GREEN ENERGY

Calpak USA manufactures power electronics assemblies for solar microinverters, string inverters, maximum power point tracking controllers, and lithium-ion battery management systems used in residential, commercial, and grid-scale energy storage. At our Hawthorne, California facility, we handle the unique requirements of power conversion circuits including high-current bus bar soldering, IGBT and MOSFET mounting with controlled thermal interface material application, and precision placement of current sense resistors and isolation transformers. Calpak USA's process engineers develop reflow profiles optimized for mixed assemblies that combine high-thermal-mass power components with sensitive gate driver ICs and microcontrollers on the same board. Our functional test capabilities verify critical parameters including conversion efficiency, over-current protection thresholds, and communication bus integrity for BMS cell balancing circuits. This experience spans designs operating from 12-volt battery systems through 1000-volt DC string inverter architectures.

Calpak USA assembles power electronics boards carrying sustained currents from tens of amps through designs rated above 200 amps per phase, which are common in EV charging stations, grid-tied inverters, and commercial energy storage systems. Our Hawthorne, California facility handles wide bus bar attachment using selective soldering and mechanical fastening, press-fit pin insertion for high-current connectors, and precision placement of current-sensing shunt resistors where milliohm accuracy affects system protection and metering functions. Calpak USA's selective soldering equipment accommodates through-hole power components that cannot withstand reflow temperatures, allowing mixed-technology boards to be processed efficiently without manual soldering on critical power path joints. For assemblies requiring wire bonding or direct copper bonding to ceramic substrates in hybrid power module configurations, Calpak USA coordinates with specialized subcontractors while maintaining full traceability. Our ISO 9001 certified quality system ensures that high-current joints receive the inspection rigor these safety-critical applications demand.

Calpak USA regularly assembles boards fabricated with heavy copper layers ranging from three ounces to ten ounces per square foot, as well as metal-core PCBs using aluminum or copper base substrates common in power electronics and high-brightness LED driver circuits for solar-powered lighting systems. These substrates present manufacturing challenges because their elevated thermal mass requires modified reflow profiles with extended soak zones and higher peak temperatures to achieve proper solder joint formation. At our Hawthorne, California facility, process engineers use multi-point thermocouple profiling to validate that all solder joints reach liquidus temperature without exceeding component maximum ratings. For insulated metal substrate boards, Calpak USA controls component placement pressure to avoid damaging the dielectric isolation layer between the copper circuit and aluminum base. Our experience with these specialty substrates allows renewable energy OEMs to leverage improved thermal conductivity in power converter and motor drive designs without concerns about manufacturing yield loss or solder quality degradation.

Calpak USA's Hawthorne, California facility operates fully qualified lead-free assembly lines using SAC305 and SAC405 solder alloys that comply with the EU Restriction of Hazardous Substances Directive and equivalent regulations in other jurisdictions. Lead-free soldering requires tighter process control because SAC alloys have narrower process windows, higher liquidus temperatures, and different wetting characteristics compared to traditional tin-lead solders. Calpak USA's reflow ovens maintain zone-by-zone temperature accuracy within plus or minus two degrees Celsius, and our engineers validate each new product's reflow profile against IPC J-STD-001 and IPC-7530 guidelines for lead-free processing. Wave and selective soldering stations operate with dedicated lead-free solder pots, and our material handling procedures prevent cross-contamination between leaded and lead-free production areas. For renewable energy products requiring UL, CSA, or TUV certification, Calpak USA provides the process documentation and material declarations that certification bodies require to verify RoHS compliance throughout the bill of materials.