FR4 Semiflex - cheaper than a cable harness?

FR4 Semiflex - cheaper than a cable harness?

FR4 Semiflex - cheaper than a cable harness?
Webinar May 06, 2014
07.05.2014
page 1 of 30
Speaker: Andreas Schilpp
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FR4 Semiflex - cheaper than a cable harness?
 Terms and definitions
 System comparision: cable harness versus FR4 Semiflex
 Design process
 Design rules, layer stack-up
 Production process
 „Cost- / performance-“ relations
 processing FR4 Semiflex boards
 Application examples
 Outlook
07.05.2014
page 2 of 30
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Terms and definitions 1
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semi is a latin Prefix meaning „half“ (Wikipedia)
Flexibility : if you try to find this in Wikipedia you will find yourself in „Stiffness“
(lat. flectere‚ bending) (Wikipedia)  not very precise and helpful 
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So in this context everything is flexible ???
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Definition: FR4Semiflex = bendable
Thin or partially thin with a special soldermask without flexible foils like PI
07.05.2014
page 3 of 30
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Terms and definitions 2
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Partial thickness reduction typically performed by depth routing
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Normally using a special routing bit (bevel, radius) (recommended!)
Sometimes also using seperating foils or release lacquer
pictures: Ruwel, WE
07.05.2014
page 4 of 30
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Terms and definitions 3
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Clarification regarding „Duraflex (Isola 2005): never produced in serie
Today Isola advertises „Semiflex“  special FR4 thin laminates
Influences on bendability are:
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thickness
Resin and glas quality
Mechanical design and routing
Copper quality
source: Isola, WE
07.05.2014
page 5 of 30
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Big influence: Prepreg construction
FR4 prepreg type 106
dielectric thickness
50 – 55 µm
FR4 prepreg type 1080
dielectric thickness
60 - 70 µm
FR4 prepreg type 2116
dielectric thickness
85 – 100 µm
FR4 prepreg type 7628
NOT suitable for
• microvias
• FR4 Semiflex
Source: Isola
07.05.2014
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System comparison: cable harness versus FR4 Semiflex
Heterogeneous system
07.05.2014
page 7 of 30
Homogeneous system
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System comparison: cable harness versus FR4 Semiflex
Heterogeneous system
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07.05.2014
Cheaper for very few contacts
Lot of solder and contact points
Detachable in case of connector
Very robust (pulling on the cables)
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Homogeneous system
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Less components, logistics easier
Saving area for connector footprint or
solder joints
The best wiring safety
Perfect testability
Better signal integrity
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System comparison: angled connector vs. FR4 Semiflex
07.05.2014
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Production process: FR4 Semiflex multilayer 8 layers
07.05.2014
page 10 of 30
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Production process: FR4 Semiflex multilayer 8 layers
07.05.2014
page 11 of 30
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Production process: FR4 Semiflex multilayer 8 layers
07.05.2014
page 12 of 30
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Production process: FR4 Semiflex multilayer 8 layers
07.05.2014
page 13 of 30
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Next up, we do a…
For an easy communication we use a logical structure for the naming of
the stack-up comparable to flex-rigid
What do you mean:
Which one is the correct nomenclature of a FR4 Semiflex multilayer with
- 8 layers, of which are
- 1 copper layer in the bending area on TOP and
- 1 copper layer in the bending area on Bottom?
07.05.2014
page 14 of 30
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Design process
Our vision of a
system house:
07.05.2014
page 15 of 30
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Design rules, layer stack-up
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WE Design rules always up-to-date on internet!
unfavourable:
copper free areas, small contour radii
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good:
bending area filled with copper, large contour radii
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Layer stack-up: ask for proposal from WE!
07.05.2014
page 16 of 30
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Design rules
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Regard bending direction
S-shape bending with 2 bending areas!
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Optimize bearing construction
07.05.2014
page 17 of 30
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Bending radii, bending angles, length of bending area
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Minimum bending radius R with bending area…
– 1-layer: standard 5mm (as a comparison: flex-rigid 1mm)
– 1-layer with special adapted WE stack-up: 4mm
– 2-layers: after consultation (strongly dependant from stack-up)
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Count of bending cycles: typically 10 x with minimum bending radius
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Lengt L of bending area
07.05.2014
page 18 of 30
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FR4 Semiflex: Pre-pending and fixation
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Well defined pre-bending prior to box installation!
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Assembly on
plastic housing:
07.05.2014
page 19 of 30
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Design: hints and tipps
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Linked chain – reduced milling expenditure
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07.05.2014
Single segments bended only some degrees!
Replace big 180° areas by 2 x 90° with rigid intermediate section
page 20 of 30
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Cost- / performance-“comparison: FR4 Semiflex vs. cable harness
Cost
Performance
07.05.2014
page 21 of 30
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Cost- / performance-“comparison: FR4 Semiflex vs. flex-rigid
Cost
Performance
07.05.2014
page 22 of 30
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Next up, we do a….
Where do you personally expect the biggest potential in
changing from a cable harness to FR4 Semiflex?
Multiple answers are possible!
07.05.2014
page 23 of 30
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Application expample
Measurement unit hydraulic drive
Old solution!
07.05.2014
page 24 of 30
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Application expample
Measurement unit hydraulic drive - NEW
Semiflex bare board…
07.05.2014
page 25 of 30
…assembled…
…built in
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Application expample
„TPC84“ Touchscreen control panel with Ethernet / TCP/IP connection
07.05.2014
page 26 of 30
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Application expample
Switchbox 12 x 13
Applications:
Groundwater exploration,
geotechnical investigation,
monitoring of dams and dikes,
environmental studies,
geological survey,
mineral prospecting,
archaeology,
detecting of cavities and buried
objects,
underwater, marine, borehole
and cross-hole measurements.
07.05.2014
page 27 of 30
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Application expample
Switchbox 12 x 13
07.05.2014
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Application expample
Switchbox 12 x 13
07.05.2014
page 29 of 30
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Outlook
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In development: bending area with 3 layers
„Power“ Semiflex:
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07.05.2014
combination with welded WIRELAID wires
page 30 of 30
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