Pioneers in Machining Technology
A new range of slim profile hydraulic toolholders has been introduced by the Japanese manufacturer, BIG Daishowa, and is available in the UK through sales agent, NCMT. There is a choice of BBT 30, 40 or 50 BIG Plus face-and-taper-contact back ends (compatible with BT spindle machines), or the HSK-A63 taper.
Of slimline design, the toolholders are ideal for machining high precision features in restricted areas on components. Tool nose diameter ranges from 21 mm down to just 14 mm. The tools lend themselves particularly well to completing simultaneous 5-axis cycles without interference.
Runout accuracy is industry-leading, according to NCMT, at less than 3 microns when measured at 4D, ie a linear distance of four times shank diameter from the point of clamping. Each tool is pre-balanced, the quoted figure for BBT30 toolholders being under 3 g.mm, ensuring smooth, stable machining and good surface finish.
Infinitesimal levels of vibration extend cutter life and the chip load on each cutting flute is uniform. This is critical if the depth of cut is shallow, as is normally the case during finishing cycles for which these toolholders are normally used.
Across the range, cylindrical-shank cutters of 6 to 12 mm in diameter may be clamped and unclamped rapidly using a single screw and wrench, minimising production downtime. Repeatability of eccentricity is better than 1.5 microns.
Maximum rotational speed is 35,000 rpm, making BIG Daishowa's super-slim hydraulic toolholders especially suited to finish milling, grinding, precision drilling and reaming applications in the aerospace, medical and die/mould industries.
The Japanese manufacturer also produces standard hydraulic chucks with the same tapers plus additional HSK tapers up to A100 as well as C5 and C6 Capto shanks. They offer similarly precise toolholding for a range of tool sizes up to 32 mm diameter. Maximum spindle speed when using these tools is 20,000 rpm.
The toolholders are longer lasting than the traditional two-part construction sealed with O-rings and are maintenance free. Rigidity is improved by the short projection length and dual pressure points.