System for manufacturing a bevelled stone, particularly for a horological movement
A method and device for manufacturing a bevelled stone, particularly for a timepiece are disclosed. A precursor is produced from a mixture of at least one material in powder form with a binder. The method includes pressing the precursor so as to form a green body, using a top die and a bottom die comprising a protruding rib, sintering the green body so as to form a body of the future stone in at least one material, the body including a peripheral face and a bottom face provided with a groove, and machining the body including a substep of planning the peripheral face up to the groove, such that an inner wall of the groove forms at least a flared part of the peripheral face of the stone.
1 . A system for manufacturing a stone using a method for manufacturing a beveled stone for a timepiece, the method including
producing a precursor from a mixture of at least one material in powder form with a binder,
pressing the precursor to form a green body, using a top die and a bottom die, the bottom die comprising a protruding rib,
sintering said green body to form a body of a future stone in said at least one material, the body comprising a peripheral face and a bottom face provided with a groove, and
machining the body including planing the peripheral face up to the groove, such that an inner wall of the groove forms at least a flared part of the peripheral face of the stone, said system comprising:
a device configured to press the precursor, the device comprising the top and bottom dies arranged movable in a casing forming the green body of the future stone by pressing the top and bottom dies, the bottom die comprising the protruding rib and a punch, and the top die not comprising any protruding ribs, wherein
the protruding rib of the bottom die forms a closed curve in plan view and is configured to form a planar surface comprising the flared part of the peripheral face of the stone and to define an outer periphery of the stone, and
the punch is located within and separated from the closed shape curve of the protruding rib of the bottom die.
2 . The system according to claim 1 , wherein the closed curve of the protruding rib is substantially circular and/or centered on the bottom die.
3 . The system according to claim 2 , wherein the protruding rib has a substantially triangular cross-section.
4 . The system according to claim 1 , wherein
the punch comprises a main part having a conical shape and a cylindrical distal part with a point,
the punch is formed on a surface of the bottom die,
the punch extends from the surface of the bottom die in a direction by a distance less than a thickness of the green body in the direction;
the main part corresponds to a bottom part of a cavity of the future stone, and
the distal part corresponds to a top part of the cavity of the future stone.
5 . The system according to claim 1 , wherein
the protruding rib has a circular path at a top, and
a diameter of the circular path is a width of the future stone.
6 . The system according to claim 1 , wherein the protruding rib is configured to form the flared surface up to an apex in the body.
7 . The system according to claim 1 , wherein the bottom die comprises a single protruding rib formed around the punch.
8 . The system according to claim 1 , wherein
the bottom die comprises a single protruding rib formed around the punch,
the punch comprises a main part and a distal part formed on the main part which is provided with a point; and
a height of the rib is greater than a height of the main part.
9 . A system for manufacturing a stone using a method for manufacturing a beveled stone for a timepiece, the method including producing a precursor from a mixture of at least one material in powder form with a binder, pressing the precursor to form a green body, using a top die and a bottom die, the bottom die comprising a protruding rib, sintering said green body to form a body of a future stone in said at least one material, the body comprising a peripheral face and a bottom face provided with a groove, and machining the body including planing the peripheral face up to the groove, such that an inner wall of the groove forms at least a flared part of the peripheral face of the stone, said system comprising:
a device configured to press the precursor, the device comprising the top and bottom dies arranged movable in a casing forming the green body of the future stone by pressing the top and bottom dies, the bottom die comprising the protruding rib and a punch, and the top die not comprising any protruding ribs, wherein
the protruding rib is substantially circular,
the punch is located within and separated from the rib, and
the protruding rib is configured to form a planar surface comprising the flared part of the peripheral face of the stone.