Lightweighting: Untapped Opportunities in Ceramics
Cutting energy consumption has to be a key priority for the industry.
Energy-intensive industries such as ceramics have been hit hard by rising gas and electricity costs over the past five years. The next 10 years will see prices increase further, and taxes and rules aimed at emissions reductions will add significantly to the financial burden faced by the sector. In the UK, for example, the British Ceramic Confederation has warned that the cumulative effect of climate change policy will put some firms out of business, while others will move to countries with less stringent green regulations and tariffs.
Energy bills in the sector can account for more than a third of total production costs, so cutting consumption has to be a key priority for the industry.
Lightweighting vs. Rightweighting
Lightweighting—making a product lighter by using less material or different materials, without compromising performance—is one area that ceramic producers can look to in their efforts to curb costs and emissions. The performance characteristics that a product needs to be successful in the marketplace are generally well understood from the start of the design process. A brick, for example, must be strong in compression so that it can bear load without breaking; durable to the environment so it has longevity and does not crumble; thermally stable so heat is not conducted too easily; water resistant so rain does not penetrate; and of regular size so that walls can be built uniformly.
One characteristic that is not often considered in the design stage, at least in the ceramic and heavy clay industries, is the weight of a product. Lightweighting has been embraced by other sectors for some time. In aerospace, lighter components are used to make aircraft that can go faster or use less fuel. In defense applications, meanwhile, less weighty body armor has been developed. In both cases, the maintenance of product performance is critical: the body armor may be lighter, but it must still be able to protect someone
The concept of rightweighting, which takes into account the costs involved in making a product, is now being adopted by manufacturers in other areas. Although making something lighter often reduces costs, it is not always the case. The key is making the item the right weight to retain characteristics and performance while enabling production at the correct cost point (which is not necessarily the same thing as the lowest cost).
In some cases, the food industry has replaced more costly ingredients with water. Dropping expensive ingredients reduces production costs, while the addition of water can make an item the “right” weight to maintain prices over the counter. Such methods may not sit comfortably with some manufacturers or consumers, but at a time of rising input costs and fragile consumer spending, it has been an effective method of protecting margins and revenues.
How useful could lightweighting/rightweighting be for the ceramic industry? What value could be gained by manufacturers looking to differentiate themselves, grow market share, reduce costs and increase profitability?
Ceramics covers a vast array of products and applications, but the majority of output is driven by product functionality and performance. Weight is often purely incidental—a result of how something is—and always has been—made.
Consider tableware for the hospitality market. Items must be aesthetically pleasing, but the key attributes for the customer are durability and strength. Ware needs to be able to withstand many hundreds of washing cycles in industrial dishwashers. It also needs to be strong but not brittle to tolerate bulk transport around venues without chipping or breaking.
Traditionally, these requirements have led the industry to focus on bulk, mass and thickness. But could the product characteristics of strength and durability be maintained in a lighter product that uses less material, requires less energy to be manufactured, and is lighter to move around internally and to transport? If so, the benefits to manufacturers could be great: less material, less energy, less transport. All these factors mean less cost and improved profitability—vital methods of thriving rather than just surviving in an economic downturn. At the same time, the user benefits in terms of moving and handling issues, so lightweighting can be a win-win for users and manufacturers alike.
Lightweighting is a simple concept, but putting it into practice is more complex. To make real gains—rather than incremental savings—requires a more revolutionary approach, innovative thinking, and a desire to learn from other technologies and industries.
On a related note, lightweighting may reduce costs, but changing manufacturing processes could involve a significant capital sink. Cost/benefit analyses must therefore be rigorous and accurate. This is where rightweighting comes to the fore. Rightweighting makes the product the correct weight to satisfy all criteria, including performance characteristics, direct manufacturing costs and cost-reduction benefits.
For the ceramic industry, a sound knowledge of technologies such as powder processing could be important for rightweighting projects. Characterizing and then controlling different powder particle chemistries in the dry and suspended state will lead to a more homogeneous sintered microstructure. This, in turn, will deliver superior mechanical properties—or equivalent mechanical properties in products with thinner cross-sections.
In addition, understanding powders can lead to the partial substitution of traditional materials. The use of recycled materials, lower cost materials, or materials with a lower melting point or specific gravity, for example, could boost both profits and green credentials.
A second important aspect for the ceramic sector is the use of computational modeling to investigate novel geometries. Once improved properties, such as fracture strength, are associated with a superior powder microstructure and have been quantified for simple shapes, the data can be used in finite element analysis models. Different geometries featuring lower weights can be run through the model and checked for unwanted stress development as loads typically experienced in use are applied. The most promising shapes produced by the modeling can then be assessed through production trials and stress testing.
Lightweighting is not an entirely new concept for ceramics. Challenges in the UK tiling sector include aggressive foreign competition, rising energy transport and materials costs, and materials sourcing challenges. Making tiles that are lighter, contain less or different materials, use less energy, and cost less to transport helps to address these issues—as long as changes do not harm characteristics such as durability and water absorption.
Two approaches to lightweighting have been taken by tile makers: the use of foaming agents and design changes. Foaming agents create air-filled voids that reduce the weight of the finished product and enhance thermal insulation properties. Agents such as silicon carbide can help produce tiles that are up to 26% lighter while maintaining appropriate mechanical strength and water absorption. In addition, the use of foaming agents allows firing temperatures to be lowered and the expansion process to increase. This enables lower firing temperatures, which reduces energy consumption and bills.
Design has also been used to lightweight tiles. Back reliefs, or apertures on the reverse of the tile, have been used to cut weight by between 2-31%.
The potential environmental benefits of lightweighting (reduced emissions associated with making, moving and recycling product, reduced water usage, and so on) can be a valuable part of the marketing mix. Consumers are now paying more than just lip service to environmental credentials, and illustrating practical steps to cut energy use and greenhouse gases can help win contracts from clients in both the private and public sectors.
The financial markets have followed suit, evaluating the risk to businesses of exposure to climate change and environmental issues. With rankings such as those in the Carbon Disclosure Project and Newsweek, the interest from stakeholders and investors can only grow.
So far, ceramics have only scratched the surface of the potential for lightweighting, but the benefits could be far-reaching in a truly global marketplace. With this tool, ceramic companies could improve profits and environmental performance—but it requires commitment, some lateral thinking and a passion for learning from other industries.
For additional information, visit www.ceram.com/lightweight.