BACKGROUND

Silver has long been used for fabricating jewelry. Small quantities can be melted using a blow pipe, and traditionally, silver rings and pendants have been fabricated by investment casting, using the lost-wax technique, wherein a former is made from a soft material like wax, which is then cast in plaster or clay. The mold is heated to melt the wax which is removed and then molten silver is poured in.

Silver is ductile and malleable and may be cold worked, i.e. hammered and shaped on an anvil. This technique is popular for fabricating goblets and the like, and may even be mechanized using a lathe. Items may also be stamped out of silver using a die stamp. Coins have long been produced using a stamp of harder material, and the technique is appropriate for signet rings and the like.

Another established technique for fabricating jewelry from silver is filigree. Here silver is drawn into wires, and these are fabricated into brooches, pendants and also boxes and the like.

To some extent, silver is sawn and filed, but generally machining causes wastage and is discouraged for that reason. Finally, machining produces a mass-produced finish, which is totally at odds with quality jewelry.

The fabrication of jewelry from silver has hardly changed in the past couple of millennia. Nevertheless, the current techniques are labor intensive and silver jewelry is rather more expensive than the worth of the metal therein.

Other jewelry metals include gold and platinum.

SUMMARY OF THE INVENTION

In accordance with a first aspect of the invention, there is provided a piece of jewelry fabricated from precious metal feedstock using at least one technique selected from the list of milling, grinding, drilling and slotting via CNC (Computer Numerical Control) on a computer controlled machine using at least one machine tool.

Typically, the piece of jewelry is fabricated on a computer controlled machine using a plurality of tools.

A second aspect of the invention is directed to a method of fabricating a piece of jewelry from jewelry metal feedstock comprising programming a CNC machine and machining the piece of jewelry from the jewelry metal feedstock. Typically, the step of machining comprises at least one process selected from the group consisting of milling, grinding, drilling and slotting.

More typically, the step of machining comprises a plurality of sub-steps including at least two separate machining processes.

Optionally, the step of machining comprises using a plurality of tools.

Optionally, the silver feedstock is selected from the list of rods, tubes, ingots and sheets.

Typically, the jewelry metal is selected from the list of gold, silver, platinum and alloys thereof comprising at least 50% of gold, silver or platinum.

Most typically, the jewelry metal is selected from sterling silver or 9 Karat gold.

Optionally, the piece of jewelry is selected from the list of finger rings, nose rings, necklets, bracelets, pendants, ear-rings, navel rings, piercing studs, cuff links and brooches.

Optionally, the piece of jewelry is fabricated on a single work station.

Typically, the feedstock is dry machined.

Typically, the piece of jewelry is designed using a CAD program.

Generally, the CAD program produces a design as a data file and the CNC machine uses the data file to machine the jewelry piece.

Optionally, fabrication further comprises at least one of the group comprising laser cutting, welding, friction stir welding, ultrasonic welding, flame cutting, plasma cutting, bending, spinning, picking and placing (PnP), and sawing.

Optionally, fabrication further comprises machining a gem mount for mounting a gemstone therein.

The gemstone is selected from the list of precious stones, semi-precious stones and artificial gem stones. DEFINITIONS

Silver, as used herein refers to the element Ag, a whitish metal. More generally, and unless there is indication to the contrary, silver refers to alloys containing at least 800 parts per 1000 of silver.

Sterling silver relates to silver alloy containing 925 parts per thousand of silver.

Gold may be any gold alloy including 9 Karat, 14 Karat and 22 Karat gold.

Feedstock is a raw material that may be sheet, rod, bar, ingot, tube or the like, from which objects may be fabricated.

Machining implies any mechanized working of a work-piece to shape same, but particularly milling, drilling, turning and slotting. Dry machining means machining without lubricants and cooling fluids.

CNC is an acronym for Computer Numerical Control and relates to a machine that can be programmed to perform a number of machining functions to produce a finished article from a workpiece, typically feedstock.

CAD is an acronym for Computer Aided Design

CAM is an acronym for Computer Aided Manufacture

DESCRIPTION OF FIGURES

For a better understanding of the invention and to show how it may be carried into effect, reference will now be made, purely by way of example, to the accompanying drawings.

With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only, and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention; the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice. In the accompanying drawings:

Fig. 1 is a flow chart illustrating the main steps for fabricating jewelry in accordance with a generalized embodiment of the present invention, and

Fig. 2 is a schematic representation of a machine tool coupled to a CNC computer and holding a piece of raw feedstock jewelry metal, specifically a length of silver tube. DESCRIPTION OF THE EMBODIMENTS

Machine tools such as milling machines, lathes and the like have been automated, enabling their operation by abstractly programmed commands encoded on a storage medium, as opposed to manually controlled via handwheels or levers, or mechanically automated via cams alone. In CNC (Computer Numerical Control) systems, end-to-end component design is highly automated using CAD (Computer Aided Design) or CAM (Computer Aided Manufacture) programs. These programs produce a computer file corresponding to a design that is interpreted to extract the commands needed to operate a particular machine, and then loaded into the CNC machines for production. Since any particular component might require the use of a number of different tools— drills, saws, etc.— modern machines often combine multiple tools into a single "cell". In other cases, a number of different machines are used with an external controller and human or robotic operators that move the component from machine to machine. In either case, the complex series of steps needed to produce any part is highly automated and produces a part that closely matches the original CAD design.

CNC is widely used for mass production and for making components to high tolerances.

Whilst many materials can be machined, machine tools are typically used on hard materials such as steels.

CNC has been used to make such formers for investment casting, but has not used directly for processing silver to make jewelry. Although silver machines well, hitherto, machining of silver has generally been limited to engraving trophies and the like.

Bearing in mind that silver is rarely machined at all, apart from stamping and very occasional drilling, it has surprisingly been found that silver may be machined dry. In experimental tests, silver finger rings, pendants and decorative objects such as ear rings and studs have been machined from silver rods, pipes and sheet silver cut using CNC and a wide range of finishes and surface decorations have been imparted to such silver jewelry, using milling and similar machining techniques. It has been surprisingly found that quality silver jewelry can be mass produced using techniques previously used in jewelry fabrication for stainless steel and titanium jewelry, including watch bracelets and backs of watches, for example, to the best knowledge of the applicants, with considerable literature searching, CNC has never hitherto been used for fabricating jewelry from silver. Using CNC for making jewelry and for processing silver is simply counter-intuitive. CNC is also not used for machining gold and platinum.

However, it will be appreciated that CNC may be used for sizing a ring from a rod or pipe, for shaping and for applying surface finishes, including engraving.

With reference to Figs. 1 and 2, a method of fabricating a piece of jewelry from a jewelry metal such as silver is shown. The method includes the following steps:

(a) programming the computer 12 of a CNC machine 10;

(b) introducing feedstock 16 such as rods, tubes, ingots or sheets of sterling silver, into the machine tool part 14 of the CNC machine 10. As shown herein, the feedstock 16 is a tube, and

(c) machining the piece of jewelry 18 from the feedstock 16.

The step of machining, typically includes at least one process selected from the group consisting of (cl) milling, (c2) grinding, (c3) drilling and (c4) slotting. Typically, the machining includes a plurality of distinct processes and typically uses a plurality of tools. Although different processing sub-steps may use different tools on the work- piece, it is generally held in the same chuck during the various sub-steps, several of which, if not all, are performed on a common workstation or cell.

Various pieces of jewelry may be fabricated in this manner, as stainless steel jewelry has been fabricated in the prior art. Inter alia, such jewelry includes finger rings, nose rings, necklets, bracelets, pendants, ear-rings, navel rings, piercing studs, cuff-links and brooches.

An advantage of using CNC is that the jewelry can be designed using a CAD program which produces a design as a data file which is then used to program the CNC machine which uses the data file as a pattern or recipe to machine the jewelry piece.

In some embodiments, gemstone mounts are machined into the piece of jewelry and then gemstones are mounted thereon.

Although the step (c) of machining typically includes one or more processes such as milling, grinding, drilling and slotting, It may also include other processes such as laser cutting, welding, friction stir welding, ultrasonic welding, flame cutting, plasma cutting, bending, spinning, picking and placing (PnP), and sawing, for example. Typically, a device will be provided to enable collection of waste material, such as filings and turnings, generally shavings. The device may be a simple polyethylene sheet, for example.

In addition to silver, other jewelry metals of precious or semiprecious metals may be machined on a CNC system, particularly 9 Karat gold, for example. It will be appreciated that a CNC system may be used to fabricate a variety of jewelry pieces using a variety of machining techniques, and to decorate the jewelry in a variety of ways. The scope of the present invention is defined by the appended claims and includes both combinations and sub combinations of the various features described hereinabove as well as variations and modifications thereof, which would occur to persons skilled in the art upon reading the foregoing description.

In the claims, the word "comprise", and variations thereof such as "comprises", "comprising" and the like indicate that the components listed are included, but not generally to the exclusion of other components.