Laser-produced porous surface

• US 8,992,703 B2
• Filed: 09/06/2012
• Issued: 03/31/2015
• Est. Priority Date: 11/08/2002
• Status: Active Grant

• Current Assignee: University of Liverpool
• Original Assignee: Howmedica Osteonics Corp. (Stryker Corporation), University of Liverpool
• Inventors: O'Neill, William, Sutcliffe, Christopher J., Jones, Eric, Stamp, Robin
• Primary Examiner(s): Kastler, Scott
• Assistant Examiner(s): LUK, VANESSA TIBAY
• Application Number:
  US13/605,354
• Publication Number:
  US 20130056912A1
• Time in Patent Office: 936 Days
• Field of Search: 752/28, 75245-250, 75/101.3, 148512-514, 148/516, 148/524, 148/525, 148527-536
• US Class Current: 148/525
• CPC Class Codes: A61F 2/30767 Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• CPC Class Codes: A61F 2/30771 applied in original prostheses, e.g. holes or grooves
• CPC Class Codes: A61F 2/30907 Nets or sleeves applied to surface of prostheses or in cement
• CPC Class Codes: A61F 2/3094 Designing or manufacturing processes
• CPC Class Codes: A61F 2/30965 Reinforcing the prosthesis by embedding particles or fibres during moulding or dipping
• CPC Class Codes: A61F 2/34 Acetabular cups
• CPC Class Codes: A61F 2/3662 Femoral shafts
• CPC Class Codes: A61F 2/3859 Femoral components
• CPC Class Codes: A61F 2/389 Tibial components A61F2/3868 takes precedence
• CPC Class Codes: A61F 2002/30006 differing in density or specific weight
• CPC Class Codes: A61F 2002/30011 differing in porosity
• CPC Class Codes: A61F 2002/30153 rectangular
• CPC Class Codes: A61F 2002/30199 Three-dimensional shapes
• CPC Class Codes: A61F 2002/30261 parallelepipedal
• CPC Class Codes: A61F 2002/30915 made of a stack of bonded perforated sheets, grids or wire meshes
• CPC Class Codes: A61F 2002/3092 having an open-celled or open-pored structure
• CPC Class Codes: A61F 2002/30929 having at least two superposed coatings
• CPC Class Codes: A61F 2002/3093 for promoting ingrowth of bone tissue
• CPC Class Codes: A61F 2002/30968 Sintering
• CPC Class Codes: A61F 2002/3097 using laser
• CPC Class Codes: A61F 2002/30971 : Laminates, i.e. layered products
• CPC Class Codes: A61F 2230/0019 : rectangular
• CPC Class Codes: A61F 2230/0063 : Three-dimensional shapes
• CPC Class Codes: A61F 2230/0082 : parallelepipedal
• CPC Class Codes: A61F 2250/0015 : differing in density or specific weight
• CPC Class Codes: A61F 2250/0023 : differing in porosity
• CPC Class Codes: A61F 2310/00017 : Iron- or Fe-based alloys, e.g. stainless steel
• CPC Class Codes: A61F 2310/00023 : Titanium or titanium-based alloys, e.g. Ti-Ni alloys
• CPC Class Codes: A61F 2310/00029 : Cobalt-based alloys, e.g. Co-Cr alloys or Vitallium
• CPC Class Codes: A61F 2310/00095 : Niobium or Nb-based alloys
• CPC Class Codes: A61F 2310/00131 : Tantalum or Ta-based alloys
• CPC Class Codes: A61F 2310/00401 : Coating made of iron, of stainless steel or of other Fe-based alloys
• CPC Class Codes: A61F 2310/00407 : Coating made of titanium or of Ti-based alloys
• CPC Class Codes: A61F 2310/00413 : Coating made of cobalt or of Co-based alloys
• CPC Class Codes: A61F 2310/00491 : Coating made of niobium or Nb-based alloys
• CPC Class Codes: A61F 2310/00544 : Coating made of tantalum or Ta-based alloys
• CPC Class Codes: B22F 10/28 : Powder bed fusion, e.g. selective laser melting [SLM] or electron beam melting [EBM]
• CPC Class Codes: B22F 10/36 : of energy beam parameters
• CPC Class Codes: B22F 10/366 : Scanning parameters, e.g. hatch distance or scanning strategy
• CPC Class Codes: B22F 10/37 : of powder bed aspects, e.g. density
• CPC Class Codes: B22F 10/38 : to achieve specific product aspects, e.g. surface smoothness, density, porosity or hollow structures
• CPC Class Codes: B22F 10/80 : Data acquisition or data processing
• CPC Class Codes: B22F 2301/15 : Nickel or cobalt
• CPC Class Codes: B22F 2301/20 : Refractory metals
• CPC Class Codes: B22F 2301/205 : Titanium, zirconium or hafnium
• CPC Class Codes: B22F 2301/35 : Iron
• CPC Class Codes: B22F 2999/00 : Aspects linked to processes or compositions used in powder metallurgy
• CPC Class Codes: B22F 3/1103 : with particular physical characteristics
• CPC Class Codes: B22F 3/1115 : comprising complex forms, e.g. honeycombs
• CPC Class Codes: B22F 7/004 : comprising at least one non-porous part
• CPC Class Codes: B23K 2101/35 : Surface treated articles
• CPC Class Codes: B23K 2103/05 : Stainless steel
• CPC Class Codes: B23K 2103/08 : Non-ferrous metals or alloys
• CPC Class Codes: B23K 2103/14 : Titanium or alloys thereof
• CPC Class Codes: B23K 2103/26 : Alloys of Nickel and Cobalt and Chromium
• CPC Class Codes: B23K 2103/50 : Inorganic material, e.g. metals, not provided for in B23K2103/02 – B23K2103/26
• CPC Class Codes: B23K 26/382 : by boring
• CPC Class Codes: B23K 26/40 : taking account of the properties of the material involved
• CPC Class Codes: B29C 64/153 : using layers of powder being selectively joined, e.g. by selective laser sintering or melting
• CPC Class Codes: B33Y 10/00 : Processes of additive manufacturing
• 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: C23C 24/04 : Impact or kinetic deposition of particles
• CPC Class Codes: C23C 24/10 : with intermediate formation of a liquid phase in the layer
• CPC Class Codes: C23C 26/02 : applying molten material to the substrate
• CPC Class Codes: C23C 4/02 : Pretreatment of the material to be coated, e.g. for coating on selected surface areas
• CPC Class Codes: C23C 4/12 : characterised by the method of spraying
• CPC Class Codes: C23C 4/18 : After-treatment
• CPC Class Codes: Y02P 10/25 : Process efficiency

Abstract

The present invention disclosed a method of producing a three-dimensional porous tissue in-growth structure. The method includes the steps of depositing a first layer of metal powder and scanning the first layer of metal powder with a laser beam to form a portion of a plurality of predetermined unit cells. Depositing at least one additional layer of metal powder onto a previous layer and repeating the step of scanning a laser beam for at least one of the additional layers in order to continuing forming the predetermined unit cells. The method further includes continuing the depositing and scanning steps to form a medical implant.

Claims

1. A method of producing a three-dimensional porous structure comprising:

depositing a first layer of a metal powder onto a substrate;

scanning a beam at least once over the first layer of metal powder to remelt the metal powder in order to create at least two solid portions separated from one another so as to give a required pore size;

depositing a second layer of metal powder onto the first layer; and

repeating the scanning steps for each successive layer until a desired height is reached.

2. The method according to claim 1, wherein during said step of repeating said scanning steps, at least one scan is carried out angled relative to another scan in order to develop an interconnecting or non-interconnecting porosity.

3. The method according to claim 1, wherein said substrate is a base or core made of a metal selected from the group consisting of titanium, titanium alloys, stainless steel, cobalt chrome alloys, tantalum and niobium, wherein said first layer is fused to said base or core.

4. The method according to claim 3, wherein said core is integral with said resultant porous structure and imparts additional physical properties to the overall construct.

5. The method according to claim 3, wherein said core is detached from a resultant porous surface buildup.

6. The method according to claim 3, wherein a third element is added between said base and said first layer of metal powder to form a bond coat on said substrate.

7. The method according to claim 1, wherein the beam is a laser beam.

8. The method according to claim 1, wherein the beam is an electron beam.

9. A method of producing a three-dimensional porous structure having a varying porosity comprising the steps of:

depositing a first layer of a metal powder onto a substrate;

scanning a beam having a power (P) for a period of time (μ

sec) with a point distance (μ

m), so as to melt said metal powder at predetermined locations to form portions of a plurality of predetermined unit cells within said metal powder layer;

depositing at least one additional layer of metal powder onto said first layer;

repeating the step of scanning a beam for at least one of said deposited metal powder layers in order to continue forming said portions of said predetermined unit cells; and

varying porosity within said three-dimensional porous structure by at least one of (i) forming a unit cell in one metal powder layer having at least one of (a) a different shape from a unit cell within a successive metal powder layer and (b) at least one strut having a different dimension from a corresponding strut of a unit cell of the same shape within a successive metal powder layer, and (ii) applying a random perturbation in any direction to vertices of the unit cells to randomize the geometry of the unit cells.

10. The method according to claim 9, wherein at least one layer of said metal powder has a thickness between 5 μ

m and 2000 μ

m.

11. The method according to claim 9, further comprising predetermining a porosity range for at least one deposited metal powder layer and scanning said at least one deposited metal powder layer in a manner to provide said deposited metal powder layer with a porosity within said porosity range.

12. The method according to claim 9, wherein at least some of said predetermined unit cells are a tetrahedron, a dodecahedron, or an octahedron.

13. The method according to claim 9, wherein the beam is a laser beam.

14. The method according to claim 9, wherein the beam is an electron beam.

15. The method according to claim 9, wherein said substrate is a base or core made of a metal selected from the group consisting of titanium, titanium alloys, stainless steel, cobalt chrome alloys, tantalum and niobium, and wherein said first layer is fused to said base or core.

16. The method according to claim 15, wherein said base or core is integral with said first layer and imparts additional physical properties to an overall construct.

17. The method according to claim 9, wherein at least some of said predetermined unit cells are truncated to provide a barb effect.

18. The method according to claim 9, wherein said produced three-dimensional porous structure is a spinal component.

19. The method according to claim 9, wherein said metal powder is selected from the group consisting of titanium, titanium alloys, stainless steel, cobalt chrome alloys, tantalum and niobium.

20. The method according to claim 9, wherein said produced three-dimensional porous structure is a tissue in-growth structure.

21. A method of producing a three-dimensional structure comprising the steps of:

depositing a first layer of a metal powder onto a substrate;

scanning a beam having a power (P) for a period of time (μ

sec) with a point distance (μ

m), so as to melt said metal powder at predetermined locations to form a portion of a plurality of predetermined unit cells within said metal powder layer, said predetermined unit cells having a plurality of struts with a length and a cross-section;

depositing at least one additional layer of metal powder onto said first layer;

repeating the step of scanning a beam for at least some of said additional deposited metal powder layers in order to continue forming said predetermined unit cells; and

varying porosity within said three-dimensional structure by at least one of (i) forming a unit cell in one metal powder layer having at least one of (a) a different shape from a unit cell within a successive metal powder layer and (b) at least one strut having a different dimension from a corresponding strut of a unit cell of the same shape within a successive metal powder layer, and ii) applying a random perturbation in any direction to vertices of the unit cells to randomize the geometry of the unit cells.

22. The method according to claim 21, wherein at least some of said struts have a cross-section which is circular or rectangular.

23. The method according to claim 21, wherein some of said struts intersect at a plurality of intersection points, further comprising sintering at least some of said intersection points after at least some of said scanning and depositing steps are completed.

24. The method according to claim 21, wherein during the step of scanning said metal powder layers, said laser beam is adjusted to modify said length of said struts of said predetermined unit cells.

25. The method according to claim 21, wherein at least some of said predetermined unit cells are deformed so as to drape over said substrate.

26. The method according to claim 21, wherein during the step of scanning said metal powder layers, said beam is adjusted to modify said cross-section of said struts of said predetermined unit cells.

27. The method according to claim 21, wherein at least some of said predetermined unit cells are offset from one another to allow at least some struts of said predetermined unit cells to overlap some struts of another predetermined unit cell.

28. The method according to claim 21, wherein at least some of said predetermined unit cells are in the shape of a regular polygon.

29. The method according to claim 21, further comprising prior to scanning said metal powder layer, predetermining a range of porosity for said metal powder layer and adjusting said beam so that said beam scans said metal powder layer to produce a layer of melted metal powder having a porosity within said predetermined range.

30. The method according to claim 29, wherein said beam is adjusted for scanning more than one metal powder layer without having to be adjusted again.

31. The method according to claim 21, wherein said metal powder layers are deposited and scanned in a manner to form a medical implant.

32. The method according to claim 31, further comprising varying said porosity throughout said medical implant to provide soft-tissue characteristics to said medical implant.

33. The method according to claim 21, wherein at least some of said predetermined unit cells have at least one of a shape that is not a regular polygon and a strut that has an irregular cross-sectional shape.

34. The method according to claim 21, wherein the beam is a laser beam.

35. The method according to claim 21, wherein the beam is an electron beam.