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Flex Circuit Tolerances & Mechanical Properties

Tolerances

Circuit Layer Design Guidelines
Attribute
Nominal
Detail
Minimum
 Preferred
Line Width - Outer Layers
A
0.0015"
.002"+
Line Width - Inner Layers
B
.001"
.002"+
Line to Line Space - Outer Layers
C
0.0015"
.002"+
Line to Line Space - Inner Layers
D
.001"
.002"+
PTH Diameter - Drilled
Ø
.001" min.
PTH to PTH Pitch - Center to Center
F
Ø+.0065"
Ø+.0075"+
PTH Pad Diameter - Outer Layer
G
Ø+.002"
Ø+.003"+
PTH Internal Land Diameter - Inner Layers
H
Ø+.002"
Ø+.003"+
PTH Clearance Diameter - Inner Layers
I
Ø+.004"
Ø+.005"+


Coverlayer Design Guidelines
Polyimide Coverlay
Photo Imageable Coverlay
Nominal
Tolerance
Nominal
Tolerance
Min.
Pref.
Min.
Pref.
Min.
Pref.
Min.
Pref.
Feature Size
0.008"
0.020"
± 0.001"
± 0.010"
0.004"
0.018"
± 0.001"
± 0.002"
Registration
-
-
± 0.001"
± 0.010"
-
-
± 0.003"
± 0.005"

If your design requirements exceed the capabilities stated above, please contact the factory to see if an alternative process or tooling are available.

Mechanical Properties

Optimum Sizes
Tech-Etch provides circuits up to 16" long. Multi-layer circuits up to 6 conductive layers are available. Consult factory for larger sizes.

Shielding
For designs requiring shielding, additional layers of copper can be added in solid or grid patterns. Conductive ink shield layers are also available.

Flexibility
Dynamic regions on a Flex Circuit should be identified on the print to allow for manufacturing features that will enhance dynamic performance. The following are general guidelines that apply to non-dynamic applications where bends are for installation only.
       Minimum Bend Radius
       Single Layer Circuit:  10x thickness
       Multi-Layer Circuit:    20x thickness

Temperature
Most often the adhesive used is the limiting factor for high temperature rating continuous service. Typical values are 105C (221F) for epoxy adhesive and 120C (248F) for acrylic adhesive. Both systems will withstand normal soldering practices after a moisture driving bake.