WO2018130237A1

WO2018130237A1 - Roughing disk with a core comprising at least one grinding additive

Info

Publication number: WO2018130237A1
Application number: PCT/DE2017/100692
Authority: WO
Inventors: Markus Moos; Bernd Conradi; DR. Thomas KAMPS
Original assignee: Klingspor Ag
Priority date: 2017-01-16
Filing date: 2017-08-17
Publication date: 2018-07-19

Abstract

The invention relates to a roughing disk for machining material surfaces, comprising a disk-shaped main body which comprises a central opening, through which an axis of rotation passes, for the direct or indirect connection of a driveshaft of a tool, at least one grinding layer which comprises a first material mixture including at least one first grinding additive, and a stabilizing core for stabilizing the roughing disk, said stabilizing core being associated with the at least one grinding layer and being disposed peripherally adjacent to the central opening. The stabilizing core comprises a second material mixture, which comprises at least one second grinding additive different from the first grinding additive.

Description

Grinding disc comprising at least one abrasive additive

core

The invention relates to a roughing disc having the features of the preamble of patent claim 1.

Such a roughing disc is known in practice and is suitable for the rough grinding of material surfaces of various materials. It comprises a disk-shaped main body, which comprises a central recess for the direct or indirect connection of a drive shaft of a tool. The central recess is penetrated by a rotation axis. In addition, the base body comprises at least one abrasive layer. The at least one abrasive layer has a material mixture which comprises at least one first abrasive additive. A stabilizing core for stabilizing the roughing wheel is associated with the at least one grinding layer and arranged circumferentially adjacent to the central recess.

The previously known roughing wheel has no satisfactory grinding performance, especially at high speeds. The previously known stabilization core is free from abrasive additives, so that the stabilizing core at best nothing to

Grinding power contributes or can also reduce the grinding performance. The absence of abrasive additives in the stabilizer core reduces the abrasive active area between the roughing wheel and the material surface to be machined. The invention has for its object to provide a roughing disc of the aforementioned type, which is characterized by an improved grinding performance and also has improved stability. This object is achieved by the roughing disc with the features of claim 1.

The roughing disc according to the invention comprises a disk-shaped basic body which has a central recess, through which an axis of rotation passes, for the direct or indirect connection of a drive shaft of a tool and at least one

Comprises abrasive layer. The at least one abrasive layer has a first material mixture which comprises at least one first abrasive additive. A stabilizing core for stabilizing the roughing wheel is assigned to the at least one grinding layer and is disposed circumferentially adjoining the central recess. The roughing disc according to the invention is characterized in that the

Stabilizing core comprises a second material mixture, which comprises at least one different from the first abrasive additive second abrasive additive.

Compared to the known roughing disc, the use of a core within the roughing disc with a second abrasive additive can achieve further adaptation and improvement in stability as well as improved grinding performance. Namely, the core serves to stabilize the roughing disc during its rotation and the second abrasive additive increases the grinding performance by increasing the abrasive active area between the roughing disc and the material surface to be machined. The stabilizer core does not comprise a first abrasive additive.

To increase the abrasive surface while increasing the

Grinding performance is not enough to provide only the stabilizing core with the abrasive additive addition of the abrasive layer. The reason lies in the very different circumferential speeds of the grinding-active surface in the region of the grinding layer and the grinding-active surface in the region of the stabilizing core. The effect of a grinding additive on the grinding performance depends essentially on the peripheral speed. The roughing disc according to the invention takes account of this knowledge and therefore comprises abrasive active additives adapted to peripheral speeds of different regions of the roughing disc. Therefore, the first abrasive additive of the abrasive layer, which is designed for high rotational speeds, differs from the second abrasive additive of the stabilizer core, which is designed for lower rotational speeds. Thus, in the grinding process both areas of the abrasive surface can function optimally with the same number of revolutions of the roughing disc and ensure a high grinding performance.

Especially in the area of the central recess, where stresses resulting from the grinding process, such as rotational forces and side loads, are concentrated, the stabilizing core can optimize the stability of the roughing disc while improving grinding performance. Namely, during the grinding, the stabilizing core absorbs forces acting on the at least one grinding layer and transmits them uniformly over to the drive shaft of the tool. At the same time, the stabilizing core uniformly transmits the forces emanating from a user via the drive shaft of the tool to the at least one grinding layer. The stabilizing core thus also serves as a force transmission element between the at least one grinding layer and the connection to a drive shaft of a tool. The advantages of the roughing disc according to the invention are therefore in the concentration of mass in the region of its center of rotation, in the indirect power transmission between the at least one grinding layer and the drive shaft of the tool and in the improvement of the grinding performance. As a result, the roughing disc always remains stable even at high force or contact pressures and / or high speeds, easy to control and leads to a high grinding performance.

Assignment of the stabilizing ceramic to the at least one abrasive layer is to be understood as a spatial relationship. The stabilization core may be disposed in the same plane as and / or adjacent to the at least one abrasive layer.

In a preferred embodiment of the roughing wheel according to the invention, the second material mixture comprises, as a second abrasive additive, corundum, silicon carbide, zirconium corundum, solgel, ceramic and / or diamond. In a further preferred embodiment of the roughing wheel according to the invention, the second material mixture may comprise a mineral additive which is basalt, quartz sand, wollastonite, aluminum silicate and / or kaolin. Each of these additives has a strengthening effect on the bond. In addition, these additives increase the surface area between a binder, which may be resin and the grain. The constituents calcium, magnesium and silicate promote a bond between the functional resin group and the grain surface (usually OH groups). Kaolin also has ceramic properties due to the high alumina content and improves the modulus of elasticity. In a further preferred embodiment of the roughing disc according to the invention, the mineral additive may have a Mohs hardness of at least 2, preferably between 7 and 9. In particular, a high strength of the roughing disc can be ensured, the greater the hardness of the additive. The Mohs hardness describes the function of the mineral additive. Quartz sand and other silicates have a Mohs' hardness of 5 to 7 and can therefore have a very positive effect on the compressive strength. The Mohs hardness of kaolin is 2 to 2.5. In particular, in calcined form, this promotes the pressure stability.

In a further preferred embodiment of the roughing disc according to the invention, the mineral additive has a particle size of 30 to 1000 μm, preferably 200 to 500 μm. The grain size determines how well the pores are filled. The closer the core layer can be packed, the more bearing capacity can be generated and the higher the modulus of elasticity. The weak point of every bond is the bond distance. If the bond of two abrasive grains or minerals were rather large, then the resin would have to form the bridge. The thickness of this resin layer increases accordingly. Due to the brittleness of the resin on the one hand and the susceptibility of the resin bridge to moisture (so-called hydrolysis) on the other hand, it leads to microcracks, which in turn weaken the bond.

In a further preferred embodiment of the roughing disc according to the invention, the grain of the first abrasive additive and / or the grain of the second abrasive additive and / or the grain of the mineral additive with phenolic resin Systems comprising resol-novolak mixture, coated. Resoles are fusible, soluble phenolic resins that contain reactive methylol groups and are formed in the condensation of phenols with formaldehyde under basic conditions. The benzene rings are connected to each other via methylene groups and via ether bridges. Novolaks are phenolic resins with a formaldehyde-phenol ratio of less than 1: 1, which are obtained by acid condensation of the starting materials. This explains that the coating of the grain or mineral must fill the complete surface of the mineral very evenly and completely, so that the surface area of attack for the hydrolysis to be avoided is small and the binding forces between the surface groups of the minerals and the reactive groups of the resin are relatively large. The resol takes over the uniform distribution of the novolak on the mineral surface. Novolacs can form different network densities in three spatial directions. The degree of network density can be controllable. Also, the flowability of the novolak can be chosen differently, so that optimal wetting of the mineral surface is ensured, without the important for the scrubbing disc

Fill pore structure. On the other hand, it is important for the core filling that all pores are well filled to ensure the best possible modulus of elasticity.

In a further preferred embodiment of the roughing wheel according to the invention, the resol has a viscosity of 1000 to 5000 mPa s, preferably 1200 to 3500 mPa s. A low viscosity of the resole promotes fast and uniform wetting of all mineral substances. High viscosities tend to lead to thick layers of resin and penetrate only slowly into rugged surfaces of minerals.

In a further preferred embodiment of the roughing disc according to the invention, the novolak has a content of hexamethylenetetramine of at least 9% by volume, preferably 12 to 16% by volume and a flow distance of 15 to 35 mm, preferably 17 to 26 mm. The novolak can also be modified novolac. The hexamine content regulates the network density of the resin system to be achieved. A hexamine content of less than 9% by volume leads to rather low network density and to few bonding points between functional groups on the mineral surface and those of the resin. The higher the hexamine content, the more bonds can be formed. The flow route from 15 to 35 mm defines that optimum distribution of the novolak between the mineral surfaces is ensured without letting the pores of the abrasive layer taper, but sufficient to reinforce the pores of the core layer.

In a further preferred embodiment of the roughing wheel according to the invention, additional defined amounts of other additives and / or additives of less than 20% by volume may be added to the novolak. These additives of less than 20% by volume may be abrasive substances which react with a metal abrasive to prevent clogging of the pores of the abrasive layer by molten metal particles. In a further preferred embodiment of the roughing disc according to the invention, contact surfaces between two of the adjacent adjacent scrubbing disk elements reinforcing layer, abrasive layer and stabilizing core and / or between two adjacent abrasive layers have at least in sections a stochastic roughness profile. Conceivable adjacent scrubbing disk elements are thus reinforcing layer and abrasive layer, reinforcing layer and stabilizing core, abrasive layer and stabilizing core, abrasive layer and abrasive layer. An improvement of the bond between the individual grinding disk elements can be achieved by a mutual penetration of the individual grinding disk elements. That The elements do not have clear area boundaries (contact surfaces) to each other but penetrate each other or have a stochastic roughness profile in the contact surfaces to each other. By penetrating or the roughness profile results on the one hand an increase in the contact area for the chemical composite to the other results in a mechanical positive connection.

In a further preferred embodiment of the roughing disc according to the invention, a reinforcement fabric is arranged in at least one boundary region between two of the following adjacent roughing disk elements reinforcing layer, abrasive layer and stabilizing core and / or between two adjacent abrasive layers. Conceivable adjacent scrubbing disk elements for forming a boundary region are thus reinforcing layer and abrasive layer, reinforcing layer and stabilizing core, abrasive layer and stabilizing core, abrasive layer and

Abrasive layer. In addition to the stochastic expression of the contact surface can by the Use of reinforcing fabrics via a possible window and / or lattice structure of the fabric a targeted structuring of the contact surfaces can be achieved. It is quite desirable if the reinforcing fabric penetrates different depths into the individual layers. The reinforcing fabric may extend over the entire contact surface between two adjacent scrubbing elements. Alternatively, this reinforcing fabric may be both smaller than the outer diameter and larger than the inner diameter and / or extending over the individual layers. Depending on the abrasive grain, the mixture, the geometrical arrangement of the layers as well as the abrasive application, the reinforcement fabrics can be adapted in their extent between the layers.

In a further preferred embodiment of the roughing disc according to the invention, the stabilizing core has a cylindrical, conical, truncated, paraboloid or hyperboloidal shape. Due to the shape of the stabilizing core, the grinding performance of the roughing disc can be influenced over the duration of a grinding process. Since the roughing wheel is removed on its grinding side, if the stabilizing core has a changing cross section in the direction of the axis of rotation, for example, the surface portions of the grinding active surface in the region of the grinding layer change to the abrasive active surface in the region of the stabilizing core with respect to the total grinding surface. Thus, over the duration of a grinding process, the amount of first abrasive additive actively intervening in the grinding process changes with respect to the amount of second abrasive additive and vice versa.

The at least one abrasive layer can be mixed with various fillers and additives. The at least one abrasive layer can be used as the first abrasive additive abrasive grains, such as normal brown fused alumina and derivatives, blue aluminum alumina, white fused alumina, zirconia alumina, silicon carbide, ceramic grain ( ceramic grain), pink fused alumina, and / or monocrystalline alumina. In addition, the abrasive layers may include supporting fillers, such as polyaluminum fluoride, cryolite, pyrite, calcite, wollastonite, and / or graphite, which may be bonded with phenolic resin systems. Further advantages and advantageous embodiments of the subject matter of the invention are the description, the drawings and the claims removed.

An embodiment of a roughing disc according to the invention is shown schematically simplified in the drawing and will be explained in more detail in the following description.

The single FIGURE shows a section through a roughing disc according to the invention.

The roughing disc 1 shown in the drawing has a base body 3 with a layered structure. The main body 3 comprises a central recess 2, which is penetrated by a rotation axis 5 located in the center of rotation of the roughing disc 1. In the recess 2, an insert 4 for fixing the roughing disc I is arranged on a drive shaft of a tool. At the tool facing the tool side of the roughing disc, a reinforcing layer 6 is arranged. The reinforcing layer 6 may comprise rutile, wollastonite, calcite and / or basalt, which may be phenolic resin bonded. A grain size may be between 0.1 mm to 1.0 mm, preferably 0.2 mm and 0.5 mm. In addition, the reinforcing layer 6 may comprise quartz sand. Thus, the reinforcing layer 6 has high strength. It may comprise a net-like insert to further increase the stability of the roughing disc 1.

The roughing disc 1 also has two abrasive layers 8a, 8b, which are arranged on the side facing away from the tool side of the reinforcing layer 6. The abrasive layers have a first material mixture 14 which comprises at least one first abrasive additive 16. The first material mixture 14 and the first abrasive additive 16 are shown schematically in the figure and only a portion of the abrasive layer 8b, however, the first material mixture 14 and the abrasive additive 16 may be present in the entire abrasive layer 8a and / or abrasive layer 8b. The first abrasive additive 16 may be selected from the group comprising normal brown fused alumina and derivatives, blue aluminum alumina, white fused alumina, zirconia alumina, silicon carbide, Ceramic grain, pink fused alumina and / or monocrystalline alumina (monocrystalline alumina). n / A). In addition, the abrasive layers 8a, 8b may comprise supporting fillers, such as polyfluoride fluoride, cryolite, pyrite, calcite, wollastonite and / or graphite, which may be bound with phenolic resin systems. Thus, a phenolic resin abrasive grain mixture is formed, which may be mixed with various fillers and additives.

The contact surfaces between the reinforcing layer 6 and the abrasive layer 8a and between the two abrasive layers 8a, 8b each have a stochastic roughness profile. These adjacent scrubbing disk elements thus penetrate each other to a certain extent in the boundary region, or interlock with one another. Consequently, these scrubbing disk elements have no clear area boundaries (contact surfaces) to each other.

Between the two abrasive layers 8a, 8b, a reinforcing fabric 10 is arranged. In addition, another reinforcing fabric 10 is disposed between the reinforcing layer 6 and the abrasive layer 8a. The reinforcing fabrics 10 are each formed of a glass fiber fabric and serve the strength of the roughing disc 1. The

Reinforcing fabric 10 extend from an outer edge of the roughing disc 1 to the central recess 2 and embrace the central recess 2 annular.

In addition to the stochastic character of the contact surface, a targeted structuring of the contact surfaces can be achieved by the use of reinforcing fabrics 10 via a possible window and / or lattice structure of the reinforcing fabric 10. The reinforcing fabric 10 can penetrate at different depths into the individual layers or adjacent grinding disk elements and / or extend over a plurality of layers or grinding disk elements.

In addition, the roughing disc 1 comprises a stabilizing core 12, which circumferentially adjoins the central recess 2 around the axis of rotation 5 of the roughing disc 1, or forms the edge of the central recess 2 in sections. The stabilizing core 12 is formed by two core segments 12a, 12b and serves as a force transmission element between the two abrasive layers 8a, 8b and the connection to the drive shaft of the tool. The stabilizing core 12 is assigned to the abrasive layers 8a, 8b and has a second material mixture 18, which comprises at least one second abrasive additive 20 different from the first abrasive additive 16. The second material mixture 18 may comprise corundum, silicon carbide, zirconium corundum, sol gel, ceramic and / or diamond as a second abrasive additive. The second material mixture 18 may further comprise a mineral additive 22 which is basalt, quartz sand, WoUastonite, aluminum silicate and / or kaolin. The mineral additive 22 may have a Mohs hardness of at least 2, preferably between 7 and 9. The mineral additive 22 may have a particle size of 30 to 1000 μπι, preferably 200 to 500 μπι.

The second material mixture 18, the second abrasive additive 20 and the mineral additive 22 are shown schematically in the figure and only a portion of the stabilizing core 12, however, the second material mixture 18, the second abrasive additive 20 and / or the mineral additive 22 in the entire stabilizing core 12 may be present.

The grain of the first abrasive additive 16 and / or the grain of the second abrasive additive 20 and / or the grain of the mineral additive 22 is coated with phenolic resin systems comprising a resol / novolak mixture.

Each abrasive layer 8a, 8b is assigned a core segment 12a, 12b of the stabilization core 12. The core segment 12 a is arranged between two reinforcing fabrics 10. The core segment 12b adjoins a reinforcing fabric 10 on the tool side and is open on the workpiece side, ie uncovered by a reinforcing fabric 10. It follows that the two reinforcing fabrics 10 divide the stabilizing core 12 into two core segments 12a, 12b. The two adjacent core segments 12a, 12b are connected to each other via the reinforcing fabric 10 disposed therebetween and define the stabilizing core 12. However, the stabilizing core 12 can also be made continuous or consist of one part in the direction of the axis of rotation 5. It is conceivable that the stabilization core 12 extends over the entire height of the roughing disc or only over a partial height of the roughing disc. The stabilizing core 12 has a frustoconical cross-section, or has over its thickness in the axial direction of the roughing disc a variable radius.

In order to ensure an optimal connection to a tool, the central recess 2 is designed as a recessed hub.

LIST OF REFERENCE NUMBERS

Schrappscheibe

central recess

body

commitment

axis of rotation

reinforcing layer

a, 8b abrasive layer

0 reinforcing fabric

2 stabilization core

2a, 12b core segment

4 first material mix

6 first abrasive additive

8 second material mix

0 second abrasive additive

2 mineral additive

Claims

claims

1. roughing disc for machining material surfaces, comprising

a disk-shaped base body (3) which comprises a central recess (2), through which an axis of rotation (5) passes, for the direct or indirect connection of a drive shaft of a tool,

at least one abrasive layer (8) comprising a first material mixture comprising at least one first abrasive additive, and

a stabilizing core (12) for stabilizing the roughing disc, which is associated with the at least one abrasive layer (8a, 8b) and which is arranged circumferentially adjacent to the central recess (2), characterized in that the stabilizing core (12) comprises a second material mixture which comprises at least one second abrasive additive other than the first abrasive additive.

2. The grinding wheel according to claim 1, wherein the second material mixture comprises, as the second abrasive additive, corundum, silicon carbide, zirconium corundum, sol gel, ceramic and / or diamond.

3. grinding disc according to claim 1 or 2, wherein the second material mixture comprises a mineral additive which is basalt, quartz sand, wollastonite, aluminum silicate and / or kaolin.

4. grinding disc according to claim 3, wherein the mineral additive a

Mohs hardness of at least 2, preferably between 7 and 9 has.

5. grinding disc according to claim 3 or 4, wherein the mineral additive has a particle size of 30 to 1000 μπι, preferably 200 to 500 μιη.

6. Roughing wheel according to one of claims 1 to 5, wherein the grain of the first abrasive additive and / or the grain of the second abrasive additive and / or the grain of the mineral additive with phenolic resin systems, comprising a resol / novolak mixture, is enveloped.

7. Roughing disc according to claim 6, wherein the resol has a viscosity of 1,000 to 5,000 mPa s, preferably 1,200 to 3,500 mPa s.

8. A roughing disc according to claim 6 or 7, wherein the novolak has a content of hexamethylenetetramine of at least 9% by volume, preferably 12 to 16% by volume and a flow distance of 15 to 35 mm, preferably 17 to 26 mm.

9. Roughing wheel according to one of claims 6 to 8, wherein the novolak additionally defined amounts of other additives and / or additives of less than 20% by volume are added.

10. A roughing wheel according to any one of claims 1 to 9, wherein the base body (3) comprises a reinforcing layer (6) which carries the at least one abrasive layer (8a, 8b).

11. A roughing wheel according to any one of claims 1 to 10, wherein the contact surfaces between two of the adjacent adjacent scrubbing disk reinforcing layer (6), abrasive layer (8a, 8b) and stabilizing core (12) and / or between two adjacent abrasive layers (8a, 8b) at least partially have a stochastic roughness profile.

12. A roughing wheel according to any one of claims 1 to 1 1, wherein in at least one boundary region between two of the subsequent adjacent Schruppscheiben- elements reinforcing layer (6), abrasive layer (8a, 8b) and stabilizing core (12) and / or between two adjacent abrasive layers (8a , 8b) Reinforcing fabric (10) is arranged.

13. The grinding wheel according to claim 12, wherein the reinforcing fabric (10) is a glass and / or carbon fiber fabric.

14. A roughing wheel according to claim 12 or 13, wherein the reinforcing fabric (10) is arranged at different depths in the adjacent areas.

15. A roughing wheel according to any one of claims 12 to 14, wherein the reinforcing fabric (10) extends over the entire boundary region between two of the adjacent grinding disk elements.

16. A roughing wheel according to any one of claims 12 to 14, wherein the reinforcing fabric (10) extends at least over a portion of a boundary region between two of the adjacent grinding wheel elements.

17. A roughing wheel according to any one of claims 1 to 16, wherein the stabilizing core (12) has a cylindrical, conical, truncated, paraboloid or hyperboloidal shape.

18. Roughing wheel according to one of claims 1 to 17, wherein the stabilizing core (12) in the direction of the axis of rotation (5) is designed to be continuous.

19. A roughing wheel according to any one of claims 1 to 18, wherein the reinforcing layer (6) comprises rutile, wollastonite, calcite and basalt which are phenolic resin bonded.