# US 11,733,678 B2 · Method for determining building instructions for an additive manufacturing method, method for generating a database with correction measures for controlling the process of an additive manufacturing method

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- Number: US 11,733,678 B2
- Document ID: US11733678B2
- Status: Granted
- Kind: B2
- Application number: 17/251,553
- Filed: 2019-06-03
- Published: 2021-08-19
- Granted: 2023-08-22
- Earliest claimed: 2018-06-12
- Assignees: Siemens Aktiengesellschaft
- Applicants: Siemens Aktiengesellschaft
- Inventors: Frank Heinrichsdorff; Darya Kastsian; Ursus Krüger; Daniel Reznik; Heinz Neubert
- Web page: https://patentgrep.com/patent/US11733678B2

## CPC

- G05B 19/4099: Surface or curve machining, making three-dimensional [3D] objects, e.g. desktop manufacturing
- B22F 10/36: of energy beam parameters
- B22F 10/368: Temperature or temperature gradient, e.g. temperature of the melt pool
- B22F 10/85: for controlling or regulating additive manufacturing processes
- B29C 64/153: using layers of powder being selectively joined, e.g. by selective laser sintering or melting
- B29C 64/393: for controlling or regulating additive manufacturing processes
- B33Y 10/00: Processes of additive manufacturing
- B33Y 50/00: Data acquisition or data processing for additive manufacturing
- B33Y 50/02: for controlling or regulating additive manufacturing processes
- B22F 10/28: Powder bed fusion, e.g. selective laser melting [SLM] or electron beam melting [EBM]
- B22F 10/47: characterised by structural features
- B22F 12/49: Scanners
- B22F 12/67: Blades
- B22F 12/90: Means for process control, e.g. cameras or sensors
- G05B 2219/49013: Deposit layers, cured by scanning laser, stereo lithography SLA, prototyping
- G05B 2219/49214: Estimate error from heat distribution model and drive current, correct error
- Y02P 10/25: Process efficiency
- G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G)
- B22F: WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER (making alloys by powder metallurgy C22C); APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- B33Y: ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

Various embodiments include a method for additive manufacturing of a building structure on using a simulation comprising: accessing a data set for the building structure describing the building structure in layers; calculating a global heat development in previous layers based a building history and heat input by an energy beam; determining a local heat development in a vicinity of the heat input; determining the process control based on the global and the local heat development; loading correction measures from a database; and assigning the correction measures locally to individual vectors of a tool path of the energy beam. At least one mass integral is calculated for individual vectors of the tool path. The measures are determined on the basis of a comparison of the calculated mass integral with mass integrals stored in the database.

## Claims

### Claim 1

A method for determining building specifications describing process control for the additive manufacturing of a building structure on the basis of a simulation of the manufacture of the building structure, the method comprising:
accessing a manufacturing data set for the building structure, the manufacturing data set describing the building structure in layers to be manufactured;
calculating a global heat development in already manufactured layers of the building structure based at least in part on a building history of the building structure and heat input by an energy beam;
determining a local heat development in a vicinity of the heat input by the energy beam;
determining the process control based at least in part on the global heat development and the local heat development;
loading correction measures of the process control from a database based at least in part on the global heat development and the local heat development; and
assigning the correction measures locally to individual vectors of a tool path of the energy beam; wherein
at least one mass integral is calculated for individual vectors of the tool path; and
correction measures are determined on the basis of a comparison of the calculated mass integral with mass integrals stored in the database.

### Claim 2 (depends on 1)

The method as claimed in claim 1, wherein the correction measures of the process control are determined in such a way that a melt pool produced by the energy beam has a size that is in a defined interval.

### Claim 3 (depends on 1)

The method as claimed in claim 1, further comprising calculating a mass integral for individual vectors of the tool path over a defined integration volume;
wherein the integration volume contains a part of the surface of the building structure facing the energy beam; and
wherein a point of the vector considered lies in the integration volume.

### Claim 4 (depends on 3)

The method as claimed in claim 3, further comprising calculating at least one mass integral at the beginning and one mass integral at the end of the vector for the vectors.

### Claim 5 (depends on 4)

The method as claimed in claim 4, further comprising selecting, from the mass integrals calculated per vector, a mass integral with a lowest value.

### Claim 6 (depends on 4)

The method as claimed in claim 4, further comprising calculating a value corresponding to a mean value of the mass integrals from the mass integrals calculated per vector.

### Claim 7 (depends on 3)

The method as claimed in claim 3, wherein in order to determine the correction measures for a vector considered:
the calculated mass integral is compared with mass integrals stored in the database;
that stored mass integral most similar to the calculated mass integral is selected from the database; and
the correction measures of the process control stored with the selected mass integral are selected for the vector considered.

### Claim 8 (depends on 3)

The method as claimed in claim 3, wherein to determine the correction measures in the form of correction values for a vector considered:
the calculated mass integral is compared with mass integrals stored in a database;
those stored mass integrals which are the most similar to the calculated mass integral are selected from the database; and
the correction values for process parameters of the process control stored with the selected mass integrals are selected for the vector considered and an interpolation of said correction values is carried out, wherein the result of the interpolation is used as a resulting correction value for the correction.

### Claim 9 (depends on 3)

The method as claimed in claim 3, wherein the mass integral has the shape of an ellipsoid or of a semi-ellipsoid having a semi-axis δr in the x-y-plane of the layer to be manufactured and δz in the z-direction.

### Claim 10 (depends on 1)

The method as claimed in claim 1, wherein the correction measures include at least one of: a reduction of the power of the energy beam, a lengthening of the pause times between the irradiation times of individual vectors, an increase of the movement speed of the energy beam, an increase of the hatch distance between the vectors, an alteration of the vector order, an alteration of the vector length, an alteration of the vector orientation.

### Claim 11

A method for determining correction measures for building specifications describing process control for additive manufacturing of building structures on the basis of a simulation, the method comprising:
defining process parameters for the process control are defined;
accessing a manufacturing data set for the building structure, said manufacturing data set describing the building structure in layers to be manufactured;
assessing a global heat development in the form of a reference temperature;
calculating local heat development in the vicinity of the heat input by an energy beam;
calculating the local heat development in the vicinity of the heat input by the energy beam for representative volume elements with a predefined geometry;
if a calculated heat development exceeds a threshold, assigning correction measures of the process control locally to individual vectors of a tool path of the energy beam;
calculating a mass integral over a partial volume of the representative volume element in which the correction measures are required; and
storing the correction measures with the associated mass integral in a database.

### Claim 12 (depends on 11)

The method as claimed in claim 11, wherein the representative volume elements have the shape of
parallelepipeds,
prisms having two lateral surfaces extending parallel to the layers and at least one lateral surface extending at an inclination to the layers and connecting the parallel lateral surfaces, and/or
triangular prisms having a lateral surface extending parallel to the layers.

### Claim 13 (depends on 11)

The method as claimed in claim 11, further comprising using a parallelepipedal representative volume element, the boundary of which is surrounded all around by the material of the building structure, to ascertain reference values for the process control;
wherein the correction parameters aim to reduce the energy input of the energy beam.

### Claim 14 (depends on 11)

The method as claimed in claim 11, further comprising calculating a melt pool size by calculating the mass integral over a partial volume of the representative volume element containing a part of the surface of the representative volume element facing the energy beam, localized on a plurality of points of the tool path;
wherein for said points the melt pool size is calculated taking account of the local heat development and the reference temperature.

### Claim 15 (depends on 11)

The method as claimed in claim 11, wherein the mass integral has the shape of an ellipsoid or of a semi-ellipsoid having a semi-axis δr in the x-y-plane of the layer to be manufactured and δz in the z-direction.