The purpose of the mold certification is to ensure the mold is built according to specification before the mold validation procedures begin, e.g., critical dimensions on the first mold set are cut "Steel Safe", core/cavity stack up dimensions are correct, cavity to cavity spacing is correct, cooling circuit layout, etc. The tool builder is required to provide verification of all critical metal tolerances on core and cavity ‘fits’ to be +/- 0,005 mm. The critical part dimension metal tolerances must be less than 10% of the plastics part dimension tolerances. In many cases, it will be necessary to go tighter than 10%. The mold certification should be performed at the tool builder while the mold is being fabricated to expedite any needed adjustments to the mold. Mold certification needs to be agreed upon when the mold order is placed. A copy of the mold certification should be included with the final mold validation report.