Knocking Down the Bone Pile: 5 Habits to Make Your Soldering Iron Tips Last Longer

Poorly maintained soldering iron tips have real costs associated with their lack of care. The replacement costs associated with failing soldering tips, as well as the negative impact on outgoing quality levels, are the two greatest costs related to poor tip management practices. A poorly maintained soldering tip can result in ineffective heat transfer, which means that a reliable intermetallic interconnection is difficult to ensure. To maintain the integrity of the soldering joints and prevent the tips from becoming a runaway consumable expense, there are several areas of tip care that can prolong their life.

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Figure 1: An example of a degraded blade tip.

When to Replace the Tip
There are signals to the rework technician that a soldering tip is beginning to fail. If solder on the tip tends to “pool up” rather than flow across the tip, then surface oxidation may be going on in the tip. This will lead to a poor heat bridge and limited heat transfer. Another sign of oxidation buildup will be a drop in soldering performance. If it seems like the iron is just not getting hot enough, it could be that a thermal barrier of oxidation is preventing the tip from doing its job.

Another telltale sign is in the visual appearance of the surface of the tip, which should have a luster and shininess to its visual appearance. The soldering iron tip plating material should show that it is intact by not displaying any signs of pitting, holes, or cracks in the tip plating. All of these are signs that the tip needs a replacement.

Keeping the Tip Clean
One of the habits that rework technicians need to nurture is keeping the soldering tip clean. Clean tips will help ensure that they last longer and work most efficiently during their lifetime. Ideally, the tip should be cleaned frequently during use and after every shift. There are multiple methods for cleaning the soldering iron tip.

One technique is wiping the tip on a damp sponge wetted via distilled or DI water (to reduce any mineral buildup on the tip). Be sure to let the tip return to the set temperature between each of the wipes as the sponge will cool the tip. Change these sponges periodically so as not to re-contaminate the tip. As an alternative, brass wool can be used to gently scrub the iron plating on the tip without damaging it. Sandpaper and files should never be used to clean the tip of a soldering iron as this will damage the plating material and cause premature tip failure.

Most tip cleaners contain highly aggressive chemicals and should be avoided, as buildup can lead to blackening of the tips and oxidation of the plating. Due to the numerous heat cycles and the many different coatings, fluxes, epoxies, and other materials found in the rework area, cleaning may need to be on a more frequent basis compared to other areas of the manufacturing floor; thismaintains tip life and ensures solder joint integrity.

Tip Tinning
Once cleaned, one of the best ways to extend the life of your soldering iron tip is to apply solder so as to protect it from oxidation and premature failure. Tip tinning helps prevent oxidation, which hinders the tip from transferring heat effectively. Simply flood the tip with solder before putting it into the holder. This layer of solder works to protect and seal the iron plating from the air, thereby inhibiting oxidation. The other benefit to tip tinning is that it creates a heat bridge, which can effectively transfer the heat from the soldering iron to the pad as well as the component leads.

Storage and Handling
In addition to cleaning and tinning of the tip, their life can be extended through proper handling and storage. It is recommended that tips be stored in a container to limit the effects of oxidation, corrosion, and debris accumulation. Never bang or drop the tip, as this can cause damage to the plating or heating cartridge. Through proper storage and handling, tip life can be extended.

Understanding the Role of Flux

Tip plating can be eroded and altered by flux as activators found therein can damage the plating of the tip through a chemical reaction. More aggressive fluxes such as rosin-based or water-soluble fluxes can act more aggressively in wearing the tip plating away. It is not advised to dip your soldering iron tip into the flux as it could prematurely damage the plating. Instead, flux should be applied at the interconnection point of where the solder is applied at the pad/lead interface and never directly to the tip itself to protect tip life.

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Figure 2: Chisel tip plating erosion.

Maintaining the Right Tip Temperature
Tip temperature has a big impact on the expected life of the soldering iron tip for a number of reasons. Fluxes and cleaning agents coming into contact with the soldering iron tip under increased temperature can accelerate the degradation of the tip coating. Oxidation of the tip increases under higher temperatures. Finally, the thermal stress on the tip increases with increased temperature, thereby inducing a greater rate of tip degradation.

In some soldering stations, the soldering iron can go into a “sleep” mode to increase tip life, which greatly reduces the temperature of the tip while it is not in use. By understanding the impact of temperature on tip life, rework technicians can prolong the life of their soldering iron tips.

Conclusion
By following these guidelines for soldering tip maintenance, more consistent and reliable hand soldering rework results can be obtained while reducing the consumable costs associated with the purchasing of many tips.

Bob Wettermann is the principal of BEST Inc., a contract rework and repair facility in Chicago. For more information, contact info@solder.net.

This column originally appeared in the November 2020 issue of SMT007 Magazine.

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2020

Knocking Down the Bone Pile: 5 Habits to Make Your Soldering Iron Tips Last Longer

11-02-2020

Poorly maintained soldering iron tips have real costs associated with their lack of care. To maintain the integrity of the soldering joints and prevent the tips from becoming a runaway consumable expense, Bob Wettermann shares several areas of tip care that can prolong their life.

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Knocking Down the Bone Pile: PCB Rework of 0201 Packages

09-07-2020

As electronic passive components continue to shrink in size, methods for their rework need to be developed by electronic manufacturers to maintain and support PCB assembly processes. Bob Wettermann compares and outlines a few of these rework methods.

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Knocking Down the Bone Pile: Removing Conformal Coatings for PCB Rework

07-27-2020

When the removal and replacement of components due to field failures or manufacturing defects needs to occur, the overlaying conformal coating layer first must be removed before being able to remove and replace a component. Bob Wettermann explains.

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Knocking Down the Bone Pile: Getting to the Root Cause of BGA Assembly Problems

05-04-2020

When potential process defects begin showing up underneath BGAs in electronic assemblies, there are numerous failure analysis tests that can be used to troubleshoot process problems. These investigative methods begin with non-destructive test methods and progress to destructive methods as some of the possible root causes are eliminated.

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Knocking Down the Bone Pile: Underfill Rework and Solder ‘Squirt Out’

01-02-2020

One of the toughest rework challenges is removing and replacing components on PCBs with underfilled components. Many times, underfill is used to provide a shock barrier to component solder joints of handheld electronics, such as notebooks, tablets, and phones. This underfill is added post-test in the assembly process and is dispensed underneath components, such as BGAs, QFNs, and LGAs.

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2019

Knocking Down the Bone Pile: Electronics Assembly Industry Outlook

12-17-2019

Geographically, our products go directly into the market around the world, our rework and repair services are a harbinger of the EMS build market, and our training services are hyper-focused in the Midwest of the United States. Therefore, we see much of the activity in the global electronics supply chain. There are numerous PCB rework/repair challenges being faced by North American customers. One trend has to do with increasing package sizes, which are being driven by the market desires. In the past five years alone, the state-of-the-art semiconductor package has gone from approximately 10 to 30 billion transistors on a single package.

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Knocking Down the Bone Pile: Process Methods for Reworking High Lead Count SMT Parts

10-09-2019

There are numerous methods for getting the solder onto the right pads in the right volume during SMT rework of high pin count or very small footprint SMT devices. The most common types of solder deposition include printing, dispensing, and hand soldering. Each of these methods has pros and cons, depending on a variety of factors in the rework process.

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Knocking Down the Bone Pile: BGA and PCB Warpage—What to Do

07-10-2019

Warpage of BGA packages or PCBs can occur when any heating and subsequent cooling cycle is gone through. This may leave the package to bow in the middle. Pushing the corners up or downward will show up in bridging (caught on X-ray) or cause opens that would show up on endoscopic or visual inspection. Here's what you need to do.

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Knocking Down the Bone Pile: Straightening Out Those Corners

05-22-2019

A PCB can be dropped, dinged, or mishandled as it is placed into a board carrier in the PCB assembly operations area. When the laminated material is damaged in this manner, can it be repaired? The answer, like most engineering answers, is that it depends. Read on.

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Inspection of BGAs After Rework

03-21-2019

After removing and replacing a ball grid array (BGA), the acceptability of the interconnection of the solder balls to the PCB should be assured, because this assurance and the criteria for that assurance are the customer’s outgoing inspection criteria.

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How Much is Too Much?

01-09-2019

One of the typical questions process engineers pose regarding the PCB rework process is, "How many heat cycles are too much?" Asked in another way, the question is, "How would one define a limit on the number of times a PCB can be reworked while still being reasonably assured that the reliability has not been impacted based on its operational environment?" Find out how.

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2018

Proper Thermal Shielding Yields Highest Rework Results

11-21-2018

There are numerous "gotchas" if the rework technician does not care for components and materials neighboring the component rework area. However, careful planning, shielding, and sometimes removing a neighboring device or material will ensure the highest possible rework yield.

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Filling the Gap: Underfill Rework

09-21-2018

Rework technicians must take into account a variety of factors when considering whether or not to rework underfilled components, such as BGAs, CSPs, flip chips, and other component packages on handheld devices. But without a full understanding of the underfill characteristics, expect the outcome to be low yields unless the board was designed with reworkability in mind.

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Replating of Gold Fingers: Getting the Shine Back

07-30-2018

There are several instances where the gold contacts on PCBs need to be replated, and IPC A-610 discusses several of these cases. This column by Bob Wettermann discusses gold replating of defective contacts caused by processes such as wave or selective soldering, or plating.

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Masking of Conformal Coating During Assembly and Rework

06-11-2018

Masking of printed circuit boards post rework/repair as well as for initial PCB assembly is often required if the PCB is to be conformal coated. If a board that has conformal coating on it needs to be reworked or repaired, the conformal coating needs to first be removed before the operation of rework or repair can take place. This article centers around the various options for conformal coating masking via a liquid application process.

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Device 'Dead Bugging'

04-20-2018

"Dead bug" attachment of electronic components is a way of building functioning electronic circuits by soldering the parts directly together or by soldering miniature jumper wires between the component leads and the PCB lands instead of the traditional surface mount or through-hole soldering of components onto a PCB.

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PCB Pad Repair Techniques

01-08-2018

There are a variety of reasons behind pads getting "lifted" completely or partially from the laminate of a PCB. Per the just revised IPC-A-610 Revision G, a defect for all three classes occurs when the land is lifted up one or more pad thicknesses. Lifted pads can occur when a device has been improperly removed or there is a manufacturing defect in the board construction. In any case, as with any repair, the ultimate decision on the ability to repair the pad lies with the customer.

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