EP1312446B1 - Diamond form dressing roller and manufacturing method - Google Patents

Abstract

The roller (10) to dress diamond grinding disks, in a ceramic or metal or synthetic resin bonding, has a metal carrier body (12). It has a cladding (14) in at least one layer, and the separate diamond fragments are of sizes within very tight tolerances, arranged on a plane at right angles to the rotary axis of the roller. The diamonds are laid out in a pattern so that, as the grinding disk wears, the grinding action remains constant. The diamonds are laid in their patterns with an adhesive layer, on a ring-shaped underlay which can be melted away. The bonding powder is added, and the material is compressed while cold, to be sintered. The shaped ring cladding is ground around the circumference.

Description

The invention relates to a diamond Formabrichtrolle for dressing diamond grinding wheels in ceramic, bakelitischer or metallic bond according to the preamble of claim 1. An example of such a diamond form dressing roller is from the JP 04 343674 A known.

For grinding profiles in workpiece surfaces grinding wheels are used, which have geometrically defined profiles on their grinding surface. These profiles must first be incorporated by dressing in a new disc and then reworked from time to time because of the occurring during grinding grinding wheel wear. Abrasive wheel wear can result in both impermissible profile deviations and inadequate grinding behavior, whereby the grinding forces, the temperature of the workpiece surface and / or the surface roughness get out of tolerance.

The dressing of a profile grinding wheel is often done either with a profile dressing roller or a diamond form dressing roller. A profile dressing roller has the workpiece contour on its peripheral surface. This is in contrast to a diamond form dressing roll, which is controlled with a CNC control of the grinding machine according to the required profile. For CNC controlled dressing of conventional Grinding wheels with abrasives made of corundum or silicon carbide have proven themselves to diamond form dressing rollers, which carry a layer of diamonds on their circumference. This diamond layer may consist of a diamond grain in a bond of electrodeposited nickel or of polycrystalline diamond aggregates, which are held on the surface of the Formabrichtrolle by a galvanically or chemically deposited nickel precipitate or by a sintered metal deposited in a sintering process.

Partly very small concave radii must be introduced into the grinding wheel surface in order to realize very small corner radii on the workpiece, e.g. 0.2 or 0.1 mm. For this purpose, form dressing rollers are ground in their largest diameter, so that a convex radius is formed with a corresponding diameter. The resulting from the dressing of these fine edges wear on the Formabrichtrolle is naturally high. If the wear exceeds the profile tolerance, the form dressing roller must be reground or replaced.

When dressing cubic crystalline boron nitride grinding wheels, the wear on a diamond form dressing roll is so great that the economics of the entire grinding process with CBN grinding wheels is in question. Out EP 0 116 668 B1 a Formabrichtrolle has become known which solves this problem by a perpendicular to the axis of rotation of the dressing roller multi-layer diamond coating and in the direction of the axis of rotation einschichtigen diamond coating. The diamond coating forms perpendicular to the axis of rotation of a profile that self-generated at constant dressing conditions and thus allows a larger amount of wear without the profile gets out of tolerance. With the known Formabrichtrolle fine profiles can be realized by the choice of a finer grain size.

Dressing consists of profiling and sharpening the grinding wheel. The profiling is required to return the profile of the grinding wheel to the desired shape and tolerance. The sharpening takes place to further restore the grinding ability of the grinding wheel, i. to bring the grinding forces, the heat development and the surface roughness created on the workpiece back into the required limits.

In conventional grinding wheels, both requirements can be accomplished by a single process. For CBN grinding wheels, the profiling and sharpening had to be carried out successively, because the lower hardness difference between diamond and CBN in conventional profiling produces an abrasive coating with insufficient grinding properties, which is characterized by too little excess over the bonding level and thus too small chip space. Only after the so-called touch-dressing process was developed, dressing deliveries could be realized, which are only a few micrometers and in which the dressing process does not destroy the grain supernatant on the bond.

Out Patent Abstracts of Japan Vol. 017, No. (M-1398), April 19, 1993 and JP 04 343674 A (TOYDA MACH WORKS LTD.) A dressing tool has been known in which, to obtain a uniform distribution and constant density of abrasive grains of an annular body in its planar surface, holes are drilled according to a predetermined pattern of the same dimensions in which ultra-hard abrasive grains are arranged. Two or more layers of such metal bodies are sintered and cured, the layers being metallically bonded together.

The invention has for its object to provide a Formabrichtrolle, with the profiling and sharpening of diamond grinding wheels in a single gear possible and the wear of Formabrichtrolle is so low that even long profile trains can be dressed on a diamond grinding wheel with high profile accuracy.

This object is solved by the features of patent claim 1.

In the form dressing roll according to the invention, the coating also has at least two layers of diamond grains of narrow size. In each layer, the diamond grains are arranged approximately in a plane perpendicular to the axis of rotation of the dressing roll according to a predetermined setting scheme. In the setting scheme, which will be discussed in more detail below, the diamond grains are arranged at intervals from each other. The adjacent layers are arranged so that the diamond grains of one layer are disposed in gaps of the diamond grains of the other layer and partially protrude into the other layer. The layers are thus interlocked or entangled, so that the thickness of the abrasive coating viewed in the axial direction is less than the sum of the grain diameters. When referring to layers, it is not intended to indicate that separate layers must be made from the outset, each with a plane of diamond grains perpendicular to the axis of rotation, although this is a convenient method of manufacture; rather, it should primarily be the geometric structure of the lining dargetan. The set pattern after the individual diamond grains of narrow classified size are set is such that the peripheral geometry of the form dressing roll remains approximately constant in wear progress.

With the form dressing roller according to the invention results in a broader diamond coating than in the above known Formabrichtrolle, the grain sizes are chosen so that at the edges of the pads natural radii arise that generate themselves and correspond to the smallest predetermined concave radius on the grinding wheel.

The width of a coating of two layers according to one embodiment of the invention is e.g. one and a half times the grain size. For four layers this gives a width of three grain sizes.

Various setting schemes are conceivable in order to realize the teaching of claim 1. One according to an embodiment of the invention provides that the setting scheme has at least one spiral or a plurality of geometrically identical spirals with a common center whose maximum diameters are circumferentially offset by an equal angle and along which the diamond grains are set, the center on the axis of rotation the Formabrichtrolle lies. If two layers are produced according to this setting scheme and then assembled, a corresponding angular rotation of the layers relative to one another is required in order to ensure the mentioned entanglement of the diamond grain arrangements.

In another embodiment of the invention, the diamond form dressing roll consists of dressing platens arranged radially on their circumference, which are connected to one another via a metallic bond which is easy to sand. For this example, sintered cobalt can be used.

In the individual, e.g. rectangular platelets are again provided with at least two layers of diamond grit arrangements, each layer having a predetermined set pattern, and the diamond grains of adjacent layers are disposed in gaps of diamond grains of the other layer and the layers partially interengaging to achieve the goal of a wear-independent recirculating geometry , Again, since the edge radii of the forming roller are formed only by defined diamonds at defined locations, it is also possible to machine defined radii hereby.

As a binding for a form dressing roll according to the invention, it is preferable to use a high tungsten content galvanic or sintered bond. The grain size is equal to or smaller than 1.5 mm, and the length of the abrasive coating in the feed direction is preferably between 5 and 10 mm.

• Setzen der Diamantkörner nach dem vorgegebenen Setzschema auf eine Unterlage, mit Klebschicht für Herstellung einer Schicht,
• Zugabe von Bindungspulver,
• Stapeln der gewünschten Anzahl von Schichten unter Relativ- bzw. Winkelverschiebung der Schichten zu einem Paket
• Kaltverdichten des Schichtenpakets,
• Sintern

Various methods are conceivable for producing a form dressing roller according to the invention. A method according to the invention provides the following steps:

• Setting the diamond grains according to the predetermined setting scheme on a substrate, with adhesive layer for producing a layer,
• Addition of binding powder,
• Stacking the desired number of layers with relative or angular displacement of the layers into a package
• Cold compacting the layer package,
• sintering

For multiple layers, these are prepared separately and stacked, possibly under relative displacement or rotation, after which the stack is cold-densified. Subsequently, if necessary, a grinding or finishing of the Formabrichtrolle thus produced.

Fig. 1

zeigt die Seitenansicht einer Formabrichtrolle nach der Erfindung in schematischer Darstellung.

Fig. 2

zeigt eine Ausschnittsvergrößerung der Formabrichtrolle nach Fig. 1.

Fig. 3

zeigt schematisch einen Teil eines Radialschnitts durch die Formabrichtrolle nach Fig. 1.

Fig. 4

zeigt die Draufsicht auf ein Teil der Formabrichtrolle nach Fig. 3.

Fig. 5

zeigt schematisch ein Setzschema für Diamantkörner einer Schicht einer Formabrichtrolle nach den Figuren 1 bis 4.

Fig. 6

zeigt das Setzschema einer Formabrichtrolle mit zwei Schichten gemäß Fig. 5.

Fig. 7

zeigt schematisch eine andere Ausführungsform einer Abrichtrolle nach der Erfindung.

Fig. 8

zeigt in Draufsicht eine erste Schicht eines Plättchens der Abrichtrolle nach Fig. 7.

Fig. 9

zeigt die Seitenansicht der Schichten nach Fig. 8.

Fig. 10

zeigt die Draufsicht auf eine zweite Schicht des Plättchens der Formabrichtrolle nach Fig. 7.

Fig. 11:

zeigt die Seitenansicht eines aus den Schichten nach Fig. 8 und 10 zusammengesetzten Plättchens für die Formabrichtrolle nach Fig. 7.

The invention will be explained in more detail with reference to drawings.

Fig. 1

shows the side view of a Formabrichtrolle according to the invention in a schematic representation.

Fig. 2

shows an enlarged detail of the Formabrichtrolle after Fig. 1 ,

Fig. 3

schematically shows a part of a radial section through the Formabrichtrolle after Fig. 1 ,

Fig. 4

shows the top view of a part of the Formabrichtrolle after Fig. 3 ,

Fig. 5

schematically shows a setting scheme for diamond grains of a layer of a Formabrichtrolle after FIGS. 1 to 4 ,

Fig. 6

shows the setting diagram of a form dressing roll with two layers according to Fig. 5 ,

Fig. 7

schematically shows another embodiment of a dressing roll according to the invention.

Fig. 8

shows in plan view a first layer of a small plate of the dressing roll Fig. 7 ,

Fig. 9

shows the side view of the layers Fig. 8 ,

Fig. 10

shows the top view of a second layer of the plate of the Formabrichtrolle after Fig. 7 ,

Fig. 11:

shows the side view of one of the layers FIGS. 8 and 10 assembled platelet for the Formabrichtrolle after Fig. 7 ,

A form dressing roll for dressing diamond grinding wheels (not shown) in ceramic, metallic or synthetic resin bonding is shown at 10. The Formabrichtrolle has a support body 12, for example made of steel or the like, on which a coating 14 is applied. As in particular from Fig. 2 To recognize the covering consists of individual Diamtkörnern 16, which have approximately the same size, for example 0.9 mm or less. As further out Fig. 2 can be seen, the diamond grains 16 are on rays 18, which go through a common center of the Formabrichtrolle 10. However, the diamond grains 16 are not all in one plane, but in two offset in the axial direction of the dressing roller 10 levels. The diamond grains 16 are arranged according to a predetermined setting scheme in two interlaced layers, wherein the diamonds of the one layer are arranged in gaps of the adjacent layers. This is a bit clearer 3 and 4 out. In Fig. 3 a lining 14a is indicated with the sides 20 and 21 and the peripheral surface 22. It can also be seen first diamond grains 24, which are characterized by circular lines and second diamond grains 26, which are additionally hatched. The hatching should only indicate that the diamond grains 24 and 26 are not in the same plane, which is in Fig. 3 in the circumferential direction and in Fig. 4 meant in the radial direction. Like from the FIGS. 3 and 4 recognizable form the diamonds 24, 26 each in the radial direction a layer or a plane, wherein the diamonds of one layer are offset from the diamonds of the other layer, but interlocked with each other. The corresponding setting scheme, according to which the diamonds 24, 26 can be arranged, results as an example in FIG Fig. 5 ,

In Fig. 5 six geometrically identical spirals 30 are arranged inside each other, wherein the largest diameter is offset by 30 °. The spirals 30 are each drawn at an angle of about 360 °. Starting with the largest diameter, in each case six diamond grains 32 are arranged at a distance of 30 °. On the marked rays, which are arranged at a distance of 15 °, therefore alternately radially three or two diamonds 32 can be seen. The diamonds 32 are incorporated into a matrix which consists of a suitable binder, for example a galvanic or a sintered bond with a high tungsten content. The binder is in 3 and 4 denoted by 34. Become two layers according to Fig. 5 set against each other with a certain angular rotation, resulting in a scheme according to Fig. 6 , In Fig. 6 For example, the diamond grains 32 are again arranged on the rays offset by 15 °, wherein the diamond grains 36, which are additionally marked with a dot, are arranged in each case centrally between the rays. However, the diamond grains 36 belong to a plane offset in the axial direction, the offset being smaller than the size of a diamond. An example of the size of an offset is in the 3 and 4 shown. The offset is, for example, such that the thickness of the overall coating, eg 14a according to 3 and 4 is about 1.5 times the diameter of the diamond grains 24, 26 and 32, 36, respectively. Thus, on the outermost diameter of the dressing form roll, twelve diamonds are centered around the common center of the spirals 30, which is also the fulcrum of the forming roll. As wear progresses, diamonds come second on the spiral, and so on. Thus, even with progressive wear an approximately constant Umflächengeometrie the Form dressing roll, which generates itself in the course of their life. This also applies in particular to the edges 40, 42 of the covering ( 3 and 4 ). The edge radii remain constant over the wear cross section. Thus, the profile radii remain constant on the workpiece to be dressed. Since the dressing volume of the Formabrichtrolle is relatively large, the geometric wear in the direction of delivery is relatively small, so that even larger profile trains can be trained with great profile accuracy.

It is also possible, for example, the diamonds 32 after Fig. 5 to arrange on a single spiral 30 in order to achieve the uniform wear in the radial direction. With several spirals rotated relative to each other, the diamond grains may be arranged approximately in a plane to obtain the minimum width of the coating from the diameter of a grain. During production, the diamond grains are placed on a fusible substrate and covered with sintered powder and finally sintered to obtain an annular coating.

In Fig. 7 is a Formabrichtrolle 50 shown schematically, which consists of a carrier body 52 and individual on the carrier body 52 radially arranged plate 54. In the present case, eight such plates 54 are provided. The platelets 54 are incorporated into a matrix 56 of a suitable readily-wearable binder 56 having, for example, sintered cobalt. The structure of the platelets 54 goes out of the FIGS. 8 to 11 out.

On a slide 58 in Fig. 8 columns and rows of diamond grains 60 are arranged. On a slide 62 after Fig. 10 Also, columns and rows of diamond grains 62 are arranged. Between adjacent diamond grains 60 and 62, respectively, there are sufficient gaps. Will now the arrangement after Fig. 8 from above on the arrangement Fig. 10 folded, results in an arrangement, such as they partly out Fig. 11 can be seen. Diamond grains 60 are respectively disposed between adjacent diamond grains 64 and gaps in the columns and rows of diamond grains 64, respectively, with diamond grains 60, 61 not being in a plane but being only partially interleaved, as shown Fig. 11 to recognize. It again results in a relatively similar arrangement, as based on the FIGS. 3 and 4 is indicated. The binding of the diamond grains 60 and 64 takes place on a galvanic basis or by a sintered metal.

Claims (12)

1. Form dressing roller comprising a coating made of diamond fragments in a suitable bond for dressing diamond grinding disks in a vitrified, metal or synthetic resin bond, in which the coating (14, 14a) consists of at least one layer, the coating (14, 14a) consisting of at least two layers and in each layer individual diamond fragments of closely graded sizes being arranged in one plane at right angles to the rotational axis of the form dressing roller (10, 50) according to a predetermined positioning pattern, characterised in that the diamond fragments of the one layer are located in gaps between the diamond fragments of the other layer and partially project into the other layer such that the circumferential surface geometry of the dressing roller (10, 50) remains approximately uniform as the wear continues.
2. Form dressing roller according to Claim 1, characterised in that a coating made of two layers has a width of approximately 1.5 times the fragment size.
3. Form dressing roller according to one of Claims 1 to 2, characterised in that the size of the diamond fragments is selected such that on the edges of the coating a predetermined radius is produced irrespective of the progress of the wear.
4. Form dressing roller according to one of Claims 1 to 3, characterised in that the positioning pattern has at least one spiral about the rotational axis of the form dressing roller on which the diamonds are positioned.
5. Form dressing roller according to Claim 4, characterised in that the positioning pattern has a plurality of spirals (30) which are geometrically the same and with a common central point, the largest diameters thereof being spaced apart by the same angular distance in the peripheral direction and along which diamond fragments (32) are positioned, the central point being located on the rotational axis of the form dressing roller.
6. Form dressing roller according to one of Claims 1 to 5, characterised in that it consists of separate, preferably rectangular or trapezoidal thin sheets (54), which are arranged in succession in the peripheral direction of the form dressing roller, each thin sheet comprising at least two layers which are arranged in one plane at right angles to the rotational axis of the dressing roller.
7. Form dressing roller according to Claim 6, characterised in that the thin sheets (54) are held in a metal matrix (56) made of material which may be easily abraded.
8. Form dressing roller according to Claim 7, characterised in that the material consists of sintered cobalt.
9. Form dressing roller according to one of Claims 1 to 6, characterised in that an electroplated or a sintered bond is provided with a high proportion of tungsten to the diamond fragments.
10. Form dressing roller according to one of Claims 1 to 9, characterised in that the size of fragments is the same as, or smaller than, 0.3 mm.
11. Form dressing roller according to one of Claims 1 to 10, characterised in that the length of the abrasive coating in the feed direction is 5 to 10 mm.
12. Method for producing a form dressing roller according to Claim 1, characterised by the following steps:

    - placing the diamond fragments according to the predetermined positioning pattern on a base layer with an adhesive layer for producing a layer,

    - addition of bonding powder,

    - building-up the desired number of layers by the relative and/or angular displacement of the layers to form a set of layers,

    - cold compaction of the set of layers,

    - sintering.

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