The Loxham precision laboratory is a 600 metre2 temperature-controlled facility (1°C control accuracy), which houses ultra precision machines for large free-form optics production, equipped to handle optics through instrumented cranes and holding devices.
The laboratory also houses an ultra high performance, large scale, 3m by 2m by 1m co-ordinate measuring machine. The laboratory contains equipment that has the capacity to grind, polish, plasma process and measure ultra precise free-form optics of up to 1.5m with unrivalled production rates.
Summary of applications
We offer large optics fabrication and a wide range of complex metrology services. These machines can be accessed for commercial and research purposes.
BoX® ultra precision free-form grinder (1500mm capacity)
BoX® is an ultra precision free-form grinding machine. With a compact and novel three-axes configuration, the machine is designed to manufacture large free-form surfaces cost effectively. The BoX® machine is capable of grinding and measuring parts of up to 2m in diameter due to a structural arrangement that allows it to be very compact. This machine is primarily designed for producing large precision optic components, and was built for the University by Cranfield Precision in 2006. One of the main design criteria for this BoX® machine was that it must have a very high dynamic stiffness. The machine's first resonant frequency is greater than 100Hz, which is a difficult feat to achieve for a machine of this size.
Helios 1200 is an energy beam figuring system developed by Cranfield University and RAPT Industries. HELIOS is a ‘first of its kind’ machine tool that operates at atmospheric pressure, whereby a plasma energy beam is used for final figuring of large ultra precision surfaces. The machine is devised to figure correct large glass and ceramic mirrors with nanometer dexterity. It offers a very rapid figure correction means having significant time and cost savings compared with established techniques such as ion beam figuring.
Leitz PMMF 30.20.10
The Leitz PMM-F is a high-accuracy monolithic gantry measuring machine for large workpieces with a traceable accuracy 1.9um+L/400 (typically 5.7um for a 1.5m component). It achieves high throughput with highest possible accuracy with a volumetric capacity 3m x 2m x 1m. The Leitz PMM-F measuring machine is equipped with an integrated active vibration damping system. It is housed in Cranfield University’s Loxham laboratory with temperature and humidity control systems. The Leitz LSP-S2 high performance probe head allows high speed scanning and can handle stylus lengths of up to 800mm.
RAPT 300 plasma processing system
A prototype reactive atom plasma surface figuring machine equipped with a plasma torch. RAP is a form of plasma-enhanced chemical etching at atmospheric pressure based on inductively coupled plasma technology. The rapid figuring capability of the RAP process has already been proven on medium sized optical surfaces made of silicon-based materials.
The ZYGO DynaFiz™ laser interferometer
The ZYGO DynaFiz™ dynamic laser interferometer is a highly optimised optical instrument designed specifically for performing accurate metrology of optics in the presence of air turbulence and extreme vibrations. The high light efficiency of the DynaFiz™ interferometer’s optical system, combined with its long life, high power and HeNe laser source, enables operation at high camera shutter speeds that 'freeze' vibration. This dynamic capability provides reliable metrology in environments that are too violent for traditional temporal phase shifting techniques.
HR4000 high resolution spectrometer
The HR4000 spectrometer is a versatile high resolution spectrometer which has a Toshiba 3648 element CCD array detector that enables optical resolution as precise as 0.2nm (FWHM). The HR4000 is responsive from 200-1100nm, but the specific range and resolution depend on the grating and entrance slit choices. This novel combination of optics and electronics is ideal for applications such as characterising lasers, measuring gas absorbance and determining atomic emission lines.
Using the facility
The Loxham precision laboratory has produced systems/components for:
- Space-based Earth observers,
Metrology services using the Leitz PMMF are provided under confidential contracts to leading UK and European organisations.