Bulgari Bracelet Manufacturing at Prestige d'Or

Posting on behalf of Don Corson.





During a half an hour trip from Lengnau down in the valley to Saignelégier up in the Jura mountains we change the scene from the beginning of spring to winter.  From the first flowers up to a meter of snow still on the ground.  But it is melting fast.  Saignelégier has the honor of not only being the home of Prestige d’Or but, almost across the street, Switzerland's biggest horse market.  The week long festival of the main horse market each summer is one of Switzerland’s famous summer attractions.

Once here at Prestige d’Or we are back in the world of precision machining.  And as we know the work starts on a computer to determine the exact form of the pieces.


Again from this 3D description of the pieces command files for the CNC machines are generated.  And again, as at Finger for the casemaking, stamping and machining are often combined to create the final part.  Here we see an initial stamping and the final machined piece.


This is how the bracelet is formed for this distinctive ladies watch.


As we are used to in an industrial environment measuring equipment and technical drawings are found everywhere to control the dimensions of the pieces fabricated.





Here we see a CNC milling machine with its automatic material feed.  With this automatic feed the machine can operate for several hours, depending on the size and complexity of the pieces, until it needs human intervention to add new material.


Again measuring equipment, this time optical equipment with which, for example, an edge can be scanned to make sure that it has the correct form, or the distance between two hole centers can be accurately measured.





These smaller CNC machines are used to make the links in bracelets or the pins of a standard buckle.  Again the raw material is in the form of a 3 meter long bar which is placed in the long tray to the left.  Making such small parts the machine works for about 4 hours before needing new material.


These are the parts this machine has been making.


After the parts have been machined the finishing commences.  Here we see a buckle which has been selectively sand blasted in the center.


Many parts of bracelets are stamped.  Here we see some of the dies used for this stamping.


And here is a display of the different steps of stamping this center portion of a deployant buckle.  In general there is a heat treatment of the part between each stamping step so that the metal doesn’t become brittle.  The actual stamping is not done in house.  150 ton presses are not to be played with.



We now enter the finishing room, mostly empty as it is now lunch time.  But there are still a couple of people at work.


Here the first steps at cleaning up a buckle.





All the critical dimensions correct?


Polishing we saw already this morning at H. Finger.


Interesting is the hard soldering operation.  For this the pieces to be soldered together, the lugs on to a watch case, for example, are spot welded together to assure the positioning.  The solder paste is spread on the joint and the piece is sent through an oven on a conveyor belt.  The soldering room has 4 such ovens that are set to different temperatures from 800°C to 1000°C.  No extra heating is needed in this room!

The workbench for spot welding.


One of the ovens.


Finally the many pieces of a bracelet are assembled.  Here we can see all the pieces.





Two finished deployant buckles.


This finishes our visit to Prestige d’Or.
After lunch we will visit Bulgari's dial maker Cadrans Design in La Chaux-de-Fonds.



This message has been edited by Kong on 2009-06-02 12:57:25 This message has been edited by AnthonyTsai on 2009-06-02 20:43:24 This message has been edited by MTF on 2009-06-05 04:28:18