EP0673714A1 - Method and apparatus for deburring and chamfering hole edges through a tube bundel supporting panel - Google Patents

Abstract

The technique includes finishing the holes (2) formed in a plate (1), the holes being intended to receive a series of parallel tubes (3) in a regular pattern. Each hole is larger than the tube to be supported, but includes at least three contact surfaces (4) which project inwards in order to support the tube. In order to smooth and bevel the edges of the holes, partic. the contact surfaces, a rotary brush is moved over the plate surface. The brush moves along a series of parallel lines (5a,5b,5c), each of which forms a tangent to a selection of contact surfaces. By means of a sequence of passes over the plate, all surfaces may be smoothed.

Description

The invention relates to a method and a device for deburring and chamfering the edges of holes passing through a plate for holding a bundle of tubes.

In the manufacture of heat exchangers, in particular steam generators of pressurized water nuclear power stations, large perforated plates are produced for fixing and supporting the bundle of tubes of the heat exchanger.

The steam generators of pressurized water nuclear reactors consist of a large envelope of generally cylindrical shape inside which is disposed a bundle of small diameter tubes tightly fixed in a tubular plate at each of their extremities; these tubes have a vertical path towards the inside of the envelope of the steam generator over a great length and are bent with a certain curvature at their upper part.

The primary water flows through the bundle tubes and secondary water is introduced into the envelope of the steam generator and heats up and vaporizes on contact with the outside surface of the tubes; the vapor is then recovered by the secondary circuit of the reactor.

The vertical parts of the bundle tubes must be kept in position in relation to each other, so that the cross-sections of the tubes form regular networks in planes perpendicular to the axis of the exchanger.

To keep the tubes in position, use is made of spacer plates arranged with a certain spacing according to the height of the heat exchanger. These spacer plates are drilled so as to comprise a network of through holes intended to receive the tubes of the bundle, so that these tubes are arranged in a regular network in the cross sections of the exchanger.

To allow circulation of the secondary fluid in the vertical direction and to avoid deposits of corrosive material in the contact zones between the tubes and the spacer plates, it is necessary to provide holes of more or less complex shapes in the plates- spacers to ensure both the geometric positioning and the effective mechanical maintenance of the tube, the circulation of the secondary fluid and to prevent the accumulation of impurities likely to be present in this fluid. The through holes of the spacer plates each have at least three bearing surfaces of a bundle tube distributed around the hole so as to maintain the tube in all transverse directions as well as radial peripheral recesses ensuring the passage of the coolant around the tube received inside the hole.

The holes may for example have three bearing surfaces and three radial extensions between the bearing surfaces, distributed at 120 ° around the axis of the hole along which the tube is engaged. The holes are then called trifoliate openings.

The holes may also have four bearing surfaces and four radial extensions between the bearing surfaces arranged at 90 ° from each other around the axis of the hole along which the tube is engaged.

The holes are then called quadrifoliated openings.

These holes of more or less complex shape passing through the spacer plates right through are made by machining methods such as drilling, reaming, possibly broaching. The broaching is carried out after drilling the plate to produce a network of pilot holes.

The holes produced by mechanical machining generally include, at the faces of the plate, sharp corners or burrs formed by repelled metal, so that it is necessary to deburr and / or chamfer the edges of these holes on the faces of the spacer plate.

Indeed, the tubes of the bundle which are introduced by pushing in the axial direction inside the holes have a very high quality surface condition and must not undergo any deterioration or scratch, at the time of assembly of the bundle. Scratches on the outside surface of the tubes can constitute cracking and rupture initiations of the tubes in the steam generator in service.

It is therefore necessary, before carrying out the insertion of the tubes and the mounting of the bundle, to carry out a finishing machining on the edges of the holes crossing the spacer plates, to eliminate the burrs and round the sharp angles of these edges of holes.

In the case of a network of holes made by broaching, the face of the spacer plate through which the spindle penetrates has sharp angles and the face of the spacer plate through which the pin emerges has burrs along the edges of the holes .

In FR-A-2,472,961 filed on January 4, 1980 by the company FRAMATOME, a device has been proposed for deburring and chamfering the holes of a perforated plate which comprises a brush rotatably mounted on a carriage around a axis of symmetry arranged parallel to the plate and movable in a direction perpendicular to the plate. The carriage is mounted on a movable support in a first direction parallel to the plate, so that it can move in a second direction parallel to the plate.

It is thus possible to carry out the scanning of the entire surface of the plate by the brush driven in rotation about its axis.

The brush which includes bristles of steel or synthetic fibers possibly associated with an abrasive makes it possible to deburr and / or chamfer the edges of the holes with which the fibers come into rubbing contact, during the displacement of the brush parallel to a face of the plate, with some penetration in a direction perpendicular to the plate.

However, examination of the edges of the holes after a deburring or chamfering operation shows that the chamfers produced by the brush do not have a regular and constant shape for all of the hole edges of the plate. In addition, brushing is liable to repel metal from the edge of the plate holes or metal burrs, so that the edges of the plate holes have parts protruding from the flat surface of the plate on which the holes are through.

It is desirable that the chamfers of the edges of the holes have, in a section through a plane passing through the axis of the hole, a continuous rounded shape between the face of the plate and the interior surface of the hole, with no projecting part relative to the face of the plate or relative to the inner surface of the hole.

If the hole edges of the plate are not properly chamfered or have residual burrs at the support surfaces of the bundle tubes, the bundle tubes may be damaged, for example by scratching their surface, at the when they are inserted into the holes in the spacer plate.

The bearing surfaces of the bundle tubes which are arranged at the periphery of the holes in the spacer plates generally have a substantially planar shape. Due to the arrangement of the holes crossing the spacer plate according to a regular network, the holes constitute rectilinear rows in which the axes of the aligned holes are arranged in a plane perpendicular to the faces of the plate.

The centers of the bearing surfaces of the holes constituting a row are arranged and aligned in planes parallel to the planes containing the axes of the aligned holes.

In the case of trifoliate-shaped openings arranged in a triangular mesh network, the bearing surfaces of the tubes, inside the holes, are arranged in three families of planes whose traces on the faces of the plate are between they angles of 120 °.

In the case of quadrifoliated openings arranged in a square mesh network, the bearing surfaces of the tubes inside the holes are arranged in two sets of planes parallel to each other, directed at 90 ° one of the 'other.

Until now, no deburring and chamfering process has been known which makes it possible to obtain chamfers of regular shape without pushing metal outside the faces of the plate, on all the bearing surfaces of the tubes inside the holes.

The object of the invention is therefore to propose a method of deburring and chamfering the edges of holes passing through a plate for holding a bundle of tubes, arranged in a regular network and each comprising at least three bearing surfaces d '' a tube of the bundle, the bearing surfaces of all the holes in the plate being located in planes perpendicular to the faces of the plate and parallel to the axes of the holes, in each of which are arranged in an aligned manner, according to a rectilinear direction, a set of bearing surfaces of a rectilinear row of network holes, the method consisting in moving at least one rotary brush around an axis parallel to the plate, so as to sweep at least one face of the plate and to obtain edges of holes free of burrs and comprising chamfers of regular shape without repelled part in outside the planes of the faces of the plate.

For this purpose, the deburring and chamfering of the edges of the holes is carried out in successive rectilinear rows and, for each of the rectilinear rows, the brush has its axis of rotation parallel to a plane containing a row of bearing surfaces. , following a rectilinear trajectory parallel to the plane of the row of bearing surfaces.

We will now describe, with reference to the appended figures, by way of nonlimiting example, an embodiment of a deburring and chamfering device according to the invention used for deburring and leveling d '' a spacer plate of a steam generator of a pressurized water nuclear reactor.

Figure 1 is a plan view of a portion of a spacer plate according to a first embodiment having trifoliate-shaped openings.

Figure 2 is a plan view of part of a spacer plate according to a second embodiment having openings of quadrifoliated shape.

Figure 3 is a general top view of a deburring and chamfering station for implementing the method according to the invention.

FIG. 4 is a schematic elevation view of the deburring and chamfering station shown in FIG. 3.

Figure 5 is an elevational view of a device for performing the positioning of the spacer plate.

FIG. 6 is a front view in elevation along line 6 in FIG. 7 of a brushing group of a deburring and chamfering device of an installation as shown in FIGS. 3 and 4.

Figure 7 is a side elevational view along 7 of Figure 6, of the brushing group in the active position.

In FIG. 1, we see a part of a spacer plate 1 of a steam generator of a pressurized water nuclear reactor intended to maintain the tubes of the bundle of the steam generator, according to a regular network, in a transverse plane of the beam.

The plate 1 is constituted by a completely flat steel plate of circular shape having a diameter of the order of four meters.

The plate 1 is crossed by openings 2 (several thousand) arranged in a regular network and making it possible to maintain the tubes 3 of the bundle in a regular arrangement. In the case of the plate shown in Figure 1, the centers of the circular sections of the tubes 3 constituting the intersections of the axes of the tubes with the plane of the figure constitute a triangular mesh network. The openings 2 allowing the passage and the maintenance of the tubes have, in this embodiment, a tri-leaf or three-lobed shape, each of the openings 2 comprising three extensions of radial direction 2a, 2b, 2c around the tube 3, in directions located at 120 ° from each other, around the axis of the tube.

Between any two successive radial extensions of an opening 2, the wall of the opening comprises a part 4 of substantially planar or cylindrical shape coaxial with the opening 2, arranged in the thickness direction of the plate 1, that is to say in the axial direction of the tubes 3.

The three flat surfaces 4a, 4b, 4c of the wall of an opening 2 which are arranged at 120 ° around the axis of a tube 3 constitute bearing or carried surfaces of the tube 3 making it possible to keep it at inside the opening 2, in a perfectly centered position, that is to say so that the axis of the tube 3 and the axis of the opening 2 are coincident.

In this way, when the tube 3 is in place inside the opening 2, the three radial extensions 2a, 2b, 2c of the opening 2 constitute passages for crossing the plate 1 around the tube 3. These feed-through passages allow the circulation of the steam generator feed water coming into contact with the outer surface of the tubes 3, during its circulation in the vertical direction and from bottom to top inside the envelope of the steam generator.

The high temperature primary water from the nuclear reactor vessel and the feed water circulate outside the tubes and in contact with their external surface. In this way, the feed water is heated and then vaporized by heat exchange through the wall of the tubes 3 with the primary water.

The bearing surfaces 4 of the tubes 3 inside the openings 2 are arranged in planes perpendicular to the planar faces of the plate 1 and aligned inside these planes in rectilinear directions which can be represented in FIG. 1 , by the traces of the plans containing the bearing surfaces 4 of the tubes, on the faces of the plate 1.

In the case of the embodiment shown in FIG. 1 (triangular network of three-lobed openings), there are three directions 5a, 5b and 5c making between them angles of 60 ° which correspond to the directions of alignment of the tube bearing surfaces 4 of the openings 2. The planes in which these bearing surfaces 4 are arranged constitute three families of parallel planes the traces of which are all mutually parallel and parallel respectively to directions 5a, 5b and 5c making between them angles of 60 °.

The trace planes 5a, 5b, 5c are parallel to planes in which the axes of a set of openings 2 are arranged which are aligned in a direction parallel to 5a, 5b or 5c. However, the directions 5a, 5b, 5c of the aligned bearing surfaces do not correspond to the main directions of the rows of openings 2 or of tubes 3.

FIG. 2 shows a second embodiment of a spacer plate 1 'for holding the tubes 3' of the bundle of a steam generator of a pressurized water nuclear reactor.

The openings 2 'passing through the plate 1' are arranged in a square mesh network and are produced in a quadrifoliated or quadrilobed form, each of the openings 2 'comprising four extensions of radial direction 2'a, 2'b, 2'c, 2'd arranged at 90 ° to each other around the axis of the tube 3 '.

The radial direction extensions 2 ′ a, 2 ′ b, 2 ′ c, 2 ′ of the openings 2 ′ on the periphery of the tubes 3 ′ ensure the passage of the feed water through the spacer plate 1 ′ in the steam generator in service.

Between any two radial extensions 2'a, 2'b, 2'c, 2'd, the surface of the opening 2 'has a flat bearing surface 4'. Each of the openings 2 ′ has four substantially flat bearing surfaces 4 ′ a, 4 ′ b, 4 ′ c, 4 ′ arranged at 90 ° from one another around the axis of the opening 2 ′ along the thickness of the plate 1 ′, that is to say in a direction parallel to the axis of the 2 'openings and 3' tubes. The bearing surfaces 4 'maintain the tubes 3' in a perfectly centered position inside the openings 2 '.

The spans 4 'are contained in two families of planes parallel to each other having traces of direction 5'a and 5'b on the faces of the plate 1'. The directions 5'a and 5'b correspond substantially to the main directions of the rectilinear rows of openings 2 'of the network of the plate 1'.

After having machined the through openings such as 2 and 2 'of a spacer plate such as 1 or 1', it is necessary, before introducing the bundle tubes 3 or 3 'into the openings 2 or 2', eliminating the burrs formed during broaching on one of the faces of the plate and the sharp edges formed on the other face of the plate, on the edge of the openings 2 or 2 '. The deburring operation of one of the faces of the plate and leveling of the other face must result in the production of regular rounded chamfers around the openings 2 and 2 'on each of the faces of the plate and in particular , in the parts of the edges of openings 2 and 2 'corresponding to the flat bearing surfaces 4 and 4'.

It is desirable to make a regular chamfer on all the edges of the openings, so that the chamfered opening edge has no protruding parts with respect to the faces of the plate and inside the opening. This perfectly preserves the flatness of the spacer plate and avoids scratching the tubes at the time of their introduction into the openings passing through the spacer plates to form the bundle.

In the case of a deburring and a chamfering carried out by a complete sweeping of the faces of the plate with a rotating brush, we have been able to observe irregular chamfer shapes and beads of repelled metal, projecting from the faces of the plates, when brushing is carried out without controlling the directions of movement of the brush on the faces of the spacer plate.

Such defects have been observed in the case of plates the chamfering of which has been carried out using a displacement device with a carriage with crossed movements to move a rotary brush on the faces of the spacer plates, in any way with respect to the rows of openings.

In Figures 3 and 4, there is shown an installation for implementing the method according to the invention in which the brushing of the faces of the plate is carried out in directions and under well defined conditions.

The deburring and chamfering installation allowing the implementation of the method according to the invention comprises, inside a workshop 6, a positioner of spacer plates 7, a robot 8 for moving a brushing group and a central vacuum unit 9.

The installation further comprises a control station 10 and a technical room 11 arranged adjacent to the workshop 6. In the control station 10 are arranged a control cabinet 12, a control console 13 of the positioner 7 and of the robot 8, a microcomputer 14 and a printer 15.

In the technical room 11, there is a control cabinet 16 of the robot 8, a control cabinet 17 of the brushing group and electrical power supplies 18.

On the control desk 13 is arranged a box 19 with control buttons making it possible to actuate the positioning device 7 of a spacer plate remotely.

The robot 8 is a robot which can be used to carry out remotely controlled machining or welding operations with movements along any trajectory in space.

Such a robot is constituted by an articulated arm which has six axes of articulation and which rests on the floor of the workshop by means of a support base 8a.

For the implementation of the method according to the invention, the brushing group 20 which will be described in more detail in the following description is fixed to the end part of the arm called the wrist.

The device 7 for positioning the spacer plate comprises a plate 21 constituted by a flat plate carried by an arm 22.

The plate 21 has tapped openings in determined positions in which one can screw positioning and clamping pins of a spacer plate, when this spacer plate is superimposed on the plate 21.

The positioning pins are engaged and screwed into the plate 21 and the spacer plate on which the deburring and chamfering operation is to be carried out is placed on the plate by engaging the positioning pins in the openings of the spacer plates reserved for the passage of tie rods for fixing the spacer plates relative to each other in the steam generator.

The spacer plate is then fixed on the plate, by engagement of clamping pins in openings for passage of tie rods of the spacer plate and screwing of these clamping pins in threaded openings of the plate 21.

As can be seen in FIG. 5, the plate 21 is rotatably mounted around an axis 23 on the arm 22 of the positioning device, the arm 22 itself being integral with a plate 24 rotatably mounted about an axis 25, on the vertical frame 27 of the positioning device 7 which includes support pads and fixing to the ground 26.

The rotation of the plate 24 around the axis 25 makes it possible to rotate the arm 22 around the axis 25 and to orient the plate 21.

The motorization, the guiding and the indexing of the plate 24 are provided for placing the plate 21 in at least one of three positions which correspond to the horizontal position of the plate 21 shown in FIG. 5, to a vertical position of the plate or at a position inclined at 30 ° to the vertical.

The mounting of a spacer plate on the plate 21 can be carried out when the plate 21 is in its vertical position. The spacer plate is brought near the plate 21 in a vertical position suspended from the sling of a lifting means serving the workshop 6. The spacer plate is engaged on positioning pins fixed on the plate 21 and then returned secured to the plate 21 by means of clamping pins. Two positioning pins and four clamping pins are generally used to fix a spacer plate to the plate 21 of the positioning device 7 for the spacer plates.

As can be seen in FIG. 3, it is possible to place on the plate 21 of the positioner 7, a spacer plate having a diameter between a certain minimum value and a certain maximum value. In FIG. 3, the plate 28 shown in solid lines has a minimum diameter and the plate 28 ′ a maximum diameter, depending on the machining possibilities inside the workshop 6.

For example, in the case of spacer plates for steam generators of pressurized water nuclear reactors, a positioner and a robot are provided making it possible to carry out the finishing machining of plates having a diameter of between 2.40 and 4 meters.

In Figure 3, the plates have been shown in a horizontal arrangement.

The finishing machining of the plates to make their deburring and their chamfering by brushing is carried out with the spacer plate inclined 30 ° rearwards with respect to the vertical, so that the face of the plate to be machined is directed towards the robot 8 and towards the control station 10 adjacent to the workshop 6.

It is obvious that the finishing machining of the two faces of the plate can be carried out by turning the spacer plate face to face on the plate 21, after the machining of a first face.

A suction line 29 connected at one of its ends to the central vacuum 9 is disposed above the robot arm 8, so as to have a second through end above the brushing unit 20 at the end of the robot arm 8. It is thus possible to suck up the dust and filings produced during brushing of a spacer plate and to avoid a flight of dust and the fall of filings inside the workshop. finish 6.

As can be seen in FIGS. 6 and 7, the brushing unit generally designated by the reference 20 comprises two brushing assemblies 20a and 20b carried by a support plate 30. The support plate 30 is fixed to the end of the arm of the robot 8 constituting the wrist of the arm.

Each of the brushing assemblies such as 20a and 20b includes a displacement and pressure application plate 31 fixed to the support plate 30, a group motor 32 and a brushing tool 33 which can be rotated by the motor unit 32.

The motor unit 32 comprises an output pinion 34 and the brushing tool 33 comprises a pin 35 integral at one of its ends with a brush 36 of cylindrical shape and at its other end with a pinion 37. A belt notched drive 38 makes it possible to ensure the connection between the output pinion 34 of the motor unit 32 and the pinion 37 of the brushing tool 33.

Each of the motor groups 32 and the associated brushing tool 33 are fixed to a plate 39 of the movement and pressure application plate 31. The plate 39 constitutes a mobile plate which is mounted to move in the direction of the axis 40 on the support plate 30.

Cylinders 43 and 44 mounted on the support plate 30 make it possible to move the plate 39 in the direction of the axis 40, so as to bring the brushes 36 of the brushing tools 33 in the working position in contact with a face of a spacer plate. The jacks also make it possible to exert a determined force on the brushing tools 33, so that the brushes 36 are applied to the face of the plate 28 during machining with a determined pressure to perform the machining of the edges of the holes of the plate.

The jack 43 is a balancing jack making it possible to eliminate the resultant of the weight of the brushing assembly projected onto a plane making an angle of 30 ° with the horizontal plane. The jack 44 is a bearing jack enabling the bearing force to be applied to the brush 36.

The support plate 30 also carries a linear position sensor 41 making it possible to pinpoint the position of the plate 39 on the support plate 30. The detector 41 constitutes a brush wear detector, the indications of which make it possible to recalculate the position of the robot on each trajectory in order to always work with the plate 39 within its planned stroke as a function of wear and whatever the wear of the brush 36 and to signal the need to change the brush 36 to some degree of wear.

The motor unit 32, the pinions 34 and 37, the belt 38 and the spindle 35 of each of the brushing assemblies are arranged in a protective casing.

A suction casing 42 of substantially parallelepiped shape is also arranged around the brushes 36. The casing 42 has an open face at its lower part allowing the brushes 36 to reach the face of the spacer plate during machining.

The housing 42 includes a seal 42a formed in the form of a soft bristle brush which is applied to the upper surface of the spacer plate when the brushing unit is put into service. When the brushing unit moves on the face of the plate during machining, the casing 42 remains in contact with the face of the plate, by means of the flexible seal 42a.

The end of the suction pipe 29 opens into the interior volume of the suction casing 42 in order to suck up the dust or filings produced during the brushing of the spacer plate.

The brushes 36 have a shape of revolution about their axis of rotation which is defined by the axis of rotation of the spindle 35. Preferably, the brushes 36 have a cylindrical shape and are formed by synthetic fibers, such as fibers of nylon with an abrasive such as silicon carbide incorporated therein.

The motorization of the brushing tools 33 is such that the brushes 36 can be driven at a variable speed of rotation, in one direction or the other. It is thus possible to adjust the circumferential brushing speed to an optimal value whatever the degree of wear thanks to the calculation carried out from the measurement carried out by the detector 41, this value generally being between 10 and 20 m / s.

We will now describe, with reference to all of the figures, a deburring and chamfering operation of a spacer plate such as plate 1 shown in FIG. 1 or such as plate 2 shown in FIG. 2 , using the method and the device according to the invention.

To deburr and chamfer a spacer plate after making the through holes, for example by broaching, the plate is taken up by lifting and handling means such as a bridge and moved to the workshop 6, in the vicinity of the device 7 for positioning the spacer plates The plate 21 of the positioning device is placed in its vertical position and the spacer plate is attached and fixed against the plate 21.

The orientation of the plate in its plane is adjusted by rotating the plate 21 around its axis 23, at the end of the arm 22.

The spacer plate is placed so that the street of water, that is to say a diametrical direction strip of the plate not pierced with holes is in a perfectly vertical arrangement.

The vertical diameter and the horizontal diameter of the spacer plate separate it into four quarter plates which define, for all of the two faces of the plate, eight zones in which the deburring and the chamfering of the edges are carried out successively. holes through the plate.

Between two deburring and chamfering operations involving a quarter of one of the faces of the plate, the plate is rotated by a quarter of a turn.

When the plate is in position on the plate of the positioning device, the directions of the plate are followed according to which the brushes of the brushing unit must be moved as well as the other parameters making it possible to define the ideal conditions for scanning of the plate by the brushing device.

In the case of a spacer plate such as the plate 1 shown in FIG. 1 comprising holes 2 of three-lobed shape arranged in a triangular mesh network, the deburring and the chamfering of the edges of holes at the ends of the surfaces 4 of the tubes must be stopped along paths corresponding to the traces such as 5a, 5b and 5c of the planes containing the bearing surfaces of the openings 2.

The paths 5a, 5b and 5c are mutually parallel and arranged at a constant distance substantially equal to the outside radius of the tubes 3, of a theoretical path 45a, 45b or 45c passing through the centers of the openings 2 of the rectilinear row which is produced the machining of a set of flat bearing surfaces.

The parameters defining the scanning of the plate are determined from the theoretical trajectories 45a, 45b and 45c which are themselves defined by their inclination, for example with respect to the vertical diameter of the plate and by the position of the axis of the one of the holes 2.

A second parameter making it possible to determine the scanning conditions consists of the fixed distance between the real trajectories 5a, 5b and 5c and the theoretical trajectories 45a, 45b and 45c

Other parameters make it possible to define the complete extent of the zone of the spacer plate which is pierced with holes in which the finishing machining is carried out (for example the radius of the zone occupied by the holes).

The parameters defining the scanning of the spacer plate are introduced as input data into the microcomputer 14 and are printed on the printer 15. The microcomputer allows, during the machining operations finishing by brushing the plate, managing the control unit 16 of the robot 8, to move the end of the arm of the robot and the brushing unit 20, perfectly, following the paths such as 5a, 5b, 5c; the computer 14 also makes it possible to manage the control cabinet 17 of the brushing assembly 20 and of its means for pressurizing against the plate.

The robot 8 places the brushing unit 20 in an initial position located in a peripheral part of the spacer plate 28, at the end of a path such as 5a, 5b and 5c.

Beforehand, the spacer plate 28 was tilted towards its working position making an angle of 30 ° with the vertical (FIG. 7).

After the central vacuum unit 9 and the brushing unit have been put into operation, the brushing operation for a first quarter of one face of the plate is initiated from the control station and then continues completely. automatic, the steering trajectories 5a, then the steering trajectories 5b, then the steering trajectories 5c being described one after the other by the end part of the arm of the robot 8.

At the end of the path marked by the limits of the area of the plate to be machined, the robot moves the brushing unit in a direction perpendicular to the trajectory, so as to replace the brushing unit along a theoretical trajectory close to the effective trajectory which has just been carried out.

The brushing tool is then shifted in the direction perpendicular to the theoretical trajectory by a distance equal to the offset which has been entered as a parameter of the process.

Optionally, it is possible to make several passages on each of the rectilinear trajectories before proceeding to the next trajectory.

The number of passages per trajectory can range from one to ten.

The brushing unit 20 disposed at the end of the robot arm is placed on the face of the plate, so that the axis of rotation of the brushes 36 which is parallel to the face of the plate, is directed perfectly along the trajectory along which the scanning is carried out.

The direction of rotation of the brushes is chosen so that the brushes bring out the metal shavings or filings from the holes passing through the spacer plate, during the deburring and chamfering operation. The direction of rotation of the brushes is managed as a function of the direction of movement of the brushing unit, by the computer and the process control program.

The parameters determining the process which can be set at the start of the operation and possibly modified during the operation are the support force of the brushes on the face of the spacer plate, this force generally being between 60 and 120 N , the circumferential speed which is generally between 10 and 20 m / s, the linear speed of advance of the brushes along the trajectories which is generally between 20 and 60 mm / s, the number of passages per trajectory and the transverse shifts between the trajectories.

The deburring and chamfering operation is carried out on a quarter of a face of the plate, fully automatically.

After the operation has been carried out on a quarter of a face of the plate, the robot stops and places itself in a recessed position, so that the plate can be turned a quarter of a turn.

The operation continues on a second quarter of the face of the plate.

When the complete brushing of one face of the plate has been carried out, this plate is turned over, the brushing parameters are possibly modified to take account of the fact that the operation on one of the faces of the plate is an operation of 'deburring and chamfering and that the operation performed on the other side of the plate is a surfacing and chamfering operation of the sharp edges of the holes.

Because the brushing conditions are perfectly defined and the brushing is carried out along paths perfectly parallel to the planes of the abutment surfaces of the tubes, deburring and chamfering are carried out so that the chamfers of the edges of the abutment surfaces are all identical, do not have any part projecting from the face of the plate or inside the hole and have a surface of great regularity.

Dust, filings or burrs detached from the plate during brushing are sucked by the central vacuum unit 9, so that these particles do not remain in the broaching zone and do not settle on the plate or on the floor of the 'finishing workshop.

In the case of a spacer plate having trifoliate openings arranged in a triangular mesh network, as shown in Figure 1, brushing is always carried out along a path real (such as 5a) located on the same side of the corresponding theoretical trajectory (such as 45a). Starting from a theoretical trajectory, a single real trajectory is therefore carried out arranged on one side of the theoretical trajectory and offset by a predetermined distance in a direction perpendicular to the trajectories.

In the case of a spacer plate such as the spacer plate 1 ′ shown in FIG. 2 comprising openings of quadrifoliated shape arranged in a square mesh network, the brushing of the plate is carried out according to two families of paths parallel to the trajectories 5'a and 5'b shown in Figure 2.

For the same theoretical trajectory (such as 45'a), two real trajectories 5'a and 5''a are carried out successively on either side of the theoretical trajectory 45'a, the wiping of the plate following the trajectories 5 'a and 5''a being made in different directions.

Similarly, for the same theoretical trajectory 45'b, the scanning is carried out along two trajectories such as 5'b.

In all cases, the scanning of the plate is carried out along trajectories parallel to the plane containing the abutment surfaces of the holes in the plate and so as to achieve successively on an area of the plate, for example a quarter of a face of the plate, brushing the edges of the abutment surfaces, in successive rows corresponding to a rectilinear alignment of holes comprising a set of bearing surfaces arranged in the same plane perpendicular to the plate.

In all cases, the method according to the invention makes it possible to obtain perfect elimination of burrs without pushing back the metal from the edges of holes and perfectly regular chamfers ensuring a continuous connection between the face of the plate and the interior surface of the hole. We thus obtain spacer plates whose two faces are perfectly smooth and free of burrs and sharp angles. Any deterioration of the bundle tubes is avoided during their engagement inside the spacer plates.

The invention is not limited to the embodiments which have been described.

Thus one can imagine using the method according to the invention in the case of spacer plates having a regular network of holes having shapes different from those which have been described and which are arranged according to a different network d '' a triangular or square mesh network. However, the bearing surfaces of the tubes inside the openings of the plates must be located substantially aligned in planes perpendicular to the faces of the plate.

The displacement of the brushing unit on the faces of the plate can be achieved by using a displacement device different from a robot having an articulated arm.

The brushing unit can also be produced in a different manner from that which has been described and comprise a single brush or on the contrary more than two brushes having aligned or parallel axes. The use of a greater number of brushes or of brushes of a greater axial length makes it possible to limit the number of passes required on each of the trajectories and therefore to limit the total time necessary to brush the plate.

It is obvious that the device for positioning the plate can be produced in a different manner from that which has been described and that the brushing of the plate can be carried out on the plate having any inclination relative to the vertical.

The process control and adjustment means can be produced in a form different from that which has been described.

The invention applies generally to any perforated plate whose holes are intended to receive and hold elongated elements such as tubes.

Claims (18)

1.- Process for deburring and chamfering the edges of holes (2, 2 ') passing through a plate (1, 1') holding a bundle of tubes (3, 3 '), arranged in a regular network and each comprising at least three bearing surfaces (4, 4 ') of a tube (3, 3') of the bundle, the bearing surfaces (4, 4 ') of the set of holes (2, 2' ) of the plate (1, 1 ') being located in planes perpendicular to the faces of the plate (1, 1') and parallel to the axes of the holes (2, 2 '), in each of which is arranged in an aligned manner rectilinear direction, a set of bearing surfaces (4, 4 ') of a rectilinear row of holes (2, 2') of the network, the method consisting in moving at least one rotary brush (36) around an axis parallel to the plate (1, 1 '), so as to sweep at least one face of the plate (1, 1'), characterized in that the deburring and the chamfering of the edges of the holes (2, 2 ') in successive straight rows and for each one of the rectilinear rows, the brush (36) is displaced having its axis of rotation parallel to a plane containing a row of bearing surfaces (4, 4 '), following a rectilinear trajectory (5a, 5b, 5c, 5'a , 5'b) parallel to the plane of the row of bearing surfaces (4, 4 '). 2.- Method according to claim 1, characterized in that the brush (36) is moved successively along rectilinear paths constituting at least two sets of paths which are all parallel to a common direction (5a, 5b, 5c , 5'a, 5'b). 3.- Method according to claim 2, in the case of a plate (1) crossed by openings (2) arranged in a triangular network and each comprising three bearing surfaces (4) of a tube (3) characterized by the fact that the brush (36) is moved successively along rectilinear trajectories constituting three sets of trajectories parallel to three directions (5a, 5b, 5c) making between them angles of 60 °. 4.- Method according to claim 2, in the case of a plate (1 ') traversed by holes (2') arranged in a square mesh network and each comprising four bearing surfaces of a tube (3 ' ) arranged at 90 ° around the axis of the hole (2 ') characterized by the fact that the brush (36) is moved successively along paths constituting two sets of paths parallel to two perpendicular directions (5a, 5b) between them. 5.- Method according to any one of claims 1 to 4, characterized in that the rectilinear trajectories of displacement of the brush (36) are determined, from theoretical trajectories (45a, 45'a) passing through the axes of the holes of the row on which deburring is carried out and of a predetermined offset of the trajectory relative to the theoretical trajectory (45a, 45'a). 6.- Method according to any one of claims 1 to 5, characterized in that the support force of the brush (36) on the plate (1, 1 ') is adjusted to a predetermined value. 7.- Method according to any one of claims 1 to 6, characterized in that the circumferential brushing speed is adjusted from the speed of rotation of the brush (36) and the linear speed of advance of the brush (36) along the straight path (5a, 5b, 5c, 5'a, 5'b), at predetermined values. 8.- Method according to any one of claims 1 to 7, characterized in that the wear of the brush (36) is determined by measuring the position of the brush (36) in a direction perpendicular to the plate (1, 1 ', 28). 9.- Method according to any one of claims 1 to 8, characterized in that the direction of rotation of the brush (36) is adjusted as a function of the direction of movement of the brush (36) on the rectilinear trajectory ( 5a, 5b, 5c, 5'a, 5'b). 10.- Device for implementing a deburring and chamfering process according to any one of claims 1 to 9, characterized in that it comprises a robot (8) for moving a unit of brushing (20) along any path in space and control means (14, 16) of the robot (8), so as to move the brushing unit (20) along successive rectilinear paths (5a, 5b, 5c, 5'a, 5'b) parallel to a plane containing a row of bearing surfaces (4, 4 ') of holes (2, 2') of the plate (1, 1 '). 11.- Device according to claim 10, characterized in that the control means (14, 16) of the robot (8) comprise a control module (16) of the robot (8) and a computer (14) operating a robot movement control software (8) as a function of input parameters defined by the shape and arrangement of the holes (2, 2 ') passing through the plate (1, 1'). 12.- Device according to any one of claims 10 and 11, characterized in that it further comprises a module (17) for controlling the brushing unit (20) fixed on the robot (8). 13.- Device according to any one of claims 10 to 12, characterized in that it further comprises a positioning device (7) of the plate (1, 1 ') in a position for machining by the brushing unit (20) fixed on the robot (8). 14.- Device according to claim 13, characterized in that the positioning device (7) comprises a plate (21) for fixing the plate (1, 1 ') in position superimposed on the plate (21), rotatably mounted on an arm (22) around a first axis of rotation (23) perpendicular to the plate (21), the arm (22) being rotatably mounted on a frame (27) of the positioning device (7) around a second horizontal axis (25) and perpendicular to the first axis (23). 15.- Device according to any one of claims 10 to 14, characterized in that the brushing unit (20) comprises at least one brushing tool (33) comprising a spindle (35) carrying the brush (36) and a motor assembly (32) for rotating the spindle (35) and the brush (36) around the axis of rotation of the brush (36) carried by a plate (39) mounted movably in one direction rectilinear (40) on a support plate (30) integral with the end part of the robot (8) and at least one device (43, 44) for moving the movable plate (39) relative to the support plate (30) in the direction (40), to ensure the adjustment of the contact pressure of the brush (36) on the plate (1, 1 '). 16.- Device according to claim 15, characterized in that the spindle (33) carrying the brush (36) is rotated by the motor unit (32), via pinions (33, 37) and d '' a toothed belt (38). 17.- Device according to any one of claims 15 and 16, characterized in that a housing (42) is arranged around the brush (36) and has an open face carrying at its periphery a flexible seal (42a) for its support on the plate (1, 1 ') when the brush (36) is supported. 18.- Device according to any one of claims 15 to 17, characterized in that it comprises two brushing assemblies (20a, 20b) whose brushes (36) have axes of rotation aligned with each other.

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