Alumina ceramic (Al2O3) is used to manufacture many items, including medical prostheses, ballistic armor, laser tubes, and circuit boards.

May 1st, 2012

Standing the heat: Laser processing alumina

Rugby, UK — Alumina ceramic (Al2O3) is used to manufacture many items, including medical prostheses, ballistic armor, laser tubes, and circuit boards. Its popularity is due to its strength, durability, corrosion resistance, thermal stability, and excellent dielectric properties. These characteristics also make Al2O3 difficult to process — while strong in compression, the material is prone to cracking from thermal stress, and traditional techniques such as diamond grinding can be costly and time-consuming.

FIGURE 1. (top) 1 mm alumina ceramic (96%), 300 mm/min, air assist gas; (bottom) Trepanned hole (0.5 mm dia.), 0.6 mm alumina ceramic (99.7%), 200 mm/min, air assist gas.

Rapid technological advances mean it is now possible to use Nd:YAG and fiber lasers to achieve a high standard of finish, providing the necessary levels of control using variable parameters such as spot size, peak power, pulse duration, and frequency.

Optimized laser and processing parameters help minimize heat input, significantly reducing the risk of thermal stress, which can lead to cracking. Large scattering of the laser beam, which can be seen at some common wavelengths, can be overcome through a combination of high peak power, short pulses, and short wavelengths (1 µm).

For example, JK Lasers’ single-mode 200 W fiber laser (JK200FL) with built-in modulation can achieve good quality cuts in Al2O3 up to 1 mm thick (FIGURE 1). It is possible to achieve pulse widths as short as 5 µs by gating at a high frequency (50 kHz); depending on the purity of the alumina, this can provide dramatic improvements to process quality.

FIGURE 2. (top) 1.2 mm alumina ceramic (96%), 250 mm/min, air assist gas; (bottom) 0.5 mm alumina ceramic (99.7%), 650 mm/min, air assist.

FIGURE 2 shows examples of edges that have been cut with a lamp-pumped pulsed Nd:YAG laser (JK100P). The combination of high peak power (10 kW), short pulses (15-200 µs) and high repetition rate (2000Hz) make this laser well-suited to cutting Al2O3 up to 2 mm thick. It is possible to cut up to 3 mm with multi-passing.

The results demonstrate that both fiber lasers and lamp-pumped pulsed Nd:YAG lasers can machine Al2O3 between 96%–99.7% purity. With no evidence of micro-cracking or dross along the cut edge, these lasers offer manufacturers a viable alternative to traditional processing techniques.

For more information, visit www.jklasers.com.

Cutting seats for Land Rover

Tipton, West Midlands, UK — CAB Automotive is a privately owned Tier 1 supplier of interior trim parts to the automotive industry, with capabilities including product engineering, development, manufacturing, and assembly of automotive headliners, interior trim, parcel trays, seating and trunk trim, and rail seating solutions for mass transit carriage, railcar, and coach. CabAuto manufactures components such as the parcel shelf for the Jaguar XF; molded carpets and headliners for Aston Martin; and seating, headliners, and bespoke storage solutions for the Land Rover Defender.

The company previously subcontracted out its entire laser cutting operations, but decided that commercial factors made it favorable to move this work in-house. It chose a Bystronic laser from World Machinery and Lantek Expert CADCAM to nest the parts and create the CNC programs. With the Bystronic laser cutting system, CabAuto can now do all its laser cutting in-house.

The principal project for which the laser system is used is making seating components for the Land Rover Defender, making 10,000–15,000 parts each week, with material ranging from 1–8 mm thickness, in steel, aluminum, and Hypress steel, explained manufacturing engineer Lee Macdonald. “Once the components have been cut, the parts are formed, welded and assembled, to make the seat frames. Due to the fast-moving and cost-sensitive nature of our business, we need to achieve rapid and reliable CNC programming and high levels of material utilization,” he said.

The Lantek software allows both automatic and manual nesting, and its parallel processing technology gives speed improvements of at least 30%. During nesting, the system considers material type and thickness and can manage kits of parts — nesting parts within one another if possible — and manage the reuse of offcuts through a database to optimize material utilization. Features in the software can save both material and time by reducing wasted moves on the laser, increasing the number of parts in a sheet, and speeding up the handling of components once they have been cut.

From its 110,000 ft.2 facility, CAB Automotive turns over in the region of £24 million and is a major employer in the area. It is accredited to ISO/TS16949 and ISO 14001, and operates fully in accordance with established automotive procedures. The company maintains a well-equipped on-site laboratory alongside extensive CMM facilities and a modern BSR testing rig. Capabilities include product engineering, development, manufacturing, and assembly of automotive headliners, interior trim, parcel trays, seating and trunk trim. The firm also does rail seating solutions for mass transit carriage, railcar, and coach.

CabAuto’s performance as a world-class interior component manufacturer is built upon a recognizable culture of quality driven by a passion for innovation, durability, and refined comfort.

Fast prototyping brings lighting products to market quickly

Rochester Hills, MI — A lighting manufacturer set itself the task of leading what it calls “the LED lighting revolution,” aimed at making traditional energy-intensive lighting technologies obsolete with a line of LED architectural lighting products that allow optimal distribution of light with minimal power consumption, incorporating breakthroughs in optical, electronic, and mechanical design as well as thermal management. A growing number of companies are seeking to establish themselves as players in this young market, so this company knew it had to quickly get its new lighting product to market.

Essential to that aim was getting the required prototype parts, and that help came from 3-Dimensional Services. The firm specializes in design, engineering and analysis, in-house tool construction, and complete build of prototype first-off parts and low- to medium-volume production runs, which enables them to provide actual prototype parts up to 70% faster than conventionally equipped prototype shops.

While the company created the lighting modules for the new product line, 3-Dimensional Services was tasked with creating the metal fixtures that would house them. Low-carbon steel blanks were laser cut to near-finish dimensions on one of their 5-axis lasers.

Three different sizes of fixtures were needed, the largest of which measured 2 x 4 feet, which required three different forming tools. Three 3-piece forming tools consisting of punch, die, and draw ring were designed. Machining programs were generated from these designs and offloaded to the company’s CNC machines, and developed from the resulting designs. The parts were cut from aluminum rather than from tool steel, because the softer metal could be machined faster, very accurately, and to a high-quality finish — for the parts’ intended environments, they needed to have a Class A finish, with no wrinkles, nicks, or flaws.

Next came forming on three of 3-D’s numerous presses, from 20 to 75 for each of the three sizes, which were taken back to a 5-axis laser for final trimming. The parts were then transferred back to the hydraulic presses for secondary bending operations, in which some of the trimmed edges were flanged or hemmed — this required three bending tools (one for each part size), created using the same technology and with the same speed as the three original forming tools. The parts underwent final checks, then were powder coated and shipped. All of this was accomplished within the 3-4 week timeframe the customer had specified.

3-Dimensional Services Group consists of 3-Dimensional Services, Urgent Plastic Services, and Urgent Design & Manufacturing. Together they design, engineer and build functional prototype parts and low- to medium-volume production parts faster than conventional prototype shops. For more information, contact the company at www.3dimensional.com.

3-Dimensional Services created three different tools along with three additional tools for bending operations, plus other processes, to produce the LED light fixtures.

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