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Solder Pot Maintenance and Dross Removal

Question: We found an article online about solder pot maintenance and the removal of dross, specifically there is an interest to us in the “changing bar solder” Section. Does turning up the solder pot too high cause impurities to collect on parts? Can you comment on this?

What’s with the expiration dates on solder paste or wire?

Question: We all have from time to time had solder, be it in paste or wire form, sitting on shelves for what seems like years. I know there are all types of variables related to its’ longevity, but given this, what’s really going on with the expiration dates and are there tests you can perform to validate or extend this period?

Accept or Reject: Solder Contacting Component Bodies

Question: We are having a discussion about whether or not solder can touch a component body; in particular, we have a plastic SMT component where the solder has wicked up to the body on the legs. Sections are shown below. Is this condition acceptable under any circumstances, or is it always a reject in all three classes?

Issues of Burnt Flux on Class 3 PCB Assemblies

Question: I have always had in the back of my head that burnt flux is a defect for all class 3 assemblies. Upon further review I have not been able to identify the specific section of the IPC-A-610F standard which identifies burnt flux as an acceptable or defect condition.

Gold Removal Issues with Hollow Cup Connectors

Question: We are having a hard time with the removal of gold from hollow cup connectors. Using lead free solder, we are wicking the solder out with braid, but what is happening is that the pins are getting overheated and coming loose from the connector. Are there other methods we could explore?

Acceptability of Conformal Coating Bubbles

Question: We have some PCB cards that are flooded with champagne size encapsulated bubbles. While no single bubble bridges between conductors there are numerous small bubbles similar to Figure 10-131 below, None have popped, as they are all encapsulated. Is Figure 10-131 a Defect Photo?

SolderTips: Avoiding the Creation of Splices Via Wire Twisting

Question: The IPC lists different splices for wires including wrap, hook, mesh, and lap. We have all seen wires spliced together by twisting the two wires together forming a gentle twist before soldering. This splice would not have the physical strength of a wrap or hook splice, but it seems like it would offer at least the same strength as a lap splice with less aggravation, since the splice would stay in place during the soldering process. Why does the IPC not recommend creating this type of splice?

SolderTips: Solderability Issues with Nickle Plated Surfaces

Question: We are working with components with leads of tin/lead over nickel. After the manufacturing processes, some of the pins are exhibiting what appears to be flaking plating, leaving behind unsolderable surfaces. They will re-tin with flux, but reappear following steam-aging. Is this something you have encountered before?

SolderTips: Gold Removal and Wave Soldering vs Hand Soldering

Question: Regarding gold removal requirement under Section 4.5.1 of J-STD-001, it allows: “A double tinning process or dynamic solder wave may be used for gold removal prior to mounting the component on the assembly”…

SolderTips: Soldering With Butane Soldering Irons

Question: Can Butane solder irons be used for soldering coax cable (pin on center conductor) or any other type of cabling? We are concerned about the temperature as compared to regular soldering stations.

SolderTips: Issues With Incomplete Solder Reflow in Production

Question: We have some PCB assemblies that show incomplete solder flow due to signs of flux exhaustion.

SolderTips: Printed Circuit Board Bow and Twist Showing Up

Question: We have recently started to see board flexing in one of our circuit board assemblies. This assembly has a 40mm PoP BGA component on it with an integrated heat sink.

SolderTips: Issues With Incomplete Solder Reflow in Production

Question: We have some PCB assemblies that show incomplete solder flow due to signs of flux exhaustion.

SolderTips: Soldering Iron Calibration – Do You Really Have To?

Question: To calibrate or not to calibrate, that is the question. We just purchased new soldering stations and were told that they do not require calibration. While we think that all tooling requires some calibration over time, what am I required to do?

Rechecking Thermal Profiles

Question: Is it necessary to replicate the thermal profiling process during long term mass production of products?

Solder Paste Shelf Life and Testing

Question: We have some solder paste that has been in a sealed box at 4 degree Celsius for more than 8 months. The shelf life is 6 months. Can it be used without an issues?

SMT Component Shifting

Question: We have a problem with chip components shifting during the reflow process, which is being detected during automatic optical inspection. The shifting is not limited to a single component, but rather changes daily, where the component shifting occurs and moves from one location to another very randomly.

SolderTips: How Long Should it Take to Create a Solder Joint

Question: Are you aware of any time studies or standards that have been developed to determine the amount of time it should take to create a solder joint while hand soldering, either a through-hole, or surface mount component?

SolderTips: Problems With Stress Cracks in Ceramic Components

Question: We are having a problem with ceramic SMT components (CAPS) showing stress patterns and cracking after thermal testing. Have you ever seen this and if so, what is allowed or acceptable according to IPC standards, even with the lack of verified electrical failure of these components?

SolderTips: Dealing with the Problems of Soldering Iron Tips Breaking Down

Question: We are having a problem with soldering tips oxidizing and becoming unusable after a few hours use. We are using a lead-free organic rosin core solder and apply additional liquid rosin flux when soldering fine pitch components. We are running the soldering irons between 750 and 800 F.

SolderTips: Defining Shear Forces for Surface Mounted Components

Question: Is there an IPC or other specification that exists explaining the minimum shear force requirements for surface mounted components?

SolderTip #49: Calibration of Soldering Irons

Question: We have both steady output temperature and temperature variable soldering irons. There has always been a long-standing question as to whether we needed to calibrate these irons to meet certain ISO requirements. Is there any documentation that indicates how we should handle this? Answer: This is an interesting question with several variables to consider.

SolderTip #48: The Cleanliness of Wire and Terminal Connections

Question:  What are the specifics on wire and terminal connection cleanliness requirements and how do they compare to PCB cleanliness? Answer:  Cleaning wire and terminal connections is somewhat different than cleaning PCBs along with cleanliness and measurement testing techniques. Boards and assemblies are cleaned of flux residues for a variety of reasons, dendritic growth on

SolderTip #47: How Long Does it Take to Make A Solder Joint?

Question:  I have heard so many conflicting answers as to how many seconds it takes to make a solder joint. Can you tell me why it may take 1, 2, or 3 seconds to make a solder joint? Answer:  A solder joint is a metallurgical process; to make a sound solder joint there has to

SolderTip #46: Open Connections Found on BGA Components

Question:  We have been stumped by occasional opens at the corner balls of some BGA components after reflow. We have experimented with many minor adjustments, yet this occasional problem continues. Do you have any suggestions? Answer: Based upon the warp and twist characteristics of the printed board laminate materials and the BGA, this could be a

SolderTip #45: Manual Soldering vs Wave Soldering

Question:  We assemble simple through hole circuit boards. What are the main factors to consider when shifting from hand soldering to wave soldering? What factors should be used to justify continuing to hand solder vs. switching to wave soldering? Answer: Manual soldering is a very unique process with many variables and people being one of them.

SolderTip #44: IPC Guidelines for Flux Selection and Use

Question:  Does the IPC have guidelines or recommendations on flux selection and use? Answer: You ask a very interesting question regarding the selection of flux or fluxes and whether or not IPC provides information or dictates where certain fluxes can and cannot be used.  The answer is NO, IPC will not provide information as to which

SolderTip #43: IPC J-STD-001 Rev. E Instructor Training Materials

Question:  We have been conducting operator training for both J-STD-001 and IPC-A-610 to the Revision D documents. Can you tell me when the training materials will be available for Revision E and if I have to retrain everyone to the new revision? Answer:  There are really two parts to address this question, one is the

SolderTip #42: Request for EPTAC Webinar Topics

Question:  Do you have a topic or issue you would like us to discuss in an upcoming webinar? Answer:  If the answer is yes, then we need you to send us an email. For the past three years of webinars, yes, three years, EPTAC has been delivering webinars based on our experience in working with

SolderTip #41: J-STD-001 Revision E is Here – Order it Now!

Question:  When will the new revisions for the IPC-A-610 and J-STD-001 documents be available? Answer:  J-STD-001E is now available. IPC-A-610E will be available in April, really sometime soon. J-STD-001E is recognized worldwide as the sole industry-consensus standard covering soldering materials and processes. This revision includes support for lead free manufacturing, in addition to easier to

SolderTip #40: Component Mounting and Acceptability

Question:  We have a switch that gets wave soldered during the assembly process, but it does not always stay flush with the printed circuit board. Is there a specification that describes how to measure flushness or what the acceptability requirements are for this type of part? Possible Solution:  The final criterion for any component is

SolderTip #39: Class 2 vs Class 3 Assemblies

Question:  Can you give me a basic definition of the differences between Class 2 and Class 3 products and where these differences show up in the IPC documents? Possible Solution:  Class 2 products are defined as products where continued performance and extended life are required and for which uninterrupted service is desired, but not critical.

SolderTip #38: Clean vs No-Clean Fluxes

Question:  We are using a Kester 186 RMA Flux for our assembly process. Can you tell me if you have to clean an RMA flux and what the issues are if we do not? Possible Solution:  You don’t have to clean an RMA Flux. The flux hardens and can be left on. The problem most

SolderTip #37: Through Hole Soldering of Thick PCBs

Question:  We are attempting to hand solder through hole components in a very thick board, but are finding that the solder does not flow through to the other side of the board.  Is there a method or technique I need to use to accomplish this? Possible Solution:  Manual soldering of thick boards is a very

SolderTip #36: Wave Soldering Insufficient Fill and Voids in PTH

There are many reasons for insufficient fill of a PTH (Plated Through Hole) and the occurrence of voids in barrels.  Board thickness, finished hole size, board plating material, flux type and application method and type of solder all affect this possible defect.  Let’s look at these two problems and a few possible reasons for them.