Setting up your Solder Spec

Many profiling software packages will have a pre-loaded library of solder specs. You should still refer to the solder paste manufacturer’s data sheet to confirm accuracy, but these libraries are becoming ever more accurate and robust. Providers, such as KIC, offer regular updates online for download.


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Solder Paste Library from KIC® 2000 software.

Once you input your solder paste spec, you can use the default setting or further refine your solder spec to reflect limitations to component temperatures and change other parameters as well.

solderpastepeak

You can further refine any of your paste specs to compensate for component tolerances and other inputs specific to your process.

For example, your paste may allow a certain maximum peak temperature, but knowing that one of your components cannot tolerate such a high temperature, you can manually change a peak of 245°C to the component’s tolerance of 243°C.

Many profiling software packages also allow you to define specific segments of your profile.  You may, for example, have more than one rising slope.

solderpasteinputs

Many inputs can be defined for your profile.

Lastly, you may need to define component or density-specific regions of your PCB.  You might first define a general profile for the entire PCB and then pull out focused areas on the PCB with tighter or expanded specs.  For example, you may need to tighten your temperature tolerance for ceramic packages. Tighten the specs around a troubled area, while loosening them elsewhere.  After all, your goal is to produce a PCB in spec.  Some profiling software packages can help you target these areas, even TC-specific.

solderpastetcs

Each TC can have its own individual spec, which is common when you have a component which high heat tolerance issues.

You can eliminate wasted time and effort by simply running “what if” scenarios.  In the case of PWI-driven software, a single value is assigned to your user-defined inputs that indicates if a process and/or component are within spec. By tracking these PWI values alone, instead of trying to interpret hundreds of data points, a multi-variant statistical relationship is created for all inputs. A single value, or PWI, is outputted. The bottom line is that you will get your process within spec, with the least amount of effort!

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