Methods for additively manufacturing composite parts
A method of additively manufacturing a composite part is disclosed. The method comprises pushing a continuous flexible line through a delivery guide. The continuous flexible line comprises a non-resin component and a thermosetting-epoxy-resin component that is partially cured. The method also comprises depositing, via the delivery guide, a segment of the continuous flexible line along a print path. The method further comprises maintaining the thermosetting-epoxy-resin component of at least the continuous flexible line being pushed through the delivery guide below a threshold temperature prior to depositing the segment of the continuous flexible line along the print path.
1. A method of additively manufacturing a composite part, the method comprising:
pushing a continuous flexible line through a delivery guide using a feed mechanism, wherein the continuous flexible line comprises a non-resin component and a thermosetting-epoxy-resin component that is partially cured, and wherein the feed mechanism comprises opposing rollers and a scraper in contact with at least one of the opposing rollers;
depositing, via the delivery guide, a segment of the continuous flexible line along a print path;
removing, using the scraper, residue of the thermosetting-epoxy-resin component, produced by the engagement between the opposing rollers and the continuous flexible line as the opposing rollers rotate to selectively translate the continuous flexible line to push the continuous flexible line through the delivery guide; and
collecting, into a collection reservoir, the residue of the thermosetting-epoxy-resin component, removed by the scraper.
2. The method according to claim 1 ,
wherein:
the delivery guide comprises a line passage through which the continuous flexible line is delivered to the print path;
the line passage of the delivery guide has an inlet;
the feed mechanism is configured to push the continuous flexible line through the line passage;
the opposing rollers having have respective rotational axes;
the delivery guide further comprises a first end portion, a second end portion, and a junction between the first end portion and the second end portion;
the first end portion is shaped to be complementary to one of the opposing rollers and the second end portion is shaped to be complementary to another of the opposing rollers; and
a shortest distance (D) between the junction and a plane, containing the respective rotational axes of the opposing rollers, is less than a radius of a smallest one of the opposing rollers.
3. The method according to claim 2 , wherein the junction comprises an edge.
4. The method according to claim 2 , wherein the threshold temperature is no greater than 20° C.
5. The method according to claim 1 , wherein the non-resin component comprises one or more of a fiber, a carbon fiber, a glass fiber, a synthetic organic fiber, an aramid fiber, a natural fiber, a wood fiber, a boron fiber, a silicon-carbide fiber, an optical fiber, a fiber bundle, a fiber tow, a fiber weave, a wire, a metal wire, a conductive wire, or a wire bundle.
6. The method according to claim 1 , wherein depositing the segment of the continuous flexible line along the print path comprises layering the continuous flexible line against itself or a previously deposited segment to additively manufacture the composite part.
7. The method according to claim 1 , wherein depositing the segment of the continuous flexible line along the print path comprises depositing the continuous flexible line in a predetermined pattern to selectively control one or more physical characteristics of the composite part.
8. The method according to claim 7 , wherein the physical characteristics include at least one of strength, stiffness, flexibility, ductility, or hardness.
9. The method according to claim 1 , further comprising delivering a predetermined or actively determined amount of curing energy at least to a portion of the segment of the continuous flexible line at a controlled rate while advancing the continuous flexible line toward the print path and after the segment of the continuous flexible line is deposited along the print path to at least partially cure at least the portion of the segment of the continuous flexible line.
10. The method according to claim 9 , wherein delivering the predetermined or actively determined amount of the curing energy at least to the portion of the segment of the continuous flexible line at the controlled rate comprises partially curing a first layer of the segment of the continuous flexible line as the first layer is being deposited and further curing the first layer as a second layer is being deposited against the first layer.
11. The method according to claim 9 , wherein delivering the predetermined or actively determined amount of the curing energy at least to the portion of the segment of the continuous flexible line at the controlled rate comprises curing less than an entirety of the composite part.
12. The method according to claim 9 , wherein delivering the predetermined or actively determined amount of the curing energy at least to the portion of the segment of the continuous flexible line at the controlled rate comprises selectively varying at least one of a delivery rate, a delivery duration, or a temperature of the curing energy to impart varying physical characteristics to the composite part.
13. The method according to claim 12 , wherein the varying physical characteristics include at least one of strength, stiffness, flexibility, ductility, or hardness.
14. The method according to claim 9 , further comprising, simultaneously with delivering the predetermined or actively determined amount of the curing energy at least to the portion of the segment of the continuous flexible line at the controlled rate, at least partially protecting at least the portion of the segment of the continuous flexible line from oxidation after the segment exits the delivery guide.
15. The method according to claim 14 , wherein at least the portion of the segment of the continuous flexible line is at least partially protected from the oxidation with a shielding gas.
16. The method according to claim 9 , further comprising restrictively curing at least a portion of the composite part.
17. The method according to claim 16 , wherein the portion of the composite part is restrictively cured to facilitate subsequent processing of the portion of the composite part.
18. The method according to claim 1 , further comprising, simultaneously with depositing the segment of the continuous flexible line along the print path, compacting at least a section of the segment of the continuous flexible line after the segment of the continuous flexible line is deposited along the print path.
19. The method according to claim 18 , wherein compacting at least the section of the segment of the continuous flexible line after the segment of the continuous flexible line is deposited along the print path comprises imparting a desired cross-sectional shape to the segment of the continuous flexible line.
20. The method according to claim 1 , further comprising, simultaneously with depositing the segment of the continuous flexible line along the print path, roughening at least a section of the segment of the continuous flexible line after the segment of the continuous flexible line is deposited along the print path.
21. The method according to claim 20 , further comprising, simultaneously with roughening at least the section of the segment of the continuous flexible line, collecting debris resulting from roughening at least the section of the segment of the continuous flexible line.
22. The method according to claim 20 , further comprising, simultaneously with roughening at least the section of the segment of the continuous flexible line, dispersing debris resulting from roughening at least the section of the segment of the continuous flexible line.
23. The method according to claim 1 , further comprising selectively cutting the continuous flexible line, wherein the continuous flexible line is selectively cut simultaneously with depositing the segment of the continuous flexible line along the print path.
24. The method according to claim 1 , further comprising, simultaneously with depositing the segment of the continuous flexible line along the print path, detecting defects in the composite part.
25. The method according to claim 1 , wherein depositing the segment of the continuous flexible line along the print path comprises depositing at least a portion of the segment of the continuous flexible line over a sacrificial layer.
26. The method according to claim 25 , further comprising removing the sacrificial layer to form the composite part.
27. The method according to claim 1 , wherein:
the continuous flexible line is a first continuous flexible line,
the segment of the continuous flexible line is a first segment of the first continuous flexible line,
the method further comprises depositing a second segment of a second continuous flexible line along the print path, and
the second continuous flexible line comprises at least one component that differs from at least one component of the first continuous flexible line.
28. The method according to claim 1 , further comprising:
maintaining, by a cooling system, the thermosetting-epoxy-resin component of at least the continuous flexible line being pushed through the delivery guide below a threshold temperature prior to depositing the segment of the continuous flexible line along the print path; and
wherein:
the cooling system comprises a coolant line, through which a coolant is circulated;
the cooling system further comprises an insulated sleeve, through which the continuous flexible line travels from an insulated store to the delivery guide; and
the insulated sleeve is thermally coupled with the coolant line to internally cool the insulated sleeve.
29. The method according to claim 1 , wherein:
at least one of the opposing rollers comprises a circumferential channel that contacts the continuous flexible line, and
the scraper comprises a projection that removes from the circumferential channel the residue of the thermosetting-epoxy-resin component, produced by the engagement between the circumferential channel and the continuous flexible line as the opposing rollers rotate to selectively translate the continuous flexible line to push the continuous flexible line through the delivery guide.
30. The method according to claim 1 , wherein the thermosetting-epoxy-resin component is configured to cure at a temperature between about 20° C. and about 30° C. within a period greater than 5 minutes or to cure at a temperature greater than 150° C. within a period of less than 5 seconds.
31. The method according to claim 1 , wherein the continuous flexible line comprises a prepreg composite material.
32. The method according to claim 1 , further comprising curing the composite part in an autoclave or in an oven.