• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The present invention relates to a method for producing thin, ceramic-bonded grinding bodies (2), wherein a number of thin, ceramic-bonded grinding bodies (2) are obtained from a sintered ceramic molded body (1).
    公开号:CH715030A1
    申请号:CH6802018
    申请日:2018-05-29
    公开日:2019-11-29
    发明作者:Christina Didavide Maria；Müller Matthias
    申请人:Reishauer Ag；
    IPC主号:
    专利说明:

    description
    TECHNICAL FIELD The present invention relates to a method for producing ceramic-bonded grinding wheels.
    PRIOR ART [0002] Bound grinding tools or grinding tools are used in technology in particular for surface processing. To produce the bonded grinding tools, abrasive grains, for example those based on aluminum oxide or corundum, silicon carbide, diamond or CBN, are mixed with a binder and optionally other additives, such as e.g. Fillers, abrasive substances, pore formers or temporary adhesives, processed into a mixture, which is then pressed in a mold to the desired shape. The resulting green body is then dried, optionally freed of the added pore formers at suitable temperatures and then fired ceramic.
    Depending on the application, the grinding tools have different diameters and thicknesses, the amount of work for the production of individual grinding wheels is almost independent of how thick a disc is or what diameter it has. Thin grinding media can only guarantee a low removal during grinding. The effort for the production of thin grinding wheels, calculated on the removal that can be achieved with these grinding wheels, is relatively high compared to thicker grinding wheels. Since the work involved in the production of grinding wheels makes up a large part of the manufacturing costs, the use of thin grinding wheels is comparatively expensive. Manufacturing costs can be reduced through automation, but this only pays off if large quantities of panes can be produced.
    The object of the present invention is therefore to find a method or ways to reduce the costs for the production of thin abrasive bodies, without there being any loss of quality. When dealing with this problem, the inventors of the present application had the basic idea of first producing thick cylindrical moldings in large molds and then dividing them into individual thin grinding media. The first attempts were to cut several thin slices from a cylinder. For this purpose, a cylindrical base body for conventional ceramic bonded abrasives with corundum as the abrasive grain was manufactured. After the sintering, the cylinder was cut into slices with the aid of a diamond saw, and the thin grinding bodies thus obtained were rotated plane-parallel and then subjected to a grinding test. The grinding tests showed that the quality of the thin grinding wheels obtained in this way is comparable to that of conventionally produced single grinding wheels. However, it soon became clear that cutting the cylinders into individual disks is relatively costly and time-consuming, so that the original goal of producing thin grinding bodies inexpensively could only be achieved to a limited extent in this way.
    Building on the basic idea, the inventors of the present application then developed the idea further and produced several thin grinding wheels in one pressing process in a single mold by filling the mass of abrasive grain, binder and additives required for a thin grinding body into the mold , have the mass smoothed and covered with an intermediate disc, in order to then fill in the mass for the next grinding wheel. This method also provided high-quality grinding tools, but the cost savings are limited, since the grinding tools have to be processed as individual grinding tools after the pressing process and thus only the pressing of the grinding tools has been rationalized. In addition, inserting the washers requires additional handling, which further reduces the cost savings.
    Finally, the preferred solution to the problem was to form a thin intermediate layer by sprinkling inert particles onto the mass filled and smoothed for the desired individual abrasive body. The mass for the next individual abrasive body was then poured onto the intermediate layer, which after smoothing was in turn covered with an intermediate layer made of inert particles. This process was repeated until the mold was completely filled, the mass for the last individual grinding body no longer being covered. When pressing with high pressure, the layered shaped body is compressed in such a way that it can be removed as a coherent body from the press mold and then dried and sintered or fired. The sintered molded body obtained in this way is built up in layers, the cohesion of the thin intermediate layers made of inert particles which do not contain a binder being not very pronounced. It should be noted that the radial friction between the individual grinding wheels is very large, so that the grinding wheels are difficult to move against one another but can be easily lifted off. The desired individual grinding bodies can now be removed from the sintered molding obtained in this way at the level of the intermediate layers without great mechanical outlay. The grinding wheels then only have to be rotated plane-parallel in order to be used as a thin grinding wheel.
    [0007] Layered abrasive bodies are described in numerous documents. For example, EP 1 189 731 B1 describes a method and a device for producing thin abrasive bodies by pressing at least one layer which is formed from abrasive grains and two layers which contain no abrasive grains and which surround the grinding wheel, the two layers without abrasive grains are provided as reinforcing layers.
    CH 715 030 A1 [0008] DE 3 442 230 C2 describes a method for producing an abrasive body with a plurality of abrasive layers, between each of which there is a grinding-inactive, vibration-damping damping layer, which preferably consists of a polymer. In this case, it is a matter of providing a method for producing soundproofed grinding wheels.
    [0009] DE 10 062 473 A1 describes a honing ring and a method for producing a honing ring, the base body of the honing ring being formed by a stack of disks. The individual disks are firmly bonded to one another with adhesive or binder layers to form the desired honing ring.
    DE 4 545 308 A1 describes multi-layered abrasive bodies which are built up in layers for sound absorption with the interposition of at least one layer of vibration-damping materials, the layer of vibration-damping materials being brought into the form in the form of a fine-grained, free-flowing powder and / or granulate ,
    All of the documents cited above are aimed at the production of multi-layered grinding wheels, the multi-layered structure always having a technical background and thus being an indispensable part of the finished grinding wheel when it is used. A multilayered grinding wheel, which serves as a base for the production of individual grinding wheels, in order to produce thin grinding wheels in this way at low cost, could not be determined in the prior art.
    The above object is achieved according to the invention by a method for producing ceramic-bonded grinding wheels, in a first step a sufficient mass for at least one thin individual grinding wheel is given from at least a mixture of grinding grains and binder in a mold. The mixture can optionally additionally contain grinding-active and / or grinding-inactive fillers, additives and pore formers. The mass is pressed in the mold with the aid of a press, and the green body obtained in this way is then sintered into a shaped body. After cooling, the sintered shaped body is divided into individual disks.
    According to the method described above, an oversized grinding body or cylindrical shaped body is thus produced in a press mold and then divided into thin individual disks, the process steps described above not initially including a layered structure of the cylindrical shaped body. The division can also be done, for example, by sawing with a diamond saw.
    Preferably, however, the at least one mixture is poured into the mold in portions, with a portion sufficient for a single abrasive body first being poured into the mold, the mass then being smoothed and then covered with an intermediate layer and this process being repeated so often, until the mold is filled.
    In one embodiment of the method according to the invention, the intermediate layer is formed by inserting an intermediate disk. The intermediate disc can be made of any material that does not react with the abrasive grain mixture. For example, thin metal sheets can be used, which are relatively inexpensive to manufacture and can be reused without any problems.
    A particularly preferred embodiment of the present invention, however, provides that the intermediate layer is formed by sprinkling inert particles onto the mass filled and smoothed for the desired individual abrasive body. Suitable inert particles are, for example, loose corundum grains which are scattered onto the mass filled and smoothed for the desired individual abrasive body. The layer thickness of the intermediate layer made of loose corundum grains is advantageously 0.5 mm to 5 mm, preferably approximately 1 mm. The layer thickness must be chosen thick enough that the adjacent grinding wheels are not glued, and at the same time small enough so that the multi-layer molded body holds together after pressing and can be processed as a whole. The grain size of the loose corundum grains is advantageously F60 to F1000 according to FEPA.
    Of course, any other particles can be used for the intermediate layer, as long as they show no reaction with the abrasive grain-binder mixture. However, the use of corundum lends itself, since the method according to the invention is preferably intended for the production of ceramic-bonded grinding wheels with grinding grains based on aluminum oxide or corundum.
    The method is not limited to the production of grinding wheels with the same thickness and composition, but it can be produced in a pressing process, thin grinding wheels with different thickness (thickness), which are then sintered as a coherent shaped body in a sintering cycle. It is even possible to produce grinding media with different compositions using the method according to the invention if corresponding different mixtures are poured into the mold in portions and separated with an intermediate layer. Provided that the green bodies obtained from the different mixtures can be fired with the same sintering cycle, a layer of loose corundum can preferably be used again as an intermediate layer. If the respective green bodies require different sintering cycles, it is advisable to insert metal sheets as intermediate layers so that the green bodies can be processed separately after the pressing process. It should be noted that in principle it is of course also possible to choose different intermediate layers for a pressing process if, for example, different grinding wheels are to be produced.
    CH 715 030 A1
    BRIEF DESCRIPTION OF THE DRAWINGS Preferred embodiments of the invention are described below with reference to drawings, these being intended only as explanations and not to be interpreted as restrictive. In the drawings:
    Figure 1 is a perspective view of the individual components of an assembly for the burning process.
    Fig. 2 is an exploded view of Fig. 1;
    Fig. 3 is a perspective view from above of Fig. 1;
    4 shows a schematic flow chart for the method according to the invention.
    DESCRIPTION OF PREFERRED EMBODIMENTS Figure 1 shows the individual components of an assembly for the firing process. This combination comprises a shaped body 1 which is constructed from a plurality of abrasive bodies 2 and intermediate layers 3. The compilation also includes a coaster 4 on which the molded body 1 is stored during the firing process and during transport to and from the furnace. For a better overview, the intermediate layer 3 and the grinding body 2 were also shown separately in FIG. 1. Depending on the embodiment of the present invention, the intermediate layer 3 can be formed from loose corundum grains or as an intermediate disc. The coaster 4 is a refractory ceramic carrier that can be used again for the next firing cycle after the firing process.
    2 shows, from a side perspective, a compilation for a firing process of a multilayer sintered shaped body 1, which consists of a total of four grinding bodies 2, each of which is connected to one another via an intermediate layer 3. In the present case, the intermediate layer 3 can be formed, for example, from loose corundum grains, which are compressed to such an extent during pressing that the intermediate layer 3 holds the molded body 1 together without an additional binder. In comparison to the abrasive bodies 2, the intermediate layer 3 is made relatively thin, so that it is ensured that the molded body 1 holds together as a whole and can be processed accordingly. However, the stability of the intermediate layer 3 is low enough that the individual abrasive bodies 2 can be lifted from the stack and separated from one another after the sintering with a low mechanical load along the intermediate layer 3. The intermediate layer 3 thus acts like a perforation. The sintered molded body 1 is mounted on a ceramic coaster 4, on which it is placed after the pressing, in order then to be moved into the sintering furnace.
    3 shows the sintered shaped body 1 from FIG. 2 from a slightly different perspective, the viewer looking into the interior of the stack of grinding bodies in a top view. The multi-layer molded body 1 constructed from abrasive body layers 2 and intermediate layers 3 is deposited on a ceramic coaster 4, which is provided as a carrier for the transport of the green body from the press to the sintering furnace.
    In Fig. 4, a simplified flow chart for the inexpensive manufacture of thin ceramic bonded grinding tools is illustrated. First of all, abrasive grains, a ceramic binder, a pore former and optionally adhesives and additives are mixed (step 21). The resulting mass is then removed from the mixer, sieved and placed in a mold (step 22). The filling into the mold is preferably carried out in portions, whereby a portion sufficient for a single grinding wheel is first filled into the mold, the mass is then smoothed and then covered with an intermediate layer, this process being repeated until the mold is filled. The filled mass together with the intermediate layers is then pressed with a press (step 23). The green body obtained in this way is optionally dried and fired in an oven (step 24). After the firing and cooling, the grinding bodies are separated from the sintered shaped body, for example by slight mechanical stress along the intermediate layer, and separated (step 25).
    Production of grinding wheels In a grinding test it should be checked whether the changed production process has an influence on the grinding performance. For this purpose, the same raw material constituents shown in Table 1 were used for all the grinding tools tested, so that the grinding test enables a direct comparison of the grinding tools produced under different conditions. The quantities of the individual components are based on the abrasive grain (100%).
    Table 1
    raw material characterization Quantity (% by weight) abrasive grain corundum 100
    CH 715 030 A1
    raw material characterization Quantity (% by weight) ceramic binder oxide mixture 11 Glue Polymer solution 2 additives Various additives 3 pore formers charcoal 6
    The components were introduced into a drum mixer and mixed in 23 mixing steps for about 60 minutes until a homogeneity and pourability of the mass was evident. The mass was then removed from the mixer and sieved. The sieved mass was placed in a mold to produce a comparison disk and pressed in a form-fitting manner with a press at pressures of 90 bar. The green body thus obtained had the dimensions (diameter x height x bore) 280 x 35 x 157 mm and was fired in a furnace up to a maximum temperature of 1200 ° C. using a predetermined firing program.
    The same mass was added in portions to a higher mold with the same diameter, a sufficient portion for a single abrasive was filled into the mold, the mass was then smoothed and then covered with an intermediate layer and this process was repeated until the mold was filled with a mass for a total of four grinding wheels. A layer of white corundum in the grain F80 with a layer thickness of approx. 1 mm was chosen as the intermediate layer.
    Grinding Tests The finished abrasive articles had the properties described in Table 2 below. The pattern A was made in a conventional way as a single disc in a small form. Pattern B was an edge piece from the sintered multilayer molded body. Pattern C was taken from the center of the sintered multilayer molded body. To test the disks, the limit chip removal volume or the equivalent chip thickness h eq _ t h up to the occurrence of grinding burn was determined in a first step and in a second step the limit chip removal volume or the equivalent chip thickness h eq v with regard to exceeding the permissible wear limit was determined. Both values are also recorded in Table 2.
    Table 2
    specimen A (comparison) B (edge) C (middle) Dimensions (mm) 275 x 30 x 160 275 x 30 x 160 275 x 30 x 160 Weight (g) 3907 3921 3911 Density (g / cm 3 ) 1881 1874 1897 Sanding burn limit (%) * 103 105 102 Wear limit (%) ** 105 110 104
    * Grinding burn limit = maximum achievable equivalent chip thickness h eq _th, which can be used without grinding burn, ie without thermomechanical damage to the surface layer.
    ** Wear limit = maximum achievable equivalent chip thickness h eq v > which can be used if a given wear criterion is maintained.
    The discs were tested on a Reishauer machine RZ 260 using cooling oil and a diamond dressing tool. A test wheel made of 16MnCr5 was selected as the workpiece.
    In the grinding burn test, systematic enlargement of the axial feed (Z feed) was used in three stages with three leveling strokes, one roughing stroke and one finishing stroke with otherwise identical cutting values and cutting conditions. In this way, a uniform infeed could be ensured in the 2nd stage for the roughing stroke. The grinding fire detection was carried out after the finishing stroke (3rd stage) using nital etching.
    The wear test was carried out with a comparable technology, with the second stage in the roughing stroke working with a variable Z-feed and after the finishing stroke (third stage) the wear in the area of use of the grinding worm was determined during the roughing stroke. If a shape deviation of the profile fff> 6 μm according to DIN 3960 is exceeded for a given grinding speed, the performance limit is reached.
    CH 715 030 A1 [0033] It can be stated that several thin, ceramic-bonded abrasive bodies can be manufactured in one pressing operation without any loss of quality. The manufacturing costs per grinding body can be significantly reduced, in particular due to the rationalization of the pressing process and the sintering step. When using loose corundum as an inert particle for the intermediate layer, a cost saving of up to 30% can be realized.
    REFERENCE SIGN LIST [0034]
    moldings
    abrasives
    interlayer
    coaster
    Process step (mixing)
    Process step (filling)
    Process step (pressing)
    Process step (sintering)
    Process step (separating)
    权利要求:
    Claims (8)
    [1]
    claims
    1. A process for producing ceramic-bonded grinding wheels (2), wherein
    - a mass of at least one mixture of abrasive grains and binder sufficient for a plurality of individual abrasive bodies (2) is placed in a mold, the mixture optionally additionally containing grinding-active and / or grinding-inactive fillers, additives and pore formers,
    - The mass is pressed in the form with the help of a hydraulic press and
    - The green body thus obtained is then sintered into a shaped body (1), characterized in that the sintered shaped body (1) is divided into individual grinding bodies (2) after cooling.
    [2]
    2. The method according to claim 1, characterized in that the filling of the at least one mixture into the mold is carried out in portions, with a portion sufficient for an individual grinding body (2) being filled into the mold, the mass being subsequently smoothed and then with an intermediate layer ( 3) is covered and this process is repeated until the mold is filled.
    [3]
    3. The method according to claim 1 or 2, characterized in that the intermediate layer (3) is formed by inserting an intermediate washer.
    [4]
    4. The method according to claim 1 or 2, characterized in that the intermediate layer (3) is formed by sprinkling inert particles onto the mass filled and smoothed for the desired individual grinding body (2).
    [5]
    5. The method according to claim 4, characterized in that the intermediate layer (3) made of inert particles has a layer thickness of 0.5 to 5 mm.
    [6]
    6. The method according to claim 4, characterized in that the intermediate layer (3) made of inert particles has a layer thickness of approximately 1 mm.
    [7]
    7. The method according to any one of claims 4 to 6, characterized in that the intermediate layer (3) is formed by sprinkling loose corundum grains onto the mass filled and smoothed for the desired individual grinding body (2).
    [8]
    8. The method according to claim 7, characterized in that the grain size of the loose corundum grains is F60 to F1000 according to FEPA.
    CH 715 030 A1
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    同族专利:
    公开号 | 公开日
    CH715030B1|2020-09-30|
    EP3590658A1|2020-01-08|
    CH715030A9|2020-01-15|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US4807402A|1988-02-12|1989-02-28|General Electric Company|Diamond and cubic boron nitride|
    DE202007019685U1|2006-03-06|2015-08-03|Saint-Gobain Abrasifs Technologie Et Services|Fine grinding wheel for deburring|
    WO2010129813A2|2009-05-06|2010-11-11|Smith International, Inc.|Methods of making and attaching tsp material for forming cutting elements, cutting elements having such tsp material and bits incorporating such cutting elements|
    DE3442230C2|1984-11-19|1991-04-04|Tyrolit-Schleifmittelwerke Swarovski Kg, Schwaz, Tirol, At|
    FR2794676B1|1999-06-09|2001-08-10|Seva|METHOD AND PLANT FOR MANUFACTURING ABRASIVE WHEELS, AND GRINDER MANUFACTURED BY THIS PROCESS|
    DE10062473B4|2000-12-14|2004-06-17|Erich Haug|Honing ring and method for producing a honing ring base body|
    法律状态:
    2020-01-15| PK| Correction|Free format text: BERICHTIGUNG: RECHERCHENBERICHT. |
    优先权:
    申请号 | 申请日 | 专利标题
    CH00680/18A|CH715030B1|2018-05-29|2018-05-29|Process for the production of thin abrasive articles.|CH00680/18A| CH715030B1|2018-05-29|2018-05-29|Process for the production of thin abrasive articles.|
    EP19173758.4A| EP3590658A1|2018-05-29|2019-05-10|Method for producing thin grinding bodies|
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