This application is a National Stage of International Application No. PCT/EP2019/065751 filed Jun. 14, 2019, claiming priority based on French Patent Application No. 18 55287 filed Jun. 15, 2018, the entire contents of each of which are herein incorporated by reference in their entireties.
The invention relates to a method of making a part with a cavity by additive manufacturing.
Additive manufacturing methods (of the electron beam melting or the selective laser melting type) for making a part consist in progressively solidifying a powder material in layers that build up in a buildup direction (or manufacturing direction), and the use of additive manufacturing for making a part with a cavity suffers from limitations concerning acceptable overhang angles. Under such circumstances, a cavity of large size needs to have a ceiling that is vaulted in order to comply with such overhang angle constraints, thereby increasing both the internal and the external volume of the cavity. Nevertheless, certain parts have constraints in terms of volume and size, and it is not possible to envisage such a cavity with a ceiling that is vaulted. In order to make a cavity with a ceiling that, although not flat, is vaulted little, additive manufacturing software very often includes a function enabling supports in the shape of columns to be created while manufacturing the part in order to support the ceiling of the cavity while it is being manufactured. Nevertheless, the columns occupy a considerable volume, and for cavities that are semi-closed, or that are open to the outside solely via a fluid inlet channel, it is not possible to eliminate such columns.
The invention seeks to provide a method of making a part with a cavity by additive manufacturing, the method serving to minimize the volume occupied by the supports that support the ceiling and that are to remain permanently.
In order to achieve this object, there is provided a method of making a part with a cavity by additive manufacturing, the method comprising the steps of:
The outline of the ceiling may be defined sharply by edges that define the ceiling and the wall of the cavity. If this boundary is not sharp, e.g. because of the presence of a connecting fillet, the outline is defined by determining a perimeter from which the overhang angle exceeds a predetermined limit.
Preferably, the slender support presents a star-shaped section with branches extending in respective planes containing receding lines between the facets of the capital.
The invention can be better understood in the light of the following description of a particular implementation of the invention, given with reference to the figures of the accompanying drawings, in which:
Below, the buildup direction (or manufacturing direction, given reference F in the figures) corresponds to the direction in which successive layers of material are built up by the additive manufacturing machine used for manufacturing the part described in detail herein. The buildup direction is usually the vertical direction.
With reference to
The part is then manufactured by additive manufacturing, by building up successive layers to make the supports 14 and 19 and the capitals 10 and 16 at the same time as making the wall 3. This serves to limit the height of the ceiling of the cavity, but at the cost of reinforcing elements being present in the cavity. The presence of these reinforcing elements reduces the volume of the cavity, and it might be necessary to modify the shape of the cavity in order to ensure that it has the same desired volume in spite of the presence of the reinforcing elements. The thickness of the sections of the branches of a column 14 and of the ribs 19 naturally needs to be determined as a function of the capabilities of the manufacturing machine. It is advantageous to set the width of the branches and of the ribs to a minimum value in order to save on material and to minimize the impact on the volume of the cavity, while nevertheless enabling capitals to be manufactured on tops of the column and of the ribs.
As shown in
The invention is not limited to the above description, but on the contrary covers any variant coming within the ambit defined by the claims. In particular, although in the example shown, the slender support of the central zone is a column of star-shaped section with flat branches, any other type of slender support could be used, e.g. such as a cylindrical column of circular section, a conical column, or indeed an openwork column, providing it starts from the apex of the capital and extends to the floor of the cavity. Although above, only one central portion is shown in the subdivision of the ceiling, the central zone of the ceiling could be subdivided into a plurality of portions in order to reduce the surface areas of the portions and thus the height of the associated capitals, which would imply that a plurality of slender supports are present.
Number | Date | Country | Kind |
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1855287 | Jun 2018 | FR | national |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2019/065751 | 6/14/2019 | WO | 00 |
Publishing Document | Publishing Date | Country | Kind |
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WO2019/238951 | 12/19/2019 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
9636869 | Kroll et al. | May 2017 | B2 |
20160200051 | Urbanic | Jul 2016 | A1 |
20180361096 | Grashow | Dec 2018 | A1 |
20190117408 | Willis | Apr 2019 | A1 |
20190209345 | LaChappelle | Jul 2019 | A1 |
20210077267 | Morrison | Mar 2021 | A1 |
Number | Date | Country |
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10 2010 046 579 | Mar 2012 | DE |
3 026 638 | Jun 2016 | ER |
Entry |
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International Search Report for PCT/EP2019/065751, dated Sep. 4, 2019. |
Number | Date | Country | |
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20210252794 A1 | Aug 2021 | US |