2012 Presentations

A lot of new molding compounds have become available in the past few years. Are they better? How does one choose the best compound for the molding job at hand? This presentation is a survey and comparison of different mold cutting styles in various mold materials including rubber, silicone and room-temperature vulcanizing (RTV). In this study, a disk-shaped pendant, a stone-set ring and a simple wide-band ring models are molded in these various materials. Cutting styles are compared to reveal the best technique and material for each type of model. Several traditional venting techniques are used to vent air from the mold cavity. A demonstration of a novel RTV molding technique for small shops and modeling departments is included.

Selective laser melting (SLM) of layered gold powder is a rapid manufacturing (RM) technology capable of turning a CAD model into a piece of jewelry without intermediate steps. As with any new technology, giving concrete and tangible form to concepts requires research and development and, as Strauss (Santa Fe Symposium, 2009) pointed out, issues can arise with RM jewelry regarding powder quality and availability. This paper focuses on these issues together with laser power, laser scanning speed and the thickness of powder layer. A design of experiments (DOE) approach was used to characterize the influence of these variables on an 18K gold powder with reference to physical and chemical attributes, surface roughness, defects and mechanical properties. A comparison of a series of specimens produced by SLM and lost wax casting will be presented.

This presentation is an attempt to evaluate how research and development may influence the jewelry industry in the near future. It will present a survey of some ongoing research and development projects and will examine an exercise to visualize future R&D in the jewelry field.
Different technological processes giving rise to new gold alloy effects, gold colors, powder metallurgy and gold-based composites and new gold coatings will be presented. Other technologies such as 3D textile-based techniques, sputtering, sintering and nano-technologies will also be assessed. Finally, future trends in R&D to produce transparent gold, color-changing gold or functional/smart gold alloys will be discussed. This presentation is intended to spark new ideas about the nature of jewelry in the future and show how research and development may influence trends in jewelry design.

Foldforming is a new system using sheet metal to create surfaces and three-dimensional forms quickly. Foldforming uses hand working methods and the metal's plasticity and ductility to rapidly make complex forms resembling chased, constructed and soldered shapes from single sheets of metal without soldering. Thin materials may be used, creating light volumetric objects and surfaces. Radical changes in cross section are possible in three to five minutes. The tools are simple: fingers, hammers, mallets, anvil, vise and rolling mill. It has been recognized as a completely new approach to metal working by the Rolex Awards for Enterprise Committee and the head of the British Museum Laboratory. The presentation outlines the system and gives examples of technical procedures. Hints of how industry can utilize this approach are addressed. The shapes and forms model natural shapes and have relationships with natural laws of form generation, which has implications for other areas of science and insight into materials.

A recent development in metallurgy and materials science has created tremendous opportunities for new jewelry manufacturing methods and innovations in precious metal alloy recipes. The arrangement of atoms and crystal formation are considered the building blocks of metal alloys and solidification. Porosity, shrinkage, mechanical properties and corrosion resistance are just a few examples of metal alloy characteristics that can be improved by careful control of microstructures.

Thermodynamic modeling combined with carefully controlled solidification study has made it possible to tailor the size and type of crystalline structures formed in bulk precious metal alloy specimens. Crystallographic, microstructural, thermodynamic, mechanical and thermal studies have allowed for fine-tuning the alloy compositions and structures to tailor them to particular applications. In one particular gold alloy system, crystals from a few nanometers up to sub-micron sizes were synthesized to improve its mechanical properties, corrosion resistance and processability. Many interesting physical properties were observed in these alloys; for example, hard nanocrystals can now be introduced on the gold alloy surface, resulting in hardness values approaching 450HV.

A series of silver alloy systems was designed with extremely low melting points so that the molten silver alloy liquid could be cast directly into high-temperature rubber or silicone molds. The processing step is similar to that of wax injection with molten liquid silver injected in place of wax. Silver jewelry articles with good finish can be readily obtained from the silicone molds.

A journey of research in action: the commission—a palladium claret jug. Created by the British master craftsman Martyn Pugh, it is reputedly the largest decorative use of palladium to date. This jug continues Pugh’s challenging tradition of seamlessly dovetailing design, alloys, production and master skill to produce what appears to be an effortlessly elegant object. This deceptive elegance belies the enormous learning curve of tenacity, creativity and innovation that brought this object to life. The brief required a matching palladium jug to accompany the existing ‘pure’ gold sister jug (Santa Fe Symposium, 2010). Although the shape of the jug was the same, there were questions regarding which palladium alloys should be used for various components, who had the experience, and if existing knowledge of working palladium would be applicable or if there were limitations in working with palladium on this scale (360mm high). Pugh’s manufacturing decisions were informed by researching all possible options to determine the least risky approach. The metallurgical demands of pure palladium and its alloys required a different manufacturing approach from those used for the gold jug, and new lessons were learned. The jug was completed in the autumn of 2011 and had its debut at Goldsmiths’ Fair London before being placed with its sister in the client’s private collection.

In Part I last year, the effect of alloying on the various properties of the jewelry precious metals and their alloys was examined and related to microstructure through an understanding of phase diagrams—the metallurgist’s ‘road maps’ of alloying behavior. The influence of working and annealing on properties was also explained. We noted that properties, alloy composition and microstructure are all interrelated.

In this second part, we focus more on the alloy macro- and microstructures and how they are affected by its processing history—solidification conditions, working and thermal treatments—which, in turn, influences the final properties. We look at metal integrity, microstructure development and defect formation during casting and working and how microstructure is important to both manufacturing and service performance.

The increased use of 3D CAD and rapid prototype machines to create unique, custom-designed jewelry challenges jewelry manufacturers to cast new products free of defects and with minimal expense. In last year's paper ("Combining Art and Science to Optimize the Investment Casting Process"), a model of the casting process was used to simulate mold filling, temperature, velocity, liquid height and solidification rate. The objective of the current study is to validate the model with experiments and create a program that can be used as a Rhinoceros® plug-in or stand-alone. The aim of the program is to take data from the 3D CAD model to predict the outcome of the casting process under specified casting conditions or to recommend optimal casting conditions.

The importance of a material's microstructure is well known. When problems arise working with precious metals and alloys, the causes of failure can be understood and possible solutions found by examining the material's microstructure. The traditional stereo optical microscope is very useful for a good three-dimensional view of a sample, but the magnification is limited. Furthermore, the most popular techniques to observe microstructures, such as optical metallography and scanning electron microscopy, usually give a two-dimensional view of the sample. New 3D techniques are now available but they are not yet widely used, especially in the precious metals field. The aim of this work is to review many different microstructures in 3D, from fracture surfaces to as-cast surfaces or material defects, and show the information that the stereoscopic view can offer. This will be done through anaglyph images obtained by the scanning electron microscope and by providing the audience with the proper glasses for 3D vision.

Ultrasonic sound energy is widely used for cleaning in the jewelry industry at various stages of the manufacturing process. Factors that influence cleaning time include ultrasonic wave energy, frequency, the chemistry and concentration of the cleaning solution, thermal energy, and the type of contaminant (schmutz) on the jewelry surface. This paper will report on new research showing how a dramatic decrease in cleaning time and superior localized cleaning effectiveness can be achieved without increasing the ultrasonic sound energy that could damage more delicate jewelry. Even more interesting, the cleaning acceleration persisted only as long as solid contaminants were present on the jewelry surface. This paper will explore the various factors of ultrasonic cleaning performance, give helpful insight into testing your ultrasonic machine, provide illumination on the black art of ultrasonic cleaner optimization, and reveal the secrets to decreasing your ultrasonic cleaning times by up to 60 percent.

Business leaders today face increasing pressure to generate new growth and revenues while simultaneously reducing cost. They must continuously find ways to "do more with less." The unprecedented inter-connectedness of the global economy mandates new ways of working to survive. One approach to meet these challenges: radically simplify existing processes. Radical simplification represents a 50 percent or higher reduction in either elapsed cycle time, costs per transaction or process handoffs.

Many disciplines exist to address process simplification. This paper presents an overview of Lean Six Sigma. It introduces how the merger of Lean and Six Sigma yields the best of both worlds. Lean focuses on the elimination of non-value-added process steps to improve operational and financial performance. Six Sigma is the elimination of defects and variability of performance within a process. Combining the two provides a powerful, scientific approach to solve business problems.

A lean manufacturing environment, a skilled workforce, successful product introductions, efficient implementation of new technology, and relentless process improvement are all necessary to keep up with the demands of jewelry manufacturing in the twenty-first century. Building a resilient workforce that can grow and collaborate across your organization is key to meeting these challenges.

This paper demonstrates how to implement basic communication tools and meaningful metrics that will build a successful manufacturing operation. It will detail the tangible steps you can take to reduce cycle times, respond effectively to change, develop a skilled and engaged workforce, achieve better quality, and consistently collaborate to meet your business challenges today and into the future.

In jewelry manufacture, it is recognized that alloys and other materials should meet the needs of the manufacturing processes and that the resulting jewelry should give good service performance when worn by the customer. To ensure these needs are met, it is necessary to know certain properties such as density, tensile strength, hardness, color, tarnish resistance and precious metal content. It is a balance to ensure that the jewelry meets the needs of being “fit-for-purpose” while keeping costs to a minimum, for example, by reducing the weight of metal in the piece.

Sometimes we measure the properties ourselves but often we rely on data from external sources such as alloy suppliers and the scientific literature. How much reliance can we place on the values we obtain in property testing? Are we measuring the property correctly? Are we measuring the right properties? What can property measurements tell us in terms of their applicability to the manufacturing situation? This paper considers the measurement of the properties of jewelry alloys and of actual finished jewelry. It reviews the important properties, how they are measured and what they tell us in terms of their relevance to jewelry manufacture and service performance. Mechanical, physical and chemical properties are considered. The importance of making measurements in accord with international standards and the need for industry-agreed standards for testing of actual jewelry are emphasized.

Ceramic nano-composite cataphoretic coating (e-coating) is an innovative product ideal for the protection of metal surfaces. Thanks to the presence of ceramic nano-particles in its formula, its wear resistance is improved as well as its sensation to the touch compared to the traditional e-coatings available on the market today. Moreover, as it can be colored by the addition of pigments, it offers the possibility of combining both protective and decorative purposes on jewelry components. This paper is focused on presenting both transparent and several colored e-coatings with experimental results confirming their exceptional resistance to wear and tarnish in comparison to traditional coatings obtained by chemical passivation, electroplating and PVD technique.

The fact that this Symposium has published eight papers on the subject of tarnish in recent years is an indication that this is an important topic to our industry. A survey of the existing literature clearly points to a lack of uniformity in test methods for tarnish. Is there a better approach to tarnish testing and can the jewelry industry look to other industries for answers? This paper will review standards and techniques used in the electronics and telecommunications industries for accelerated corrosion testing and how these methods can be better predictors of how metals used in jewelry will tarnish and age in actual use and storage conditions. Through more enhanced testing using the actual gases that cause corrosion at levels that can be used to predict future behavior, we can have a better understanding of what our creations will face in the real world, and we will be in a better position to determine how best to protect the pieces from the ravages of tarnish and corrosion.