPARALLELED engineers conduct drawing review in advance and optimize special-shaped structural schemes according to granite material properties. Fillets, wall thickness and groove depth can be adjusted without impairing equipment functions to avoid processing risks and guarantee structural strength of components.
Substrate and pre-processing aging treatment form the foundation of integrated special-shaped machining. UNPARALLELED® black granite undergoes prolonged natural aging and constant-temperature stress relief to fully release internal blank stress. If residual stress remains high inside the stone, material removal during slotting and drilling will trigger stress release and cause plate deformation, invalidating flatness, hole and groove accuracy. After stress relief, blanks feature higher dimensional stability after cutting, slotting and drilling. Overall precision grinding is carried out after structural forming to ensure reference surface accuracy will not be damaged by subsequent cutting. The whole process is carefully scheduled: stress release by aging first, then CNC milling for slotting, drilling and special-shaped forming, followed by overall surface precision grinding, preventing subsequent cutting from damaging finished precision reference surfaces.
Inspection after machining also includes special verification for special-shaped structures. Inside the constant-temperature metrology room, coordinate measuring machines and laser interferometers with traceable calibration are used to inspect groove straightness, hole position accuracy and special-shaped contour dimensions. Each component comes with complete inspection records. Whether for custom single-piece special-shaped granite bases or batch multi-hole and multi-groove air bearing bases, dimensional tolerances can be stably controlled to meet assembly requirements of semiconductor, laser processing and precision metrology equipment.
In short, mechanically processed granite plates can be integrally manufactured with slots, holes, steps and special-shaped contours without splicing. With CNC mechanical cutting technology, dedicated diamond machining solutions and pre-processing stress relief, UNPARALLELED® overcomes the brittleness-related machining difficulties of granite. It integrally forms various special-shaped granite components and eliminates precision risks caused by splicing, providing monolithic granite benchmark solutions for high-end ultra-precision equipment.