What makes technical ceramics so challenging to cut & drill?
The term “technical ceramics” encompasses a range of inorganic solid materials with a host of unique and desirable characteristics. Mechanically, they possess both compressive strength and high hardness, giving them excellent wear resistance and dimensional stability. They are electrically insulating, but also thermally conductive in some cases. They can function at very high temperatures without degradation, and they are chemically inert and resistant to corrosion. As such, technical ceramics are used to address particular engineering challenges in applications from aerospace to electronics.
For example, alumina (Al2O3) is commonplace in the electronics packaging industry, where it serves as a substrate for components including photovoltaics and high brightness LEDs. Alumina possesses high strength, excellent electrical insulation properties, and good thermal conductivity. Conversely, the challenges of working with technical ceramics are also well-known; the intrinsic properties that make them so useful pose distinct manufacturing challenges. This blog post will explore what makes technical ceramics challenging to cut and drill, and what other manufacturing options are available.
Why are technical ceramics so challenging to cut?
Technical ceramics are generally sintered from inorganic materials, yielding fired parts that usually require machining in some way – for example cutting, drilling, or scribing. The extreme hardness of the fired ceramics presents a problem for any kind of mechanical machining process. Although possible, traditional machining processes, such as cutting, drilling and milling, require diamond tools. These tools have a limited life cycle and have to be replaced on a regular basis. In some cases machining technical ceramics could induce mechanical stress. As ceramics are brittle materials, this could result in fracture. To preserve the mechanical integrity of the machined ceramic, a subsequent “heal fire” and stress-relieving sintering process may be needed. For thin ceramic components (a few millimetres thick), tooling and additional post-machining processes add significant cost and time to the manufacturing of the finished product. So, what is the solution?
What machining techniques are suitable for technical ceramics?
Some of the non-conventional machining methods available for ceramic cutting include abrasive water jet (AWJ), electrical discharge machining (EDM) and laser-assisted milling (LAM). All of these have both advantages and disadvantages, a detailed discussion of which is beyond the scope of this article.
Laser processing of technical ceramics, whether cutting, scribing or drilling, is attractive because it is a precise and cost-effective method. The hardness of the material presents no problem, and the non-contact nature of the laser process means there is no tool wear, thus minimising downtime and eliminating the associated costs of tool replacement.
The carbon dioxide (CO2) laser is well-suited to processing ceramics, particularly the alumina wafers used in the electronics industry. Thin sheets can be divided by scribing, where the laser drills a series of closely spaced blind holes in the ceramic, penetrating roughly one third to a half of the thickness of the ceramic. The material is weakened along the scribed line, and can be mechanically broken to separate the components. Each hole is drilled using a single laser pulse, while the depth is controlled by the pulse duration; pulses up to 1ms are commonly used.
Thicker ceramic can be cut with very good edge quality, although this process is slow. High average powers do not necessarily lead to faster machining, due to plasma screening effects; in these applications, the laser pulse regime is critical. Pulse duration, peak power and pulse energy must be carefully controlled in order to minimise plasma absorption and maximise efficiency of material removal. Even with this high level of control, laser machining can cause heat build-up and mechanical stress in the ceramic material, and the process parameters must be chosen carefully in order to mitigate the risk of fracture.
Looking for CO2 laser sources?
At Luxinar, we have been manufacturing CO2 laser sources for 25 years. Our lasers are used globally for applications including electronics, medical devices and automotive components. They can be used to process a wide range of materials, including ceramics, plastics, textiles, paper, sheet metal and more. Our CO2 laser sources are designed for integration into industrial machines, where they can operate in harsh environments. Our SR series laser sources are particularly well suited to ceramic processing applications, including cutting, drilling, substrate dicing and scribing.
You can find further product details in our industrial range brochure, or contact us today for more information on ceramic cutting methods for technical ceramics or any other questions you may have.
Visitors discover “phenomenal” laser production speeds
On 30 July 2019, Paul Bell, Head of Development at East Riding of Yorkshire Council, and Liz Johnson, Business Development Manager at Hull University, visited the recently rebranded Luxinar facility (previously Rofin-Sinar UK). They were given a tour of the purpose-built high-tech facility, including observing the latest technology being developed in the R&D cleanrooms and visiting the applications laboratory, where they were given demonstrations of Luxinar’s lasers in action.
They were amazed at what could be achieved within the 80000 square feet (7432 square metres) of Luxinar. The self-contained manufacturing facility includes both R&D and manufacturing space, with its products being shipped and installed globally across a wide range of industries.
“It’s phenomenal really in terms of the speed at which a laser can be used to speed up production lines,” remarked Paul Bell, Head of Development at East Riding of Yorkshire Council.
More photos can be found at www.lasersforindustry.com
Local MP Emma Hardy visits Luxinar
On 5 July 2019 Emma Hardy, MP for Hull West and Hessle, visited newly branded Luxinar, previously Rofin-Sinar UK. Emma was welcomed by Russell Jeynes, Operations Director, who led the tour of the facility.
Russell explained the company’s capabilities and its focus on developing laser technology to enhance our world, at the purpose-built facility at Bridgehead Business Park, Kingston upon Hull. The tour began with a summary of how, over the last 20 years, Luxinar has become renowned for its industry-leading sealed CO2 lasers and power supplies that are used for a myriad of applications in industrial processing and marking applications worldwide.
Emma was then given an overview of the production, service and engineering departments, as well as a brief insight into some of the ongoing R&D innovations. “I never knew it would be so intricate to fine-tune the lasers”, she remarked, when observing a 450W laser being aligned to increase the power with some small mirror adjustments.
In the company’s purpose-built applications laboratory, Emma saw end-user product samples where Luxinar lasers had been employed in a variety of ways. These included cutting, drilling, welding and marking of plastics, metals, fabrics and ceramics, for products spanning the textile, beverage, labelling, packaging, and automotive industries, to highlight a few.
Emma Hardy MP said of her visit, “I never knew that lasers could do that; it’s like Doctor Who, it’s so futuristic!”
China delegation visits Luxinar, Kingston upon Hull, UK
Guangdong Laser Industry Association included Luxinar, global leader in laser technology, in their tour of European laser suppliers. On 2 July 2019, ten Chinese delegates from the Guangdong Laser Industry Association visited the recently rebranded Luxinar, previously Rofin-Sinar UK, on the UK part of their wider European tour of key suppliers in the laser industry. The delegates, mainly Executive Directors and General Managers, were from a variety of manufacturers within the Chinese laser industry, including the largest laser chiller and laser cutting head suppliers in China and laserfair.com, the most popular newsletter in the Chinese laser industry.
This was an ideal opportunity for Luxinar to demonstrate the company’s capabilities and its focus on developing laser technology to enhance our world, at the purpose-built facility in Kingston upon Hull. The delegation toured the manufacturing facility that has, over the last 20 years, become renowned for its industry-leading sealed CO2 lasers and power supplies that are used for a myriad of applications in industrial processing and marking applications.
The tour began with an overview of the production, service and engineering departments, as well as having a brief insight into some of the ongoing R&D innovations. In the company’s purpose-built applications laboratory, the delegates saw first-hand end-user product samples where Luxinar lasers have been employed in a variety of applications including cutting, drilling, welding and marking of plastics, metal, fabrics and ceramics, for products spanning the textile, beverage, labelling and packaging, and automotive industries, to highlight a few.
“More than 35% of laser sources from Luxinar are now installed at manufacturing and production sites in China,” explained Andrew Chambers, Sales Director. “The visit from Guangdong Laser Industry Association is an ideal opportunity for us to demonstrate and reassure that although our company name has changed from Rofin-Sinar UK to Luxinar, the products, technology and people behind the new brand remain the same. We continue to manufacture the same high-quality products and continue to support our Chinese customers locally. We have supported our Chinese base for 20 years within China, and have recently enhanced our capabilities from our regional office, now based in Shanghai for the last 2 years”.
As the Guangdong Laser Industry Association left for their next company visit, they told Andrew Chambers they had enjoyed their time at Luxinar and found it extremely informative.