Efficient Machining of Microdimples for Friction Reduction

Denkena, Berend; Köhler, Jens; Kästner, J.; Göttsching, T.; Dinkelacker, F.; Ulmer, Hubertus

doi:10.1115/1.4023757

Cited by 20 publications

(10 citation statements)

References 12 publications

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“…Furthermore, if the application of a specific structure/pattern on the articulating surfaces has been shown to improve macro lubrication [31,38], and this also warrants further investigation with the materials and testing methods used in the present study.…”

Section: Discussionmentioning

confidence: 99%

Manufacturing conditioned roughness and wear of biomedical oxide ceramics for all-ceramic knee implants

Turger

Köhler

Denkena

et al. 2013

BioMedical Engineering OnLine

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BackgroundCeramic materials are used in a growing proportion of hip joint prostheses due to their wear resistance and biocompatibility properties. However, ceramics have not been applied successfully in total knee joint endoprostheses to date. One reason for this is that with strict surface quality requirements, there are significant challenges with regard to machining. High-toughness bioceramics can only be machined by grinding and polishing processes. The aim of this study was to develop an automated process chain for the manufacturing of an all-ceramic knee implant.MethodsA five-axis machining process was developed for all-ceramic implant components. These components were used in an investigation of the influence of surface conformity on wear behavior under simplified knee joint motion.ResultsThe implant components showed considerably reduced wear compared to conventional material combinations. Contact area resulting from a variety of component surface shapes, with a variety of levels of surface conformity, greatly influenced wear rate.ConclusionsIt is possible to realize an all-ceramic knee endoprosthesis device, with a precise and affordable manufacturing process. The shape accuracy of the component surfaces, as specified by the design and achieved during the manufacturing process, has a substantial influence on the wear behavior of the prosthesis. This result, if corroborated by results with a greater sample size, is likely to influence the design parameters of such devices.

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Section: Discussionmentioning

confidence: 99%

Manufacturing conditioned roughness and wear of biomedical oxide ceramics for all-ceramic knee implants

Turger

Köhler

Denkena

et al. 2013

BioMedical Engineering OnLine

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“…Previous investigations using honed cylinder liners that were equipped with a suitable arrangement of micro dimples proved the potential for friction reduction [12]. The results shown in Fig.…”

Section: Introductionmentioning

confidence: 90%

Controlled Turning Process for the Production of Friction-Reduced Cylinder Liners with a Defined Free-Form Geometry

Denkena¹,

Bergmann²,

Handrup³

et al. 2021

Journal of Machine Engineering

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Friction in the piston-cylinder system of combustion engines has a great influence on fuel consumption. To reduce the friction of combustion engines, free-form cylinder liners and microstructured cylinder liners have proven to be advantageous. However, the combination of both processes is not industrially realized today because of an increased manufacturing effort due to a higher number of process steps. To save resources in form of honing oil in the production, the free-form can be machined by a dry turning process instead of form honing. A combination with the microstructuring process in a single manufacturing step would furthermore reduce nonproductive time. This paper presents a piezo-actuated hybrid tool that can carry out both processes. The tool wear and the behavior during free-form fine machining of cylinder liners are investigated. A process control system is introduced that controls the cylinder liner geometry by adapting the process parameters during free-form turning.

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“…Micro-milling [4], micro-EDM (electric discharge-machining) [5] and laser machining [6] were reliable means to fabricate these micro-punches. However, with reduction of the product size, the leading time for production significantly increased in those traditional approaches.…”

Section: Introductionmentioning

confidence: 99%

Plasma Nitriding-Assisted Printing of Stainless Steel Punches for Micro-piercing Process

Aizawa¹,

Shiratori²

2017

JMEA

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MEMS (micro-electric-mechanical-system) required for miniature, thin mechanical parts as a structural member; e.g., the miniature pumping system consisted of ten to twelve thin metallic plates before joining. At present, those thin shaped sheets were fabricated by the chemical etching. Their geometric inaccuracy as well as long leading time often became an engineering issue. Micro-piercing process was expected to make mass production of thin sheet products with complex and accurate geometry for much shorter leading time once the die for this micro-piercing was built in. In the present paper, a new plasma nitriding-assisted printing was proposed as an automatic production line to fabricate the micro-piercing punch. After preparation of CAD-data of the punch head, its two dimensional geometry was ink-jet printed directly on the AISI420 stainless steel die-substrate. The unprinted surface area was only plasma nitrided at 693 K for 14.4 ks to transform this two dimensional micro-pattern to the three dimensional hardness distribution in the AISI420 substrate. Through the mechanical removal of ink-jet printed area, the flat punch head with sharp edge corners was fabricated in much shorter duration time than the end-milling. SEM-EDX, surface profiling measurement as well as micro-hardness testing were employed to describe each step in the above plasma printing. The thin MEMS stainless steel part with a micro-pendulum as well as three S-letter shaped springs was taken for an example to describe this automatic production procedure of plasma printing from the CAD data mining to the micro-piercing punch finishing.

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Efficient Machining of Microdimples for Friction Reduction

Cited by 20 publications

References 12 publications

Manufacturing conditioned roughness and wear of biomedical oxide ceramics for all-ceramic knee implants

Manufacturing conditioned roughness and wear of biomedical oxide ceramics for all-ceramic knee implants

Controlled Turning Process for the Production of Friction-Reduced Cylinder Liners with a Defined Free-Form Geometry

Plasma Nitriding-Assisted Printing of Stainless Steel Punches for Micro-piercing Process

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