DE102007058976A1 - Process to fabricate a metal form component by laser build-up of low carbon metal powder lasers - Google Patents

Abstract

In a process to fabricate a metal component, a layer of metal powder is molten by a high-energy laser beam, followed by application of second and subsequent layers similarly treated. The metal is a low-alloy iron-based material in which the carbon content does not significantly exceed 0.15 % Wt.

Description

The The invention relates to a method for producing a shaped body by layered build up of powdered, metallic Material in which successively applied several layers one above the other with each powder layer before applying the following Layer with a high energy beam in a given area over their entire layer thickness completely melted becomes.

Such a method, which is also known as selective laser (jet) melting, is out DE 196 49 865 C1 known. In the method disclosed therein, a metallic material powder, which is present as binder-free and flux-free metallic material powder, distributed on a support surface to form a powder bed. A guided by a computer control laser beam is passed over those areas of the powder bed, which represent the cross section of the molded part to be manufactured. In this case, the metallic material powder is heated by the laser beam to melting temperature, wherein the energy of the laser beam is selected so that the metallic material powder is completely melted at the point of impact of the laser beam over its layer thickness, so that after solidification of the material formed a continuous layer of solid material becomes. After working the first powder layer on this first layer, a second layer of the metallic material powder is distributed. This is in turn partially melted by means of the laser beam, wherein a fusion-technical connection between the two layers is produced by a melting of the previously cured areas of the first layer. By repeating these process steps, the desired molded part geometry is built up in layers.

The Selective laser (jet) melting differs from the process of selective laser sintering in particular in that the latter process, the metallic material powder used not completely melted; rather, it becomes one used two-component metal powder, which consists of a refractory and a low melting component. The laser beam melts the low melting point component used as the binding material for the refractory component is used. It therefore creates a metallic matrix, wherein the particles of the refractory component and the low-melting component in a diffusion process be connected to each other.

Of the significant advantage of selective laser (jet) melting opposite the selective laser sintering is that generative components are produced which are cast in their strength and density Approximate shape match. In contrast, will produced during selective laser sintering a molding, which consists of a is relatively porous material and that due to the only "sticky" connection of the individual particles with each other only has a low strength. In particular from this Reason is the selective laser sintering almost exclusively manufactured for the production of prototypes that do not require high mechanical Be exposed to stress.

So far, with the from the DE 196 49 865 C1 known processes only processed high-alloyed metallic materials.

Specifically reveals the DE 196 49 865 C1 the processing of material powders made of stainless steel, aluminum or titanium. Due to the high material costs of these materials, the production of molded parts by means of in the DE 196 49 865 C1 However, disclosed method associated with high costs.

outgoing From this prior art, the invention is therefore the task underlying the cost of producing a molded part by means of the generative manufacturing process known as jet melting to lower.

These The object is achieved by the subject matter of the independent patent claim solved. Advantageous embodiments are the subject the dependent claims.

Of the Core of the invention provides, in a method of the aforementioned Art, in which for producing a shaped body by a layered build up of powdered, metallic material successively applied several layers one above the other with each powder layer before applying the following Powder layer with a high energy beam in a given range over the entire layer thickness is completely melted, to process a ferrous material, the carbon content of a Value of 0.15 wt .-% does not significantly exceed. By the use of such an iron material as a base material for the generic beam melting can the material costs and, consequently, the production costs for the moldings are lowered decisively. By the invention Restriction of the carbon content can, however, a sufficient Processability of the material ensured in a beam melting process become.

A proportion of the carbon of not more than 0.03% by weight and in particular of 0.015% by weight has proven to be particularly advantageous in this respect issued.

When High energy beam may preferably be a laser beam used come, however, whereby any kinds of high-energy beams, such as For example, electron beams can be used.

Um - ever according to purpose - even with inventive Ferrous materials as base material sufficient mechanical characteristics, such as z. B. strength to receive, can in a preferred Be provided embodiment, the iron material with at least one second material, preferably also as Powder may be present, to mix. Such a filler material can for example, to a nucleation during be used of the beam melting process. The mixing can become one any time during the process; especially the ferrous material can already with the second before melting Material are mixed. Likewise, an admixture in the molten Iron material possible. The second material can also agglomerated on the iron material. This way you can Dismantling of the powder prevents the formation of the molten bath become.

The second powder may advantageously be based on technical Ceramics (eg silicon oxide, carbide) and / or other silicon compounds, Diamond, niobium and / or boron (especially to adjust the toughness, Strength and through-hardenability of the component). By the targeted fusion of the ferrous material and the second material can specifically target material properties as well as structural and surface structures changed or be produced by the material of the second powder in the form of crystallization seeds in the low-alloy ferrous material is introduced.

at However, the second or the further materials can also be to act a metallic material, such as steel powder. In In this case, the material properties of the produced Formkör pers example by defined mixing and / or Size ratios of materials influenced become.

For For example, a variation of a powder composition the (different) magnetic properties of the individual components be exploited. By a corresponding application of a magnetic Felds can target the different magnetic materials mixed or demixed.

to Production of a powder mixture of the materials can continue First, the second powder is dissolved, that is be distributed in a gas stream to then in a second Atomization process to be mixed with the iron material. In this way, a particularly homogeneous mixing of the powder be achieved.

QUOTES INCLUDE IN THE DESCRIPTION

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Cited patent literature

• - DE 19649865 C1 [0002, 0005, 0006, 0006]

Claims (6)

A process for the production of a shaped article by layering of powdered metallic material, wherein successively several layers are applied one above the other, wherein each powder layer is melted before applying the subsequent powder layer with a high energy beam in a predetermined range over the entire layer thickness, characterized in that an iron material with a share of max. 0.15 wt .-% carbon is processed. Process according to claim 1, characterized characterized in that a ferrous material with a share of max. 0.03 wt .-% and in particular of 0.015 wt .-% carbon processed becomes A method according to claim 1 or 2, characterized in that the iron material with a second Powder is mixed. A method according to claim 3, characterized characterized in that the second powder based on diamond, niobium, Boron and / or a silicon compound is. A method according to claim 4, characterized characterized in that the second powder is a metallic powder. A method according to claim 4 or 5, characterized in that the second powder initially atomized and in a second atomization process with the iron material is mixed.