When troubleshooting a problem which is unique to a particular tool, but not present in a sister tool, then the solution lies in locating the differences.
Issue: Company is encountering an unexpected reduction in part dimensions after conditioning where a growth in dimensions has been seen in all similar parts. The parts which are similar and produce expected dimensions are molded in 'sister molds' (term used for mold which is nearly identical in design and is molding parts of similar design). These parts have an expected dimensional growth across the entire part after conditioning.
Problem Solving Technique: The solution to such a situation lies not in the new part alone, but in what differentiates the new system from the existing parts which produce expected results. This process involves comparing the new part, mold, process, & material until the difference is found. In theory two similar systems should produce similar results. If they do not, you need to find the differences whether it is a hotter core, reduced melt temperature, larger gate diameter, or a lower material drier residence time. Once the differences are found, you can evaluate and test each to determine whether it is causing the unexpected result. For example, if a core is warmer, add an additional temperature controller to that cooling zone to reduce the temperature and determine if that causes a more expected result... Isolating and testing each potential cause is critical to determining the cause of a problem and its ultimate resolution.