Profiling Dual Lane Variable Speed Reflow Ovens

Profiling a Dual Lane Reflow Oven

Dual Lane Reflow Oven Application Note


Dual lane or multiple lane ovens are not new, what is new is a trend to vary the speed of each individual lane. On face this is a brilliant idea, you can run more than one production board down the same oven at the same time.  Problem though with most manufacturers already challenged as it is with developing a robust profile on a single lane oven you are just adding an incredible about of complexity, right?

Fred Dimock of BTU authors an excellent paper in the March Issue of Circuits Assembly, titled “Practical Thermal Profile Expectations in a Dual-Lane, Dual-Speed Reflow Oven – Developing a recipe that with satisfy both boards.”

The key to developing an oven recipe is by using intelligent prediction tools such as the KIC Navigator and a methodology outlined by the same company KIC in an application paper titled, “Optimizing the Recipes in a Dual Lane/Dual Speed Reflow Oven Using the KIC2000 Software with KIC Navigator.”

Dimock in his study concludes:

With a little understanding and work, a process engineer can develop the data to help find a recipe that will allow them to establish the set points and belt speeds for dual-lane dual-speed reflow ovens. It can be done in multiple runs with actual belt speed changes or as few as two runs by using predictive software. It will also help determine the extreme cases where the boards are too different to be run on a dual-lane dual-speed oven. In all cases, the engineer needs to confirm the results by profiling the actual boards at the belt speeds they determined would be best. The great lesson is that after the first profiles are optimized on the reflow oven, much of the remainder of the work can be done at the engineer’s desk without tying up the production equipment.

To read the full article click here.


Tips on Cooking Both a Perfect Thanksgiving Turkey and a PCB

Why does it take half a day to cook a Thanksgiving turkey?  The answer is simple ― you have 20 lb of bird that simply cannot just be nuked in a microwave like last night’s dinner.  If not properly thawed, prepared and monitored, you either have an overcooked, dried-out bird or worse: Salmonella. Strangely enough, as you will see in a moment, PCBs are not that much different.

Let’s say you skip the thawing process and in your haste stick a frozen bird in the oven.  What happens?  The bird may look properly cooked on the outside, but as soon as you try your skill with the carving knife, you either hit bedrock or the inside is completely raw. OK, I will admit I speak from personal experience on this one (please do not bring this up with my wife).  Are PCBs any different?  Well, your reflow profile has a preheat phase, with the purpose of bringing your PCB to temperature. In other words, the entire mass of the board with all its components is gradually brought to equilibrium. If you do not do this, you run the risk of thermally shocking your components when they hit reflow and peak.  Thawing your bird and preheating your PCB ― you have the same objective in mind.

So, for the vast majority of us, we really have no idea when the turkey is fully cooked until getting an internal reading. A PCB is no different. On the surface, both might look great, but upon closer inspection, you discover some components have defects due to improper reflow or, for that matter, when you cut into a turkey that is still pink it really hits home that you aren’t cooking a TV dinner.


Because of this, as we all know, a 20 lb turkey requires a thermometer. I will concede that some of you use the old “poke the bird and check for pink until done” trick. Let’s assume you are not as skilled, like me, for example. Would you seriously cook a turkey by relying solely on the oven’s temperature reading on your stovetop?  Of course not, but why do some of you profile your PCB by relying on your reflow oven’s reported readings? Are either situation that much different?  Actually, yes. Your nice self-contained turkey cooking oven is more of a steady state, but there remains a large difference between what is reported by the oven and the internal temperature of your turkey. In contrast, your PCB is exposed to anything but a steady state environment because it rides on a conveyor through different heated zones with blowers, extraction systems and both ends of the oven even open to the elements!  For this reason, any oven manufacturer will adamantly tell you to profile and with regularity. Alright, you may have learned how to cook a turkey in your Mama’s kitchen and, in fact, be skilled at not using a thermometer; however, I doubt any serious SMT manufacturer would take a similar approach, checking your PCBs regularly for “doneness” in your reflow process.

What about placing the fate of your Thanksgiving feast on the cheap-o plastic pop-up indicator that likely came with the turkey? Do not laugh. How many of us use the trailing wires that came with the reflow oven?  Now to be fair, both work in principal; otherwise, you would have the likes of Purdue Farms with food poisoning lawsuits on their hands, but they only give you ballpark readings in many cases. By design, the turkey is going to be a little overdone and dried out.  Your PCB, on the other hand, cannot afford to be a little overdone or it is simply OUT of spec.  You can get by with eating the overcooked turkey … the gravy and mashed potatoes are there to make up for less than a perfectly cooked bird. But your PCB will not be as forgiving.  Trailing wires, never mind being cumbersome to use, have a tendency to kink and stretch, which compromise their readings.  They also are susceptible to 50 or 60 cycle noise from some reflow oven environments, further questioning their accuracy in some cases.

So you want to cook the perfect bird. Who doesn’t? So you pony up for a stainless steel large-dial meat thermometer to accurately read the internal temperature of your 20 lb bird. You also pony up for a KIC Explorer with Navigator because you want to create the perfect deep-in spec reflow profile. It will not only tell you the specific temperature of the joints of your $500 BGAs, but it also will find a balance that does not overcook them or any of your other temperature-sensitive components on the PCB.  No pop-up indicator profiler needs to apply since the KIC Explorer with Navigator will go the extra mile and tell you not only if you are in-spec but how DEEP in-spec your profile is, along with what can you do to improve the profile in minutes, if not seconds.  Now do you know of any turkey thermometers that can do that?

So when you prepare your Thanksgiving turkey, and as you pause to give thanks, consider applying the same care and consideration that you have given to your family’s feast as you do to your PCBs.

Happy Thanksgiving – Profilingguru


2011 Profiling Guide

The popular Profiling Guide is back with this second edition. I’ve added a new section on profiling for Wave with the help of two solder wave gurus Mike Young of Aligned Solutions and Dave Nixon of Ayrshire Electronics. Also a contributor is Ed Briggs of Indium who provides profiling solutions to common reflow defects such as voiding, tombstoning and solder balling. What you will certainly find particularly interesting about Ed’s work is he gives you real life examples on how you can modify your oven recipe to reduce or eliminate defects!

Also in this edition, I continue to work on what I started in the first edition the Six Sigma’s DMAIC approach to profiling. I’ve added Analyze and Control to Define-Measure-Analyze-Improve and Control. Being able to analyze and control your process are becoming the difference between whether or not a Contract Manufacturer secures a new customer (or keeps one) and a cornerstone to Black Belt manufacturing for OEMs.

You can pick and choose what is important from this guide, I purposely organized it to be read in segments and not necessarily from cover to cover. For example, perhaps a full DMAIC approach to profiling is too much to ask? You are struggling just to Define and Measure your process, am I right? Let’s face it, the majority of SMT and Wave processes worldwide are not even profiled and those that are profiled fail to go beyond the basics. Don’t feel bad, this guide will help you. You are not alone, the vast majority of process engineers still don’t realize how simple it is to improve their process. I made sure this guide helps to explain in a no nonsense easy to read fashion how this is possible, no theory, no boring one hour long technical seminars, no academic discussion, but what do I need to do to get actionable results.

Lastly, I wrap up the book with a chapter on Advanced Profiling Methodology. I focus in particular on non-destructive methods which even the novice can appreciate and implement. Included in the book you will find tools for creating offsets for components like BGAs, where drilling holes into your PCB for profiling I promise will become a thing of the past. I provide references to real science and free tools are even included. Furthermore, “virtual profiles” and other viable options to sacrificing an instrumented PCB are explored.

Just like last time I had a great time pulling this book together. I leave and breathe profiling and certainly no offense if you don’t share my passion. At the very least, I hope you have just as much fun reading it.

– Profiling Guru


Man versus Forno de Refusão

Thiago Oliveira da Placibras da Amazônia em Manaus, foi o vencedor do jogo Homen versus Desafio do KIC

IPad Winner

“Na minha opinião o KIC é o melhor traçador de perfil do mercado, o software navigator é fácil de usar e muito simples, além de tornar nosso trabalho fácil e rápido. I gosto do KIC e do software navigator.”  – Thiago Oliveira.

A todos os participantes o nosso muito obrigado pela participação lembrando que os participantes tem direito ao upgrade do KIC Power que tem validade até o dia 30/04/2011.

KIC Man versus Forno de Refusão

Concorrência de Execução de Perfil.


Se você conseguir bater o Software KIC Navigator estará concocorrendo um iPad.

Faça o download do jogo atravé deste link : Download Game and Instructions e participe.

Todos os participantes que enviarem uma solução, independente de está correta ou não receberão gratuitamente, mas por tempo determinado um certificado que dará direito a um upgrade KIC Navigator Power *** no valor de US$ 975,00.

*** É necessário que o cliente tenha instalado o KIC Navigator ou Auto-Focus para funcionar o KIC Navigator Power. Certificado do Kic Navigator Power é válido até 30 de Abril de 2011.

Há três desafios neste jogo real que se tornam progressivamente mais difícil de resolver:

1. Corrigir o tempo de refusão acima para o tempo de um perfil básico.
2. Converter um perfil de estanho-chumbo para sem chumbo.
3. Balancear um perfil de que contem alta massa na PCI e baixo volume ou massa de componentes.

Cada um desses três desafios representam uma PCI real. Em todos os três desafios esteja certo que o KIC Navigator encontrará uma solução dentro das especificações em menos de 15 segundos. Você pode fazer isso?

Além disso, cada solução o perfil de refusão será refeito com as alterações sugeridas para mostrar o quão preciso é o software KIC Navigator.

Regras Básicas

Após fazer o download do jogo e das instruções deste jogo, os participantes devem apresentar as soluções de perfil de refusão usando o software KIC 2000 para todos os três desafios até 10 de dezembro enviando estas através do e-mail

Os participantes devem fazer um perfil de forma melhor que o software Navigator em todos os três desafios.

Os valores corretos do desafio de acordo com o Software Navigator serão colocados no site até 13 de dezembro.

Apenas uma apresentação, por participante será aceita. Não há limite de tempo ou limite para o número de tentativas que um participante pode fazer antes da apresentação dos seus resultados.

Se houver empate, os finalistas serão escolhidos em um sorteio para o iPAD a ser realizado em 15/12/2010.

Não há limite para o número de participantes de cada empresa. A concorrência está disponível apenas para cidadãos brasileiros ou naturalizados e que sejam usuários ou que tenham adquirdo equipamentos Slim KIC 2000, KIC Explorer ou qulaquer outro equipamento fornecido pela KIC.

Não poderão participar desta promoção, colaboradores da KIC, representantes, ex-representantes e colaboradores de empresas representantes da KIC no Brasil.


Spot Checking your Reflow Oven – Part I

Reflow ovens have come a long way, they are much more stable, better controlled, well built and less expensive.   Nevertheless, the need for profiling has not been eliminated, since after all the reflow oven is just a means to an end.  You still need to dial in your oven set points to achieve a desired profile and what oven set point temperatures you choose is not what you see on your PCB.  You may be surprised how many line operators worldwide do not make this connection!

Once you have developed numerous profile recipes, many of you would only like to spot check the reflow oven to see if there has been any change.  The logic goes, if I have developed robust profiles and I can check my oven periodically to confirm there hasn’t been any change, I can therefore infer that my profiles are still valid?  Well, yes and no.   “Infer” is the action word here that can lead to trouble if you are not careful.   Let me give you an example.

For fun I ran some popular oven verification tools you can find on the market to see if they could catch changes that I knew would throw my profiles out-of-spec.   What I did first was to profile an actual PCB, followed by my oven verification fixture.   Running the fixture soon after my profiles gives me a baseline to compare against for future spot checks.  I then took a small clip on desk fan and blew into the entrance of my oven tunnel, knowing that it would change the thermal dynamics inside my process.   I made sure my fan was low enough not to trigger an oven alarm, but just enough airflow that based on my experience would in fact change the process environment inside my oven.

Here is what I found.   My profiled board width was ~12″ wide so a sizable mass.  I used a fixture of the same width, since changing my belt width is not practical.  When I ran the fixture I was given oven statistics to compare against my future spot check.  No problem so far.  When I ran the fixture a second time (fan a blowing), I found a 1 degree delta change.  Now I think you would agree 1 degree doesn’t seem like much at all.   Of course I am not looking at a profile, rather machine data so here is that word, I “inferred” that my process was still fine.   Wouldn’t you?  Now intuitively, I knew this fan blowing up the tunnel of my oven is creating process changes perhaps more than 1 degree.  So how do you know, well you run a profile!   Sure enough when I ran a profile, I did not see any longer just a  1 degree delta.  In fact my profile was out of spec.

So what happen?  I can only assume the fixture which I was using that weighed in at close to 7 lbs, must be absorbing some of the changes inside the oven, masking what is really going on.  Keep in mind the fixture is not designed to profile, rather it is designed to detect  measurable change to my process that would impact my profile.   The mass itself must be factoring into my ability to detect change.  Again this is just my observations and my conclusions are subjective, but I can say that it did not capture what is the whole point of this exercise.   So I guess the mass of your vehicle is important and it is not all just relative.  Any thoughts out there, please post your comments.

Well I guess it is back to profiling, or is it?  Stay tuned for part II as I explore other options.