The aim of this study was to optimize gear tooth flank modification in a compound planetary
reducer with a reduction ratio of 100:1 to achieve uniform load distribution and minimize the face load factor
(KHβ). To achieve this, a prototype of the compound planetary reducer was designed and manufactured, and
tests were conducted under temperature-controlled, unlubricated conditions to induce wear on gear tooth
surfaces. Microscopic image observations confirmed edge contact on the gear tooth surfaces. Based on these
observations, a digital mock-up (DMU) simulation model was developed and validated to align with the
experimental results. A parametric analysis of lead slope change was performed using the validated model
to determine the optimal value. After optimizing the lead slope, crowning modification was applied to shift
the load distribution toward the center of the tooth flank. Comparison of the gear face load factor (KHβ)
showed that applying the modifications improved load imbalance by up to 83.45%, effectively solving the
edge contact problem compared to the results without modification. The combined approach of testing under
unlubricated conditions and validating the DMU model through both experimental and analytical methods
resulted in highly reliable findings, offering valuable insights into improving the performance and durability
of compound planetary reducers.