Filament drive mechanism for use in additive manufacturing system and method of printing 3d part

Patent metadata

Field	Value
Publication number	US-2022016837-A1
Application number	US-201917294116-A
Country	US
Kind code	A1
Filing date	Nov 14, 2019
Priority date	Nov 14, 2018
Publication date	Jan 20, 2022
Grant date	—

Abstract

A filament drive mechanism for use with an additive manufacturing system includes at least first and second drives. Each drive includes a first rotatable shaft and a second rotatable shaft engaged with the first rotatable shaft in a counter rotational configuration. Each drive includes a pair of filament engagement elements, one on each rotatable shaft, and positioned on opposing sides of the filament path with a gap therebetween so as to engage a filament provided in the filament path. The drive mechanism includes a bridge follower configured to rotatably couple the first drive to the second drive wherein one of the shafts is a drive shaft configured to be driven by a motor at a rotational rate selected to advance the filament at a desired feed rate and to cause the other shafts to rotate at the same rotational rate, such that each pair of filament engagement teeth will engage a filament in the filament path and will coordinate to advance the filament while counter-rotating at the same rotational rate to drive the filament into a liquefier.

First claim

1 . A filament drive mechanism for use with an additive manufacturing system, the filament drive mechanism comprising:
a filament drive mechanism comprising a first drive and a second drive spaced from each other, each drive comprising:
a first rotatable shaft;
a second rotatable shaft engaged with the first rotatable shaft in a counter rotational configuration;
a pair of filament engagement elements each comprising a plurality of teeth, one on each rotatable shaft, and positioned on opposing sides of the filament path with a gap therebetween so as to engage a filament provided in the filament path; and
a bridge shaft configured to rotatably couple the first drive to the second drive; wherein one of the shafts is a drive shaft configured to be driven by a motor at a rotational rate selected to advance the filament at a desired feed rate and to cause the other shafts to rotate at the same rotational rate, such that each pair of filament engagement teeth will engage a filament in the filament path and will coordinate to advance the filament while counter-rotating at the same rotational rate to drive the filament into a liquefier.

2 . The filament drive system of claim 1 , wherein the drive shaft comprises the first rotatable shaft of the first drive or the second drive.

3 . The filament drive system of claim 1 , wherein the drive shaft comprises the bridge shaft.

4 . The filament drive mechanism of claim 1 , wherein at least four teeth of each of pair of filament engagements elements engage the filament at all times.

5 . The filament drive mechanism of claim 1 wherein the filament engagement elements comprise drive wheels

6 . The filament drive mechanism of claim 1 further including a gear train driven by the motor to rotate the shafts.

7 . The filament drive mechanism of claim 1 , and wherein the at least first and second drives each further comprises:
first gear cogs extending around a circumference of the first rotational shaft; and second gear cogs extending around a circumference of the second rotational shaft, wherein the second gear cogs intermesh with the first gear cogs; and wherein rotation of the first rotational shaft causes rotation of the second rotational shaft in an opposing rotational direction.

8 . The filament drive mechanism of claim 1 , wherein the bridge shaft has gear cogs that engage gear cogs on the first and second drives such that the first and second drives engaging the filament at a substantially similar rate.

9 . The filament drive mechanism of claim 1 , and further comprising a drive block, wherein the drive block comprises:
a channel comprising the filament path; and a plurality of pairs of spaced apart cavities on opposing sides of the filament path, each cavity intersecting the filament path such that portions of the first and second engagement surfaces of the plurality of filament drives are configured to enter the filament path and rotatably engage the filament.

10 . The filament drive mechanism of claim 1 and further comprising a third drive, wherein the second drive is positioned between the first drive and the third drive.

11 . The filament drive mechanism of claim 10 and further comprising:
the first bridge shaft having gear cogs that engage gear cogs on the first and second drives such that power is transferred from the second drive to the first drive;
a second bridge shaft having gear cogs that engage gear cogs on the third and second drives such that power is transferred from the second drive to the third drive; and
wherein the first, second and third drives are configured to engage the filament at a substantially similar rate.

12 . The filament drive mechanism of claim 1 , wherein the teeth have an edge width ranging from about 0.001 inches to about 0.003 inches.

13 . The filament drive mechanism of claim 1 , wherein the teeth have a land width ranging from about 0.08 inches to about 0.15 inches.

14 . The filament drive mechanism of claim 13 , wherein the land width is a substantially flat surface.

15 . The filament drive mechanism of claim 1 , wherein the first filament drive and the same number of teeth, and wherein the teeth of the first drive are in phase with one another, and the teeth of the second drive are in phase with one another.

16 . The filament drive mechanism of claim 1 , wherein the number of teeth in the first drive and the number of teeth in the second drive are different.

17 . The filament drive mechanism of claim 16 , wherein a ratio of teeth in the first drive and the second drive ranges from about 1.5:1 to about 3.0:1.

18 . The filament drive mechanism of claim 15 , wherein the teeth of the first drive are out of phase with the teeth of the second drive

19 . A filament drive mechanism for use in driving an elastomeric filament in an additive manufacturing system, the filament drive mechanism comprising:
a first drive comprising:
a first rotatable shaft;
a second rotatable shaft engaged with the first rotatable shaft in a counter rotational configuration; and
a plurality of teeth on each rotatable shaft, and positioned on opposing sides of a filament path with a gap therebetween so as to engage a filament provided in the filament path wherein the plurality of teeth has a land width ranging from about 0.08 inches to about 0.15 inches.

20 . The filament drive of claim 19 , wherein the plurality of teeth on each shaft are in phase.

21 . The filament drive of claim 19 , and further comprising:
a second drive spaced from the first drive, the second drive comprising:
a third rotatable shaft;
a fourth rotatable shaft engaged with the third rotatable shaft in a counter rotational configuration;
a plurality of teeth on each rotatable shaft of the second drive, and positioned on opposing sides of a filament path with a gap therebetween so as to engage a filament provided in the filament path wherein the plurality of teeth has a land width ranging from about 0.08 inches to about 0.15 inches; and a first bridge shaft configured to rotatably couple the first drive and the second drive.

22 . The filament drive of claim 21 , wherein the second filament drive is spaced from the first filament drive a first selected distance which causes the plurality of teeth in the second drive to engage the filament in substantially a same plurality of locations thereon as the plurality of teeth in the first drive.

23 . The filament drive of claim 21 , and further comprising:
a third drive spaced from the second drive, the third drive comprising:
a fifth rotatable shaft;
a sixth rotatable shaft engaged with the first rotatable shaft in a counter rotational configuration;
a plurality of teeth on each rotatable shaft of the third drive, and positioned on opposing sides of a filament path with a gap therebetween so as to engage a filament provided in the filament path wherein the plurality of teeth has a land width ranging from about 0.08 inches to about 0.15 inches; and a second bridge shaft configured to rotatably couple the second drive and the third drive such that the first, second and third drive rotate at substantially a same rate.

24 . The filament drive mechanism of claim 21 , wherein the teeth of the first drive are in phase with one another, the teeth of the second drive are in phase with one another, and the teeth of the first drive are out of phase with the teeth of the second drive.

25 . A filamen

Assignees

• Stratasys Inc

Inventors

• Pekarna Matt
• Koop Shawn
• Schuller Peter
• Nadeau Jordan
• Alvig David

Classifications

• B29C64/321

  Feeding · CPC title

• B29C64/227 Primary

  Driving means · CPC title

• B33Y10/00

  Processes of additive manufacturing · CPC title

• B29C64/118

  using filamentary material being melted, e.g. fused deposition modelling [FDM] · CPC title

• B33Y30/00

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