Bosco (www.bosco.co.za), by far the largest PCB manufacturer in South Africa, was first established in 1956 as an anodising business and the first one-sided boards were produced manually in 1966. Bosco acquired a new facility in 1997 with a floor space of 16 000 m² but after a R7 million refurbishment of the premises, Bosco started off utilising 8000 m²², the rest of the premises being leased to other electronics companies, including one of its customers.
The company was established by H.G. Verheul and he took great pride in the fact that Bosco Printed Circuits was the first facility in this country to manufacture PCBs.
Today, it is his three sons who own and manage the business, the managing director being Peter Verheul, who had joined his father in 1978. The company has a staff in excess of 100 people and has focused all of its efforts on single and double-sided boards only. Bosco is the largest manufacturer of PCBs in Africa, and its growth has been fuelled by the drop-out of other non-competitive local suppliers. Its objective is to produce small to medium production runs. For larger volumes it has an arrangement with an ISO 9000 and UL certified facility in the Far East that can supply large quantity production runs at competitive prices, this including multilayer PCBs (these products can be supplied on a variety of base materials including FR-4, CEM-1, CEM-3 and FR-2).
The layout of the new plant (the old facility in Sebenza was only 2500 m²) is spacious and there is lots of room for further expansion. As dust and dirt are a major enemy of the PCB manufacturer, particularly with high density surface mount boards, critical parts of the facility are maintained with over pressure to Class 10 000 clean room specifications. Card-controlled sliding doors provide access to the critical production areas and close shut on secure rubber seals. Peter Verheul believes "that if you want to play in the big league you do not skimp on your equipment and protection".
The products offered by Bosco come on an FR-4 Base Laminate and include single- and double-sided through-hole plated circuit boards, SMT circuit boards, and from prototype to medium levels of production. Once again, the artwork should be Gerber format and Bosco can offer a conversion service through film scanning. Bosco also offers its CAD/CAM for use by customers. The process includes laser photo-plotting, CNC drilling and routing, liquid photo-imageable solder resists, hot air solder levelling (not lead-free) and panel V-scoring - which is 4-axis CNC-controlled. Testing includes an electrical bare board test and double-sided SMT testing (20 mil pitch) in large volume.
The maximum PCB size (base material FR-4 epoxy glass laminate) is 450 x 520 mm and the minimum hole diameter (PTH) is between 0,3 (subject to prior consultation) and 0,4 mm. For non-PTH holes the diameters can be down to 0,15 mm. Tolerance on hole diameter at these sizes is ±0,05 mm. The minimum conductor width is 0,18 mm with 0,2 mm being the preferred value. The minimum conductor spacing is the same. The plating thicknesses depend on material and are 20 μm minimum and 25 μm normal for copper, 1,3 μm for gold on nickel (edge connector), 2,5 μm for nickel and ±2,5 μm for hot tin-lead solder.
Bosco has several hundred local customers and these include leading names in many sectors such as Kentron (now Denel Aerospace Systems and Denel Optronic Systems, Grintek, Jasco, QD Electronics, Shurlok and MAMI. Sectors addressed include defence, security, telecommunications, automotive, control electronics and the contract manufacturers.
In terms of quality assurance, the final boards are tested before dispatch. The testing procedure itself is automatic with simple 'pass' or 'fail' output, and with a throughput of 600 full panels per hour. The skill comes in the assembly of the complex pin jigs used for the testing. This is also done in-house and the assembly work is a skilled and dextrous task. Like almost every employee at Bosco, training in these specific pin assembly jigs is provided in the plant as there is no technikon or university that turns out personnel with PCB manufacturing skills.
Bosco also possesses a R1 million Gerber laser photoprinting machine. This printer, which uses a scanning laser beam to 'write' the board photo-negatives, can operate at up to a resolution of 8000 dpi. In fact, for most of Bosco's jobs, 2000 dpi would be more than adequate, but to maintain quality and consistency the company operates standard practice writing at 4000 dpi.
A critical part of any PCB operation is chemical processing. Bosco employs a full-time graduate chemical engineer who runs his own laboratory. As for the chemicals, Bosco helps maintain consistency by purchasing all of its requirements from the US company MacDermid.
The company is proud of the fact that it is a long standing member of the IPC (Institute for interconnecting and packaging electronic circuits). The technical publications and notes from the IPC cover every facet of PCB manufacture and have proved invaluable to the local company in terms of allowing it to improve productivity, quality and consistency.
As for the name of the company itself, Verheul decided that his company would be named in honour of Saint Don Bosco, whose principal vocation was the sustenance and education of thousands of destitute children. The name Bosco is thus just as appropriate in the new South Africa as it was virtually 50 years ago.
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