Method For Analytically Determining SLS Bed Temperatures

• US 20150061195A1
• Filed: 08/29/2014
• Published: 03/05/2015
• Est. Priority Date: 08/29/2013
• Status: Active Grant

• Current Assignee: Hexcel Corporation
• Original Assignee: Hexcel Corporation
• Inventors: DeCarmine, Anthony, DeFelice, Scott
• Granted Patent: US 9,937,667 B2
• Time in Patent Office: Days
• US Class Current: 264/497
• CPC Class Codes: B29B 9/16 Auxiliary treatment of granules
• CPC Class Codes: B29C 64/153 using layers of powder being selectively joined, e.g. by selective laser sintering or melting
• CPC Class Codes: B29C 64/386 Data acquisition or data processing for additive manufacturing
• CPC Class Codes: B29C 64/393 for controlling or regulating additive manufacturing processes
• CPC Class Codes: B29K 2071/00 Use of polyethers , e.g. PEEK, i.e. polyether-etherketone or PEK, i.e. polyetherketone or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2105/251 Particles, powder or granules expandable particles B29K2105/046
• CPC Class Codes: B33Y 50/02 for controlling or regulating additive manufacturing processes
• CPC Class Codes: C08G 2650/40 containing ketone groups, e.g. polyarylethylketones, PEEK or PEK
• CPC Class Codes: C08L 71/00 Compositions of polyethers obtained by reactions forming an ether link in the main chain of polyacetals C08L59/00; of epoxy resins C08L63/00; of polythioether-ethers C08L81/02; of polyether-sulfones C08L81/06; Compositions of derivatives of such polymers

Abstract

A method for determining a bed temperature setpoint for use with a powder in a selective laser sintering machine is disclosed. The method includes the step of providing a powder comprising a polymer for use in a selective laser sintering machine. The method further includes the step of determining a ratio of a liquid portion of the powder to a solid portion of the powder as a function of temperature within a temperature range. A bed temperature setpoint is selected in the temperature range corresponding to a desired ratio of the liquid portion of the powder to the solid portion of the powder. A temperature of a bed of a selective laser sintering machine is set to the selected bed temperature setpoint, and a part is built from the powder using the selective laser sintering machine.

Claims

1. A method for determining a bed temperature setpoint for use with a powder in a selective laser sintering machine, comprising the steps of:

providing a powder comprising a polymer for use in a selective laser sintering machine;

determining a ratio of a liquid portion of the powder to a solid portion of the powder as a function of temperature within a temperature range;

selecting a bed temperature setpoint in the temperature range corresponding to a desired ratio of the liquid portion of the powder to the solid portion of the powder.

2. The method of claim 1, further comprising the steps of:

providing a selective laser sintering machine having a bed with a variable temperature control;

setting a temperature of the bed to the selected bed temperature setpoint;

building a part from the powder using the selective laser sintering machine.

3. The method of claim 2, further comprising the step of:

determining a melt curve for the powder in the temperature range, the melt curve representing the energy required to increase the temperature of the powder in the temperature range.

4. The method of claim 3, further comprising the step of:

using differential scanning calorimetry to determine the melt curve for the powder.

5. The method of claim 4, further comprising the step of:

determining the ratio of the liquid portion of the powder to the solid portion of the powder as a function of temperature based on the melt curve.

6. The method of claim 5, further comprising the step of:

selecting the desired ratio by referencing a library comprising data associated with a plurality of parts made using a standard powder with a selective laser sintering machine, each said part being made using a different bed temperature setpoint, each bed temperature setpoint corresponding to a different ratio of a liquid portion of the powder to a solid portion of the powder.

7. The method of claim 5, wherein the standard powder comprises a polymer, and the standard powder is different than the powder for which the desired ratio is being selected.

8. The method of claim 7, wherein the library comprises accuracy data corresponding to an accuracy of the part relative to a design used to make the part.

9. The method of claim 7, wherein the library comprises removal data corresponding to the ease or difficulty of removing the part from a powder cake surrounding the part.

10. A method for determining a bed temperature setpoint for use with a powder in a selective laser sintering machine, comprising the steps of:

providing a powder comprising one or more of polyetheretherketone (“

PEEK”

), polyetherketone ketone (“

PEKK”

), polyetherketone (“

PEK”

), polyetheretherketoneketone (“

PEEKK”

), or polyetherketoneetherketoneketone (“

PEKEKK”

);

determining a ratio of a liquid portion of the powder to a solid portion of the powder as a function of temperature within a temperature range;

selecting a bed temperature setpoint in the temperature range corresponding to a desired ratio of the liquid portion of the powder to the solid portion of the powder.

11. The method of claim 10, further comprising the steps of:

providing a selective laser sintering machine having a bed with a variable temperature control;

setting a temperature of the bed to the selected bed temperature setpoint;

building a part from the powder using the selective laser sintering machine.

12. The method of claim 11, wherein the powder comprises recycled PEKK.

13. The method of claim 12, wherein the powder comprises virgin PEKK.

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

determining a melt curve for the powder in the temperature range, the melt curve representing the energy required to increase the temperature of the powder in the temperature range.

15. The method of claim 14, further comprising the step of:

determining the ratio of the liquid portion of the powder to the solid portion of the powder as a function of temperature based on the melt curve.

16. The method of claim 15, further comprising the step of:

selecting the desired ratio by referencing a library comprising data associated with a plurality of parts made using a powder comprising virgin PEKK and excluding recycled PEKK with a selective laser sintering machine, each said part being made using a different bed temperature setpoint, each bed temperature setpoint corresponding to a different ratio of a liquid portion of the powder to a solid portion of the powder.