Laser/Piezo Autofocus System Offers Flexibility

Engineers at Motion X and Physik Instrumente (PI) have developed a laser-based system that combines Motion X's high-bandwidth autofocus sensor with PI's piezo-driven Pifoc objective and Z positioners. The modular and configurable architecture avoids image degradation and is suitable for commercial and custom microscopes and for substrates ranging from wafers with sensitive coatings to live biological samples. Achieving and maintaining a sharp focus can be a critical task for systems engineers and researchers.

Autofocus is important for users of standard microscopes and designers of custom optical columns alike, and some applications require real-time autofocus during processes in which the substrate is moved. Several approaches have been popular but can present drawbacks. Probe-based mechanisms compensate for drift by measuring the position of the sample plate versus the optical column, but are slow, cumbersome to set up, and limited in effective resolution due to the problematic probe/sample mechanical interface.

They also only maintain a mechanical setpoint and cannot correct for variations in sample thickness, drift between the probe and sample, parfocality errors between objectives, drift in the optics or the column itself, and so on. By comparison, optical autofocus techniques have the advantage of evaluating the image via the optics. All mechanical, thermal and optical issues which can impact focus, including changes and steps in the sample itself, are compensated. The teamwork between PI and Motion X joined Motion X's Focustrac system to PI's controls and piezo mechanics for plug-and-play autofocus capability.

PI's Pifoc piezo objective and z positioners are said to be typically 10 times faster than stepper or servo focusers and can realise full bandwidth capability of the Motion X laser autofocus technique. Different laser wavelengths are easily accommodated, the companies said, and mechanical options include objective positioners, turret positioners, sample-positioning and (well-plate) Z-stages and cost-effective OEM Z-positioning elements.

Process Analyser Offers Application Flexibility

The Applikon Analytical ADI 2040 process analyser from Metrohm is a multipurpose wet chemical analyser designed to offer flexibility and withstand harsh environments. The analyser uses techniques including titration, colorimetry and dynamic standard addition with ion-selective electrodes. The analyser's rugged hardware and the possibility to do automatic calibration and cleaning result in a 99.5 per cent up-time, according to Metrohm.

Its versatility allows the incorporation of multiple analyses and multiple sample streams on one analyser, resulting in low cost per analysis/sample. The controller makes it possible to run up to three independent analyses simultaneously. Reagent usage is minimised by using low-volume measuring cells. The ADI 2040 has a modular wet part with 20 uniform positions for a variety of modules and accessories. It can be adapted to almost any application.

In the electronic part, the same modular concept is used, so that the I/O cards for control of the wet part and external communication (maximum 20) can be configured to the needs of the user. The ADI 2040 can be loaded with several analysis packages by flash card and can therefore be adapted to specific process analysis requirements. The ADI 2040 can handle four (different) electrodes or sensors; extension to eight is possible. The possibility to choose a combination of methods means that in many cases one single ADI 2040 will fulfil all analysis requirements.

Servo Drives Provide High Control Flexibility

TCP/IP-compatible servo drives from Baldor Electric have simplified the construction of an automotive component tester from Dynamic Testing and Equipment (DTE). The new machine fully automates the accelerated life testing of the flexible boot seals used to protect ball joints in automobile steering assemblies. The use of programmable AC servos - instead of conventional hydraulic actuators - provides a high level of control flexibility, enabling test parameters such as joint articulation angles to be varied on the fly.

Capable of testing up to six boot seals simultaneously, testing regimes can include continuous articulation of the ball joints, hot and cold brine sprays, elevated humidity levels and air temperature cycling from -25C to +80C. DTE's boot-seal testing machine employs two motorised movement axes - one vertical and one horizontal - each driven by a Baldor Motiflex e100 three-phase servo drive and servomotor fitted with a multi-turn absolute encoder. The precise feedback signals enable both axes to be programmed to absolute zero, facilitating optimal positioning of the machine's tooling for parts loading and unloading, and ensuring ease of start-up.

The servo drives are connected via industry-standard Ethernet to the test machine's host computer, which runs National Instruments' Labview software, and are controlled via TCP/IP using the built-in ActiveX commands in Baldor's Mint programming language. Designed primarily for automotive component manufacturers, DTE's boot seal testing machine can be used to influence component design, or to demonstrate conformance with end-customers' performance standards.