The influence of tool geometry, feed rate and machining strategy on hole surface integrity following single-shot drilling of 3 layer metallic-composite stacks

Chun-Liang Kuo, Sein Soo, David Aspinwall, W. Thomas, S. Bradley, D. Pearson, R M'Saoubi, W. Leahy

Research output: Chapter in Book/Report/Conference proceedingConference contribution

34 Downloads (Pure)

Abstract

A full factorial experimental design involving single-shot drilling of 3 layer Ti-6Al-4V/CFRP/Al7050 stack workpieces was performed to evaluate the effect of drill geometry (single and triple margin), feed rate (0.05 and 0.08 mm/rev) and operating strategy (with and without pecking) on burr formation and hole surface integrity. All tests were carried out wet using twin-fluted, coated tungsten carbide drills having a diameter of 6.35 mm. When employing triple margin drills, average hole surface roughness (Ra) values were 2.20, 9.66 and 0.83 μm in the Ti, CFRP and Al sections respectively at test cessation (90 holes). These were 4 times higher for the Ti and Al layers compared to those produced with the single margin geometry. Similarly, an increase in Al entrance and exit burr heights of ~100 and ~430% respectively was observed when employing triple margin drills due to the greater contact area between the tool and workpiece. However no delamination of the CFRP layer was detected in any of the holes machined with the triple margin tools. Cross-sectional microstructures of Ti and Al layers showed plastically deformed regions of up to 184 and 75 µm respectively beneath the machined surface. Corresponding microhardness evaluation of the Ti section showed an increase of up to 60 HK0.025 above the bulk value, to a depth of ~200 µm.
Original languageEnglish
Title of host publicationProceedings of the 30th International Manufacturing Conference (IMC30)
EditorsGerry Byrne, Brid Mullaney, Pat Connolly, Eamonn Ahearne, Naomi Green
PublisherUniversity College Dublin Press
Pages104-113
Number of pages10
ISBN (Print)978-1-90-525475-0
Publication statusPublished - 1 Sep 2013
EventInternational Manufacturing Conference, 30th (IMC30) - University College Dublin, Dublin, Ireland
Duration: 3 Sep 20134 Sep 2013

Conference

ConferenceInternational Manufacturing Conference, 30th (IMC30)
Country/TerritoryIreland
CityDublin
Period3/09/134/09/13

Keywords

  • Ti/CFRP/Al stacks
  • drilling
  • surface integrity

Fingerprint

Dive into the research topics of 'The influence of tool geometry, feed rate and machining strategy on hole surface integrity following single-shot drilling of 3 layer metallic-composite stacks'. Together they form a unique fingerprint.

Cite this