Thank you all for the professional answer.I also contact the KissSoft consultant,and get similar answer.attached is some infor mation from them,(not a complete file).we design a set of gear train,and confused what kind of plastic material will be choosed,so we care the wear saftey,I have a limit kisssoft licence,the 'wear along the tooth flank'can not be generate.in the define material window active the wear factor,but the data base were not define for wear calc.How to evaluate 'Safety against wear',>1 is ok?