Extrusion-based additive manufacturing: method and 3D printing system

1 . A method for enabling an extrusion-based additive manufacturing (AM) three-dimensional (3D) printing system to handle individual 3D parts of a print job comprising at least two 3D parts, the method comprising the steps of:

providing the print job that provides digital 3D representations of the at least two 3D parts;

slicing the print job to generate a set of slices for the digital 3D representations of the at least two 3D parts, each slice of the set of slices comprising geometrical data defining respective boundaries of a respective layer of AM feedstock material that is to be deposited from a nozzle of a printing head on one of a build surface and a previously deposited layer of AM feedstock material to print each 3D part taking into account said respective boundaries;

generating for each 3D part a respective individual set of geometrical data taking into account said geometrical data provided by each slice of the set of slices, wherein each individual set of geometrical data comprises geometrical data defining the respective boundaries of the respective layers of AM feedstock material that are to be taken into account for printing the respective 3D part;

sending the sliced print job to an AM 3D printing system;

optimizing the print procedure for the respective AM 3D printing system for each 3D part individually by generating for each 3D part the respective individual set of geometrical data taking into account said geometrical data provided by each slice of the set of slices and taking into account parameters of the respective AM 3D printing system; and

generating an individual set of control instructions for each 3D part based on the individual set of geometrical data.

2 . The method according to claim 1 , comprising the steps of adapting sliced object data to parameters relating to an AM 3D printing system based on decisions made based on run time data, including data relating to the respective printer, that was not available at the time of slicing.

3 . The method according to claim 1 , wherein generating for each 3D part a respective individual set of geometrical data taking into account said geometrical data provided by each slice of the set of slices comprises:

providing the geometrical data provided by each slice of the set of slices with custom commands to group for each 3D part the respective geometrical data defining the respective boundaries of the respective layers of AM feedstock material that are to be deposited, thereby generating for each 3D part the respective individual set of geometrical data.

4 . The method according to claim 1 , wherein generating for each 3D part a respective individual set of geometrical data taking into account said geometrical data provided by each slice of the set of slices comprises:

reconstructing each volume that is to be printed by taking into account the geometrical data provided by each slice of the set of slices and a predefined standard layer thickness with which the respective layers of AM feedstock material are to be deposited;

identifying 3D parts by comparing each reconstructed volume with each volume of each 3D part as defined by the respective digital 3D representations of the respective 3 D parts; and

grouping for each slice of the set of slices the respective geometrical data for each identified 3D part, thereby generating for each 3D part the respective individual set of geometrical data.

5 . The method according to claim 1 , comprising:

determining for each 3D part a respective individual footprint based on the respective geometrical data for a respective first layer of AM feedstock material that is to be deposited in direct contact with the build surface provided by the respective individual set of geometrical data for the respective 3D part, each respective individual footprint being an area that is enclosed by respective boundaries of the respective first layer of AM feedstock material;

generating an individual set of control instructions for each 3D part by taking into account the respective individual set of geometrical data for the respective 3D part, wherein each individual set of control instructions enables the AM 3D system to individually control fabrication of each 3D part; and

printing each 3D part on a respective individual print area of the build surface taking into account the respective individual set of control instructions for the respective 3D part, wherein the respective individual print area is equal to the respective individual footprint of the respective 3D part.

6 . The method according to claim 5 , wherein printing each 3D part on a respective individual print area of the build surface taking into account the respective individual set of control instructions for the respective 3D part further comprises:

detecting an error associated with at least one deposited layer of AM feedstock material of a respective 3D part of the at least two 3D parts, and labelling the respective 3D part as a rejected 3D part;

individually terminating printing of the rejected 3D part while continuing printing non-rejected 3D parts of the at least two 3D parts until all layers of AM feedstock have been deposited for the respective non-rejected 3D part or all 3D parts have been rejected.

7 . The method according to claim 6 , wherein for each individually rejected 3D part a respective waiting time is generated that has a duration that is equal to a respective deposition time that would have been required for depositing the respective next layer of AM feedstock material for the respective individually rejected 3D part, wherein the respective waiting time for each individually rejected 3D part is taken into account when depositing the respective next layer of AM feedstock material for each respective non-rejected 3D part of the at least two 3D parts to maintain validity of a thermal simulation result that has been obtained by performing a thermal simulation taking into account the respective individual set of control instructions for each 3D part prior to starting printing each 3D part on a respective individual print area of the build surface.

8 . The method according to claim 5 , wherein printing each 3D part on a respective individual print area of the build surface taking into account the respective individual set of control instructions for the respective 3D part further comprises:

depositing the respective first layer of AM feedstock material in contact with the build surface of the respective individual print area of the respective 3D part and depositing respective next layers of AM feedstock material on top of each other starting from the respective first layer, the respective next layers of AM feedstock material having identical characteristics whereas the respective first layer of AM feedstock material has at least one characteristic that distinguishes the respective first layer from the respective next layers thereby enabling, after printing of the respective 3D part has been terminated, an improved removability of the respective first layer from the respective next layers of AM feedstock material without causing delamination of the respective next layers from each other.

9 . The method according to claim 1 , wherein generating the individual set of control instructions for each 3D part comprises:

transforming a coordinate system of the respective 3D part to align a bottom surface of the respective 3D part with the build surface of the 3D printing system;

determining distances between the bottom surface of the respective 3D part and the build surface at predefined locations across the respective individual print area onto which the respective 3D part is to be printed for determining a distance distribution over the entire respective individual print area;

determining a minimum distance, d min , and a maximum distance, d max , of the determined distance distribution;

generating the respective individual set of control instructions for the respective 3D part using the determined distance distribution if d min and d max satisfy a condition t min ≤d min <d max ≤t max , wherein t min is a predefined minimum thickness and t max is a predefined maximum thickness of the respective first layer of AM feedstock material, wherein after having been deposited, the respective first layer of AM feedstock material provides a substantially planar top surface on which a next layer of AM feedstock material is printable.

10 . The method according to claim 9 , wherein the individual set of control instructions for the respective 3D part is generated after performing an individual coordinate transformation of the respective 3D part in order to allow d min and d max to satisfy the condition t min ≤d min <d max ≤t max .

11 . The method according to claim 10 , wherein the individual coordinate transformation of the respective 3D part involves at least one of:

translation along the z-axis of the coordinate system of the respective 3D part;

rotation Rx around the x-axis of the coordinate system of the respective 3D part; and

rotation Ry around the y-axis of the coordinate system of the respective 3D part.

12 . The method according to claim 11 , wherein determining the individual coordinate transformation for the respective 3D part further comprises taking into account a determined non-straightness of at least one of an x-axis arrangement, a y-axis arrangement and a z-axis arrangement of the AM 3D printing system.

13 . The method according to claim 9 , wherein the distances between the bottom surface of the respective 3D part and the build surface at predefined locations across the respective individual print area are determined using results obtained by at least one of a contactless measurement technique and a measurement technique that involves a physical contact between the build surface and at least one of:

a probing arrangement that is associated with the printing head; and

the nozzle of the printing head.

14 . The method according to claim 9 , wherein the predefined minimum thickness, t min , of the respective first layer of AM feedstock material is equal to 50% of a predefined standard layer thickness with which respective other layers of AM feedstock material than the respective first layer of AM feedstock material are to be deposited, and the predefined maximum thickness, t max , of the respective first layer of AM feedstock material is equal to 150% of said predefined standard layer thickness.

15 . The method according to claim 9 , wherein prior to printing each 3D part on a respective individual print area of the build surface, a respective 3D part of the at least two 3D parts is individually rejected upon determining that no respective individual set of control instructions has been generated for the respective 3D part thereby avoiding starting printing of the respective 3D part on the respective individual print area.

16 . The method of claim 1 , including the steps of:

the AM 3D printing system distinguishing the at least two individual 3D parts in the print job; and at least one of

the step of slicing the print job to generate a set of slices for the digital 3D representations of the at least two 3D parts including adding additional control instructions certifying which instructions belong to which 3D part; or

simulating the build of the print job in the AM 3D printing system, and then reconstructing which bodies do not touch during printing, meaning these eventually will become the individual 3D parts.

17 . An extrusion-based additive manufacturing (AM) three-dimensional (3D) printing system that is adapted to handle individual 3D parts of a print job comprising at least two 3D parts, the extrusion-based AM 3D printing system comprising a processing unit that is provided with computer instructions which when executed in the processing unit enable the extrusion-based AM 3D printing system to perform the method according to claim 1 .

18 . The method according to claim 1 , comprising the steps of adapting sliced object data to parameters relating to an AM 3D printing system and making decisions based on run time data, including data relating to the respective printer, that was not available at the time of slicing;

wherein generating for each 3D part a respective individual set of geometrical data taking into account said geometrical data provided by each slice of the set of slices comprises:

providing the geometrical data provided by each slice of the set of slices with custom commands to group for each 3D part the respective geometrical data defining the respective boundaries of the respective layers of AM feedstock material that are to be deposited, thereby generating for each 3D part the respective individual set of geometrical data;

wherein generating for each 3D part a respective individual set of geometrical data taking into account said geometrical data provided by each slice of the set of slices comprises:

reconstructing each volume that is to be printed by taking into account the geometrical data provided by each slice of the set of slices and a predefined standard layer thickness with which the respective layers of AM feedstock material are to be deposited;

identifying 3D parts by comparing each reconstructed volume with each volume of each 3D part as defined by the respective digital 3D representations of the respective 3D parts; and

grouping for each slice of the set of slices the respective geometrical data for each identified 3D part, thereby generating for each 3D part the respective individual set of geometrical data;

additionally comprising the steps of:

determining for each 3D part a respective individual footprint based on the respective geometrical data for a respective first layer of AM feedstock material that is to be deposited in direct contact with the build surface provided by the respective individual set of geometrical data for the respective 3D part, each respective individual footprint being an area that is enclosed by respective boundaries of the respective first layer of AM feedstock material;

generating an individual set of control instructions for each 3D part by taking into account the respective individual set of geometrical data for the respective 3D part, wherein each individual set of control instructions enables the AM 3D system to individually control fabrication of each 3D part; and

printing each 3D part on a respective individual print area of the build surface taking into account the respective individual set of control instructions for the respective 3D part, wherein the respective individual print area is equal to the respective individual footprint of the respective 3D part; and

wherein generating the individual set of control instructions for each 3D part comprises:

transforming a coordinate system of the respective 3D part to align a bottom surface of the respective 3D part with the build surface of the 3D printing system;

determining distances between the bottom surface of the respective 3D part and the build surface at predefined locations across the respective individual print area onto which the respective 3D part is to be printed for determining a distance distribution over the entire respective individual print area;

determining a minimum distance, d min , and a maximum distance, d max , of the determined distance distribution; and

generating the respective individual set of control instructions for the respective 3D part using the determined distance distribution if d min and d max satisfy a condition t min ≤d min <d max ≤t max , wherein t min is a predefined minimum thickness and t max is a predefined maximum thickness of the respective first layer of AM feedstock material, wherein after having been deposited, the respective first layer of AM feedstock material provides a substantially planar top surface on which a next layer of AM feedstock material is printable.

19 . The method according to claim 18 , wherein the individual set of control instructions for the respective 3D part is generated after performing an individual coordinate transformation of the respective 3D part in order to allow d min and d max to satisfy the condition t min ≤d min <d max ≤t max ;

wherein the individual coordinate transformation of the respective 3D part involves at least one of:

translation along the z-axis of the coordinate system of the respective 3D part;

rotation Rx around the x-axis of the coordinate system of the respective 3D part; and

rotation Ry around the y-axis of the coordinate system of the respective 3D part;

wherein determining the individual coordinate transformation for the respective 3D part further comprises taking into account a determined non-straightness of at least one of an x-axis arrangement, a y-axis arrangement and a z-axis arrangement of the AM 3D printing system;

wherein the distances between the bottom surface of the respective 3D part and the build surface at predefined locations across the respective individual print area are determined using results obtained by at least one of a contactless measurement technique and a measurement technique that involves a physical contact between the build surface and at least one of:

a probing arrangement that is associated with the printing head; and

the nozzle of the printing head;

wherein the predefined minimum thickness, t min , of the respective first layer of AM feedstock material is equal to 50% of a predefined standard layer thickness with which respective other layers of AM feedstock material than the respective first layer of AM feedstock material are to be deposited, and the predefined maximum thickness, t max , of the respective first layer of AM feedstock material is equal to 150% of said predefined standard layer thickness;

wherein prior to printing each 3D part on a respective individual print area of the build surface, a respective 3D part of the at least two 3D parts is individually rejected upon determining that no respective individual set of control instructions has been generated for the respective 3D part thereby avoiding starting printing of the respective 3D part on the respective individual print area;

wherein printing each 3D part on a respective individual print area of the build surface taking into account the respective individual set of control instructions for the respective 3D part further comprises:

detecting an error associated with at least one deposited layer of AM feedstock material of a respective 3D part of the at least two 3D parts, and labelling the respective 3D part as a rejected 3D part;

individually terminating printing of the rejected 3D part while continuing printing non-rejected 3D parts of the at least two 3D parts until all layers of AM feedstock have been deposited for the respective non-rejected 3D part or all 3D parts have been rejected;

wherein for each individually rejected 3D part a respective waiting time is generated that has a duration that is equal to a respective deposition time that would have been required for depositing the respective next layer of AM feedstock material for the respective individually rejected 3D part, wherein the respective waiting time for each individually rejected 3D part is taken into account when depositing the respective next layer of AM feedstock material for each respective non-rejected 3D part of the at least two 3D parts to maintain validity of a thermal simulation result that has been obtained by performing a thermal simulation taking into account the respective individual set of control instructions for each 3D part prior to starting printing each 3D part on a respective individual print area of the build surface; and

wherein printing each 3D part on a respective individual print area of the build surface taking into account the respective individual set of control instructions for the respective 3D part further comprises:

depositing the respective first layer of AM feedstock material in contact with the build surface of the respective individual print area of the respective 3D part and depositing respective next layers of AM feedstock material on top of each other starting from the respective first layer, the respective next layers of AM feedstock material having identical characteristics whereas the respective first layer of AM feedstock material has at least one characteristic that distinguishes the respective first layer from the respective next layers thereby enabling, after printing of the respective 3D part has been terminated, an improved removability of the respective first layer from the respective next layers of AM feedstock material without causing delamination of the respective next layers from each other.

20 . A method for enabling an extrusion-based additive manufacturing (AM) three-dimensional (3D) printing system to handle individual 3D parts of a print job comprising at least two 3D parts, the method comprising the steps of:

providing the print job that provides digital 3D representations of the at least two 3D parts;

slicing the print job to generate a set of slices for the digital 3D representations of the at least two 3D parts, each slice of the set of slices comprising geometrical data defining respective boundaries of a respective layer of AM feedstock material that is to be deposited from a nozzle of a printing head on one of a build surface and a previously deposited layer of AM feedstock material to print each 3D part taking into account said respective boundaries;

generating for each 3D part a respective individual set of geometrical data taking into account said geometrical data provided by each slice of the set of slices, wherein each individual set of geometrical data comprises geometrical data defining the respective boundaries of the respective layers of AM feedstock material that are to be taken into account for printing the respective 3D part; and

adapting sliced object data to parameters relating to an AM 3D printing system based on decisions made based on run time data, including data relating to the respective printer, that was not available at the time of slicing.