Surface Finish Machining of Medical Parts Using Plasma Electrolytic Polishing

Zeidler, Henning; Boettger-Hiller, Falko; Edelmann, Jan; Schubert, Andreas

doi:10.1016/j.procir.2015.07.038

Cited by 73 publications

(37 citation statements)

References 6 publications

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“…Henceforth, the surface roughness of the fabricated cranial implant in this study was also measured (Ra = 25.3 µm) and found within the specified range. However, if needed, the EBM built cranial implant can be post-processed for better surface finish using plasma electro polishing [45] and laser ablation techniques [46,47].…”

Section: Fabricationmentioning

confidence: 99%

Fabrication and Analysis of a Ti6Al4V Implant for Cranial Restoration

et al. 2019

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A custom made implant is critical in cranioplasty to cushion and restore intracranial anatomy, as well as to recover the appearance and attain cognitive stability in the patient. The utilization of customized titanium alloy implants using three-dimensional (3D) reconstruction technique and fabricated using Electron Beam Melting (EBM) has gained significant recognition in recent years, owing to their convenience and effectiveness. Besides, the conventional technique or the extant practice of transforming the standard plates is unreliable, arduous and tedious. As a result, this work aims to produce a customized cranial implant using 3D reconstruction that is reliable in terms of fitting accuracy, appearance, mechanical strength, and consistent material composition. A well-defined methodology initiating from EBM fabrication to final validation has been outlined in this work. The custom design of the implant was carried out by mirror reconstruction of the skull's defective region, acquired through computer tomography. The design of the customized implant was then analyzed for mechanical stresses by applying finite element analysis. Consequently, the 3D model of the implant was fabricated from Ti6Al4V ELI powder with a thickness of 1.76-2 mm. Different tests were employed to evaluate the bio-mechanical stability and strength of the fabricated customized implant design. A 3D comparison study was performed to ensure there was anatomical accuracy, as well as to maintain gratifying aesthetics. The bio-mechanical analysis results revealed that the maximum Von Mises stress (2.5 MPa), strain distribution (1.49 × 10 −4 ) and deformation (3.26 × 10 −6 mm) were significantly low in magnitude, thus proving the implant load resistance ability. The average yield and tensile strengths for the fabricated Ti6Al4V ELI EBM specimen were found to be 825 MPa and 880 MPa, respectively, which were well over the prescribed strength for Ti6Al4V ELI implant material. The hardness study also resulted in an acceptable outcome within the acceptable range of 30-35 HRC. Certainly, the chemical composition of the fabricated EBM specimen was intact as established in EDX analysis. The weight of the cranial implant (128 grams) was also in agreement with substituted defected bone portion, ruling out any stress shielding effect. With the proposed approach, the anatomy of the cranium deformities can be retrieved effectively and efficiently. The implementation of 3D reconstruction techniques can conveniently reduce tedious alterations in the implant design and subsequent errors. It can be a valuable and reliable approach to enhance implant fitting, stability, and strength. stability in the patient [2]. Cranial restoration is generally carried out on patients who suffer from head trauma as a result of any injury (accident), infection or congenital deformities [3]. The skull injuries or malformation are considered as one of the most critical and worrying health concerns, which affects a large population all over the world [4]. Moreover, the repairing of cra...

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Section: Fabricationmentioning

confidence: 99%

Fabrication and Analysis of a Ti6Al4V Implant for Cranial Restoration

et al. 2019

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“…After the gas explosion the plasma channel collapses. A characteristic property of the plasma polishing process is a current density J EPP of approximately 0.2 A cm −2 [8]. After the EPP a cleaning process is recommended to remove electrolyte residues.…”

Section: Materials Removal During the Epp According To The Streamer Thmentioning

confidence: 99%

“…Therefore, the need for techniques that improve the surface quality of metal workpieces such as copper [1,2], stainless steel [3][4][5], titanium [6] and metalized carbon fibers [7] is becoming increasingly important in many industrial (chemical and food industry) and medical applications [8,9]. A change in the surface quality can be obtained by various machining methods, including polishing, coating and cutting processes.…”

Section: Introductionmentioning

confidence: 99%

Electrolytic Plasma Polishing of Pipe Inner Surfaces

Cornelsen

Deutsch

Seitz

2017

Metals

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Smooth surfaces are becoming increasingly important in many industries, such as medical, chemical or food. In some industrial areas, the mechanical treatment of surfaces (grinding and polishing) does not fulfil desired specifications. Non-abrasive methods (chemical and electrochemical) have the advantage that even complex geometries and free-form shapes can be polished. In the context of this paper, electrochemical surface treatment is considered in more detail. Both electro polishing, which is state of the art, and the novel electrolytic plasma polishing (EPP) process are presented. This paper focusses on the electrolytic plasma polishing because it has many advantages compared to the process of electro polishing. The theoretical operation of the electrolytic plasma polishing is shown. A prototype system for plasma polishing of internal surfaces of pipes was installed and a polishing head was developed. Several parameters are investigated, such as the width of the adjustable polishing head gap and different velocities v or different applied potential differences U, and first results of the average surface roughness Sa as function of the various parameters were evaluated. It can be seen that a stable polishing process can be achieved at the highest potential difference of 320 V and that the average surface roughness Sa reaches a range from 0.065 to 0.090 µm. At the same time, it has been shown that with increasing potential difference, the average surface roughness becomes independent of the width of the adjustable polishing head gap.

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“…In contrast to electropolishing, PeP also operates using nontoxic electrolytes, which is favourable considering AM applications in medical contexts. It could be shown that PeP does not act cytotoxic but slows down bacteria growth [8].…”

Section: Pep Of Am Partsmentioning

confidence: 99%

Surface Finish of Additively Manufactured Parts using Plasma Electrolytic Polishing

Henning¹,

Böttger‐Hiller²

2018

WCMNM 2018 World Congress on Micro and Nano Manufacturing

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Additive manufacturing (AM) is considered a disruptive or key enabling technology. Polymer based AM using filament extrusion has attracted much attention from customer/maker side, but many industrial applications require parts made in metallic materials and consequently powder based processes. While these AM (SLM, EBM, DMD) processes become more and more reliable and the achievable accuracy shifts towards industrial applicability, the achievable surface quality is still insufficient. This process inherent challenge is based on partial melting and/or agglomeration of powder to the outside of the melt pool and the part, leading to high roughness values in the range of 10 µm ≤ Ra ≤ 30 µm. In combination with AM-specific complex designs (i.e. "complexity for free" approach) and the resulting inaccessibility of many surfaces for e.g. grinding tools, surface finishing to acceptable values of Ra ≤ 2 µm is difficult. The recently developed Plasma electrolytic Polishing (PeP) process is based on a high DC voltage applied between part and an aqueous electrolyte and the following creation of a plasma hull. Here, electrochemical and plasma reactions take place. It does not require any shaped tool and has the capability of achieving surface quality of Ra ≤ 0.02 µm when starting from milled parts. However, due to its current-density based localisation towards micro peaks, it is currently not efficient in removing large waviness. As it is shown, PeP is a suitable process to finish-machine AM parts and contributes to a tight tolerance chain, allowing to push AM of complex metal parts further towards general industrial use.Additive Manufacturing, Plasma electrolytic Polishing, surface quality, surface integrity

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Surface Finish Machining of Medical Parts Using Plasma Electrolytic Polishing

Cited by 73 publications

References 6 publications

Fabrication and Analysis of a Ti6Al4V Implant for Cranial Restoration

Fabrication and Analysis of a Ti6Al4V Implant for Cranial Restoration

Electrolytic Plasma Polishing of Pipe Inner Surfaces

Surface Finish of Additively Manufactured Parts using Plasma Electrolytic Polishing

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