|
SOLDERING TECHNIQUES
|
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 10-25 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 are 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.
|
|
