Details
| Original language | English |
|---|---|
| Article number | S29203 |
| Journal | Journal of Laser Applications |
| Volume | 27 |
| Issue number | S2 |
| Publication status | Published - 1 Feb 2015 |
| Event | 33rd International Congress on Applications of Lasers and Electro-Optics, ICALEO 2014 - San Diego, United States Duration: 19 Oct 2014 → 23 Oct 2014 |
Abstract
Cochlear implants (CI) are complex medical implants used as a common therapeutic measure for deaf people who suffer from damage to the inner ear. The success of CI insertion, a manual surgery procedure, is highly dependent on the surgeon's experience. Additionally, more precise positioning of the electrode close to the membrane structures could increase the effectiveness of frequency selectivity and stimulus conduction. To overcome these limitations, the degree of deformation of the electrode during its insertion has to be controllable. This ability can be achieved by integrating micro-actuator elements of a nickel titanium (NiTi) shape memory alloy (SMA) inside the electrode. These elements are manufactured using selective laser micromelting (SLμM). Initially, different concepts of activation mechanisms for SMA actuators for CI electrodes are discussed. Following the rules of additive manufacturing on a microscale, the corresponding actuator design and manufacturing strategies are presented. Suitable SLμM process parameters to achieve high spatial resolution are identified. Due to the high process temperatures, material chemical properties, respectively, its functional behavior, may be affected using SLμM. Therefore, analyses of SLμM NiTi parts manufactured using carrier gas hot extraction as well as differential scanning calorimetry (DSC) are carried out. Force measurements verify the available recovery forces of the produced micro-actuators activated thermally by one way effect. A suitable additive manufacturing strategy that allows the repeatable production of micro-actuators at a resolution of less than 100μm could be evaluated. Different anatomical geometries could be transferred from clinical data model to the manufacturing process. The processed NiTi parts meet the requirements of the ASTM F2063 concerning oxygen inclusion, which is an important condition to preserve shape memory functionality. DSC analyses reflect stable functional properties of the processed NiTi alloy independent of the adjusted laser parameters. Phase transformation of actuators could be actively proved using electrical current and passively using an external heat source.
Keywords
- DSC, medical implants, NiTi, selective laser melting, shape memory alloy
ASJC Scopus subject areas
- Materials Science(all)
- Electronic, Optical and Magnetic Materials
- Physics and Astronomy(all)
- Atomic and Molecular Physics, and Optics
- Engineering(all)
- Biomedical Engineering
- Physics and Astronomy(all)
- Instrumentation
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In: Journal of Laser Applications, Vol. 27, No. S2, S29203, 01.02.2015.
Research output: Contribution to journal › Conference article › Research › peer review
}
TY - JOUR
T1 - Design, processing, and characterization of nickel titanium micro-actuators for medical implants
AU - Hagemann, Ronny
AU - Noelke, Christian
AU - Rau, Thomas
AU - Kaierle, Stefan
AU - Overmeyer, Ludger
AU - Wesling, Volker
AU - Wolkers, Willem Frederik
PY - 2015/2/1
Y1 - 2015/2/1
N2 - Cochlear implants (CI) are complex medical implants used as a common therapeutic measure for deaf people who suffer from damage to the inner ear. The success of CI insertion, a manual surgery procedure, is highly dependent on the surgeon's experience. Additionally, more precise positioning of the electrode close to the membrane structures could increase the effectiveness of frequency selectivity and stimulus conduction. To overcome these limitations, the degree of deformation of the electrode during its insertion has to be controllable. This ability can be achieved by integrating micro-actuator elements of a nickel titanium (NiTi) shape memory alloy (SMA) inside the electrode. These elements are manufactured using selective laser micromelting (SLμM). Initially, different concepts of activation mechanisms for SMA actuators for CI electrodes are discussed. Following the rules of additive manufacturing on a microscale, the corresponding actuator design and manufacturing strategies are presented. Suitable SLμM process parameters to achieve high spatial resolution are identified. Due to the high process temperatures, material chemical properties, respectively, its functional behavior, may be affected using SLμM. Therefore, analyses of SLμM NiTi parts manufactured using carrier gas hot extraction as well as differential scanning calorimetry (DSC) are carried out. Force measurements verify the available recovery forces of the produced micro-actuators activated thermally by one way effect. A suitable additive manufacturing strategy that allows the repeatable production of micro-actuators at a resolution of less than 100μm could be evaluated. Different anatomical geometries could be transferred from clinical data model to the manufacturing process. The processed NiTi parts meet the requirements of the ASTM F2063 concerning oxygen inclusion, which is an important condition to preserve shape memory functionality. DSC analyses reflect stable functional properties of the processed NiTi alloy independent of the adjusted laser parameters. Phase transformation of actuators could be actively proved using electrical current and passively using an external heat source.
AB - Cochlear implants (CI) are complex medical implants used as a common therapeutic measure for deaf people who suffer from damage to the inner ear. The success of CI insertion, a manual surgery procedure, is highly dependent on the surgeon's experience. Additionally, more precise positioning of the electrode close to the membrane structures could increase the effectiveness of frequency selectivity and stimulus conduction. To overcome these limitations, the degree of deformation of the electrode during its insertion has to be controllable. This ability can be achieved by integrating micro-actuator elements of a nickel titanium (NiTi) shape memory alloy (SMA) inside the electrode. These elements are manufactured using selective laser micromelting (SLμM). Initially, different concepts of activation mechanisms for SMA actuators for CI electrodes are discussed. Following the rules of additive manufacturing on a microscale, the corresponding actuator design and manufacturing strategies are presented. Suitable SLμM process parameters to achieve high spatial resolution are identified. Due to the high process temperatures, material chemical properties, respectively, its functional behavior, may be affected using SLμM. Therefore, analyses of SLμM NiTi parts manufactured using carrier gas hot extraction as well as differential scanning calorimetry (DSC) are carried out. Force measurements verify the available recovery forces of the produced micro-actuators activated thermally by one way effect. A suitable additive manufacturing strategy that allows the repeatable production of micro-actuators at a resolution of less than 100μm could be evaluated. Different anatomical geometries could be transferred from clinical data model to the manufacturing process. The processed NiTi parts meet the requirements of the ASTM F2063 concerning oxygen inclusion, which is an important condition to preserve shape memory functionality. DSC analyses reflect stable functional properties of the processed NiTi alloy independent of the adjusted laser parameters. Phase transformation of actuators could be actively proved using electrical current and passively using an external heat source.
KW - DSC
KW - medical implants
KW - NiTi
KW - selective laser melting
KW - shape memory alloy
UR - http://www.scopus.com/inward/record.url?scp=84928205266&partnerID=8YFLogxK
U2 - 10.2351/1.4906381
DO - 10.2351/1.4906381
M3 - Conference article
AN - SCOPUS:84928205266
VL - 27
JO - Journal of Laser Applications
JF - Journal of Laser Applications
SN - 1042-346X
IS - S2
M1 - S29203
T2 - 33rd International Congress on Applications of Lasers and Electro-Optics, ICALEO 2014
Y2 - 19 October 2014 through 23 October 2014
ER -