Cooksongold is a jewelry manufacturer that has been around for more than a century and is referred to as a “one-stop shop for anything jewelry”. Therefore, it should come as no surprise that it is one of the biggest jewelry manufacturers—and one of the most advanced companies in direct precious metal 3D printing—in the UK and one of the leading companies globally.
From drop stamp machines that are old enough to be in a museum to additive manufacturing (AM) that is almost futuristic, Cooksongold is running a big, and broad, operation.
The business model consists of three arms. The first is a one-stop shop for anything related to the manufacture of jewelry, everything from wire to rolling mills. The second part of the business is in the recycling and refining of precious metal scrap. The third part of the business is special products; precious metal components for dental and industrial applications. AM—an additional product offered to their 70,000+ customers—is used in conjunction with their traditional manufacturing techniques, and it’s considered a developing growth area for the business.
Traditionally, the company has focused exclusively on jewelry but now, with the aid of precious metal AM, has expanded into associated industrial applications, technologies and applications.
The impossible dream
Dr. Selassie, Technical Director and Head of AM at Cooksongold, describes the development of their AM manufacturing technology as “a labor of love” and, with reference to direct precious metal printing, elaborates, “we were the first ones that really got into AM.” This came with its challenges, such as educating the customers about the technology’s design.
“Unfortunately, with AM, everybody thought that you could make anything, which isn’t the case. Every technology has its design considerations and its limitations as well. There are some fabulous things that can be done but the customers have to specifically design for it, otherwise, it’s too expensive. If you can make it conventionally you should not touch this technology. It’s all about designing things that you can’t make another way. Whether its high relief parts, hollow or whether its fully articulating parts.”
The price of direct precious metal printing is expected to come down as it becomes more widely used and as economies of scale emerge but, in the meantime, when making something as simple as a plain wedding ring, for example, existing technologies should be used where possible. According to Dr. Selassie, “it was initially a struggle getting this across to customers. The customers that are successful in AM are the ones who design for the technology.”
With reference to a particularly intricate design—a fully articulating, 18-carat white gold and 18-carat yellow gold bracelet—that would take a traditional jeweler “weeks and weeks and weeks to make”, is printed within a matter of 10 hours using AM. “That’s where, really, AM comes into its own. AM was never intended to replace traditional manufacturing. It was always intended to be something that was added to the suite of available technologies.”
When Cooksongold started with AM in around 2010, primarily for manufacturing within the jewelry industry, they were working with EOS on one of the old systems, the M 280, but it was not designed for precious metal AM. So, partnering with EOS, it took approximately four years to develop systems and parameters more suited to precious metal AM, by reducing power trap points and adding filters that allow burning for recoveries. All of this allowed for significantly less powder to be lost in the printing process. The result was, initially, the EOS M 080 – now superseded by the EOS M 100.
With non-precious metal AM, when a small portion of the powder is lost in the manufacturing process it doesn’t really matter. But, when printing with precious metals, the powder that is put into the system is worth more than the system itself. For example, the powder to fill an approximately £200,000 machine (such as the EOS M 100) is easily worth more than £250,000, depending on the metal, of course. Losing a small portion of this powder would be a huge cost that would have to be charged to the customer.
Cooksongold is continuously developing new parameters for the alloys for their jewelry 3D printing systems, these parameters are made up of “hundreds of variables”, “everything from the width and speed of the laser to the amount of power that the laser is using, to the scanning strategy, to how close the laser paths are to each other.”
The high reflectivity and high thermal conductivity of metals such as copper and silver mean that “it is really difficult to get the energy into the parts”. This challenge was overcome through the development of the M 100’s 200-watt laser. Interestingly, platinum is the easiest metal to print with thanks to its low reflectivity and low thermal conductivity. “When printing with platinum, one can get really, really good quality parts and very fine-detail resolution,” Selassie said, “with densities of 99.99%.” Whereas, with traditional investment casting, one would really struggle to get platinum parts so dense. “Platinum is a key area of growth for AM technology.”
To offer an example of how the different metal powders compare when using AM, to print something that is approximately 10-15 mm tall, it would take about two to three hours using platinum, but eight to 10 hours using silver.
An industrial treasure
Recently, Cooksongold partnered with Renishaw and is, once again, working on the systems, powders and parameters to create larger components for more industrial AM applications, from printing platinum parts that are used to produce fiberglass with higher tensile strength for the reinforcement of doors and windows, to high-end applications, such as reinforcement for wind turbines that have to be strong but light. Other applications include parts that improve the thermal efficiency of copper cooling fins for the automotive and aerospace industry resulting in more efficient cars and planes.
Excluding their 20,000+ items and objects used for conventional jewelry making, Cooksongold sells its precious metal jewelry 3D printing systems, and/or the powder for the systems (which they make in-house), and/or prints the parts for the customer using their bureau service. It’s a full product offering.
The company is currently repositioning its bureau service, which will be relaunched later this year. Private customers and businesses will be able to completely customize the parts they need by uploading their designs to the website, articulating and scaling it, and choosing the different alloys—all with live pricing. Once the order is placed, Cooksongold aims to deliver the part to the customer within a week.
Currently, the AM department at Cooksongold consists of seven people (out of the approximately 260 company-wide), five EOS systems and one Renishaw system with a 250 x 250 mm platform. The team is also awaiting the delivery of a larger machine.
As you can see, Cooksongold is investing heavily into AM technology and will continue to do so. When asked about how much potential has been realized, Dr. Selassie reckons that AM, within the jewelry industry, is “maybe 10% of where it could go” and “only 5% industrially. We really believe in additive.”