Additive manufacturing process for producing chemical delivery devices using halftone screening

1 . A method of producing a chemical delivery device with a three-dimensional object printer comprising:

receiving with a controller a first concentration parameter for a first active chemical in a first region of a substrate in the chemical delivery device;

generating with the controller halftoned image data using a stochastic halftone screen and with reference to the first concentration parameter, the halftoned image data including a plurality of activated pixels that correspond only to locations of a first portion of a plurality of cavities formed in a substrate that receive the first active chemical; and

ejecting with at least a first ejector a predetermined amount of a first chemical carrier including the first active chemical into each cavity in the first portion of the cavities in the substrate with reference to the halftoned image data to produce the chemical delivery device with a concentration of the first active chemical corresponding to the first concentration parameter.

2 . The method of claim 1 further comprising:

prior to ejecting the predetermined volume of the first chemical carrier including the first active chemical, forming, with a dispenser, the substrate from a plurality of layers including an excipient material.

3 . The method of claim 2 , the forming of the substrate further comprising:

applying with a spreader a powdered excipient material; and

operating at least a second ejector to eject a liquid binder in a predetermined pattern to bind portions of the excipient material to form the substrate.

4 . The method of claim 2 , the forming of the substrate further comprising:

operating at least a second ejector to eject liquid drops of the excipient material in a predetermined pattern to form the substrate.

5 . The method of claim 1 further comprising:

receiving with the controller a plurality of concentration parameters of the first active chemical for a plurality of regions of the chemical delivery device;

generating with the controller the halftoned image data using the stochastic halftone screen with reference to the plurality of concentration parameters; and

ejecting with the at least first ejector the predetermined amount of the first chemical carrier including the first active chemical into the first portion of the cavities in the substrate with a concentration gradient through the plurality of regions of the chemical delivery device corresponding to the plurality of concentration parameters.

6 . The method of claim 1 further comprising:

receiving with the controller a second concentration parameter for a second active chemical in the first region of the substrate in the chemical delivery device;

generating with the controller the halftoned image data using the stochastic halftone screen with reference to the second concentration parameter, the halftoned image data including a second plurality of activated pixels that correspond only to locations of a second portion of the plurality of cavities formed in the substrate that receive the second active chemical, wherein the stochastic halftone screen further comprises a stochastic vector halftone screen; and

ejecting with at least a second ejector a predetermined amount of a second chemical carrier including the second active chemical into each cavity in the second portion of the cavities in the substrate with reference to the halftoned image data to produce the chemical delivery device with a concentration of the second active chemical corresponding to the second concentration parameter.

7 . The method of claim 6 wherein the controller generates the second plurality of activated pixels only in locations of the halftoned image data corresponding to cavities in the substrate that do not correspond to any of the first plurality of activated pixels.

8 . The method of claim 1 further comprising:

operating a dispenser to form excipient material in any cavity in the plurality of cavities that does not receive the first chemical carrier including the first active chemical.

9 . The method of claim 1 further comprising:

after ejecting the predetermined volume of the first chemical carrier including the first active chemical, forming, with a dispenser, a plurality of layers of an excipient material over the substrate and the plurality of cavities to cover the plurality of cavities and to form another plurality of cavities in another layer of the substrate of the chemical delivery device.