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General Mach Discussion / Re: Newbie (not so dopey a question) Help with Feed Rates and Spindle Speeds.
« on: June 18, 2014, 02:56:18 PM »
SFM is not feed per minute in case that was what you were thinking.
If you think of a lathe then 200m/min surface speed will let you know the rpm for a given diameter of material, as the diameter increases the rpm will decrease and vice versa. It is similar with a milling cutter except it is the dia of the cutter that affects things.
So for example on a lathe if the SFM required is 200 then at a dia of 100mm the RPM would be 637, if the dia was 200 then the RPM would be 318, if it was 25mm dia then the rpm would be 2547.
I tend to look up the manufacturers data to get Vc (surface units per min) and Fz (Feed per tooth) for a given tool I can then work out whatever I want from that
Attached is a xls spreadsheet that helps with that as it does the calcs for you.
Hood
If you think of a lathe then 200m/min surface speed will let you know the rpm for a given diameter of material, as the diameter increases the rpm will decrease and vice versa. It is similar with a milling cutter except it is the dia of the cutter that affects things.
So for example on a lathe if the SFM required is 200 then at a dia of 100mm the RPM would be 637, if the dia was 200 then the RPM would be 318, if it was 25mm dia then the rpm would be 2547.
I tend to look up the manufacturers data to get Vc (surface units per min) and Fz (Feed per tooth) for a given tool I can then work out whatever I want from that
Attached is a xls spreadsheet that helps with that as it does the calcs for you.
Hood