Product category:
EDM wire cutting
News Release from: Charmilles Technologies Corporation | Subject: CleanCut generator and Robofil 240/440 machines
Edited by the Manufacturingtalk Editorial
Team on 19 November 2002
EDM generator achieves cutting speed of
400mm2/m
Achieving a cutting speed of 400mm2/min, believed to be for the first time in the world, the generators fitted to the latest wire EDMs use a new current pulse shape.
The brand new CleanCut generator, fitted to Robofil 240/440 machines achieves a cutting speed of 400mm2/min for the first time in the world Breaking such a barrier was long considered virtually impossible by leading EDM OEMs EDM wire cutting has been characterized by extraordinary technical and economic development since its industrial beginnings during the 'seventies
This article was originally published on Manufacturingtalk on 13 Apr 2004 at 8.00am (UK)
Related stories
EDM generator achieves cutting speed of 400mm2/m
Achieving a cutting speed of 400mm2/min, believed to be for the first time in the world, the generators fitted to the latest wire EDMs use a new current pulse shape.
Charmilles EDM cell offers continuing expansion
Glasgow Precision is finding increasing benefits from the introduction of Wire Electro Discharge Machining (WEDM) into their production routines.
From the technical point of view, its progress has not been steady but rather in the form of technological leaps forward interspersed with periods of calm.
In less than 30 years, machining speed has been multiplied by a factor of 15.
The increase in cutting speed has been marked by the following main stages: * 1973: 30 mm2/min.
Further reading
Two-wire EDM improves productivity
In launching its revolutionary 'twin wire' Robofil 2030SI-TW, Charmilles has designed a system that allows machining with two different wires in automatic mode and cuts production times by 30%.
Award for toolmaker thanks to CNC investment
Toolmaker Avenue Mould now has two Charmilles Roboform 20 CNC spark eroders, fitted with Erowa tooling, and an automated Roboform 35 fitted with Erowa's PX robot
Subcontract engineer expands wire erosion facility
Subcontract engineering company Bedestone is continually expanding its operations and has increased its wire erosion capacity, investing in the latest technology from Charmilles Technologies
* 1990: 200 mm2/min.
* 2002: over 400 mm2/min.
This cutting speed is obtained thanks to the new shape of current pulses discovered and optimized by Charmilles engineers.
The CleanCut generator machines the part by using as its tool discharges of extremely high intensity at a rate of several million per second.
Such strong pulses have never previously been produced and mastered.
It has been accepted to date that the more energetic the discharges, the bigger the craters resulting from each discharge, with the result that the surfaces of the faces machined would be rough and the layer recast by the spark erosion would be thick.
But in fact in our case we get quite the opposite effect! CleanCut perfectly respects the integrity of the surfaces machined while at the same time cutting extremely rapidly.
Another important feature of this generator is its universality.
The programmable sparks can adapt to a wide range of materials such as: steel, tungsten carbide, boron carbide, titanium, aluminium, PCD, composite materials, exotic materials used in aeronautics, etc.
Although the sparks or discharges are perfectly programmable, nature has it that not all discharges are equivalent.
If it did not have the facility of processing and acting in real time on each discharge through specific software or hardware actions, CleanCut would never have been able to attain its present performances.
Charmilles PILOT-EXPERT system controls and acts on the discharges.
PILOT_EXPERT is an ultra-fast data acquisition system that analyzes each discharge individually, processes the data, and gives the order to the generator or other units of the machine to perform the appropriate actions.
To be more concrete, we can say that it is the brain of the process.
It makes it possible to cut at high speeds without wire breakage and with the guarantee of preserving the integrity of the surfaces machined.
XCC wire - not content with the fact that the CleanCut generator delivers very powerful and perfectly controlled discharges, Charmilles has developed a wire to make full use of the potential efficiency of the generator, the XCC wire.
This is a copper wire coated with a diffuse layer of zinc.
It is essentially in the zinc layer that the craters caused by the discharges will develop.
Because zinc is a metal with a low point of fusion and has a high latent heat of fusion and a high evaporation heat, the formation of craters absorbs a lot of energy.
Therefore only the remainder of the energy transmitted becomes diffused in the core of the wire.
As a result the core only heats up to a small extent, and it becomes possible to work with much higher discharge frequencies than with a wire without a zinc layer and hence to machine more rapidly.
This zinc layer forms what might be called a thermal shield.
The zinc layer has virtually disappeared in the direction of the wire feed: the thermal shield has successfully played its protective role in the core of the wire, which has remained practically intact.
High cutting speeds - it is by using the CleanCut generator assisted by PILOT-EXPERT and XCC wire that the cutting speed of 400mm2/min is attained under the real industrial conditions of a wire machine.
In these specific conditions, and for parts of simple shape, this speed can even be exceeded.
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