Pushing the Design Envelope
It is widely accepted that the traditional ceramic industries in the U.S. are experiencing significant pressure from imported products and price competition. These factors, combined with economic uncertainties, have created an atmosphere that is receptive to new ideas and possibilities. "Customization," "niche building" and "product diversification" are all buzzwords for manufacturers in search of markets.
With this in mind, what if a new technology could offer multiple advantages and opportunities for change and flexibility? What if a manufacturer in the tile and trim industry could access a simple, inexpensive technology that would allow it to prototype new products quickly with a minimum investment in equipment? What if the much sought after "handmade" look could be replicated in volume without the loss of character that initially made it desirable, while maintaining quality and continuity, and eliminating the issues of drying, warping, shrinking and cracking associated with "handmade" products? Finally, what if the same technology were flexible enough to manufacture one piece or many, in single or multiple designs, simultaneously on the same line without prohibitive tooling costs?
A new manufacturing process promises to offer these advantages. Called the DanteceramicTM Process, the technique is providing new opportunities for manufacturers of a variety of ceramic products.
Humble BeginningsThe process was developed six years ago in Australia by Eric Cossich and Katrina Kenny after initial investigations revealed a need for large slabs of ceramic for the outdoor furniture and restaurant market. At the time, Cossich was in early retirement after years in the wholesale and import/export businesses, and Kenny was a sculptor and artist. Although they did not have formal training in ceramics, they began an intensive research and development project to create a ceramic body that could be used for tabletops.
Cossich and Kenny spent the first two years experimenting with various combinations of raw materials to make a strong body with an attractive appearance. The principals worked through countless variations of ingredients that, in hindsight, would seem at best unlikely and at worst ludicrous. However, after much time and effort, their hard work paid off. Once their formulation seemed to have possibilities, Cossich and Kenny sought the advice of the Commonwealth Scientific Industrial Research Organization (CSIRO), which was able to offer additional insights and help move the process forward. The result was a small but efficient manufacturing plant capable of producing versatile, high-quality products for the giftware, architectural and furniture markets at a low cost.
Process ComponentsThe secret behind the new process is a combination of proprietary raw materials and flexible tooling. The dry portion of the raw material mixture consists of a receptor, which is composed of readily available ceramic ingredients, and a filler. The filler can be a wide variety of solid ceramic particulate matter, such as waste porcelain, coal combustible byproducts (CCBs) or waste tile, sized from dust to 1⁄4 in. (5 mm) particles. The mixture can also be adapted for various applications-for instance, ground terra cotta, cordierite, colored tile or colored oxides can be used to create different colored bodies. A company using this process can essentially crush any "fired" ceramic waste into a sized grog and use it as the filler for the process.
A proprietary liquid setting agent is added to the dry mixture to create the final material formulation, and this agent can be manipulated to control the rheology and rate of development of body green strength. When combined in measured proportions with water (<9%), the mixture becomes a thixotropic (shear-thinning), formable mass that can be placed, extruded, cavity cast or (with some modification) dry pressed into a variety of molds.
The forming technique, which is pivotal to the success of the process, uses simple, readily available equipment and tools. Masters for molds can be made of a vast array of materials, including unfired clay, wood and wood composites, stone, plaster, textiles and organic materials. Plastic, resin or metal can also be used. The molds themselves can be made of any flexible, non-porous material, such as polyurethane or silicone. (Both of these materials offer longevity and versatility for many different forms.) The mold materials are simply poured over the master form to create the finished mold.
By using this relatively inexpensive mold method, small volumes can be efficiently and viably managed for sampling or prototyping without high costs or inconvenience. Furthermore, this low-cost mold system makes even one-of-a-kind or low-volume custom projects feasible. The durability of these materials also enables relatively high-volume production-often exceeding 1000 pieces per mold.
The proprietary material has also been successfully cast into vacuum-formed molds. Vacuum-formed tooling in various-weight plastics is a very cost effective way of producing small to large production volumes of certain items, especially within a tight time frame, and can either be made in-house (a vacuum forming machine typically ranges from $10,000-20,000) or outsourced to an outside contractor. Making the molds in-house can help ensure a rapid turnaround of small-volume or one-of-a-kind products, while outsourcing might be more cost-effective for companies with large production runs.
Once the products have been formed, they can be fired and glazed using conventional equipment and processes.
Unusual PropertiesA primary advantage of the new process is the high green strength of the ceramic body. The body "sets" in the mold and can be removed within an hour. It can be fired immediately after curing without conventional drying, resulting in time and energy savings.
In a batch or tunnel kiln, the unusual green strength of the ceramic body allows products to be densely stacked, or "bookcased," which allows for the maximum use of the available kiln area. The robust nature of the green product also reduces waste from product losses-small production facilities have achieved average losses below 5% when using this process. In addition, the body's high green strength allows the use of undercuts and complex detail in molds.
The ceramic body produced through this new process also exhibits another unusual property-extremely low shrinkage. The formulation shrinks only 1% from the green to fired stage, even when used as a castable, resulting in a stable and predictable body. This enables the reproduction of very complex and detailed objects-even those with differing volumes across a form. For instance, in the grape panel, the grape bunches are in solid forms up to 3 in. (75 mm) thick. Compare this to the background of the panel, which is as thin as 0.2 in. (5 mm). Pieces like this can be easily reproduced and fired without cracking, distortion or deformation.
The ability to precisely duplicate intricate shapes in a ceramic material is unique to the process. It can be used to reproduce the grain of wood or the weave of a textile, or to produce high-relief shapes with a "hand-sculpted" look. Specialty tile, architectural wall panels, moldings, and other architectural elements and wall décor can all be produced economically with this process. Additionally, a low coefficient of thermal expansion combined with the low shrinkage characteristic enables stainless steel mechanical fasteners (screws, bolts, wire, etc.) to be added during the forming process, rather than in an extra, time-consuming step before shipping, which provides an added benefit for manufacturers of architectural products.
The high green strength and minimal shrinkage of the material also facilitates the production of large to very large pieces (e.g., 36 x 36 in. [91 x 91 cm] slabs and ionic columns 8 in. in diameter x 80 in. long [20 x 203 cm]) using very basic equipment. As previously stated, the premise for the development of this process was the production of tabletops. While there have been technical challenges in this area, particularly in the firing stage, the extraordinary green strength of products produced through this process negates many of the handling issues involved in the manufacture of larger than normal sizes. Slabs as large as 40 in. (100 cm), both with and without surface detail, have been successfully produced in a small manufacturing facility using this process.
Flexible ManufacturingThe process is designed to require a minimal capital investment and to be easily scalable as the production volume increases or decreases.
The dry material ingredients are supplied as powders that can be stored in a silo and easily dispensed in measurable quantities for a batch or continuous production process. (The price of the dry material is commensurate with current dry clay prices.) The measured powder batch is dry blended and transferred to the mixing/extruding stage, where it is simultaneously injected with the proprietary liquid phase that contains the water and setting agents. The material is then dispensed into flexible tooling (i.e., non-porous or vacuum-formed molds) on a production line to produce multiples of the same product or a range of different products.
Much of the equipment used in the process would already be in place in many manufacturing facilities, or it could be easily obtained at a minimal cost. For example, small-scale or one-of-a-kind operations would simply require a planetary mixer, equipment to transfer the mixed material to the mold, and a vibrating bench to level the material in the mold. Large-scale operations could use a combination mixer/pump/extrusion machine to automatically mix and dispense the material to the molds. A vibrating bench would then be used to level the material in the molds, and a conveyor system would transport the products to the kiln.
Both the size and volume of products can be adjusted as needed, and production output can be easily accelerated through the use of variable speed drives. In a large production operation, the curing process takes place rapidly as the product moves along the line. The product is then removed from the mold, inspected, and transferred to the kiln for bisque firing.
The firing cycle depends on the volume and size of pieces being fired but is comparable to the firing cycles of other whiteware ceramic bodies in conventional tunnel kilns. Trials have shown that pieces produced through this process can also be successfully fast fired in roller hearth kilns. The fired pieces can then be glazed and returned to the kiln for a second firing.
An Innovative ApproachThis new, highly flexible process presents some exciting opportunities for the ceramic industry. It can be implemented as a stand-alone operation or as an incremental capability to an existing manufacturing plant. The process enables the user to emulate or create virtually any form, with only 1% loss in size/definition, in a variety of finishes, colors and surface treatments.
The technology has recently been brought to the U.S., where its full potential is being explored. Further research and development are under way with the assistance of Alfred University's Center for Advanced Ceramic Technology (CACT), Alfred, N.Y. In addition to efficiently producing high-quality ceramic products for architectural applications, initial findings show that the process might also provide advantages for high-temperature/high-tech applications fired at 1300-1500 degrees C (2372-2732 degrees F).
In increasingly challenging times, embracing innovative ideas can provide companies with new growth opportunities. For today's ceramic industry, this new manufacturing process is worth investigating.
For more information about the Danteceramic Process, contact Eric Cossich at firstname.lastname@example.org.
More information about Commonwealth Scientific Industrial Research Organization (CSIRO) can be found at http://www.csiro.au, and more information about Alfred University's Center for Advanced Ceramic Technology (CACT) can be found at http://www.nystar.state.ny.us/cats/Alfred.htm.