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
  • B24B53/00—Devices or means for dressing or conditioning abrasive surfaces
  • B24B53/001—Devices or means for dressing or conditioning abrasive surfaces involving the use of electric current
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23H—WORKING OF METAL BY THE ACTION OF A HIGH CONCENTRATION OF ELECTRIC CURRENT ON A WORKPIECE USING AN ELECTRODE WHICH TAKES THE PLACE OF A TOOL; SUCH WORKING COMBINED WITH OTHER FORMS OF WORKING OF METAL
  • B23H5/00—Combined machining
  • B23H5/04—Electrical discharge machining combined with mechanical working
• • 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
  • B24B1/00—Processes of grinding or polishing; Use of auxiliary equipment in connection with such processes
  • B24B1/002—Processes of grinding or polishing; Use of auxiliary equipment in connection with such processes using electric current
• • 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
  • B24B19/00—Single-purpose machines or devices for particular grinding operations not covered by any other main group
  • B24B19/02—Single-purpose machines or devices for particular grinding operations not covered by any other main group for grinding grooves, e.g. on shafts, in casings, in tubes, homokinetic joint elements
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23H—WORKING OF METAL BY THE ACTION OF A HIGH CONCENTRATION OF ELECTRIC CURRENT ON A WORKPIECE USING AN ELECTRODE WHICH TAKES THE PLACE OF A TOOL; SUCH WORKING COMBINED WITH OTHER FORMS OF WORKING OF METAL
  • B23H2600/00—Machining conditions
  • B23H2600/10—Switching of machining conditions during machining
  • B23H2600/12—Switching from rough cutting to finish machining

Definitions

• the invention relates to a method and a combined grinding and EDM machine for machining a workpiece.
• the workpiece is in particular ⁇ sondere to a product to be nachzubeindes or tool such as a drill, a milling cutter with or without inserts, a reamer, etc.
• Such a method is known for example from DE 37 17 568 AI.
• a method for the mechanical grinding of workpieces by means of electrically conductive grinding tools is proposed.
• a workpiece is first machined by a first tool by Funkenerosi ⁇ on or erodierschleifend. Subsequently, a tool change takes place.
• the workpiece is finished machining ⁇ tet in the same clamping means of a grinding tool.
• the dressing has a plurality of electrodes in order to edit the grinding surface of the grinding ⁇ zeugs with one of the electrodes by spark erosion.
• the individual electrodes are from each other
• the method and the grinding and Erodiermaschi ⁇ ne are set up for machining a workpiece.
• the workpiece is in particular a tool to be machined, for example a drill, a
• the workpiece consists at least partially of hard or super hard materials, such as polycrystalline diamond (PCD) or cubic crystalline boron nitride (CBN).
• PCD polycrystalline diamond
• CBN cubic crystalline boron nitride
• the combined grinding and EDM tool may have a corresponding contour on its outer circumference.
• the outer ⁇ dimension of the grinding and EDM tool after Ero ⁇ dieren and before grinding is substantially unchanged, so that even with a machining of the workpiece under ei ⁇ nem angle (inclination of the tool longitudinal axis relative to the axis of rotation of the grinding and Erodierwerkmaschines) kei ⁇ ne so-called profile distortion.
• the diameter of the eroding disc is changed relative to the grinding wheel during workpiece machining, other relative alignments or regression lativpositionen between the tool and the workpiece are set, as in eroding, for example, when editing a helix (eg a twist drill as a workpiece).
• deviations may occur and the accuracy of workpiece machining decreases.
• Such a profile distortion of the profile to be produced on the tool is inventively avoided by the same grinding and eroding tool is used both for eroding, as well as for subsequent grinding. Based on the operating parameters during erosion (voltage, current, etc.), the position and dimension of both the workpiece and the grinding and EDM tool are very accurately known before grinding. The grinding process is not only gentle, with low material removal , son ⁇ countries also with high precision.
• the circumferential profile of the combined grinding and EDM tool can be arbitrary.
• a radius of less than 1 mm and, for example, a radius of 0.5 mm may be present on the outer circumference.
• the radius can connect two surface sections, between which an angle of max. 60 degrees is included.
• the grinding can be performed by contour-parallel grinding, by piercing and / or a combination thereof.
• the grinding and EDM tool is dressed after eroding and before grinding the workpiece by means of a dressing tool.
• the dressing can be used to reduce or eliminate geometric deviations of the outer contour of the grinding and eroding tool which have arisen during erosion. to increase the precision of the grinding.
• the dimension and / or contour geometry of the grinding and eroding tool is set with high accuracy in the same clamping of the grinding and eroding tool and is precisely specified and known for subsequent grinding.
• the dressing tool can be as example ⁇ be an erosion tool.
• the dressing is therefore preferably carried out by spark erosion.
• the grinding and EDM may comprise eroding aufwei ⁇ sen, which can reverse the polarity so that optionally the abrasive ⁇ and erosion tool for spark erosion of the workpiece or the dressing tool to spark erosion in the grinding and erosion ⁇ tool can be used.
• Such a dressing with ⁇ means of spark erosion is very gentle and can be so out ⁇ results in the outside diameter of the grinding and Erodierwerkmaschineschws is only reduced to the extent as it is erfor ⁇ sary.
• the EDM and grinding the workpiece he ⁇ follows, in particular in the same setting of the grinding ⁇ and Erodierwerkmaschines.
• the dressing of the grinding and Ero ⁇ dierwerkmaschines is preferably carried out in the same clamping, as the erosion and grinding of the workpiece. Also by this measure, the accuracy when grinding the workpiece can be increased.
• the workpiece is preferably processed in a single clamping.
• the grinding of the workpiece can be done in one or more passes. If several
• the grinding of the workpiece can also be done by a pendulum grinding, in which the tool is moved relative to the workpiece transversely to a feed direction pendulum. By commuting, the wear of the
• the outer dimension of the grinding and EDM tool can be determined before and / or during the grinding of the workpiece.
• a measuring device may be present.
• the measuring device can determine the outer dimension by different methods, for example touching or non-contact with a Tastein ⁇ direction, electrically by evaluation of a voltage and / or current between the grinding and eroding tool and the workpiece and / or visually, etc. Also any combination The above method can be used.
• the outer dimension of the grinding and EDM tool changes or deviates from a desired dimension, such a deviation can be compensated by adjusting the delivery control technology. For example, during grinding of the workpiece, depending on electrical measured variables, it is possible to record on the grinding and eroding tool and / or on the workpiece and to use it to determine the outside dimension. This allows compensation by adjusting the position and / or orientation of the grinding and eroding tool relative to the workpiece during grinding.
• the workpiece Before machining with the combined grinding and eroding tool, the workpiece can, so to speak, in one Preprocessing be pre-processed by another machining tool in one (eg roughing). In the further machining tool, it may be an erosion tool so that is removed in Vorbearbei ⁇ processing methods by eroding material from the workpiece.
• an erosion machining of the workpiece can additionally be performed in supportive manner. This will be between the
• the electrical relatively low-resistance connection between the grinding and eroding tool and the workpiece must be interrupted during grinding. If the grinding, for example, repeated feeding and removal of the grinding and EDM tool from the work ⁇ piece is performed, forms a spark gap to allow erosion.
• the grinding and erosion tool can as Example ⁇ also distributed on the periphery arranged not have electrically conductive areas. If such a region comes into contact with the workpiece, the electrical connection between the workpiece abutting grinding and EDM tool and the workpiece is interrupted, so that a flashover can erode to form.
• the polarity of the erosion voltage is preferably switchable. As already explained, this can be done a material erosion grinding and erosion tool in ⁇ play as during dressing. The switching over of the Po ⁇ ment can also be done during the machining of the workpiece, for example, to resharpen the tool. Since ⁇ at the workpiece is then used as a kind of Erodierelektro ⁇ de.
• the grinding and EDM tool has in the Ausry ⁇ tion example an electrically conductive matrix, in the
• the abrasive ⁇ particles are made of a hard or super hard material, such as diamond, polycrystalline diamond (PCD), Edelkorrund, silicon carbide, cubic crystalline boron nitride
• An abrasive according to the invention and Erodiermaschi ⁇ ne has a control device. The combined
• the control means is adapted to carry out the method explained before ⁇ standing and control.
• FIG. 1 is a schematic block diagram similar representation of a grinding and EDM machine according to an embodiment
• Figure 2 is a schematic representation of an off ⁇ guidance example of a combined grinding and erosion ⁇ tool in a side view taken along an axis of rotation during erosion of the workpiece
• Figure 3 is a schematic representation of the
• FIG. 4 shows the grinding and eroding tool from FIGS. 2 and 3 in a side view along the axis of rotation during grinding of the workpiece;
• Figure 5 is a schematic representation of a wei ⁇ cal embodiment of a grinding and eroding ⁇ zeugs in a side view along the axis of rotation and
• Figure 6 is a flowchart of an exemplary embodiment of a method according to the invention.
• FIG. 1 shows a grinding and eroding machine
• the grinding and EDM machine 10 includes an axle assembly 11 which includes at least one preference and ⁇ , a plurality of translational and / or rotational Maschi ⁇ nenachsen.
• About the axle assembly 11 is at least one combined grinding and eroding tool 12 and optionally at least one further machining tool 13 is moved relative to a workpiece 14 and aligned.
• the workpiece 14 is clamped in a workpiece clamping device 15.
• the at least one tool 12, 13 and / or the Maschinentschspan ⁇ n driving 15 are moved via the axle assembly 11. Which of the machine axes is used for the movement of the at least one tool 12, 13 and / or for the movement of the workpiece clamping device 15 depends on the consequent creten versions of the grinding and EDM machine 10 and may vary.
• the axle assembly 11 has, for example, up to six machine axes and according to the example up to three tanslatorische machine axes x, y, z and up to three rotary machine axes rx, ry, rz.
• the grinding and erosion tool 12 and we ⁇ ilias a further machining tool 13 are arranged at ⁇ play according to a common machine spindle 16 ⁇ which is translationally by means of the axle assembly 11 and / or rotationally movable and positionable.
• the tools 12, 13 are driven about a rotation axis D. If a grinding takes place with a tool 12, 13, the relevant tool 12, 13 is driven about the axis of rotation D. When eroding with a tool 12, 13 it can be driven to rotate about the rotation axis D or stand still.
• the grinding and eroding machine 10 has a control device 20.
• the control device 20 controls the axle assembly 11. It also controls a motor, not shown, of the machine spindle 16 in order to drive the tools 12, 13, if necessary rotating.
• the control device 20 is also communicatively connected to an operator interface 21, via which an operator can make inputs and transmit them to the control device 20.
• the control device 20 can output information to the operator via the operator interface 21.
• the operator interface 21 may comprise any input and / or output means such as a touch-sensitive screen ⁇ be.
• the grinding and EDM has also ei ⁇ nen eroding 22.
• the erosion generator generates a Erodiercontent between a designed as erosion tool led tool 12, 13 and the workpiece 14.
• Flashover can be removed material on the workpiece 14.
• the grinding and EDM machine 10 has except ⁇ a dressing tool 23, which is formed in theforementionedsbei ⁇ game by an erosion electrode 24. Via the erosion generator 22, an erosion voltage can be applied between the erosion electrode 24 and a tool 12, 13 of the grinding and eroding machine 10 in order to remove material from the relevant tool 12, 13.
• the relevant tool 12, 13 can be dressed in this way and adapted to ei ⁇ ne predetermined desired geometry.
• the eroding voltage can be reversed by the erosion generator 22.
• the controller 20 may drive the erosion generator 22 to apply the desired erosion voltage and the desired polarity of the erosion voltage.
• the control device 20 can control the erosion generator 22 or an additional current and / or voltage source independent of the erosion generator 22 in order to apply a voltage or to generate a current flow for measuring purposes between the tool 12, 13 and the workpiece 14.
• a dimension of the workpiece 14 before and / or during processing can be determined on the basis of the current relative position between the tool 12, 13 and the workpiece 14. This can be done for example by applying ei ⁇ ner measurement voltage between the grinding and eroding tool, wherein in a contact, a current flows, the ge can be measured. Also, by evaluating at least one electrical quantity during erosion, the position and thus the geometry of the workpiece 14 can be determined.
• the grinding and eroding machine 10 may have a measuring device 25 in the embodiment, which may have a corresponding electrical measuring means 26 for measuring a voltage and / or a current.
• the electrical measurement means 26 may be arranged stationary with respect to the Ma ⁇ schin base and optionally part of the STEU ⁇ er adopted 20 and / or the Erodiergenerators 22nd
• the measuring device 25 may also include other measuring means, such as a tactile measuring means 27 and / or an optical measuring means 28.
• the outer dimension of the grinding and eroding tool 12 can be determined exactly. This can be done before and / or during machining of the workpiece 14. Changes in the outer dimension can be compensated by the control device 20.
• the measuring device 25 and the control device 20 are connected by communication. Depending on the type of execution of the measuring device 25, it may be movable and / or alignable via the axle arrangement 11, for example if it has a tactile measuring means 27 and / or an optical measuring means 28.
• FIGS. 2 to 4 schematically an embodiment of a grinding and Erodierwerkmaschines veran illustrates ⁇ .
• the grinding and EDM tool has an electrically conductive matrix 31, are incorporated in the abrasive particles 32 ( Figure 2).
• the matrix 31 with the abrasive particles 32 incorporated therein is shown diagrammatically in FIGS.
• the electrically conductive matrix 31 symbolized by a cross-hatching.
• the abrasive particles 32 can be made (PCD), cubic boron nitride (CBN), fused alumina, silicon carbide or a ⁇ of the or super hard material from Dia ⁇ mant, polycrystalline diamond.
• the workpiece 14 to be machined is also, by way of example, a tool that is entirely or partially made of a hard or superhard material that may correspond to one of the materials that make up the abrasive particles 32.
• the tool may be a drill, a router with or inserts, a reamer, etc.
• the grinding and eroding tool 12 tapers - according to the example symmetrical to a radial center plane - radially to the rotation axis D to the outside, at least in a peripheral region.
• it may have a radius R, which is preferably smaller than 1.0 mm and more preferably at most 0.5 mm.
• This peripheral region of the grinding and Erodierwerk ⁇ zeugs 12 can also be configured differently depending on the application. It is possible to use ⁇ small radii R and betragsmä ⁇ SSIG small angle so that workpieces 14 with very intricate geometries, such as twist drills or milling tools of small diameter with small konve ⁇ complexes and / or concave portions edit very accurate.
• FIG 6 illustrates a preferred embodiment of a driving Ver ⁇ below, the run with the above ⁇ be written grinding and EDM machine 10 who can ⁇ .
• the method is started in block S.
• An ⁇ closing a Vorbearbeitungsbacter is carried out with the out as erosion tool ⁇ led machining tool 13 in a first process step VI.
• the workpiece 14 is processed material removal with a relatively large material removal rate, so to speak in one
• the workpiece 14 can be machined in one or more passes by erosion or spark erosion.
• the control device applies an erosion voltage between the erosion tool 13 and the workpiece 14 via the erosion generator 22.
• the eroding tool 13 and the workpiece 14 are moved relative to each other, so that one of the actual contour to be produced on the workpiece 14 remains approximately contoured with a first allowance.
• the erosion tool 13 can be dressed by means of the dressing tool 23 after one or more passes of the erosion processing.
• the outer dimension, and the geometry of the Ero ⁇ commanding tool 13 via the measuring device 25 can be determined who carried ⁇ and a corresponding dressing.
• the dressing of the electrode 24 may be used, wherein the eroding 22 abuts a correspondingly umpoled Erodierposition between the erosion electrode 24 and the erosion tool 13 so that material is removed mainly at the Ero ⁇ commanding tool. 13
• another dressing tool such as a rotary chisel to be used.
• the tool is changed in a second method step V2, with which the workpiece 14 is further processed in the same clamping.
• the subsequent processing preferably only the combined grinding and EDM tool 12 is used.
• a third method step V3 is the
• the grinding and eroding tool 12 can be driven around the rotation axis D ⁇ or alternatively stand still.
• the erosion in the third process step V3 may analogously to Vorbearbei ⁇ processing methods carried out in one or more passes. Between several passes during erosion machining of the workpiece 14 or after completion of the erosion in the third method step V3, the grinding and EDM tool 12 can be measured by means of the measuring device 25 in an optional fourth method step and dressed in the presence of a devia ⁇ tion of a desired contour by means of the dressing tool 23 become.
• the dressing is carried out in the embodiment described here, using the erosion electrode 24 wherein the erosion generator 22 applies a corresponding Erodier phenomena between the erosion electrode 24 and the grinding and Ero ⁇ commanding tool 12 such so that mainly Mate ⁇ rial is removed from the grinding and erosion tool 12th Dressing is performed with minimal material removal ⁇ .
• the second allowance is removed in the fifth method ⁇ step V5 by grinding to bring the actual size with the nominal size in accordance. Since the same grinding and eroding tool 12 is used in the same setting for the EDM processing and the grinding in the method steps V3 and V5, the second oversize outer contour of the workpiece 14 and its position relative to the grinding and eroding tool 12 after the third method step V3 very well known, for example, with a maximum tolerance of 2 ⁇ . This makes it possible to remove only a small amount of material when grinding the workpiece 14. In other words, the second allowance is very small. This leads to the fact that with fibrous geometries, eg very small radii R, of the
• Grinding and eroding tool 12 can be worked without the wear of the grinding and eroding tool 12 is too large. It can be very filigree areas with small convex or concave radii, undercuts or the like on the workpiece 14 edit.
• the grinding in the fifth method step V5 can be contour-parallel and / or by piercing.
• the second allowance remaining after the erosion machining in the third method step V3 can be measured in a grinding pass. or in several consecutive grinding passes.
• the grinding and erosion tool 12 comprises an electrically conducting matrix 31, via the STEU ⁇ er owned 20 and nungs- an appropriately controlled voltage or current source, a voltage between the workpiece 14 and the grinding and erosion tool 12 are applied.
• a voltage between the workpiece 14 and the grinding and erosion tool 12 are applied.
• the desired material removal can be compensated for by a corresponding readjustment of the relative position or relative orientation between the grinding and eroding tool 12 and the workpiece 14 by driving the axle assembly 11. It is also possible during the
• the grinding process in the fifth method step V5 can be supported in a modified embodiment of the method by spark erosion.
• FIG. 5 a modified embodiment of the grinding ⁇ and erosion tool 12 is used, which is schematically illustrated in FIG. 5
• the grinding and EDM tool is divided into circular arc-shaped processing sections, in which the electrically conductive matrix 31 is present with the abrasive particles 32 embedded therein.
• the processing sections 35 are electrically isolated from each other.
• a electrically non-conductive region 36 available between each two immediately adjacent processing sections 35 .
• dimen ⁇ solution of the electrically non-conductive region 36 Minim ⁇ least as large as the contact area between the abrasive ⁇ and erosion tool 12 and the workpiece 14 in the
• At least one of the following measures can also be taken to assist the grinding:
• the erosion generator 22 can generate a pulsed current profile
• the grinding and eroding tool 12 can be repeatedly moved away from the workpiece 14 and toward the workpiece 14 to allow sparking;
• the erosion generator 22 can generate a constant or variable regulated current, preferably direct current, which assists in electrochemical (anodic / cathodic) grinding without sparking.
• step V5 corresponds the actual size of the workpiece 14 - within the specified accuracy - the nominal size and the method is solveschlos ⁇ sen (end E).
• the invention relates to a method and a grinding and EDM machine 10 for processing a work ⁇ piece 14.
• a combined grinding and Ero ⁇ dierwerkmaschine 12 is used, in the same clamping for eroding the workpiece 14 and a subsequent grinding of the workpiece 14 is used.
• the allowance at each point is about 2 to 3 ⁇ .
• the fact that the same grinding and EDM tool 12 is used in the same setting for Ero ⁇ dieren and grinding, the subsequent grinding can be done with a very low Materialab ⁇ contribution . It can therefore very delicate memoriskontu- ren the grinding and Erodierwerkmaschines used and generated the corresponding ⁇ very delicate and complex geometries on the workpiece fourteenth

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Grinding-Machine Dressing And Accessory Apparatuses (AREA)
• Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
• Grinding And Polishing Of Tertiary Curved Surfaces And Surfaces With Complex Shapes (AREA)
• Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)
• Constituent Portions Of Griding Lathes, Driving, Sensing And Control (AREA)

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Applications Claiming Priority (2)

Publications (1)

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Cited By (1)

Citations (8)

Family Cites Families (5)

• 2017
  • 2017-05-11 DE DE102017110196.9A patent/DE102017110196B4/de active Active
• 2018
  • 2018-05-04 WO PCT/EP2018/061577 patent/WO2018206454A1/de active Application Filing
  • 2018-05-04 CN CN201880030868.2A patent/CN110573301A/zh active Pending
  • 2018-05-04 JP JP2019561170A patent/JP2020519462A/ja active Pending
  • 2018-05-09 TW TW107115677A patent/TW201906677A/zh unknown

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