Secondary Source Bring up Cost Metrics and Net Present Value Calculation
Secondary source bring-up generates positive Net Present Value when unit cost savings and risk offsets exceed fixed tooling and qualification expenses.
SMT Tooling
Meaning
A set of specialized mechanical instruments and custom plates supports and guides circuit boards during the automated surface mount assembly process. This equipment class, known as SMT tooling, includes solder paste stencils, component feeder trays, and custom carrier plates used to hold double-sided boards.
Stencil Design
Laser-cut steel foils are engineered to control the exact volume of solder paste deposited onto the copper pads of the circuit board. SMT tooling of this type uses precise aperture sizes and foil thicknesses to prevent solder bridging or insufficient solder joints. The stencil must align perfectly with the fiducial marks on the raw board to avoid misaligned prints.
This calibration of the stencil prevents a large percentage of potential defects on the assembly line before the board ever reaches the oven.
Carrier Support
Double-sided boards or boards with overhanging edge connectors require custom pallets to hold them flat during component placement and reflow. These carriers protect components on the underside from being crushed or desoldered during the second pass through the oven. Using rigid support fixtures prevents the printed circuit board from flexing or warping under high thermal loads.
This stability during transit keeps delicate solder joints intact.
Feeder Configuration
Automated pick-and-place machines utilize mechanical or pneumatic feeders to present components to the vacuum nozzles. Each feeder must be matched to the tape-and-reel width of the component being mounted. This mechanical integration ensures a constant supply of parts to the placement head without jamming.
It allows the assembly line to achieve the high cycle speeds required for cost-effective manufacturing.