Общий каталог Tungaloy 2020 - 2021 - страница 1631

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β Iβ3 90°-β1P I GradeInsertExt. ToolholderInt. ToolholderThreadingGroovingMiniature toolMilling cutterEndmillDrilling toolTooling SystemUser's GuideIndex User’s Guide - Technical Reference A Shim replacement method of S T- t y p e tools Compensation for the lead angle and tool relief angle B When the pitch is large or the screw diameter is small, the Thread angle Pitch P (large) lead angle becomes large and the effective relief angle on theadvance flank side β2 becomes small. In particular, this will Thread height Pitch P (small) = leadcause shorter life of the insert in the case of trapezoidal screwwith small flank angle. It is ideal without any interference for theC thread cutting insert to have an equal relief angle on both right and left. Replace the shim so that the rake face of insert faces Lead angle the thread groove direction (that is, β = β3).Calculating the lead angle Flank (large)Lead angle (small)α D The lead angle is calculated as follows: β = tan-1(R/πd) = tan-1(nP/πd) β:R: Lead angleLeadn : No. of threads Shim Insert θ E P : Pitch Toolholder d : Pitch diameter Calculating the relief angle P Threadgroove The relief angle β1 is calculated as follows:β1 = tan-1(tanθ •tanα) Pitchdiameter dSmall clearance(Possibility ofinterference)Lead anglecompensation Insert Fβ2Shim The α of a standard toolholder is 10˚ for external threadingand 15˚ for internal threading.Included angle2θθβ1External threading toolInternal threading toolβød(Pitchdiameter) β I–I cross section G 60° 30° 5.8° 8.8° 55° 27.5° 5.2° 7.9° 30° 15° 2.7° 4.1°29°14.5°2.6°4° πd H Accordingly, the effective relief angle is calculated as follows: β : Lead angle β2 = β1 + β3 - β β : Effective relief angle2β:Lead angle3compensation value I In other words, β1 = β2 when the thread lead angle is equal to the compensation value. Namely, the relief angle of the tool itself is equal to the effective relief angle. If the wrong compensation value is used, β1 > β2. The effective relief anglebecomes smaller and cause the interference between thefrank side of insert and the thread groove. Therefore, carry1°3°1° 2° J out com-pensation of the lead angle so that the following range is obtained: ±1˚ when the thread angle is 60˚ and 55˚ SSttaannddaarrdd CCoommppeennsated SSttaannddaarrdd CCoommppeennssaatteedd ±30˚ when the thread angle is 30˚ and 29˚Compensation of lead angle for shim less internal toolholders K When using internal threading toolholders without shim, the above- shown below. The final figure of the designation (-2 or -3) indicates 2° mentioned method can not be applied for lead angle compensation. or 3° lead angle to be used respectively. The toolholders without Therefore, special toolholders for large lead angles are available as these figures are for 1° lead angle. L M 1° 2° 3° SNR0016M16 SNR0016M16-2 SNR0016M16-3 Tungaloy L043