Selective soldering is emerging as a necessary technology for companies that produce circuit boards with a mix of SMT and through-hole components. In the past, the choices for soldering through-hole components have been limited to hand soldering, masked wave soldering, and single/multi tube nozzles for dedicated selective soldering equipment.

The most typical process is hand soldering which often produces upwards of 1000 defects per million opportunities (DPMO). The defects range from insufficient fill due to varying solder dwell times to cold solder joints and missed joints. While labor intensive and hampered by defects, hand soldering is the most widely accepted method for soldering the through hole leads in heavily populated double-sided circuit board assembly.

The EMPF has the Jade Selective Solder System from Pillarhouse. The Jade is a flexible, low cost, single point soldering system with a large capability. This particular system is designed for the smaller batch where high flexibility is required. The Jade incorporates a board support system that can hold a PCB of up to 18" x 20". The unit has an easy to use, cost saving, hand load operation which provides the user great flexibility for quick changes in small batch processing. While the loading is done by hand, the soldering process is fully automated. A built-in solder height measurement feature helps ensure the best results. The soldering process is enhanced by the use of an inert hot nitrogen curtain, which has the effect of localized pre heat thus avoiding thermal shock, and helps to prevent oxidation.

The Jade selective soldering system, with topside board pre-heating, uses four individually controlled, fast-response, medium-wavelength infrared lamps. The lamps can be individually turned on and off and the lamps’ power controlled. An optional thermocouple placed on the board can also provide closed-loop control. The program can heat the board under ramp-rate control and maintain the target temperature during soak. The ramp-rate control determines the maximum allowable rate at which the board will heat from ambient to the target temperature. When using the closed-loop system, users can choose to use a cooling timer or a temperature setting from the board to unlock the lid and handle the board. Users also can choose between closed or open-loop operations.

A key feature to this system is the very accurate drop-jet fluxing system which has the ability to operate either in a completely separate fluxing program or as part of a simultaneous flux/soldering operation. A low maintenance solder bath and pump mechanism has been developed by Pillarhouse that moves in three axes while not limiting access to the PCB. Solder is applied using proven technology through their patented nozzle design or other custom designed nozzles.

The Jade series are PC controlled, allowing machine operation through PillarComm, a Windows based “point and click” interface. Options available include a fiducial correction system, an automatic solder wire feed and level detect system, selective pre-heat, solder wave height measurement system, and a separate lead-free solder
pot assembly.

For more information related to this article, or to schedule a demonstration of the Jade series selective solder system located at the EMPF, contact Ken Friedman, 610.362.1200 extension 279 or via email at kfriedman@aciusa.org.