Posts Tagged Thermal Profiler

MOLE Talk

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.

So why take the risk of being yet another abuser of the “Car Talk” theme? Well because I have been asked this question many times: “Why did you call it a Mole?” Call what a Mole?

You know the M.O.L.E. ® Thermal Profiler, that pocket sized 6-channel temperature measurement logger used to see if you are getting the right temperature to your solder joints without overheating your thermally sensitive components (J-STD-075) in reflow or wave soldering machines.

There is a mouth full! Well, to answer this question I thought I’d take a look at the many really cool things a Mole can be. Here are a few:

A Mole of any substance shall have the same number of atoms, molecules, ions, or other elementary units, as the number of atoms in 12 grams of carbon. That number is: 6.0225 × 10^23, AKA: Avogadro’s number. So if you want to calibrate your scale, simply pile up 602,250,000,000,000,000,000,000 atoms of carbon and you’ll have 12.001 grams.

An annual celebration of the date and time represented by the numbers 6.02×10^23 or October 23 from 6:02 a.m. to 6:02 p.m. There is a cool web site in honor of this important number in the world of chemistry and physics. Check it out.

A small gray burrowing mammal, that is for the most part blind, although they probably can tell night from day. Moles tunnel through dirt and eat small worms living mostly underground. Moles can be found in most parts of North America, Asia, and Europe, although there are no moles in Ireland.
What do you call a Mole’s baby? Yes, a Pup. A female Mole is called a sow and the male is called a boar. And if you have more than one Mole you have a “company” of Moles.

A benign skin tumor found on human skin appearing as a small, sometimes raised area, with darker pigment.

A Mexican sauce made from chili peppers, other spices, and chocolate. However, it’s pronounced “Mole-Ay” and I often take service calls from Spanish speaking customers who say they have a “Mole-ay” that is due for calibration. I recommend this dish at your favorite Mexican restaurant. However, there are many different ways to make it so if you don’t like it at one restaurant, don’t be afraid to try it again at another.

A spy who has worked their way into an organization or country for the purpose of getting information. Wasn’t there a TV show?

A pier, jetty, or junction between places separated by water. I did not know this could be called a Mole until today.

A complete line of stage and production lighting products made by the Mole-Richardson Co I’m into theatrical lighting so naturally I’d know about this one.

OK, so this has been fun. Can we get on and just answer the question, “Why did you call it a MOLE?” Taking from the best parts of the many uses of the word Mole, we grabbed the following:

  1. A Mole crawls through tunnels.
  2. A Mole secretly spies on the goings-on of something or someone without detection
  3. A Mole of something is a number that starts with the number 6 (6.02…)
  4. A Mole is a delicious Mexican sauce. OK, we took nothing from this possible definition of Mole.

Put these together and you get an instrument that goes through the dark tunnels of many different thermal processes, measures the temperature of that process without disturbing it, and does it in 6 (or 3, or 20, since the original naming of the brand) locations of that process. Only a M.O.L.E. ® can do that. So that is why we called it a Mole. So what does the acronym M.O.L.E. stand for?

M = Multichannel – more than one temperature measurement input

O = Occurrent – events that happen (or occur) at the same time

L = Logger – a recording instrument

E = Evaluator – one who makes a judgment, as in the “OK” button on the new V-M.O.L.E. and MEGAM.O.L.E.

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“Wavy” Reflow Profiles

Profile temperature measurements that cycle up and down

Profile temperature measurements that cycle up and down

Why are some profiles more wavy than others?

 Wavy looking profiles may be caused by something not always expected. In this case we were reflow soldering a very large and thick board; a back plane board that was 14 inches wide and 30 inches long and over 0.25 inches thick. One would expect that a board of this mass would heat very slowly and with a somewhat smoother temperature profile graph.

The cycling up and down of the profile temperature, especially in the area between oven zones, was in this case caused by the boards large thickness. The surface of the board was quickly heated by the oven’s convection. Where that convection rate is lower, such as between air jet holes and between zones, the inner core of the board, which is not yet as hot as the surface due to the boards low thermal conductivity, pulls the surface temperature down toward the core temperature. Then as the boards moves into a new zone or under a convection air hole, the surface temperature is again pushed back up to a higher temperature, creating the wavy up and down look to the profile. It’s important to remember that the thermal profile of very thick boards, depending on their internal thermal conductivity, may behave like this as they are reflow soldered, even though common sense may say they should have a much smoother profile look.

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