Methods and devices for counteracting stresses during 3D printing

1. A method of 3D printing an object, the method comprising:

depositing build material in a predetermined pattern to form a first layer of a 3D printed object; and

depositing build material in a predetermined pattern to form a first layer of a skirt in contact with the 3D printed object,

wherein depositing build material to form the first layer of the skirt comprises 3D printing a first layer of a sidewalk that substantially surrounds at least a portion of a perimeter of the 3D printed object and 3D printing a first layer of a perforated interface between the sidewalk and the perimeter of the skirt, and

wherein depositing build material in a predetermined pattern to form the first layer of the 3D printed object is carried out prior to depositing build material in a predetermined pattern to form the first layer of the skirt.

2. The method of claim 1 further comprising depositing build material in a predetermined pattern to form a number of additional layers of the skirt beyond the first layer,

wherein the 3D printed object defines a geometry; and

wherein the number of additional layers of the skirt deposited is determined by at least one of the geometry and build material of the 3D printed object.

3. The method of claim 1 , wherein:

the 3D printed object defines a geometry; and

a width of the sidewalk is determined based upon at least one of the geometry and build material of the 3D printed object.

4. The method of claim 1 , wherein depositing build material in a predetermined pattern to form the first layer of the skirt comprises:

first, depositing build material to form a perimeter of the sidewalk of the skirt; and

second, depositing build material to form a plurality of contacts to define the perforated interface between the sidewalk and the perimeter of the 3D printed object.

5. A method of 3D printing an object, the method comprising:

depositing build material in a predetermined pattern to form a first layer of a 3D printed object; and

depositing build material in a predetermined pattern to form a first layer of a skirt in contact with the 3D printed object,

wherein depositing build material to form the first layer of the skirt comprises 3D printing a first layer of a sidewalk that substantially surrounds at least a portion of a perimeter of the 3D printed object and 3D printing a first layer of a perforated interface between the sidewalk and the perimeter of the skirt, and

wherein depositing build material in a predetermined pattern to form the first layer of the skirt comprises:

depositing build material to form the sidewalk of the skirt; and

concurrent with depositing build material to form the sidewalk, depositing build material to form a plurality of connectors and a plurality of gaps along the perimeter of the 3D printed object.

6. The method of claim 5 , wherein a connector-to-gap ratio is less than or equal to 2:1.

7. The method of claim 6 , wherein the connector-to-gap ratio is less than or equal to 1:1.

8. The method of claim 6 , wherein the connector-to-gap ratio is less than or equal to 0.5:1.

9. The method of claim 6 , wherein the connector-to-gap ratio is less than or equal to 0.25:1.

10. The method of claim 5 , wherein:

at least two of the connectors have sides that define an angle of 90 degrees or less relative to the perimeter of the 3D printed object adjacent the respective connector.

11. The method of claim 1 , wherein:

the sidewalk comprises a sidewalk border; and

the sidewalk border intermittently contacts the perimeter of the 3D printed object to define the perforated interface.

12. The method of claim 1 , wherein 3D printing the first layer of the sidewalk comprises defining a tear-off starter in the first layer of the sidewalk.

13. The method of claim 1 further comprising separating the sidewalk from the 3D printed object by pulling the sidewalk away from the 3D printed object in a direction that causes the perforated interface to separate from the 3D printed object.

14. The method of claim 13 , wherein:

3D printing the first layer of the sidewalk comprises defining a tear-off starter in the first layer of the sidewalk; and

separating the sidewalk from the 3D printed object by pulling the sidewalk away from the 3D printed object comprises applying a force to the tear-off starter.

15. The method of claim 1 , wherein:

depositing build material to form the first layer of the sidewalk defines a fill pattern; and

the fill pattern contacts the perimeter of the 3D printed object to define the perforated interface.

16. The method of claim 15 , wherein the fill pattern defines at least one of a perpendicular hatch pattern, a diagonal hatch pattern, a perpendicular line pattern, an obtuse angle pattern, and an acute angle pattern.

17. The method of claim 15 , wherein:

the fill pattern defined by depositing build material to form the first layer of the sidewalk is a first fill pattern;

depositing build material to form the first layer of the 3D printed object defines a second fill pattern; and

the first fill pattern differs from the second fill pattern.

18. A method of 3D printing an object, the method comprising:

first, depositing build material to define at least a first layer of a fill portion of a 3D printed object;

second, depositing build material to define at least a first layer of a fill portion of a sidewalk substantially surrounding at least a portion of the 3D printed object;

third, depositing at least a first layer of a border portion of the 3D printed object; and

fourth, depositing at least a first layer of a border portion of the sidewalk,

wherein a perforated interface is defined between the sidewalk and the border of the 3D printed object.