LMT Launches Shrink Toolholder System

LMT has developed a ready-to-run shrink-fit assembly toolholder system for CNC milling and turn milling. Suitable for the tool spindles of machining centres and driven tool units on turn-mill centres, the ISG 1000 bench-top unit allows users to overcome problems associated with the more traditional collets and hydraulic chucks. The portable unit measures 390 x 310 x 640mm, is powered from a three-phase plug-in source and will accommodate straight shank tool sizes between 3mm and 16mm diameter by up to 290mm in length.

Shrink-fit technology is said to provide a simple way of mounting milling cutters, drills and taps into a toolholder/backend and also provides advantages in the machining process. For instance, it creates a higher rigidity set-up between the machine spindle bearings and the tip of the cutting tool. Run-out at the tool tip should be less than 0.003mm total indicated run-out (TIR), which ensures a more effective rate of feed per tooth can be applied due to the more even loading.

This is especially important on small-diameter or long-series tools. Longer cutting life also results with improved levels of accuracy and surface finish being achieved. In addition, shrink-fit tool assemblies are better able to cope with acceleration of modern spindles and influence of centrifugal force that can allow a normal toolholding arrangement to suffer from slippage in the collet and even tool drop-out. The ISG 1000 unit takes less than 20seconds to heat the nose area of the toolholder through its 6.5kW induction heating coil.

The cutting tool shank is positioned in the holder and is retained as a single unit in the holder as it contracts under cooling. The speed the cooling process, included in the ISG 1000 package is a cooling adapter that enables the heat generated to rapidly dissipate via a series of strategically positioned heat-sink fins. Also included in the LMT UK package is an interchangeable disc, clamping ring and protective gloves.

LMT Installs Turn-Mill Centre In German Factory

LMT has installed five-axis simultaneous-machining centres and a turn-mill centre worth over GBP3.5m at LMT Fette's Schwarzebek manufacturing facility in Germany. LMT's Nanosphere coating acts as a heat shield but reacts elastically to protect the cutting tool from high thermal and mechanical stress. As a result, LMT Fette gear hobbing cutters can be run without coolant and should achieve a realistic increase in production life of at least a third over normal coated hobs.

The Twist-Free combination hobbing and deburring system enables the functions of a roughing hob, the in-cycle deburring of top and bottom flanks of each tooth and the finishing of the gear to be achieved in a single high-productivity cycle.

The single-arbour tool assembly can be applied to the hobbing of spur and helical gears and eliminates tooth-flank 'twisting' or convexity error that normally requires correction through separate finishing operations such as shaving, or grinding or honing in the hardened condition.