BS 9761:1988 download.Sectional specification for capability approval of manufacturers of multilayer rigid printed wiring boards of assessed quality with plated through holes.
1.1 Scope
BS 9761 specifies requirements for the capability approval of manufacturers of multilayer rigid printed wiring boards with plated through holes (PTHs). It also includes requirements for quality conformance inspection.
The standard indudes tests, selected from those described in BS 9760, for use in capability approval and in conjunction with detail specifications.
The standard also includes guidance on the preparation of customer detail specifications.
NOTE. There are no requirements for, rivets, turrets, etc. The aeument and release of such features should be by separate local agreement between the manufacturer and the customer.
12 Related documents
BS 9761 makes reference to the following publications.
BS 2011 Basic environmental testing procedures Part 2.lCa. Test Ca. Damp heat, steady state
BS 4584 Metal-clad base materials for printed wiring boards
Part 2 Epoxide woven glass fabric copper-clad laminated sheet, general purpose grade:
EP-GC-Cu-2
Part 3 Epoxide woven glass fabric, copper-clad laminated sheet, flame retardant grade:
E P-GC-Cu-3
Part 9 Flexible copper-blad polyester (PETP) film: PETP-F-Cu-9
Part 10 Flexible copper-clad polyimide film:
P1-F-Cu-i 0
BS 6096 Marking inks and solder resist coating materials for printed circuits
BS 9000 General requirements for a system for electronic components of assessed quality Part 1 Specification of basic rules and procedures
BS 9760 Specification for printed circuits of assessed quality: generic data and methods of test:
capability approval procedure and rules BS 9762 Sectional specification for capability approval
of manufacturers of double-sided rigid printed wiring boards of assessed quality with plated through holes
BS 9763 Sectional specification for capability approval of manufacturers of single- or double-sided printed wiring boards of assessed quality without plated through holes
2.2.4 Diameter of PTH
The diameter of the PTH shall be within the limits listed
in appendix H.
NOTE. Smaller diameter PTHs may be used to demonstrate an dditiori& capabihty.
2.2.5 Number of l.yen
The minimum number of layers shall be eight arranged as shown for the CTP in appendix N.
NOTE. Capability for more than eight layers may be demonstrated using the pattern construction for the CTP shown in appendix N. The number of layers for approval should be based on the maximum experienced In production.
2.2.6 Finishes
2.2.6.1 Different finishes. All different finishes (organic and inorganic) whether for surface and/or edge contacts shall be assessed separately (see 2.3.3.3).
NOTE. With the agreement of the National Supervising Inspectorate (NSI). approval to one specification in the BS 9760 series of sectional specifications may be transferred for use in establishing approval to another specification in the series, in lieu of further testing.
22.62 Edge connector finish thickness. The thidcness of finishes required for the minimum level of capability shall be as given in table 2.
NOTE. Thinner coatings may be used to demonstrate additional capability.
22.7 Additional features
2.2.7.1 Surface bonded heat sinks or other metallic layers. The test specimens used shall be either boards with the test pattern shown in appendix H of BS 9762: 1988 or suitable production boards, if an equivalent level of assessment is achieved.
Each type of heat sink and its surface finish (e.g. nickel plated copper, anodized aluminium) shall be assessed separately, in accordance with table 2.
NOTE 1. Aspects such as shape and the method used to manufacture the heat sink are not assessed. The assessment is restricted to the mechanical end electrical integrity of the bonding and to any degradation of the printed wiring board. Thermal design aspects of the heat sink are not assessed.
NOTE 2. Test results establishing approval I or heat sinks on double-sided boards can normally be used to establish approval for multilayer boards.
2.2.7.2 Landless or landed PTHs. These PTHs shall be assessed on specimen H without surface pads as described in 1.2.3.8 of BS 9760: 1977 using the relevant tests of table 2.
22.7.3 Other features. Suitable specimens shall be provided for other features as specified in 2.3.3 of
BS9760:1977.
2.3 Capability CTP allocation
2.3.1 Programme of capability assessment The programme of capability assessment shall comply with 2.3 of BS 9760: 1977.
2.3.2 Standard patterns
The standard patterns shown in appendices A to K and appendix M shall be used for demonstrating standard capability. Hole dimensions shall be as specified in appendix L.
The quantities of patterns to be supplied for capability assessment shall be as follows:
(a) for single size CTP: eight boards = eight CTPs (four separate production lots);
(b) for double size CTP: four boards = eight CTPs (four separate production lots);
(c) for quadruple size CTP: two boards = eight CTPs (two separate production lots);
(d) for sizes other than those given in (a) to (c), the CTP layout shall be by agreement with the NSI; a minimum of eight CTPs and at least two complete boards shall be provided.
Each of the boards in (a) to (d) shall have the same finish.
2.3.3 Test specimen allocation
2.3.3.1 General. The specimens for each test shall be selected from as many complete boards and CTPs as possible.
Tests for items 1 to 9 and 32 to 34 of table 2 shall be carried out on the complete boards before any subdivision into CTPs. The tests for items 10 and 34 shall be made on the complete CTP before subdivision into specimens. A total of six CTPs shall be allocated for test items 11 to 26 of table 2 as shown in table 1. The lots from each CTP shall be kept separate and identified. The capability approval specimens shall be tested in accordance with the schedule given in table 2. Where the performance requirements of table 2 are not applicable, the manufacturer shall specify the test limits, as specified in 2.3.1 of
BS9760:1977.
The remaining two CTPs shall be used for two purposes as follows:
(a) as reserve specimens in case of accidental damage before testing (in any subdivision, note the requirement for specimens for item 27 of table 2);
(b) to provide specimens for the thermal shod test (item 27 of table 2).
32 Certified test records
Certified test records shall be prepared giving attributes information specified in subgroups A5. B8 and C6 in table 3.