Additive manufacturing with heat-flexed material feeding

Patent metadata

Field	Value
Publication number	US-2018154437-A1
Application number	US-201715831995-A
Country	US
Kind code	A1
Filing date	Dec 5, 2017
Priority date	Dec 6, 2016
Publication date	Jun 7, 2018
Grant date	—

Abstract

In additive manufacturing, composite build material filament and release material filament (each a composite of metal/ceramic powder plus binder) are dropped from respective spools to a print head. On the spools and over the drop height, the filaments are heated to a temperature that flexes the filaments but does not soften them to a breaking point, e.g., heated but below a glass transition temperature of a softener (for example, wax) of the binder. The drop height is of similar linear scale to the build plate. The materials are debound and sintered.

First claim

What is claimed is:

1 . A method of additive manufacturing, comprising:
dropping a build material filament, including a first binder and more than 50% by volume of sinterable powdered metal, over a drop height from a first spool to a print head assembly; dropping a release material filament, including a second binder and a powdered ceramic, over the drop height from a second spool to the print head assembly; heating the build material filament on the first spool and along the drop height to a temperature lower than a glass transition temperature of a softening component of the first binder to flex the build material filament; depositing layers of the build material filament and the release material filament above a build plate, the drop height being substantially equal to or longer than a diagonal of the build plate; debinding the first binder and the second binder with a common solvent to form a brown part assembly including each of the build material filament and the release material filament; and sintering the brown part assembly while decomposing the release material to a release powder.

2 . The method according to claim 1 , wherein the build material filament dropped along the drop height has a bend radius of more than 10 cm.

3 . The method according to claim 2 , further comprising heating the build plate by a build plate heater to 50-120 degrees C.

4 . The method according to claim 2 , further comprising:
positioning the build plate below the drop height; and heating the build material filament along the drop height assisted by convection heat rising from the heated build plate.

5 . The method according to claim 1 , wherein the first binder includes a polymer in addition to the softening component, and the softening component includes a solvent-extractable non-polymer component selected from a wax, a fatty acid, a fatty acid ester, a fatty alcohol, an alkane, a petrolatum, a naphthalene, a glycol, and a glycerol.

6 . The method according to claim 1 , further comprising:
laterally transporting the print head assembly to traverse a print area of more than 50% of the surface area of the build plate, so that the build material filament is unwound from the first spool by the lateral transporting of the print head assembly.

7 . The method according to claim 6 , further comprising:
guiding the build material filament with a flexible Bowden tube leading to the print head assembly, the flexible Bowden tube being less than ⅓ of the drop height.

8 . The method according to claim 1 , wherein the build material filament cross sectional diameter is more than 0.5 mm but less than 2 mm.

9 . The method according to claim 8 , wherein a cross sectional diameter of the build material filament is equal to or less than substantially 1 mm, and the temperature is greater than 40 degrees C.

10 . The method according to claim 8 , wherein a cross sectional diameter of the build material filament is equal to or less than substantially 2 mm, and the temperature is greater than 50 degrees C. and less than substantially 55 degrees C.

11 . A method of additive manufacturing, comprising:
winding a build material filament on a first spool, the build material filament including a first binder and more than 50% by volume of sinterable powdered metal, the winding being controlled to be at a first temperature lower than a glass transition temperature of a softenable component of the first binder and to wind at a bend radius of more than 2 cm; transporting the first spool at uncontrolled ambient temperatures; unwinding a build material filament from the first spool with a first feed mechanism; maintaining the first spool and the drawn build material filament in a heated chamber at a second temperature higher than room temperature but lower than the glass transition temperature of a softenable component of the first binder; depositing layers of a release material; depositing layers of the build material filament upon the prior deposition of the release material; debinding at least a portion of the first binder to form a brown part assembly including the build material filament; and sintering the brown part assembly.

12 . The method according to claim 11 , wherein a free span of the build material filament hangs between the first spool and the first feed mechanism, the free span having a bend radius of more than 10 cm.

13 . The method according to claim 12 , further comprising depositing layers of the build material filament above a build plate heated by a build plate heater to 50-120 degrees C., wherein the free span is substantially equal to or longer than a diagonal of the build plate.

14 . The method according to claim 13 , further comprising:
positioning the build plate below the free span; and heating the free span to the second temperature assisted by convection heat rising from the heated build plate.

15 . The method according to claim 14 , further comprising:
positioning the first spool vertically above the free span and the build plate; and heating the first spool to the second temperature assisted by convection heat rising from the heated build plate.

16 . The method according to claim 13 , further comprising:
laterally transporting the first feed mechanism together with a print head traversing a print area of more than 50% of the surface area of the build plate, so that the build material filament is unwound from the first spool by the first feed mechanism and by the lateral transporting of the first feed mechanism.

17 . The method according to claim 16 , further comprising:
guiding the build material filament with a flexible Bowden tube leading to the first feed mechanism, the flexible Bowden tube being less than ⅓ of the free span.

18 . The method according to claim 11 , wherein a cross sectional diameter of the build material filament is more than 0.5 mm but less than 2 mm.

19 . The method according to claim 18 , wherein the cross sectional diameter of the build material filament is equal to or less than substantially 1 mm, and the second temperature is greater than 40 degrees C.

20 . The method according to claim 18 , wherein the cross sectional diameter of the build material filament is equal to or less than substantially 2 mm, and the second temperature is greater than 50 degrees C. and less than substantially 55 degrees C.

Assignees

• Markforged Inc

Inventors

• Mark Gregory Thomas

Classifications

• B22F10/64

  by thermal means (control of energy beam parameters for post heating B22F10/364) · CPC title

• B22F10/40

  Structures for supporting workpieces or articles during manufacture and removed afterwards · CPC title

• B22F1/142

  Thermal or thermo-mechanical treatment · CPC title

• B22F10/16

  by embedding the binder within the powder bed · CPC title

• B22F3/1025 Primary

  not by heating only · CPC title