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The Synthetic Granite

The company’s story ____________________________________________________________________________ Download Celith Dossier

The two Microplan Group fabrication units, Microplan France (previously Ateliers Maître Europe) at LA FORÊT DU TEMPLE (23) and Microplan Italia at VARALLO (Italy) are specialised in granite products for industry. Amongst the uses of granites are reference units for metrology, ultra stable bases for optics, machine tools bases. They are currently the best solution for micro-positioning machines taking into account cost accuracy and stability.

In order to meet customer’s new requirements for bases requiring less accuracy and reduced costs, but with high vibration damping characteristics, the Microplan Group has decided to develop a new composite granite-epoxy material called "CELITH". The CELITH company was founded in March 1999 in a 600 m² building on the same site as Microplan France, which enables CELITH to benefit from all their machining equipment and to obtain assistance with production and marketing. The growth of activity has led CELITH to double its building surface in 2005 (to 1 200 m²) in order to increase its manufacturing and storage capacity. At the same time, CELITH has invested in automated process equipment (a granulation station) in order to reach a production capacity of 20 tons/day.

The Microplan Group’s strategy of diversification has led CELITH into the field of technical ceramics in 2000. The principal activity is the manufacture of bases combining excellent rigidity, very high stability and low mass for mobile assemblies using air-bearing technology. This activity “CELITH – ASSEMBLY SYSTEM” has a building of 336 m² including a clean room of 40 m².
The product __________________________________________________________________________________________________________________

“Celith” is a mixture of specific granite aggregates of various size graduations bonded with an epoxy resin and hardener.
These aggregates are from two sources :
- Diorite (fine) and
- Blue granite from Guéret (coarse).

This composite granite is suitable for moulding which means significant cost reductions. This technique simplifies the manufacturing process by eliminating certain stages of manufacture (cutting, milling and drilling). It is also possible to add elements by bonding or remoulding. “CELITH” is produced and shaped at ambient temperature in a mould. It is possible to incorporate threaded inserts, hydraulic or pneumatic tubes, “Tee slots”, metal reinforcing and granite components to rigidify the structure. Compacted by vibration it stabilises in a few days. “CELITH” can also be used to fill thin wall metallic containers by inserting hollow tubes to obtain a good mass/stiffness compromise.
Moulds made of melamine faced agglomerate wood are used for prototypes or small series. For big series, steel moulds are used, made from laser cut and welded sheet metal.
This composite, with its superior mechanical performances, meets the requirements necessary for machine tools structures. Its high damping properties produce in most applications (especially machine tools) increased performance rates whilst assuring the quality of machining (reduction of resonance phenomena, better cutting conditions and improved tool life and surface finish).
The low conductivity of the composite gives it thermally isolating characteristics. Thus machine tools structures in "CELITH" obviate the need to stabilise by running the machine empty, previously necessary for traditional machines after a prolonged halt. This also means that production cycle breaks during the day have no impact on the machining accuracy. ”CELITH” is unaffected by oil, humidity or most chemical products.

Properties ____________________________________________________________________________________________________________________

Technical Properties
Unit
Celith
Density
Kg/dm3
2.3 à 2.5
Compressive Strength
N/mm²
120 à 150
Tensile Strength
N/mm²
10 à 15
Modulus of elasticity
KN/mm²
30 à 40
Coeff. of linear thermal expantion
10-6/°C
9 à 13
Thermal conductivity
W/m.°C
1 à 3

 

Equipments __________________________________________________________________________________________________________________

CELITH has a 1 200 m² building and 70 m² offices.

Production equipments are :

- Granulation station 20 t/day
- 2 vibrating tables 2 500 x 4 500 mm
- 1 vibrating table 1 250 x 2 500 mm
- Overhead 10 t gantry cranes
- Fork lifts 1.5 to 5 t.
- High-pressure cleaners
- Automatic soldering station
- 40 m3 steam room
- Vertical wood panel saw and wood working equipment
- Lathe – milling machine – drilling machine – cutting machine
- Painting installation
- Materials qualification laboratory
- Various manual tools

Fabrication of the " CELITH " _____________________________________________________________________________________________________

PREPARATION OF MOULD : To facilitate the removal of components from moulds, a layer of wax is applied and a demoulding agent is sprayed over the entire mould.

PREPARATION OF THE CELITH : Aggregates, resin and hardener are proportioned automatically from the control desk of the granulation station. They are mixed together then poured into a hopper.

CASTING OF CELITH : After each pouring « CELITH » is spread manually over the whole mould to obtain a better distribution of the product. Vibration tables ensure correct distribution of the resin around the aggregate, evacuation of air trapped during pouring and erosion of the contact points between stone chips.

REMOVAL FROM MOULD : A high-pressure cleaner removes the demoulding agent. Once finishing touches achieved the part is ready for machining and control which are subcontracted to Microplan France. The part may be painted.

Our main customers produce machine tools using composite granite as support (SOMAB, MORETTI, BALANCE SYSTEM, ETAMIC, FAVRETTO, VI TECHNOLOGY, …).

Assembly System

Our know-how in materials and air-bearings has enabled us to develop micro-positioning systems using granite as the static element and technical ceramics as the mobile elements. The stability of these materials and the absence of physical contact during the guide way displacement guarantee us repeatable precision better than a thousandth of 1 mm.

 


 

Equipments ____________________________________________________________________________________________________________________

CELITH has a building of 336 m² including a clean room of 40 m².

Production equipments are :
- Lathe and milling machine
- Granite surface plates and measuring columns
- Microptic autocollimator
- Electronical levels
- ...…

Our main Customers build measuring machines as MICRO-CONTROLE, SOPRA, KODAK POLYCHROME, SNECMA, ESRF...

Contacts _______________________________________________________________________________________________________________________

Contact : Philippe DUGENEST, Plant Manager

2, La Graule - 23360 LA FORET DU TEMPLE
Tél. 33.5.55.80.54.54 - Fax 33.5.55.80.54.50
Email : celith@microplan-group.com