Основной каталог Kyocera 2016-2017 - страница 541

■ Infeed Methods Infeed Methods Features • The most common threading method. The cutting edge moves toward the center of the workpiece every pass. • Suitable for relatively small pitch size threading. • V-shape chips are generated and chip control may be difficult depending on workpiece material. Radial Infeed • Suitable for large pitch size threading. • The wear on the right side edge of the figure (no ap) tends to become greater. • Chips flow to one side. Flank Infeed • Revised compound methods of the above flank infeed method. • No “No ap.” condition. • Chips flow to one side. J 3゜〜5゜ Flank Compound Infeed ■ Lead Angle of Thread Threading Thread's Lead Angle β as shown in Fig. 1 decides from the Workpiece Diameter (Pitch Dia.). “D” and Lead “L” (in case of Single-start Thread, it is the same as Pitch “P”). By rolling a right-angled Triangle around a Cylinder and the Angle ACB in Fig. 2 becomes the Lead Angle β. The calculation formula is shown as follows. tan E = L = nP E : Lead Angle D: Pitch Dia. n: Number of Thread P: Pitch SD SD L : Lead (In case of single-start thread, it is equal to P, In case of n-start thread, it is equal to n×P.) Lead Angle E L A J E L C B SD (Fig.1) (Fig.2) (Fig.3) ■ Relief Angle of Thread Against this lead angle, the threading insert requires side relief angle α. TNN type threading insert is a negative insert and there is no relief angle. When installing the insert in the toolholder, the edge inclination angle γ (Fig. 3) is set, and at the same time front relief angle as well as side relief angle are generated to the insert. Side relief angle is described by the following formula. (Fig.4) tan D = tan J × tan ( T ) 2 (Table 1) A Symbol e.g.) Side Relief Angle D X D : Side Relief Angle D T J : Inclination Angle External Insert:10° Inserts t after Installing Insert Internal Insert :15° External Internal Y A-A Section A T: Insert's Thread Metric:60° Angle Tapered Pipe:55° 60° Thread (M, UN, NPT) 5° 49' 8° 47' 30° Trapezoidal:30° t T: Insert Thickness 55° Thread (W, G, PT) 5° 14' 7° 56' T J J X=T.sin J X Y=X.tan(T/2)=t.tan D 30° Trapezoidal (Tr) 2° 43' 5° 7' (Fig.4) t =T.cos J Ref. to Table 1 for the Side Relief Angle depending on the insert type. However, the side relief angle is set for 1° in the traveling direction by the toolholder itself, so that the actual side relief angle becomes α+1°. J47