Soldering: Having the right tools matters

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To create a strong physical bond between two metals, it is essential to have the right soldering tools for different types of soldering jobs and temperatures.

By Potshangbam July

Having the right tools is certainly crucial when executing an electronics projects. Besides getting the job done smoothly and safely, it considerably increases the speed of the work. When it comes to soldering processes for electronics projects, many presume that all we need is a good soldering iron and some solder wire. But the right tools can make a huge difference – they can ease the soldering process and improve the quality of the work too.

Essentials tools for soldering

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Even though you can do a lot with just a soldering iron, getting a few extra tools makes things a lot easier. As a matter of fact, these tools are meant to simplify the soldering process.

Here are a few basic soldering tools that can help perform tasks with comfort.

Soldering iron: This is the most important tool for soldering. Its effectiveness depends on tip sizes, styles and the wattage. The wattage determines how fast the soldering iron heats up. When you solder, heat is transferred away from the soldering iron tip to the solder joint. High wattage makes it easier for the tip to maintain a high temperature. And with changeable tips, you can choose the correct one for the type of soldering you are doing.

Soldering stands: Soldering stands are essential for keeping the soldering tip clean and, of course, for safety reasons. The soldering iron gets heated after a certain time; so it is important to keep it in a safe place to avoid any fire mishaps. Instead of balancing it at the edge of the work table, a stand holds the hot iron safely.

Wire cutters: They come handy to cut long component legs and to strip the wire. They are also called electronic snippets, diagonal cutters, flush cutters, clippers, etc. The size of the wire cutter chosen is important and should depend on the type of work it is required for. Smaller wire cutters are recommended for PCB work, and larger versions for general wiring.

Thin nose pliers: These too should be selected as per the type of work envisaged—smaller ones for general circuit board work, and larger ones for heavy duty work.

Solder suckers (solder pumps): These are mechanical vacuum pumps used to remove solder from the solder joint. The solder joint needs to be heated up to melt the solder wire, and then the vacuum pump sucks off the excess solder. This makes it possible to rework.

Tweezers: These are used to avoid burning when soldering. They are also used to place components in the circuit board.

Solder wick: The solder wick is another tool for removing a small amount of solder. It is made of copper threads that absorb the solder from the solder joint. It is used to remove small quantities of the solder left on a bigger solder joint, when the solder sucker does not work.

Helping hands: These hold your components together while you solder, leaving your hands free to perform your work. Helping hands come in all sorts of models with different accessories and features. Some come with built-in LEDs, a magnifying glass, a soldering iron holder, flexible hands, and much more.

PCB clamp: This comes in a variety of different styles. One type that is particularly useful has a plate and a foam back to place over the component side of the board. This holds the components in place as they are soldered.

Soldering mat: To prevent damage to your desk during soldering, you can use such a mat. It is heat-resistant and also has mini compartments to place electronics components or screws while disassembling appliances.

Types of soldering

There are two standard types of soldering – soft soldering and hard soldering. Each has its own processes that require different tools.

Soft soldering: In the case of soft soldering, the soldering iron can be used to heat the metal, which should be below 400°C (752°F). The solder metals are typically alloys (often containing lead) that have a melting point below 350°C. In this process, soldering is used for joining small intricate parts with low melting points. If the soldering process is carried out at a high temperature, it damages components.

Hard soldering: Hard soldering is done at a much higher temperature, when the solder material has a high melting point of above 450°C (840°F). In this process, the hard solder connects two pieces of metals by expanding into the pores of the work piece opened by high temperature.

The importance of maintenance

To prolong the life of the soldering iron and other allied tools, regular maintenance is crucial. The tools require continual cleaning in order to work quickly and efficiently.

Do not let the soldering iron and tip get dirty. Impurities can get transferred from the solder tip to the soldered joint every time they touch. When the soldering iron gets hot, clean the tip often with a tip cleaner and a moist sponge or paper towel. This should be done before and after each solder joint has been worked on. Remember: A dirty soldering iron will make terrible solder joints.

Also, when the soldering iron is hot, the tip needs to be ‘tinned’ with solder to get it shiny and clean and to remove any dross or rosin. Tinning also helps prevent oxidation. To tin the tip, get your soldering iron hot and then coat the tip with solder. Your tip should look like chrome or silver.

Safety precautions

As with all electrical or mechanical devices, soldering tools should be handled with extra care to avoid any accidents. The soldering iron and tip often reach extremely high temperatures of 93°C (200°F and above) which is hazardous if not dealt with a bit of alertness and caution. Listed below are a few safety precautions to keep in mind while dealing with soldering equipment:

  • The soldering iron should not be held at the same spot for a long period of time. Otherwise, it will damage sensitive components or burn up a circuit board. You should solder quickly so that your components or traces don’t stay hot for too long.
  • The tip of the soldering iron should never be touched. It is very hot and can cause serious burns.
  • The hot iron or tip should not be dipped in cold water or any liquid when in a hurry to cool it.
  • Flammable or explosive materials should not be kept near the soldering area.
  • Put the soldering iron on its stand when not in use. Never make the mistake of placing it on the workbench, which is dangerous.
  • Always unplug the soldering iron when you have finished using it. This will help prevent oxidising and burning up the tip.
  • Always work on a clean surface and in a well-ventilated work place.

Points to consider when purchasing soldering tools

One of the most important things is to use good quality solder. When the solder is of inferior quality, the impurities collect on the tip of the soldering iron, which hinders the transfer of heat. Consequently, it affects the solder joints that become weak over time. It is also important to select the correct type and composition of solder.

When selecting the soldering tip, a small tip should always be given priority. The tips should be interchangeable. It is recommended to buy a few extra tips so that they are handy when replacements are required, which happens quite often.

For the soldering iron, it is better to look for one of a higher wattage (preferably between 20 and 50 watts), which can maintain a stable temperature over longer periods of time. This is because the tip of the solder iron cools quickly as the heat is transferred to the solder and the joints.

Some soldering tools that are available in the market

Product: Soldron metal body desoldering pump; Manufacturer: Vimla Engineering

This economical full-metal body desoldering pump comes with a heat-resistant replaceable silicone tip. This product has good desoldering capabilities due to strong suction and a durable build.

Key features:

  • Durable
  • High temperature capability
  • Highly efficient for de-soldering purposes

Contact details: www.soldron.com

Product: WE1010; Manufacturer: Weller

The WE1010 is the latest offering in the company’s Efficiency line. This 70-watt station is for production units in the electrical, electronics and automotive segments. It is also suitable for cable assembly jobs as well as for the education segment and hobby projects.

Key features:

  • ESD safe, single-channel power unit of 70 watts, which the company claims is 40 per cent more powerful than regular 50 watt stations in the same category; has good recovery time.
  • ESD safe ergonomic 70 watt soldering iron—WEP 70 with heat resistant silicon cable. No extra tools required for tip change.
  • Comes with a new reinforced safety rest called the PH70. Easy to use, with double-layered sponge.
  • Tips can be changed when the iron is hot, thanks to a plastic knurled nut provided on the handle without any additional tool.
  • Temperature stability: 2°C (+/- 4° F)
  • Intuitive navigation: State-of-art housing with LCD display and three easy-to-operate push buttons; single dedicated switch for the menu and all-new SW features.
  • Standby mode: Station automatically powers down to a given temperature when not in use. Great savings on power and consumables like tips/barrels.
  • Automatic set back: Sets temperature back automatically when in use, saving time.
  • Password protection: All settings can be secured with a password.
  • Easy to calibrate: Built-in feature for calibration and offset.
  • Tip compatibility: Station is compatible with time-tested Weller ET tips with many geometrical options like chisel, round, conical and gullwing.
  • Most important, this station is cost-competitive, offering a high ROI because of the low cost of tips and consumables.

Contact details: www.weller-tools.com

Product: Solder-wick unfluxed desoldering braid; Manufacturer: Chemtronics

Its geometrically precise weave design allows for maximum capillary action and solder capacity. It optimises heat transfer through the braid and into the solder joint, resulting in faster wicking action.

Key features:

  • Can be coated with any flux type
  • Allows for a constant flux type throughout the production process
  • Provides quick and safe desoldering
  • 3.048m spools packaged in ESD-safe static dissipative bobbins

Applications:

  • To be used with the specified flux type throughout the production process

Specifications:

  • MIL-F-14256 F
  • NASA-STD-8739.3 Soldered Electrical Connections
  • DOD-STD-883E, Method 2022
  • ANSI/IPC J STD-004

Contact details: www.chemtronics.com

Product: Helping hand soldering station; Manufacturer: Elenco

This all-round station comes with three helping hands. They grip the work piece securely while positioning it under the magnifying glass for certain applications. This station offers proper support as it comes with large alligator clips. It has an LED light to help work even in poorly lit stations.

Key features:

  • The base is very stable.
  • The magnifying glass has a long flexible neck.
  • It includes two spools and a soldering iron.

Contact details: www.elenco.com

Product: Soldering iron of 8 watt/230 volts; Manufacturer: Noel

This 8-watt soldering iron is used for high precision and unique soldering purposes. It is very sharp and used where soldering has to be done very meticulously.

Key features:

  • Advanced heating element
  • High quality copper plated bit
  • Quickly reaches a working temperature
  • Constant tip temperature
  • Low current leakage
  • Two-core moulded plug
  • Strong ABS handle for comfort

Contact details: www.noelindia.com

Sourabh Tiwari, sales manager, Weller, shares his insights into the current soldering practices, including the essential tools used, the latest trends, the market scenario and much more.

The importance of having the essential tools for soldering

The correct soldering tools play a very important role in the soldering process as they simplify the job of an operator. It is important that mechanical and electronic strength is achieved in a soldering joint with proper tools. The following tools are a must for the best soldering practices:

  • Station: A temperature controlled soldering station, with wattage according to the application’s requirement, an accuracy of +/- 9°C and a stability of +/- 2 per cent is needed. The joint gets soldered quickly at the right temperature.
  • Sleek soldering iron: This should have the correct wattage for the application and the latest technology. Operator comfort when holding and operating the soldering gun is important.
  • Tips: Cost-effective tips of different types like chisel, conical or round of suitable dimensions, ensure operator comfort. Gull wing tips are best suited for drag soldering applications.
  • Soldering stand: This should be suitable for the particular soldering iron and come with the wet clean and dry clean provision; stop-and-go stand reduces tip oxidation and it is easy to place the soldering iron on it, post use.
  • Accessories like precision cutters, pliers, strippers, desoldering wicks, guns, pumps, etc help in the soldering process. Special tools from EREM (Swiss-based precision hand tools manufacturer) make it easy for users to cut/hold components.
  • Good micro tweezers make desoldering of micro SMD components easy.
  • Extraction system: Hazardous gases generated during soldering get extracted, purifying the air and avoiding health issues.

Latest trends in soldering tools

Hand soldering has become very critical as the boards are getting smaller with an increased density of components on boards, as well as the use of ball grid array (BGA) ICs and quad flat no-lead (QFN) ICs.

To address this, new heating technologies are being used.

  • Cartridge tips/active tips: Tips with inbuilt heating elements and smart sensors are used to meet high heat requirements, for example-microsoldering/desoldering work under the microscope.
  • Visual process control: Smart sensors with an LED for standby operation.
  • Temperature accuracy and response time: There has been increased demand for high temperature accuracy and fast response times (ultra-quick temperatures rise post-solder joint/heat dissipation).
  • Different features are now possible with smart soldering stations—tool detection, integration with the traceability process, robot output, integrated parameter memory, USB port for firmware update, flexibility for equipotential bonding, capability to integrate with accessories like fume extractors, heat plates, computers, etc.
  • Smart energy saving: This feature is required by almost all production units to save on energy and consumable costs.
  • Smart two-sided heated/four-sided heated nozzles to address DIP and other packages.

Maintenance/safety tips of soldering tools

Maintenance of a soldering station plays an important role in extending the life of stations/consumables. As ROHS compliance is now mandatory, temperature requirements for soldering have increased by almost 50°-70°C.

Optimum temperature: The station has to be used at the optimum temperature—not higher than what the process requires.

Use of a tip activator: Oxidation of the tip can be controlled to a great extent by the use of a tip activator

Using standby mode: Standby mode increases the life of the tip/consumables by dropping the tip temperature to lower than the predefined temperature when not in use.

Use of dry clean/brass wool: Using brass wool rather than the wet sponge results in increased tip life, unless the latter is a process requirement. Regular changing/cleaning with the brass wool is also very important.

Use of preheating plates: Certain boards that require very high temperature can be soldered on preheated plates to reduce soldering time and extend tip life.

Purchasing tips

Different sectors have different requirements—for example, production units need soldering stations with a precise temperature and accuracy but may not need many features that are not used regularly. ROI is the main concern for production units, where the station cost and tip cost is very important. For R&D applications, the response time, accuracy and many other built-in features are important. Specifically, integration with the process/traceability becomes very important. Cost, of course, is the second most crucial factor. In general, one should always look for a supplier with a wide range of products and with a very good reputation in the market.

Indian market scenario

India is a fast expanding electronics market and the demand for quality soldering products is increasing, as is the awareness of customers on soldering technologies. Customers are now demanding quality products and understand the benefits of a one-time investment in a good soldering station rather than replacements every now and then. Service and distribution networks are equally important. With many new EMS companies opening their plants in India and the increasing demand for electric vehicles, solar power generating equipment, aerospace and defence applications, etc, the demand for soldering tools is expected to grow in the future.

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