LED LIGHTING

Calpak USA routinely assembles LED arrays and driver circuits on insulated metal substrate boards using aluminum or copper base layers that conduct heat away from LED junctions far more effectively than standard FR-4. These metal-core PCBs are essential for high-brightness LED applications where junction temperature directly affects lumen output, color consistency, and long-term reliability. At our Hawthorne, California facility, Calpak USA's process engineers develop reflow profiles that account for the significantly higher thermal mass of metal-core substrates, using extended soak zones and carefully controlled peak temperatures to achieve proper solder joint formation on LED pads without exceeding the maximum reflow specification of the dielectric isolation layer. We verify solder paste coverage on thermal pads using automated solder paste inspection before placement, preventing the voiding that would create thermal bottlenecks beneath high-power LED packages. Calpak USA also handles post-reflow heat sink attachment using thermal adhesives or mechanical fastening per the customer's design specification.

Calpak USA assembles LED driver circuits designed to meet UL 8750 safety requirements for LED equipment and DOE Energy Star efficacy standards that govern commercial lighting products sold in the United States. Driver assemblies commonly include power factor correction stages, constant-current regulators, dimming control interfaces, and EMI filtering circuits that must function together to deliver stable light output while meeting regulatory limits. At our Hawthorne, California facility, Calpak USA handles the mixed-technology assembly typical of LED drivers, combining surface-mount control ICs and small passives with through-hole electrolytic capacitors, transformers, and high-current inductors using a combination of reflow soldering and selective or wave soldering. Functional testing verifies output current regulation accuracy, dimming response across specified ranges, power factor measurements, and thermal shutdown protection thresholds. Calpak USA provides the manufacturing process documentation and test data that lighting OEMs need when submitting products for UL listing and Energy Star qualification.

High-brightness LED packages from manufacturers like Cree, Lumileds, and Osram typically feature large exposed thermal pads on their undersides that require precise solder paste deposition and controlled reflow to form a reliable thermal and electrical connection to the PCB. Calpak USA's SMT lines in Hawthorne, California use stencils with optimized aperture designs for these thermal pads, incorporating segmented patterns that promote solder paste release while controlling void percentages below customer-specified thresholds, typically less than 25 percent voiding per IPC-7095 guidelines. Our pick-and-place machines accommodate the optical centering requirements of LED packages where precise rotational alignment affects the beam pattern of the finished luminaire. For multi-color and tunable-white LED arrays, Calpak USA programs placement machines to maintain consistent orientation of each LED bin designation. Post-reflow X-ray inspection verifies thermal pad solder coverage and void content on representative samples, ensuring that thermal resistance from junction to board remains within the design specification for the target lumen maintenance rating.

Calpak USA assembles LED circuits on rigid FR-4 and metal-core substrates as well as flexible polyimide-based circuits used in architectural cove lighting, curved display backlights, automotive interior accents, and wearable illumination products. Flexible LED strips and panels present unique manufacturing challenges because the thin polyimide substrate requires gentle handling fixtures to prevent creasing during SMT processing, and reflow profiles must account for the lower thermal mass and different heat absorption characteristics compared to rigid boards. At our Hawthorne, California facility, Calpak USA uses vacuum-hold fixtures and custom carrier panels to stabilize flexible circuits through the solder paste printing, component placement, and reflow process steps. For rigid-flex LED designs that combine a rigid driver section with flexible LED array sections, Calpak USA manages the different assembly requirements of each region in a single coordinated production flow. Our ISO 9001 quality system ensures that flexible LED assemblies receive the same incoming inspection, process control, and functional test verification applied to all production at our facility.