# US 10,500,835 B2 · In situ monitoring of direct ink write process using electromagnetic resonant coupling

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- Number: US 10,500,835 B2
- Document ID: US10500835B2
- Status: Granted
- Kind: B2
- Application number: 15/290,611
- Filed: 2016-10-11
- Published: 2018-04-12
- Granted: 2019-12-10
- Earliest claimed: 2016-10-11
- Assignees: Lawrence Livermore National Security, LLC
- Applicants: Lawrence Livermore National Security, LLC
- Inventors: Manyalibo Joseph Matthews; Eric Duoss
- Web page: https://patentgrep.com/patent/US10500835B2

## CPC

- B29C 35/0805: {using electromagnetic radiation}
- B29C 64/00: 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
- B29C 64/106: using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material
- B29C 64/112: using individual droplets, e.g. from jetting heads
- B29C 64/209: Heads; Nozzles
- B29C 64/386: Data acquisition or data processing for additive manufacturing
- B29C 64/393: for controlling or regulating additive manufacturing processes
- B33Y 10/00: Processes of additive manufacturing
- B33Y 30/00: Apparatus for additive manufacturing; Details thereof or accessories therefor
- B33Y 50/02: for controlling or regulating additive manufacturing processes
- G01R 27/2605: {Measuring capacitance (capacitive sensors G01D5/24)}
- G01R 27/2611: {Measuring inductance}
- B29C 2035/0811: {using induction}
- B29C 2035/0861: {using radio frequency}
- B29K 2105/0058: {Liquid or visquous}
- G01N 2021/1748: {Comparative step being essential in the method}
- G01N 2021/8405: {Application to two-phase or mixed materials, e.g. gas dissolved in liquids}
- G01N 2021/8411: {Application to online plant, process monitoring}
- G01N 2021/8416: {and process controlling, not otherwise provided for}
- 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
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)
- B29K: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR {MOULDS, } REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)

## Abstract

In the additive manufacturing process, a monitored or controlled mixture of materials is deposited to form an additive manufactured product by delivering the mixture of materials through a material flow path while using an excitation source to introduce electromagnetic energy into the material flow path using a circuit element having inductive or capacitive reactance disposed adjacent the material ejecting orifice. The excitation source produces an electromagnetic field condition within the material flow path that is responsive to at least one of the permeability and permittivity properties of a space within the material flow path. A sensing means coupled electrically or magnetically to the excitation means is responsive to the electromagnetic field condition and provides at least one control parameter based on the electromagnetic field condition that may be used to control the composition of the mixture of materials by adjusting proportions of constituent materials.

## Claims

### Claim 1

An apparatus for depositing a controlled mixture of materials to form an additive manufactured product, comprising:
a means for defining a material flow path;
a means for delivering a controlled mixture of materials through said material flow path, where a constitution of the controlled mixture is established by manipulating at least one control parameter;
an excitation means for introducing electromagnetic energy into the material flow path;
the excitation means producing an electromagnetic field condition within the material flow path that is responsive to at least one of the permeability and permittivity properties of a space within the material flow path;
a sensing means coupled electrically or magnetically to the excitation means and responsive to the electromagnetic field condition;
the sensing means providing the at least one control parameter based on the electromagnetic field condition.

### Claim 2 (depends on 1)

The apparatus of claim 1 wherein the means for defining a material flow path is defined by a nozzle having an orifice through which the controlled mixture is ejected for forming the additive manufactured product.

### Claim 3 (depends on 2)

The apparatus of claim 2 wherein the means for introducing electromagnetic energy into the material flow path comprises an inductor disposed about the nozzle.

### Claim 4 (depends on 3)

The apparatus of claim 3 wherein the inductor is disposed about the nozzle adjacent the orifice.

### Claim 5 (depends on 2)

The apparatus of claim 2 wherein the means for introducing electromagnetic energy into the material flow path comprises a capacitor having plates disposed about the nozzle.

### Claim 6 (depends on 5)

The apparatus of claim 5 wherein the capacitor plates are disposed about the nozzle adjacent the orifice.

### Claim 7 (depends on 1)

The apparatus of claim 1 wherein the means for introducing electromagnetic energy into the material flow path comprises a circuit component having inductive or capacitive reactance.

### Claim 8 (depends on 1)

The apparatus of claim 1 wherein the excitation means comprises an electromagnetic frequency generator.

### Claim 9 (depends on 1)

The apparatus of claim 1 wherein the excitation means comprises a broadband signal generator.

### Claim 10 (depends on 1)

The apparatus of claim 1 wherein the means for introducing electromagnetic energy into the material flow path comprises a first inductor and the sensing means comprises a second inductor magnetically coupled to the first inductor.

### Claim 11 (depends on 1)

The apparatus of claim 1 wherein the means for introducing electromagnetic energy into the material flow path comprises an inductor and the sensing means comprises a capacitor coupled to the inductor to define a tank circuit.

### Claim 12 (depends on 1)

The apparatus of claim 1 wherein the means for delivering a controlled mixture of materials includes at least one valve that is electrically controlled by the sensing means.

### Claim 13 (depends on 1)

The apparatus of claim 1 wherein the means for delivering a controlled mixture of materials includes at least one valve that is electrically controlled by the sensing means in real time as the additive manufactured product is being formed.

### Claim 14 (depends on 1)

The apparatus of claim 1 wherein the constitution of the controlled mixture is established before the additive manufactured product is formed and wherein the sensing means provides the at least one control parameter to validate the quality of the additive manufactured product in real time as the product is being formed.

### Claim 15 (depends on 1)

The apparatus of claim 1 wherein the excitation means produces electromagnetic energy of at least one optical wavelength and wherein the means for defining a material flow path includes a window structure that is optically transparent at the at least one optical wavelength.

### Claim 16 (depends on 1)

The apparatus of claim 1 wherein the means for introducing electromagnetic energy into the material flow path comprises a capacitor and the sensing means comprises an inductor coupled to the capacitor to define a tank circuit.