3D printed core-shell filament and method of 3D printing a core-shell filament

Patent metadata

Field	Value
Publication number	US-11207831-B2
Application number	US-201716466106-A
Country	US
Kind code	B2
Filing date	Dec 5, 2017
Priority date	Dec 8, 2016
Publication date	Dec 28, 2021
Grant date	Dec 28, 2021

Abstract

A 3D printed core-shell filament comprises an elongated core radially surrounded by an outer shell with a barrier layer in between, where the elongated core comprises a ductile polymer and the outer shell comprises a stiff polymer having a Young's modulus higher than that of the ductile polymer. A lightweight lattice structure may comprise a plurality of the 3D printed core-shell filaments deposited in layers.

First claim

The invention claimed is:

1. A 3D printed core-shell filament comprising:
an elongated core radially surrounded by an outer shell with a barrier layer in between,
wherein the elongated core comprises a ductile polymer and the outer shell comprises a stiff polymer having a Young's modulus higher than that of the ductile polymer,
wherein the elongated core has a width or diameter d and the outer shell has a width or diameter D, and wherein a ratio d/D is in a range from about 0.8 to about 0.9.

2. The 3D printed core-shell filament of claim 1 , wherein the barrier layer has a thickness at least about 10 times smaller than a width or diameter D of the outer shell.

3. The 3D printed core-shell filament of claim 1 , wherein the stiff polymer comprises a Young's modulus of at least about 4 GPa.

4. The 3D printed core-shell filament of claim 1 , wherein the ductile polymer comprises a Young's modulus of about 2 GPa or less.

5. The 3D printed core-shell filament of claim 1 , wherein the stiff polymer is selected from the group consisting of: an epoxy, vinylester, polyester and polymethyl methacrylate.

6. The 3D printed core-shell filament of claim 1 , wherein the ductile polymer is selected from the group consisting of: an epoxy, polyurethane, thermoplastic polyurethane and polycarbonate.

7. The 3D printed core-shell filament of claim 1 , wherein one or both of the stiff and ductile polymers comprise an epoxy.

8. The 3D printed core-shell filament of claim 1 , wherein one or both of the stiff and ductile polymers include reinforcement particles dispersed therein.

9. The 3D printed core-shell filament of claim 1 , wherein the barrier layer comprises a barrier polymer having a coefficient of friction of at least about 1 with respect to each of the ductile and stiff polymers.

10. The 3D printed core-shell filament of claim 1 , wherein the barrier layer comprises a barrier polymer selected from the group consisting of: silicone and polytetrafluoroethylene.

11. The 3D printed core-shell filament of claim 1 , wherein the elongated core is hollow.

12. The 3D printed core-shell filament of claim 1 , further comprising a soft external layer on the outer shell, the soft external layer comprising a soft polymer having a lower Young's modulus than the stiff polymer.

Assignees

• Harvard College
• Eth Zurich Swiss Federal Institute Of Tech

Inventors

• Lewis Jennifer A
• Mueller Jochen
• Raney Jordan R
• Shea Kristina

Classifications

• B29C48/02

  Small extruding apparatus, e.g. handheld, toy or laboratory extruders · CPC title

• B33Y70/00

  Materials specially adapted for additive manufacturing · CPC title

• B29C64/209 Primary

  Heads; Nozzles · CPC title

• D06M11/79

  with silicon dioxide, silicic acids or their salts · CPC title

• B29C48/92

  Measuring, controlling or regulating · CPC title