Общий каталог Mitsubishi 2020 - 2021 - страница 1747

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DRILL TERMINOLOGY

AND CUTTING CHARACTERISTICS

y CUTTING EDGE GEOMETRY AND ITS INFLUENCE

As shown in table below, it is possible to select the most suitable cutting edge geometry for different applications. If the most suitable cutting edge geometry is selected then higher machining efficiency and higher hole accuracy can be obtained. a Typical Cutting Edge Geometries

Grinding NameGeometryFeatures and EffectUse
Conical• The flank is conical and the clearance angle increases toward the center of the drill.• For general use.
Flat• The flank is flat and facilitates cutting.• Mainly for small diameter drills.
Three Rake Angles• As there is no chisel edge, the results are high centripetal force and small hole oversize. • Requires a special grinding machine. • Requires grinding of three sides.• For drilling operations that require high hole accuracy and positioning accuracy.
Spiral Point• To increase the clearance angle near the center of the drill, conical grinding combined with irregular helix. • S type chisel edge with high centripetal force and machining accuracy.• For drilling that requires high accuracy.
Radial Lip•The cutting edge is ground radial with the aim of dispersing load. •High machining accuracy and finished surface roughness. •For through holes, small burrs on the base. •Requires a special grinding machine.• For cast iron and light alloy. • For cast iron plates. • Steel
Center Point Drill• This geometry has two-stage point angle for better concentricity and a reduction in shock when exiting the work material.• For thin sheet drilling.

y WEB THINNING

The rake angle of the cutting edge of a drill reduces toward the center, and it changes into a negative angle at the chisel edge. During drilling, the center of a drill crushes the work, generating 50─70% of the cutting resistance. Web thinning is very effective for reduction in the cutting resistance of a drill, early removal of cut chips at the chisel edge, and better initial bite.

Geometry

P X type XR type S type N type

The thrust load substantiallyThe initial performance isPopular design, easy cuttingEffective when the web is
reduces, and the biteslightly inferior to that of the Xtype.comparatively thick.
Featuresperformance improves. Thistype, but the cutting edge is
is effective when the web istough and the applicable range
thick.of work materials is wide.
MajorGeneral drilling and deep holeGeneral drilling and stainlessGeneral drilling for steel, castDeep hole drilling.
Applicationsdrilling.steel drilling.iron, and non-ferrous metal.