First, congratulations on becoming [more] involved in this fascinating area.
>One, has anyone else ever experienced and dealt with a company debate regarding whether or not your reflow ovens should or should not be calibrated?
Sure, it�s an excellent debating topic. We argue about stuff like this all the time. See, somebody�ll be stewin� about something and they�ll go out and root-out some meaningless piece of trivia, and then table it in a meeting with a agenda that has about as much pertinence to the new topic as dirt. [Although, we have argued about dirt, also.]
So, everyone rolls their eyes toward the heavens and prays that the meeting chair ignores the stewer and moves on to close the meeting, giving us the slimmest of chances that we can get some �work� done today, but that rarely happens. So, then we get assigned to another task team, which seals our fate that we never get anything done in the shop during normal working hours.
>And two, does anyone have an opinion on the need for oven calibration if you are using profiling equipment that is calibrated by an outside source?
Where�s the deal � * ISO9000, 4.11.1 has words like you must "...establish and maintain documented procedures to control, calibrate, and maintain inspection, measuring and test equipment used...to demonstrate the conformance of product to specified requirements." This indicates that you only need to calibrate equipment that you use for inspection and test. * Then 4.11.2 b that tells us we must "identify all inspection, measuring, and test equipment that can affect product quality, and calibrate and adjust them..." So, this brings process control equipment into the scope, in addition to inspection and test.
Here's the difference. There is a distinction made between Inspection, Measuring, and Test Equipment [IM&TE] that is specifically used for demonstrating conformance (including conformance to internal requirements, such as process variables), and IM&TE used when demonstration of conformance is not required.
In the first case, documented procedures are required. In the second case, it's not so clear.
For instruments that are not used to demonstrate conformance, many companies label them 'for reference only' when conformance is demonstrated later in the process. Whether this is permissible, and whether it is a good idea, is situation-dependent and I can't generalize. Often, all that is called for is an 'operational check' rather than a full, traceable calibration.
Philip Stein�s [ pstein@measurement.com ] rule of thumb is pretty simple [he says] and he has restated it many times. He says: * If trust in the value that results from a measurement is important, calibrate it whether you think calibration is required or not. * If you don't need to trust the value, why are you making the measurement at all? (This is not a rhetorical question, sometimes you do need some sort of reference number but the actual value isn't all that important, but you should always ask the questions.)
We record a profile as an oven first piece on each lot that is included in the work package. So, we calibrate. But, I could see checking a recipe [maybe on a flow line], recording the data on a chart, and living happily ever after. For us, it came down to �How often are you changing the recipe?�
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