System and method for extruding composite filament

Patent metadata

Field	Value
Publication number	US-11498255-B2
Application number	US-201816772223-A
Country	US
Kind code	B2
Filing date	Dec 17, 2018
Priority date	Dec 15, 2017
Publication date	Nov 15, 2022
Grant date	Nov 15, 2022

Abstract

A method of extruding filament comprises the steps of cutting a bulk source material into pieces having size S1, performing a first extrusion pass comprising the steps of melting the pieces in an extruding device at a temperature T1 and extruding a first filament at an extrusion speed V1, and performing at least one additional extrusion pass k comprising the steps of cutting the first filament into pieces having size Sk, melting the pieces in an extruding device at temperature Tk, and extruding a final filament at an extrusion speed Vk. A system for extruding filament is also described.

First claim

What is claimed is:

1. A method of extruding filament, comprising the steps of:
producing pieces of source material having size S 1 ;
performing a first extrusion pass comprising the steps of:
melting the first pieces in an extruding device at a temperature T 1 ; and
extruding a first filament from an extruding device having an extrusion screw, at an extrusion speed V 1 ; and

performing at least one additional extrusion pass k comprising the steps of:
cutting the first filament into second pieces having size S k ;
melting the second pieces in an extruding device at temperature T k ; and
extruding a final filament at an extrusion speed V k ;

wherein the matrix porosity of the final filament is less than the matrix porosity of the first filament.

2. The method of claim 1 , wherein the source material comprises polymer matrix syntactic foam.

3. The method of claim 2 , wherein the source material is HDPE.

4. The method of claim 1 , further comprising the steps of:
monitoring at least one temperature on the extruding device; and
activating at least one heater in order to maintain at least one temperature substantially constant.

5. The method of claim 1 , wherein the first pieces of source material are produced by cutting a bulk source material.

6. The method of claim 1 , wherein the first pieces of source material are produced by melting and casting a bulk source material.

7. The method of claim 1 , wherein T 1 and T k are above the glass transition temperature of the source material and below the melting temperature of the source material.

8. The method of claim 1 , wherein S 1 is less than the pitch of the extruder screw.

9. The method of claim 1 , wherein V 1 and V k are between 1 mm/sec and 2 cm/sec.

10. The method of claim 7 , wherein T 1 and T k are different values.

11. The method of claim 8 , wherein S 1 and S k are different values.

12. The method of claim 9 , wherein V 1 and V k are different values.

Assignees

• Univ New York

Inventors

• Gupta Nikhil
• Saltonstall Brooks
• Singh Ashish Kumar

Classifications

• B33Y10/00

  Processes of additive manufacturing · CPC title

• B29C2948/92209

  Temperature · CPC title

• B33Y40/00

  Auxiliary operations or equipment, e.g. for material handling · CPC title

• B33Y70/00

  Materials specially adapted for additive manufacturing · CPC title

• B29C48/0013 Primary

  Extrusion moulding in several steps, i.e. components merging outside the die (B29C48/15 takes precedence) · CPC title