Archive for category Reflow Profiling
Unusual Component Lead Contamination
Posted by Paul Austen in M.O.L.E. MAP, Reflow Profiling, Thermal Profiler, Thermal Profiling on August 26th, 2011
Today’s blog post originally appeared in Circuitnet on August 22, 2011
http://www.circuitnet.com/articles/article_83073.shtml as a response to an Ask the Expert Question. We think it’s worth repeating here as well.
Subj: Unusual Component Lead Contamination
We suspect the issue visible on the attached image is due to contamination on this component lead. We only see this issue on one component type, and only on one side of the component.
Can you offer any comments? E.W.
REPLY FROM PAUL AUSTEN, OF ECD:
Here is one possible cause to check on before you apply the failure to the component.
As with most solder quality problems, it is best to make sure the solder thermal profile, as required for good soldering for you specific solder paste, is being met. Do not assume that a general thermal profile for this board is the same everywhere on the board.
Make sure the thermal profile on or very near each end of this component is as needed. I have heard of components as small as this stand up on one end and then lay back down again during the solder transition into the liquid state (AKA: liquidous, or liquidus) because one end of the part heated faster than the other by a few fractions of a second. By the time the component lays down again, it is too late for best wetting.
To look for this possible time delay in the heating of the component’s ends with your thermal profiling software, make sure the profile peak alignment tool in the profiling software is turned off so you can see instant by instant the temperatures measured at each end of the part through the liquidous point of the solder. If one end is hotter than the other during this time, this may be part of the problem.
The cause of the temperature difference may be because one end of the part was on a pad that had no (or poor) thermal relief compared to the other. Typically, you need both pads of a component to be thermally equivalent. It may be that the board design needs to changed, or it may be as simple as running the board through the oven process turned 90 or 180 degrees to the current orientation.
However, turning the board 90 to 180 degrees may introduce other production or thermal issues on other components. None the less it may be worth trying.
Paul Austen, Senior Project Engineer
Electronic Controls Design Inc
paul.austen@ecd.com
Paul Austen is a 30 year veteran Senior Project Engineer with ECD in Milwaukie, Oregon. Paul has seen and worked with the electronic manufacturing industry from many points of view, including: technician, designer, manufacture, and customer.
What’s New – July: M.O.L.E.® MAP 2.20a Release
Posted by Ray Pearce in M.O.L.E. MAP, Ray's Blog, Reflow Profiling, Thermal Profiler, Thermal Profiling on July 29th, 2011
Since the advent of the CPU, electronic products have been getting “smart.” And now, to the extent that software and an internet connection make it possible, even appliances which most of us would consider to be a block of steel and plastic with a singular function, such as a refrigerator, are now capable of keeping inventory, reminding you to go shopping – even placing delivery orders to restock! Yes, when you really think about it, it’s often the software that enables and drives product innovation and answers the question “What if we could….?” The latest ECD software is a perfect example. It allows us to give our profiling equipment the very capabilities that customers have had on their wish lists. A M.O.L.E.® can’t order you lunch, but here’s “What’s New.”
This month ECD announced availability of the new 2.20a version of M.O.L.E.® MAP software. Introduced in 2007, MAP (Machine-Assembly-Process) received multiple innovation awards, and is now the software platform for ECD’s entire line of thermal profilers: SuperM.O.L.E.® Gold 2, MEGAM.O.L.E.® 20, V-M.O.L.E.®, SuperM.O.L.E.®, Gold and PTP® VP-8
This version release coincides with the new SuperM.O.L.E.® Gold 2 availability and implements inputs from our Software Advisory Board (yes, we have one!) So without further ado, here are the top 5 new features and benefits of M.O.L.E.® MAP 2.20a.
- AutoPlay
This new feature auto-detects your M.O.L.E.® type and quickly links your plugged-in M.O.L.E.® to perform these basic tasks:
- View the status of your M.O.L.E.®
- Setup your M.O.L.E.® to perform a data run
- Download your most recently recorded data
- Start M.O.L.E.® MAP
This instant USB access eases the learning curve for the novice and focuses the operator on the basic profiling tasks at hand, shielding them from the full feature set of the software.
- Improved Navigation
When you do open MAP, the “Welcome” screen now displays links to recently used Directories and recently viewed Profiles. Quickly resume your previous work session by clicking where you left off with this convenient new feature.
- Bulk Import of Previous M.O.L.E.® Files
Speaking of Profiles, you will probably want to import your libraries of SuperM.O.L.E.® Gold profiles (from SMGSPC) into MAP, which converts the .mdm file into the new .xmg format.
This MAP version implements group importation of existing .mdm and collaborative .xmg profile data. With a simple click-shift and drag, you can now move the contents of old Workbooks (an SMGSPC term) into new Directories, M.O.L.E.® MAP’s term for the currently viewed data in the Spreadsheet Tab.
- PDF Printing to File and Email
Another way to collaborate your process engineering work between EMS/OEM is to provide documents to operators in PDF format. The new MAP integrates PDF printing with an improved Print Selection dialog to accomplish portrait or landscape orientation directly to Email or a File. Great when your customer demands hardcopy proof!
- Free Self-Serve Web Authorization and Automatic Upgrade Notification
Last but not least, licensing fees and pay authorization have been replaced with free “Self-Authorization” through the ECD website. We give you a 31-day window to go to the Help menu, select “Authorize” then click on “Web Authorize”. After you fill out the web form and agree to standard terms, our site sends you an email with your software unlock key.
It’s as simple as that! Plus, you will be notified of new releases in the future. We always want you to have the advantages of our current release. Thank you for reading this month’s What’s New!
Free MAP 2.20a download is available at ECD DOWNLOADS. (Check out the Readme file for the entire list of Rev 2.20a M.O.L.E.® MAP improvements!)
Till next time,
Ray Pearce
ECD Sales Engineer
ray.pearce@ecd.com
Heat Flow Happens
Posted by Paul Austen in M.O.L.E. MAP, OvenCHECKER, OvenRIDER, Profiling, Reflow Oven Verification, Reflow Profiling, Thermal Musings, Thermal Profiling on May 24th, 2011
An often misunderstood concept is heat flow and how it can influence the temperature of the product being heated so here is Wikipedia’s definition of heat flow, followed by a discussion of our own on the subject.
Energy needs a conductor in order to flow
1) An energy difference between two objects.
and
2) There is a conductor to act as a bridge enabling the energy to flow.
Energy always flows through a conductor from an object of high energy to an object of low energy. In this illustration, the high-energy object is a moving hammer, the low energy object is the table and the conductor is a block sitting on the table.
When you hit the block with the hammer, the energy contained in the moving hammer is transferred to the block when it hits. Some is also conducted through the block and transferred to the table it is sitting on. However, because the block is not a perfect conductor, which is true for most things, some of the energy stays in block. That energy bounces between the molecules of the block like balls on a pool table.
Because the molecules rub up against each other, and there is friction between them, some of the moving energy of the hammer is converted to heat energy, which causes a rise in the block’s temperature. It all comes down to molecular motion in an imperfect conductor creating friction that raises its temperature. Therefore, temperature increase is a way of observing energy flow, and energy flow that causes a temperature rise is called heat flow. Read the rest of this entry »
Total Heat – Another way to analyze your thermal profile
Posted by Paul Austen in Extracting Parameters, M.O.L.E. MAP, Reading Profiles, Reflow Profiling, Thermal Profiling on January 21st, 2011
One of the most popular ways to determine if a thermal profile of an electronic assembly is within specification is to consider the limits placed on four measurements or parameters: Initial Ramp Slope, Soak time, Time Above Liquidus and Peak temperature. Keep these four parameters within the specified (solder paste) limits and you can be assured that you are soldering the parts without damaging them.
Figure 1 Typical thermal profile with the four traditional parameters within spec
There are other ways to look at a profile which can be helpful in determining if the profile may threaten components and showing if it is consistent, both across solder joints, and over time.
In the profile example above, the Time Above Liquidus (TAL)on solder joints 1 and 3 are within 2 seconds, yet channel 3 (from the data; plot not shown for visual clarity) had more readings at higher temperatures. This means that although this part may have the same time above 183ºC, more readings were at temperatures higher than channel 1; higher risk of damage. Also note that the peak temperatures were not far apart; 222.2ºC vs. 223.5ºC.
So we added a new measurement to the MAP software to not only show Time Above Liquidus, but also consider the temperature values during the TAL portion of the profile. This new measurement has several names: “Total Heat,” ” Area Under the Curve,” or “Stress Integral.” It combines the time element of Time Above Liquidus with the temperature measurements during that time to give the Total Heat the component experienced, expressed in degree-seconds.
Figure 2 Total Heat measurements (component 1 only shown for clarity)
In this case, even though the Time Above Liquidus values are within 2 seconds and the peak temperature is less than 2 degrees apart, the Total Heat values are 2278º-sec and 2628 º-sec which differ by 350 º-sec! This clearly points out that component 3 had to withstand more Total Heat than component 1 and this simple parameter can now be examined in an instant, using the latest; version 2.18j of MAP software.
The Cooling Zone
Posted by Paul Austen in Profiling, Reflow Profiling, Thermal Profiling, Wave Solder Profiling on November 18th, 2010
A sometimes forgotten fact about reflow and wave soldering is that anywhere from 25% to 50% of the time a solder joint spends above its melting temperature, aka: time above liquidus (TAL), takes place in the “cooling zone”. Much time is spent getting the heating portion of the oven recipe finely tuned to produce a robust thermal profile, only to toss the product, covered with liquefied solder into a cooling zone where the solder joints must return to a solid state. The rate at which this occurs (cooling slope) is even more critical using lead- free solders. Giving the cooling zone some well deserved attention when defining the requirements of the thermal profile is essential to a good Thermal Quality Management program for your soldering process.
The cooling zone is where the quality of the solder joint is defined, with the cooling slope influencing the joint strength, and overall longevity. These two qualities are often at odds with each other because strength often comes from slower cooling rates, while longevity results from faster rates. Different cooling slopes have been tested to try to find what rate produces the best combination of strength and long life when subjected to accelerated thermal-cycling. These studies have concluded that slow cooling rates (1 to 2 °C/sec) allow too much time for intermetallic alloy growth, a strong but often brittle alloy prone to cracking when stressed. Faster cooling (5 to 7 ºC/sec) can form a softer solder joint with less overall strength, not to mention possible component damage. Cooling slopes between 3 and 4 °C/sec were found to be the best at producing a solder joint with both good strength and overall longevity.
So… don’t forget the cooling zone when developing the best thermal profile for your solder process.
References:
“Cooling Rates in Lead-free and Tin/lead Reflow”
SMT Magazine
by Denis Barbini, PhD.; Ursula Marquez
“Accelerated Thermal Fatigue of Lead-Free Solder Joints as a Function of Reflow Cooling Rate” Journal of Electronic Materials
by Qi Y; Zbrzezny A R; Agia M; Lam R; Et al
“Proceedings of 2005 International Conference on…” Asian Green Electronics
by Qiang Hu; Zhong-suo Lee; Zhi-li Zhao; Da-le Lee
On Reflow Soldering
Posted by Paul Austen in Reflow Profiling, Thermal Profiling on May 3rd, 2010
You know, at ECD we have been in the thermal profiling business for over 25 years. Most of what we profile is the reflow soldering process. There are many others like wave soldering, baking, drying, curing, and a host of other industrial temperature process. Still, reflow soldering is the most popular use for a thermal profiler like the MOLE. And yet, most of what can be found on the subject of reflow soldering, at least on the web, focuses on specific portions of the reflow process and not on the entire process as a whole.
For example, component manufacturers would have you avoid certain limits in temperature or temperature change rate (slope) to avoid damaging their parts. And that’s ok, but that only tells you what to avoid, temperature wise. Most solder paste manufacturers would have you believe that their paste can take most any reflow thermal process so as not to be excluded from purchase. This too is understandable and in reality, most solder pastes are good and will solder your components to your circuit board. Many standards (like IPC standards) on the subject suggest what your product MUST withstand to be considered robust and not necessarily an ideal reflow process thermal profile. This makes sense, because there is no one reflow thermal profile that will solder every possible circuit board assembly, and standards must be general in their application. Then there are the public websites that are often peppered with bias toward a specific brand of profiler in their description of what’s important or how to view it.
Each year new talent enters the work force and training in the art of reflow soldering is limited or costly. Worse yet, some learning about the reflow process only occurs from failures caused by incorrect reflow process settings. And perhaps worst of all, many reflow solder machine are still running the same setting set generations ago because no one currently available has the skill to make them better. Just because many industry veterans understand the issues around reflow soldering and thermal profiling does not mean the new talent can hit the road running. And, since most every electronic assembly will pass through either reflow soldering, wave soldering, or sometimes both, I thought it important to take a look at the reflow solder process, dissect it and consider what’s important to measure and control. Click here for the more in-depth look.
Diverse Needs, Diverse Solutions – We’ve got an App for That!
Posted by Paul Austen in M.O.L.E. MAP, MegaRIDER, OvenCHECKER, OvenRIDER, Reflow Profiling, Thermal Profiling on March 29th, 2010
How many different MOLE profilers and Test Pallets does it take to monitor a reflow solder machine? It depends on who you are and why you are monitoring it? We just want to make sure there are as many tools as there are reasons for running a thermal profile. Here are a few good reasons:
1. “I’m from the Metrology lab and it’s time for the annual calibration of your reflow oven.” We’ve got an app for that. After you’ve finished with the oven’s calibration procedure, you can run the MegaRIDER-20 with a Process Test Pallet to see if the machine is uniform across the conveyor width and has the same heating capacity as it did the last calibration or maintenance.
2. “I’m the Manufacturing Engineer and our QC Department wants me to show that this oven is in control.” We’ve got an app for that. You probably need more information than the once a year Metrology profile can provide. So weekly you can an OvenRIDER and see that every zone in the oven is performing the same using X-Bar R charts to prove it.
3. “I’m on the New Product introduction team and I need a good recipe to solder a new board without killing the parts.” We’ve got an app for that. The Super M.O.L.E.® Gold thermal profiler will let you connect T/Cs to the board to see exactly what’s going on, thermally, on the areas where you and the designer have the most concern. Use the Prediction tools in the new MAP software to lock in the perfect recipe.
4. “I’m a Line Technician and I have to know my reflow oven is ready to run product without all the wires and circuit board stuff.” We’ve got an app for that. OvenCHECKER is one pallet loaded with the most powerful profiler on the market today. It takes no more time to run than the first production board and it lets you know if the reflow oven is ready or not. No downloading, no comparing numbers on a chart, just Go, or No-Go.
The Fastest Way to Know Your profile is “OK”
Posted by Paul Austen in Extracting Parameters, M.O.L.E. MAP, Reading Profiles, Reflow Profiling, Thermal Profiler, Thermal Profiling on February 25th, 2010
Now there is a way to verify that your profile requirements are being met in less time than you ever thought possible. The letters in the name M.O.L.E.® thermal profiler have always stood for Multi-channel Occurrent Logger Evaluator. Now the patented* “OK button” feature truly makes “E” in MOLE a reality, because now the MOLE profiler can automatically compare the measured temperature profile to your pre-programmed profile requirements.
The ECD V-MOLE with patented one button “OK” profile evaluation
(The OK Button is also available on the 20-channel MEGAM.O.L.E.™ thermal profiler, and OvenCHECKER™ )
Taking only seconds, the MOLE can tell you and your oven operators if the profile just measured is in or out of specification with the universally understood Green for good (GO!) or Red for bad (STOP!).
You get to set the specification limits for any or all of the four most popular profile parameters:
- Ramp Slope
- Time Between temperatures
- Time above Liquidous
- Peak Temperature
…and you can choose which of the MOLE’s input channels to include, up to 20 channels on the MEGAM.O.L.E.™, and three on the V-M.O.L.E.™ thermal profilers.
The Specification Table in MAP Software
Using the MAP™ Profiling software, enter your specification limits for the four profile parameters in the Upper and Lower Limits table in the “Target-10 OK” tab. These values will automatically be sent to the MOLE profiler when you use the Verify Process Wizard to confirm that a previously characterized oven recipe is still performing within specification.
MAP™ Profiling Software Target-10 OK Profile tab
Once programmed, the MOLE profiler can be used many times (up to 96 times) to Verify your oven is producing the same profile, without reconnecting to your computer. Simply run the profile and press the “OK Button” on the MOLE. No more running back to the PC software to download to see the results. One push of the OK button, and you get your answer…Go, or No-Go. It’s that simple!
*U.S. Patent Number 7653502.
Why do an Oven HealthCHECK™? Why Calibrate Instruments?
Posted by Paul Austen in Reflow Oven Verification, Reflow Profiling, Thermal Profiling on January 27th, 2010
Why do an Oven HealthCHECK™? Why Calibrate Instruments?
You might ask, why should I perform an Oven HealthCHECK? In other words, why should I run a rather sophisticated measurement system through my oven to produce a rather nice looking 3-D plot of the cross belt temperature uniformity?
Figure 1: An example 3-D plot of the oven with very good cross belt uniformity, < 3ºC
I may not like the answer because I might find out my oven has a problem that I cannot fix? Sounds like a “head in the sand” sort of excuse to me.
I would ask a different question: “Why do you calibrate your bench test instruments?” Is it to find out that the instrument is out of spec? Heavens no!! That would be a nightmare because it would call into question everything that instrument was used to test since the last time it was calibrated. So why do you calibrate if the results could be so disastrous? Simple, it allows you to show and document that the instrument is and always has been “within specification.” So when the auditor asks, how do know your instruments are in calibration, you pull out the Certificates of Calibration.
Figure: What’s the first thing you check after you receive your Certificates of Calibration? The “As Received: Within Tolerance”
ECD’s Oven HealthCHECK is designed to certify and document your oven’s performance or health. It is a “calibration” done on a regular interval, say once a year, to show that the oven performance is within specification and not changing over time. It can also provide a baseline level of performance around which you can compare into the future. Further, if you have several ovens, the HealthCHECK can show you which ovens are best for applications where oven uniformity is critical.
Back this up with much simpler and more frequent verification profiles of your oven using OvenRIDER or OvenCHECKER, where simple software-generated Xbar-R control charts show daily indications of a thermal process that is “in control,” and you will no longer have to steer the auditor around your reflow oven. You can proudly show that you know your oven’s performance level and that it is consistent because you have taken the steps to measure your oven’s health as part of your Thermal Quality Management program. Such a program should be marketed, since it shows you commitment to understanding your oven’s thermal nature and you have the data to show it. This sure beats the “head in the sand” quality program which may characterize your competition.
Thermally Sensitive Components and J-STD-075
Posted by Rex Breunsbach in Profiling, Reflow Profiling on March 26th, 2009
Good solder joints are not enough. A good reflow profile must consider component temperature limitations.
The new IPC standard released Dec 08, Classification of Non-IC Electronic Components for Assembly Processes, J-STD-075, calls for thermal classification of components, and recommends a marking system to help contract manufactures recognize component temperature limits during the soldering process. Failures don’t show up during initial test, but much later on in the product’s life – often six months to two years later, and well below forecasts that drive pricing and warranty policies. ALL parts have temperature limits; and until we take the time to profile the process to which we subject these parts, we can’t know if we cause harm or not.
ECD has moved in that direction with our Thermal Quality Management (ThQM™) Program. We think this will give the industry the knowledge and tools to look at ALL components in the comprehensive light necessary. Equally important, it introduces a program and method of dialog between OEM and EMS provider on soldering process issues.
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