ECD M.O.L.E.® Thermal Profiling - Article

Thermocouple Insulation Type There are many kinds of insulation used over thermocouple wire. Here are a few of the most popular, and their advantages and disadvantages...

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.

Here is one possible cause to check on before you apply the failure to the component.

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.

Attaching thermocouples in Vapor Phase Soldering (VPS) presents a potential problem that’s often overlooked. To illustrate this potential problem, let’s look at how VPS works. All the work needed to heat the components and solder joints to the melting temperature of the solder take place in the very thin “condensate” layer of liquefied vapor phase fluid. This 0.2 mm layer is very much like the layer of water that forms on a cold drink on a humid summer day. (See figure 1.) The vaporized fluid (cloud) is at or very near the boiling temperature of the fluid, which is typically 200ºC to 240ºC, depending on the fluid you choose to use.

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.

Calibration of electronic measurement instruments is a necessary process, even though most electronic equipment is very stable and somewhat “resistant” to the effects of environment and changes due to aging.

Yes I know, I’m ripping off the Car Talk radio program name, the truly funny call-n show where two well educated brothers have the best of fun giving advise (correct for the most part) to their call-in victims about everything from car repairs to personal relationships. If you’ve not heard the program, find your local NPR radio station and check it out. And also, I’m following on the heels of Board Talk, a web based collection of questions and answers by two respected members of the electronic assembly community who do a nice job (in a “Car Talk” like format) of answering many common questions submitted by followers of the Circuitmart web based electronic assembly resource.

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:

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 M.O.L.E. a reality, because now the MOLE profiler can automatically compare the measured temperature profile to your pre-programmed profile requirements.

Gage Repeatability and Reproducibility (GR&R) studies are designed to show the amount of variation certain portions of the measurement system contribute to the total variation in measurement, often expressed in percent. There are many ways and products available to help you calculate these numbers, which range from a piece of graph paper to full blown software packages costing 1000s of dollars.