7.3.1 Soldering Surface Mount Chip Components, Point To Point Method

This procedure covers the general guidelines for soldering surface-mount chip components. This procedure covers the following surface-mount chip components. While all of these components are different, the techniques for soldering are relatively similar.

Chip Resistors
The component body of chip resistors is made of alumina, a highly durable, white-colored material. The resistive material is typically located on the top. Chip resistors are usually mounted with the resistive element facing upwards to help dissipate heat.

Ceramic Capacitors
These components are constructed from several layers of ceramic with internal metalized layers. Because metal heats up much faster than ceramic, ceramic capacitors must be heated slowly to prevent internal separations between the ceramic and metal layers. Internal damage will generally not be visible, as any cracks will be located within the ceramic body of the component. Avoid rapid heating of ceramic chip capacitors during soldering operations.

Tantalum Capacitors
These capacitors are electrolytic devices that use a sintered tantalum anode and a thin oxide dielectric to achieve high capacitance in a small volume. They offer excellent stability, reliability, and low leakage current, making them a common choice in compact and high-performance electronics, such as medical devices, military systems, and communication equipment. Available in both solid and wet electrolyte versions, solid tantalum capacitors, particularly those using manganese dioxide or conductive polymer cathodes, are favored for their long service life and consistent electrical characteristics.

When hand-soldering tantalum capacitors, care must be taken to avoid rapid or excessive heating. A sudden temperature rise can cause the encapsulation to crack, damage the oxide dielectric, or degrade the cathode material, resulting in leakage or catastrophic failure. To prevent heat-related damage, the soldering temperature should be kept below 260°C (500°F), and the contact time should be limited to just a few seconds. Preheating the assembly and avoiding direct heat on the capacitor body helps reduce thermal stress and preserve component reliability.

Plastic Body
Another style of chip component has a molded plastic body that protects the internal circuitry. There are several types of components that share this exterior package design. The termination styles for plastic chip component packages vary considerably.

MELF
Metal Electrode Face cylindrical components. These may be capacitors, resistors, and diodes. It can be challenging to distinguish them apart, as there are no universal color codes or component designators printed on the component bodies.

Minimum Skill Level - Intermediate Recommended for technicians with skills in basic soldering and component rework, but may be inexperienced in general repair/rework procedures. Conformance Level - High This procedure most closely duplicates the physical characteristics of the original, and most probably complies with all the functional, environmental and serviceability factors.

Acceptability References IPC-A-610 12.0 Surface Mount Assemblies

Procedure References 1.0 Foreword 2.1 Handling Electronic Assemblies 2.2 Cleaning 2.5 Baking And Preheating 7.1.1 Soldering Basics 7.1.2 Preparation For Soldering And Component Removal 7.1.3 Solder Joint Acceptability Criteria IPC7711 5.3.1 Solder Paste Method

Tools, Materials and Supplies Flex-Rack PCB Holder Sturdy rack for PCBs used for rework and positioning. Cleaner General purpose cleaner for removing contamination. Hot Plate Temperature adjustable heated plate to pre-heat components and circuit boards prior to tinning and reflow. Microscope Precision microscope with stand and lighting for work and inspection. Precision Tool Set Nine precision-crafted tools for detailed circuit board work. Soldering Skills Practice Kit Training kit to practice circuit board soldering skills prior to testing for certification. Soldering Iron Properly maintained soldering iron and properly sized soldering iron tips. Tweezers Multiple sizes and tip configurations of tweezers for various small parts handling needs. Wipes Nonabrasive, low-linting wipes for cleanup.