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CN-122029028-A - Method for monitoring a manufacturing process of a 3D printer comprising a magnetically levitated printing bed

CN122029028ACN 122029028 ACN122029028 ACN 122029028ACN-122029028-A

Abstract

In various embodiments, a method for quality management of a printing process of a 3D object (402) comprising a plurality of layers (404, 406) is provided. The method comprises a magnetically levitated print bed (408) onto which printing material is deposited to manufacture the 3D object, the method comprising determining the weight of printing material that has been deposited onto the print bed so far from the forces acting on the levitated print bed and comparing the calculated weight with the measured weight in a continuous manner or at discrete time intervals. The method may be used to determine whether at least a subsection of a layer of the printed 3D object meets an expected quality criterion based on the comparison.

Inventors

  • M. P. Chaya
  • N. Carney
  • A. SCHNEIDER

Assignees

  • 贝拉塞诺有限公司

Dates

Publication Date
20260512
Application Date
20240905
Priority Date
20230905

Claims (11)

  1. 1. A method for monitoring a manufacturing process of a 3D printer, wherein the 3D printer comprises a floating print bed onto which printing material is deposited to manufacture a 3D object, the method comprising: Determining a parameter indicative of a force acting on the levitation print bed to maintain levitation thereof; determining the weight of the printing material that has been deposited onto the print bed so far from the force acting on the suspended print bed; the determined weight of the printing material that has been deposited to date on the print bed is compared with the calculated weight of the printing material that has been deposited to date on the print bed.
  2. 2. The method of claim 1, wherein the print bed is a magnetic levitation print bed.
  3. 3. The method of claim 1 or 2, wherein the 3D printer comprises an extruder that is movable independently of the suspended print bed along a vertical axis perpendicular to the suspended print bed.
  4. 4. A method according to any one of claims 1 to 3, wherein the suspended print bed comprises a permanent magnet and is controlled by an electromagnetic field generated by a coil of a magnetically levitated platform.
  5. 5. The method according to any one of claims 1 to 4, wherein the weight of the printing material that has been deposited onto the print bed so far is calculated by dividing the force acting on the print bed by the acceleration of gravity.
  6. 6. The method of any of claims 1-5, wherein the weight of the printing material that has been deposited onto the print bed is determined multiple times during the manufacturing process.
  7. 7. The method of any of claims 1-6, wherein the weight of the printing material that has been deposited onto the print bed is continuously determined during the manufacturing process.
  8. 8. The method of any one of claims 1 to 8, further comprising: At least one parameter of the printing process is adjusted when a deviation between the measured weight and the calculated weight of the printing material that has been deposited onto the print bed exceeds a first predetermined threshold.
  9. 9. The method of claim 8, wherein at least one parameter of the printing process is adjusted when the deviation between the measured weight of the printing material that has been deposited onto the print bed and the calculated weight exceeds a first predetermined threshold a predetermined number of times.
  10. 10. The method of any one of claims 1 to 9, further comprising: the manufacturing process is aborted when a deviation between the measured weight and the calculated weight of the printing material that has been deposited onto the print bed exceeds a second predetermined threshold.
  11. 11. The method according to any one of claims 1 to 10, wherein the weight of the printing material that has been deposited onto the print bed is obtained by means of a calibration curve obtained in advance, which correlates a reference weight with a corresponding force acting on the suspended print bed.

Description

Method for monitoring a manufacturing process of a 3D printer comprising a magnetically levitated printing bed Cross Reference to Related Applications The present application claims the benefit of priority from european patent application serial No. 23195423.1 filed on 5, 9, 2023, which is incorporated herein by reference in its entirety for all purposes. Technical Field The present invention relates to the field of additive manufacturing, in particular to a method for monitoring a manufacturing process of a 3D printer comprising a magnetically levitated print bed. Background Additive Manufacturing (AM), more commonly referred to as 3D printing, refers to a set of techniques that are capable of manufacturing any kind of object or physical component by characteristically adding material layer by layer on a print bed (also referred to as a build platform). This process is essentially different from conventional machining, which is accomplished by drilling, milling, etc. minus the piece of material. The 3D printer creates the 3D object, typically through an additive process. The 3D model is first designed using Computer Aided Design (CAD) software, and then sliced into multiple layers by slicing software (software engines). The object is then built layer by moving the extrusion nozzle of the 3D printer in unison in the plane containing the layer (e.g., x and y directions). Once the layer is completed, the extrusion nozzle (or a plane containing the completed layer) is moved vertically (e.g., in the z-direction) to begin the extrusion process for the next layer. The printing material is continuously generated layer by layer until the object is completely built up from bottom to top (from the perspective of the 3D printer). The motion and three-dimensional movement of the extrusion nozzle that determines the extrusion position of the printed material is specified and controlled by a Computer Numerical Control (CNC) programming language. Typically, in consumer and industrial grade 3D printers, G codes are used to achieve this. It goes without saying that in order to obtain a 3D printed object with the required mechanical properties, each printed layer has to be manufactured according to the design. That is, the outermost portion of the layer and its filling pattern must be printed with high precision according to the design pattern. Based on the design pattern of the 3D object to be printed, the 3D printer software can determine how much printing material should be extruded in a given layer and in a given subsection of that layer. Variations in the output of the extruder nozzle can result in defects in the printed 3D object that may not be detected. For example, if the printed material of a particular filled region is too much or too little (corresponding to the case of over-extrusion and under-extrusion, respectively) compared to the actual design, such variations may not be visible from the outside when inspecting the final product. In the case of under-extrusion, the thickness or diameter of the extruded material is too small, and in extreme cases gaps between adjacent extruded sections may be seen when inspecting the layer. In the case of over-extrusion, the 3D printer extrudes more material than expected (e.g., according to software calculations). When over-extruded or under-extruded portions are disposed in the outer shell of the layer, the size/appearance of the manufactured object may be affected. Deviations in the amount of extruded material, especially in the filling pattern, are undesirable because they may lead to mechanically stronger or weaker parts inside the 3D printed item, possibly changing its mechanical properties. Variations in the amount of extruded material can be caused by a variety of factors, such as incorrect nozzle height, incorrect printing temperature, and the presence of dust and dirt in the extrudate, which can cause nozzle portions to clog or block. For example, when the temperature of the extruder is too low, the printing material may not be completely melted and begin to adhere to the inner surface of the extruder nozzle. Considering that in the worst case the inherent inaccuracy (inaccuracy) of thermostats is up to 10%, it can be seen that avoiding or at least reliably detecting overextrusion and underextrusion is a rather challenging task, which is of great significance in 3D printing. The interaction between the magnetic fields of the mover and stator modules levitates the printing platform over the stator unit. By carefully controlling and varying the strength and direction of the magnetic field, a stable levitation and frictionless movement of the printing platform over the stator module can be achieved. In order to achieve stability and precise control, the suspension mechanism is equipped with a complex control system. The control system monitors the position and orientation of the platform using magnetic field sensors (e.g., sensors strategically placed across the struct