The main schematic capture and PCB layout program Bustronic uses is PCAD. PCAD was developed by Accel and later evolved into Altium. The latest version of PCAD is 2002. See www.acceltech.com. Many of our backplane designers both in the USA and Europe use PCAD as it is well-known and reliable.

As switched fabric backplanes are on the rise, Bustronic has gained more software resources for complex and higher layer count designs. We have access to Mentor's Design Capture for schematic capture and Expedition for PCB layout. A tool like Expedition is vital for routing switched fabric backplanes. Mentor provides interactive design capabilities, powerful auto-routing software for differential pair routing, net tuning and manufacturing optimization. See www.mentor.com/pcb.

After the backplane is designed and fabricated it's ready for assembly. In 2002, Bustronic expanded our production capabilities with a new SMT line. Not only did the expansion increase capacity, but the top-notch quality and consistency the new machines provide is impressive. The new SMT line is 40 feet long and has an in-line printer, SMT assembly machine, re-flow soldering system and a multi-solvent cleaner. The in-line printer handles the solder paste application on the stencils. The next machine in the line is a Quad IV pick and place machine. It has accurate alignment vision systems for precise component alignment and placement. Next, the board passes through the Vitronics XPM re-flow furnace. This solder oven is specifically designed for backplanes, and is excellent in achieving uniform solder re-flow for PCBs thick and thin. Last on the line is the AATC multi-solvent cleaner designed to wash, rinse and dry solder residue or other contaminants. Bustronic can also use our high-volume assembly line in Pforzheim, Germany. The assembly line is over 120' long and is used for special projects.

Once a backplane is designed, fabricated and assembled it goes to testing and quality assurance. The main testers we use are an Adaptronic NT 910 Backplane Test System and a Weetech 3504, both PC-based. The testers check all nets on a backplane for continuity, opens and shorts. The bypass capacitors are checked and any missing devices or incorrect values are found. For VME backplanes, they verify all termination networks are inserted properly, are the correct value and within tolerance.

The Weetech tester uses a daisy-chain switching matrix distributed over "flying cassettes." The flying cassettes are printed circuit boards with test points and backplane mating connectors. The cassettes are plugged directly into the backplane under test without additional cables or adapters. The measuring accuracy is improved significantly due to the minimized distances between the test points and the backplane connectors. The Weetech can be hooked up to a network and can self-learn from a known good backplane or be manually programmed. It can test resistors, capacitor, diodes and zener diodes.

The Adaptronic tester has a network connection allowing engineers to download and upload test programs on the PC without disrupting backplane testing. Test programs can be generated from netlists created by our CAD software. The NT 910 offers testing capabilities for resistors, capacitors, diodes, zener diodes and LEDs (light emitting diode). With its Windows-based software, the NT 910 can either self-learn from a known good backplane or be manually programmed. The lists of pin connections can be named in different tables for ease of debugging, for example P101-B09 could also be named BD_SEL#, or Slot 1 BD_SEL#. It also has a built in multimeter for debugging.

Not only has Bustronic incorporated all of these design, testing, and manufacturing upgrades, but we have expanded our sales and support. The company has opened an East Coast Office for sales and application support in Chelmsford, MA with our parent company Elma Electronic. In addition to sales support staff there, we've hired well-known industry expert Michael Munroe. Along with our new Field Application Engineers, Michael will help provide technical service and support and help expand our East Coast operations.

If you would like more information on Bustronic's equipment, capabilities, or support, contact us at info@bustronic.com

Melissa Heckman
Electrical Engineer