VUTRAX Application: Medical Research

The Medical Research Council is constantly at the leading edge of science. Its various departments often have to design and build their own equipment for research projects, because commercial products are not available.

This places many demands on the technical staff: design, development and manufacture of electronic hardware; writing of software; mechanics of housings; engineering of moving parts. New equipment has to be tested, which may need the manufacture of test rigs and the writing of diagnostic software, while operational equipment periodically has to be serviced.

It all adds up to a constant demand for PCBs.

In the MRC Laboratory of Molecular Biology (on the outskirts of Cambridge), VUTRAX PCB design software plays a key role in these developments. Mike Thompson, Higher Professional and Technology Officer, says: "VUTRAX is so much in demand, there is often a queue to use it. Design-on-paper has been virtually dispensed with and this software is used from the very start of a project."

A typical development was a colony picker, which automated the process of selecting individual cultures from a colony on a micro-titre plate. It releases experienced scientists and technicians from this routine task and enables them to analyse more cultures.

Six PCBs had to be developed, including those to control the robot picker. 6" by 4" micro-titre plates are held in six columns of 14, on a motor-driven carousel with a sliding arm to select individual plates. A vision system selects individual cultures and the robot lifts them out (using a sterile picking needle), then places them on a new culture plate. The needle is sterilised before picking the next culture.

Electron microscopy is another area covered by the diversity of projects in the department. A camera was developed using a charge-coupled device (CCD) to collect electron diffraction patterns.

Two multilayer PCBs had to be developed. A four layer board provided both the timing signals to synchronise the CDD and the space for 2 MB of memory to store images. A six layer PCB carried analogue-to-digital converter (ADC) chips to process the analogue output from the CCD, which operates in slow scan, low noise mode.

LMB has mechanical workshops as well as its electronic facility, which includes software development capabilities and a CAD system for designing Altera Programmable Logic Devices (PLDs). It can manufacture simpler PCBs in-house, up to double Eurocard size. Plated through hole and multi-layer boards are subcontracted. VUTRAX is used to create Gerber camera-ready files which are sent via a modem to the manufacturer, cutting down further on paperwork.