The following guidelines are provided for the purpose
of assisting Delta Circuits Inc. clients in the matching
of our production capabilities to their specific manufacturing
requirements. Although these guidelines represent the
full range of normal production capabilities, design parameters
as stated may be exceeded under controlled conditions
when indicated by client specifications. Please note that
all parameters stated can be achieved independently, but
may not in some instances be possible in combination.
Guidelines for Manufacturing and
Testing Specifications
In order to eliminate ambiguity in the specification of
manufacturing parameters, Delta Circuits Inc. advises
the procurement of boards manufactured to the intent of
an accepted international standard, i.e. (IPC-A-600, Rev.
E). In doing so, clients may be certain that manufacturing
and testing processes are performed to the requirements
of these specifications. Any non-standard or additional
specification must be stipulated on the purchase order.
Design Parameters to be Specified
LAMINATE:
State applicable specification within the following
preferred parameters:
- Minimum core thickness 0.005"
- Copper foil
1. outer layers:
maximum 4 oz.; minimum 1/2 oz.
2. inner layers:
maximum 4 oz. for power and ground layers; maximum 1 oz.
for signal layers; minimum 1/2 oz. for all layers
CONSTRUCTION:
Delta Circuits Inc. will employ all standard construction
procedures required to provide the best-balanced build
unless otherwise specified.
LIMITING DIMENSIONS:
- Maximum active board size is 20" x 22.5"
(including customer test patterns, where applicable)
- Maximum number of layers 18
- Minimum drilled hole 0.010"
- Minimum conductor width 0.005"
- Minimum spacing 0.005"
- Board aspect ratio 6:1
- BOARD THICKNESS:
Limiting tolerances on thickness
(maximums):
0.020" ±0.003"
0.031" ±0.003"
0.062" ±0.007"
0.093" ±0.008"
0.125" ±0.008"
BOW & TWIST:
Under normal manufacturing tolerances, the typical acceptable
deviation from flatness is 0.0075-0.015in./in. This
specification is subject to the uniform distribution
of circuitry across each layer.
FINISHES:
State finishes required, as follows:
Selective solder coating (hot-air leveling)
Gold over nickel over copper
Immersion white tin
Other finishes available upon request.
HOLE SIZES:
In the interest of reducing overall per-unit cost to
its customers, Delta Circuits Inc. recommends that clients
specify the fewest possible number of hole sizes per
each board design.
TOLERANCE OF OUTSIDE DIMENSIONS:
±0.005" minimum
DATUM POINT:
A common datum point must be specified for drilled holes,
profiled slots, and boundaries.
PROGRAMMING LAYER:
This layer must be clearly shown in the drawing and
will preferably be the layer with the smallest lands.
HOLE TOLERANCE:
Minimum hole diameter tolerances are as follows: Nominal
Diameter of Plated Through Hole After Plating Tolerances
0.035" or less ±0.002"
0.036" to 0.093" ±0.003"
above 0.094" ±0.005"
ANNULAR RING:
Minimum annular rings of lands on artwork should be
0.01" from finished hole size. Plated through holes
require lands on both sides of the board to ensure continuity
of circuitry. Through plating of the hole can be guaranteed
only when this requirement is reflected in the design
of the printed circuit board.
NON-FUNCTIONAL LANDS:
The inclusion of non-functional lands on inner layers
is not recommended.
ISOLATION CLEARANCES:
Isolation clearances on artwork must be a minimum of
0.012" from the drilled hole, i.e. the epoxy-glass
areas around holes in the ground/power plane.
ARTWORK DESIGNED ON GRID:
Artwork designed on grid should be indicated as such,
as drilling to grid location is preferred.
SOLDER MASK & LEGEND:
If required, colors for solder mask and legend must
be stated. Preferred colors:
- Solder Mask: Green-Blue-Red-Black-Clear
- Legend: White-Yellow-Black
CIRCUITRY:
Circuitry should be distributed uniformly across each
layer to minimize variations in plated thickness and
flatness on the finished board. In areas where low pattern
density or ground planes are present, cross-hatching
is often advisable.
CONDUCTOR
WIDTHS:
Finished conductor widths must be stated. Tolerances
depend on copper thickness.
ARTWORK:
The artwork nominal must be 0.002" greater than
the nominal finished board requirement.
DESIGN NOTES:
Assistance with design tolerances, complexity issues,
and board capabilities is available upon request.
Critical tolerances should be specified where acceptable.
Most tolerances are limited by the dimensional stability
of the available base materials.
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