Roughing Disc Having a Backing Layer

Abstract

A roughing disc for machining material surfaces, which may have a disc-shaped main body having a tool side, which can face a tool, and a workpiece side, which can face a workpiece, the main body having a central opening through which an axis of rotation passes and which serves for direct or indirect attachment of a drive shaft of the tool, a disc-shaped backing layer disposed on the tool side, at least one abrasive layer, and a separating layer between adjacent layers. The backing layer may be made of a material mixture that is free of abrasive additives and that has at least one mineral additive.

Claims

1. A roughing disc for machining material surfaces, comprising: a disc-shaped main body having a tool side, which can face a tool, and a workpiece side, which can face a workpiece, the main body comprising a central opening through which an axis of rotation passes and which serves for direct or indirect attachment of a drive shaft of the tool, a disc-shaped backing layer disposed on the tool side, at least one abrasive layer, and a separating layer between adjacent layers, wherein the backing layer is made of a material mixture that is free of abrasive additives and that comprises at least one mineral additive.

2. The roughing disc according to claim 1, wherein the mineral additive is selected from the group consisting of basalt, quartz sand, wollastonite, aluminum silicate, kaolin, and combinations thereof.

3. The roughing disc according to claim 1, wherein the mineral additive has a Mohs hardness of preferably between 7 and 9.

4. The roughing disc according to claim 1, wherein the mineral additive has a grain size of 200 to 500 μm.

5. The roughing disc according to claim 1, wherein the grain of the mineral additive is covered in phenolic resin systems comprising a resol/novolak mixture.

6. The roughing disc according to claim 5, wherein the resol has a viscosity of 1200 to 3500 mPa.Math.s.

7. The roughing disc according to claim 5, wherein the novolak has a hexamethylenetetramine content of 12 to 16 vol %, and a flow length of 17 to 26 mm.

8. The roughing disc according to claim 5, wherein defined amounts of other additives and/or aggregates of less than 20 vol % are additionally added to the novolak.

9. The roughing disc according to claim 1, wherein the separating layer is a glass fabric layer.

Description

[0019] The single figure of the drawing shows a section through a roughing disc according to the invention.

[0020] Roughing disc 1 illustrated in the drawing has a disc-shaped main body 3 having a layered structure and an outer radius a. Main body 3 has a tool side 13, which can face a tool, and a workpiece side 12, which can face a workpiece. Main body 3 comprises a central opening 2 through which an axis of rotation 5 passes. Axis of rotation 5 is located in the center of rotation of roughing disc 1. An insert 4 for attaching roughing disc 1 to a drive shaft of a tool is disposed in opening 2. A backing layer 6 is disposed at tool side 13 of roughing disc 1, which faces the tool.

[0021] Backing layer 6 comprises a mixture that is free of abrasive additives and that comprises at lest one mineral additive. The mineral additive can be basalt, quartz sand, wollastonite, aluminum silicate and/or kaolin. The mixture of the at least one backing layer can also comprise different additives from this group. Moreover, the additive can have a Mohs hardness of at least 2, preferably between 7 and 9. The grain size of the additive can be between 30 and 1000 μm, preferably between 200 to 500 μm. The grains of the additive can be covered in phenolic resin systems, wherein the phenolic resin system can comprise a resol/novolak mixture. The resol can have a viscosity of 1000 to 5000 mPa.Math.s, preferably 1200 to 3500 mPa.Math.s. The novolak can have a hexamethylenetetramine content of at least 9 vol %, preferably 12 to 16 vol %, and a flow length of 15 to 35 mm, preferably 17 to 26 mm. Additionally, the novolak can comprise additional defined amounts of other additives and/or aggregates of less than 20 vol %. Thus, backing layer 6 has high strength. It can also comprise a mesh-like inlay in order to further increase the stability of roughing disc 1.

[0022] Moreover, roughing disc 1 has two abrasive layers 8a, 8b which are stacked in the direction of axis 5 and which are disposed on workpiece side 12. Abrasive layers 8a, 8b can comprise abrasive grains, such as regular brown fused alumina and derivatives, blue fired alumina, white fused alumina, zirconia alumina, silicon carbide, ceramic grain, pink fused alumina, and/or monocrystalline alumina. Additionally, the abrasive layers can comprise supporting fillers, such as poly aluminum fluoride, cryolite, pyrite, calcite, wollastonite, and/or graphite, which can be bound by phenolic resin systems. Thus, a phenolic-resin abrasive grain mixture is formed, which can be blended with various fillers and additives.

[0023] A separating layer, which is a glass fabric layer 10, is disposed between the two abrasive layers 8a, 8b. Another glass fabric layer 10 is disposed between backing layer 6 and abrasive layer 8a adjacent to backing layer 6. Glass fabric layers 10 act as separating layers and serve the strength of roughing disc 1. Glass fabric layers 10 extend from an outer edge 15 of roughing disc 1 to central opening 2 and surround central opening 2 annularly.

[0024] To ensure optimal connection to a tool, central opening 2 is realized as a recessed hub.