Frequency to verify the reflow profile

How many times have you found that your oven was performing differently? this will give you the answer on frequency. We have a dedicated board and profile that we use to verify the oven operation. We perform this every 3 mos. and I believe that this frequency is uneccesary. What I have found is that when an oven loses a heater/blower/whatever that the oven goes into alarm and then we fix it. I have yet to see an oven wait for your verification to fail. so daily actually is the best way to ensure that at least at that time of day it is running fine and hopefully nothing will change for 24 hrs. I would recommend that you use some other kind of material that will withstand these multiple cycles and develop a profile for it and then check it to that as often as you like. If the oven is working you only need to check one profile and you can be assured that all of your other recipes will perfrom as they should. You can also just run your profiler without a board and record the temps and just compare on a daily basis.

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We do both our ovens once a week. If something looks out of tolerance (we've developed acceptable tolderances based on many recorded profiles over time and oven mfg. specs.) we wait a couple hours and try again. The recorded data over time is very handy if you need to pop the hood and mess with blowers, wiring, etc. Most times, the oven comes back in after the first out of tolerance profile. Anyhow, in my opinion, once a week is more than enough and don't try to fix your oven unless you get out of tolerance data after a number of iterations over a couple days.

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We have enough history to know that frequent profiles are a waste of time. We check the profile once a month, after any significant maintenance, and after a changeover. Other than that we rely on the alarms on the individual zones.

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Both our Quad ZCR and our Conceptronic HVN-102 ovens have had blowers out with no alarms raised. We knew there were problems based on how boards were soldering, but don't count on your oven to tell you if anything is wrong with it. We verify once a month, and after maintenance.

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After profiling with a scrap board of the product I'm profiling, I would immediately send the MOLE through with one thermocouple only, no board, to provide a standard that I could reproduce without depending on scrap boards. I used that setup before every production run, and only used the scrap boards after maintenance or if we saw soldering problems.

The nice thing about a thermocouple in air is that it responds immediately to any changes and shows problems (dead blowers, dead elements) right away.

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QS and ISO can really play a part here. If so, the best way I found was to run parallel T-couple ports to the thermocouples of the oven. Now you can run a board and gather all your thermal information and set your temps. Now use parallel ports to verify your actual oven temps showing match a hand held calibrated thermocouple. Nothing beats a boards attached to a Slim Kic, but if you need to verify your oven daily or weekly, this is a good way to approach it. Mounting all the parallel jacks close to the display makes life a lot easier too.

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