WO2018069411A1

WO2018069411A1 - Method for producing an object by means of laser melting

Info

Publication number: WO2018069411A1
Application number: PCT/EP2017/075970
Authority: WO
Inventors: Marcus Abele; Andreas Rehl
Original assignee: Mahle International Gmbh
Priority date: 2016-10-14
Filing date: 2017-10-11
Publication date: 2018-04-19
Also published as: DE102016220136A1

Abstract

The present invention relates to a method for producing an object (6) by means of laser melting. It is essential to the invention that at least two different powdery starting materials (4, 5) are used, which have different strength properties and heat conduction properties, that the at least two different starting materials (4, 5) are arranged in the object (6) that is to be built up by laser melting in such a manner that said object has predefined local strength properties and heat conduction properties.

Description

Method for producing an object by means of laser melting

The present invention relates to a method for producing a

Subject by Selective Laser Melting (SLM for Selective Laser Melting) according to the preamble of claim 1. The invention also relates to a piston produced by this method and to a mold or die produced by this method.

From DE 10 2015 209 702 A1 a generic method for

Production of an article by direct metal laser sintering (DMLS) known here for the production of a casting tool, wherein at least a portion of the casting tool to be produced has a plurality of smaller openings, in particular microbores, for air removal, to air pockets of im

Gravity chill casting pistons for internal combustion engines to avoid. The objects produced by means of the known method have a homogeneous structure.

Selective laser sintering (SLS) is a process for producing spatial structures by sintering from a powdery starting material. Laser sintering is a generative layer construction process in which the article to be produced is built up layer by layer. As a result of the melting effect of the laser beams used, any desired three-dimensional geometries can also be produced with undercuts, that is to say objects and workpieces which can not be produced in conventional mechanical or casting-technical production. Laser sintering is used in particular for producing prototypes and small numbers of complicated components. In the case of the known laser sintering method, a powder-form starting material is used which subsequently produces the material of the produced material Object forms. This can be for example a plastic, but also a metal. While the laser sintering is carried out below the melting temperature of the powder or its main component and the compounds are prepared by diffusion to form sintered necks, the powder mixture is locally liquefied during laser melting, whereby a workpiece similar to a casting can be produced. Its material has homogeneous properties, but this is especially uneven

loaded objects or components is not necessarily beneficial

The present invention therefore deals with the problem for a

Method of the generic type to provide an improved or at least one alternative embodiment, which in particular overcomes the disadvantages known from the prior art.

This problem is solved according to the invention by the subject matter of independent claim 1. Advantageous embodiments are the subject of the dependent claims.

The present invention is based on the general idea of using for the first time in a laser melting to produce an article at least two different powdery starting materials, the

have different strength properties and heat conduction properties and thus produce an article that has in particular locally predefined strength properties and thermal conductivities. This is for example possible because the at least two different starting materials are arranged in the object to be built up by laser melting at a defined location and melted there, so that, for example, objects with locally increased heat conductivities or locally increased strengths are relatively easy to produce. in the Compared to the methods known from the prior art, which exclusively used a single powdery starting material, an inhomogeneous structure of an article can thus be easily achieved, taking into account in particular individual local heat conduction requirements or strength requirements. By using two or more different powder alloys, it is thus possible for the first time, the object, for example a piston, a die or a mold for a piston, with locally different thermal conductivities and

Equip heat capacity, whereby the object can be cooled, for example, during casting or forging directed and thus both higher rates of application, higher qualities and possibly also thinner wall thicknesses can be achieved. In particular, in the case of an object designed as a piston, this can be optimized with respect to its profile of requirements in terms of temperature, deformation and fatigue strength.

In an advantageous development of the solution according to the invention, an iron-based powder or an iron-based material is used as the starting material

Powder alloy, in particular powdered X3NiCoMoTi 18-9-5 used. The last-mentioned alloy is a high-strength and high-strength, martensitic-hardening nickel steel with a simple heat treatment, which can be used in particular for casting molds. Due to the high strength, it can of course be used for articles that require such high strength.

In a further advantageous embodiment of the solution according to the invention, a copper-based powder is used as the starting material. By using a copper-based powder as a starting material, a starting material can be achieved with a significantly increased thermal conductivity, which is particularly advantageous if in one by means of According to the laser melting process of the invention locally increased thermal conductivities are desired in order to achieve, for example, a faster heat dissipation can.

The present invention is further based on the general idea of a piston having the method described in the previous paragraphs

and thereby to be able to produce a piston which is inhomogeneous in terms of its strength properties and in terms of its heat conduction properties. For example, it may be provided that the piston in the region of a piston head, a piston recess, a ring portion and / or a cooling channel has a copper-based starting material or in these areas from the copper-based starting material means

Laser melting is made and therefore there has an increased thermal conductivity. In particular, a faster heat dissipation and thus better cooling of the piston can be achieved by means of this increased thermal conductivity, as a result of which both its service life and its performance can be increased.

In an advantageous development of the solution according to the invention, the piston is produced in the region of a piston skirt, a box wall and / or a hub made of an iron-based starting material by means of laser melting and thus has increased strength properties there. An iron-based starting material used for this purpose can be, for example, X3NiCoMoTi 18-9-5. This makes it possible, for example, a mechanically heavily loaded in operation region of the piston, such as the piston skirt or the hub, form of a higher-strength material, while in the region of the cooling channel, for example, a heat-removing copper-based starting material is used. By means of the method according to the invention it is thus possible to use a piston with respect to its locally occurring To calculate loads, both in mechanical and in thermal terms and to take into account these individual load situations with introduction of different starting materials. It is

Of course, it is clear that in the process according to the invention not only two different pulverulent starting materials can be used, but also three or more, in order thereby to influence in an even more varied manner influence on individual and in particular locally limited

To take properties.

The present invention is further based on the general idea of producing a casting mold or a die for a piston by means of the method described above, whereby for the first time not only a single-material tool made of steel has to be manufactured in a machining process, but additive from different, powdery starting materials can be built. This makes it possible in particular to incorporate a copper-based starting material in those areas of the die or the casting mold by means of laser melting, in which later a directed and improved heat dissipation, that is cooling of the die or the casting mold is to be achieved. Due to this individual possibility of locally improved cooling of the mold or the die, higher

Output rates, a higher quality and, where appropriate, thinner wall thicknesses are achieved, whereby both cost and high quality production of pistons is possible. Of course, the casting mold or the die can also be designed in several parts, wherein at least one component in the casting mold or the die is made of additive-generated and interconnected by means of laser melting

Powder mixtures may exist, which defined geometrically, that can be arranged at exactly predefined location and place in the mold in the die. Other important features and advantages of the invention will become apparent from the dependent claims, from the drawings and from the associated

Description of the figures with reference to the drawings.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the particular combination given, but also in other combinations or in isolation, without departing from the scope of the present invention.

Preferred embodiments of the invention are illustrated in the drawings and will be described in more detail in the following description, wherein like reference numerals refer to the same or similar or functionally identical components.

Show, each schematically

Fig. 1 is a manufactured by a method according to the invention

Casting tool or casting mold and / or piston,

Fig. 2 is a partially sectioned view of one by means of

inventive method produced piston.

Corresponding to FIG. 1, a casting tool 1 is shown, whose casting molds 2 are produced by means of a laser melting process according to the invention.

Also shown in FIG. 1 and additionally in FIG. 2 is a piston 3, which was also produced by means of the laser melting process according to the invention. The piston 3 is shown in Figure 1 only for the sake of clarity in the casting tool 1, it being understood that the inventive piston 3 produced by laser melting is not poured into the casting tool 1.

According to the invention, the casting molds 2 or the means of the

According to the laser melting process according to the invention produced piston 3 at least two different starting materials 4, 5, the different

Have strength properties and heat conduction properties. The at least two different starting materials 4, 5 are in the means of

Laser melt to be built object 6, for example, as a casting mold 2, as a piston 3 or as a die for forging pistons

may be formed, arranged such that the article 6 has predefined local strength properties and heat conduction properties.

In the method according to the invention for producing the article 6 by means of laser melting, at least two, preferably also more, different powdery starting materials 4, 5 are used for the first time, which have different strength properties and thermal conduction properties and which are furthermore arranged in the object 6 to be built up by means of laser melting. in localized areas, this has predefined local strength properties and thermal conduction properties, in particular higher strengths or higher thermal conductivities.

In general, the different starting materials 4, 5 are referred to in the figures, it being understood that it is clear that they have different materials 4, 5 with different colors after the laser melting

Give strength properties and different heat conduction properties. With the reference numerals 4, 5 are thus both the starting materials and the materials in the later by means of the invention

Laser melt process manufactured article 6 referred to. As the starting material 5, for example, an iron-based powder, in particular powdery X3NiCoMoTi 18-9-5, can be used, that is, a steel alloy with comparatively high toughness and comparatively high strength. In the subject invention 6 this is

Starting material 5 arranged or used in areas in which an increased strength is desired. In contrast, the starting material 4, which is formed for example as a copper-based powder, used in areas in which an increased thermal conductivity is required.

If, for example, FIGS. 1 and 2 are considered, it can be seen that a piston 3 has been produced in the region of a piston head 7 of a combustion bowl 8, a ring section 9 and / or a cooling channel 10 made of a copper-based starting material 4 is formed and therefore there has improved thermal conduction properties, which in particular allow better cooling of the piston 3 according to the invention. In contrast, the piston 3 in the region of a piston stem, a hub 1 1 or a box wall on an iron-based starting material 5, for example X3NiCoMoTi 18-9-5, whereby the piston 3 in those areas in which an increased strength is required, with the

Starting material 5 and the material 5 is formed, which meets these increased strength requirements.

With the method according to the invention, virtually any three-dimensional objects 6 can thus be built up by means of laser melting, with only a single pulverulent one being used in comparison with previous ones

Starting material using laser melting process now in the

Subject local areas with different Strength properties and different heat conduction properties can be produced.

In the same way, of course, casting molds 2 or dies for forging pistons according to the invention

Laser melting of several starting materials 4, 5, at least made of two different starting materials 4, 5 and thereby optimally adapted to individual and site-specific strength or thermal requirements. It is of course clear that the copper-based starting material 4 does not necessarily have to be led to the surface of the article 6, but also covered by a layer of the iron-based base material 5 and thus can be arranged protected.

Claims

claims

1 . Method for producing an object (6) by means of laser melting, characterized

- that at least two different powdery

Starting materials (4,5) are used, which have different strength properties and heat conduction properties,

- That the at least two different starting materials (4,5) are arranged in the object to be built up by means of laser melting (6) such that this predefined local

Has strength properties and heat conduction properties.

2. The method according to claim 1,

characterized,

that as starting material (5) an iron-based powder, in particular powdery X3NiCoMoTi 18-9-5, is used.

3. The method according to claim 1 or 2,

characterized,

that as starting material (4) a copper-based powder is used.

4. The method according to any one of claims 1 to 3,

characterized,

in that a piston (3), a casting mold (2) for a piston or a die is produced by means of the method.

5. Piston (3), produced by the method according to one of claims 1 to 3.

6. Piston according to claim 5,

characterized,

that the piston (3) in the region of a piston head (7), a

Combustor cavity (8), a ring portion (9) and / or a cooling channel (10) has a copper-based starting material (4).

7. Piston according to claim 5 or 6,

characterized,

the piston (3) has an iron-based starting material (5) in the region of a piston skirt, a box wall or a hub (11), in particular X3NiCoMoTi18-9-5.

8. Piston according to one of claims 5 to 7,

characterized,

the piston (3) has a copper-based region

Starting material (4), that of an iron-based

Starting material (5), in particular X3NiCoMoTi 18-9-5, is covered.

9. mold (2) or die for a piston manufactured according to the

Method according to one of claims 1 to 3.