The design of high cycle fatigue structures as typically seen in
the plastics molding industry may not immediately seem apparent. However,
with the increased needs of high volume part productions and decreased mold
cycle time, the molding pressures on thin walled deep parts
becomes a high cycle fatigue concern. The cost associated to premature fatigue
failure typically results in unplanned and unexpected costs to the molding
company. The utility of engineering fatigue calculations for mold
core design was implemented to complete detailed comparison between
two alternate designs involving 1-gate or 3-gate designs. The detailed issues
of vent and retaining pin locations and geometry features was combined with
details of the core manufacture. The original design knowledge
of the mold cores was shown to exist, and for what reasons, and was not
reduced or changed in the list of additional design recommendations. The
engineering fatigue evaluation involved MoldFlow calculations as
provided from the clients analysis team with methodologies provided by Quigley
Scientific. The fatigue calculations used a full range of strength reduction
factors applicable to this industry and illustrated the management of these
factors, hence manufacturability, would increase mold core durability. The
reliability of the fatigue predictions was computed to be consistent with
the internal product quality standard.