Hewlett-packard Development Company, L.p.

Other

Xavier Vilajosana

Alejandro Manuel De Pena

Sebastia Cortes I Herms

Pere Tuset

David Ramirez Muela

Sergio Puigardeu Aramendia

Sebastia Cortes

Sheila Cabello

Jun Zeng

Scott A White

Esteve Comas

Pol Fornos

Pablo Dominguez Pastor

Diego Javier Mostaccio

Luis Garcia

Yngvar Rossow

Pablo Dominguez

Anna Tarradas

Marina Ferran Farras

Examples include apparatuses, processes, and methods for generating three-dimensional objects. An example apparatus comprises build material distributor and a controller. Examples distribute a particular build layer in a build area of the apparatus over a previous build layer. Examples determine a build layer temperature corresponding to the particular build layer. Examples analyze build layer coverage for the particular build layer based at least in part on a build layer temperature of the previous build layer and the build layer temperature of the particular build layer. Examples selectively recoat the particular build layer with additional build material based at least in part on the build layer coverage for the particular build layer.

Build layer coverage analysis

In an example, a method of anticipating maintenance in a printing device includes determining an inertial reference signal of a printer carriage and measuring a current inertial signal of the printer carriage. The method includes cross-correlating the inertial reference signal with the current inertial signal and determining from the cross-correlating when the current inertial signal is not within a preset confidence interval of the inertial reference signal.

Anticipating maintenance in a printing device

In an example, a method includes forming a first layer of build material to be processed in object generation and selectively applying at least one print agent on to the first layer based on a print instruction for the first layer. Energy may be applied to the first layer to cause fusion in at least a region thereof, and at least one temperature associated with a thermal contribution of the first layer to a subsequent layer of build material to be processed in object generation may be measured. It may be determined if a temperature condition indicative of a departure from an anticipated thermal contribution of the first layer to a region of subsequent layer exists. If such a temperature condition does exist, a print instruction for applying print agent to the region of the subsequent layer based on the temperature condition may be determined.

Managing thermal contributions between layers during additive manufacturing

According to some examples, a method comprises measuring, using a detector, a temperature of at least a portion of a layer of build material formed on a print bed associated with an additive manufacturing apparatus. The additive manufacturing apparatus may include a heating module to direct heat towards successive layers of build material during a series of successive passes over the build material. The method may further comprise determining, using a processor, based at least in part on the measured temperature, a duration that the heating module is to wait before performing a pass over the build material, and a speed at which the heating module is to travel over the build material.

Controlling heating in additive manufacturing

According to an example, a printer may include a warming device to apply energy onto a region of a plurality of regions of a layer of build materials. The printer may also include a controller that may calculate, based upon the region upon which the warming device is to apply energy, an energy curve to be applied to the warming device between occurrences of a plurality of events, in which the energy curve defines timings and levels at which the warming device is to be operated between occurrences of the plurality of events. The controller may also control the warming device to be operated to apply energy onto the region according to the calculated energy curve.

Printer warming device control

In one example, a method of controlling generation apparatus for generating a three-dimensional object is described. For example, data indicative of at least one physical property affecting heat transfer from an object may be determined and used to determine a cooling time, and a component of the generation apparatus may be controlled in response to the determined cooling time.

Cooling times for three-dimensional objects

A method of controlling a heating sub-system in an additive manufacturing system. The method comprising receiving thermal imaging information from a temperature sensing subsystem, receiving additive manufacturing media concentration information from an additive manufacturing media concentration information database, on the basis of the received thermal imaging information and additive manufacturing media concentration information, for each pixel area in the plurality of pixel areas, determining the temperature for each additive manufacturing media agent in the plurality of additive manufacturing media agents which is present in the respective pixel area, and on the basis of the determined temperatures for each pixel area and additive manufacturing media agent, controlling the power to a heating subsystem employed in the given additive manufacturing process.

Temperature determination in additive manufacturing systems

In an example, a method includes measuring the temperature of a fused region and the temperature of an unfused region of a first layer of build material; determining a preheating setting for a subsequent layer of build material in response to the measured temperature of the unfused region of the first layer; determining a print instruction for applying print agent to the subsequent layer of build material, wherein the application of print agent prescribed by the print instruction for the subsequent layer to cause the temperature of the preheated build material to be a predetermined temperature prior to fusion in response to the measured temperature of the fused region of the first layer; forming the subsequent layer of build material; preheating the subsequent layer of build material in accordance with the preheating setting; and selectively applying the print agent onto the subsequent layer based on the print instruction.

Temperature control prior to fusion

In an example, a print apparatus includes a printhead carriage to receive a printhead comprising a print agent ejection nozzle, a drop detector to acquire a signal indicative of variations in a parameter detected by the drop detector over a period of drop detection, a memory to hold a print agent ejection signature, and processing circuitry. The processing circuitry includes a convolution module to convolve the drop detector signal with the print agent ejection signature, and the processing circuitry is to determine, from an output of the convolution module, an indication of similarity between the drop detector signal and the print agent ejection signature.

Indications of similarity for drop detector signals

In some examples, a method comprises sensing a temperature of a plurality of sub-regions of a portion of a layer of build material in an object generation apparatus. A frequency distribution of sub-region temperatures may be derived therefrom and it may be determined whether the frequency distribution is bimodal. If the frequency distribution is not bimodal, a build material temperature zone is identified. If however the frequency distribution is bimodal, a fusing build material temperature zone and a non-fusing build material temperature zone are identified. The method may further comprise determining a nominal temperature of the at least one identified temperature zone.

Object generation temperature measurement

A method and apparatus partition a AM build bed of a AM unit into a first virtual build bed and a second virtual build bed. The first virtual build bed is assigned to a first user while the second virtual build bed assigned to a second user. A first digital file for a first object to be generated in the first virtual build bed is received from the first user. A second digital file for a second object to be generated in the second virtual build bed is receive from the second user. Output signals are transmitted to the AM unit to generate the first object in the first virtual build bed and the second object in the second virtual build bed during a build cycle.

Virtual build beds

In an example, a printhead maintenance apparatus includes a pump, a current monitor and processing circuitry. The pump may be provided to increase a pressure in a printhead, and the current monitor may monitor a current consumption of the pump. The processing circuitry may determine a rate of change of current consumption of the pump, and compare the rate of change of current consumption to a predetermined threshold.

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Sant Cugat del Valles, Spain

Xavier Vilajosana