Solder Stations and Soldering Testers

Soldering is the process of joining two or more components by melting and filling a metal (solder) into the joint. A soldering station is a multipurpose power device designed to solder electronic components such as PCBs. The station houses several soldering tools connected to the main unit, such as the controls (temperature and voltage controls) and means of indication. It may also be equipped with an electric transformer. Modern solder stations also include solder iron holders, stands, soldering tip cleaners, etc.

Solder iron is the most critical component in a soldering station, fusing the metal and joining two or more electronic components. The soldering iron has a metallic tip at one end and a thermal/electrically insulated handle attached. Electric current is passed onto the soldering iron, and due to electrical resistance, the metallic tip is heated, which in turn melts the metal and fuses the components. Solder Pencil and Solder Gun are the two solder irons widely used in the industry. Soldering pencil is used for low-duty applications such as household appliances and is compact in design. Soldering guns draw amperes of current and are used for enterprises and other heavy-duty applications.

Types of Solder Stations:

Soldering stations are commonly used across industries, workshops, electronics repairing, and electronic laboratories. Depending on the functional characteristics and application, soldering stations are classified into five types:

1. Tin or Lead Soldering stations: These are contact-type, traditional soldering stations integrated with a built-in power supply unit to ensure galvanic separation between the power circuit and the heating element. The voltage on the heating element may be adjusted using the power supply unit, and accordingly, the heating temperature may be changed. For contact solders, the optimal soldering temperature range is 250-330 °C, at a power not exceeding 50-60 W.
2. Lead-free contact soldering stations: Like traditional Tin or Lead solder stations, they operate through a power supply unit to heat the metal. Because of environmental restrictions, Lead-free metals are used to join the metals. The heating element power ranges from 75-80 W up to 150-160 W. To minimize temperature stabilization, advanced PID controls are used in modern soldering stations. However, due to the development of miniature SMD components and leadless BGA chips, using contact soldering methods is extremely difficult and impossible for accurate jobs. Hence, non-contact type soldering techniques were developed.
3. Hot air soldering stations: A type of non-contact soldering, hot air soldering stations avoid metal contact while soldering. This method is widely used for repairing cell phones and household appliances. The power of any such station is only sufficient for operation with lead and lead-free soldering alloys. Due to their low power drawing ability, these stations cannot be used for large BGA chips soldering/desoldering.
4. Desoldering stations and Rework stations: This non-contact solder technique uses compressors to blow in the melted metal instead of blowing out. With the compressor, the heated solder on a contact surface is blown into a particular receiver. Though the working principle appears complex, the operation of the desoldering station is simple.
5. Infrared soldering stations: IR stations have almost wholly displaced other types in PC and laptop service centers. Two types of IR stations are common: ceramic and quartz-type soldering systems. IR systems use infrared radiation to heat the metal and join electrical components. The advantage of Quartz IR stations is their high reliability and long mean time between failures, and Quartz heaters have low persistence and uniform homogeneity of the heating spot.

Depending on the application requirement, solder stations are integrated with temperature and voltage control systems to heat the fuse metal optimally. Constant-voltage soldering stations are temperature-limited but do not incorporate a temperature sensor. They depend on the increasing thermal resistance of the heating element to limit tip temperature. Due to the constant voltage power supply, line voltage fluctuations and ambient temperatures significantly affect the temperature of the soldering tip and affect the fusing job and so require highly skilled operators to perform the task. However, constant voltage stations are commonly used as they are the least expensive amongst all soldering irons.

Variable-temperature soldering irons incorporate a temperature-control device in the soldering handle. A control knob on the power source controls the voltage passed through the soldering iron, varying the tip temperature. When the soldering tip achieves the prescribed temperature, the current to the heater is turned off. The tip cools to the lower temperature setpoint of the controller, and the current to the heater is turned back on. Tip temperature calibration is possible with variable-temperature soldering irons. This type of iron can be adjusted so that its temperature is balanced with the thermal requirements of the joint.

Selection of Soldering Station:

When selecting a soldering iron, potential damage to the PCB and its components must be considered. Damage can result from excessive joint temperatures or electrical overstress. Thermal damage can result from an iron that is not temperature controlled or is operated at too high a temperature. In contrast, electrical overstress results from the flow of electrical energy (leakage or electrostatic) when the iron is placed in contact with the component, which damages or weakens an electrical part. Therefore, in addition to the application (contact or non-contact type soldering), three factors are critical for the selection of a soldering station:

1. Wattage: Most solder stations range in between 20W-60W. Higher wattage can be used for industrial and commercial applications.
2. Temperature control: Operating temperature of solder iron is decided based on the fusing metal and the melting point of the component to be joined. Temperature-controlled systems are required for workshops where a variety of electrical systems are soldered.
3. Tip shape and size: Depending on the size of the joint, tip size has to be selected. Several detachable solder iron tips of various shapes and sizes are available for commercial use and chosen according to the project.

Soldering Testers – Types and Principle of Operation:

Soldering Testers are designed to test and examine hand-held soldering irons used in the assembly of electronic components. These testers are often used as a quality tool to assist manufacturers in complying with Soldering Standards IPC/EIA J-STD-001C. Solder testers validate the performance of solder stations by measuring the Temperature, AC voltage, AC and DC voltage, and Resistance to Ground values. Modern testers can detect voltage spikes on the soldering iron tip, which hampers the soldering process.

Solder Stations and Testers Calibration – Why is it Essential?

Appendix A of the IPC-J-STD-001 details the calibration standards of soldering stations/irons. The critical parameter to be tested on a solder station is the temperature response of solder housing for the current supply at various loads. According to the guidelines, these loads should not impact the physical temperature more than +10 degrees C, and the validation procedure is mentioned below:

1. All temperature-controlled soldering stations should demonstrate control within +/- 10C [+18F] of their operator selected or rated temperature when a minimal static load sufficient for validation measurement is applied to the tip.

2. Temperature stability is defined as temperature degradation to peak recovery. Temperature shall be checked at various point-to-point soldering loads, and the temperature shall not exceed the temperature control limits defined in Point 1.

3. Temperature stability, defined as temperature degradation to recovery overshoot, shall be checked following the multiple load point to point soldering and shall not exceed the limits specified in point 2.

In addition to the points mentioned above, tip-to-ground potential and tip-to-ground resistance should be within the OEM-defined operating limits. The following points describe why is calibration essential for Solder stations and testers:

• Changing the shape of a tip impacts the temperature accuracy and changing the heating source (heating element or cartridge) has a more significant effect. Therefore, Calibration is essential.

• An unskilled or inattentive operator can leave the temperature at the highest setting (for temperature-controlled irons), which can permanently damage the material composition of the iron or the tip.

• With the inclusion of several solder manufacturers into the market, maintaining quality control is of utmost importance to managers to avoid costly equipment failures, reworks, and downtime losses. Therefore, to prevent project failures, it is critical to timely calibrate the solder housings.

Cumulative errors often result in operational uncertainties, affecting the accuracy of the soldering process. Calibration avoids these errors, ensures the soldering station and testing kit accuracy for sustained and repeated use, and enhances service life. Following a regular and timely calibration schedule ensures accuracy of measurement and improves process accuracy.

e2b calibration offers industry-leading ISO-certified solder station and tester calibration services. Our labs are ISO/IEC 17025 accredited and operated by a team of qualified calibration experts to test and calibrate your soldering kits. Our verifiable services are unmatched in the industry. We are registered with ANAB. We are also ANSI/NCSL Z540-1-1994 certified. We have the NIST Traceable Wide scope of ISO/IEC 17025 accreditation. Contact e2b calibration for all your equipment calibration needs.