EP3558566A1

EP3558566A1 - Method for producing a green body layer by layer from pulverous material by means of insert elements arranged in a defined manner

Info

Publication number: EP3558566A1
Application number: EP17804209.9A
Authority: EP
Inventors: Maria Zivcec; Robert Spring; Roland Schneider
Original assignee: Hilti AG
Current assignee: Hilti AG
Priority date: 2016-12-22
Filing date: 2017-11-29
Publication date: 2019-10-30
Also published as: US20200122354A1; WO2018114256A1; CN110035849B; JP2020503456A; KR20190099447A; US11155003B2; EP3338917A1; CN110035849A; JP6900489B2

Abstract

The invention relates to a method for producing a green body (10) layer by layer from pulverous material by means of insert elements, which are arranged at defined positions in the pulverous material, wherein the green body (10) is divided in a construction direction (16) into N, N ≥ 2, successive cylindrical cross-sectional regions (11, 12, 13, 14, 15) of a two-dimensional cross-sectional area and a layer thickness. In the cross-sectional regions of the green body (10) that comprise the defined positions for the insert elements, setting regions for the insert elements are defined and, before the insert elements are arranged in the pulverous material, loose powder particles that surround the setting regions are at least partly bonded to each other.

Description

Process for the layered production of a green compact of powdered material with defined arranged insert elements

Technical area

The present invention relates to a method for the layered production of a green compact of powdery material with defined arranged insert elements according to the preamble of claim 1. Prior art

Abrasive machining tools, such as drill bits, saw blades, cutting wheels or grinding wheels, comprise machining segments which are fastened to a tubular or disk-shaped base body. Depending on the machining process of the abrasive machining tool, the machining segments are referred to as drilling segments, saw segments, separating segments or abrasive segments and summarized under the term "machining segments". The processing segments are constructed of powdery material and cutting elements in the form of hard particles. Here, a distinction is made between machining segments with randomly distributed hard material particles and machining segments with defined hard material particles. In processing segments with randomly distributed hard material particles, the powdery material and the hard material particles are mixed and filled into a suitable mold and first shaped into a green compact by cold pressing. In processing segments with defined arranged hard material particles, the green body is built up layer by layer of powdery material, in which the hard material particles are placed at defined positions. The green bodies are compacted into usable processing segments in the case of randomly distributed hard material particles and defined hard material particles by hot pressing and / or sintering.

Machining segments with randomly distributed hard material particles have several disadvantages: Since the hard material particles are also on the surface of the green compacts, the tool molds required for cold-pressing the green compacts are subject to high wear. In addition, the distribution of the hard material particles in the green body does not correspond to the application technically optimal distribution. The disadvantages of machining segments with randomly distributed hard material particles mean that machining segments with defined hard material particles are predominantly used for high-quality machining tools despite the higher costs. EP 0 452 618 A1 describes a known method for the layered production of a green compact of powdered material with hard material particles, which are arranged at defined positions in the powdery material. The known method is based on three-dimensional data of the green body and has the following method steps:

^■ the green compact is divided into N, N> 2 successive cylindrical cross-sectional areas in a build-up direction, each cross-sectional area being formed from a two-dimensional cross-sectional area perpendicular to the body direction and a layer thickness parallel to the body direction,

■ On a build-up plane, which is arranged perpendicular to the mounting direction, N, N> 2 powder layers of the powdery material are applied and

»The hard material particles are arranged at the defined positions in the powdery material.

The hard material particles are picked up by means of a suction plate and positioned over the layer structure. By reducing the suction force or by a short burst of compressed air, the hard particles are released from the suction plate and placed in the upper powder layer of the layer structure. The blast of compressed air may only be so great that the pulp-shaped material is not displaced and the hard material particles are arranged at the intended defined positions of the distribution. Another disadvantage is that the hard material particles are arranged only loosely on or in the upper powder layer. When applying and distributing the next powder layer of the powdery material with the aid of an application tool in the form of a roller, a doctor blade or a brush, the hard material particles can be moved from the application tool from their defined positions and thus the accuracy can be reduced.

Presentation of the invention

The object of the present invention is to increase in the layered production of green compacts, which are compressed in particular to processing segments for abrasive processing tools, the accuracy with which the intended distribution of the insert elements is built in the green compact. In this case, the intended distribution of the insert elements in the green compact should also be maintained in the further layered production of the green compact. At the same time, the production costs for the accuracy and the Proportion of unwanted additional components, for example in the form of an adhesive or binder, be as low as possible in the green compact.

This object is achieved according to the invention in the aforementioned method for the layered production of a green compact of powdery material with defined arranged insert elements by the features of the independent claim 1. Advantageous developments are specified in the dependent claims.

The method for the layered production of a green compact of powdery material with insert elements, which are arranged at defined positions in the powdery material, according to the invention is characterized in that in the cross-sectional areas of the green body, which comprise the defined positions for the insert elements, set areas for the insert elements and prior to arranging the insert elements in the powdery material loose powder particles surrounding the setting areas, at least partially connected to each other. The bonded powder particles form support structures for the insert elements. The insert elements are placed in the support structures, which prevent the insert elements from being displaced when applying a further powder layer of the powdery material, so that the defined positions of the insert elements can be maintained with high accuracy during the layer construction.

Green compacts which are produced in layers by means of the method according to the invention consist of a plurality of successive cylindrical cross-sectional areas with a two-dimensional cross-sectional area perpendicular to the construction direction and a layer thickness parallel to the construction direction, wherein the cross-sectional areas are formed as a straight cylinder with an arbitrary cross-sectional area. The insert elements are arranged in a three-dimensional distribution in the green compact, wherein the positions of the insert elements are calculated with regard to a good cutting performance and are referred to as defined positions. For each insert element, a settling volume is provided in the green compact, in which the insert element is arranged. The setting volumes for the insert elements are like the green compact decomposed into successive areas, which are referred to below as setting areas. Depending on the height of the set volume, the set volumes can be composed of one setting area or of a plurality of setting areas which follow one another in the direction of construction. The number of successive setting areas depends on the layer thicknesses of the cross-sectional areas and the dimensions of the insert elements, in particular the height in the direction of construction.

The method according to the invention for the layer-by-layer production of a green compact is characterized in that support structures are produced before arranging the insert elements in the green compact. be witnesses that surround the setting areas for the insert elements in the construction level at least partially. The powdery material is when applying the powder layers of loose powder particles that do not form a connection with each other and can be moved against each other. The support structures for the insert elements are generated by connecting loose powder particles in the powdery material and they ensure that the insert elements can not be displaced when applying a further powder layer of the powdery material and can maintain their positions during layer construction. The fact that the powder particles of the powdery material are connected only to the setting areas, the proportion of unwanted Zusatzkom- components, for example in the form of an adhesive or binder, can be limited. Undesirable additional components in the green compact must be removed during a compression process by hot pressing and / or sintering. If the additional components can not be completely removed, the quality of the compacted component may suffer.

The support structures have a closed or non-closed cross-sectional shape and are, for example, annular or ring-shaped with a ring width and a ring height. The cross section of the ring shape or ring portion shape is formed, for example, as a circular ring or annulus section or as a multi-part ring or multi-part ring section. The ring or ring section shape is advantageously adapted to the geometry of the insert elements. The ring width and the ring height are designed so that the support structures are fixed in the powdery material. In many processes for the layered production of green compacts, the powdery material is applied by means of a tool in the form of a roll, a doctor blade or a brush, wherein the tool is moved in a feed direction over the layer structure. The tool is moved over the powdered material in a single feed motion or in a two-fold feed motion. In a one-time feed movement, it may be sufficient if the support ring is designed as a support wall on the opposite side, in a two-times feed movement (back and forth movement) support walls must be formed on opposite sides.

The method according to the invention for the layered production of a green compact is suitable for powdery materials, which are also referred to as material powders. The term "powdery materials" includes all materials that are solid in the initial state and consist of loose, ie not connected, powder particles. Powdered materials may consist of a material powder or be composed as a mixture of different material powders. The term "insert elements" encompasses all elements that can be integrated into one component. These include, inter alia, cutting elements, sensor elements, material fillings and Place retaining elements. The term "cutting element" summarizes all cutting means for abrasive machining segments. These include above all individual hard particles (particles of hard materials), composite parts made of several hard material particles and coated or encapsulated hard material particles. Hard materials are characterized by a special hardness. Hard materials can be subdivided into natural and synthetic hard materials and metallic and non-metallic hard materials. The natural hard materials include, among others, natural diamonds, corundum and other hard minerals and the synthetic hard materials include synthetic diamonds, high melting carbides, borides, nitrides and silicides. The metallic hard materials include, among others, the refractory carbides, borides, nitrides and silicides of the transition metals of the fourth to sixth group of the periodic table and the non-metallic hard materials include diamond, corundum, other hard minerals, silicon carbide and boron carbide.

Preferably, the loose powder particles surrounding the setting areas for the insert elements are connected together in a closed support structure. A support structure is referred to as closed when the support structure in the construction plane has a closed circumference and the setting area is completely surrounded by the support structure. The insert elements are placed in the closed support structure, which prevents the insert elements from being displaced when another powder layer of the powdered material is applied and the positions of the insert elements can be maintained with high accuracy during the layer construction. The formation of closed support structures lends itself to methods for the production of green compacts, in which the powdery material is applied with different feed directions. In addition, the stability of closed support structures is greater than support structures with an open perimeter. Alternatively, the loose powder particles surrounding the inserter seating areas are bonded together in a non-closed support structure. A support structure is said to be non-closed if the support structure has an open perimeter in the build-up plane and the set-up area is not completely surrounded by the support structure. The insert elements are placed in the non-closed support structure, which prevents the insert elements from being displaced when another layer of the powdery material is applied. In the case of non-closed support structures, the production costs involved in creating and the proportion of additional components compared to closed support structures are reduced.

In a particularly preferred embodiment, the non-closed support structure has a plurality of support sections, wherein the support sections are arranged around the insert elements. Several support sections surrounding the insert elements have the advantage that the insert elements are not displaced when applying a further powder layer of the powdery material and the positions of the insert elements can be maintained with a high accuracy during the layer construction. The use of a non-closed support structure reduces the manufacturing effort involved in creating and the proportion of additional components compared to closed support structures.

In an alternative particularly preferred embodiment, the non-closed support structure has at least one support section, wherein the support section is arranged on a side of the insert elements facing away from the application direction of the next powder layer. The use of non-closed support structures with a support section can further reduce the production effort involved in creating and the proportion of additional components. The support portion is placed so that the insert element is secured against displacement during application of the next powder layer from the support portion. For this purpose, the support section is arranged on the side of the insert elements, which faces away from the application direction of the next powder layer. Green compacts which are produced by the method according to the invention for the layered production are constructed in the construction direction from N, N> 2 cylindrical cross-sectional areas, which are composed of the cross-sectional area perpendicular to the construction direction and the layer thickness parallel to the construction direction. Each cross-sectional area comprises at least one outer cylindrical lateral surface, which is also referred to as outer lateral surface. For green bodies with internal recesses, the cross-sectional areas additionally comprise one or more inner cylindrical lateral surfaces, which are also referred to as inner circumferential surfaces. Boundary rings are defined for the outer and inner circumferential surfaces of the green body, the boundary rings of the outer jacket surfaces being referred to as outer boundary rings or outer rings and the boundary rings of the inner jacket surfaces as inner boundary rings or inner rings. The term "frontier ring" is used both

"outer boundary rings" as well as "inner boundary rings" summarized. The outer boundary rings have outer geometries that correspond to the outer circumferential surfaces of the cross-sectional areas, and the inner boundary rings have internal geometries corresponding to the inner circumferential surfaces of the cross-sectional areas. The layer thicknesses of the cross-sectional areas define the heights of the boundary rings.

In a first variant of the method, a base element with a base area that corresponds to the first cross-sectional area of the first cross-sectional area and a height that corresponds to the first layer thickness of the first cross-sectional area is defined for the first cross-sectional area and the loose powder particles of the powdered material become connected in the basic element. Green compacts which are produced in layers by means of the method according to the invention are, after the layer construction, subjected to a compaction process. process. For this purpose, the green compacts must be removed from the surrounding powdery material, without any powdery material emerging from the green compact. The bonded powder particles of the base form a floor for the green body and prevent leakage of the powdery material from the base. In a second variant of the method, for each cylindrical lateral surface of the first cross-sectional area, a first boundary ring having a geometry corresponding to the cylindrical lateral surface of the first cross-sectional area and a height corresponding to the first layer thickness of the first cross-sectional area is defined, the first powder layer of the powdered Material is applied to a substrate and the first boundary rings are connected to the substrate. When the green compact according to the second variant of the method is built up on a substrate, the substrate forms a floor for the green compact and prevents the powdery material from escaping. As a substrate, for example, serve thin metal plates.

Particularly preferably, the support structures are connected to the base element or to the substrate. With support structures which are connected to the base element or the substrate, the risk is reduced that the support structures are displaced by the application tool when applying a further powder layer of the powdery material.

For each cylindrical lateral surface of the second to Ν-1-th cross-sectional area, a second to Ν-1 boundary ring having a geometry corresponding to the cylindrical lateral surface of the second to Ν-1 cross-sectional area and a height corresponding to the layer thickness is preferred of the second to Ν-1-th cross-sectional area is defined. Green compacts which are produced in layers by means of the method according to the invention consist of several successive cylindrical cross-sectional areas with a cross-sectional area perpendicular to the construction direction and a layer thickness parallel to the construction direction. With the help of the second to Ν-1-th boundary rings of the powdery material of the green compact can be distinguished from the surrounding powdery material. Every second to Ν-1-th cross-sectional area has an outer cylindrical surface. For green bodies with internal recesses, the second to Ν-1-th cross-sectional areas additionally have one or more inner cylindrical lateral surfaces. For the outer surface and each inner surface of the green body, a second to Ν-1-th boundary ring is defined with a geometry and a height.

Particularly preferably, the loose powder particles of the second to Ν-1-th boundary rings are connected to each other and the second to Ν-1-th boundary rings are each connected to the underlying base element or the underlying first to Ν-2-th boundary rings. The boundary rings of the cross-sectional areas border the green area of the surrounding the powdered material. By connecting the superposed boundary rings a closed outer geometry can be generated.

In a first variant, for each cylindrical lateral surface of the Nth cross-sectional area, an N-th boundary ring having a geometry corresponding to the cylindrical lateral surface of the Nth cross-sectional area and a height corresponding to the Nth layer thickness of the Nth cross-sectional area , defined, the loose powder particles of the N-th boundary rings are connected together and the N-th boundary rings are connected to the underlying N-1-th marginal rings. With the help of the N-th boundary rings of the powdery material of the green compact can be distinguished from the surrounding powdery material. In order to prevent the powdery material from escaping from the green compact, the loose powder particles of the N-th boundary rings are joined together and the N-th boundary rings are connected to the Ν-1-th marginal rings below.

In a second variant, for the N-th cross-sectional area, a cover element having a top surface corresponding to the Nth cross-sectional area of the Nth cross-sectional area and a height corresponding to the Nth layer thickness of the Nth cross-sectional area is defined loose powder particles of the powdery material in the cover element are joined together and the cover element is connected to the underlying Ν-1-th boundary rings. When the green compact according to the second variant of the method is constructed, the Nth cross-sectional area forms a cover element for the green compact and prevents the powdery material from emerging. For this, the loose powder particles of the N-th cross-sectional area are connected to each other and the cover element is connected to the Ν-1-th marginal rings underneath. The second variant has the advantage that the green compact is closed on all sides, so that no powdery material can escape from the green compact. embodiments

Embodiments of the invention are described below with reference to the drawing. This is not necessarily to scale the embodiments, but the drawing, where appropriate for explanation, executed in a schematic and / or slightly distorted form. It should be noted that various modifications and changes may be made in the form and detail of an embodiment without departing from the general idea of the invention. The general idea of the invention is not limited to the exact form or detail of the preferred embodiment shown and described below or limited to an article which would be limited in comparison with the subject matter claimed in the claims. For given design ranges, also within the scope of the limits are disclosed as limit values and can be used arbitrarily and claimable. For simplicity, the same reference numerals are used below for identical or similar parts or parts with identical or similar function.

In the drawings: FIG. 1 shows a first green compact which is produced by means of the method according to the invention for layer-by-layer production from five cylindrical cross-sectional areas lying one above the other in a construction direction;

FIGS. 2A-E illustrate the five cross-sectional areas of the first green compact of FIG. 1, which consist of a two-dimensional cross-sectional area perpendicular to the construction direction and a layer thickness parallel to the construction direction;

FIGS. 3A, B show first and second cross sections through the first green compact of FIG. 1 parallel to the mounting direction along the cutting planes A-A in the FIGN. 2A-E (FIG 3A) and along the cutting planes B-B in the FIGN. 2A-E (FIG. 3B);

FIGS. 4A-L show the successive process steps of the method according to the invention for the layered production of the first green compact of FIG. 1 with defined arranged hard material particles;

FIGS. FIGS. 5A-E show five cylindrical cross-sectional areas of a second green compact which is built up on a substrate by means of the process according to the invention for the layer-by-layer production of a green compact; FIGS. 6A, B show a first and a second cross section through the second green compact in parallel with FIG

Assembly direction along the cutting planes A-A in the FIGN. 5A-E (FIG.6A) and along the cutting planes B-B in the FIGs. 5A-E (FIG.6B);

FIGS. FIGS. 7A-E show five cylindrical cross-sectional areas of a third green body called the

Cuboid having an internal recess is constructed by means of the method according to the invention for the layered production of a green compact;

FIGS. 8A, B show a first and a second cross section through the third green compact in parallel with FIG

Assembly direction along the cutting planes A-A in the FIGN. 7A-E (FIG.8A) and along the cutting planes B-B in the FIGs. 7A-E (FIG.8B); and

FIGS. 9A, B a first and second cross-sectional shape for support rings, the setting areas for a

Surround insert element. FIG. FIG. 1 shows a green compact 10 embodied as a cuboid, which is produced by means of the method according to the invention for the layered production of a green compact of powdered material with defined insert elements and is referred to below as the first green compact 0. The first green compact 0 is produced in a layer structure of five superimposed cylindrical cross-sectional regions 11, 12, 13, 14, 15, which are stacked on one another in a construction direction 16. The cylindrical cross-sectional areas 1 1 -15 have a layer thickness d "i = 1 to 5 parallel to the construction direction 16 and a cross-sectional area perpendicular to the construction direction 16. The layer thicknesses d 1, i = 1 to 5 may be uniform or the individual cross-sectional areas 11 -15 have different layer thicknesses.

In order to be able to produce the first green compact 10 in the layer structure, the cuboid 10 is disassembled in the construction direction 16 into the five cylindrical cross-sectional regions 11 -15 which are shown in FIGS. 2A-E are shown. In this case, FIG. 2A shows the first cross-sectional area 11, FIG. 2B, the second cross-sectional area 12, FIG. 2C, the third cross-sectional area 13, FIG. 2D shows the fourth cross-sectional area 14 and FIG. 2E the fifth cross-sectional area 15.

The first cross-sectional area 11 forms a base element 17 with a base area 18 that corresponds to the first cross-sectional area of the first cross-sectional area 11 and a first outer shell area 19. The second cross-sectional area 12 comprises a second outer ring 20 with a second outer circumferential area 21 and five second support rings 22, the second setting areas 23 surrounded. The third cross-sectional region 13 comprises a third outer ring 24 with a third outer circumferential surface 25 and nine third support rings 26 surrounding third setting regions 27. The fourth cross-sectional region 14 comprises a fourth outer ring 28 with a fourth outer circumferential surface 29 and four fourth support rings 30 surrounding the fourth setting regions 31. The fifth cross-sectional area 5 forms a cover element 32 with a cover surface 33, which corresponds to the fifth cross-sectional area of the fifth cross-sectional area 15, and a fifth outer lateral surface 34.

For distinction, the outer rings 20, 24, 28 referred to as i-th outer rings and the support rings 22, 26, 30 as i-th support rings. The outer rings 20, 24, 28 have an outer geometry, which corresponds to the outer circumferential surface 21, 26, 29 of the respective cross-sectional area 12, 13, 14, and a height, the layer thickness d ₂ , d ₃ , d _{4 of} the respective cross-sectional area 12, 13th , 14 corresponds to. The outer rings 20, 24, 28 are constructed in the form of a rectangular cylinder and delimit the first green compact 10 from the surrounding powdery material. In the exemplary embodiment, the setting areas 23, 27, 31 are square and surrounded by square support rings 22, 26, 30. Instead of the closed square support rings 22, 26, 30, other closed cross-sectional shapes or non-closed cross-sectional shapes may be used for the support rings. FIGS. 3A, B show first and second cross sections through the first green compact 10 of FIG. 1 parallel to the mounting direction 16 along the cutting planes AA in the figures. 2A-E (FIG 3A) and along the sectional planes BB in the figures. 2A-E (FIG. 3B). The five cylindrical cross-sectional areas 1 1 -15 of the first green body 10 are arranged one above the other in the construction direction 16.

During the layer construction of the first green body 10, a closed outer geometry is generated which prevents the escape of powdered material from the first green body 10. The closed outer geometry of the first green compact 10 is formed by the base element 17, the outer rings 20, 24, 28 and the cover element 32. With the aid of the outer rings 20, 24, 28, the powdery material of the first green compact 10 can be delimited from the surrounding powder-like material. The base member 17 is connected to the second outer ring 20, the second outer ring 20 is connected to the third outer ring 24, the third outer ring 24 is connected to the fourth outer ring 28 and the fourth outer ring 28 is connected to the cover member 32. In the second and third cross-sectional area 12, 13 five first support structures 35 are constructed and in the third and fourth cross-sectional area 13, 14 four second support structures 36 are constructed. The first support structures 35 are formed by the second support rings 19 and the overlying third support rings 22 and the second support structures 36 are formed by the fourth support rings 24 and the underlying third support rings 22. The first support structures 35 have a first deployment height and the second support structures 36 have a second deployment height h ₂ . FIG. 3A shows two first support structures 35 and a second support structure 36 and FIG. 3B shows a first support structure 35 and two second support structures 36.

In the exemplary embodiment of the first green body 10, the first and second support structures 35, 36 have the same cross-sectional shape and the same insertion height. Alternatively, the first support structures 35 may have a first cross-sectional shape and a first deployment height hi and the second support structures 36 may have a second cross-sectional shape and a second deployment height h ₂ , which are different from one another. Different cross-sectional shapes for the first and second support structures are suitable, for example, if different first and second insert elements are arranged in the support structures.

FIGS. 4A-L show the successive process steps of the method according to the invention for the layered production of the first green compact 10 of FIG. 1 of powdered material 41 with defined arranged insert elements 42. The first green compact 10 is in a subsequent compression process, for example by hot pressing and / or sintering to a machining segment for an abrasive machining tool compacted. The green compact 10 is produced from the powdery material 41 and insert elements in the form of cutting elements, which are formed as individual hard material particles 42. The hard material particles 42 originate from a mixture of hard material particles which are characterized by a minimum diameter D _min and a maximum diameter D _max , wherein 95% of the hard material particles are larger than the minimum diameter D _min and smaller than the maximum diameter D _max .

The first green compact 10 is produced in layers by means of a device comprising a build-up plane 43, a powder feeder and a print head. With the aid of the powder feed, a first powder layer 44 of the powdery material 41 having the first layer thickness di is applied (FIG. 4A). In the first cross-sectional area 11, the print head applies an adhesive layer which connects loose powder particles of the powdery material 41 to the base element 17, outside the base element 17 there are loose powder particles of the powdery material 41 (FIG. 4B).

With the aid of the powder feed, a second powder layer 45 of the powdered material 41 having the second layer thickness d _{2 is} applied (FIG. 4C). The print head applies adhesive in the region of the second outer ring 20 and the second support rings 22, which connects the loose powder particles of the powdery material 41 to the second outer ring 20 and the second support rings 22 (FIG. 4D). With the aid of the powder feed, a third powder layer 46 of the powdery material 41 with the third layer thickness d _{3 is} applied (FIG. 4E). The print head applies adhesive in the area of the third outer ring 24 and the third support rings 26, which connects loose powder particles of the powdery material 41 to the third outer ring 24 and the third support rings 26 (FIG. 4F).

The first deployment height hi of the first support structures 35 is achieved after the third cross-sectional area 13 has been finished, and the hard material particles 42 are arranged inside the first support structures 35 (FIG. 4G). In the exemplary embodiment, the first insertion height hi is greater than the maximum diameter D _{max of} the hard material particles 42. A first insertion height hi which is greater than the maximum diameter D _{max of} the hard material particles 42 has the advantage that the placed hard material particles 42 are almost completely within the first Support structures 35 are arranged and the risk that hard particles 42 are moved when applying a further powder layer is further reduced.

After the hard material particles 42 are arranged within the first support structures 35, the layer structure of the first green body 10 is continued. With the aid of the powder feed, a fourth powder layer 47 of the powdery material 41 having the fourth layer thickness d _{4 is} applied (FIG. 4H). In the region of the fourth outer ring 28 and the fourth support rings 30, the print head applies adhesive which contains loose powder particles of the pulverulent workpiece. Fabric 41 to the fourth outer ring 28 and the fourth support rings 30 connects (Figure 41). The second deployment height h _{2 of} the second support structures 36 is achieved after the fourth cross-sectional area 14 has been finished, and the hard material particles 42 are arranged inside the second support structures 36 (FIG. 4J). In the exemplary embodiment, the first application height n of the first support structures 35 and the second deployment height h _{2 of} the second support structures 36 coincide. Alternatively, the first and second application heights hi, h _{2 may be} different. The use of first and second support structures 35, 36 with different application heights, in which the same type of insert elements is arranged, is advantageous for green compacts, which are further processed into machining segments for abrasive machining tools. In the case of abrasive processing tools, insert elements must be exposed at the top of the processing segments, which process a substrate or a workpiece. For this purpose, the processing segments are usually sharpened until at the top insert elements are exposed. The sharpening of the machining segments can be omitted or at least reduced if the insert elements are arranged in the region of the upper side in support structures whose height is smaller than a minimum diameter of the insert elements. In the layer structure, a further powder layer is applied after the placement of the insert elements. The thickness of the powder layer can be used to determine if and how far the insert elements project at the top. After the hard material particles 42 are arranged within the second support structures 36, the layer structure of the first green body 10 is continued. With the aid of the powder feed, a fifth powder layer 48 of the powdery material 41 with the fifth layer thickness d _{5 is} applied (FIG. 4K). In the fifth cross-sectional area 15, the print head applies an adhesive layer which connects loose powder particles of the powdery material 41 to the cover element 32, and outside the cover element 32 there are loose powder particles of the powdery material 41 (FIG. 4L). FIG. 4M shows the first green compact 10 produced in layers from the pulverulent material 41 with a plurality of defined insert elements 42.

The first green compact 10 is produced in layers from five powder layers 44-48 with the same powdery material 41. Alternatively, the five powder layers 44-48 of the first green compact 10 may be made of different powdered materials 41. In the case of green compacts which are further processed into processing segments for abrasive processing tools, for example, a first pulverulent material can be used for the first powder layer 44 and a second pulverulent material for the further powder layers 45-48, the properties of the first pulverulent material being taken into account the connection of the processing segments with the main body and the properties of the second powdery material are selected with regard to the mechanical connection of the insert elements. When the machining segments are to be welded to the body, a weldable first powdered material is selected. FIGS. 5A-E show a further green compact 50, which is formed as a cuboid and is constructed with the aid of the method according to the invention for the layered production of a green compact of five superimposed cylindrical cross-sectional regions 51, 52, 53, 54, 55 in a construction direction 56. In this case, FIG. 5A, the first cross-sectional area 51, FIG. 5B shows the second cross-sectional area 52, FIG. 5C, the third cross-sectional area 53, FIG. 5D shows the fourth cross-sectional area 54 and FIG. 5E the fifth cross-sectional area 55.

The green compact 50 is produced from a pulverulent material 57 and insert elements in the form of cutting elements, which are designed in particular as individual hard material particles 42, the green compact 50 being referred to below as the second green compact 50. The insert elements 42 are arranged at defined positions in the second green compact 50, wherein the distribution of the insert elements 42 for the first and second green compacts 10, 50 match. While the first cross-sectional area 1 1 forms the base element 17 in the first green compact 10, the second green compact 50 is constructed on a substrate 58 as a base. The substrate 58 is, for example, a thin metal plate, which in a subsequent processing process is connected to the main body of an abrasive processing tool. The substrate 58 assumes the function of the basic element 17 of the first green body 10.

The first cross-sectional region 51 comprises a first outer ring 59 having a first outer circumferential surface 60 and first support rings 61 surrounding the first setting regions 62. The second cross-sectional region 52 comprises a second outer ring 63 with a second outer circumferential surface 64 and second support rings 65, which surround second setting regions 66. The third cross-sectional area 53 comprises a third outer ring 67 with a third outer circumferential surface 68 and third supporting rings 69, which surround third setting areas 70. The fourth cross-sectional area 54 comprises a fourth outer ring 71 with a fourth outer circumferential surface 72 and fourth support rings 73, which surround fourth setting areas 74. The fifth cross-sectional area 55 comprises a fifth outer ring 75 with a fifth outer circumferential surface 76.

The outer rings 59, 63, 67, 71, 75 of the cross-sectional areas 51-55 are constructed in the form of a rectangular cylinder and delimit the second green compact 50 from the surrounding powdery material 57. In the exemplary embodiment, the setting areas 62, 66, 70, 74 are square and surrounded by square support rings 61, 65, 69, 73. Instead of the closed square support rings 61, 65, 69, 73, other closed transverse sectional forms or non-closed cross-sectional shapes for the support rings 61, 65, 69, 73 are used.

FIGS. FIGS. 6A, B show first and second cross sections through the second green compact 50 parallel to the mounting direction 56 along the sectional planes A-A in the FIGS. 5A-E (FIG.6A) and along the cutting planes B-B in the FIGs. 5A-E (FIG.6B). The five cylindrical cross-sectional areas 51 - 55 of the second green body 50 are arranged one above the other in the construction direction 56.

In the layer structure of the second green body 50, an outer geometry is generated which prevents the escape of powdery material 57 from the second green body 50. The outer geometry of the second green compact 50 is formed by the substrate 58 and the outer rings 59, 63, 67, 71, 75. The substrate 58 is connected to the first outer ring 59, the first outer ring 59 is connected to the second outer ring 63, the second outer ring 63 is connected to the third outer ring 67, the third outer ring 67 is connected to the fourth outer ring 71 and the fourth outer ring 71 is connected to the fifth outer ring 75.

The outer geometry of the second green compact 50 is designed to be open at the top in the fifth cross-sectional area 55, so that the second green body 50 has to be transported upright for a subsequent compacting process. In order to delimit the second green compact 50 also in the fifth cross-sectional area 55 to the outside, the fifth cross-sectional area 55 may alternatively form a cover element, which is connected to the fourth outer ring 71. For this purpose, the print head in the fifth cross-sectional area 55 carries an adhesive layer which connects the loose powder particles of the powdery material 57 to the cover element.

The second green compact 50 has five first support structures 77 and four second support structures 78. The first support structures 77 are constructed by the first, second and third setting regions 62, 66, 70 and have a first insertion height hi. The second support structures 78 are constructed by the first, second, third and fourth setting areas 62, 66, 70, 74 and have a second insertion height h ₂ . The first and second support structures 77, 78 are connected to the substrate 58 and thereby securely fixed in the second green compact 50.

To construct the first support structures 77, the first support rings 61 are connected to the substrate 58, the second support rings 65 are connected to the first support rings 61 and the third support rings 69 are connected to the second support rings 65. To construct the second support structures 78, the first support rings 61 are connected to the substrate 58, the second support rings 65 are connected to the first support rings 61, the third Support rings 69 are connected to the second support rings 65 and the fourth support rings 73 are connected to the third support rings 69.

FIGS. 7A-E show a further green compact 80, which is formed as a cuboid with an internal recess and with the aid of the method according to the invention for the layerwise production of a green compact of five superposed cylindrical cross-sectional areas 81, 82, 83, 84, 85 in a construction direction 86 is constructed of a powdery material 87. In this case, FIG. 7A shows the first cross-sectional area 81, FIG. 7B shows the second cross-sectional area 82, FIG. 7C, the third cross-sectional area 83, FIG. 7D illustrates the fourth cross-sectional area 84 and FIG. 7E, the fifth cross-sectional area 85. The green compact 80 is referred to below as the third green compact 80, which extends from the first green compact 10 of FIG. 1 differs in that the third green compact 80 has a continuous internal recess 88 and eight insert elements 42, which are arranged at defined positions in the third green compact 80. For the insert elements 42 80 set areas are defined in the cross-sectional areas 81-85 of the third green compact, which are surrounded by support rings.

The first cross-sectional area 81 forms a base element 89 with a base area 90 that corresponds to the first cross-sectional area of the first cross-sectional area 81 and a height that corresponds to the first layer thickness d _{1 of} the first cross-sectional area 81. The base element 89 has a first outer lateral surface 91 in the form of a rectangular cylinder and a first inner lateral surface 92 in the form of a circular cylinder.

The second cross-sectional area 81 comprises a second outer ring 93 with a second outer circumferential surface 94, a second inner ring 95 with a second inner lateral surface 96 and four second supporting rings 97 surrounding the second setting regions 98. The third cross-sectional area 83 comprises a third outer ring 99 with a third outer circumferential surface 100, a third inner ring 101 with a third inner lateral surface 102, and eight third supporting rings 103 surrounding the third setting regions 104. The fourth cross-sectional area 84 comprises a fourth outer ring 105 with a fourth outer circumferential surface 106, a fourth inner ring 107 with a fourth inner lateral surface 108 and four fourth support rings 109 surrounding the fourth setting regions 110. The fifth cross-sectional area 85 forms a cover element 111 with a cover surface 112 that corresponds to the fifth cross-sectional area of the fifth cross-sectional area 85 and a height that corresponds to the fifth layer thickness d _{5 of} the fifth cross-sectional area 85. The cover element 1 1 1 has a fifth outer lateral surface 113 in the form of a rectangular cylinder and a fifth inner lateral surface 114 in the form of a circular cylinder. FIGS. 8A, B show a first and second cross section through the third green compact 80 in parallel to the mounting direction 86 along the sectional lines AA in the figures. 7A-E (FIG.8A) and along the cutting planes BB in the FIGs. 7A-E (FIG.8B). The five cross-sectional areas 81-85 of the third green compact 80 are arranged one above the other in the direction of construction 86. In the layer construction of the third green compact 80, a closed outer geometry is produced which prevents the escape of powdered material 87 from the third green compact 80. The closed outer geometry of the third green compact 80 is formed by the base element 89, the outer rings 93, 99, 105, the inner rings 95, 101, 107 and the cover element 1 1 1. The outer rings 93, 99, 105 are also referred to as outer boundary rings and the inner rings 95, 101, 107 as inner boundary rings, wherein the outer and inner boundary rings are summarized by the term "boundary rings". The base element 89 is connected to the second boundary rings 93, 95, the second boundary rings 93, 95 are connected to the third boundary rings 99, 101, the third boundary rings 99, 101 are connected to the fourth boundary rings 105, 107 and the fourth boundary rings 105, 107 are connected to the cover element 1 1 1.

The third green compact 80 has four first support structures 115 and four second support structures 116. The first support structures 15 are formed by the second and third setting areas 98, 104 and have a first insertion height hi. The second support structures 1 6 are formed by the third and fourth setting areas 104, 110 and have a second insertion height h ₂ . FIG. 8A shows two first support structures 1 15 and a second support structure 1 16 and FIG. 8B shows two second support structures 16 and the recess 88.

The first support structures 15 are connected to the base element 89 and the second support structures 16 are not connected to the base element 89. The first support structures 1 15 are fixed by the connection with the base member 89 in the third green compact 80 and are not displaced when applying a further powder layer. The second insertion height h _{2 of} the second support structures 1 16 is adapted exclusively to the dimensions of the insert elements 42. If the second support structures 16 are adequately secured in the powdery material 87 and are not displaced when another powder layer is applied, this variant has the advantage that the proportion of adhesive or binder in the third green body 80 is reduced. In the event that the second support structures 1 16 are not sufficiently secured in the powdery material 87, the second support structures 1 16 can be connected to the base member 89. For this purpose, 81 further first support rings are constructed in the first cross-sectional area, which are connected to the base member 89 and the second support rings of the second support structures 1 16. FIGS. FIGS. 9A, B show first and second cross-sectional shapes for support rings 121, 122 surrounding set-up areas for an insert element 123. The support rings 121, 122 may surround the seating areas 23, 27, 31 of the first green body 10, the seating areas 62, 66, 70, 74 of the second green body 50, and / or the seating areas 98, 104, 110 of the third green body 80. The support rings 121, 122 replace the support rings 22, 26, 30 of the first green body 10, the support rings 61, 65, 69, 73 of the second green body 50 and / or the support rings 97, 103, 109 of the third green body 80 and form the first and second support structures 35, 36, 77, 78, 115, 16.

FIG. FIG. 9A shows the support ring 121, which forms a non-closed support structure for the insert 123. The support ring 121 consists of a plurality of support portions 124A, 124B, 124C, 124D surrounding the insert member 123 and preventing displacement of the insert member 123.

FIG. FIG. 9B shows the support ring 122 which forms a non-closed support structure for the insert element 123. The support ring 122 consists of a support section 125 against which the insert element 123 abuts. The support portion 125 is placed so that the insert member 123 is secured against displacement when the next powder layer is applied by the support portion 125. For this purpose, the support section 125 is arranged on the side of the insert elements 123, which faces away from the application direction 126 of the next powder layer.

Claims

claims

1 . Process for the layered production of a green body (10; 50; 80) of powdery material (41; 57; 87) with insert elements (42; 123) arranged at defined positions in the powdery material (41; 57; 87), based on three-dimensional data of the green body (10, 50, 80), with the following procedural steps:

^■ the green compact (10; 50; 80) in a build direction (16; 56; 86) in N, N> 2 consecutive cylindrical cross-sectional areas (1 1, 12, 13, 14, 15; 51, 52, 53, 54, 55; 81, 82, 83, 84, 85), each cross-sectional area (11-15; 51-55; 81-85) being formed from a two-dimensional cross-sectional area perpendicular to the construction direction (16; 56; 86) and a layer thickness (i.e. , d ₂ , d ₃ , d ₄ , d ₅ ) parallel to the mounting direction (16;

56; 86) is formed,

^■ N, N> 2 powder layers (44, 45, 46, 47, 48) of the powdery material (41, 57, 87) are applied to a construction plane (43) perpendicular to the assembly direction (16, 56;

The insert elements (42, 123) are arranged at the defined positions in the pulverulent material (41, 57, 87),

characterized in that in the cross-sectional areas (12, 13, 14; 52, 53, 54; 82, 83, 84) of the green body (10; 50; 80) comprising the defined positions for the insert elements (42; 123), Setting areas (23, 27, 31, 62, 66, 70, 74, 98, 104, 110) for the insert elements (42, 123) and before arranging the insert elements (42) in the powdery material (41). loose powder particles surrounding the setting areas (23, 27, 31, 62, 66, 70, 74, 98, 104, 110) are at least partially interconnected.

2. The method according to claim 1, characterized in that the loose powder particles surrounding the setting areas (23, 27, 31, 62, 66, 70, 74, 98, 104, 110) for the insert elements (42) in one closed support structure (35, 36; 77, 78, 1 15, 1 16) are interconnected.

3. The method according to claim 1, characterized in that the loose powder particles surrounding the setting areas (23, 27, 31, 62, 66, 70, 74, 98, 104, 110) for the insert elements (123) in one non-closed support structure (35, 36; 77, 78; 1 15, 16) are connected to one another.

4. The method according to claim 3, characterized in that the non-closed

Support structure (35, 36; 77, 78, 1 15, 1 16) a plurality of support portions (124 A, 124 B, 124 C, 124 D), wherein the support portions (124 A, 124 B, 124 C, 124 D) are arranged around the insert elements (123).

5. The method according to claim 3, characterized in that the non-closed support structure (35, 36; 77, 78; 1 15, 16) has at least one support section (125), wherein the support section (125) in one of the application direction ( 126) of the next powder layer facing away from the insert elements (123) is arranged.

6. Method according to one of claims 1 to 5, characterized in that, for the first cross-sectional area (1 1, 81), a base element (17, 89) having a base area (18, 90) corresponding to the first cross-sectional area of the first cross-sectional area (1 1, 81) and a height corresponding to the first layer thickness (di) of the first cross-sectional area (11; 81) and the loose powder particles of the powdered material (41; 87) in the base element (17; ).

7. The method according to any one of claims 1 to 5, characterized in that for each cylindrical lateral surface (60) of the first cross-sectional area (51) a first boundary ring (59) having a geometry of the cylindrical lateral surface (60) of the first cross-sectional area (51 ), and a height corresponding to the first layer thickness (di) of the first cross-sectional area (51), the first powder layer (44) of the powdery material (41) is applied to a substrate (58) and the first Boundary rings (59) are connected to the substrate (58).

8. The method according to any one of claims 6 to 7, characterized in that the support structures (35; 77, 78; 1 15) with the base member (17; 89) or with the substrate (58) are connected.

9. The method according to any one of claims 6 to 7, characterized in that for each cylindrical lateral surface (21, 26, 29; 63, 67, 71; 94, 96, 100, 102, 106, 108) of the second to Ν-1 a second to N-1 boundary ring (20, 24, 28, 63, 67, 71, 93, 95, 99, 32, 83, 84, 52, 83, 84, 52, 53, 54, 82, 83, 84). 101, 105, 107) having a geometry which corresponds to the cylindrical lateral surface (21, 26, 29; 63, 67, 71; 94, 96, 100, 102, 106, 108) of the second to Ν-1th cross-sectional area (12 , 13, 14, 52, 53, 54, 82, 83, 84), and a height corresponding to the layer thickness (d ₂ , d ₃ , d ₄ ) of the second to Ν-1-th cross-sectional area (12, 13, 14, 52, 53, 54, 82, 83, 84) is defined.

10. The method according to claim 9, characterized in that the loose powder particles of the second to Ν-1-th boundary rings (20, 24, 28, 63, 67, 71, 93, 95, 99, 101, 105, 107) connected to each other and the second to Ν-1-th boundary rings (20, 24, 28, 63, 67, 71, 93, 95, 99, 101, 105, 107) are respectively connected to the underlying base member (17, 89) or below lying first to Ν-2-th boundary rings (20, 24, 59, 63, 67, 93, 95, 99, 101) are connected.

1 1. A method according to claim 10, characterized in that for each cylindrical lateral surface (76) of the N-th cross-sectional area (55) an N-th boundary ring (75) having a geometry of the cylindrical lateral surface (76) of the N-th cross-sectional area (55 ), and a height corresponding to the N-th layer thickness (d ₅ ) of the N-th cross-sectional area (55), the loose powder particles of the N-th boundary rings (75) are connected to each other and the N- Boundary rings (75) are connected to the underlying Ν-1-th boundary rings (71).

12. The method according to claim 10, characterized in that for the N-th cross-sectional area (15; 85) a cover element (32; 1 1 1) having a cover surface (33; 1 12), which corresponds to the Nth cross-sectional area of the N and a height corresponding to the N-th layer thickness (d ₅ ) of the N-th cross-sectional area (15; 85), the loose powder particles of the powdery material (41; Cover element (32, 1 1 1) are interconnected and the cover element (32, 1 1 1) with the underlying Ν-1-th boundary rings (23, 105, 107) is connected.