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Have a technical question? Dealing with a process or standards issue and not sure where to turn? *Helena and Leo, our technical experts are here to help.  Just fill out the form below and they will review and answer selected questions as soon as they can.

*Please Note: We may post your question on our site for educational purposes, so that others may learn in the process. All references, both personally, professional and relative to product details will be removed from the discussion.

Soldering Covers to a Housing

Question: We are soldering a cover to a housing and I was not able to find any quality criteria for the amount of solder flowing down the inside of the housing wall. We are hand soldering the lid in place on the cover, filling the seam between the housing and cover with solder. At times we use SN 96 and other times SN 63 solder depending on how the customer will future process the units. Are there any guidelines for this process?

IPC/WHMA-A-620 – Definition of “visible”

Question: I am interested in knowing if there’s a definition for the word “visible” as used in IPC/WHMA-A-620 where some target criteria states “visible”, does this mean unaided?

What is the Correct Way to Fill Solder Cups

Question: I noticed a lot of my techs, while soldering cups, are not putting the soldering iron on the back of the cup, filling with solder, then adding the tinned wire. They will tin the wire, set the wire in, press the iron on the wire/solder cup and add solder. I’m not too familiar with soldering cups, but I am thinking that this will cause solder to wick up into the jacket. Is this a fair assumption?

Addressing Missing PCB Pads From Soldering Rework

Question: We have a class 3 product that has some missing pads, that were removed during a rework process. If I epoxy the component in place, does the product still meet with class 3 requirements?

Solder Selection for Printed Circuit Boards and Terminals

Question: I know for tinning stranded wires you should not use Type H or M flux, so we are ordering a No-clean solder Sn63Pb37 with a flux designator ROL0. My question is, would you use that ROL0 solder on the entire solder termination when you solder it into a cup or terminal, or use a higher level solder such as ROMI? My second question is what kind of solder would you suggest for doing repair or adding a component to a surface mount board?

IPC J-STD-001: 5.1.3 Question on Wire Tinning

Question: 5.1.3 States that wires must be tinned if soldered to boards with some exceptions. My question is if the stranded wire is individually tinned wire, not “topcoat” or bare copper, does this count? Would it need to be dipped in a solder pot (tinned) before soldering in a through hole?

SMT Polyphenylene Sulfide (PPS) Film Capacitors and Defects

Question: Are there any specifications referencing Polyphenylene Sulfide (PPS) film capacitors and horizontal lifts on sides (or cracks) when heated like ceramic chips if cracked horizontal, or is it considered a defect for all three classes?

Addressing Circular Mil Area (CMA) Buildup

Question: We work in cable assemblies and had a question about Circular Mil Area (CMA) buildup. We find ourselves frequently building up our conductors when using a crimp style contact, using the Rule of 3’s (28 AWG folded in half would be 25 AWG). What is the rule when it comes to a solder style contact that is using a conductor smaller than the contact, for example, a 12 AWG contact using a 16 AWG wire? Is buildup required or does the solder fill make a good enough connection?

Soldering Aluminum Wire

Question: I am performing some modifications to a Raspberry Pi circuit board for a university research group and I was asked to substitute a USB cable for the stock, on-board USB port. I’m having difficulties soldering the braided shield to the board. It appears that the braided shield may be made of aluminum. The braid simply will not accept the solder. No wetting, whatsoever, even after cleaning and fluxing. Are there any special techniques for soldering aluminum wire?

Will I Damage a Wire-In-Board if it is Bent Too Far

Question: I am an IPC Certified J-STD-001 Instructor. We solder our wires straight up from the via, then bend them to where we need them to go. We had some assemblies built outside and they tinned and bent them at a right angle, then soldered them into the printed circuit board. My question is, can I just move these wires (cold, not reheat) to the position we want and not damage the wire in the area of the solder joint?

Dip Tinning Conductors with Low Temperature Insulation and Solder Pot Contamination

Question: We have an application that due to the type of stranded conductor being used, it may be necessary to semi-strip the insulation, flux and dip the conductor with the insulation slug still in place to prevent the conductor from fraying or birdcaging.

IPC-A-610 vs J-STD-001 and What Does What

Question: I just wanted to ask a quick question. I’ve always believed that IPC-610 was an inspection of PCB assemblies and J-STD-001 was the actual operation of soldering. Is this correct?

Reliability of Reworked Lead-free Assemblies

Question: Our current soldering process for a product proceeds like the following: two heat excursions, thru reflow, two thru a wave and one thru rework. How many more rework cycles can we do before compromising the reliability of the assemblies?

63/37 Versus Lead-free Solder

Question: What type of impact would it have if the wires were tin-dipped in lead-free solder then were soldered to a board with 63/37 solder? Are there problems that may occur that would cause difficulty in soldering?

Conductor Strand Damage in IPC-A-610 Rev E

Question: Section 6.3.2 on strand damage is confusing in the new Rev E document. Note 3 under the table seems to define damage as anything greater than 10% of the cross sectional area of a strand. This is difficult to explain or visualize on the production floor. The IPC-A-610 Rev D document did not include Note 3 and seemed to define strand damage as a strand with exposed basis metal. The Rev D document seemed to be easy to understand. Am I interpretting this correctly, and is there a good way to explain strand damge per the Rev E document?

Solder Defect/Non-Conformity Listing for IPC-A-610

Question: Is there a comprehensive Excel listing of the non-conformities shown in IPC-A-610? (Just a list of defects) This would be used to make a defect tracking database.

Bridging Two Adjacent Pins on an IC

Question: Can we bridge two adjacent pins on an IC using bare wire across those two pins? What specification do we reference for the acceptance of the rework performed?

Gullwing Lead Deformation

Question: Does the IPC impose limits, or publish a standard on the amount of 160 CPLD lead bending that’s acceptable before restoring to original specifications?

J-STD-001 3.2.2 Solder Purity Maintenance

Question: We build components, and we would like to get your suggestion on which max limit column to follow. I am thinking Assembly Max Contaminant, due to the fact that we strip and tin, and solder connections to our components. We are not using our pots to solder the components to the board. Would that be the correct category to follow for us?

Looking for a New Hot Air Rework System

Question: We are looking for a hot air rework system. Nothing fancy… just something that will help us to remove parts during rework. We currently have an OK Industries system MTR 4000 series with accessories. This works very well with what we need to accomplish.

IPC 620 Compliance of Poke Home – Junction Box

Question: There is a product called Poke Home – Junction Box with the URL to a specification sheet at:

Soldering Iron Tip Maintenance

Question: Hello, I would like to know the benefits of tip tinning and tip maintenance. Is it necessary to tin and turn off irons when not in use?

Spacing of Radial Components Off a Printed Circuit Board

Question: What is the spacing requirements between the board and the bottom edge of the component that doesn’t have a spacer or insulator in a supported through-hole terminations?

Wave Solder Machine Flux System Testing on a Budget

Question: If you were to begin performng tests to better understand you Wave Solder Machine’s Flux System capabilities and you had a limited amount of resources (both human and capitial resources), in what order of priority would you perform the following tests and why? [Flux Weight (% Solids), Airflow (Velocity), Airflow (Uniformity)]

Solder Tip Flooding to Remove Leaded Solder

Question: Is it true we can use lead-free solder to remove leaded solder on our soldering iron tips? I seem to remember we were shown how to flood the tip with lead-free solder three times, wiping clean after each flooding, to remove any lead residue before soldering a lead-free solder joint.

When is an IPC/WHMA-A-620B Errata Due Out

Question: Some time ago my company ran into issues with erratas that were added to our IPC-A-610 manuals. An ISO auditor did not like that we were adding notes to our standards. Lots of questions were asked (can you guarantee all updates are the same, this ink smears, have all operators in the factory been trained to the updates, are all of your customers aware of the changes, etc. etc. etc.). My company really doesn’t want to buy the IPC/WHMA-A-620B non-errata books. Is there any indication when the books including erratas will come out?

To – From Wire Labeling Specifications and Requirements

Question: Can you please tell me if there is a specification regarding labeling, and the information that should be included on the label? I am specifically talking about cabinet wiring, labeling each end with To and From locations to assist in troubleshooting, or for people in the field from removing and replacing wires incorrectly. All I can find is that it is up to the manufacturer unless it is UL wiring.

Wet Sponge Cleaning vs. Dry Brass Sponge Cleaning

Question: Is “wet sponge” solder tip cleaning mandatory for leaded and RoHs soldering? Are there any downfalls to only using the dry “copper sponges”?

The Difference Between Touch-up, Rework and Repair

Question: What is the difference between touch-up, rework and repair?

Darkened SMT Capacitor or Resistor Terminations After LeadFree Soldering Reflow

strong>Question: Lately some of our terminations on SMT caps and resistors look dark, almost purple, like they have been overheated during the reflow process in a lead free environment. According to everything (e.g.,.Data Sheets, mole profiles, oven temps), we are not overheating any of these components. I am wondering if anyone else has had this particular condition occur?

Gold Removal on Bottom Only SMT RF Components

Question: We have some RF components that are “bottom only” and the castellations are gold. Is there anything we can do about the 75% gold removal rule?

SMT Components During Reflow Float Off Pads

Question: We install D-Paks on a number of boards (8.3.14 in IPC-A-610). These parts have a tendency to float during reflow. We have done quite a bit of process work to minimize the floating, but parts do still occasionally float and are difficult to rework because of the thermal plane. Where we get into trouble is when the part floats straight back and the heel of the gull wing leads are no longer on pad.

Review Questions for IPC-A-610E

Question: Are there review questions for Rev. E that we can use as handouts?

Charring of Wire Insulation

Question: We have an ongoing debate regarding the charring of wire insulation. IPC-A-610E is very clear on the topic. Aside from overheating damage to the PCB, what other dangers does this pose? Do you have any white papers on the topic? Thank you for the help.

Allowable PCB Etch Repair

Question: We received a PCB with 3 etches connected together that were not supposed to be. Is there anyway to repair these and if so, is it compliant to IPC 610 or JSTD 001? We do know how to repair these issues, but our inspector is requiring documentation as to the acceptability of this process. Can you help with this?

When to Tin and Not Tin Wires

Question: I have a connector that you insert a 7/30 wire into and hold it in place by tightening a screw. Should the wire be tinned? I have look in my IPC 620 standard and the only reference I see is Section 4.4, indicating that stranded wires should not be tinned when “wires will be used in threaded fasteners”. Not sure if this applies. Is this true?

Excess Flux Causing Intermittent Connection Issues

Question: We are having an issue with the cleanliness of flux. The excess no-clean flux is located in an Ethernet port connector. The units pass all tests with no issues, however; we have recently had a couple of field returns where it was indicated that the units were having intermittent connections. We have made a decision to remove all flux from the hand soldering operation and inspect all finish goods. IPC-A-610 Section 10.4 is very vague about this issue. Can you comment on this?

J-STD-001E-2010: 4.5.1, Gold Removal Issues

Question: Since we are seeing more and more components with gold finish on the solder attachment pads(specifically, leadless ICs mostly with bottom side terminations only for RF circuitry), how would you propose we meet the J-STD requirement for gold removal?

Multiple Wash Steps Affecting Resistance Characteristics

Question: We have a customer that believes that multiple wash steps is the cause of 0805 resistor failures. They claim that it is devaluing the part. I have never heard of this issue. Could you shed some light on this?

PCB Markings – Missing Silk Screening

Question: We have some panels of 6 PCBs each, double sided, which were built on our pick and place machine. After the panels were built, it was discovered that a couple panels do not have the silk screening for the component locations on one side of the board. Per IPC 10.5.3, it appears these are a defect(scrap), but it does not affect our end use form, fit, or function and we hate to scrap product without a good reason. Is this possible?

Ionic Residue Value Conversion from Metric to English

Question: Per J-STD-001D, paragraph, Static Extraction Method, the contamination shall be less than 1.56 micrograms/cm². What is the amount of allowable contamination per inches squared?

Soldering Iron Tip Temperature

Question: What is the thumb rule for soldering iron temperature for RoHS & Non-RoHS manual soldering? Answer: Thanks for the question regarding solder iron temperature selection for manual soldering operations. There are two factors involved in making this selection, one being the mass of the metal being joined and second the size of the soldering

IPC CIS Training Reporting

Question: I just recently provided the CIS on the IPC-A-620 standard within my organization and the training was very fun. All the documentation provided in the trainer kit is very helpful. After the course, I sent the report of application specialist training to [email protected], but I never received a confirmation back. My question is, should I expect a confirmation from the IPC or I can print the CIS certificates?

Hardware Installation for Tooth Washer

Question: What is the proper hardware installation on a mounting hole when a tooth washer is used?

Post Lead Trimming Reflow Requirements

Question: I’m having trouble discerning the requirements for post lead trimming reflow in the new version of IPC-A-610. It seems to indicate only “leads must be covered by solder”. Can you elaborate on where I may find more conclusive instructions in the 610 to share with operators?

IPC-A-620 Flag Label Secifications

Question: I have a question about flag labels. Under IPC standards, is it ok if the label moves on the wire, or harness? In the IPC-A-620 standard, it doesn’t say a lot about flag labels, and my quality inspectors are divided on whether it is ok for the label to move on the wire.

Soldering Thick PCB’s With 3 oz Copper

Question: How do I get a flow through on a 120 thick pcb with 3 oz copper layers. I saw your soldering tip #37. We have tried multiple applications but with no consistent success. Is there a special iron to use?

Silver Immersion Finish Boards

Question: We have a customer requesting us to use Silver Immersion Finish boards that are at least 5 years old. We have no idea how the boards have been stored during the last 5 years, seeing they have been stored at our customer’s facility.

Cutting Solder Joints (not during lead trimming)

Question: Is it acceptable to “shave” or cut solder joints?

Bottom Termination Parts

Question: I have a bowed part on a bottom terminated part, and I’m trying to find the specification on such a part. Do you know the bow specification of IPC 7093, section 5.2.6 on max warp this part should be?