Wave Solder Pallets  
Conformal Selective Wave Solder Carriers - Exclusion Carriers

Also known as Exclusion Fixtures, Exclusion Pallets, Selective Jigs

The continuing rise of surface mount technology and compliant pin (press pin) connectors
has greatly reduced the number of PTH (pin through hole) connectors.

However pin through hole technology remains the preferred method of fixing older style
connectors and many magnetic components. This in turn has led to a style of mixed
technology boards with some or all of the following characteristics :-

 Conformal Selective or Exclusion Carriers
Open Aperture Wave Solder Carrier
Selective Wave Solder Carrier
Exclusion Fixtures
Adjustable Wave solder Fixture
Densely populated surface mount and pin through hole components

Densely populated.
Double sided.
Close pitched active SMT or thermally sensitive components which cannot be exposed to a wave.
A specification which bars or minimises the use of glue dot.
Pin through hole connectors - located close to previously reflowed surface mount components

PCB Hold Downs - Fixings
Pingu, Rockhopper & Emperor Fixings
Component Clamps

To wave solder these connections you need what we call a Conformal Selective Wave Solder Carrier (CSWSC)

This is a tooling pallet which has been Designed to :-
Tophat Plungers
Design Rules for Exclusion Fixtures

Enclose all or nearly all solder side SMT components.
Expose some or all pin through hole (PTH) components.
 Selectively allow solder to flow around the pins by creating the largest possible through apertures.
Mask thermally sensitive areas such as BGA lands.
Mask through holes, and if desired ground plane areas and even screws or rivets.
Direct the flow of solder by sculpting the solder side of the carrier to conform to the local board layout.
Sculpted Masking tp promote optimal flow
Gerber, Excellon and other data required
 
Advantages

Reduced production time
 Increased product quality
 Increased board density
 Reduced board bowing
 Increased fixture stability

 elimination of the Glue Dot/Stencil, mini wave, or hand soldering processes.
elimination of shorts and thermally damaged components.
More complex and thermally sensitive SMT devices can be populated on the solder side.
which reduces stress related joint failures,and improves backplane and chassis cut-out alignment.
reducing board clamping requirements when compared to open style fixtures.

Disadvantages

Higher fixture costs
 Longer Procurement

exclusion fixtures normally cost around 50-200% more than "picture frame" fixtures.
turnaround times are typically 3-5 days rather than the usual 1-3.

To find out if your pcb (pwb) is suitable for this process please go to CSWSC Design Rules