Prototype PCBs made fast and clean
David Bak, Editor-in-Chief, Global Design News -- Design News, July 15, 2001
Glasgow, Scotland —Frustrated at not being able to quickly and cost-effectively source a printed circuit board prototype for an alarm system he was developing, Scot Godwin Osibwe took matters into his own hands. Osibwe founded Sigtronics Ltd., a company dedicated to producing low-cost, low-volume, prototype PCBs. Its Quickboard™ Service Centre, launched at NEPCON 2001 in Birmingham, England, guarantees fast turnaround—within 24 hours to anywhere in the U.K.
Normally, the typical design office of two to ten engineers will ship its CAD files to a traditional PCB manufacturer. Then it must wait while the PCB manufacturer tools up and books a slot on the production line. This procedure can take days, and sometimes weeks.
Sigtronics' alternative Quickboard technology enables designers to go from initial drawings to final design in hours. Three stages make up the process:
Stage one. Load the Gerber PS 274X or 274D files into the control center. Following instructions provided from the control system, the machine operator first places a piece of industry standard substrate on the layout station. Lowering the cover on the layout station starts the process.
Routing, where the circuit pattern is applied to the blank substrate, is totally automated. The milling is carried out by a hardened routing bit driven by a 120,000 rpm spindle running on an air bearing. Precision grooves, between 35 and 100 mm deep, are cut using real-time depth-controlled routing. To accomplish this, the Sigtronics team has engineered a precision Z-axis wrapped up with their proprietary software.
Circuit pattern engraving, moreover, is a dry process that does not involve chemicals. This additive process is faster and less wasteful than the traditional reductive method using copper clad boards.
Stage two. Those familiar with the assembly process know that solder paste application can be tricky. Quickboard is more straightforward and does not require a stencil. A conductive copper polymer, developed by NASA and the U.S. military, is applied as a flood across the track area and is then wiped clean off the top surface. The system allows precision adjustment of wiping force, angle, and speed.
Stage three. After the holes and grooves are filled, curing takes place using a proprietary system. At this stage, the conductive material needs to be irreversibly 'kicked over' into a conductive plastic. The material contains a combination of activators and flux so they are almost entirely incorporated into the cured polymer, leaving only small traces of solvent to release.
The Quickboard Service Centre is designed for low volume users. However, those companies that have a high demand for prototyping, or simply prefer to keep PCB prototyping in-house, can purchase the Quickboard Printer. For more information, go to http://www.sigtronics.co.uk .
For more information about Quickboard technology from Sigtronics:Enter 564
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