BREADBOARD SOLDERING TECHNIQUES
FOR PROTOTYPE SURFACE MOUNT ASSEMBLIES
Surfboards are compatible with most standard soldering processes from hand soldering through automated industrial processes.
HAND SOLDERING: Use very fine point low wattage iron in the 10-40 Watt range. Fine flux core solder is available in diameters of 10 or 20 mils, and works well where small controlled volumes of solder are needed. You should practice making a variety of solder joints with different types of discrete components and I.C. s before starting to build actual circuit prototypes. You can ease eye strain by working under a magnifier. Use some means to keep the board in place while working, as you will need both hands to feed solder and operate the iron. You can use an adhesive to secure parts prior to soldering if desired. While not essential, this can make the process easier. See Adhesive Attachment for general information and suggestions.
SOLDER PASTE AND REFLOW: Use solder paste in syringe type applicator with tip and dispense small dots of paste at each joint location. Place surface mount device on paste and align. Be careful not to smear the paste off the pads as paste on non pad areas may form a ball which is not incorporated into the joint when later reflowed, and could cause shorts if not removed. Reflow of the assembly is accomplished with a hot plate or hot air type system commercially available for this purpose. It is possible to get creative and devise other heating methods if budgetary or availability issues require it. We have seen novel setups based on hot plates of all descriptions, heat lamps, and hot air guns. The important thing is to limit the upper temperature, and ramp up to it based on the recommendations of the solder paste supplier. Of course, if you have access to commercial processes these may expedite the operation significantly. If using conveyorized reflow ovens, it may be necessary to use a socket strip to keep SIP pins in alignment on models using them.
DIP / WAVE SOLDERING: In some cases it may be possible to dip or wave solder Surfboard assemblies. On models with SIP pins you can use the pins as a convenient way to hold the board by using a socket strip. Components must be attached to the board with an adhesive with this process. See adhesive attachment for more information. This process is somewhat limited and works best with discrete components. I.C.s and very small parts are prone to shorting if dip or wave approach angle is not correct. The method can provide a semi-production means to produce circuits such as networks and passive arrays with nothing more than a table top solder pot and some flux.
POST SOLDER CLEANING: To skip this step entirely use a NO CLEAN core or paste flux type. You may also use a WATER SOLUBLE flux that can give very good results and can be cleaned easily without special equipment. If using a rosin type flux you will have to use commercially available cleaners which may be solvent based.
