Two-in-one machine erodes PCD tools as well as grinds carbide and HSS tooling

Citation

(2002), "Two-in-one machine erodes PCD tools as well as grinds carbide and HSS tooling", Aircraft Engineering and Aerospace Technology, Vol. 74 No. 3. https://doi.org/10.1108/aeat.2002.12774cab.005

Two-in-one machine erodes PCD tools as well as grinds carbide and HSS tooling

Keywords: Machining, Grinding, Tools

Walter GB of Redditch, UK, claims that it has broken new ground in tool and cutter grinding with the launch of the two-in-one Helitronic Power + Diamond machine that combines CNC erosion with conventional CNC tool grinding for the fast, accurate and cost-efficient machining of both PCD and carbide and HSS tools (Plate 5).

Plate 5 CNC erosion combines with "conventional" tool grinding on the revolutionary Walter Helitronic Power + Diamond

Developed in response to customer demand, and to meet the increasing use of PCD tooling in industry sectors such as automotive and aerospace, the new machine utilises rotational erosion technology to machine PCD tools. It is reported to produce radii down to 0.1 mm and generate surface finishes that can eliminate the need for finish- grinding.

The five-axis Helitronic Power + Diamond is actually two machines in one: the machine can "revert" to being a Helitronic Power Production in only a few minutes – thanks to the use of the twin-head electrode/grinding wheel spindle unit and a dielectric that has been especially developed for this application. The dielectric is used as the machine's cutting fluid as well as the erosion dielectric, and can operate at up to 158°C

In Helitronic Power Production mode – with 24 kW spindle drive and digital drives that ensure rapid traverse rates of 15 m/min in all linear axes and 1200/sec on the rotational axes – the machine can accommodate tools 370 mm long (300 mm for face grinding) and 320 mm diameter. It can work on the basic body of a PCD tool – producing flutes and front geometries, for example – then quickly "switch" to erosion mode without operator intervention.

The range of PCD tools which can be machined includes circular milling cutters, milling tools, drills, core drills, combination tools as well as hogger saw blades. It is also possible to produce continuous peripheral clearance angles on tool profiles.

For erosion, a fully automatic measuring program determines all necessary parameters such as angle between axes, angular pitch and tool orthogonal rake, cutting edge position convex/concave and length of cutting edge.

The electrode dressing device allows users to create the appropriate contours on electrode diameters down to 6 mm. Also according to Walter, PCD tools with very narrow intervals between teeth can be accurately machined.

The machine uses walter's HMC 500 control technology – the CNC used across the complete Walter range – and the multi-tasking Windows NT operating system allows for parallel data entry during the erosion/grinding process.

An integrated editor allows the user to easily generate profiles and to transfer and change existing profile DXF data directly on the machine or via a PC workstation.

Walter also reports that cutting tool manufacturer Hydra Clarkson International, a Jasco International company, is using a Walter Helitronic Power Production CNC tool and cutter grinder to successfully manufacture aerospace fir tree root form cutters.

In one instance, the machine is being used to produce small batches (one- to 10-off) of 32 mm brazed and solid carbide fir tree root form cutters with a 15deg helix angle and radial relief style form grinding in a single setting.

Supplied by Walter GB of Redditch, the five-axis Helitronic was "the ideal choice,, for this application as well as for the production of other special forms at the Sheffield company. according to Hydra Clarkson's works manager Tony Egley.

Cutters of similar form and from 25 mm diameter up to 150 mm diameter are being manufactured by Hydra Tools on the Helitronic – and in all cases the WWM Walter Window Mode graphics-assisted Package 7 – Profile Tools' programming routine makes for user-friendly programming.

The Helitronic Power Production can handle tools 370 mm long (300 mm for face grinding) and 320 mm diameter.

Part of the Jasco family of companies and employing 200 people in the UK. Hydra Clarkson International produces thousands of HSS and carbide cutting tools (cutters, drills and taps as well as applicationspecific tools) each week for sale at home and abroad through a network of distributors and dealers as well direct to end users.

The company utilises state-of-the-art equipment at its Sheffield manufacturing plant as well as Jascols US operations and, says Tony Egley, the Walter machine has proved itself on fir tree root and other special forms.

Details available from: Walter GB Ltd. Tel: +44 (0) 1527 60281; Website: http://www.walter-ag.de