6.4 Component Lead Cutting and Lifting

Outline

This procedure covers the general guidelines for modifications that involve cutting and lifting component leads. Leads may be permanently cut or lifted due to engineering changes or reconnected if done for testing purposes.

Minimum Skill Level - Advanced

Conformance Level - Medium

Tools and Materials

Cleaner General purpose cleaner for removing contamination.

Cutters and Pliers Precision grade cutters and pliers.

Flex-Rack PCB Holder Sturdy rack for PCBs used for rework and positioning.

Microscope Precision microscope with stand and lighting for work and inspection.

Mixing Picks Disposable mixing sticks for mixing and applying adhesives.

Precision Tool Set Nine precision-crafted tools for detailed circuit board work.

Probe Sharp dental-style probe for manipulating small objects and removal of debris.

Soldering Iron Properly maintained soldering iron and properly sized soldering iron tips.

Wipes Nonabrasive, low-linting wipes for cleanup.

Procedure

Note: Specially designed cutters are required when cutting component leads.

Procedure - Lead Cutting, Plated Through Hole Components

1. Select the component lead that needs to be cut and place the cutter in position. (See Figure 3) Place the cutter at the midpoint in the lead and snip through to cut the lead.
2. To ensure that the lead has been severed, the upper portion of the lead may be slightly lifted using a pick. Visually inspect or electrically test to ensure that the lead has been severed.
3. If the lead needs to be reconnected, gently push the upper portion of the severed lead down until it touches the lower portion of the severed lead.
4. Solder both halves of the severed lead together. (See Figure 5)
   Note: The lower portion of the lead may move during soldering since it is not anchored in position.
5. If required, clean the flux residue and inspect.

Procedure - Lead Cutting, J Lead Components

1. Select the component lead that needs to be cut and place the cutter in position. (See Figure 6) Place the cutter at the midpoint in the lead and snip through to cut the lead.
2. To ensure that the lead has been severed, the upper portion of the lead may be slightly lifted using a pick. (See Figure 7) Visually inspect or electrically test to ensure that the lead has been severed.
3. If the lead needs to be reconnected, gently push the upper portion of the severed lead down until it touches the lower portion of the severed lead.
4. Solder both halves of the severed lead together. (See Figure 8)
   Note: The lower portion of the lead may move during soldering since it is not anchored in position.
5. If required, clean the flux residue and inspect.

Procedure - Lead Lifting, Standard Gull Wing Components

1. Select the component lead that needs to be lifted. Apply a soldering iron and solder braid to remove the excess solder from the joint.
2. Gently place a pick behind the component lead to be lifted. Apply a soldering iron tip to the foot of the component lead. Apply slight force with the pick to lift the lead as the soldering iron reflows the joint. (See Figure 9)
3. Visually inspect or electrically test to ensure that the lead has been lifted. See (Figure 10)
4. If the lead needs to be reconnected, gently push the lead down until it touches the pad and solder.
5. If required, clean the flux residue and inspect.

Procedure - Lead Lifting, Fine Pitch Gull Wing Components

1. Select the component lead that needs to be lifted. Apply a soldering iron and solder braid to remove the excess solder from the joint.
2. Gently place a pick behind the component lead to be lifted. Apply a soldering iron tip to the foot of the component lead. Apply slight force with the pick to lift the lead as the soldering iron reflows the joint. (See Figure 11)
3. Visually inspect or electrically test to ensure that the lead has been lifted. See (Figure 12)
4. If the lead needs to be reconnected, gently push the lead down until it touches the pad and solder.
5. If required, clean the flux residue and inspect.

Images

Component Lead Cutting and Lifting

Specially designed cutters used to cut component leads.

Place the cutter at the mid point in the lead and snip through to cut the lead.