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Product category: Machinery and Production Equipment
News Release from: Walter GB | Subject: Helicheck NC 4 measuring centre
Edited by the Engineeringtalk Editorial Team on 29 June 2000

Cut those tool measurement cycle times

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Automatic measurement of cutting tools using CCD video cameras is provided by the Helicheck NC 4 four-axis measuring centre available from Walter GB of Redditch

The days are long gone when manual routines can be considered adequate for measuring cutting tools With drills, and milling cutters and reamers, for example, regularly being ground to geometry and concentricity tolerances of 10 microns - and some to within even five microns for high-speed machining tasks - the use of projectors or probes has proved inaccurate, slow and certainly unsuited to high-volume tool production and regrinding applications

Automatic measurement using CCD video cameras is one solution, as provided by the Helicheck NC 4 four-axis measuring centre.

Available from Walter GB of Redditch, Helicheck NC 4 accommodates tools in the diameter, length and weight bands of 200 mm, 300 mm and 40 Kgs.

Repeat accuracy on diameter measurements is + 0.002 mm and, on length is + 0.003 mm, and all inspection routines are in accordance with DIN ISO EN 9000.

Helicheck utilises a variety of tool inspection programs to minimise set-up and measuring times.

Software for cylindrical end mills and for tapered helical end mills are standard - those for drills and step drills, step tools, profile tools and knives, and grinding wheels, are optional.

The process is based on the use of two cameras.

One camera, which can be mounted horizontally in the Z axis, measures geometries (diameter, length, taper angle, corner and ball nose radii, for example) using the direct (diascopic) illumination method (silhouette).

The second camera, which moves horizontally in the X axis, measures internal contours such as spiral slots, chamfers, rake angles, chip gullet depth and front geometries using incident (episcopic) light (reflection).

In addition, tools are positioned by light beam in the vertical Y axis, for measuring their lengths, and with the machine's rotary (A) axis, are positioned with an angular accuracy of 0.0025 deg using an ISO 50 taper quick-clamp system.

This is used for the adjustment and measurement of tools with symmetrical geometry, such as diameters on three-flute milling cutters.

By rotating the tool, the machine recognises the three cutting edges through the periphery and precisely measures the diameter through the cutting edges.

Utilising similar HMC new generation control technology as applied to Walter's range of Helitronic tool and cutter grinders, Helicheck NC 4 operators can be quickly up to speed with tool inspection routines.

The Walter Window Mode (WWM) software is the key to this.

WWM eliminates the need for inspection expertise; if tool geometries are known, all that is required is input of measuring parameters in plain text, while a teach-in mode quickly and easily generates programs for special tools and components.

In automatic mode, the machine approaches the zero point and defined geometries, and the displayed and printed measuring record details the required sizes, admissible tolerances, actual sizes measured while showing a comparison between required and actual geometries.

An alternative programming method - recommended for free-form or complex geometries like tooth geometry on gear hobbing milling cutters - is based on scanning a known 'master'.

The operator defines only two limitation points for measuring, and Helicheck automatically searches for this contour within the limitation points.

Helicheck NC 4 is ideally suited to the workshop environment because, unlike traditional manual methods, it is unaffected by ambient temperature nor vibration due to its granite base that counters vibration and thermal expansion.

Operators can therefore check their own work, if required.

Users can, however, open up a new era of real-time post-process quality control savings by establishing an integrated communications link between Helicheck and the Walter Helitronic tool regrinding machine.

With a standard interface for both grinding and measuring routines (in the Walter WWM Windows mode), Helicheck NC 4 can automatically perform inspection routines independent of operator control while initiating immediate corrective feedback to minimise potential error.

The result is not only a consistent level of accuracy during tool grinding but also the availability of detailed quality reports to accompany every tool produced.

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