FR3050133A1 - METHOD FOR RIGIDIFYING A CUTTING GUIDE, CORRESPONDING DEVICE AND CUTTING GUIDE - Google Patents

Abstract

The present invention relates to a method for stiffening a guide (8) for cutting a workpiece in a block (1) made of metallic or composite material along a line (5) of section having a determined trajectory, the cut taking place by cutting means (7) comprising a support (9) flexible and / or articulated maintained by the guide (8) along said path. At least one hole (10; 11; 19; 20; 21; 22; 23; 24; 25; 72; 73) passing through the block (1) in a normal direction on or at a predetermined distance from the line ( 5), and is taken up with a stiffening rod (14; 15; 45; 46; 47; 60; 74; 75) introduced into said hole (10; 11; 19; 20; 21; 22; 23; 25; 72; 73) the forces exerted on the guide (8) by gravity and by said cutting.

Description

METHOD FOR RIGIDIFYING A CUTTING GUIDE, CORRESPONDING DEVICE AND CUTTING GUIDE

The present invention relates to a method of stiffening a cutting guide of a workpiece in a block made of metallic or composite material along a cutting line having a determined trajectory, the cutting taking place by cutting means comprising a flexible support and / or articulated held by the guide along said path.

It also relates to a device for cutting a part in a block made of metallic or composite material implementing such a method and a corresponding rigidified guide.

It finds a particularly important application although not exclusive in the field of the precision cutting of mechanical parts along a path having at least one point of inflection, for example at least partly sinuous, and in particular for the formation of blanks parts made of metal material (in particular aluminum, titanium, steels) or composite (in particular with thermosetting or thermoplastic matrices and carbon fibers), for example used in aeronautics.

More precisely, and in the case of manufacturing a metal mechanical part, it is known to start from a block of raw material, for example a foundry material, and then to machine it so as to obtain a blank (semi-finished product) of the part sought. This blank is then refined for the formation of the finished product.

The more the resulting blank is close to the desired final shape, the less it is necessary to rework the workpiece and the smaller the material falls.

There is therefore a need for a device and a method for accurately producing complex shapes in a blank, and this as close as possible to the shape of the part, which allows to limit the number of steps and the loss of material.

Already known (FR 8 007 311) cutting devices of parts in a block following a determined path formed by a guide of the cutting member.

Although efficient, these nevertheless have disadvantages.

Indeed, particularly in the case of large parts, especially in width (that is to say in the size of the block corresponding to the length of the guide), the mechanical deformation of the guide due to gravity and efforts on that during cutting, it is not possible to guarantee a geometrical conformity of very high precision, for example between the median cutting line of the desired theoretical trajectory and that actually achieved (maximum distance between the two curves of less than 3 mm).

There is also a risk of not having enough material on one of the two cut parts to achieve the finished part provided in the latter.

The lack of precision of the cutting may furthermore require an intermediate re-machining, between the state of roughing and that of final part, always more complex and expensive, knowing that the geometrical non-conformities appear precisely preferentially in places of inflection of the guide's trajectory, which is difficult to re-read later.

To avoid the deformation of the guide a solution may consist in increasing its thickness. But this is to the detriment of the consumption of material, the cutting line being wider and thus causing more loss of material.

The present invention aims to provide a device and a cutting method better than those previously known to the requirements of practice, especially in that it allows to reduce the thickness of the cutting guide to the minimum by taking the main efforts at the places where there is material not used in final, in that it allows to cut large widths, while allowing the trajectories with changes of direction many and close together, and it for parts of important dimensions, with a large precision.

Important dimensions are understood to mean dimensions of parts to be cut, in particular of width greater than 600 mm, for example greater than 1 m, 1 m 50, 2 m or 4 m or more and / or length greater than 600 mm, 1 m or 5 m or even of the order of a few tens of meters for example 30 m or more. The thickness of the block in which the parts are cut can however be less than 350 mm (often the case in aeronautics) or greater than 600 mm, and this without limitation. It may for example be less than 200 mm, for example of the order of 100 mm, the limit being that of the thickness of the parts obtained and the transverse size of the cutting slot.

The present invention allows the nesting of several complex blanks and / or part of the idea of progressively penetrating the cutting system inside the block, not only the cutting part, namely the cutting inserts or the cutting blade. saw, but also its guiding part namely its guide and the stiffening means of said guide.

To do this, the invention proposes in particular a method for stiffening a cutting guide of a workpiece in a block made of metallic or composite material along a cutting line having a determined trajectory, the cutting taking place by means of section comprising a flexible and / or articulated support held by the guide along said path, characterized in that at least one through hole in the block is pierced in a normal direction on or at a determined distance from the section line, and taking up with a stiffening bar introduced into said hole the forces exerted on the guide by the gravity and by said cut.

Such a stiffening process can be used as and when cut in the thickness and the entire length of the block, the introduction of links and / or cutting inserts, and / or the saw blade and guide are then progressively in the block of material without risk of deformation.

In advantageous embodiments, it is also and / or more recourse to one and / or the other of the following provisions: the hole is drilled prior to cutting; the bar being fixed on the guide and extending at least partly projecting in front of the guide relative to the direction of advance of the cut, the bar is inserted into the orifice beforehand and as the cut ; the bar is fully inserted into the orifice before cutting; - The bar being fixed on the guide and extending projecting behind the guide relative to the direction of advancement of the cut, the bar is inserted into the hole later and as and when cutting; the steps of drilling the orifice and cutting the workpiece simultaneously are carried out; - We take the forces exerted on the guide during cutting by mechanical contact between the guide and the bar; the determined distance between the guide and the bar is calculated so that the cross section of the guide and the cross section of the bar are at least partially intersecting; - The hole is drilled centrally on the cutting line; the method comprises the use of at least two guide holes and at least two corresponding stiffening bars, for example at least three or at least five corresponding holes and bars; - The orifices and bars are at least partly arranged to be located on either side of the section line for example alternately on both sides; the bar comprises at least one cylindrical portion, advantageously arranged to cooperate slidingly with the orifice; - The cutting path changing at least once direction, the change taking place on a given area, it stiffens the guide near and / or in contact with said determined area; - The bar is greater than or equal to the length of the cut in the direction normal to the cutting line (determined path); the guide is stiffened by contact with the bar via at least one sliding pad; - The cutting means comprise at least one cutting plate mounted projecting from a side face of the support. The invention also proposes a cutting device implementing the stiffening method as described above.

It also proposes a device for cutting a part in a block made of metallic or composite material along a section line having a determined trajectory, comprising cutting means comprising a flexible and / or articulated support extending along said trajectory and a guide of said support having said determined trajectory, characterized in that it further comprises means for drilling at least one through orifice in the block in a direction normal to the determined trajectory on or at a determined distance from the line cutting and at least one stiffening bar arranged to cooperate with said orifice, and resume the forces exerted on the guide by the gravity and by said cut when the bar is inserted into the orifice.

It also proposes a stiffened guide for cutting a workpiece in a block made of metallic or composite material along a cutting line having a determined trajectory, arranged to collaborate with cutting means comprising a flexible and / or articulated support extending along said path, characterized in that it comprises at least one stiffening bar adapted to be introduced into an orifice previously drilled in the block, of recovery of the forces exerted on the guide by gravity and by said cut.

Advantageously, the stiffened guide comprises several bars, for example at least three bars, for example fixed rigidly or slidably (by pads for example) to the guide, for example on either side of the guide. The invention will be better understood on reading the following description of embodiments given below by way of non-limiting examples.

The description refers to the accompanying drawings in which:

Figure 1 is a perspective view schematically showing a stiffening device of a cutting guide of a workpiece in a block illustrating a first embodiment of the method according to the invention.

Figure 2 is a front view in a block showing another embodiment of a device implementing the method according to the invention.

Figs. 2A-2C are perspective views of guide portions with stiffening bars arranged according to various embodiments of the invention.

Figure 3 is a front view schematically showing a device according to one embodiment of the invention.

Fig. 3A is a schematic side view of a drilling, cutting and support device of the guide according to an embodiment of the invention.

FIG. 4 is a diagrammatic representation in perspective of a numerical simulation of the forces undergone by a sinusoidal shape guide during cutting.

Figure 5A is a rear perspective view of a sheet metal plate and (partial) cutting and stiffening means for guiding it according to another embodiment of the invention.

Figure 5B is a perspective view in front of and near the other side of Figure 5A.

Figure 6 shows the connection detail of the bar to the guide of Figure 5B.

FIG. 1 shows a block 1 of substantially parallelepipedic material of length L, of width 1 and of thickness E, for example made of metallic or composite material (for example thermosetting resin and carbon fibers) of composition conventionally adopted in the context of the manufacture of airplane or aerospace or automobile parts, extending around a longitudinal plane.

The length L and / or the width 1 of the block 1 is greater than 600 mm and / or the thickness E is greater than 600 mm (although this thickness can be much smaller, as is the case in aeronautics where the thickness is often less than 350 mm).

The block 1 is cut longitudinally in its thickness and makes it possible to obtain two blanks, an upper 2 and a lower 3, for forming at least one final piece (not shown).

The cut 4 has been made along a section line 5 having a determined trajectory, the trajectory being for example a curve 6 as represented in FIG. 2.

It is produced by cutting means 7 mounted in a guide 8, which will be detailed below (with reference in particular to FIGS. 2A to 2C) and which comprise a flexible and / or articulated support 9 extending along said path .

The block 1 comprises two cylindrical orifices 10, 11, for example with a diameter of between 3 cm and 10 cm, which guide, passing through the end-to-end piece between the front lateral faces 12 and rear 13 of the block, opposite longitudinally.

The orifices 10, 11, for example made by drilling, are made in a direction normal to the section line 5.

Each orifice 10, 11 is provided with a cylindrical rod 14, stiffening, introduced and cooperating frictionally in the corresponding orifice.

The two bars 14, 15, namely the first bar 14 and the second bar 15 have a length greater than or equal to the length L of the block, and therefore of the cut in the normal direction, and are here projecting and protruding from the one and / or both front faces 12 and rear 13.

In this embodiment, the first bar 14 is located below the cutting means 7, for example substantially in a point of inflection zone of the curve 6, and the second bar 15 is located above, here and for example substantially in a zone of maximum change of direction of the curve 6, the two bars 14, 15 being each at a determined distance from the line of section (for example a few millimeters, for example typically 2 to 5 mm and in locations of the block that will not be needed in the composition of the piece or pieces obtained for cutting.

In this embodiment the two orifices 10, 11 and the two bars 14, 15 are arranged to be located on either side of the section line 5, which will ensure optimized guidance.

The bars 14, 15 thus resume the forces exerted on the guide 8 in particular by the gravity and by said cut.

In the remainder of the description, the same reference numbers will be used to designate similar and / or identical elements.

More precisely in FIG. 2, the curve 6 is formed by the location of the points M (x0, yo) where x0 and y0 are functions of a parameter t and such that:

This trajectory defines a line 16 of section of width 2e itself defined by the data of curves 17 and 18 spaced apart from each other by 2e. The line 16 of section is centered on the curve 6 which also forms the neutral fiber of the cut.

Curves 17 and 18 are then defined as follows:

The path to perform the cutting is in a curve 6 which has at least one change of direction.

For example, the path has at least one inflection point I, for example having a sinusoidal or substantially sinusoidal shape.

In this embodiment, the block 1 comprises seven orifices 19, 20, 21, 22, 23, 24, 25 of guides pierced prior to cutting.

The orifices, and therefore the corresponding bars, are distributed along the curve 6 and at a determined distance from the guide 8 and / or the line 16 and / or all of them in whole or in part. The orifice 22 is entirely at a distance from the guide, for example at 1 cm.

For the orifice 24, the distance is calculated so that the cross section of the guide 8 and the cross section of the corresponding bar are at least partially intersecting. In this way the bar exerts an increased pressure on the guide 8.

The orifices 19, 20, 21, 23, 25 are in turn drilled centrally on the line 5 of section, which allows to resume the efforts symmetrically.

The orifices 19, 20, 21, 22, 23, 24, 25 are cylindrical, i.e. of circular cross section, as are the corresponding bars and thus allow the isotropic recovery of the forces. They may be of any other shape, for example oval, allowing an optimization of the recovery of the forces in a particular direction, or of polygonal section, as long as the points or lines of contact between guide and bar are sufficient to resume efforts while by minimizing the forces of friction.

In general, the bars must be of section and rigidity suitable for the recovery of forces and for their easy insertion into the orifices, for example homothetic or corresponding thereto and advantageously comprise at least one cylindrical portion of distribution of said efforts.

For example they comprise a section having an angular range less than 150 °, for example less than 120 ° in which the section is circular.

The bars may be of any material but are advantageously made of steel and / or have a high intrinsic rigidity, for example a Young's modulus greater than 200 GPa, for example greater than 380 GPa, and have a high elastic limit (for example greater than at 800 MPa, for example greater than 900 MPa).

They are also adapted to slide in the orifice in a manner known per se to those skilled in the art, for example by having a good surface finish obtained by machining and / or polishing and / or by producing texture.

FIGS. 2A to 2C show a portion of the cutting means 7 according to the embodiments of the invention more particularly described here.

They comprise an endless chain 26 which is symmetrical around a longitudinal axial plane 27.

The chain is formed by an assembly of articulated links 29, 30 having on a lateral blank 31 platelets 32 (fixed on a seat or plate holder 41), each plate being provided with a cutting edge 33 projecting in a normal direction. (mixed line 34) with respect to the blank 35.

The cutting means 7 therefore comprise at least one cutting plate mounted to project from a lateral face of the support.

The guide 8 comprises a longitudinal chamber 36 for passage of the chain 26.

The guide is of determined width H, the plate 31 being arranged to perform the cutting on a 2nd width of cutting line greater than H. The enclosure 36 comprises a bottom 37 on one side and is provided on the other side with a perforated side wall 38 that defines a longitudinal slot 39.

The chain 26 comprises a number of lateral guide cheeks 40 distributed regularly along the chain 26. The lateral cheeks 40 comprise peripheral edges 41 arranged to cooperate by friction (or rolling) with the sides 42 of the slot 39. on the outer face of the perforated side wall 38.

More precisely each articulated link 28, 29 of the chain 26 is formed by two parallel axes interconnected by junction plates or pads, the lateral cheeks forming some of these junction pads between two adjacent axes.

To ensure the articulation of the chain 26, there is of course a common axis between two adjacent links, the connecting pad of a link being offset laterally with respect to that of the adjacent link, in a manner known per se.

The wafer 31 of cut is fixed on the wafer holder 32 itself opposed to a side cheek 35 or portion cooperating with friction with the enclosure

In the embodiments more particularly described here, the enclosure 36 comprises two longitudinal ribs 43, 44, namely a first internal central rib 43 arranged to cooperate in rolling or friction with the articulation axes between links and a second rib 44 with respect to the first rib, the orthogonal distance between the first and the second rib being equal to D (axis diameter) + d with d 0,5 0.5 mm, for example <0.1 mm.

The guide 8 comprises a bar 45, 46, 47 for stiffening, fixed or not on said guide.

In the embodiment of FIG. 2A, the bar 45 is fixed on the guide in the thickness of said guide 8.

For example, the curve formed by the generator axis of the bar and the neutral curve of the cut are intersecting.

More precisely, the bar 45 extends towards the rear of the guide with respect to the slot 39, for example from the bottom 37 of the enclosure 38 of the guide, and thus projects towards the rear of said guide 8 with respect to the direction of advanced cutting (longitudinal).

The bar 45 thus protrudes from the guide 8 on the opposite face of the guide 8 relative to the cutting plates 31.

The bar 45 being inserted into the corresponding orifice as and after measurement but after cutting, this arrangement allows the free passage of the chain 26 and the plates 31, the bar 45 then being present between the two cut blanks, after leaving the means 7 for cutting the block at the end of cutting, which keeps spaced the cut pieces vis-à-vis, after said cutting.

In other words, the stiffening bar 45 thus makes it possible to prevent the pinch / droop of the upper blank 2 on the lower blank 3.

In the embodiment shown in FIG. 2B, the bar 46 is fixed on one of the faces of the guide 8 and extends longitudinally at least partly projecting in front of said guide 8 with respect to the direction of advance of the cut ( on the side of the cutting plates 31).

In this embodiment, the bar 46 comprises a groove (not shown) or clearance on its circumference and on an end portion of said bar 46 to allow the passage of the cutting plates 31.

In this way, the bar 46 being inserted in the corresponding hole beforehand and as the cutting progresses, the guiding function is ensured from the beginning of the cutting operations and also limits the precise positioning constraints at the start of the cutting. cutting when the guide is out of the block.

The guide bar may also not protrude longitudinally from the guide.

The fixing of the bar 45, 46 on the guide is carried out irremovably or removably, for example by welding or screwing (which then allows disassembly) without exceeding the screw head of the space defined by the section of bar.

FIG. 2C shows the same guide arrangement as FIG. 2B, but this time with a bar 47 entirely at a distance from the guide, which allows a good escape of the cutting means, the distance existing between the guide and the bar being calculated to allow, by material interposed block, sufficient recovery of efforts to prevent deformation.

FIG. 3 shows a device D for cutting a workpiece from a block 1 (mixed line) made of metallic or composite material. The device D comprises the guide 8 along a determined trajectory, an endless chain 26 (see FIGS. 2A to 2C) which is in a manner known per se driven on one side by a rotary ring 4 8 driven in rotation by means of a geared motor 49 and 57 for example electric. The whole is carried by a carriage 50 of support (symbolized in phantom in the figure), and comprises a rolling element 51 to ensure the translation of the system parallel to a support table of the part (not shown), the element 51 being arranged to cooperate with the surface 52 of a guide plate 53. The return of the chain is provided by two pinions 54 crazy or not, spacing the chain.

The motor 49 is controlled in a manner known per se by an automaton (not shown), to perform the cutting according to the chosen modes (cutting speed, advance etc ...).

The device D also comprises a structure 55 for supporting the assembly and means 56 for measuring the tension of the chain, its speed and / or its degree of wear, etc., here again in a manner known in itself. -even, measures to which is enslaved the operation of the automaton.

The device D also comprises means 58 for drilling and / or drilling the orifices in the block symbolized by circles, known in themselves and slaved to the PLC in a programmed manner according to the specifications of the cut.

These are for example a drilling tool with removable plate of the type drill to a lip with a solid carbide head or steel with carbide inserts reported brazed to the body (for example drilling tool known under the reference ΤΥΡΟΙ of the company Botek ).

The orifices may be made prior to cutting by these drilling means. In this case the bars can be as we have seen, either fixed on the guide 8 or inserted independently of the guide 8.

In another embodiment, the holes are drilled and the part is cut simultaneously or substantially simultaneously, the drilling / drilling means then being controlled in combination with the cutting means.

In Figure 3A is shown an embodiment for such simultaneity. To do this there is provided a set 59 provided with a body 60 which will form the stiffening bar and which has at its end a drill head 61, for example of the drill type.

In recess with respect to the drilling head 61 and on the radial periphery of the rod body 60 is fixed the guide 8 of the cutting means 7, at the end of which is mounted the cutting chain 26, on the side of the drill 61.

The body 60 comprises on its radial periphery opposite the chain 26 a groove 62 for the passage of said chain 26.

In one embodiment, a single motor simultaneously drives the drill 61 and the chain 26.

The body 60 then comprises two bearings 63, 64 mounted radially on the body which transmit the movement from one to the other in a manner known per se.

In another embodiment, two separate motors respectively drive the drill and the chain.

The body 60 further comprises and for example two pads 63, 64 mounted radially on the body which allow the sliding of the assembly 59 in the block, the guide 8 being stiffened by contact with the bar or the body 60 via said sliding pads 63, 64.

The shape of the path and therefore of the guide plays an important role on the cutting forces and on the rigidity of the guide, efforts that are therefore taken into account for the optimized positioning of the stiffening bars.

FIG. 4 is for example a guide and its amplitudes of deformations obtained by numerical simulation during cutting.

It is found by calculation, according to the materials (block, guide, chain ...) and their dimensions (width of the cutting line, desired cutting speed etc) that in the example taken, the guide will have seven zones among which:

The zones with end portions referenced 65 and 71 which undergo in the example deformations (arrows) less than 0.085 mm;

The zones referenced 66 and 70, which are more spaced apart, undergo deformation, for example, of between 0.085 mm and 0.165 mm, the zones referenced 67 and 69 undergoing greater deformations (here between 0.165 mm and 0.190 mm being up to at 30% of the tolerance on cutting precision), the median zone referenced 68, being that which generates (without stiffening) the largest deformation (here between 0.190 mm and 0.3 mm).

Based on this analysis and these calculations, it will be possible to determine the location and composition of the stiffening system (holes / bars).

Thus the orifices will be made in the areas where the deformations of the guide 8 would be the most important, especially in the middle of the guide 8 mainly but also to changes in direction of the guide and / or near the areas where there is the least thickness of material between the cut line 6 made by the cutting means 7 and the theoretical geometry of the finished part from the blank.

Of course, these orifices must be made in portions of the block that are not part of a part whose geometry is integrated in the optimized locations calculation program.

FIGS. 5A and 5B show a block 1 before cutting comprising two guide orifices 72, 73, the cutting means 7 being in position to start cutting.

They therefore comprise a guide 8 with a length L and a width 1.

The width, for example, greater than 100 mm makes it possible to ensure part of the recovery of the forces by working with the bars but reduces the sliding of the guide 8 in the block 1.

The longer the length 1 / of the guide, corresponding to the unfolded guide, is important, the greater the efforts it endures are important.

5B show the bars 74, 75 inserted in the orifices 72, 73. They are for example formed by hollow tubes, which reduces their weight eg steel referenced XC38 in AFNOR standards.

Each tube (closed on its front side of the cutting tips side) can be perforated vis-à-vis the cutter and can be used as a lubrication channel.

FIG. 6 shows an embodiment of the stiffening bar 75 which consists of a first tube portion 76 fixed to the guide 8 and threaded at its end portion 77. This end portion 77 is connected to a second portion 78 of the same diameter as the first portion, radially threaded at its end 79 to attach to the end portion 77 so that there is no extra thickness.

The first tube portion 76 has a passage 80 through which the cutting means 7 and their guide 8 pass.

This is for example formed by combining two openings on two nested half-tubes, facing each other forming the tube portion 76.

The edge of this light directed towards the second tube portion 78 comprises at least one abutment shoulder 81 forming a locking system in translation of the bar 75 at the level of the guide 8.

This avoids the risk of sliding one relative to the other which would reduce this clearance zone.

We will now describe a cut made according to one embodiment of the invention using the device of FIG.

After choosing the block of metal or composite material corresponding to the parts that we want to manufacture, we program through the controller, the cut that we want to achieve.

This programming includes for example the steps of: - choosing a block reference in a database comprising, for example, numerical modeling of the geometry of said block, numerical modeling of the geometry of the blanks and / or the cutting line, determination geometry including the size, position and trajectory of the orifices. This determination is made so that the orifices are in an area where there is no interference and / or overlap with the finished part, and so that the recovery of gravity and cutting forces by form bars and constitution determined, is optimized to limit the deformations to tolerances allowed.

After placing the block on the machining frame, the holes are made, then the guide bars are introduced simultaneously with the cutting of the pieces and / or posteriorly.

The guide is thus stiffened near and / or in contact with the determined zones.

For example, for a path comprising two straight segments opening on two opposite faces of the block and forming an angle, for example 5 °, two corresponding holes are made on either side of the cutting line and inserted into the orifices. thus made, prior to cutting, two stiffening bars.

The guide is itself chosen according to the parameters necessary for the manufacture and may for example be removably and removably designed to allow thicknesses of 2nd cutting lines of different widths, for example between 1cm and 2cm.

If in one embodiment, the orifices are made prior to cutting, and the bars inserted fully before cutting or, the bars being fixed to the guide, simultaneously with cutting (by penetrating and advancing in the block bars as and when as the guide advances), in another embodiment, the drilling is concomitant with the cutting.

This is then carried out in a manner known per se, the lubrication of the chain being carried out continuously, for example by means of an injection of lubricating liquid at different injection points of the guide regularly distributed along the this and / or by supplying the liquid via the stiffening tubes.

Efforts are then passed on the bars that avoid deformation guide.

The block 1 can be moved to perform the cutting or a contrario, it is the device itself that comes to move on the block 1 which was then previously fixed on a support (not shown) also playing a role of stiffener.

The following is the case where the cutting tool is formed of a guide and cutting inserts fixed on a chain.

But it goes without saying that this is only a non-limiting embodiment.

Referring to Figure 3 and to achieve the cutting, guide and chain are gradually pushed against the block 1 separating gradually the upper and lower parts 2 and 3, the chain 26 is here pushed in the transverse direction of the block 1.

The stiffening bars then allow to maintain the guide in position within the required tolerances for the duration of the cutting.

As the chips cut the chips are easily evacuated, especially because of the existence of the chipbreaker.

The blanks are also progressively captured and maintained in a manner known per se, and then evacuated.

Thanks to the invention it is thus possible to obtain parts with exceptional accuracy the guide could be kept perfectly in place without deformation and with a very small loss of material and / or metal.

Parts that are very close to the final machined form can be finalized without much difficulty.

As goes without saying and as it follows from the foregoing, the present invention is not limited to the embodiments more particularly described. On the contrary, it embraces all the variants and especially those where the bars and orifices are of different shapes and geometry or those where the cutting tool is different (saw blade, cable, wire ...).

Claims (20)

1. A method of stiffening a guide (8) for cutting a workpiece in a block (1) of metal or composite material along a line (5) of cutting having a determined trajectory, the cutting being effected by means (7) cutting comprising a support (9) flexible and / or articulated maintained by the guide (8) along said path, characterized in that is pierced at least one orifice (10; 11; 19; 20; 21; 22; 23; 24; 25; 72; 73) passing through the block (1) in a normal direction on or at a predetermined distance from the cutting line (5), and resumed with a bar (14; 15; ; 46; 47; 60; 74; 75) of stiffening introduced into said orifice (10; 11; 19; 20; 21; 22; 23; 24; 25; 72; 73) the forces exerted on the guide (8) by gravity and by said cutting. 2. Method according to claim 1, characterized in that pierces the orifice (10; 11; 19; 20; 21; 22; 23; 24; 25; 72; 73) prior to cutting. 3. Method according to claim 2, characterized in that the bar (14; 15; 45; 46; 47; 60; 74; 75) being fixed on the guide (8) and extending at least partly projecting in front of said guide with respect to the advancing direction of the cut, inserting the bar (14; 15; 45; 46; 47; 60; 74; 75) into the hole (10; 11; 19; 20; 21; 22; 23; 24; 25; 72; 73) previously and as and when cut. 4. Method according to claim 2, characterized in that the rod (14; 15; 45; 46; 47; 74/75) is inserted completely into the orifice (10; 11; 19/20; 21; 22; 23; 24; 25; 72; 73) before cutting. 5. Method according to claim 2, characterized in that the bar (14; 15; 45; 46; 47; 60; 74/75) being fixed on the guide (8) and projecting behind said guide relative in the direction of advance of the cut, the rod is inserted into the orifice (10; 11; 19; 20; 21; 22; 23; 24; 25; 72; 73) as and when cutting. 6. Method according to claim 1, characterized in that the steps of drilling the orifice (10; 11; 19; 20; 21; 22; 23; 24; 25; 72; 73) and cutting the room simultaneously. 7. Method according to any one of the preceding claims, characterized in that it takes the forces exerted on the guide (8) during cutting by mechanical contact between the guide and the bar (14; 15; 47, 60, 74, 75). 8. Method according to any one of the preceding claims, characterized in that the determined distance between the guide (8) and the bar is calculated so that the cross section of the guide and the cross section of the bar (14; 5; 46; 47; 60; 74; 75) are at least partially intersecting. 9. Method according to any one of the preceding claims, characterized in that the hole (10; 11; 19; 20; 21; 22; 23; 24; 25; 72; 73) is drilled centrally on the line. (5) cutting. 10. Method according to any one of the preceding claims, characterized in that at least two holes (10; 11; 19; 20; 21; 22; 23; 24; 25; 72; 73) guide and is introduced at least two corresponding stiffening rods (14; 15; 45; 46; 47; 60; 74; 75). 11. The method of claim 10, characterized in that the orifices (10; 11; 19; 20; 21; 22; 23; 24; 25; 72; 13) and the bars (14; 15; 45; 46; ; 60; 74; 75) are at least partly arranged to be located on either side of the line (5) of section. 12. Method according to any one of the preceding claims, characterized in that the bar (14; 15; 45; 46; 47; 60; 74; 75) comprises at least one cylindrical portion. 13. Method according to any one of the preceding claims, characterized in that the cutting path changing at least once direction, the change being effected on a given area, it stiffens the guide (8) close and / or in contact with said determined zone. Method according to one of the preceding claims, characterized in that the bar (14; 15; 45; 46; 47; 60; 74; 75) is greater than or equal to the length of the cut in the direction normal. 15. Method according to any one of the preceding claims, characterized in that stiffens the guide (8) by contact with the bar via at least one slider (63, 64) sliding. 16. Method according to any one of the preceding claims, characterized in that the means (7) for cutting comprise at least one cutting plate (32) projecting from a side face of the support (9). 17. Device for cutting a workpiece in a block (1) of metallic or composite material along a line (5) of cut having a determined trajectory, comprising cutting means (7) comprising a support (9) flexible and / or articulated extending along said path, and a guide (8) of said support having said determined trajectory, characterized in that it comprises means (58) for piercing at least one orifice (10; 11; 19 20; 21; 22; 23; 24; 25; 72; 73) passing through the block (1) in a direction normal to the determined path on or at a predetermined distance from the cutting line (5), a bar ( 14; 15; 45; 46; 47; 60; 74; 75) of stiffening arranged to cooperate with said orifice, and to take up the forces exerted on the guide (8) by gravity and by said blank, when the stiffening bar is inserted into the hole. 18. Rigidized cutting guide of a workpiece in a block of metal or composite material along a line (5) of section having a determined trajectory, arranged to collaborate with cutting means (7) comprising a support (9) flexible and or articulated extending along said path, characterized in that it comprises at least one bar (14; 15; 45; 46; 47; 60; 74; 75) of stiffening suitable for being introduced into an orifice ( 10; 11; 19; 20; 21; 22; 23; 24; 25; 72; 73) previously pierced in the block (1), of taking up the forces exerted on the guide (8) by gravity and by said cutting. 19. Rigid cutting guide according to claim 18, characterized in that the bar (14; 15; 45; 46; 47; 60; 74; 75) is fixed to the guide (8). 20. stiffened guide according to one of claims 18 and 19, characterized in that it comprises a plurality of bars (14; 15; 45; 46; 47; 60; 74; 75) rigidif ication disposed on either side of the guide (8).