CNC – Modifying cutting speed for required tool life
Recommended cutting speeds in tool catalogs are for a tool life of 15 minutes. This means that with these parameters the insert edge will have to be changed after 15 minutes of contact with the workpiece. E.g., if the contact time is 3 minutes in rough turning, you will have to change the rough turning edge every 5 parts. If you want a different tool life, multiply the cutting speed by the appropriate factor in this table:
Example:
If the cutting speed recommended in the catalog is 200 m/min and you want a tool life of 45 minutes, the multiplication factor is 0.75. You must therefore use a cutting speed of 150 m/min. For a life of 1 hour use a cutting speed of 140 m/min.
This you would do after selecting the insert grade, chip breaker geometry and cutting parameters as explained in this document and this earlier post in CNCetc.
This table is from a Sandvik turning tools catalog of 1995. I haven’t seen any such factors anywhere else. I’m assuming that these factors are still valid, and I’m assuming that they apply to all operations. Also, somehow no cutting tool catalog mentions the tool life that the recommended parameters are for. I’m assuming that they are for a life of 15 minutes.
Text course: CADEM NCyclopedia multimedia CNC training software.
