Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
  • B24B49/00—Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation
  • B24B49/02—Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation according to the instantaneous size and required size of the workpiece acted upon, the measuring or gauging being continuous or intermittent
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
  • B23Q11/00—Accessories fitted to machine tools for keeping tools or parts of the machine in good working condition or for cooling work; Safety devices specially combined with or arranged in, or specially adapted for use in connection with, machine tools
  • B23Q11/0042—Devices for removing chips
  • B23Q11/0075—Devices for removing chips for removing chips or coolant from the workpiece after machining
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
  • B23Q17/00—Arrangements for observing, indicating or measuring on machine tools
  • B23Q17/24—Arrangements for observing, indicating or measuring on machine tools using optics or electromagnetic waves
  • B23Q17/2452—Arrangements for observing, indicating or measuring on machine tools using optics or electromagnetic waves for measuring features or for detecting a condition of machine parts, tools or workpieces
  • B23Q17/2471—Arrangements for observing, indicating or measuring on machine tools using optics or electromagnetic waves for measuring features or for detecting a condition of machine parts, tools or workpieces of workpieces
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
  • B24B3/00—Sharpening cutting edges, e.g. of tools; Accessories therefor, e.g. for holding the tools
  • B24B3/02—Sharpening cutting edges, e.g. of tools; Accessories therefor, e.g. for holding the tools of milling cutters
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
  • B24B55/00—Safety devices for grinding or polishing machines; Accessories fitted to grinding or polishing machines for keeping tools or parts of the machine in good working condition

Definitions

• the present invention relates to grinding machines which, by grinding and with very high precision, allow the finishing of parts generally made of metal or hard material. It relates in particular to cutting machines for strawberries.
• Such machines generally include a control device and a chassis on which are mounted: - a support provided with fixing means intended to carry a workpiece to be ground, - a machining unit comprising a head, a clamping member mounted on the head and intended to carry a grinding wheel, and a drive device intended to rotate the grinding wheel around a first axis of rotation, to ensure the rectification of the part, and - means for guidance, positioning and displacement, arranged on the chassis and cooperating with the control device to move the workpiece and the grinding wheel.
• the precision to be obtained which is of the order of a thousandth of a millimeter, can only be obtained insofar as each part of the machine is itself very precise.
• One of the most delicate points relates to the positioning and tightening of the part to be rectified on its support. This is why it is essential to start by making a calibration allowing to take into account the relative position of the part and the grinding wheel, before undertaking the rectification. Due to the different variable parameters, it is possible that the expected precision is not achieved. The part must therefore be checked and measured. To perform this measurement with the desired accuracy, it is necessary that the room is clean and at room temperature.
• the part is removed from its support, and it is not within tolerances, it is therefore necessary to repeat the operation, including the calibration, without being sure of obtaining the desired result.
• the machine is inactive and cools, so that when it is restarted, its own dimensions have changed and it must be recalibrated.
• document US Pat. No. 6,449,526 proposes having metrology equipment on its chassis, which makes it possible to avoid removing the part from its support and to shorten the measurement time.
• the part is therefore measured on the machine, apparently without removing the lubrication liquid or the abrasive particles, so that the information obtained is unreliable.
• the part cannot be cooled except by the lubrication liquid and is thus at a higher temperature than the so-called ordinary temperature.
• the object of the present invention is to allow a measurement of the rectified part, clean and at a controlled temperature, without it being necessary to remove it from its support.
• the machine comprises, in a known manner, a control device, a chassis and, mounted on this chassis, members comprising: - a support provided with fixing means intended to carry a workpiece, - a machining unit comprising a head, a clamping member mounted on the head and intended to carry a grinding wheel, and a drive device intended to make rotate the grinding wheel around a first axis of rotation, to ensure the rectification of the part, - means of guidance, positioning and displacement, arranged on the chassis and cooperating with the control device, and - metrology equipment intended to measure the part.
• control device is arranged so as to allow setting in motion and stopping the various mobile components of the machine.
• this machine is characterized in that it further comprises a fluid cleaning device comprising a chamber and arranged so as to allow the engagement, in this chamber, of the part carried by its support and its cleaning by means of the fluid, and in that the guiding, positioning and displacement means are arranged so as to ensure a relative displacement of the support with reference to the grinding wheel, the metrology equipment and the device of cleaning.
• the control device brings it opposite the cleaning device and engages it in the chamber in which it is cleaned and dried, the temperature of the cleaning fluid and the operation. drying to ensure the room a controlled temperature.
• the part is then moved to the vicinity of the metrology equipment which controls the dimensions obtained, under conditions as good as for a measurement after removal of its support.
• cleaning equipment such as that described in document US 2002/0168922, which is provided with a tape, carrying a cleaning paste, against which the part to be cleaned is applied.
• Such a solution does not provide sufficient cleaning quality to guarantee the required precision and does not in any way solve the problem of temperature.
• the fluid used is a liquid solvent. It is thus possible to avoid working at high temperature, as required by aqueous cleaning products.
• the cleaning fluid thus participates in warming up the part to be measured.
• nozzles allowing the projection of the solvent on the part are arranged in the cleaning chamber.
• the latter is provided with a window arranged so that the part can be engaged therein and at least one flap cooperating with the member supporting the part for close the window.
• the support is formed of a headstock comprising fixing means intended to carry the part to be rectified, and drive means for rotating the part around a second axis of rotation.
• the guide, positioning and displacement means comprise means for mobilizing the headstock on the chassis, which comprise a base, part of the chassis, a movable mounted tray along a first axis of translation on the base, by means of a first slide-slider assembly, a table pivotally mounted on the plate around a first pivot axis, by means of a pivot member.
• the headstock is mounted mobile on the table along a second, parallel, translation axis at the second axis of rotation, by means of a second slide-slide assembly.
• the machining unit comprises a second head comprising a clamping device intended to carry a grinding wheel, and a driving device intended to rotate the grinding wheel around a third axis of rotation, to ensure a rough outline of the part, before the first group performs grinding.
• the machining unit is pivotally mounted on the chassis around a second pivot axis parallel to the first pivot axis, the passage from one of the heads to the other can be done in a simple, precise and effective.
• the first and third axes of rotation are perpendicular to each other.
• the guiding and positioning of the machining unit are particularly effective thanks to the fact that the guiding, positioning and displacement means comprise a rail in an arc of a circle, the center of which coincides with its pivot axis and sliding shoes on the rail and integral with one of the chassis, the other of the machining group, arranged so as to precisely support the latter in its periphery.
• the metrology equipment comprises a measuring device, and an enclosure in which the measuring device is placed to protect it and which is provided with a window allowing the part to be engaged therein.
• the machine according to the invention advantageously comprises a fairing defining a confined space in which the machining group and the support are located, and equipment arranged to define a differential pressure between the chamber, the enclosure and the confined space, the highest pressure being in the enclosure, lowest pressure in the room. In this way, any pollution on the one hand of the measuring device by the coolant used to rectify the parts is avoided, and on the other hand of the confined space and of the enclosure by the cleaning.
• FIG. 1 shows, in perspective, a machine according to the invention
• FIG. 2 to 6 show, top view, the machine of Figure 1, in different working positions
• - Figures 7 to 9 illustrate a part of the machine shown in Figures 1 to 6, and more particularly a cleaning device which it comprises
• - Figure 10 is a top view of a variant of the machine according to the invention.
• the machine according to the invention shown in perspective in Figure 1 and seen from above in Figures 2 to 6 is intended to cut and grind cutters. It comprises, as can be seen very particularly in FIGS. 1 and 2, a base 10 made of weighted cast iron of a concrete-polymer mixture which is resistant to vibrations and which is thermally stable. Its upper face includes a central zone surrounded by a channel 12 intended to allow the circulation of a lubrication and cooling liquid.
• the central zone of the base 10 carries a table 14 made of cast iron.
• a pillar 16, adjacent to the table 14, is also mounted on the base 10.
• the base 10, the table 14 and the pillar 16 together form a frame 18 serving as a support for the various functional parts of the machine.
• the table 14 carries a machining group 20 comprising a plate 22 on which are mounted two rotating heads 24 and 26, respectively around axes AA and BB which are perpendicular to each other, and each provided with a clamping member identified by the letter a and of a drive member schematically represented in b.
• These organs can be constituted by electrospindles such as those manufactured by the Renaud (Switzerland) or SMP2 (France) houses.
• the clamping members 24a and 26a respectively carry a cutting wheel 28 comprising two discs 28a and 28b, and a profiling wheel 30.
• the plate 22 is pivotally mounted on the table 14, around a pivot axis C-C identified by the letter ⁇ , perpendicular to the plane of the table 14 and to the axes A-A and B-B. It is connected to the heads 24 and 26 by slide-slide assemblies, not visible in the drawing, which allow translational movements along axes respectively parallel to A-A and B-B. This structure makes it possible to successively bring the grinding wheels 28 and 30 into contact with the cutter, as will be explained below.
• the pillar 16 carries a headstock 32 comprising a clamping member 32a, for example a cleat with an ISO 50 body, in which is engaged the blank of a cutter 34 intended to be cut and profiled, and a drive member 32b arranged to rotate the clamping member 32a and, with it, the cutter 34 around an axis DD parallel to the plane of Figures 2 to 6.
• the headstock 32 is mounted on the pillar 16 via a table 36 ( Figure 1) sliding along an axis EE parallel to the plane of Figures 2 to 6, and which is perpendicular to the axis DD when the headstock 32 is in the working position with the machining group 20.
• the table 36 carries a plate 38 rotating around an axis FF perpendicular to the plane of the drawing and identified by the letter F.
• This plate 38 carries the doll 32, with the interposition of a slide-slide assembly allowing the doll to move along an axis parallel to the DD axis.
• the slide-slide assemblies providing guidance during the translational movements are advantageously fitted with rails and recirculating roller skids of the type sold by the company INA (Germany). These movements are generated by digital motors with high resolution encoder, driving a ball screw with four contact points, like those produced by the house Steinmeyer (Germany) via or not via a reduction with toothed belt. Control of movement is done by an Heidenhain (Germany) incremental ruler of high precision and pressurized.
• control device 39 schematically represented in FIGS. 2 and 3, as used in numerically controlled machines, which includes a computer in which is recorded a program established to define the different movements to be made, for example an order of the NUM 1050 type, provided with specialized software of the NUMROTOplus® type, for example presented in the publication NUMROTOplus Flash N0 6 (April 2003).
• the part of the machine which has just been described makes it possible to ensure the essential function, namely the cutting of the cutter, which consists in forming a blank of the tool to be produced, then in profiling it to give it its final shape. It is possible to make both disc type and bar type cutters, in particular with hemispherical end.
• the first operation consists in cutting the clearance grooves by means of the cutting wheel 28, the disc 28a providing the roughing, the disc 28b finishing. These discs are mounted in a row on a cleat.
• the grooves can be either straight or helical, left or right.
• the profiling is done by means of the grinding wheel 30, by sweeping, by sweeping with beat or by logarithmic calibration.
• the reference for producing the profiles is defined by aligning the radial edge of the grinding wheel 30 on the axis CC of pivoting of the plate 22. This can be done by moving the headstock 32 along the axis EE. The centering of the grinding wheel 30 is checked by measuring the attack on a control plate replacing the cutter 34 on the headstock 32. Because the machining group has two independent heads, it is not necessary to change the grinding wheel during work. In addition and if necessary, a robot could be used to change grinding wheels and / or parts.
• the drive means can be adapted to the power that they must provide, for a particular application.
• the grinding wheels 28 and 30 and the milling cutter 34 are watered by means of solid oil arriving at high flow rate, or of a synthetic oil such as those sold by the house EQUALIT (Italy).
• the oil is recovered by the channel 12 and led to a recycling installation which has not been shown and in which the oil is refrigerated and purified by centrifugation.
• the other parts of the machine allow in situ measurement of the cutter 34. It is more particularly a cleaning device 40 and metrology equipment 42, which are fixed and / or adjoining the base 10.
• the cleaning device 40 will be described in more detail with reference to FIGS. 7 to 9. It is disposed in the immediate vicinity of the base 10 and comprises a chamber 43 and a window 44 opening into the chamber 43 and making it possible to introduce the cutter 34 .
• the window 44 is arranged so that the cutter 34 can be introduced into the chamber 43 by movements of the headstock 32, rotation around the axis F-F and translation along the axis D-D.
• the chamber 43 is movable in translation, so that it can be advanced towards the headstock 32.
• the metrology equipment 42 comprises an optical measuring device 45, for example of the type with two high-resolution CCD cameras, marketed by the company Tecnogamma (Italy) under the reference 14. It further comprises a measurement cavity defined by an enclosure 46, partially removed in the figures and in which there is an overpressure ensuring that no particle of abrasive, lubricant or cleaning product enters it.
• the measuring device 45 is arranged so that after having removed the headstock 32 from the chamber 43 of the cleaning device 40, having made it rotate around the axis FF, then translate on the axis DD, the cutter 34 can engage in the cavity that defines the enclosure 46, to make a measurement.
• the control device 39 comprises a second computer which collects the information obtained thanks to the measuring device 45. This information is compared with the limits defined initially.
• FIGS. 2 to 6 represent the machine in its different working positions.
• the first operation consists in fixing a blank of cutter 34 in the clamping member 32a of the headstock 32.
• This operation can be done either manually, or by means of an automaton or a robot programmed for this purpose.
• the blank is then cut in the position illustrated in FIG. 2.
• the headstock 32 and the plate 22 are placed so that the grinding wheel 28 cooperates with the cutter 34 to cut it.
• the head 24 carrying the grinding wheel 28 is moved along the axis AA.
• the plate 22 rotates around the axis CC, then the head 26 is translated along the axis BB so as to bring the grinding wheel 30 in the vicinity of the cutter 34, as indicated in FIG. 3.
• the cutter 34 is then profiled, that is to say that the shape of the teeth of the cutter is rectified.
• the headstock 32, the plate 22 and the heads 24 and 26 are controlled by the program stored in the control device 39.
• the headstock 32 rotates around its axis FF, until the cutter 34 is brought opposite window 44, then translates along axis DD (FIG. 4).
• the chamber 43 is also moved (FIG. 5), so that the milling cutter 34 penetrates therein to be cleaned therein according to a process which will be specified with reference to FIGS. 7 to 9.
• the cutter 34 being cleaned it is removed from the chamber 43, by movements in the opposite direction of the chamber 43 and of the headstock 32.
• the latter pivots around the axis FF so that the cutter 34 is located opposite the metrology equipment 42.
• a new translation along the axis DD brings the cutter 34 into the cavity of the enclosure 46, so that the measuring device 45 can perform the measurements, for example by transmitted-light or episcopia.
• the information entered by the cameras of the device 45 is processed by the control device 39 which determines whether the shape of the cutter 34 is within the tolerances or whether it must be corrected. In the first case, it is removed from the clamping member 32a. Otherwise, the headstock 32 is brought back by rotation and translation into the position illustrated in FIG. 3, for retouching by means of the grinding wheel 30, controlled by the device 39. This retouching is carried out according to the same cycle as described above. As soon as the tolerances are reached, the part can be removed.
• the control device delivers a control protocol establishing the compliance of the cutter with the defined requirements.
• the cutter 34 does not need to be removed from the clamping member 32a to be able to control it. It is therefore possible to guarantee much better working conditions, making it possible to avoid recalibration after the removal and then the installation of the cutter 34.
• the cleaning device 40 comprises, in addition to the chamber 43, a retention tank 50 in which is stored a cleaning solvent 52, for example of the type sold by the house of Houghton (Italy), the level of which is represented by a line interrupted.
• a coil 53 connected to a thermal installation not shown in the drawing, ensures that the solvent 52 is maintained at a stable temperature, which guarantees that at the outlet of the chamber 43, the part will have the appropriate temperature.
• a pipe 54 allows the passage of the solvent 52 between the tank 50 and the chamber 43, the circulation being ensured by a pump 56 which sucks the solvent 52 in the tank 50 and sends it under pressure to the room 43.
• a filter 58 is connected to the pipe 54, eliminating the particles in suspension.
• a valve 59 controls the circulation of the solvent 52 in the piping 54.
• a distiller 60 can advantageously be connected to the tank 50, to ensure the regeneration of the solvent 52.
• the chamber 43 is pierced by the window 44 whose periphery is defined by two flaps 62 mounted sliding on the walls of the chamber 43.
• Control means, schematically represented at 64 are connected to the control device 39 and ensure the sliding of the shutters 62 to open and close the window 44.
• a nozzle ramp 68 connected to the piping 54, is fixed to the interior wall of the chamber 43.
• the latter also carries a suction system 70 which provides vacuum inside the chamber 43. It comprises a vacuum cleaner 72 with an explosion-proof motor, and a filter 74 with activated carbon, which makes it possible to avoid the emission of solvent outside the chamber 43.
• Figure 9 shows, in sectional view, the chamber 43 inside which is the cutter 34, fixed on the headstock 32 and more particularly its member tightening 32a.
• the latter comprises a mandrel 32c which extends to the level of the flaps 62.
• the flaps 62 are applied against the mandrel 32c, so as to make the chamber 43 practically sealed.
• the pump 56 is then actuated and the solvent 52 is sprayed onto the cutter 34 through the nozzles of the ramp 68.
• the chamber 43 is under pressure so as to prevent solvent 52, in the form liquid or gaseous, do not come out.
• the mandrel 32c rotates slowly, so that the solvent is sprayed regularly over the entire surface of the cutter 34. In order to reduce the cleaning time, it is possible to have several ramps inside the chamber. 43.
• the cutter 34 After the spraying of solvent 52 has been stopped, the cutter 34 remains for a while inside the chamber 43 to dry it.
• the drying time depends on the structure of the cutter 34 and the solvent used. It can be defined empirically.
• the shutters 62 are then opened so that the chamber 43 on the one hand, the headstock 32 on the other hand slide and move away from one another.
• the headstock 32 can then pivot around its axis F-F, to bring the cutter 34 opposite the metrology equipment 42.
• a jet of air at controlled temperature can be projected on the cutter after it has been taken out of the chamber 43 and until during the measurement operation.
• This embodiment differs essentially from that described above by the structure of the table 14, the machining group 20 and its plate 22.
• the upper elements of the machine have been torn off , so as to make essential hidden parts visible.
• the plate 22 is pivotally mounted on the table 14 by means of a rail 80 in an arc of a circle concentric with the axis C-C and pads 82 cooperating with the rail to support and guide the plate 22 in its periphery.
• the pads 82, carried by the plate 22 are of the ball recirculation type.
• a protection 84, integral with the plate 22, covers the rail 80 and passes into a clearance that includes the pillar 16. The latter therefore forms a bridge above the rail 80 and the protection 84. Thanks to the protection 84, the rail and the pads are protected from lubricant and abrasive particles. With this particular structure, the table 14 can support large loads while retaining its high precision.
• the fairing is provided with openings arranged facing the cleaning device and the metrology equipment to allow access to the cutter 34. Removable shutters close these openings outside times when access must be made possible to the room and the enclosure in which cleaning and measurement are carried out respectively.
• the confined space defined by the fairing is in depression with respect to the enclosure of the metrology equipment and in overpressure with respect to the cleaning chamber. In this way, pollution is avoided, especially at level of the measurement enclosure, but also in the confined space.
• the fairing includes, of course removable parts which allow access to the confined space, to allow adjustment and cleaning of the machine.
• the machine is intended for manufacturing precision cutters, by roughing, finishing and then profiling operations, which is equivalent to a grinding operation.
• the same concept is applicable to other operations with the same purpose, that is to work a part with great precision, by rectification.
• the workpiece may or may not be fixed.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Grinding Of Cylindrical And Plane Surfaces (AREA)
• Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)

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• 2003
  • 2003-10-15 EP EP03405741A patent/EP1524072A1/de not_active Withdrawn
• 2004
  • 2004-10-13 EP EP04761963A patent/EP1677945A1/de not_active Withdrawn
  • 2004-10-13 WO PCT/CH2004/000623 patent/WO2005035188A1/fr active Application Filing

Non-Patent Citations (1)

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