19 December 2019

GRAUX participates in the realization of the project of all technological superlatives: the ELT!

The European giant telescope (ELT for Extremely Large Telescope) is the most ambitious project in the world and is supported by the European Southern Observatory (ESO). This telescope should allow major advances in the field of astronomy, in particular thanks to its primary mirror with a diameter of 39 meters.

When in June 2012 the ESO Board of Directors approved the construction budget for the giant telescope, the Dutch Minister in charge of Education, Culture and Science, Maria van der Hoeven declared “An almost unique level of international cooperation is achieved at ESO, and everything is done by those who can do it best, irrespective of their country or institution. This spirit of excellence is an example for all Europe. “.

GRAUX selected for its expertise in high vacuum technology.

GRAUX is part of this approach of excellence and has cutting-edge expertise in the manufacturing of industrial equipment using high vacuum technology. It is, among others, for these reasons that the manufacture of processing tools and stainless steel conveyors for transporting the mirror segments was entrusted to GRAUX.

The main mirror composed of 798 segments positioned with great precision.

The ELT telescope is composed of several mirrors of impressive formats which required extremely detailed studies and a level of production precision hitherto unattained.

Among these, the primary primary mirror M1 (f / 0.93) of the ELT has a diameter of 39 meters and, given its size, uses the segmented mirror technique, i.e. ‘it is made up of the assembly of several “small” mirrors. It includes 798 hexagonal elements 1.45 meters in diameter and 40 millimeters thick assembled like those of the Keck telescope in Hawaii. The mass of the primary mirror is 150 tonnes. The M1 mirror is supported by 30,000 supports which correct in real time the forces due to bending and deformation movements generated by the wind and the rotation of the mirror.

Schéma de l’ELT : M1 miroir primaire, M2 miroir secondaire, M3 miroir tertiaire, M4 miroir déformable (optique adaptative, M5 miroir renvoyant la lumière vers les plateformes instrumentales, 6 axe horizontal de la partie optique (hauteur), 7 plateforme instrumentale (x2), 8 lasers de l’optique adaptative (x6), 9 plateforme orientable (⇒azimut), 10 contreventements sismiques.

The regularly treatments of the mirror segments are carried out under high vacuum under extreme conditions.

These mirrors must receive a specific treatment renewed regularly. For this reason, and since the telescope is installed at an altitude of 3,000 meters in the Atacama Desert in northern Chile, ESO is building a mirror segment processing plant next to the giant telescope.

This specific treatment takes place under vacuum and requires specific tools to handle the mirrors in the vacuum chambers. And as happens in Chile, all the factory and all the tools must be able to manage the earthquakes without breaking glass …

Extreme conditions motivating the establishment of specifications demanding that GRAUX was able to win against a high level competition.

19 December 2019

A new SORALUCE FP 8000 milling machine is operational.

In October 2019, GRAUX started up a new milling machine with large dimensional capacity, more precise and autonomous. This equipment completes the upgrade of the entire production tool and thus meets the growing demand for the manufacture of large mechanically welded units.

Hosting a 26-ton machine in a working workshop presents many challenges.

The installation of this new machining set required careful preparation. The pursuit of activities in the hall intended to accommodate this machine should not be compromised while reorganizing the work areas in order to free up space for carrying out the important work necessary for the preparation of the slab. All this in a busy production planning period! The team was flexible and fully participated in the smooth arrival of this new ‘baby’.

The demolition of the concrete slab, the excavation and the clearing of 240 m3 of earth were completed at the end of May 2019. Then, during the month of June, specific reinforcement was carried out, the pouring of a concrete high resistance and the very precise production of the machine anchoring studs.

When August resumed, following the official summer closing, the milling machine was installed. After this work, which lasted six weeks, the first machine adjustments were able to start at the end of September. The final acceptance took place in early October.

Technical information of the milling machine.

Brand: Soraluce

Model: FP 8000

Longitudinal stroke (X axis): 8000mm

Vertical stroke (Y axis): 3100mm

Cross travel (Z axis): 1600mm

Milling head with automatic indexing, power 37 KW, rotation speed 7000 RPM

40 tools magazine

Heindenhain iTNC 640 digital control which receives programs from our CAD / CAM Mastercam.

Machine dimensions: 16250x8200x4130 mm

Weight: 26 T

Observed tolerances measurements upon receipt of the machine.

The machine was received in our workshops with the following measures:

  • Machine geometry accuracy according to ISO 10791-3:
    • X axis: 0.022 mm on the 8000mm
    • Y axis: 0.005 mm
    • Z axis: 0.02 mm
  • Head accuracy according to ISO 10791-3:
    • Spindle nose: 0.005mm
    • Spindle axis relative to the table: 0.004mm
    • Head rotation: 0.01mm

(source : Manufacturer’s video. The images at the end of the articles present the FP 8000 milling machine in our workshops.)

A new machine geared towards the needs of demanding customers.

This milling machine ideally complements all of our production tools. It allows us to respond, in particular, to specific needs both in terms of large machining dimensions and high production dynamics.

Here are its main advantages:

  • More capacity in terms of dimension;
  • Greater precision;
  • Machining in full autonomy (without permanent operator) thanks to the 40 tools cassette;
  • High spindle speed allowing better surface finish and faster machining of aluminum;
  • Perfect for machining large dimension welds.

Images of the milling machine in our workshops


31 December 2015

Electric consumption is an important issue for our company regarding cost management as well as enivonmental responsability.

A green solution has been developed with Issol company in order to install more than 340 photovoltaïc units on worshops’ roof. This production of 83 Mwh will assume a major part of our needs in electricity.

It is the first step before a production of 100% of our consumption in a green way.

Links to press articles:


Vers l’avenir


3 March 2015

Arrival of a new maching center from Mazak. With a table of 3000*800*700mm, moving head, this center is dedicated for a wide range of pieces with the highest quality and precision.

Video of the machining center in production:


15 November 2014

In order to meet the most demanding requirements, we are equipped with a LVD ECDP 5 320/4500 press brake.

This 320-ton press bends plates of carbon steel up to 12 mm thick and more than 4 metres long.

Its precision is remarkable and its speed is simply spectacular.

What this means for you
  • An eco-friendly machine that runs as economically as an electric press brake.
  • Robust and reliable hydraulics.
  • Course of the cylinders controlled by two ultra-price encoders.
  • CADMAN® Lite Adaptive digital control of the 5 axes.
  • Ideal for precision applications in competitive markets.
Installation report



23 September 2014

The maintenance of an industrial tool can often be expensive. In a context where budgets are tight, repairs offer a better solution to purchasing new equipment. But this is only true if you can trust the quality of the repair…

At Graux you find the expertise needed to analyse the state of your equipment and offer the optimum solution for your budget.

Thanks to a high level of know-how including boiler-making, welding and machining, Graux can recondition your piece – even very large items – and guarantee the quality of the result. So you make great savings!

Example of achievement

Reconditioning a rolling mill furnace door deformed by heat

The doors in rolling mill ovens suffer a lot. The temperature differences can be very significant and the handling conditions are difficult. But the door ensures the energy stays inside the oven. So it is a strategic piece of equipment for which we cannot take risks. Previously, the doors were replaced by new ones when they showed signs of fatigue.

Due to cost optimization, the maintenance manager was considering repairing the door – but there was zero room for error.

That is why he asked Graux to analyse the state of the structure and suggest a budget for reconditioning it, while guaranteeing flawless operation.

The budget offer was very interesting compared to the cost of a new door. Reassured by Graux’s know-how, the maintenance manager validated the repair. The intervention required a lot of analysis, caution and experience to dismantle, straighten and reassemble carbon steel and refractory stainless steel parts. Complex welding choices were controlled by our welding coordinator and we were able to propose an almost new part.

This first door was put to work during the following campaign and has now being working for a few years without worry. A second has just been rebuilt!


Photo report