Общий каталог Palbit - страница 392

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threadingThread milling - InsertsThread milling - ToolholdersThread turning - OverviewThread turning - InsertsThread turning - ToolholdersThread turning - Spare PartsTechnical Data threadingThread milling - InsertsThread milling - ToolholdersThread turning - OverviewThread turning - InsertsThread turning - ToolholdersThread turning - Spare PartsTechnical Data Threading technical data Dados técnicos de roscagem | Datos técnicos de roscado E THREAD work methods | Métodos de trabalho de roscagem | Métodos de trabajo de roscado CALCULATe THE HELIX ANGLE AND CHOOSe THE RIGHT ANVIL E Calcular o ângulo de hélice e escolher o colchão adequado | Calcular el ángulo de hélice y elegir el colchón adecuado FLANK CLEARANCE ANGLE (a) Palbit toolholders are designed to tilt the insert when seated in the toolholder (10º for external,15º for internal tooling). This results in the differing flank clearance angles, based on the geometrya = arctan (tanØ/ 2 x tand) of insert. To ensure that the side of the insert cutting edge will not rub on the workpiece, it is mostimportant that the insert helix angle be correct - especiallyin profiles with small enclosed flankangles. This correction is provided by Palbit anvils.Where:a - flank clearance angled - Tilt angleØ - Enclosed flank angle CALCULATING THE HELIX ANGLE (b) Thread Inserts & Toolholders Rotation Feed Direction Helix Method Method FORMULA EX RH Anticlockwise Towards chuck Regular A Right Hand external EX LH Clockwise From chuck Reversed B IN RH Anticlockwise Towards chuck Regular a The helix angle is calculated by the following formula: Right Hand Internal IN LH Clockwise From chuck Reversed b b - Helix angle (º) EX LH Clockwise Towards chuck Regular D P - Pitch (1/TPI) Left Hand External EX RH Anticlockwise From chuck Reversed C N - No. of startsD - Pitch diameter (mm) IN LH Clockwise Towards chuck Regular dLeft Hand InternalIN RHAnticlockwiseFrom chuckReversedc Lead = P x NTPI = Threads per inches The helix angle can also be found using the diagram below THREAD INFEED METHODS | Métodos de roscagem infeed | Métodos de roscado infeed HELIX ANGLE DIAGRAM 5º 4º 3º b=2º b=1º RADIAL INFEED FLANK INFEED (modified) ALTERNATE FLANK INFEED 1.5º 1-3º b=0º Radial infeed is the simplest and quickest Flank infeed is recommended in the Use of the alternate flank method is method. following cases: recommended especially in large pitches The feed is perpendicular to the turning • when the thread pitch is greater than 16 and for materials with long cihps. axis, and both flanks of the insert perform tpi., using the radial method, the effective This method divides the load equally on the cutting operation. cutting edge length is too large, resulting both flanks, resulting in equal wear along Radial infeed is recommended in 3 cases: in chatter. the cutting edges. Alternate flank infeed • when the pitch is smaller than 16 tpi • for TRAPEZ and ACME. The radial method requires more complicated programming, • for material with short chips result in three cutting edges, making chip and is not available on all lathes. • for work with hardened material flow very difficult. 1.5º b=-2º b=-1º *For Multi-start threads, use the lead value instead of the pitch E - 780 E - 781