When Micrometers Are Not Accurate Enough

LT Ultra uses measuring machine from Carl Zeiss to measure components for telescopes and lasers

When the European Space Agency (ESA) is preparing a space probe for a journey through the cosmos, one thing has top priority: precision down to the last detail. LT Ultra, a manufacturer of high-precision metal optics, guarantees this precision with measuring technology from Carl Zeiss.

The challenge: pure precision

Seven years in space, temperatures ranging from minus 40 to plus 300 degrees – Europe's first mission to Mercury will certainly be no walk in the park. Therefore, all parts traveling in 2014 must meet special requirements. This applies in particular to the altimeter that will map the surface of the planet. Its components include the baffles, aluminum parts that will protect the laser and telescope from the rays of the nearby sun. In a multi-step process using an ultra-precision lathe, LT Ultra-Precision Technology GmbH in Herdwangen-Schönach, Germany, manufactures the components of the baffles which are just several tenths of a millimeter thick.

The company specializes in ultra-precision machines: machine tools featuring accuracy down to the nanometer and sub-micrometer range. However, this alone is not enough: "High precision is not possible today without the corresponding measuring equipment," explains Richard Widemann, President of LT Ultra.

Parts such as baffles present the measuring technology at LT Ultra with certain challenges: the thin-walled components have an extremely sensitive optical surface that is easily scratched and must be measured with accuracy of a few hundred nanometers.

Solution: PRISMO ultra

In order to meet the high demands on accuracy and sensitivity, LT Ultra acquired a PRISMO ultra coordinate measuring machine from Carl Zeiss – with a special configuration. The standard PRISMO ultra measures with accuracy of 0.6 micrometers. However, even this amazing precision is insufficient for special items such as the baffles.

By using hand-selected components and perfecting the already very careful assembly, Carl Zeiss succeeded in tailoring the measuring machine to the extraordinary accuracy requirements. Furthermore, the experts at Carl Zeiss therefore optimized the control parameters of the controller for the contact sensor and modified the software settings for the special job. Now, the contact stylus touches the workpiece ever so slightly, ensuring that the sensitive surface is not damaged.

Benefit: High-precision, on-site measurement

"This measuring machine is a milestone for us," summarizes Wideman after one year. Since the introduction of the PRISMO ultra coordinate measuring machine, LT Ultra measures the complex geometries with their high accuracy requirements internally. The company is no longer reliant on external providers which considerably slowed processes in the past and made some projects impossible. Who knows if products from LT Ultra would have ever made the trip to Mercury without the investment in a measuring machine.

About the company

With its 70-strong team of employees, LT Ultra-Precision Technology GmbH is a leading manufacturer of high-performance metal optics, ultra-precision machines, air bearing components and beam guidance components for lasers. Products of the company, founded in 1995, are used in luggage scanners at airports or required by the CERN Institute for the construction of a new type of particle accelerator. The company therefore has access to various market niches.