What is a baseline profile?

Baseline profiles are used purely for set-up purposes. They are manually-fed into the reflow oven and are run in tandem with a monitoring system in order to create what is called a “virtual profile.”   Baseline profiles, thus, become the standard by which all automated profiles are compared.  If there are any deviations between the baseline profile and the automated profile, this information is recorded and can trigger alarms and stop production temporarily. Baseline profiles also have the added advantage of becoming a true “gold standard” for all of your profiles, since the same profiling board is not being used repeatedly or subject to degradation of the PCB, thermocouples or operator error.

The set-up of a baseline profile is performed by running a normal profile, per recipe.  Meanwhile, 1-2 fixed mounted probes (typical an array of 15-30 thermocouples) collect their own set of data as the PCB runs the length of the Reflow oven with a profiler. This information is then compared and processed by the monitoring system.  This array of internally-mounted thermocouples is able to reconstruct a virtual model of a profile. When a production board enters, without the profiler, the same TC readings that were present when your oven was profiled are now re-mapped onto each and every PCB.

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Comments

  1. Glad to see you are looking objectively at your process. You point out a notable issue with production ovens. There is a difference between a “loaded” oven vs. an “unloaded” oven. Generally, the process specification will allow for fully loading an oven and still produce products within specification. In some cases, the PWI will improve when an oven is fully loaded, and drift to the outer limits of the specification when unloaded. I favor an oven setup that behaves in this manner. Most oven recipes can be developed to function in this manner. Taking the extra steps to achieve this balance in the oven recipe is worth the extra effort.

    We have had requests for a software solution that will adjust oven set points according to the thermal load of the oven and respond to the various changing conditions. Currently, this option is not available with the KIC 24-7 software, or any of the KIC products.

    However, the KIC 24-7 software will monitor your oven and issue an alarm when the conditions drift out of specification. KIC offers a software solution called “Navigator” which is available for KIC 24-7 and KIC 2000 monitoring and profiling systems. Navigator is a prediction software product that uses the database of the Profile Library, that is part of the KIC 24-7 monitoring system and KIC 2000 Profiler. Navigator may be used before the oven becomes out of specification and allows you to create set points that are in specification if your oven is loaded or unloaded. Currently, changing the set points requires that another baseline profile be ran to verify the set points are still within specification.

    If enough customers request an interest in a product that adjusts set points “on the fly”, KIC would look into this request. Currently, many customer processes do not allow for KIC products to make changes in this manner.

    Thanks for your post Miguel. Hope this covers your question.

  2. Miguel A. Colomer says:

    Do KIC fix measurement fluctuation when the oven was completely full and later empty? For manufacturers that cannot stop production this system is fantastic. Also, a good tool to identify problems with the oven zones when the thermal slopes are monitored.

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