Additively Manufactured Representative Witness Coupon Techniques

1 . A method of additively manufacturing a witness coupon, the method comprising:

determining a build volume of a witness coupon;

determining an orientation of the witness coupon to replicate a property of a part;

preparing a build plate for additive manufacturing the witness coupon;

securing a fixture to an additive manufacturing system;

electrically coupling and grounding the fixture and the additive manufacturing system;

depositing a first layer of a material on the build plate;

depositing a layer of the material on the part;

depositing additional sequential layers of the material on the first layer of a material on the build plate forming the witness coupon;

manufacturing the witness coupon concurrently layer by layer with the part;

wherein the sequential layers are configured to be representative of at least one property of the concurrently manufactured part.

2 . The method of claim 1 further comprising, post-processing the witness coupon to match post-processing conditions of the part.

3 . The method of claim 1 further comprising, extracting at least one test sample from the witness coupon.

4 . The method of claim 3 further comprising, subjecting the at least one test sample to a quality assurance test selected from the group consisting of non-destructive evaluation, destructive testing, statistical analysis to validate the additive manufacturing process.

5 . The method of claim 1 wherein, the build volume of the witness coupon is configured for a testing standard.

6 . The method of claim 1 wherein, wherein the at least one property is selected from the group consisting of grain structure and stress orientations.

7 . The method of claim 1 wherein, depositing the first layer of the material onto the build plate forms an interaction zone of the coupons and an interface between the witness coupon and the build plate.

8 . The method of claim 1 wherein, the additional sequential layers are deposited with a process parameter representative of the part the process parameter is selected from the group consisting of heat input, deposition rate, and cooling.

9 . An apparatus for additively manufacturing a witness coupon, the apparatus comprising:

a fixture secured to an additive manufacturing system, the fixture being electrically coupled and grounded to the additive manufacturing system;

wherein the fixture comprises a build plate configured to support the deposition of a material for a witness coupon;

a material deposition system configured to deposit a first layer of the material onto the build plate and additional sequential layers of the material onto the first layer;

wherein the material deposition system sequentially print layers of the coupon and the part and is configured so that the layers of the coupon are representative of a property of the part; and

wherein the witness coupon and the part are manufactured concurrently.

10 . The apparatus of claim 9 wherein, the property of the part is selected from the group consisting of heat input, deposition rate, cooling, grain structure and stress orientations.

11 . The apparatus of claim 9 wherein, an orientation of the witness coupon is optimized for printing and configured to replicate properties of a concurrently printed part.

12 . The apparatus of claim 9 wherein, the witness coupon is disposed at an electrical extremity from a grounding point.

13 . The apparatus of claim 9 wherein, the fixture is configured so that the witness coupon is located proximal to the part.

14 . The apparatus of claim 13 wherein, the fixture location is further configured to decrease a distance between the part and the coupon.

15 . A method of additively manufacturing a witness coupon, the method comprising:

mounting a part to a build plate of an additive manufacturing system, wherein the part is mechanically coupled to the build plate and electrically coupled to the build plate;

mounting a coupon fixture to the part, wherein the coupon fixture is mechanically coupled to the part and electrically coupled to the part;

depositing, by the additive manufacturing system, a layer of a feature on the part by melting a material onto the part using an electrical current flowing through the material, the part, and the build plate; and

depositing, by the additive manufacturing system, a layer of a witness coupon on the coupon fixture by melting the material onto the coupon fixture using an electrical current flowing through the material, the coupon fixture, the part, and the build plate.

16 . The method of claim 15 , further comprising repeating the steps of the depositing the layer of the feature and of the depositing the layer of the witness coupon until the feature has been additively manufactured and the witness coupon has been additively manufactured.

17 . The method of claim 15 , further comprising cooling the witness coupon on the coupon fixture by cooling the coupon fixture using coolant flowing through the coupon fixture, the part, and the build plate.

18 . The method of claim 15 , further comprising:

mounting a second coupon fixture to the build plate, wherein the second coupon fixture is mechanically coupled to the build plate and electrically coupled to the build plate; and

depositing, by the additive manufacturing system, a layer of a second witness coupon on the second coupon fixture by melting the material onto the second coupon fixture using an electrical current flowing through the material, the second coupon fixture, and the build plate.

19 . The method of claim 15 , further comprising:

mounting a second coupon fixture to an external support, wherein the second coupon fixture is mechanically coupled to the external support; and

depositing, by the additive manufacturing system, a layer of a second witness coupon on the second coupon fixture by melting the material onto the second coupon fixture using an electrical current flowing through the material and the second coupon fixture.

20 . The method of claim 15 , further comprising:

depositing, by the additive manufacturing system, a layer of a second witness coupon on the build plate by melting the material onto the build plate using an electrical current flowing through the material and the build plate.