Granite in metrology
Granite, thanks to its properties, has in recent years found extremely wide use both in the field of traditional measuring instruments, surface plates, straightedges, squares, and for the production of high-precision bases and components for coordinate measuring machines (CMMs) and machine tools, machines for microelectronics and semiconductor production and, more generally, for all machinery where a high level of dimensional and geometric stability is absolutely necessary.
When it comes to materials for high-precision industrial applications, granite today represents one of the best solutions on the market, and thanks to the range of granites used, the Microplan® Group is able to provide products more targeted to each type of application.
The reasons that led to the choice of black granite for the production of extremely high-precision parts
Granite is the perfect material for the production of metrological measuring instruments, such as surface plates, straightedges, squares, cubes and parallelepipeds, and small-, medium- and large-size bases. Its choice is determined by the exceptional technical characteristics that distinguish it, making it irreplaceable in applications where the following are required:
Dimensional stability
Granite is a material that has naturally aged for millions of years and is therefore very stable and virtually free from internal stresses.
Thermal stability
The linear expansion coefficient of granite is decidedly low and significantly lower than that of materials typically used for precision mechanical applications, such as steel and cast iron.
Hardness and wear resistance
The hardness of granite is comparable to that of good hardened steel.
Wear resistance
Its hardness ensures a longer useful life for instruments and bases
Machining accuracy
Granite makes it possible to obtain surfaces with very tight geometries and flatness.
Electrical insulation
Granite is considered a good electrical insulator.
Resistance to acid attack
Granite is a material that resists most acids and chemical substances without deterioration, even the most aggressive ones.
Oxidation resistance
Granite is not subject to oxidation and therefore does not require surface treatments or painting.
Non-magnetism
Granite is generally an almost completely non-magnetic material. In particular, Nero Africa granite is recommended for all applications where this requirement is essential.
Reconditioning
Our granite instruments can be periodically reconditioned in a short time, restoring their original precision and extending their useful life to avoid the issue of “end of life”.
Cost
Thanks to new technological processes, products made of granite are generally advantageous both technologically and economically compared to metal products, particularly when considering the enormous advantages resulting from reduced assembly and setup times for the mechanical components that must then be mounted to produce the finished product.
Sustainability
Granite is a natural material already ready for use, available in nature without the need for complex or highly energy-intensive production processes. For this reason, its energy impact is much lower than that of materials such as steel, cast iron and ceramic. A further strength is its extraordinary durability: granite can be reworked numerous times while maintaining high performance. This makes it an excellent solution not only from a technical point of view, but also in terms of environmental sustainability, waste reduction and optimization of the product life cycle.
Download the data sheets with the technical characteristics of materials for metrological use:
Superior properties of absolute fine black granite
Our GNU | CR5 absolute fine black granite, thanks to its technical characteristics, is the most suitable material for applications requiring extremely high-level performance that cannot be achieved with other types of granite.
GNU Absolute Black granite stands out in particular for its high modulus of elasticity and very low porosity. These characteristics make it the ideal choice for the production of instruments, components and bases where very tight geometric tolerances are required, therefore requiring an extremely stable material that is resistant to deformation, and for applications where the required final roughness is very low, such as sliding on an air or oil cushion, pneumostatic, vacuum-pneumostatic and hydrostatic systems.
It is also particularly suitable for instruments, components and bases that must be used in cleanrooms, thanks to the low porosity and roughness obtainable after the lapping process.
Why choose black granite?
Black granite is the perfect material for the production of small- and medium-size bases and metrological measuring instruments, such as surface plates, straightedges, squares, cubes and parallelepipeds. Its choice is determined by the exceptional technical characteristics that distinguish it, making it irreplaceable in applications where the following are required:
Flatness: Perfectly flat surfaces for high-precision measurements.
Dimensional Stability: Resistance to environmental variations, ensuring consistently reliable measurements.
Precision for pneumostatic sliding: Ideal for applications using air-cushion pads, ensuring uniform and friction-free sliding.
Thanks to these properties, black granite and fine black granite are widely used in metrology laboratories, mechanical industries and for applications where measurement quality is fundamental.
Better mechanical properties
Dimensional stability
Excellent geometric stability
Low porosity
Low porosity and surface roughness achievable through lapping
Uniform and compact aesthetic appearance
Microplan Group: experience and quality in selecting the best granites
In the field of precision engineering and metrology, the choice of material for the production of precision bases and components is crucial. Each granite is distinguished by its physical-mechanical properties, but only some are ideal for applications requiring high stability, precision and durability over time.
Thanks to 50 years of experience and in-depth knowledge of materials, Microplan Group has developed a network of selected suppliers and partners to guarantee constant supplies of high-quality raw material and respond efficiently to the different requirements of Customers.
For each project, Microplan Group analyzes the Customer’s requirements and suggests the most suitable type of granite based on:
Required tolerances:
materials selected to ensure accuracy and precision over time.
Type of use:
heavy-duty applications in terms of wear require the use of harder and more resistant materials.
Product dimensions:
the choice is particularly influenced by the dimensions of the product, since large-size products cannot be manufactured with all types of materials due to raw material availability.
Other requirements:
other specific Customer requirements determine the choice of granite, such as the need for vibration damping, final weight, surface roughness, etc…
Microplan Group uses granites from South Africa as well as from Europe: this not only guarantees high quality, but also reduces environmental impact thanks to lower emissions linked to block transport. This attention to sustainability translates into economic advantages for our Customers, without compromising machining quality.
Relying on Microplan Group means choosing experience, quality and a responsible, sustainable approach to the supply chain.
"Conflict-free" certified materials: ethics and sustainability
The Microplan Group uses only materials certified as compliant with “Conflict minerals” regulations, guaranteeing the ethical and sustainable origin of raw materials.
This commitment ensures that Microplan products comply with European and international directives, contributing to corporate social responsibility and transparency throughout the production supply chain.
Africa Black granite
Thanks to its properties and excellent price/performance ratio, Africa Black granite is widely used both for the production of measuring instruments and for structures and bases for numerous small-, medium- and large-size applications.
Absolute Fine Black
Thanks to its properties, Absolute Fine Black Granite is particularly used for the production of measuring instruments, as well as for structures and bases for small- and medium-size machines requiring extremely high performance in terms of accuracy and stability.
Microplan has selected a special Fine Black granite for its machinability and stability: GNU | GR5 absolute black granite
Lanhelin Blue granite
A granite originating from northern France, Blue de Lanhelin is used by the Microplan® Group for the production of large-size bases and measuring benches, over 4 metres: thanks to the proximity of the quarry to the French site of Microplan France, transport costs can be significantly reduced, optimizing supply times.
Tarn Granit
Originating from southern France, Tarn Granite is used by the Microplan® Group for the production of large-size bases and measuring benches: as with Lanhelin Blue granite, the proximity of the quarry to the French site of Microplan France makes it possible to reduce transport costs and optimize supply times.
Blocks of exceptional dimensions can be produced in this material.
Economic and practical advantages of granite
Choosing granite means making a strategic choice that combines technical and economic advantages. This material offers superior performance in terms of stability, precision and wear resistance, reducing maintenance costs and extending the service life of measuring instruments and bases.
For companies, choosing granite means ensuring constant quality and long-term savings.
Thanks to the modern technological processes adopted by the Microplan Group, the costs of bases, structures and components made of granite are competitive compared to those made of traditional metallic materials, while increasing their performance and durability.
Not only are the initial costs advantageous, but also those related to maintenance and subsequent reconditioning: maintenance operations on granite are in fact limited, simple and fast, minimizing machine downtime and ensuring a long-term return on investment.
A granite base or measuring instrument is truly “forever”, since restoration of flatness and geometries is always possible quickly and economically, even at the Customer’s site.
