FR2525943A1 - Electrode for electroerosion tool - has fluid distributors fitting into holes to supply dielectric cleaning fluid - Google Patents

Abstract

The electrode has holes for supplying the dielectric cleaning fluid and/or for de-gasing. A fluid distributor is pressed into each hole and consists of a cylinder (1) of the same size as the hole. Each cylinder has an axial hole that becomes crossed slots at its outlet end. The axial hole's diameter reduces where it joins the crossed slots. The relative dimensions of the slots and of the axial hole are specified. The inner ends of the cylinders are bevelled to facilitate their insertion into the holes in the electrode. Alternatively, the distributors are solid blocks with square cross-sections and the fluid may flow between the outside of each block and the inside of its hole.

Description

 The present invention relates to a dielectric liquid distributor intended to be placed in the electrical and / or degassing watering holes drilled in some electro-erosion machining electrodes.

 It is known that in the electro-erosion machining technique, the dielectric spraying in the working zone can be done by holes drilled in the electrodes which, moreover, can also be pierced with degassing holes.

 These watering holes and degassing holes have the disadvantage of leaving on the machined parts "carrots" or "needles" which, during their formation, lead to instability of operation to the detriment of efficiency and which must then be eliminated by additional machining.

 It is known that some electrodes used for drilling small holes use channels of very small or spiral sections that prevent the formation of cores.

 These solutions have drawbacks - in the case of channels of very small sections, if we avoid the formation of cores, we have significant dielectric losses that require a particular dosage of the dielectric. In addition, it is limited to metal electrodes, - in the case of spiral channels, it avoids the formation of cores but there remains on the machined parts a kind of dome that must then be removed by additional machining.

 The main object of the invention is to avoid the formation of cores or needles on the machined parts with electrodes pierced with dielectric and / or degassing holes and, with the majority of these electrodes, whatever their size, their geometry and the nature of the material constituting them, without modifying the usual conditions of operation of these electrodes, by resorting to simple techniques.

 This object is achieved according to the invention by means of a dielectric liquid distributor intended to be placed in the dielectric and / or degassing watering holes drilled in the electro-erosion machining electrodes, a distributor characterized by the fact that it is constituted by a body of section close to that of the hole for which it is intended to be inserted by force and comprising a di electric distribution system comprising - a small diameter central channel d on a portion 12 of its length L and opening at one of its ends, - one or more notches passing through the axis of the body, from its other end and opening on its sides, the width of these notches being less than d and their length 11 greater than L minus 12, the distributor being placed in the tapping hole that the end with useful or several notches is in. the working area of the electrode.

 The length L of the splitter is equal to or less than that of the hole to which it is destined.

 The width has notches, is chosen the smallest possible and close to twice the work gap.

 The number of notches is determined according to the volume of dielectric to be distributed: the total section they offer must be compatible with this volume. there may be only one.

 Figures 1 and 2 illustrate by way of indication and not limitation the invention.

 Figure I shows an axial section of the splitter.

 Figure 2 shows a view from above. The splitter consists of a body I of length L and diantre, 6 being substantially the diameter of the hole to which the splitter is intended.

 The body 1 is pierced with a channel 2, of diameter d on a length 12, and opening on its end 3.

 Two notches 4a and 4b in the shape of a cross leave the other end 5 on a length 11. Their width is a.

 The body 1 is shown here with a chamfer (angle 300, diameter D).

This is intended to facilitate the establishment of the distributor in the hole.

 It is understood that in the context of the invention, it may not include.

 The splitter can be simply inserted into the hole. It can also be fixed to the electrode by any suitable means such as gluing, screwing, etc.

 Figures 3, 4 and 5 show, by way of example, some forms of electrodes to which one or more distributors according to the invention can be adapted.

 FIG. 3 shows in perspective, an electrode 6 for a rib of a die casting mold, provided with a distributor? single notch 4.

 Figure 4 mc.ltre in perspective, another electrode 8 for stamping die clevis, provided with several splitters 7a, 7b, 7e with two notches 4a and 4b. The splitter boxes, b and 7c are respectively inserted into bosses 9 and 10 of the electrode.

 Figure 5 shows in perspective. an electrode portion 11 for plastic mold, provided with several distributors 7, each provided with two cross notches 4a and 4b. One of the splitters being shown in position in the section made in the figure.

 It is clear that the invention can be applied to electrodes of large di mensicns exceeding the m2 for example. These generally include many watering or degassing holes in each of which we can place the appropriate distributor.

 In addition to its technical interest, the dielectric distributor has the advantage of being implemented by any user.

 It may happen that some electrodes have holes for watering or degassing relatively small diameter, between I and 3 mm, for example, to facilitate the removal of the core left on the workpiece.

The invention also applies to this type of electrode: it is sufficient for the user to enlarge the diameter of the holes over all or part of their length to be able to place distributors. The user will no longer have to eliminate the carrots.

The following table gives by way of example the dimensions in mm of some distributors according to the invention.

<Tb>

<SEP> N01 <SEP> N02 <SEP> N03
<tb><SEP> 3 <SEP> 3 <SEP><SEP> 6 <SEP> 10
<tb> n <SEP> 2 <SEP> 5 <SEP> 9
<tb> d <SEP> 1,1 <SEP> 2 <SEP> 4
<tb> L <SEP> 12 <SEP> 15 <SEP> 20
<tb> 11 <SEP> 5 <SEP> 6 <SEP> 8
<tb> 12 <SEP> 9 <SEP> 11 <SEP>. <SEP><SEP> 14
<Tb>
The width has notches being of the order of 0.2 millimeters.

 Another advantage of the invention is that the splitter can adapt whatever the material constituting the electrode, graphite, copper, cuprotungsten, etc. it suffices that it is made of a material of the same nature to have the manic behavior that the electrode material is in wear than in flow.

Claims (6)

R E V E N D I C A T IO N S  1. Dielectric liquid distributor intended to be placed in the dielectric and / or degassing watering holes drilled in the EDM electrodes, characterized in that it consists of a body of adjacent section that of the hole for which it is intended to be inserted by force and comprising a dielectric distribution system comprising - a central channel of small diameter d on a portion 12 of its length L and opening at one of its ends, one or more notches passing through the axis of the body, starting from its other end and opening on its sides, the width a of these notches being less than d and their length l1 greater than L minus 12, the distributor being placed in the map hole that the end with one or more notches is in the working area of the electrode.  2. Distributor according to claim 1 characterized in that the end opposite the notches is chamfered.  3. Dispatcher according to claim 1 or claim 2 characterized in that it is fixed to the electrode by any suitable means such as gluing or screwing.  4. Dispatcher according to any one of the preceding claims, characterized in that it consists of a material of the same nature as that of the electrode.  Electrode erosion machining electrode comprising one or more holes for spraying dielectric liquid and / or degassing, characterized in that the said hole or holes are provided with a distributor according to any one of the preceding claims. .  6. Electrode according to claim 5 characterized in that it consists of a material selected from graphite, copper, cupro-tungsten.