Method For Producing At Least One Component In A 3D Printing Method, And 3D Printer

Abstract

Disclosed is a method of manufacturing at least one component by 3D printing on a construction platform provided with a heating device, the method comprising: applying a layer of loose particulate material to the construction platform, heating the applied layer of loose particulate material by means of the heating device of the construction platform, outputting a liquid treatment agent onto a partial area of the heated layer of loose particulate material, and repeating said steps to build up the at least one component in layers. The heating by means of the heating device of the construction platform is carried out in such a manner that a temperature of the construction platform increases toward a predetermined construction platform maximum temperature during the build-up of the component to set a surface temperature of the respectively last applied layer.

Claims

1. Method of manufacturing at least one component by 3D printing on a construction platform provided with a heating device, comprising the steps of: applying a layer of loose particulate material to the construction platform, heating the applied layer of loose particulate material by means of the heating device of the construction platform, outputting a liquid treatment agent onto a partial area of the heated layer of loose particulate material, repeating the above steps to build up the at least one component, wherein the heating is carried out by means of the heating device of the construction platform in such a way that a temperature of the construction platform increases toward a predetermined construction platform maximum temperature during the build-up of the component to set a surface temperature of the respectively last applied layer.

2. Method according to claim 1, wherein the heating is carried out by means of the heating device of the construction platform in such a way that the construction platform is heated during the build-up of the component until the predetermined construction platform maximum temperature is reached.

3. Method according to claim 2, wherein the heating is carried out by means of the heating device of the construction platform in such a way that the temperature of the construction platform is maintained at the predetermined construction platform maximum temperature during the build-up of the component after the predetermined construction platform maximum temperature is reached.

4. Method according to claim 1, wherein the predetermined construction platform maximum temperature is in a range of 180-320° C., for example 200-300° C., for example 220-280° C., for example 240-260° C., and/or is selected depending on the treatment agent and/or the particulate material.

5. Method according to claim 1, wherein the surface temperature of the respectively last applied layer is set to a temperature in a range of 30-70° C., for example 35-65° C., for example 40-60° C., for example 45-55° C., as long as the predetermined construction platform maximum temperature is not reached, for example a constant temperature and/or a temperature selected depending on the treatment agent.

6. Method according to claim 1, wherein the setting of the surface temperature of the respectively last applied layer is carried out by means of a temperature control using a set value specification for the surface temperature as long as the predetermined construction platform maximum temperature has not been reached.

7. Method according to claim 1, wherein the surface temperature is sensed by at least a first temperature sensor and/or the temperature of the construction platform is sensed by at least a second temperature sensor.

8. Method according to claim 7, wherein a first temperature value sensed by the first temperature sensor is compared to the set value specification wherein the setting of the surface temperature of the respectively last applied layer is carried out by means of a temperature control using a set value specification for the surface temperature as long as the predetermined construction platform maximum temperature has not been reached, and/or a second temperature value sensed by the second temperature sensor is compared to the predetermined construction platform maximum temperature.

9. Method according to claim 1, wherein the construction platform is configured to be fluid-impermeable and/or the heating of the applied layers of loose particulate material is carried out in the absence of a fluid flow and/or the heating of the applied layers of loose particulate material is carried out in the absence of a heating device provided above the respectively last applied layer.

10. Method according to claim 1, wherein the heating device is arranged at, for example on, and/or in the construction platform.

11. Method according to claim 1, wherein the liquid treatment agent comprises an organic binding agent, for example a phenol-based binding agent, for example a phenolic resin, or a furan-based binding agent, for example a furan resin, or an inorganic binding agent, for example a waterglass-based binding agent, for example a waterglass, and/or the particulate material comprises sand particles and/or salt particles and/or metal particles, and/or the component is a casting core and/or a casting mold.

12. Method according to claim 1, wherein the construction platform is maintained at the predetermined construction platform maximum temperature for a predetermined period of time after completion of the at least one component.

13. (canceled)

14. (canceled)

15. (canceled)

Description

[0051] FIG. 1 shows a (schematic) diagram of a temperature curve of the construction platform temperature according to a first embodiment, as it may occur in a method according to the invention.

[0052] FIG. 2 shows a (schematic) diagram of a temperature curve of the construction platform temperature according to a second embodiment, as it may occur in a method according to the invention.

[0053] FIG. 3 shows a (schematic) diagram of a temperature curve of the construction platform temperature according to a third embodiment, as it may occur in a method according to the invention.

[0054] FIG. 4 shows a (schematic) diagram of a temperature curve of the surface temperature of the respectively last applied layer according to a fourth embodiment, as it may occur in a method according to the invention.

[0055] FIG. 5 shows a flow chart of a control sequence according to a fifth embodiment.

[0056] FIG. 6 shows a 3D printer according to a sixth embodiment.

[0057] In the following detailed description, reference is made to the enclosed Figures which are incorporated therein and in which specific embodiments are shown by way of illustration, according to which the invention can be performed.

[0058] It shall be understood that other embodiments may be used and structural or logical changes may be made without deviating from the scope of protection of this invention. It shall be understood that the features of the embodiments described herein may be combined unless specified otherwise. Thus, the following description should not be understood in a restrictive sense and the scope of protection of this invention shall be defined by the attached claims.

[0059] In FIGS. 1 to 3, time t is plotted on the horizontal axis and temperature T of the construction platform is plotted on the vertical axis. In FIG. 4, time t is plotted on the horizontal axis and temperature T of the surface of the respectively last applied layer is plotted on the vertical axis.

[0060] A method of manufacturing at least one component by 3D printing on a construction platform provided with a heating device may comprise the following steps: (1) applying a layer of loose particulate material to the construction platform, (2) heating the applied layer of loose particulate material by means of the heating device of the construction platform, (3) outputting a liquid treatment agent onto a partial area of the heated layer of loose particulate material (according to a section of the component to be manufactured), (4) repeating steps (1) to (3) to build up the at least one component. The heating with the heating device of the construction platform may be performed such that a temperature of the construction platform T.sub.BP increases toward a predetermined construction platform maximum temperature T.sub.BP,max during the build-up of the component, thereby adjusting a surface temperature of the last applied layer T.sub.OF, for example, to a specific value or to a specific temperature range (i.e., the surface temperature is thereby maintained in a specific temperature range).

[0061] For example, as shown in FIG. 1, the temperature of the construction platform T.sub.BP may increase linearly (for example, at a constant temperature change rate).

[0062] As shown in FIG. 2, the temperature of the construction platform T.sub.BP may increase, for example, in a step-like or step-wise manner. For example, the temperature of the construction platform T.sub.BP may first be maintained at a first temperature for a first period of time and then be maintained at a second, increased temperature for a second period of time, and so on.

[0063] As shown in FIG. 3, the temperature of the construction platform T.sub.BP may increase, for example, in a curved manner. For example, the temperature curve may have a temperature profile/progression in which the temperature change rate decreases as the construction platform temperature T.sub.BP approaches the construction platform maximum temperature T.sub.BP,max.

[0064] It shall be understood that alternative curves to the temperature curves of the construction platform temperature shown in FIGS. 1 to 3 are possible. For example, the construction platform temperature may increase linearly for a first period of time at a first temperature change rate and may then increase linearly for a second period of time at a second temperature change rate. For example, the temperature curve may have a temperature profile/progression where the temperature change rate increases as the construction platform temperature T.sub.BP approaches the construction platform maximum temperature T.sub.BP,max.

[0065] For example, the temperature curve of the construction platform temperature may be determined (for example, experimentally) prior to carrying out the 3D printing process, and may be set (using the heating device) in a way to set a surface temperature of the respectively last applied layer T.sub.OF to a predetermined (for example, substantially constant) temperature value or a corresponding range. The predetermined temperature value or range may, for example, be selected depending on the liquid treatment agent. For example, the predetermined temperature value may be selected such that a print head of the 3D printer from which the liquid treatment agent is dispensed is not damaged or impaired (for example, by sticking together of the print module openings due to evaporation of a solvent component).

[0066] As shown in FIGS. 1 to 3, the temperature of the construction platform T.sub.BP can be heated, for example, until the predetermined construction platform maximum temperature T.sub.BP,max is reached.

[0067] As shown in FIGS. 1 to 3, the temperature of the construction platform T.sub.BP may be maintained at the predetermined construction platform maximum temperature T.sub.BP,max for example, after the predetermined construction platform maximum temperature T.sub.BP,max is reached.

[0068] The predetermined construction platform maximum temperature may be, for example, in a range of 100-320° C., for example 125-250° C., for example 150-200° C. The predetermined construction platform maximum temperature may be selected, for example, as a function of the treatment agent and/or the particulate material.

[0069] The surface temperature of the respectively last applied layer T.sub.OF may be set, for example, to a temperature in a range of 30-70° C., for example 30-60° C., for example 30-50° C., for example 30-40° C., for example 35° C., at least as long as the predetermined construction platform maximum temperature T.sub.BP,max is not reached. In this respect, the surface temperature of the respectively last applied layer T.sub.OF may be set, for example, to a (substantially) constant temperature, but it may also move/fluctuate within one of the ranges mentioned or claimed. The surface temperature of the respectively last applied layer T.sub.OF may, for example, be set as a function of the treatment agent.

[0070] The setting of the surface temperature of the respectively last applied layer T.sub.OF via the temperature curve of the heating device may be carried out, for example, by means of a control, by the heating device being operated in accordance with a previously determined temperature curve.

[0071] Alternatively, the setting of the surface temperature may be carried out, for example, by means of a temperature control using a set value specification for the surface temperature, for example, until the predetermined construction platform maximum temperature T.sub.BP,max is reached. Then the temperature curve of the construction platform temperature results from the control of the surface temperature.

[0072] As shown in FIG. 4, the surface temperature of the respectively last applied layer T.sub.OF may be set to a set value for the surface temperature T.sub.OF,set. This may be performed, for example, by means of the temperature control. Alternatively, for example, the temperature curve of the construction platform temperature may be set/controlled such that the surface temperature of the respectively last applied layer T.sub.OF (substantially) corresponds to the set value for the surface temperature T.sub.OF,set.

[0073] As shown in FIG. 4, the surface temperature of the respectively last applied layer T.sub.OF may be increased to the set value for the surface temperature T.sub.OF,set and may then be maintained at this set value. When a certain thickness or height of the applied layers is reached and/or the predetermined construction platform maximum temperature T.sub.BP,max is reached, a decrease in the surface temperature of the respectively last applied layer T.sub.OF may occur (with continued layer application), since the amount of heat emitted by the construction platform may then be too low to maintain the surface temperature of the respectively last applied layer T.sub.OF at the set value.

[0074] The surface temperature of the respectively last applied layer T.sub.OF may, for example, be sensed by at least a first temperature sensor. The temperature of the construction platform T.sub.BP may be sensed, for example, by at least a second temperature sensor. See for example FIG. 6.

[0075] The first temperature sensor may be, for example, an infrared sensor. The first temperature sensor may, for example, substantially sense the surface temperature of the entire construction field or an average value or maximum value thereof. For example, the first temperature sensor may sense the surface temperature of a particular portion of the construction field, the portion comprising, for example, an area of 20% or less (for example, 10% or less, for example, 5% or less) of the total area of the construction field. For example, a plurality of first temperature sensors may also be provided, each sensing a temperature of a predetermined partial area of the construction field surface, wherein, for example, an average value or maximum value of the sensed temperature values may be used as the surface temperature.

[0076] The second temperature sensor may, for example, comprise at least a PTC resistor. For example, a plurality of second temperature sensors may be provided, each sensing a temperature of a predetermined position of the construction platform, wherein, for example, an average value or maximum value of the sensed temperature values may be used as the construction platform temperature.

[0077] A first temperature value T.sub.OF sensed by the first temperature sensor may, for example, be compared to the set value specification T.sub.OF,set (in the case of control). A second temperature value T.sub.BP sensed by the second temperature sensor may be compared, for example, with the predetermined construction platform maximum temperature T.sub.BP,max.

[0078] As shown in FIG. 5, in the context of a control, for example, first the set value for the surface temperature T.sub.OF,set and the construction platform maximum temperature T.sub.BP,max may be set or predetermined, for example depending on the binding agent system and/or particulate material used. The temperature of the construction platform T.sub.BP may then be determined in the method, for example, using the second temperature sensor. The determined construction platform temperature T.sub.BP may then be compared to the construction platform maximum temperature T.sub.BP,max. If the determined construction platform temperature T.sub.BP is equal to (or greater than) the construction platform maximum temperature T.sub.BP,max, the construction platform temperature T.sub.BP may be maintained at the construction platform maximum temperature T.sub.BP,max during the further course of the method, for example. If the determined construction platform temperature T.sub.BP is greater than the construction platform maximum temperature T.sub.BP,max, the construction platform temperature T.sub.BP may be reduced to the construction platform maximum temperature T.sub.BP,max, for example, and then maintained at the construction platform maximum temperature T.sub.BP,max. If the determined construction platform temperature T.sub.BP is less than the construction platform maximum temperature T.sub.BP,max, the surface temperature of the respectively last applied layer T.sub.OF may be determined, for example, with the first temperature sensor. The determined surface temperature T.sub.OF may then be compared to the set value for the surface temperature T.sub.OF,set. If the determined surface temperature T.sub.OF is less than the set value for the surface temperature T.sub.OF,set, the construction platform temperature T.sub.BP may be increased, for example. If the determined surface temperature T.sub.OF is equal to the set value for the surface temperature T.sub.OF,set, the construction platform temperature T.sub.BP may be maintained, for example. If the determined surface temperature T.sub.OF is greater than the set value for the surface temperature T.sub.OF,set, for example, the construction platform temperature T.sub.BP may be decreased.

[0079] For example, the construction platform may be configured to be fluid-impermeable. Heating of the applied layers of loose particulate material may be performed, for example, in the absence of a fluid flow. Heating of the applied layers of loose particulate material may be performed, for example, in the absence of a heating device provided above the respectively last applied layer.

[0080] The heating device (of the construction platform) may be, for example, an electric heating device and may be disposed on and/or in the construction platform.

[0081] The liquid treatment agent may be, for example, an organic binding agent, for example, a phenol-based binding agent (for example, a phenolic resin) or a furan-based binding agent (for example, a furan resin). The liquid treatment agent may be, for example, an inorganic binding agent, for example, a waterglass-based binding agent (for example, a waterglass).

[0082] The construction platform temperature may be maintained at the predetermined construction platform maximum temperature, for example, for a predetermined period of time after completion of the at least one component before the component is unpacked. After unpacking, the component may be further cured as needed.

[0083] For example, a 3D printer may comprise a construction platform (for example, adjustable in height) provided with a heating device, a coater for applying a layer of loose particulate material to the construction platform, a print head for outputting a liquid treatment agent onto a partial area of a last applied layer of loose particulate material, and a control device configured to perform the above-described method.

[0084] For example, as shown in FIG. 6, the 3D printer may comprise at least a first temperature sensor for sensing a surface temperature of the last applied layer of loose particulate material T.sub.OF and/or at least a second temperature sensor for sensing a temperature of the construction platform T.sub.BP. The first and/or second temperature sensor may, for example, be configured as described above.

[0085] The construction platform may, for example, be configured to be fluid-impermeable. The heating device may, for example, be arranged on and/or in the construction platform.