The popularity of additive manufacturing in the medical device manufacturing industry is growing thanks to the ability to print solid substrate and lattice structure for implant fixation in a single step. Printing a lattice structure is not only a matter of design, but it also requires the ability to process the foam-like structure in a way that make it usable in the human body. Cleaning, in this specific case, removes loose particles and/or contaminants from such structures. To achieve this objective, a mechanical and dry step has been developed to remove the majority of loose particles without adding any substance to the lattice structure. Following steps based on chemical etching of the titanium surface on a lattice structure can be used to remove the remaining particles and to modify the structures’ surfaces to enhance osteoconductivity. Where machining lubricants must be removed, we are seeing promising results in developing a proper cleaning step with specific detergents, which avoids any detectable residual in the foam but is capable of completely removing contaminants.

2. Mukesh Kumar
Global Technology Director
Business confidential 2
Cleaning and Surface Modification
of Orthopedic Implants
made via Additive Manufacturing

3. What does the Orthopedic Industry do
In the business of alleviating pain
and restoring mobility
by replacing damaged bone (and cartilage) with
metallic (and plastic) Implants that
− Must survive in vivo for years (10+ years)
− In a hostile (corrosive) environment (in vivo)
− (osseo) integrate with the surrounding bone to
transmit 5-8 X body weight
− Function under fatigue conditions
− Restore Mechanical Alignment

4. A lot to do with Porous Structure
• Why do we need this porous structure
− Bone – Implant Interface
− Transmit load
Animal Studies
Human
Retrieval Analysis

5. Additive Manufacturing in Orthopedics:
Why?
• The need for a Bone Ingrowth Surface
− Which is usually porous (or at least roughened)
− May be
− “mathematically generated” or
− Organic shaped (Biomimetic)
AM in Orthopedics is gaining traction because
AM can build the Solid and Porous region simultaneously &
consistently
without concern of line of sight (e.g. cutting tool
movement)
Eliminate the need for a secondary operation of Coating etc.

6. Business confidential
MANUFACTURING FLOW
Printer
(manufacturing step)
Furnace
Cut from starting
plate
CNC machining
Post processing (ex.:
coating or surface
modification)
AM OPERATOR
Design (customer/tech dept)
Final cleaning
Cleaning from
residual powder
Final controls
Customized packaging In process controls after each step

7. Powder Characteristics
Check raw material properties (incoming inspection)
Check raw material processability
Check printed material properties (tensile test)
Process Monitor
Validated equipment
Validated powder ageing
Daily verification of log files
Periodic verification of energy source power
Periodic maintenance and verification of the calibration of the optical path
Product Verification
Dimensional verification
Microscopic lattice observation
Destructive test on dummy parts to check lattice properties
Destructive test on dummy parts to check material properties
PROCESS MONITORING
Business confidential

8. Design of an efficient process:
 Benefits over costs optimization
Design for Additive Manufacturing:
 Over a decade of experience in
exploiting peculiarities of technology
(e.g., undercuts design, light
structures etc.)
 Design optimization for helping parts
printing (Support strategy,
orientation…)
EASE OF MANUFACTURING
Business confidential
PROPERTY OF A CUSTOMER

9. 9
How Surface Dynamics sees the AM process
AM – Surface Dynamics style
 Advanced manufacturing process;
there is no «magic» inside
 Suitable for serial production and
not only for prototyping or small
series
 Need of having it under control
 Need to understand it and be able
to manipulate it
 AM is just a part of a wider
manufacturing flow
 Scientific approach
 Continuous R&D activities
 Continuous training of engineers and
operators
 Continuous technology update to stay “on
the edge”
 Equipment and process validation
 Raw material incoming inspection with
narrow specifications
 No powder mixing
 Machine dedicated to a single material
 Co-design of the whole process with
customer – DFAM
 Oriented on serial continuous production
MORE THAN 50K IMPLANTABLE
DEVICES SUCCESSFULLY PRINTED
EACH YEAR
Business confidential

10. Technical Considerations for Additive Manufactured Medical
Devices
Guidance for Industry and Food and Drug Administration Staff
Document issued on December 5, 2017.
• Manufacturing material removal processes (cleaning) should
ensure that residues are removed to the level where they do
not impact the safety or effectiveness of the product (see
Section VI.E Removing Manufacturing Material Residues and
Sterilization)
• additively manufactured devices are expected to increase the
difficulty in removing manufacturing material residues
(cleaning) and in sterilization due to the likelihood of increased
surface area, generation of extensive tortuous pathways,
and creation of internal voids with limited or no access.
FDA and Additive Manufacturing
Business confidential 10

11. • Porous Structure
− Development Engineers + Biomaterials Scientists
− Organic Shaped (Biomimetic) or Lattice (ordered) shaped
• Raw Materials
− Size of powder
• Energy Source
− Laser Based followed by heat treatment
− Electron Beam in Heated Chamber (~750C)
Porous Structure
Design, Raw Materials and Technology
Business confidential 11
Tortuosity is better
for biological fixation
Larger the particles, the
harder it is to remove from
porous structure
Incipient Sintering at elevated
temperatures leads to clustering
i.e. increased “effective size”

12. Experience in design of lattice structure suitable
for 3D printing using specific software developed
for this technology
Process and melting strategy specific
for lattice structure (DFAM):
 Selection of the most effective laser path
 Know how of the effects of the key parameters
on the melted material
 Optimization of the component design to
match with the specific melting strategy
POROUS STRUCTURES
ENGINEERED FOR AM
Business confidential

13. Cleaning process
Target
• Get different surfaces finishing on
the same part
• Roughness – reduce if needed
• Remove loose particles
• Preserve the lattice structure
• Leave the part clean
• Must use mass production
process(es)

14. • “Cleaning” step(s) to remove weak particles
• Wet and Dry
• Mechanical process to reduce roughness
• Parameters are determined by DOE
• Initial cleaning step in dry condition
• Possible chemical/mechanical smoothing of
lattice struts surface
• Possible tumbling with proper selection of
abrasive agent (shape and chemistry) to have
smooth substrate surfaces
• Final cleaning customized to remove
residuals without modification of the substrate
Cleaning/surface finishing processes
Approach
Solution
0.00%
0.01%
0.02%
0.03%
0.04%
0.05%
0 1 2 3
massloss%
number of cycles
dry cleaning a dry cleaning b
wet cleaning c wet cleaning d

15. Original surface - Ra≈20µm
Treatment step 1 - Ra≈8µm
Treatment step 2 Ra<2µm
Advanced treatment Ra<1µm
Finishing: macroscopic/surface effect

16. Mechanical
Chemical (may be used also to apply functional features to the surface)
Lattice
• Several different kinds of lattice structures with different pore size, strut
shape and geometry
• Wide range of possibility depending on the desired target

17. Lattice: cleaning effect
Original state after printing and finishing: some
particles sticking on the surface and processing
residuals
Just after cleaning: remaining particles
are well attached to the substrate, no
more process residuals
Possible additional
processing to further
modify the surface

18. 18
Post AM treatments
CaP coating
Coatings, Calcium Phosphate based, can be applied (Eurocoating
processes) to modify the struts surface morphology and chemical
nature
CaP coatings used:
Hydroxyapatite (HA)
Brushite (BR)
Untreated HA coated BR coated

19. 19
Post AM treatments
Surface modification
Business confidential
• Electrochemical surface modification
 Enhance osteointegration
 Can act as antibacterial treatment (doped)

20. Business confidential 20
THANK YOU FOR YOUR ATTENTION
Surface Dynamics Memphis
3110 Stage Post Drive, Suite 101
38133 Bartlett, TN, USA
tel. +1 (901) 326 0168
fax +1 (901) 377 6688
Surface Dynamics Cincinnati
231 Northland Blvd.
45246 Cincinnati, OH, USA
tel. +1 (513) 772 6635
fax +1 (513) 772 0825
info@sdbiocoatings.com
www.sdbiocoatings.com
Eurocoating SpA
Via al Dos de la Roda, 60
38057 Pergine Valsugana, Trento,
Italy
tel. +39 0461 538901
fax +39 0461 518902
info@eurocoating.it
www.eurocoating.it
Anteco Srl
Via Maestri del Lavoro, Lotto D
29,
Loc. Pezzagrande
I 84025 Eboli, Salerno, Italy
Tel.: +39 0828 366156
fax.: + 39 0828 364 802
@PEC: antecosrl@pec.antecobio.it
Eurocoating Medical
Technology (Wuxi) Co., LTD
30 Wanquan Road, Yunlin, Xishan
District
214192 Wuxi, Jiangsu, China
tel. +86 158 6246 7089
www.eurocoating.cn