uu.seUppsala University Publications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Survey of damage mechanisms on PVD coated HSS hobs used in Swedish gear manufacturing industry
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences. (Tribomaterial, Tribomaterials group)
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences. (Tribomaterial, Tribomaterials group)
2011 (English)In: Tribologia, ISSN 0780-2285, Vol. 30, no 1-2, 37-50 p.Article in journal (Refereed) Published
Abstract [en]

Gear hobbing is widely used for production of cylindrical gears in the Swedish transmission industry. The hob, usually consisting of a homogenous HSS (High Speed Steel) body coated with a ceramic PVD (Physical Vapour Deposition) coating, is designed for regrinding and recoating several times without affecting its cutting geometries. Efficient usage of the tool, considering production costs and gear quality, requires reconditioning before wear starts to affect the gear quality negatively and certainly before tool wear renders reconditioning impossible. Hobs of today generally lack in reliability, making it difficult to judge when they have to be taken out for reconditioning.

 

This work presents a survey of wear as observed on today’s state of the art hobs used by Swedish gear manufactures. It aims to identify damage mechanisms and the common problems in order to enable future production of more reliable hobs. The tools were temporarily borrowed from the production and the analyses were made non-destructively using optical microscopes. This was complemented by destructive cross-sectional analysis on two of the hobs.

 

Wear was most commonly located on the rake faces and the cutting edges of the cutting teeth. It mainly propagates by discrete fractures which appear to originate at local defects in the coating or at the interface. High intrinsic stress in the coating likely promotes coating spallation and accelerates the wear of the cutting edge.

Place, publisher, year, edition, pages
2011. Vol. 30, no 1-2, 37-50 p.
Keyword [en]
gear hobbing, hob, wear, HSS, cutting tool, PVD
National Category
Engineering and Technology
Research subject
Engineering Science with specialization in Tribo Materials
Identifiers
URN: urn:nbn:se:uu:diva-165817OAI: oai:DiVA.org:uu-165817DiVA: diva2:474881
Available from: 2012-01-10 Created: 2012-01-10 Last updated: 2016-04-19Bibliographically approved
In thesis
1. Tribology at the Cutting Edge: A Study of Material Transfer and Damage Mechanisms in Metal Cutting
Open this publication in new window or tab >>Tribology at the Cutting Edge: A Study of Material Transfer and Damage Mechanisms in Metal Cutting
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The vision of this thesis is to improve the metal cutting process, with emphasis on the cutting tool, to enable stable and economical industrial production while using expensive tools such as hobs. The aim is to increase the tribological understanding of the mechanisms operating at a cutting edge and of how these can be controlled using different tool parameters. Such understanding will facilitate the development and implementation of future, tribologically designed, cutting tools.

Common wear and failure mechanisms in gear hobbing have been identified and focused studies of the material transferred to the tool, in both metal cutting operations and in simplified tribological tests, have been conducted. Interactions between residual stresses in the tool coating and the shape of the cutting edge have also been studied.

It was concluded that tool failure is often initiated via small defects in the coated tool system, and it is necessary to eliminate, or minimize, these defects in order to manufacture more reliable and efficient gear cutting tools. Furthermore, the geometry of a cutting edge should be optimized with the residual stress state in the coating, in mind. The interaction between a compressive stress and the geometry of the cutting edge will affect the stress state at the cutting edge and thus affect the practical toughness and the wear resistance of the coating in that area.

An intermittent sliding contact test is presented and shown to be of high relevance for studying the interaction between the tool rake face and the chip in milling. It was also demonstrated that material transfer, that can have large effects on the cutting performance, commences already after very short contact times. The nature of the transfer may differ in different areas on the tool. It may include glassy layers, with accumulations of specific elements from the workpiece, and transfer of steel in more or less oxidized form. Both tool coating material, its surface roughness, and the relative speed between the tool surface and the chip, may influence the extent to which the different transfer will occur.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2012. 77 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 988
Keyword
Tribology, Metal cutting, Gear hobbing, Wear, Coating, Residual stress, Material transfer, Steel
National Category
Engineering and Technology
Research subject
Engineering Science with specialization in Tribo Materials
Identifiers
urn:nbn:se:uu:diva-183186 (URN)978-91-554-8514-6 (ISBN)
Public defence
2012-12-07, 2005, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 10:15 (Swedish)
Supervisors
Available from: 2012-11-16 Created: 2012-10-23 Last updated: 2013-01-23Bibliographically approved

Open Access in DiVA

No full text

Authority records BETA

Gerth, JuliaUrban, Wiklund

Search in DiVA

By author/editor
Gerth, JuliaUrban, Wiklund
By organisation
Applied Materials Sciences
Engineering and Technology

Search outside of DiVA

GoogleGoogle Scholar

urn-nbn

Altmetric score

urn-nbn
Total: 1042 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf