To test the product further, a Pilot run normally follows the prototyping stage . In the Pilot run, a small quantity of units (for instance 25) are field trialled in a beta test. The Pilot run is also an opportunity to assess the manufacturability of the design, and the usability of the documentation.
PCB Assembly
A good electronics manufacturer tailors the reliability of his processes and assemblies to suit his customer?s requests. Certain customers market expensive industrial standard automation. Hence only the highest quality PCBs can handle complex circuitry for those.
The assemblies should be designed to be maintainable, repairable, durable and easily installed. The difference between a printed circuit board that is easy to work with and a PCB that confuse technicians can be as simple as proper labeling, connectors and sockets.
An example of high quality and standard characteristics:
1.IC Sockets used are Gas tight machine screw construction with 4 prong gold plated mating surfaces.
2.Data connectors have Gold
plated mating surfaces, tinned or chromated housings. 3.PCB Laminates are professionally
manufactured using Fibreglass FR4 stock, soldermask over bare copper (top &
bottom), PTH, tinned and silkscreen encoded with a full component identification
legend.
4.All connectors are polarised, with numbering clearly marked.
5.All interboard cabling is stranded. All light wire is tinned stranded.
6.Components subject to lowered MTBF due to external adverse factors (eg line drivers) are socketed.
7.All socketed components are identified, with orientation shown.
8.All parts used are first grade, new, manufacturers product meeting the full manufacturers specification.
9.All non-substitutable-at-repair components are clearly marked.
10.All parts & PCBs have been processed under anti-static conditions.
By combining the engineering and manufacturing operations, the manufacturers can be available to respond to the changing engineering requirements that arise from time to time in manufacturing, and ensure the highest quality final product.
The PCB Documentation
Designers should have a standard documentation package, which is supplied with all their design work. This package must be quite complete at a technical level, and contain all the information required to manufacture, modify or further develop the product.
The standard PCB documentation file that
the customer will receive with their job consists of:
1)Front Cover
Title, date, version number, customer details, project features
Schematic
(One or more pages)
3)ECO Sheet
Details of any circuit modifications. See ECO and version numbers.
4)Bill of material
The parts list.
5)Parts key
A glossary of the part number abbreviations, with package sizes, lead spacings, tolerance notes and preferred types
6)Front panel artwork
(If applicable to project).
7)Manufacturing notes
If project has proceeded from prototype to manufacture, this page will be included and will contain the notes relating to previous production runs - for instance problems encountered, methods of testing.
8)Drilling diagram
A diagram showing the positioning and size of every hole on the PCB.
9)Actual size PCB overlay
A diagram showing the positioning and identification of the PCB components. The plan is printed actual size to allow components to be placed against it to check for fit.
The printed circuit board and schematic diagram should also be supplied in CAD format on a diskette.