Soldering_TrainingProgram

A proper soldering training program shall accomplish the following: (1) Identify the criteria for qualification (and/or certification), and (2)Document the methods and procedures proposed to fulfill the training requirements Documentation may include: Qualifications of instructors, Procedures for training, including who will be trained and for what purpose, (e.g., operator, inspector), Lesson plan(s)/student standards, Hours of instruction, Procedures for certification and recertification, Procedures for recording training, re-certification, method of identifying/recalling trained personnel, and certification criteria. Use visual standards consisting of satisfactory work samples or visual aids that clearly illustrate the quality characteristics of soldered connections. Standards of unacceptable conditions may also be used for clarification or comparison.

NASA Student Workbook for NASA standard NASA-STD-8739.3 summarizes many procedures for soldering. Among them "Wire Stripping", "Tinning: Solder Pot", "Tinning: Solder Iron", "Hook Terminal", "Pierced Terminal", "Turret Terminal", "Bifurcated Terminal", "Connector Pin", "Terminal Swaging", "Axial Lead", "Vertical Mount", "Interfacial Connection", "Lapped Terminations", "Continuous Run Wrap - Bifurcated", "Continuous Run Wrap - Turret"  and "High-Voltage Solder Joints" are summarized in this section.

 

Wire Stripping (Procedure 1)

Step 1: WIRE PREPARATION
Prepare a wire by cutting an appropriate length using side cutters.



Step 2: USING A THERMAL WIRE STRIPPER




Step 2a: WIRE STOP SETTING
Adjust the wire stop to the desired strip dimension. Always measure the insulation strip dimension from the outside edge of the electrode tips.



Step 2b: TEMPERATURE SETTING
Turn the power switch ON. Set the knob to the correct temperature for the type of insulation of the wire.


Step 2c: THERMAL WIRE STRIPPING
Hold the footswitch down to allow the electrodes to reach the operating temperature. Keep the switch depressed.

Holding the wire in one hand and the thermal stripper in the other hand, insert the wire until the cut end contacts the wire stop.

CLOSE the electrodes on the wire to melt the insulation. Now OPEN the electrodes and rotate them about 30°, and again CLOSE the electrodes to melt another portion of the wire. Repeat the CLOSE to melt, OPEN to rotate operation until a complete ring has been melted around the insulation on the wire.

Remove the wire from the stripper. Release the footswitch. Place the thermal strippers where the electrodes will not cause any damage while they are cooling.

Step 2d: REMOVING THE INSULATION
Holding the wire in one hand, grasp the separated portion of the insulation with the thumb and forefinger of the other hand. Remove this portion with a smooth, even motion in the direction of the lay of the wire. Clean the stripped end with an approved solvent, being careful not to disturb the lay of the wire.

If disturbed, the lay of wire strands shall be restored as nearly as possible to the original lay.

Step 2e: INSPECTION
Inspect in accordance with STEP 4.

Step 3: MECHANICAL WIRE STRIPPING
With the jaws open, place the wire in the appropriate die corresponding to the wire size being stripped.

Squeeze the handles to partially cut and separate the insulation only a short distance. Slightly release the pressure on the handles.

Remove the wire, close the strippers, and set the strippers down. Mechanical strippers must not be operator adjustable, must be in calibration, and must not damage the wire or unstripped insulation.



Step 3a: REMOVE THE INSULATION PER STEP 2d
If disturbed, the lay of wire strands shall be restored as nearly as possible to the original lay.


Step 4: INSPECTION
Inspect under 4X to 10X magnification.

Conductors and parts rejections include: nicks, cuts, and crushing or charring of insulation (slight discoloration from thermal stripping is acceptable). After insulation removal, the conductor shall not be: cut, nicked, stretched, or scraped leads or wires exposing base metal (except smooth impression marks resulting from bending tool holding forces).

Tinning: Solder Iron (Procedure 2B)

Step 1: POSITION THE WIRE
Place the stripped wire in a vise or spring to hold it in a vertical position. Clean the wire with a soft brush, using the approved solvent and a shopwipe.

Step 2: PREPARE THE SOLDER
Prepare the solder by cutting the end (to expose the flux in the core) and clean with an approved solvent.


Step 3: PREPARE THE IRON
Prepare the iron by wiping the solder from the tip with a shopwipe.

Step 4: CLEAN THE IRON TIP
Lightly wipe the tip of the iron on the moist sponge to remove the oxides.

Step 5: TIN THE WIRE
Place the soldering iron tip against the wire near the cut end. Add solder at the junction of the tip and the wire, forming a thermal (solder) bridge that will transfer the heat from the iron to the wire. Simultaneously move the iron up the wire, adding solder to the wire until the tinning has reached no closer than 0.5 mm (0.020 in.) to insulation.

Step 6: REMOVE THE IRON
Slide the iron down and off the end of the wire, adding solder only as needed.

Step 7: TIN THE IRON
Tin the iron tip, while the connection is cooling at room temperature. A small amount of solder should remain on the tip. Return the iron to the holder.

Step 8: CLEAN THE WIRE
Clean the flux from the tinned portion of the wire with an acid brush, using the approved solvent and a shopwipe.

Step 9: INSPECTION
Inspect the tinned wire under 4X to 10X magnification. Conductor tinning personnel shall
ensure that tinned surfaces exhibit 100% coverage. Wire strands shall be distinguishable. The appearance of the solder joint surface shall be smooth, nonporous, undisturbed, and shall have a finish that may vary from satin to bright depending on the type of solder used. Flow (wicking) of solder along the conductor is permitted. Solder shall not make presence of the individual wire strands indistinguishable.

Hook Terminal (Procedure 3)

Step 1: PREPARE THE CONNECTION
1a. Prepare a stranded wire in accordance with Procedures 1 and 2A/2B on Stripping and Tinning, respectively.

1b. Insert a terminal into a phenolic block (or equivalent). Secure the block in a vise.


1c. Clean the terminal with an acid brush, using the approved solvent and a shopwipe.

1d. If necessary, add flux on the portion of the terminal to be tinned.

1e. Clean the iron by wiping the tip with a dry shopwipe. Lightly wipe the tip on a moist sponge to remove the oxides.

1f. Tin the terminal by positioning the iron as shown and adding solder to form a solder bridge. Add solder as necessary.
CAUTION: Allow time for the terminal to cool before proceeding.

1g. Place the solder wick on the solder. Place the solder iron on top of the wick to remove the solder from the terminal.

1h. Clean the tinned terminal with an acid brush, using the approved solvent and a shopwipe. Inspect for a uniform layer of solder.

1i. Grasp the end of the stripped and tinned wire with a pair of pliers. Place the wire up against the bottom of the hook.

1j. With a lifting motion on both sides, wrap the wire tightly around the terminal, being aware of the proper insulation clearance. The insulation shall not be embedded in the solder joint, and shall be less than two wire diameters, including insulation.

1k. Slide the wire off the terminal. Using wire cutters, flush cut the bent wire so that it will only make contact with the terminal for 180° minimum (1/2 turn) to 270° maximum (3/4 turn). 26 AWG and smaller wire shall be 180° minimum (1/2 turn) but less than one full turn 360° maximum (1 turn).

1l. Hold the cut wire against the terminal to check the wrap dimension. The wire shall contact the terminal for the full turn for which it is cut. Recut the end of the wire as necessary.

The insulation shall not be imbedded in the solder joint, and shall be less than 2 wire diameters, including insulation. Protrusion of the conductor ends shall be controlled to avoid damage to the insulation sleeving.

Step 2: POSITION THE WIRE
Attach the wire from the terminal to the spring, which will hold it during the soldering. Adjust the wire for the proper tension, centering, and position.

Step 3: CLEAN THE CONNECTION
Clean the connection with a soft brush using the approved solvent and a shopwipe. Do not disturb the position of the wire.

Step 4: CUT THE SOLDER
Cut the end of the solder to expose the flux in the core of the solder. Wipe the solder with a shopwipe and solvent to remove any contaminants.

Step 5: CLEAN THE SOLDERING IRON
Prepare the iron by wiping the tip with a shopwipe.

Lightly wipe the tip on a moist sponge to remove the oxides.


Step 6: POSITION THE IRON
Place the clean soldering iron tip against the bottom of the wire so as to contact both the wire and the terminal at the same time.

Step 7: APPLY SOLDER
Apply a small amount of solder to the junction where the wire, terminal, and tip meet to make a solder bridge. Now touch the solder to the end of the cut wire to cover the exposed copper. Add solder as needed to complete the soldered connection. Remove the solder; remove the iron.

Step 8: TIN THE IRON
Tin the iron tip, while the connection is cooling at room temperature. A small amount of solder should remain on the tip. Return the iron to the holder.

Step 9: CLEAN THE CONNECTION
Clean the flux from the soldered connection with an acid brush, using the approved solvent and shopwipe.

When more than one conductor is connected to the terminal, the direction of the bend of each additional conductor shall alternate.

Step 10: INSPECT THE CONNECTION
Inspect the solder joint under 4X to 10X magnification to the specified requirements. Free of flux residue and other contaminants. The surface shall be smooth and nonporous. It shall be undisturbed and have a finish that may vary from satin to bright. The solder shall wet all elements of the connection. The solder shall fillet between connection elements over the complete periphery of the connection. The lead contour shall be visible. Proper insulation clearance.

For detailed inspection criteria refer to NASA-STD-8739.3 and Appendix A of 8739.3.

Pierced Terminal (Procedure 4)

Step 1: PREPARE THE CONNECTION
1a. Prepare a stranded wire in accordance with Procedures 1 and 2A/2B on Stripping and Tinning, respectively.

1b. Insert a terminal into a phenolic block (or equivalent). Secure the block in a vise.

1c. Clean the terminal with an acid brush, using the approved solvent and a shopwipe.

1d. If necessary, add flux on the portion of the terminal to be tinned.

1e. Clean the iron by wiping the tip with a dry shopwipe. Lightly wipe the tip on a moist sponge to remove the oxides.

1f. Tin the terminal by positioning the iron as shown and add solder to form a thermal (solder) bridge. Add solder as necessary.
CAUTION: Allow time for the terminal to cool before proceeding.

1g. Place the solder wick on the solder. Place the solder iron on top of the wick in order to clean the solder from the terminal.

1h. Clean the terminal with an acid brush, using the approved solvent and a shopwipe. Inspect for a uniform layer of solder.

1i. To bend the wire 180° (1/2 turn) for the END ENTRY, place the wire through the eyelet and grasp the end of the stripped and tinned wire with a pair of pliers. While holding the end of the wire with the pliers, bend the insulated portion of the wire up with your fingers. Now hold the insulated portion firmly with your fingers, and bend the wire end up with the pliers.

The insulation shall not be imbedded in the solder joint, and shall be less than 2 wire diameters, including insulation.

1j. Remove the wire from the terminal. Using wire cutters, cut the bent wire so that it will only make contact with the terminal for 180° (1/2 turn).

[ALTERNATE BEND 1]
To bend the wire 90° (1/4 turn) for END ENTRY, place the wire through the eyelet and grasp the end of the stripped and tinned wire with a pair of pliers. Bend the insulated portion of the wire up tightly against the terminal with your fingers, while holding the wire (with the pliers) in place. Be aware of the proper insulation clearance.


[ALTERNATE BEND 2]
To bend the wire 90° (1/4 turn) for SIDE ENTRY, place the wire through the terminal and grasp the end of the stripped and tinned wire with a pair of pliers. While holding the insulated portion with the fingers, bend the wire held with the pliers tightly against the terminal to a right angle (1/4 turn), being aware of the insulation clearance.

[ALTERNATE BEND 3]
To bend the wire 90 + 90° (Z-bend) for the END ENTRY, place the wire through the terminal and grasp the end of the stripped and tinned wire with a pair of pliers. While holding the wire in place (with the pliers), bend the insulated wire with your fingers to a right angle (1/4 turn). Cut the end of the wire and bend opposite the direction of the first bend. Be aware of the insulation clearance.

1k. Hold the cut wire against the terminal to check the cut. The wire shall contact the terminal for the full turn for which it is cut. Re-cut the end of the wire as necessary.

Step 2. POSITION THE WIRE
Attach the wire from the terminal to the spring, which will hold it during the soldering. Adjust the wire for the proper tension, centering, and position.

Step 3. CLEAN THE CONNECTION
Clean the connection with a soft brush, using the approved solvent and a shopwipe. Do not disturb the position of the wire.

Step 4. CUT THE SOLDER
Cut the end of the solder to expose the flux in the core of the solder. Wipe the solder with a shopwipe and solvent to remove any contaminants.

Step 5. CLEAN THE SOLDERING IRON
Prepare the iron by wiping the tip with a dry shopwipe. Lightly wipe the tip on a slightly moist sponge to remove the oxides.

Step 6. POSITION THE IRON
Place the clean soldering iron tip against the terminal so as to contact both the wire and the terminal at the same time.

Step 7: APPLY SOLDER
Apply a small amount of solder to the junction where the wire, terminal, and iron meet in order to form a thermal (solder) bridge. Now touch the solder to the end of the cut wire to cover the exposed copper. Add solder as needed to complete the soldered connection. Remove the solder; remove the iron.

Step 8. TIN THE IRON
Tin the iron tip while the connection is cooling at room temperature. A small amount of solder should remain on the tip. Return the iron to the holder.

Step 9. CLEAN THE CONNECTION
Clean the flux from the soldered connection with an acid brush, using the approved solvent and a shopwipe.

Step 10. INSPECT THE CONNECTION
Inspect the solder joint under 4X to 10X magnification to the specified requirements.

Free of flux residue and other contaminants. The surface shall be smooth and nonporous. It shall be undisturbed and have a finish that may vary from satin too bright. The solder shall wet all elements of the connection. The solder shall fillet between connection elements over the complete periphery of the connection. The lead contour shall be visible. Proper insulation clearance. 

Turret Terminal (Procedure 5)

Step 1: PREPARE THE CONNECTION
1a. Prepare a stranded wire in accordance with Procedures 1 and 2A/2B on Stripping and Tinning, respectively.

1b. Insert a terminal into a phenolic block (or equivalent). Secure the block in a vise.

1c. Clean the terminal with an acid brush, using the approved solvent and a shopwipe.

1d. If necessary, add flux on the portion of the terminal to be tinned.

1e. Clean the iron by wiping the tip with a dry shopwipe. Lightly wipe the tip on a moist sponge to remove the oxides.

1f.  Tin the terminal by positioning the iron as shown and adding solder to form a solder bridge. Add solder as necessary.
CAUTION: Allow time for the terminal to cool before proceeding.

1g. Place the solder wick on the solder. Place the solder iron on top of the wick to remove the solder from the terminal. Inspect for a uniform layer of solder.

1h. Clean the tinned terminal with an acid brush, using the approved solvent and a shopwipe.

1i. To bend the wire around the terminal, grasp the end of a stripped and tinned wire with a pair of pliers. Place the wire on the base of the turret. Holding the wire in place with your fingers, move the pliers to wrap the wire tightly around the terminal, being aware of the proper insulation clearance.

1j. Remove the wire from the terminal. Using wire cutters, flush cut the bent wire so that it will only make contact with the terminal from 180° minimum (1/2 turn) to 270° maximum (3/4 turn). 26 AWG and smaller wire shall be 180° minimum (1/2 turn) but less than one full turn 360° maximum.

1k. Hold the cut wire against the terminal to check the wrap dimension. The wire shall contact the terminal for the full turn for which it is cut. 180° (1/2 TURN) TO 270° (3/4 TURN) Recut the end of the wire as necessary.

The insulation shall not be imbedded in the solder joint, and shall be less than 2 wire diameters, including insulation.


Step 2: POSITION THE WIRE
Attach the wire from the terminal to the spring to hold it during the soldering. The wire is mounted in the bottom guide slot and shall stay in contact with the base. Adjust the wire for the proper tension, centering, and position.

Step3. CLEAN THE CONNECTION
Clean the connection with a soft brush, using the approved solvent and shopewipe. Do not disturb the position of the wire.

Step 4. CUT THE SOLDER
Cut the end of the solder to expose the flux in the core of the solder. Wipe the solder with a shopwipe and solvent to remove any contaminants.

Step 5. CLEAN THE SOLDERING IRON
Prepare the iron by wiping the tip with a dry shopwipe.

Lightly wipe the tip on a slightly moist sponge to remove the oxides.

Step 6. POSITION THE IRON
Place the clean soldering iron tip against the turret base so as to contact both the wire and the terminal at the same time.

Step 7. APPLY SOLDER
Apply a small amount of solder to the junction where the wire, terminal, and iron meet to form a thermal (solder) bridge. Now touch the solder to the end of the cut wire to cover the exposed copper. Add solder as needed to complete the soldered connection. Remove the solder; remove the iron.

Step 8. TIN THE IRON
Tin the iron tip while the connection is cooling at room temperature. A small amount of solder should remain on the tip. Return the iron to the holder.

Step 9. CLEAN THE CONNECTION
Clean the flux from the soldered connection with an acid brush, using the approved solvent and a shopwipe.

Step10. INSPECT THE CONNECTION
Inspect the solder joint under 4X to 10X magnification to the specified requirements.

Conductor bend shall be 1/2 (180°) to 3/4 (270°) turn for conductors larger than AWG 26. Conductor bend shall be wrapped more than 1/2 (180°) but less than 360° for conductors AWG 26 and smaller. All conductors shall be confined to guide slots. Conductors shall be maintained in contact with the post for the full curvature of the wrap and the conductor ends shall not extend beyond the base of the terminal. More than one conductor may be installed in a single slot of sufficient width, provided each conductor is wrapped on the terminal post and not on another conductor. Free of flux residue and other contaminants. The surface shall be smooth and nonporous. It shall be undisturbed and have a finish that may vary from satin too bright. The solder shall wet all elements of the connection. The solder shall fillet between connection elements over the complete periphery of the connection. The lead contour shall be visible. Proper insulation clearance.

Bifurcated Terminal (Procedure 6)

Step 1: PREPARE THE CONNECTION
1a. Prepare a stranded wire in accordance with Procedures 1 and 2A/2B on Stripping and Tinning, respectively.

1b. Insert a terminal into a phenolic block (or equivalent). Secure the block in a vise.

1c. Clean the terminal with an acid brush, using the approved solvent and a shopwipe.

1d. If necessary, add flux on the portion of the terminal to be tinned.

1e. Clean the iron by wiping the tip with a dry shopwipe. Lightly wipe the tip on a moist sponge to remove the oxides.

1f. Tin the terminal by positioning the iron as shown and adding solder to form a thermal (solder) bridge. Add solder as necessary.
CAUTION: Allow time for the terminal to cool before proceeding.

1g. Place the solder wick on the solder. Place the solder on top of the wick in order to clean the solder from the terminal.

1h. Clean the terminal with an acid brush, using an approved solvent and a shopwipe. Inspect for a uniform layer of solder.

1i. For side entry, place the end of the stripped and tinned wire into the slot between the posts. Gently hold the wire with wire cutters at the desired length to cut off the wire. The insulation shall not be imbedded in the solder joint, and shall be less than 2 wire diameters, including insulation.

1j. Slide the wire out of the posts. Using wire cutters, now flush cut the wire.

1k. Hold the cut wire against the terminal to check the wrap connection. The wire shall enter the mounting slot perpendicular to the posts, be in contact with the terminal surface, and not extend beyond the diameter of the base. Recut the end of the wire as necessary.

Step 2. POSITION THE WIRE
Attach the wire from the terminal to the spring, which will hold it during the soldering. Adjust the wire for the proper tension, centering, and position.

Step 3. CLEAN THE CONNECTION
Clean the connection using a soft brush, using the approved solvent and a shopewipe. Do not disturb the position of the wire.

Step 4. CUT THE SOLDER
Cut the end of the solder to expose the flux in the core of the solder. Wipe the solder with the shopwipe and solvent to remove any contaminants.

Step 5. CLEAN THE SOLDERING IRON
Prepare the iron by wiping the tip with a dry shopwipe. Lightly wipe the tip on a moist sponge to remove the oxides.

Step 6. POSITION THE IRON
Place the clean soldering iron tip on the base of the terminal so as to contact both the wire and the terminal at the same time.

Step 7: APPLY SOLDER
Apply a small amount of solder to the junction where the wire, terminal, and tip meet to make a solder bridge. Now touch the solder to the end of the cut wire to cover the exposed copper. Add solder as needed to complete the soldered connection. Remove the solder; remove the iron.

STEP 8. TIN THE IRON
Tin the iron tip while the connection is cooling at room temperature. A small amount of solder should remain on the tip. Return the iron to the holder.

Step 9. CLEAN THE CONNECTION
Clean the flux from the soldered connection with an acid brush, using the approved solvent and a
shopwipe.

Step 10. INSPECT THE CONNECTION
Inspect the solder joint under 4X to 10X magnification to the specified requirements.  Side route conductors shall enter the mounting slot perpendicular to the posts. A conductor may lay straight through a terminal slot provided the conductor  surface remains in contact with the terminal surface. Conductor bend shall be 1/4 (90°) to 1/2.

More than one conductor may be installed on a single terminal post provided each conductor is wrapped on the terminal post and not on another conductor, and the direction of the bend shall alternate. Conductors shall not extend beyond the diameter of the base except where physical clearance will not adversely affect environmental or electrical characteristics. Free of flux residue and other contaminants. The surface shall be smooth and nonporous. It shall be undisturbed and have a finish that may vary from satin to bright. The solder shall wet all elements of the connection. The solder shall fillet between connection elements over the complete periphery of the connection.The lead contour shall be visible. Proper insulation clearance.

For detailed inspection criteria refer to NASA-STD-8739.3, Paragraph 13.6 and Appendix A.

Note: Alternate methods of mounting the bifurcated terminal:

Connector Pin (Procedure 7)

Step 1: PREPARE THE CONNECTION
1a. Prepare a stranded wire in accordance with Procedures 1 and 2A/2B on Stripping and Tinning, respectively.

1b. Insert a terminal into a phenolic block (or equivalent). Secure the block in a vise.

1c. Place the end of the stripped and tinned wire into the cup. The insulation shall not be imbedded in the solder joint, and shall be less than 2 wire diameters, including insulation.

Remove the wire and use wire cutters to cut the wire to the desired length. Re-cut the end of the wire as necessary. Conductors entering from the top shall be in contact with the inner wall of the cup and shall bottom in the cup or on the bottom conductor.

1d. Clean the terminal with an acid brush, using the approved solvent and a shopwipe.

1e. Tin the terminal by inserting the end of the solder into the cup and placing the iron so that it touches the solder and the side of the terminal at the same time. Fill the cup with solder to cover all of the inside surface.

Solder along the outside surface of the solder cup is permissible to the extent that it approximates tinning and does not interfere with the assembly or function of the connector.

1f. To wick the solder from the terminal, insert a stranded wire that has been coated with flux. Position the iron tip against the wire. The wire will get hot and melt the solder, which will then wick up into the strands of wire. Cut off the wire that has the solder wicked into it. Repeat the wicking process until there is no solder left to remove. The inside of the terminal will show a tinned surface. Repeat tinning and wicking until all gold is removed.

Gold plating on all surfaces, which becomes a part of the finished solder connections, shall be removed by two or more successive tinning operations, or by other processes demonstrated to have equivalent effectiveness.

1g. Clean the terminal with an acid brush, using the approved solvent and a shopwipe.

Step 2. POSITION THE WIRE
Attach the wire from the terminal to the spring, which will hold the wire during the soldering. Adjust the wire for the proper tension, centering, and position.

Step 3. CLEAN THE CONNECTION
Clean the connection with a soft brush, using the approved solvent and a shopwipe. Do not disturb the position of the wire.

Step 4. CUT THE SOLDER
Cut the end of the solder to expose the flux in the core of the solder. Wipe the solder with a shopwipe and solvent to remove any contaminants.

Step 5. CLEAN THE SOLDERING IRON
Prepare the iron by wiping the tip with a dry shopwipe. Lightly wipe the tip on a moist sponge to remove the oxides.

Step 6. POSITION THE IRON
Place the clean soldering iron tip against the terminal so as to contact both the wire and the terminal at the same time.

Step 7. APPLY SOLDER
Apply a small amount of solder to the junction where the wire, terminal, and tip meet in order to make a solder bridge. Add solder as needed to complete the soldered connection. Remove the solder; remove the iron.

Step 8. TIN THE IRON
Tin the iron tip while the connection is cooling at room temperature. A small amount of the solder should remain on the tip. Return the iron to the holder.


Step 9. CLEAN THE CONNECTION
Clean the flux from the soldered connection with an acid brush, using the approved solvent and a shopwipe.

Step 10. INSPECT THE CONNECTION
Inspect the solder joint under 4X to 10X magnification to the specified requirements.

The maximum number of conductors shall be limited to those that can be in contact with the full height of the inner wall of the cup. Free of flux residue and other contaminants. The surface shall be smooth and nonporous. It shall be undisturbed and have a finish that  may vary from satin too bright. The solder shall wet all elements of the connection. The solder shall fillet between connection elements over the complete periphery of the connection. The lead contour shall be visible. Proper insulation clearance.

For detailed inspection criteria refer to NASA-STD-8739.3, Paragraph 6 and Appendix A.

Terminal Swaging (Procedure 9)

Step 1: VERIFICATION TEST
1a. Verify the proper swaging tools for the terminal to be swaged. Swage type terminals in Non-PTHs designed to have the terminal shoulder soldered to the printed wiring conductor, shall be secured to the PWB by a roll swage.

PWB designs calling for soldering of the swaged end of the terminal to the printed wiring conductor on a single-sided PWB shall have the terminal secured with a V-funnel swage.

Swage type terminals that are mounted in a PTH shall be secured to the PWB by a V-funnel swage or an elliptical funnel swage. The elliptical funnel swage is the preferred method for attachment. Terminals shall be swaged such that they can be rotated under finger force.


1b. After the swaging press has been adjusted, use a sample board and swage a terminal. The swage, or flaring, should be inspected for the proper mounting according to the type of terminal. Elliptically swaged terminals shall be swaged such that they can be rotated under finger force.

Step 2. SWAGE THE TERMINAL
2a. Insert a terminal into the anvil.
2b. Position the PWB on the terminal.
2c. To swage the terminal, support the PWB while pulling the handle down to the stop.

Step 3. INSPECT THE SWAGE
Inspect the swaged terminals under 4X to 10X magnification to the specified requirements. Swaging of terminals shall be performed in a way that does not damage the PWB. After swaging or flaring, the rolled area of the flange shall be free of circumferential splits or cracks, but may have a maximum of three radial splits or cracks provided that the splits or cracks are separated by at least 90° and do not extend beyond the coiled or flared area of the terminal. Elliptical swages can be rotated under finger force.

Step 4. SOLDER THE SWAGED TERMINAL
Position the soldering iron tip so as to touch both the swage and the printed wiring pad at the same time. Apply solder to the junction where the iron and swage meet in order to make the solder bridge. Add solder as needed to complete the soldered connection. Remove the solder; remove the iron.

Step 5. CLEAN THE CONNECTION
Clean the flux from both sides of the soldered connection with an acid brush, using the approved solvent and a shopwipe.

Step 6. INSPECT THE SOLDERING
Inspect the solder joint under 4X to 10X magnification to the specified requirements.

Free of flux residue and other contaminants. The surface shall be smooth and nonporous. It shall be undisturbed and have a finish that may vary from satin to bright. The solder shall wet all elements of the connection. The solder shall fillet between connection elements over the complete periphery of the connection. The solder shall flow through a plated- through hole and bond to the lead and the solder pad on both sides of the PWB. A slight recessing or shrinkback of the solder onto the PTH below the solder pad is acceptable, providing the solder has wet the lead and on to the solder pad. Slight dewetting of the solder around the periphery of the pad on the part side of the PWB is not cause for rejection.

Axial Lead (Straight Through/Clinch — Resistor, Diode, Polarized Capacitor)(Procedure 10)

Step 1: PREPARE THE LEAD
All part leads should be tinned and formed before mounting the part.

Prepare the part lead by wiping it with a shopwipe and solvent to remove the oxides.

Attach a heat sink to those parts that require it. If necessary, apply flux to the surface to be tinned.

Clean the tinned lead with an acid brush, using the approved solvent and a shopwipe.


1a. Inspect the lead tinning. Hot tinning of solid conductors and part leads should not extend closer than 0.5mm (0.020 inch) to part bodies, end seals, or insulation unless the part configuration and mounting configuration dictate it. Conductor tinning personnel shall ensure that the tinned surfaces exhibit 100% coverage.

Step 2. BEND THE LEAD
2a. With a Lead Bending Tool
To find the correct measurement, place the bending tool between the holes into which the part is to be inserted.

Position the part into the proper slot for bending.

While holding the part body in the slot of the bender, use an orange stick to bend the lead.

2b. With Orange Stick
Hold the part in one hand. With an orange stick (sharpened to a point) held against the lead to be bent, place the thumb of the other hand on top of the wire. Now bend the lead to the proper angle as needed.

The minimum distance from the part body or seal to the start of the bend of a part lead shall be 2 lead diameters for round leads and 0.51 mm (0.020 in.) for ribbon leads. The stress relief shall not be less than the lead diameter or ribbon thickness. Where the lead is welded the minimum distance is measured from the weld.
Step 3. INSERT THE PART
Insert the leads into the holes of the PWB, and gently push the part until it bottoms against the PWB.

Part leads shall be formed so that they may be installed into the holes in the PWB without excessive deformation that can stress the part body or end seals.

Step 4. TRIM THE LEAD
Turn the PWB part side down. Place a measuring device on the PWB next to the lead in order to obtain the proper lead length. Cut the lead.

Straight-through leads may be bent up to 30° from a vertical plane to retain parts during the soldering operation. Part leads terminated straight through the PWB shall extend a minimum of 0.51 mm (0.020 in.) and a maximum of 2.29 mm (0.090 in.).

Clean the lead with a soft brush, using the approved solvent and a shopwipe.

Step 4a. CLINCH THE LEADS
Partially bend the lead in the direction of the trace. Cut the lead.

Using an orange stick, complete the bend.

The length of the clinched portion of the part lead shall be at least 1/2 the largest dimension of the solder pad or 0.78 mm (0.031 in.), whichever is greater. Fully clinched leads are defined as leads bent between 75° and 90° from a vertical line perpendicular to the PWB.


Step 5. SOLDER THE LEAD
Position the soldering iron tip so as to touch both the lead and the printed wiring pad at the same time. Apply solder to the junction where the iron and lead meet in order to produce a thermal (solder) bridge.

Touch the solder to the end of the cut lead to cover the exposed copper. Add solder as needed to complete the soldered connection. Remove the solder; remove the iron.


Step 6. CLEAN THE CONNECTION
Clean the flux from both sides of the soldered connection with an acid brush, using the approved solvent and a shopwipe.

Ultrasonic cleaning shall not be used for cleaning assemblies that contain electronic parts. After cleaning, there shall be no visible evidence of flux residue or other contamination when examined.

Step 7. INSPECTION
Inspect the solder connections under 4X to 10X magnification to the specified requirements.

The minimum distance from the part body or seal to the start of the bend of a part lead shall be 2 lead diameters for round leads and 0.51 mm (0.020 in.) for ribbon leads. The stress relief shall not be less than the lead diameter or ribbon thickness. The length of the clinched portion of the part lead shall be at least 1/2 the largest dimension of the solder pad or 0.78 mm (0.031 in.), whichever is greater. Part leads terminated straight through the PWB shall extend a minimum of 0.51 mm (0.020 in.) and a maximum of 2.29 mm (0.090 in.).

Free of flux residue and other contaminants. The surface shall be smooth and nonporous. It shall be undisturbed and have a finish that may vary from satin to bright. The solder shall wet all elements of the connection. The solder shall fillet between connection elements over the complete periphery of the connection. The lead contour shall be visible. The solder shall flow through a plated- through hole and bond to the lead and the solder pad on both sides of the PWB. A slight recessing or shrinkback of the solder onto the PTH below the solder pad is acceptable, providing the solder has wet the lead and on to the solder pad. Slight dewetting of the solder around the periphery of the pad on the part side of the PWB is not cause for rejection.

For detailed inspection criteria refer to NASA-STD-8739.3, Paragraph 13.6 and Appendix A.

Vertical Mount (Transistor, Disk Capacitor, DIP) (Procedure 11)

Step 1: PREPARE THE LEADS
Clean the leads. If necessary, add flux to the leads to be tinned. Tin the leads using a solder pot or solder iron.

Clean the flux from the leads.

1a. Inspect the lead tinning.

Hot tinning of solid conductors and part leads should not extend closer than 0.020 inch (0.51 mm) to part bodies, end seals, or insulation unless the part configuration and mounting configuration dictate it. 

Conductor tinning personnel shall ensure that the tinned surfaces exhibit 100% coverage.

Step 2. MOUNT THE PART
2a. Insert the tinned leads through the proper holes in the PWB.

PLATED-THROUGH HOLE. The end of the part body must be mounted with at least 0.51 mm (0.020 in.) to a maximum of 1.27 mm (0.050 in.) clearance above the PWB surface. The end of the part is defined to include any extensions such as coating meniscus, solder seal, or weld bead.

2b. DIP Insertion
Insert the dual-in-line package (DIP) into an approved ESD insertion tool, if required. Align pin 1 on the DIP with pin 1 on the PWB. Now insert the DIP pins into the PWB. Remove the insertion tool. 


Step 3. SOLDER THE LEADS
3a. Clean the lead and PWB.
3b. Place the PWB with part side down. Touch the soldering iron tip to the
circuit pad and the lead at the same time. Apply solder to form the thermal (solder) bridge. Feed enough solder to fill the plated-through hole and have a fillet on both sides of the board.

3c. After soldering the first lead of the DIP, inspect the lead on the part side of the PWB that the solder has flowed onto the lead and pad. Return to the bottom side of the PWB and solder a lead on the opposite side of the DIP to keep from overheating the part or the PWB. Continue this technique of soldering leads on the opposite side for each DIP.

Step 4. CLEAN THE SOLDERED CONNECTIONS

Step 5. INSPECTION
Inspect the solder connections under 4X to 10X magnification to the specified requirements.

The minimum distance from the part body or seal to the start of the bend of a part lead shall be 2 lead diameters for round leads and 0.51 mm (0.020 in.) for ribbon leads. The length of the clinched portion of the part lead shall be at least 1/2 the largest dimension of the solder pad or 0.78 mm (0.31 in.), whichever is greater. Part leads terminated straight through the PWB shall extend a minimum of 0.51 mm (0.020 in.) and a maximum of 2.29 mm (0.090 in.). 

Free of flux residue and other contaminants. The surface shall be smooth and nonporous. It shall be undisturbed and have a finish that may vary from satin to bright. The solder shall wet all elements of the connection. The solder shall fillet between connection elements over the complete periphery of the connection. The lead contour shall be visible. The solder shall flow through a plated- through hole and bond to lead and solder pad on both sides of PWB. A slight recessing or shrinkback of the solder onto the PTH below the solder pad is acceptable,  providing the solder has wet the lead and onto the solder pad. Slight dewetting of the solder around the periphery of the pad on the part side of thePWB is not cause for rejection.

For detailed inspection criteria refer to NASA-STD-8739.3, Paragraph 13.6 and Appendix A. 

Interfacial Connection(Procedure 12)

Step 1: PREPARE THE WIRE
Clean, flux, tin, and clean the solid wire. Repeat the tinning process as needed to assure a properly tinned wire.

Step2. INSERT THE WIRE
2a. Insert the wire through the hole of the PWB. Bend the wire over on both sides of the PWB onto the pad. Cut the ends of the wire to the proper distance.

The round lead shall overlap the solder pad a minimum of 3.5 times the lead diameter to a maximum of 5.5 times the lead diameter, but in no case less than 1.27 mm (0.050 in.). The cut-off end of the lead shall be no closer than 1/2 the lead diameter to the edge of the solder pad. A heel fillet is mandatory.

2b. Clean the lead and trace.

2c. Use tweezers to hold the lead in place. Tack solder one lead into place.


Step 3. SOLDER THE WIRE
3a. Turn the PWB over. Clean the lead on trace. Clean the iron. Solder the wire on this side. Tin and replace the iron. Clean the solder joint.

3b. Return to the first side of the PWB. Clean the iron.  Solder the wire. Tin and replace the iron. Clean both sides of the PWB.


Step 4. INSPECT THE CONNECTION
Inspect the solder joints under 4X to 10X magnification to the specified requirements:
 

  • Solder quantity.
  • Tinning of leads.
  • Flux residue or other contaminants.
  • Overlapped lead length.
  • Proper wetting.
Lapped Terminations (Flat Pack, Resistor) (Procedure 13)

Step 1: PREPARE THE LEADS
1a. BEND THE LEADS
Bend the leads by machine or bending fixture if possible.

1b. TIN THE LEADS
Attach a heat sink to those parts that require it.

Clean the leads. If necessary, apply flux to the leads to be tinned.


Tin the leads by solder pot. Axial leaded parts may be tinned with a soldering
iron.

Step 2. CLEAN THE LEADS
Clean the leads with a soft brush, using the approved solvent and a shopwipe.


STEP 3. MOUNT THE PART
Position the part near the place to be mounted. Clean the soldering iron by wiping the tip with a dry shopwipe. Wipe the tip on a moist sponge to remove the oxides. Pick up the part with tweezers and position it on the pads where it is to be mounted. DO NOT put pressure on the top of a part that might bend the leads.   While holding the part in the center of the mounting pad, touch the iron tip to one lead on each corner in order to reflow (tack) the solder.


Release the part, tin the iron tip, and replace the iron in the holder.

Stress relief shall be provided by forming the part leads at a bend angle to the PWB of not more than 95° nor less than 45°. The round lead shall overlap the solder pad a minimum of 3.5 times the lead diameter to maximum of 5.5 times the lead diameter, but in no case shall the length be less than 1.27 mm (0.050 in.).

Step 4. SOLDER THE LEADS
Choose a lead that has not been tack soldered. With a clean iron, position the tip to touch the lead and the trace at the same time. Position the solder to touch the back of the heel and the trace at the same time. When the solder has bridged between the heel and the trace, remove the solder. Add solder as necessary to form a concave solder fillet between the trace and edges of the lead. Remove the solder; remove the iron. Wipe the iron on a sponge. Solder the rest of the leads, alternating sides.


CAUTION: DO NOT SOLDER ADJACENT LEADS DUE TO HEAT BUILD-UP OF PWB AND PART.

Tin the iron, and return it to the holder.

Step 5. CLEAN THE CONNECTION
Clean the flux from the soldered connection with a soft brush, using the approved solvent and a shopwipe.

Step 6. INSPECTION
Inspect the solder connection under 4X to 10X magnification to the specified requirements. The minimum distance from the part body or seal to the start of the bend of a part lead shall be 2 lead diameters for round leads and 0.55mm (0.020 in.) for ribbon leads. The stress relief shall not be less than the lead diameter or ribbon thickness. 

Free of flux residue and other contaminants. The surface shall be clean, smooth, and nonporous. It shall be undisturbed and have a bright finish that may vary from satin to bright. The solder shall wet all elements of the connection. The solder shall fillet between connection elements over the complete periphery of the connection. A heel fillet is mandatory for lap soldered joints. Slight dewetting of the solder around the periphery of the pad on the part side of the PWB is not cause for rejection. Part marking shall be visible.

Continuous Run Wrap — Bifurcated (Procedure 14A)

Step 1: PREPARE THE CONNECTION
1a. Clean and tin the solid wire.

1b. Clean the wire and the terminal.

Step 2. POSITION THE WIRE
1a. Use an orange stick to tightly wrap the wire against the end terminal post.

Cut the end wires to 90° or 180°.

2b. Hold the solid wire with a finger and thumb between the two terminals. Allow the wire to loop between the terminals for a stress relief. Wrap the wire around the post of the terminal where it is to be soldered. Grasp the end of the wire with pliers and tighten the wrapped wire. Complete the wrapping of the terminals. 

2c. Wrap and cut this end terminal as in STEP 2a.

ALTERNATE PROCEDURE
Place the tinned bus wire between the terminals as shown. Clean the terminal and wire. Solder the terminals. Clean and inspect.


Hookup wire, solid or stranded, shall be supported by a means other than the solder connections or conformal coating if wire length exceeds 25.4 mm (1 in.). Attachment to a surface by staking with resin is adequate support.

Step 3. CLEAN AND SOLDER THE CONNECTIONS
Follow the steps in PROCEDURE 6 to solder and clean the wraps.

Step 4. INSPECT THE CONNECTIONS
Inspect the solder joints under 4X to 10X magnification to the specified requirements.

Side route conductors shall enter the mounting the slot perpendicular to the posts. A conductor may lay straight through a terminal slot provided the conductor surface remains in contact with the terminal surface. Conductors shall not extend beyond the diameter of the base except where physical clearance will not adversely affect environmental or electrical characteristics. Conductor bend shall be 1/4 (90°) to 1/2 (180°) turn.

Free of flux residue and other contaminants. The surface shall be smooth and nonporous. It shall be disturbed and have a finish that may vary from satin to bright. The solder shall wet all elements of the connection. The solder shall fillet between connection elements over the complete periphery of the connection. The lead contour shall be visible. Proper insulation clearance.

Continuous Run Wrap — Turret (Procedure 14B)

Step 1: PREPARE THE CONNECTION
1a. Clean and tin the solid wire.

1b. Clean the wire and the terminal.

Step 2. POSITION THE WIRE
2a. Cut the wire 180° to 270°. Use an orange stick to tightly wrap the wire against the end terminal post. 

2b. Hold the solid wire with a finger and thumb between the two terminals. Allow the wire to loop between the terminals for a stress relief. Wrap the wire around the terminal where it is to be soldered.  Grasp the end of the wire with pliers and tighten the wrapped wire. Complete the wrapping of the terminals.


2c. Wrap and cut this end terminal as in STEP 2a.


Step 3. CLEAN AND SOLDER THE CONNECTIONS
Follow the steps in PROCEDURE 5 to solder and clean the wraps.

Step 4. INSPECT THE CONNECTIONS
Inspect the solder joints under 4X to 10X magnification to the specified requirements.

Conductor bend shall be 1/2 (180° to 3/4 (270°) turn for conductors larger than AWG 26. Conductor bend shall be wrapped more than 1/2 (180°) but less than 1 (360°) turn for conductors AWG 26 and smaller. All conductors shall be confined to the guide slots. Conductors shall be maintained in contact with the post for the full curvature of the wrap and the conductor ends shall not extend beyond the base of the terminal. More than one conductor may be installed in a single slot of sufficient width, provided each conductor is wrapped on the terminal post and not on another conductor.

Free of flux residue and other contaminants. The surface shall be smooth and nonporous. It shall be disturbed and have a finish that may vary from satin to bright. The solder shall wet all elements of the connection. The solder shall fillet between connection elements over the complete periphery of the connection. The lead contour shall be visible.

For detailed inspection criteria refer to and NASA-STD-8739.3, Paragraph 13.6 and Appendix A.

High-Voltage Solder Joints (Procedure 15)

Step 1: PREPARE THE CONNECTION
Completely tin the terminal, and then solder a part lead or wire to a turret terminal in accordance with PROCEDURE 5 or to a bifurcated terminal in accordance with PROCEDURE 6. Inspect the solder joint under 4X to 10X magnification to the specified requirements.

NOTE: The terminal shall have no sharp peaks.

Step 2. PREPARE THE TUBING
Cut a piece of Teflon tubing long enough to fit over the terminal and down to the PWB. Now slot the tubing to fit around the wire. Position the Teflon tube over the terminal and attach a clamp at the base to hold it into place for soldering. 


Step 3. SOLDER THE TERMINATION
Clean the iron. Wipe the tip on a sponge. Position the iron in the end of the tube to touch  the terminal. Add solder to completely cover the terminal. Remove the solder. Wait until the solder thoroughly wets the terminal and visibly drops, then remove the iron. 

CAUTION: DO NOT OVERHEAT THE PWB.

Step 4. CLEAN THE CONNECTION
Remove the clamp and the Teflon tubing. Clean the flux from the soldered connection with an acid brush, using the approved solvent and a shopwipe.

Step 5. INSPECT THE CONNECTION
Inspect the solder joint under 4X to 10X magnification to the specified requirements. All elements of the termination shall be covered by a smooth fillet, free of discontinuity or severe change in contour. There shall not be any projections from part leads or solder spikes. 

Cold solder connection. Overheated solder connection. Fractured or disturbed solder connection. Poor wetting. Blowholes, pinholes, voids, and pits. Insufficient solder. Splattering of flux or solder on adjacent areas. Rosin solder joint. Contamination. Dewetting. Nonwetting. Part body in solder joint.

NOTE 1: Smooth webbing fillet between leads is acceptable.
NOTE 2: To rework the connection, wick the solder off and restart this procedure.