Assertion: spindle's speed | /r/HasProperty | 70 sfpm
Facets:
value: in order to maintain the same tool life
type: PURPOSE
Source sentences:
text: If a material has a machinability rating of 70%, it can be determined, with the above knowns, that in order to maintain the same tool life (60 minutes), the cutting speed must be 70 sfpm (assuming the same tooling is used).