This issue happen ,because the lubrication pump was damaged before for a long time and no alarm on machine ,until customer notice some noise coming out .
So HSM already WA-claim for the new lubrication pump. But customer request for checking all the ballscrew as well.
HSM already check all the axis ( X Y Z ), and found that only the Y-axis was damaged.Burning mark and jerking happen at the middle of ballscrew. The 30 um. is the error by touch dial on ball trace and moving along Y-axis.
So HSM issued the WA-claim for this completely Y-axis ballscrew and bearing.