Automatic adjustment of a heater control in an additive manufacturing device

Patent metadata

Field	Value
Publication number	US-10953601-B2
Application number	US-201715622099-A
Country	US
Kind code	B2
Filing date	Jun 14, 2017
Priority date	Jun 23, 2016
Publication date	Mar 23, 2021
Grant date	Mar 23, 2021

Abstract

A device for an adjustment of a heater control in an additive manufacturing device, in which a heater control regulates the heating of an applied building material layer by means of a heating device ( 17 ) up to a work temperature (T A ) comprises:
a nominal parameter provision unit ( 201 ) designed such that it provides at least one nominal parameter value, meaning the setpoint of a controlled variable and/or its change with time and/or the setpoint of a heater parameter and/or its change with time, an actual parameter detection unit ( 202 ) designed such that it is able to detect for at least one of the nominal parameter values the corresponding actual parameter value in the heater control or in the additive manufacturing device, wherein an actual parameter value is the actual value of a controlled variable and/or the actual value of its change with time and/or the actual value of a heater parameter and/or the actual value of its change with time, and a control change unit ( 203 ) that automatically changes at least one control parameter value, if a predefined difference between the nominal parameter value and its corresponding actual parameter value is exceeded.

First claim

The invention claimed is:

1. A method for adjusting a heater control in an additive manufacturing apparatus that builds one or more objects at a time through a layer-wise application of building material, each new layer being on top of and solidified to a previous underlying layer, with a plurality of building material layers corresponding to cross-sections of the one or more objects, the building material being melted by heat producing radiation, and the building material thereafter solidifying, the method comprising:
providing a heater device that provides heat to the building material;
regulating the heat provided by the heater device with the heater control, a functioning of the heater control being defined by at least one control parameter, the regulating being effected by:
providing at least one nominal parameter value selected from one or more of a setpoint of a controlled variable of the heater control, the setpoint of a change of the controlled variable with time, the setpoint of a heater parameter, and/or the setpoint of a change in the heater parameter with time, the at least one nominal parameter value being predetermined and stored in and/or input into the heater device;
heating the build material with the heater device during a heating process;
detecting at least one actual parameter value corresponding to the at least one nominal parameter value during the heating process, the actual parameter value being one or more of an actual value of the controlled variable, an actual value of a change of the controlled variable with time, an actual value of the heater parameter, and/or an actual value of a change in the heater parameter with time;
comparing the nominal parameter value to the actual parameter value;
determining that the actual parameter value falls outside a deviation from the nominal parameter value; and
automatically changing the at least one control parameter to bring the temperature of the building material layer being solidified within a control region Tactual+−deltaT, where Tactual is the working temperature, the at least one control parameter being a maximum heating power of the heater device, a maximum or minimum change of the heating power of the heater device with time, the deviation, and a control type of a PID controller.

2. The method according to claim 1 , wherein the at least one control parameter is the control type of the PID controller and includes a P gain, a reset time or a derivative time of a proportional, integral or derivative term of the heater control.

3. The method according to claim 1 , wherein the at least one nominal parameter is at least one of the following quantities:
a work temperature, a maximum and/or minimum change of a temperature of the building material with time, a maximum duration for the heating of the building material up to the work temperature from a start of the application of a new building material layer, and a control accuracy.

4. The method according to claim 1 , further comprising detecting a time needed for heating a newly applied building material layer up to a work temperature and automatically changing the at least one control parameter if a predetermined maximum heating-up time is exceeded.

5. The method according to claim 1 , wherein a fuzzy control is used for changing the at least one control parameter.

6. The method according to claim 1 , wherein a neural network and/or an evolutionary algorithm are/is used for changing the at least one control parameter, wherein neural network and/or evolutionary algorithm access actual parameter values are previously detected.

7. The method according to claim 1 , further comprising applying and solidifying n layers, wherein n is a natural number smaller or equal to a maximum number of layers applied during the manufacturing.

8. The method according to claim 1 , further comprising determining the functioning of the heater control by carrying out the method as a test method before the application and solidification of a first layer for a manufacture of a number of the objects and changing the at least one control parameter based on the test method.

9. A computer program that is able to be loaded into a control unit and/or an additive manufacturing device and has program code means for carrying out all steps of the method according to claim 1 when the computer program is executed in the control unit and/or the additive manufacturing device.

10. The method according to claim 1 , wherein in the additive manufacturing device a number of objects can be manufactured by a layer-wise application of powder layers.

Assignees

• Eos Gmbh Electro Optical Systems

Inventors

• Fruth Albert
• Keller Peter
• Schmidtner Markus

Classifications

• B29C64/295

  Heating elements · CPC title

• B29C64/153 Primary

  using layers of powder being selectively joined, e.g. by selective laser sintering or melting · CPC title

• B29C64/393

  for controlling or regulating additive manufacturing processes · CPC title

• B33Y50/02

  for controlling or regulating additive manufacturing processes · CPC title

• B33Y10/00

  Processes of additive manufacturing · CPC title