Wear resistance in 3D printing of composites

Patent metadata

Field	Value
Publication number	US-10259160-B2
Application number	US-201715436216-A
Country	US
Kind code	B2
Filing date	Feb 17, 2017
Priority date	Mar 22, 2013
Publication date	Apr 16, 2019
Grant date	Apr 16, 2019

Abstract

A three dimensional printer which prints at using at least one composite material having an inherently abrasive filler or fiber material has a Mohs hardness greater than substantially 1, or a Knoop/Vickers hardness greater than substantially 300 kg/mm 2 , or a Rockwell C hardness at least C30, and where a nozzle tip may contact a top surface of a previously deposited line of material may have a nozzle body includes a material having a thermal conductivity at least 35 w/M-K to conduct heat to the nozzle, and a nozzle throat and/or nozzle tip each include a material having a Rockwell C hardness at least C40, to resist wear from sliding contact of the nozzle tip with the previously deposited lines of the material being printed or another previously deposited material, or from the material being printed as it is printed through the nozzle throat.

First claim

What is claimed is:

1. A three dimensional printer for printing a part with a composite material including a thermoplastic matrix and a chopped fiber filler having a hardness more than two times the hardness of the thermoplastic matrix, comprising:
a drive wheel for advancing the composite material;
a heated nozzle through which the composite material is deposited, the heated nozzle including:
a nozzle body through which heat is applied to the composite material, the nozzle body being formed from a material having a thermal conductivity of at least substantially 35 w/M-K;
an interior nozzle throat within the nozzle body through which the composite material exits, the interior nozzle throat formed from a material having a Rockwell C hardness of at least substantially C50 and configured to resist abrasion from the chopped fiber filler of the composite material exiting the interior nozzle throat; and
an exterior nozzle tip having an exterior surface formed from a material having a Rockwell C hardness of at least substantially C40 and configured to rub against a top surface of a previously deposited part and to resist abrasion from the chopped fiber filler in the composite material of the previously deposited part; and

a cutter arranged along a composite material supply path from a supply of the composite material to the exterior nozzle tip, the cutter positioned following the drive wheel for advancing the material and including a blade having a Rockwell C hardness of at least substantially C60.

2. The three dimensional printer according to claim 1 , wherein the nozzle body is formed from a material having a thermal conductivity of substantially 50 w/M-K or higher.

3. The three dimensional printer according to claim 1 , wherein the nozzle throat is formed from a material having a Rockwell C hardness at least substantially C60.

4. The three dimensional printer according to claim 3 , wherein the nozzle throat and nozzle tip each are formed from a material having a Rockwell C hardness at least substantially C60.

5. The three dimensional printer according to claim 1 , wherein a portion of the nozzle body, the nozzle throat, and the nozzle tip is unitarily formed from a material having a thermal conductivity of at least substantially 60 w/M-K as well as Rockwell C hardness of at least substantially C60.

6. The three dimensional printer according to claim 1 , wherein a portion of the nozzle body, the nozzle throat, and nozzle tip is unitarily formed from one of a sintered carbide and a sintered nitride.

7. The three dimensional printer according to claim 1 , wherein a majority of the thermal mass of the nozzle body includes a material having a thermal conductivity of substantially 200 w/M-K or higher, and the nozzle throat and nozzle tip are formed within a nozzle tip insert having a thermal conductivity of at least substantially 100 w/M-K as well as at least a Rockwell C hardness of substantially C60.

8. The three dimensional printer according to claim 7 , wherein the insert is a tapered insert having a nozzle tip with a surface area lower than a nozzle cross sectional area adjacent the tip, such that the nozzle tip increases in area and wears at a lower rate as material is worn away.

9. The three dimensional printer according to claim 8 , wherein the nozzle body includes a cavity behind the nozzle throat of larger internal diameter than the nozzle throat diameter.

10. The three dimensional printer according to claim 9 , wherein the nozzle body includes a chamfer leading from the larger cavity diameter to the smaller nozzle throat diameter.

11. The three dimensional printer according to claim 10 , wherein a nozzle throat and nozzle tip are unitary in a nozzle insert held within the nozzle body by one of a crimp and a braze.

12. The three dimensional printer according to claim 1 , further comprising at least one curved guide tube arranged along the material supply path, the curved guide tube having at least one curved or curvable section formed in one or more pieces from a material having a Rockwell C hardness at least substantially C25.

13. The three dimensional printer according to claim 1 , further comprising at least one drive wheel for advancing the composite material, the at least one drive wheel having a drive surface including a material having a Rockwell C hardness of at least substantially C25.

14. The three dimensional printer according to claim 13 , wherein the at least one drive wheel being at least one of roughened, textured, hobbed, and stepped.

15. The three dimensional printer according to claim 13 , wherein the at least one drive wheel comprises one drive wheel opposing one idle wheel, in which one of the drive wheel and the idle wheel is at least one of roughened, textured, hobbed, and stepped and the remaining one of the drive wheel and the idle wheel is substantially smooth.

16. The three dimensional printer according to claim 13 , wherein the at least one drive wheel comprises one drive wheel opposing one idle wheel, in which both opposing wheels are formed from a material having a Rockwell C hardness at least substantially C25.

17. The three dimensional printer according to claim 13 , wherein the at least one drive wheel comprises one drive wheel opposing one idle wheel, and at least one of the drive wheel and idle wheel includes a relative or absolute encoder for measuring at least one of rotation speed and motor stall.

18. The three dimensional printer of claim 1 , wherein a portion of the nozzle body, the nozzle throat, and the nozzle tip is unitarily formed.

19. The three dimensional printer of claim 1 , wherein the heated nozzle is configured to increase velocity of the composite material as the composite material passes through the nozzle throat.

Assignees

• Markforged Inc

Inventors

• Mark Gregory Thomas

Classifications

• B29C64/209

  Heads; Nozzles · CPC title

• B29C64/20

  Apparatus for additive manufacturing; Details thereof or accessories therefor · CPC title

• B33Y30/00

  Apparatus for additive manufacturing; Details thereof or accessories therefor · CPC title

• B29C31/042

  using dispensing heads, e.g. extruders, placed over or apart from the moulds (positioning extruded preforms on conveyors B29C31/085) · CPC title

• B29K2307/04

  Carbon · CPC title