North London based Alfred Terry & Sons has been making jewellery for around 100 years. Specialising in gem set products including wedding bands, pendants and earrings, most designs incorporate diamonds or semi-precious stones such as sapphires and rubies.
Previously family owned, Alfred Terry was the subject of a management buyout in 1997, and since then has won the Retail Jewellery manufacturer of the year award four times. The jewellery market is entirely fashion led, so the development of new ranges at a competitive cost is of vital importance to the success of the company, whose main channel to market is through around 3000 independent retailers.
A full range of rings
The concept for new jewellery is created by design consultants, and then finished and made production ready by Alfred Terry’s own design team. For engagement rings, the shank and the head which carries the diamond are made in two separate pieces. To produce a full range of rings in different finger sizes is relatively easy, requiring only two models to be made. Jeremy Banks, CAD/CAM Diamond Set Department for Alfred Terry, elaborated, “Wedding bands are very different, as they are made in one piece, with the design and gems spaced around the circumference of the ring, making it impossible to change the diameter. To achieve a full range of sizes would require a large number of models as each ring is unique. Manufacture by our previous methods would be both time consuming and uneconomic.” He continued, “To remain competitive with overseas manufacturers we had to take the cost out of the production process.”
Participating in a consultancy project with the Technology Innovation Centre at UCE Birmingham, led the company to look at hyperMILL®, hyperCAD®, and the Cybaman Replicator 6-axis Machining System. Previously, each size of wedding band would require an STL or wax model to produce a silver master by rapid prototyping, which could then be used to create moulds for lost wax casting of the finished ring. Now the wedding band is designed in hyperCAD, programmed in hyperMILL®, and machined directly into the gold or platinum using the Cybaman three dimensional machining system. Jeremy Banks said, “The new process has eliminated physical models. We can produce a complete range of sizes working from one CAD model by simply making a small change to the CNC data, milling the complete ring in one set-up.
Easy to use and reliable
Each of the holes cut to receive a diamond requires a precise groove cut around the inside circumference. The girdle, which is the widest part of the stone, can then be snapped into the groove. Finally, the gold is hammered and finished to provide a firm fixing for the stone. Jeremy Banks added, “We use bull nose cutters between 0.2mm and 1mm diameter to produce the fine detail. In addition to producing wedding bands, we can also use the software to design and programme silver models for earrings and pendants.” For two part rings manufactured by the previous process, it was difficult to ensure that the components fitted together without twisting. By using hyperMILL®, each part can be constrained by tiny machined fixing lugs, ensuring that the finished ring can be assembled perfectly every time. Jeremy Banks said, “hyperMILL® is doing a great job, it is always spot on. We get regular updates and the software is both easy to use and reliable. It only takes two minutes to generate the first programme in hyperMILL®, and a few seconds to alter it for the different ring sizes.”
By introducing hyperMILL® and the Cybaman 3D Machining System the company has been able to create a range of 100 new rings and reduce time to market. Jeremy Banks said, “If we had to make models this would have been impossible, requiring in the region of £150,000 worth of patterns. With the new equipment and methods, the costs are around £5,000. Minimising pre-production expenditure enables us to offer new products several times each year. Additionally, machining has given us sufficient capacity to double the size of the company and profitably create a sustainable product range.”