Carbide end mill and cutting method using the end mill

A carbide end mill which includes a plurality of wavy peripheral cutting edges each having alternate crest portions and trough portions, or a plurality of peripheral cutting edges each having a plurality of nicks for breaking chips, wherein, when a certain peripheral cutting edge is considered a reference peripheral cutting edge having reference phases, wherein the distance of the reference phase is an amount corresponding to a value obtained by dividing the pitch of the nicks or waveform of the reference peripheral cutting edge by the number of the cutting edges;

• and the phase of at least one of the remaining peripheral cutting edges is deviated in the direction of a tool axis from the corresponding reference phase by an amount of 5% or less, excluding 0%, of the pitch,
• wherein, the carbide end mill includes the plurality of peripheral cutting edges, end cutting edges, and gashes each composed of a plurality of gash surfaces;
• the plurality of gash surfaces include a first gash surface serving as a cutting face of the corresponding end cutting edge, a second gash surface provided on the side toward the rotational center of the tool axis of the end mill, and a third gash surface provided on the peripheral side of the end mill;
• a first gash angle of 15° to 35° is formed between a crossing portion between the first gash surface and the second gash surface, and a plane perpendicularly intersecting the tool axis;
• a second gash angle of 40° to 60° is formed between a crossing portion between the first gash surface and the third gash surface, and the plane perpendicularly intersecting the tool axis;
• and the length of a connection portion between the second gash surface and the third gash surface is not less than 5% the tool diameter as measured from the tool rotation axis and less than 20% the tool diameter.