EP0673714B1 - Method 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 for deburring and chamfering edges of holes passing through a plate holding a bundle of tubes.

In the manufacture of heat exchangers, in particular generators of steam from pressurized water nuclear power plants, we realize large perforated plates for fixing and support of the heat exchanger tube bundle.

Steam generators of pressurized water nuclear reactors consist of a large envelope of general shape cylindrical inside which is arranged a bundle of tubes small diameter tightly fixed in a tubular plate to each of their ends; these tubes have a vertical path inward of the steam generator jacket over a long length and are folded with a certain curvature at their upper part.

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

The vertical parts of the bundle tubes must be maintained in position relative to each other, so that the cross sections tubes constitute regular networks in perpendicular planes to the axis of the exchanger.

To keep the tubes in position, we use spacer plates arranged with a certain spacing according to the height of the heat exchanger. These spacer plates are drilled so as to have 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 corrosive deposits in the contact areas between the tubes and the spacer plates, it is necessary to provide more or less shaped holes complex in the spacer plates to ensure the both geometric positioning and mechanical support efficient tube, secondary fluid circulation and to prevent the accumulation of impurities likely to be in this fluid. The through holes of spacer plates each have at least three support surfaces of a beam tube distributed around the hole so as to maintain the tube in all transverse directions as well as recesses radial devices ensuring the passage of the cooling 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 according to which the tube is engaged. The holes are then called trifoliate openings.

The holes can also have four bearing surfaces and four radial extensions between the bearing surfaces arranged at 90 ° to 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 crossing the spacer plates right through are produced by machining processes such as drilling, the bore, possibly the pinout. The pinout is made after drilling the plate to create a network pilot holes.

The holes made by mechanical machining include generally, at the faces of the plate, sharp corners or burrs formed by repelled metal, so 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 beam which are introduced by pushing in the axial direction inside holes have a very high quality surface finish and must not be damaged or scratched at the time mounting the harness. Scratches on the outer surface tubes can constitute crack initiators and rupture of the tubes in the generator steam in service.

It is therefore necessary, before carrying out the introduction tubes and mounting the beam, performing finishing machining on the edges of the through holes spacer plates, to eliminate burrs and round off the sharp corners of these hole edges.

In the case of a network of holes made by pinout, the face of the spacer plate through which penetrates the pin has sharp angles and the face of the spacer plate through which the spindle comes out 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 deburring and chamfering plate holes perforated which includes a brush rotatably mounted on a carriage around an axis of symmetry arranged in parallel to the plate and movable in a perpendicular direction to the plate. The carriage is mounted on a mobile support in a first direction parallel to the plate, of so you 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 around its axis.

The brush with bristles made of steel or synthetic fibers possibly combined with an abrasive allows deburring and / or chamfering of edges of the holes with which the fibers come into rubbing contact, while the brush is moving parallel to one side 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 edges of plate holes. In addition, brushing is likely to push metal from the edge of the plate holes or metal burrs, so that the edges of the plate holes have protruding parts relative to the flat surface of the plate on which the holes are through.

It is desirable that the chamfers of the edges holes have, in a section through a passing plane by the axis of the hole, a continuous rounded shape between the face of the plate and the inner surface of the hole, without protruding part relative to the face of the plate or relative to the inner surface of the hole.

In case the edges of the plate holes are not properly chamfered or have residual burrs on the bearing surfaces of the bundle tubes, the bundle tubes can be deteriorated, for example by scratching their surface, 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 shape substantially plane. Due to the arrangement of the holes crossing the spacer plate according to a regular network, the holes constitute rows rectilinear in which the axes of the aligned holes are arranged along 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 aligned hole axes.

In the case of trifoliate openings arranged in a network with triangular meshes, the bearing surfaces of the tubes, inside the holes, are arranged according to three families of planes whose traces on the faces of the plate make between them 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 90 ° from each other.

In an article in the review "ZWF CIM Zeitschrift für Wissenschaftliche Fertigung und Automatisiertung ", page 492-495 of number 9 of September 1990, a deburring device was described comprising a robot for movement of a brushing unit along any path in space and robot control means. The device described is however not suitable for deburring a spacer plate.

We did not know until now of deburring and chamfering process allowing to obtain chamfers of regular shape without embossing of metal outside the faces of the plate, on all surfaces support tubes inside the holes.

The object of the invention is therefore to propose a deburring process and for chamfering the edges of holes passing through a retaining plate bundle of tubes, arranged in a regular network and each comprising at least three bearing surfaces of a bundle tube, the bearing surfaces of all the holes in the plate being located in perpendicular planes to the faces of the plate and parallel to the axes of the holes, in each which are arranged, in an aligned manner, in a rectilinear direction, a set of bearing surfaces of a straight row of holes in the grating, the method of moving at least one rotating brush around an axis parallel to the plate, so as to scan at least one face of the plate and to obtain edges of holes free of burrs and comprising bevels of regular shape without part pushed back outside planes of the faces of the plate.

For this purpose, we deburr and chamfer the edges of holes, in successive straight rows and, for each of the rows straight, we move the brush having its axis of rotation parallel to a plane containing a row of bearing surfaces, following a straight path parallel to the plane of the row of bearing surfaces.

We will now describe, with reference to the attached figures, by way of nonlimiting example, the implementation of the following method the invention of deburring and chamfering a spacer plate of a generator of steam from a pressurized water nuclear reactor.

Figure 1 is a plan view of part of a spacer plate according to a first embodiment comprising shaped openings trifoliate.

Figure 2 is a plan view of part of a spacer plate according to a second embodiment comprising shaped openings quadrifoliate.

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

Figure 4 is a schematic elevational view of the deburring station and chamfering shown in Figure 3.

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

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

Figure 7 is a side elevation view according to 7 of FIG. 6, of the brushing group in position active.

In Figure 1, we see part of a spacer plate 1 of a reactor steam generator pressurized water nuclear intended to ensure the maintenance of the steam generator harness tubes, following a regular network, in a transverse plane of beam.

Plate 1 consists of a plate entirely planar steel of circular shape having a diameter of the order of four meters.

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

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

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

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

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 at through the wall of the tubes 3 with the primary water.

The bearing surfaces 4 of the tubes 3 inside openings 2 are arranged in perpendicular planes to the flat faces of the plate 1 and aligned inside of these planes following rectilinear directions which can be represented in FIG. 1, by the traces of the plans containing the bearing surfaces 4 of 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 directions of alignment of the tube spans 4 of the openings 2. The planes in which these are placed bearing surfaces 4 constitute three families of planes parallels whose traces are all parallel between they 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 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 not to the main directions of the rows of openings 2 or tubes 3.

In FIG. 2, a second mode has been represented. for producing a spacer plate 1 ′ for holding the tubes 3 'of the bundle of a steam generator 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 'having four extensions radial direction 2'a, 2'b, 2'c, 2'd arranged at 90 ° from each other around the axis of the tube 3 '.

The radial direction extensions 2'a, 2'b, 2'c, 2'd of the openings 2 'at the periphery of the tubes 3' ensure the supply water passes through the spacer plate 1 'in the steam generator service.

Between two radial extensions 2'a, 2'b, 2'c, 2'd any, the surface of the opening 2 'has a flat support surface 4 '. Each of the 2 'openings comprises four substantially flat bearing surfaces 4'a, 4'b, 4'c, 4'd arranged at 90 ° to each other around the axis of the opening 2 'depending on the thickness of the plate 1 ', i.e. in a direction parallel to the axis of 2 'openings and 3' tubes. 4 'support spans maintain the 3 'tubes in one position perfectly centered inside the 2 'openings.

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

After machining the through openings such as 2 and 2 'of a spacer plate such as 1 or 1 ', it is necessary, before introducing the tubes of the 3 or 3 'beam in 2 or 2' openings, to realize elimination of burrs formed during broaching on one of the faces of the plate and the sharp edges formed on the other side 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 the other side should result in making regular rounded chamfers around openings 2 and 2 'on each side 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 chamfer regular on all edges of openings, so that the chamfered opening edge has no part projecting from the faces of the plate and inside of the opening. This perfectly preserves the flatness of the spacer plate and avoid scratching the tubes at the time of their introduction into the openings passing through the spacer plates to constitute the beam.

In the case of deburring and chamfering made by a full scan of the plate faces with a rotating brush, we could observe shapes of irregular chamfer and embossed metal beads, projecting from the faces of the plates, when brushing is carried out without checking the directions of displacement of the brush on the faces of the spacer plate.

Such defects have been observed in the case of plates whose chamfering was carried out using a moving device with cross-motion carriage to move a rotating brush on the faces of the spacer plates, in any way compared to rows of openings.

In Figures 3 and 4, there is shown a installation for implementing the process according to the invention in which the brushing of the faces of the plate is made in directions and in well-defined conditions.

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

The installation also includes a control 10 and a technical room 11 arranged so adjacent to workshop 6. In the workstation control 10 are arranged a control cabinet 12, a control panel 13 of the positioner 7 and of the robot 8, one microcomputer 14 and a printer 15.

In the technical room 11 are arranged a control cabinet 16 of robot 8, a control cabinet 17 brushing group and power supplies electric 18.

On the control console 13 is arranged a box 19 with control buttons for operating at distance the positioning device 7 from a spacer plate.

Robot 8 is a robot that can be used to carry out machining or welding operations remotely controlled with movements according to any trajectories in space.

Such a robot is constituted by an articulated arm which has six axes of articulation and which rests on the workshop floor via 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 detail in the following description is attached 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 plate plane carried by an arm 22.

The plate 21 has tapped openings in certain positions in which we can screw positioning and tightening 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 must be carried out the deburring and chamfering is put in place on the plate by engaging the positioning pins, in openings of the spacer plate reserved for the passage of tie rods fixing of the spacer plates one with respect to the other in the steam generator.

The spacer plate is then fixed to the plate, by engagement of clamping pins in spacing plate tie rod openings and screwing these clamping pins into openings threaded plate 21.

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

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

The motorization, guidance and indexing of the tray 24 are provided to place the tray 21 in one at least of three positions that correspond to the horizontal position of the plate 21 shown on the Figure 5, at a vertical position of the tray or at a position tilted at 30 ° from the vertical.

The mounting of a spacer plate on the plate 21 can be achieved when the plate 21 is in its vertical position. The spacer plate is brought to proximity of the plate 21 in a vertical suspended position with the sling of a lifting means serving the workshop 6. The spacer plate is engaged on pins of positioning fixed on the plate 21 then made integral of the plate 21 by means of clamping pins. We generally use two positioning pins and four clamping pins for fixing a spacer plate on the plate 21 of the positioning device 7 of the spacer plates.

As can be seen in Figure 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 certain maximum value. In Figure 3, the plate 28 shown in solid lines has a minimum diameter and the plate 28 'a diameter maximum, depending on the machining possibilities inside from workshop 6.

For example, in the case of spacer plates for steam generators from nuclear reactors to pressurized water, a positioner and a robot are provided allowing to finish plate machining having a diameter 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 achieve deburring and chamfering by brushing is carried out with the spacer plate tilted 30 ° towards the rear relative to the vertical, so that the face of the plate to be machined is directed towards the robot 8 and to control station 10 adjacent to workshop 6.

It is obvious that the finishing machining on both sides of the plate can be made by turning the spacer plate face for face on the plate 21, after the machining of a first face.

A suction line 29 connected to one of its ends at the central vacuum unit 9 is disposed above the robot arm 8, so as to present a second end opening above the unit brushing 20 at the end of the robot arm 8. We can so suck up the dust and filings produced when brushing a spacer plate and avoiding a soaring dust and falling filings to inside the finishing workshop 6.

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

Each of the brushing sets such as 20a and 20b includes a tray for moving and applying pressure 31 fixed on the support plate 30, a group motor 32 and a brushing tool 33 which can be driven in rotation by the power unit 32.

The motor unit 32 includes an output pinion 34 and the brushing tool 33 has a pin 35 integral at one of its ends of a brush 36 of shape cylindrical and at its other end with a pinion 37. A toothed drive belt 38 ensures 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 33 are fixed on a plate 39 of the plate displacement and pressure application 31. The plate 39 constitutes a mobile plate which is mounted movable in the direction of axis 40 on the support plate 30.

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

The jack 43 is a balancing jack allowing to eliminate the resultant of the weight of the whole brushing projected on a plane making an angle of 30 ° with the horizontal plane. The jack 44 is a support jack for applying the pressing force on the brush 36.

The support plate 30 also carries a sensor position linear 41 for precise location the position of the plate 39 on the support plate 30. The detector 41 constitutes a wear detector of the brush whose indications allow to recalculate the position of the robot on each trajectory in order to work always with plate 39 inside its stroke expected according to wear and whatever wear brush 36 and signal the need to change the brush 36 to a certain degree of wear.

The power unit 32, the pinions 34 and 37, the belt 38 and pin 35 of each of the sets of brushing are arranged in a protective casing.

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

The casing 42 has a seal 42a made up in the form of a soft bristle brush which is applied on the upper surface of the spacer plate when commissioning the brushing unit. When movements of the brushing unit on the face of the plate being machined, the housing 42 remains in contact with the face of the plate, via the seal flexible 42a.

The end of the suction line 29 opens into the interior volume of the suction housing 42 to suck up the dust or filings produced while brushing the spacer plate.

Brushes 36 have a form of revolution around 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 made by synthetic fibers, such as fibers nylon with an abrasive such as silicon carbide.

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

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

For deburring and chamfering a spacer plate after making the through holes for example by pinout, the plate is taken in load by lifting and handling means such as bridge and moved to workshop 6, near 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 water street, that is to say a band of diametrical direction of the plate without holes is in a perfectly vertical arrangement.

The vertical diameter and the horizontal diameter of the spacer plate separate it into four quarters of plates which define, for the set of the two faces of the plate, eight zones in which one successively performs deburring and chamfering the edges of holes through the plate.

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

When the plate is in position on the pan of the positioning device, the location is carried out directions of the plate according to which one must move the brushes of the brushing unit as well as the other parameters used to define the ideal conditions for scanning the plate by the device brushing.

In the case of a spacer plate such as the plate 1 shown in Figure 1 having holes 2 of three-lobed shape arranged in a mesh network triangular, deburring and chamfering the edges of holes at the ends of the tube stop surfaces 4 must be carried out according to corresponding trajectories with traces such as 5a, 5b and 5c of the plans containing the support surfaces of the openings 2.

The trajectories 5a, 5b and 5c are parallel between them and arranged at a constant distance substantially equal to the outside radius of the tubes 3, of theoretical trajectory 45a, 45b or 45c passing through the centers of the openings 2 of the straight row of which performs the machining of a set of flat bearing surfaces.

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

A second parameter used to determine the scanning conditions is made up by the fixed distance between the real trajectories 5a, 5b and 5c and the trajectories theoretical 45a, 45b and 45c.

Other parameters allow to define the full extent of the spacer plate area which is drilled with holes in which the machining of finish (for example the radius of the area occupied by the holes).

The parameters defining the scanning of the spacer plate are entered as input in the microcomputer 14 and are the subject of an impression on the printer 15. The microcomputer allows, during finishing machining operations by brushing of the plate, to manage the control unit 16 of the robot 8, to move the end of the robot arm and the brushing 20, perfectly, following the trajectories such that 5a, 5b, 5c; the computer 14 also makes it possible to manage the control cabinet 17 of the brushing assembly 20 and its pressurizing means 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 trajectory such as 5a, 5b and 5c.

Beforehand, the spacer plate 28 was tilted to its working position at an angle of 30 ° with the vertical (figure 7).

After commissioning of the central suction 9 and brushing unit, the operation of brushing a first quarter of one side of the plate is initiated from the control station and then continues fully automatically, the trajectories of direction 5a, then direction trajectories 5b, then the direction trajectories 5c being described one at following the other by the end part of the arm of the robot 8.

At the end of the trajectory 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 following a theoretical trajectory close to the trajectory that has just been achieved.

We then shift the brushing tool in the direction perpendicular to the theoretical trajectory of a distance equal to the offset that was entered as a parameter of the process.

Optionally, several passages on each of the rectilinear trajectories before go to the next trajectory.

The number of passages per trajectory can go 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, be directed perfectly following the trajectory along which we realize the scanning.

The direction of rotation of the brushes is chosen for the brushes remove the shavings or filings metallic holes passing through the spacer plate, during the deburring and chamfering operation. The direction of rotation of the brushes is managed according to the direction movement of the brushing unit, by the computer and the process control program.

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

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

After the operation has been performed on a quarter of a face of the plate, the robot stops and place in a recessed position, so that can rotate the plate a quarter turn.

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

When the complete brushing of a face of the plate, this plate is turned over, the parameters brushing are possibly modified to hold account of the fact that the operation on one side of the plate is a deburring and chamfering operation and that the operation performed on the other side of the plate is surfacing and chamfering of edges vivid holes.

Because the brushing conditions are perfectly defined and brushing is carried out according to trajectories perfectly parallel to the planes of tube stop surfaces, deburring and chamfering are made so that the chamfers of the edges stop surfaces are all identical, do not have no part projecting from the face of the plate or inside the hole and have a surface very regular.

Dust, filings or loose burrs of the plate during brushing are sucked in by the central vacuum unit 9, so that these particles do not do not stay in the pinout area 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 network with triangular meshes, as shown in FIG. 1, brushing is always carried out along a path real (such as 5a) located on the same side of the trajectory theoretical (such as 45a) corresponding. From of a theoretical trajectory, so we perform only one real trajectory arranged on one side of the trajectory theoretical and shifted 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 Figure 2 comprising quadrifoliate openings arranged following a square mesh network, brushing the plate is made according to two families of trajectories parallel to the trajectories 5'a and 5'b shown in the figure 2.

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

Likewise for the same theoretical trajectory 45'b the scanning is carried out along two trajectories such than 5'b.

In all cases, the plate scan is realized along trajectories parallel to the plane containing the abutment surfaces of the plate holes and so as to perform successively on an area of the plate, for example a quarter of a face of the plate, the brushing the edges of the abutment surfaces, in successive rows corresponding to a straight 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 allows perfect elimination of burrs without pushing back the metal from the edges of holes and chamfers perfectly regular ensuring a continuous connection between the face of the plate and the interior surface of the hole. We thus obtain spacer plates whose two sides are perfectly smooth and free of burrs and sharp angles. Avoid any deterioration of the tubes of the beam during their engagement inside the spacer plates.

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

This is how we can imagine using the process according to the invention in the case of spacer plates comprising a regular network of holes having different forms from those which have been described and which are arranged in a different network from a network to triangular or square meshes. However, the surfaces tube support inside the plate openings should be located approximately aligned in planes perpendicular to the faces of the plate.

The movement of the brushing unit on the faces of the plate can be achieved using a device of different displacement of a robot having an arm Speak clearly.

The brushing unit can also be realized in a different way from that which has been described and have only one brush or more than two brushes having aligned or parallel axes. Use of a greater number of brushes or brushes of a greater axial length makes it possible to limit the number of necessary passes on each of the trajectories and therefore of limit the total time required for brushing of the plate.

It is obvious that the positioning device of the plate can be realized in a way different from the one that was described and that brushing of the plate can be done on the plate having an inclination any with respect to the vertical.

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

The invention generally applies to any perforated plate whose holes are intended for receive and maintain elongated items such as tubes.

Claims (9)

1. Process for deburring and chamfering the edges of holes (2, 2') passing through a plate (1, 1') for holding a bundle of tubes (3, 3'), arranged in a regular grid pattern and each comprising at least three bearing surfaces (4, 4') for a tube (3, 3') of the bundle, the bearing surfaces (4, 4') of the set of holes (2, 2') in the plate (1, 1') being located in planes perpendicular to the sides of the plate (1, 1') and parallel to the axes of the holes (2, 2') in each of which is arranged, aligned in a straight configuration, a set of bearing surfaces (4, 4') of a straight row of holes (2, 2') of the grid pattern, the process comprising moving at least one rotary brush (36) about an axis parallel to the plate (1, 1'), so as to sweep at least one side of the plate (1, 1'), characterised in that the deburring and chamfering of the edges of the holes (2, 2') are carried out in successive straight rows and for each of the straight rows the brush (36), having its rotation axis parallel to a plane containing a row of bearing surfaces (4, 4'), is moved along a straight trajectory (5a, 5b, 5c, 5'a, 5'b) parallel to the plane of the row of bearing surfaces (4, 4').
2. Process according to claim 1, characterised in that the brush (36) is moved, successively, along straight trajectories constituting at least two sets of trajectories which are all parallel to a common direction (5a, 5b, 5c, 5'a, 5'b).
3. Process according to claim 2, in the case of a plate (1) drilled with openings (2) arranged in a triangular grid pattern and each comprising three bearing surfaces (4) of a tube (3), characterised in that the brush (36) is moved, successively, along straight trajectories constituting three sets of trajectories parallel to three directions (5a, 5b, 5c) forming angles of 60° between them.
4. Process according to claim 2, in the case of a plate (1') drilled with openings (2') arranged in a square mesh grid pattern and each comprising four bearing surfaces of a tube (3') disposed at 90° about the axis of the hole (2'), characterised in that the brush (36) is moved, successively, along trajectories constituting two sets of trajectories parallel to two directions (5a, 5b) perpendicular to each other.
5. Process according to any one of claims 1 to 4, characterised in that the straight trajectories of movement of the brush (36) are determined on the basis of theoretical trajectories (45a, 45'a) passing through the axes of the holes in the row on which the deburring is being carried out and of a predetermined offset of the trajectory relative to the theoretical trajectory (45a, 45'a).
6. Process according to any one of claims 1 to 5, characterised in that the bearing force of the brush (36) on the plate (1, 1') is regulated to a predetermined value.
7. Process according to any one of claims 1 to 6, characterised in that the circumferential brushing speed is regulated to predetermined values on the basis of the speed of rotation of the brush (36) and the linear speed of advance of the brush (36) along the straight trajectory (5a, 5b, 5c, 5'a, 5'b).
8. Process according to any one of claims 1 to 7, characterised 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. Process according to any one of claims 1 to 8, characterised in that the direction of rotation of the brush (36) is regulated as a function of the direction of movement of the brush (36) along the straight trajectory (5a, 5b, 5c, 5'a, 5'b).

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