A method of making a fuel grain for use in a rocket motor, the method comprising blending a first energetic nanoscale metallic compound and a second compound suitable to form a feedstock material for use in an additive manufacturing apparatus, the additive manufacturing apparatus operatively connected to a computing system, that provides additive manufacturing printing instructions to the additive manufacturing apparatus, permitting construction of an autonomously designed and optimized rocket fuel grain section; wherein the stochastic deposition simulation-assisted fuel grain geometries further comprise a plurality of agglutinated layers of solidified fuel grain compound, each layer of the plurality of layers comprising a plurality of blended and radially displaced beads of different radii, said radial displacement optionally optimized via competitive simulation programs, and wherein the system continuously mixes constituent materials in an inline/static mixer, with viscosity controlled via particle size variations, and material is deposited in a controlled atmosphere or vacuum.

A hybrid rocket solid fuel grain having a cylindrical shape and defining a center port is additive manufactured from a compound of thermoplastic fuel and passivated nanocomposite aluminum additive. The fuel grain comprises a stack of fused layers, each layer formed as a plurality of fused abutting concentric circular beaded structures arrayed to define a center port. During operation, an oxidizer is introduced along the center port, with combustion occurring along the exposed port wall. Each circular beaded structure defines geometry that increases the surface area available for combustion. As each layer ablates the next abutting layer, exhibiting a similar geometry, is revealed, undergoes a gas phase change, and ablates. This process repeats and persists until oxidizer flow is terminated or the fuel grain material is exhausted. To safely achieve this construction, a fused deposition additive manufacturing apparatus, modified to shield the nanocomposite material from the atmosphere, is used.

A method of additively manufacturing propellant elements, such as for rocket motors, includes partially curing a propellant mixture before extruding or otherwise dispensing the material, such that the extruded propellant material is deposited on the element in a partially-cured state. The curing process for the partially-cured extruded material may be completed shortly after the material is put into place, for example by the material being heated at or above its cure temperature, such that it finishes curing before it fully cools. The propellant material may be prepared by first mixing together, a fuel, an oxidizer, and a binder, such as in an acoustic mixer. After that mixing a curative may be added to the mixture. The propellant mixture may then be directed to an extruder (or other dispenser), in which the mixture is heated to or above a cure temperature prior to the deposition, and then deposited.

A carpet pellet machine and method are disclosed. One embodiment provides an apparatus comprising a compressor to receive fibrous material and compress the fibrous material, a mold pipe system to receive compressed fibrous material from the compressor, wherein the compressor is configured to press the fibrous material through the mold pipe system, and a heat chamber to heat the fibrous material within the mold pipe system and create an encapsulation layer on the fibrous material.

A method of making a multi-grained fuel grain for a rocket is disclosed, the method comprising the steps of using at least one nozzle to extrude a first propellant in an additive manufacturing process, the first propellant comprising a multi-grained fuel grain, the multi-grained fuel grain forming the at least one void, the at least one void facilitating variation in internal ballistics, forming sensors, said sensors permitting continuous monitoring and continuous modification such that a user controls the ballistics profile of a rocket motor, forming an electrically-controlled second propellant in contact with and operatively coupled to the sensors; and wherein the additive manufacturing process uses at least at least one nozzle to extrude raw materials.

A method includes depositing beads of solid propellant material using additive manufacturing to form a fuel element for a rocket engine, the fuel element including beads of solid propellant material, wherein a combustion port extends through the fuel element, wherein the solid propellant material includes an oxidizer and a binder material.

A rocket motor comprising a non-permeable outer shell, an intra-wall channel between the non-permeable outer shell and an annular section, and a center chamber formed at least in part by a first propellant is disclosed. The first propellant is made up of a multi-grained fuel grain, and the center chamber is further formed by an annular section. The intra-wall channel is configured to permit combustion gases to flux between the non-permeable outer shell and the annular section. The annular section configured to permit combustion gases to flux through pores embedded within the annular section.

The invention is directed to a method for the preparation of an energetic material product such as a propellant or explosive charge or grain. The method includes additive manufacturing with co-extrusion of at least two materials to form a multi-layered filament and layer-by-layer deposition of the multi-layered filament. The multi-layered filament has a first material layer and a second material layer and at least one layer includes an energetic material. In another aspect, the invention is directed to an apparatus for use in this method, the apparatus comprising a co-extrusion nozzle.

A method for making a unitary fuel grain for use in a rocket motor or gas generator comprising forming a fuel grain coating substantially free of gas-permeable voids, forming a succession of additional coats of oxidizer depleted grain material substantially free of gas-permeable voids. The fuel grain is then deposited into a print bed along a predetermined distance in a direction primarily parallel to a rocket motor central axis, the fuel grain coating forming a rocket motor fuel grain having a pre-ignition segment and a post-ignition segment, wherein the passivated fuel grain coating of fuel grain material is continuously self-adhered during fuel grain material deposition, and wherein the fuel grain material comprises oxidizer depleted fuel grain material; and wherein the passivated fuel grain coating of fuel grain material forms a substantially circular pattern upon deposition, said substantially circular pattern having an outer shell with an undulating pattern.