RESIN BONDED CUT-OFF TOOL

Abstract

The invention relates to a resin bonded cut-off tool. The resin bonded cut-off tool comprises rod shaped sintered bauxite abrasives, wherein an amount of the rod shaped sintered bauxite abrasives is at least 10% to 90% by weight, based on 100% by weight of a Grinding Active Matrix (GAM) of the cut-off tool. The resin bonded cut-off tool comprises further a bonding agent in an amount of 10% to 40% by weight, based on 100% by weight of the GAM of the cut-off tool and fused and/or sintered abrasives in an amount sufficient to bring the GAM of the cut-off tool to 100% by weight.

Claims

1. Resin bonded cut-off tool (100), particularly resin bonded cut-off wheel (101), comprising rod shaped sintered bauxite abrasives (10), wherein an amount of the rod shaped sintered bauxite abrasives (10) is at least 10% to 90% by weight, based on 100% by weight of a Grinding Active Matrix (GAM) of the cut-off tool (100); bonding agent (20) in an amount of 10% to 40% by weight, based on 100% by weight of the GAM of the cut-off tool (100); and fused and/or sintered abrasives (30) in an amount sufficient to bring the GAM of the cut-off tool (100) to 100% by weight.

2. Resin bonded cut-off tool (100) according to claim 1, wherein the rod shaped sintered bauxite abrasives (10) comprise aluminum oxide (Al.sub.2O.sub.3) (11) in an amount of 80% to 98% by weight, based on 100% by weight of the rod shaped sintered bauxite abrasives (10); a mixture of ferric oxide (Fe.sub.2O.sub.3) (12) and titanium dioxide (TiO.sub.2) (13) in an amount of 5% to 15% by weight, based on 100% by weight of the sintered bauxite abrasives (10); silicon dioxide (SiO.sub.2) (14) in an amount of 0.2% to 6% by weight, based on 100% by weight of the sintered bauxite abrasives (10).

3. Resin bonded cut-off tool (100) according to claim 1, wherein the rod shaped sintered bauxite abrasives (10), the bonding agent (20) and the fused and/or sintered abrasives (30) are arranged within a fabric and/or a plate (40).

4. Resin bonded cut-off tool (100) according to claim 1, wherein the resin bonded cut-off-tool (100) comprises a fixing element (50).

5. Resin bonded cut-off tool (100) according to claim 1, wherein the bonding agent (20) comprises a phenol-formaldehyde resin.

6. Resin bonded cut-off tool (100) according to claim 2, wherein the rod shaped sintered bauxite abrasives (10) comprise grains with a grain size of smaller than 15.0 micrometer.

7. Resin bonded cut-off tool (100) according to claim 2, wherein the rod shaped sintered bauxite abrasives have a diameter between 0.3 and 1.6 mm and an average length between 0.3 to 4.0 mm.

Description

[0039] Table 4 shows an exemplary list of the used raw material in the test sets 1 to 4.

TABLE-US-00004 TABLE 4 Exemplary list of raw materials of the resin bonded cut-off tools of the test sets 1 to 4. ID Function Raw material name and supplier WR Abrasive Sinter Morundum SR-1, Showa Denko Grade 24: diameter 0.65 mm, average length 1.5 mm BR Abrasive Sinter Morundum SM, Showa Denko Grade 24: diameter 0.79 mm, average length 1.9 mm BFA Abrasive Alodur RBT9, Imerys Fused Minerals Bonding Phenol-formaldehyde resin Prefere 825174G, prefere resins agent (liquid) (liquid) Bonding agent Phenol-formaldehyde resin Prefere 828528G, prefere resins (solid) (solid) Filler Tribotecc-Pyrox rot 325, Tribotecc GmbH Filler Potassium Aluminium Fluoride (PAF), KBM Affilips B.V. Filler Tribotecc-GWZ 100P, Tribotecc GmbH Pigment Luvomaxx LB/S, Lehmann&Voss&Co. Glass fabric Reinforcement Glasgewebe-Ronden 1970 402/41, Tissa Glasweberei AG Metal ring Bore reinforcement ZU22/b 60 40, 8 4, 5, Omes s.r.i.

[0040] FIG. 1 schematically illustrates a resin bonded cut-off tool, particularly a resin bonded cut-off wheel, according to an embodiment of the invention;

[0041] FIG. 2 schematically illustrates a pie chart of an exemplary composition of rod shaped sintered bauxite abrasives according to an embodiment of the invention;

[0042] FIG. 3 shows a bar graph illustrating a cutting performance of resin bonded cut-off tools comprising an abrasive fraction based on 100% black rod abrasive (BR, test set 2) in comparison to such comprising 100% white rod abrasive (WR, test set 1) when applying a specific cut rate of 3.5 cm.sup.2/s and cutting carbon steel (ST37) or stainless steel (INOX);

[0043] FIG. 4 shows a bar graph illustrating a cutting performance of resin bonded cut-off tools comprising an abrasive fraction based on 100% black rod abrasive (BR, test set 2) in comparison to such comprising 100% white rod abrasive (WR, test set 1) when applying a specific cut rate of 5.0 cm.sup.2/s and cutting carbon steel (ST37) or stainless steel (INOX); and

[0044] FIG. 5 shows a bar graph illustrating a cutting performance of resin bonded cut-off tools comprising an abrasive fraction based on 50% black rod abrasive and 50% brown fused alumina (BR+BFA, test set 4) in comparison to such comprising 50% white rod abrasive and 50% brown fused alumina (BR, test set 3) when applying a specific cut rate of 3.5 cm.sup.2/s and cutting carbon steel (ST37) or stainless steel (INOX).

[0045] Abbreviations: ST37: carbon steel S235JR/1.0038, INOX: stainless steel X5CrNi18-10/1.4301

[0046] The test sets 1, 2, 3 and 4 (see table 3) illustrated in the corresponding FIGS. 3, 4 and 5 are respectively normalized to 100% to the cutting performance of the resin bonded cut-off tools comprising the rod shaped sintered alumina (white rods).

[0047] In the figures, like reference numerals denote like or functionally like components, unless indicated otherwise. Any directional terminology like top, bottom, left, right, above, below, horizontal, vertical, back, front, and similar terms are merely used for explanatory purposes and are not intended to delimit the embodiments to the specific arrangements as shown in the figures.

[0048] Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations may be substituted for the specific embodiments shown and described without departing from the scope of the present invention. Generally, this application is intended to cover any adaptations or variations of the specific embodiments discussed herein.

[0049] FIG. 1 schematically illustrates a resin bonded cut-off tool, particularly a resin bonded cut-off wheel, according to an embodiment of the invention.

[0050] The resin bonded cut-off tool 100 illustrated as resin bonded cut-off wheel 101 is schematically illustrated in FIG. 1. The resin bonded cut-off tool 100 comprises rod shaped sintered bauxite abrasives 10 (O-shape), wherein an amount of the rod shaped sintered bauxite abrasives 10 (O-shape) is at least 10% to 90% by weight, based on 100% by weight of a GAM of the cut-off tool. The resin bonded cut-off tool 100 comprises a bonding agent 20 in an amount of 10% to 40% by weight, based on 100% by weight of the GAM of the cut-off tool 100 and fused and/or sintered abrasives 30 (triangular shape) abrasives in amount sufficient to bring the GAM of the cut-off tool to 100% by weight. The bonding agent 20 is illustrated by the dotted area in FIG. 1.

[0051] The resin bonded cut-off tool can comprise at least a fabric 40, for example two glass fabrics, wherein the rod shaped sintered bauxite abrasives 10, the bonding agent 20 and the fused and/or sintered abrasives 30 are arranged within the at least one fabric 40. The resin bonded cut-off tool 100 can also comprise a fixing element 50, for example a metal ring, wherein the fixing element 50 can be suitable to reinforce a bore of the resin bonded cut-off wheel.

[0052] FIG. 2 schematically illustrates a pie chart of an exemplary composition of rod shaped sintered bauxite abrasives according to an embodiment of the invention.

[0053] FIG. 2 is a non-limiting example of a composition of the here described rod shapes sintered bauxite abrasives 10. The rod shapes sintered bauxite abrasives 10 comprise aluminum oxide (Al.sub.2O.sub.3) 11 in an amount of 80% to 98% by weight, preferably of 86% to 88% by weight, more preferably 87% by weight, based on 100% by weight of the rod shaped sintered bauxite abrasives. The rod shaped sintered bauxite abrasives further comprise a mixture of ferric oxide (Fe.sub.2O.sub.3) 12 and titanium dioxide (TiO.sub.2) 13 in an amount of 5% to 15% by weight, preferably of 9% to 11% by weight, more preferably 10% by weight, based on 100% by weight of the sintered bauxite abrasives and silicon dioxide (SiO.sub.2) 14 in an amount of 0.2% to 6% by weight, preferably of 2% to 4% by weight, more preferably 3% by weight, based on 100% by weight of the sintered bauxite abrasives.

[0054] FIG. 3 shows a bar graph illustrating a cutting performance of resin bonded cut-off tools comprising an abrasive fraction based on 100% black rod abrasive (BR, test set 2, right side of FIG. 3 with hatched bars) in comparison to such comprising 100% white rod abrasive (WR, test set 1, left side of FIG. 3) when applying a specific cut rate of 3.5 cm.sup.2/s and cutting carbon steel (ST37) or stainless steel (INOX). FIG. 4 shows further test set as in shown in FIG. 3 with the difference that the specific cut rate has been increased to 5.0 cm.sup.2/s.

[0055] FIG. 5 shows a bar graph illustrating a cutting performance of resin bonded cut-off tools comprising an abrasive fraction based on 50% black rod abrasive and 50% brown fused alumina (BR and BFA, test set 4, right side of FIG. 5 with hatched bars) in comparison to such comprising 50% white rod abrasive and 50% brown fused alumina (BR, test set 3, left side of FIG. 5) when applying a specific cut rate of 3.5 cm.sup.2/s and cutting carbon steel (ST37) or stainless steel (INOX).

[0056] The cutting performance of the exemplary resin bonded cut-off tools was evaluated by using a stationary cut-off machine (Trennblitz, self-construction, motor power 22 kW), operating at a peripheral work surface speed of 80 m/s under dry conditions. The tests were conducted with a specific cut rate of 3.5 cm.sup.2/s and a specific cut rate of 5 cm.sup.2/s. The workpieces were round slabs in diameter 40 mm of carbon steel type ST37 (S235JR, 1.0038, from Salzgitter Gruppe) and stainless steel type Nirosta 4301 (X5CrNi 18-10, 1.4301, from Krupp Edelstahlprofile). After conducting 20 cuts in full cut each G.sub.A-factor as an index of the cutting performance of the cut-off wheel was evaluated. The G.sub.A-factor is calculated from the ratio of the cut workpiece area (Aw) and the worn tool area (Avs):

G.sub.A=Aw/Avs

[0057] FIGS. 3, 4 and 5 show that [0058] the tool performance depends on the type of rod shaped abrasive, with respect to the cut-off tools tested it decreases in the order black rod (sintered bauxite)>white rod (sintered alumina). In other words the black rods have an increased cutting performance; and [0059] the content of rod shaped abrasive in the abrasive fraction of the resin bonded cut-off tool is direct proportional with the tool/cutting performance showing the best performance for a fraction comprising 100% rod shaped sintered bauxite abrasives.

[0060] The results for the G.sub.A-factor normalized to the G.sub.A-factor of tools comprising the corresponding white rod variant are shown in FIGS. 3, 4 and 5. The values reflect the average value of two experimental wheels tested each under the same and specified test conditions.

[0061] In reference to the test results the 100% black rod variant 10 (test set 2; hatched bars) shows a cutting performance increase of +34-50% towards the corresponding white rod variant 80 (test set 1) when applying a specific cut rate of 3.5 cm.sup.2/s (FIG. 3) and +8-9% when applying a specific cut rate of 5 cm.sup.2/s (FIG. 4).

[0062] A cutting performance increases as well, when blending the rod shaped abrasive 10, 80 with brown fused alumina 90 (test set 4). In comparison to the corresponding white rod variant (test set 3) a 7-26% higher G.sub.A-factor was observed, whereas the extent depends on the cut steel type (FIG. 5).

[0063] Considering the steel types (ST37 or INOX) cut according to the described test set-up it has been found out that the test sets comprising black rod abrasives show higher cutting performance when cutting carbon steel and applying a lower specific cut rate. See FIGS. 3 and 5 a 16-19% higher G.sub.A-factor was measured for carbon steel at a specific cut rate of 3.5 cm.sup.2/s.

[0064] In the foregoing detailed description, various features are grouped together in one or more examples or examples with the purpose of streamlining the disclosure. It is to be understood that the above description is intended to be illustrative, and not restrictive. It is intended to cover all alternatives, modifications and equivalents. Many other examples will be apparent to one skilled in the art upon reviewing the above specification.

[0065] The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. In the appended claims and throughout the specification, the terms having and in which are used as the plain-English equivalents of the respective terms comprising and wherein, respectively. Furthermore, a or one does not exclude a plurality in the present case.

[0066] Due to the test results it can be considered that more and more material removing machining tools comprise rod shaped sintered bauxite abrasives. Rod shaped sintered bauxite abrasives are a promising material for cutting tools with an expected ascending market share.