High-precision modeling filament

• US 6,866,807 B2
• Filed: 04/17/2002
• Issued: 03/15/2005
• Est. Priority Date: 09/21/2001
• Status: Active Grant

• Current Assignee: Startasys, Inc.
• Original Assignee: Stratasys Incorporated
• Inventors: Priedeman, William R. Jr., Comb, James W., Skubic, Robert L., Batchelder, John Samuel, Leavitt, Paul J.
• Primary Examiner(s): Eashoo, Mark
• Application Number:
  US10/124,241
• Publication Number:
  US 20030056870A1
• Time in Patent Office: 1,063 Days
• Field of Search: 156/64, 264/255, 264/308, 264/177.1, 425/145, 425/147, 425/166, 425/162
• US Class Current: 264/255
• CPC Class Codes: B29C 2948/92123 Diameter or circumference
• CPC Class Codes: B29C 2948/92409 Die; Nozzle zone
• CPC Class Codes: B29C 2948/92523 Force; Tension
• CPC Class Codes: B29C 2948/92571 Position, e.g. linear or angular
• CPC Class Codes: B29C 2948/9259 Angular velocity
• CPC Class Codes: B29C 2948/92619 Diameter or circumference
• CPC Class Codes: B29C 2948/92904 Die; Nozzle zone
• CPC Class Codes: B29C 2948/92933 Conveying, transporting or storage of articles
• CPC Class Codes: B29C 2948/92952 Drive section, e.g. gearbox, motor or drive fluids
• CPC Class Codes: B29C 48/05 Filamentary, e.g. strands
• CPC Class Codes: B29C 48/625 characterised by the ratio of the threaded length of the screw to its outside diameter [L/D ratio]
• CPC Class Codes: B29C 48/92 Measuring, controlling or regulating
• CPC Class Codes: B29C 64/106 using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material
• CPC Class Codes: B29C 64/118 using filamentary material being melted, e.g. fused deposition modelling [FDM]
• CPC Class Codes: B33Y 70/00 Materials specially adapted for additive manufacturing
• CPC Class Codes: B33Y 80/00 Products made by additive manufacturing
• CPC Class Codes: Y10T 428/2913 Rod, strand, filament or fiber
• CPC Class Codes: Y10T 428/298 Physical dimension

Abstract

Disclosed is a modeling filament for use as feedstock in a fused deposition modeling liquifier, and a method for manufacturing the filament. The diameter and standard deviation of the filament are controlled to meet various tolerance requirements of jam resistance, slip resistance, model strength, liquifier overflow prevention and hysteresis-free transient response. Standard deviation of the filament diameter is matched to a filament target diameter. The resulting filament is used to form high-quality models.

Claims

1. A method of forming a three-dimensional object in a fused deposition modeling machine which includes a liquifier having an inner diameter d_L and which receives a feedstock of solid modeling material and deposits melted material in roads of width W and height L, the method comprising the steps of:

using as the modeling material feedstock a filament having an average diameter <

d_F>

according to the relationship 0.84 d_L<

<

d_F>

<

d_L−

6σ

_F and a standard deviation σ

_F of;

${\mathrm{\sigma <br><br>}}_F\le <br><br>\frac{2<br><br>{\mathrm{LWS}}_s}{3<br><br>\mathrm{\pi <br><br>}<<br><br>\text{\hspace{1em}<br><br>}<br><br>d_F><br><br>\mathrm{\Delta <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>S_g}$

where S_S is a maximum allowable seam gap at a junction of two roads, and Δ

S_g is expected average movement of a meniscus within the liquifier.

2. The method of claim 1, wherein <

d_F>

is between 0.069-0.074 inches and σ

_F is less than or equal to 0.0004 inches.

3. The method of claim 2, wherein d_L is approximately 0.076 inches.

4. The method of claim 1, wherein <

d_F>

is between 0.071-0.072 inches and σ

_F is less than or equal to 0.0003 inches.

5. The method of claim 1, wherein <

d_F>

is between 0.072-0.073 inches and σ

_F is less than or equal to 0.00015 inches.

6. The method of claim 1, wherein the filament is a thermoplastic and the standard deviation σ

_F also obeys;

σ

_F≦

0.007·

<

d_F>

.

7. The method of claim 1, wherein the standard deviation σ

_F also obeys;

${\mathrm{\sigma <br><br>}}_F\le <br><br>\frac{<<br><br>d_F><br><br>}{3}<br><br>\left(\sqrt{\frac{100}{F_T}}-1\right)$

where F_T is a target fill percentage of the object.

8. A method of forming a three dimensional object in a fused deposition modeling machine which includes a liquifier having an inner diameter d_L and which receives a feedstock of solid modeling material and deposits melted material in roads of width W and height L, the method comprising the steps of:

using as the modeling feedstock a filament having a length greater than 20 feet, having an average diameter of between 0.069-0.074 inches, and having a standard deviation of the diameter of less than or equal to 0.0004 inches.

9. The method of claim 8, wherein d_L is approximately 0.076 inches.

10. The method of claim 8, wherein <

d_F>

is between 0.071-0.072 inches and σ

_F is less than or equal to 0.0003 inches.

11. The method of claim 8, wherein <

d_F>

is between 0.072-0.073 inches and σ

_F is less than or equal to 0.00015 inches.

12. A method of extrusion in an extrusion apparatus of the type that includes a liquifier having an inner diameter d_L which receives a feedstock of a solid material and a tip which deposits said material in molten form in roads of width W and height L, the method comprising the step of:

using as the feedstock a filament having an average diameter <

d_F>

according to the relationship 0.84 d_L<

<

d_F>

<

d_L−

6σ

_F. and a standard deviation σ

_F of;

${\mathrm{\sigma <br><br>}}_F\le <br><br>\frac{2<br><br>{\mathrm{LWS}}_s}{3<br><br>\mathrm{\pi <br><br>}<<br><br>\text{\hspace{1em}<br><br>}<br><br>d_F><br><br>\mathrm{\Delta <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>S_g}$

where S_S is a maximum allowable seam gap at a junction of two roads, and Δ

S_g is expected average movement of a meniscus within the liquifier.

13. The method of claim 12, wherein <

d_F>

is between 0.069-0.074 inches and σ

_F is less than or equal to 0.0004 inches.

14. The method of claim 13, wherein d_L is approximately 0.076 inches.

15. The method of claim 12, wherein <

d_F>

is between 0.071-0.072 inches and σ

_F is less than or equal to 0.0003 inches.

16. The method of claim 12, wherein <

d_F>

is between 0.072-0.073 inches and σ

_F is less than or equal to 0.00015 inches.

17. The method of claim 12, wherein the filament is a thermoplastic and the standard deviation σ

_F also obeys;

σ

_F≦

0.007·

<

d_F>

18. The method of claim 12, and further comprising the step of:

depositing roads of molten material in a predetermined three-dimensional pattern to thereby build a three-dimensional object having a target fill percentage F_T, wherein the standard deviation σ

_F of the filament also obeys;

${\mathrm{\sigma <br><br>}}_F\le <br><br>\frac{<<br><br>d_F><br><br>}{3}<br><br>\left(\sqrt{\frac{100}{F_T}}-1\right).$

19. A method of extrusion in an extrusion apparatus of the type that includes a liquifier which receives a feedstock of a solid material and a tip which deposits said material in molten form in roads of width W and height L, the method comprising the step of:

using as the feedstock a filament having a length greater than 20 feet, having an average diameter <

d_F>

of between 0.069-0.074 inches, and having a standard deviation of the diameter σ

_F of less than or equal to 0.0004 inches.

20. The method of claim 19, and further comprising the step of:

feeding the filament into a channel of the liquifier having an inner diameter d_L approximately equal to 0.076 inches.

21. The method of claim 19, wherein <

d_F>

is between 0071-0.072 inches and σ

_F is less than or equal to 0.0003 inches.

22. The method of claim 19, wherein <

d_F>

is between 0.072-0.073 inches and σ

_F is less than or equal to 0.00015 inches.

23. The method of claim 19, and further comprising the step of:

depositing roads of molten material in a predetermined three-dimensional pattern to thereby build a three-dimensional object.