Thesis
Effect of tool geometry on cutting mechanism and hole quality when drilling carbon fiber reinforced (CFRP) composites
Washington State University
Master of Science (MS), Washington State University
05/2015
Handle:
https://hdl.handle.net/2376/101943
Abstract
The demand for carbon fiber reinforced polymers (CFRP) in aerospace industries has increasingly risen over the past years. CFRP composites are often mechanically joined to the structures or other metals using bolts and rivets. Acquiring high quality holes is essential to manufacturing process in order to get precise and damage-free holes and facilitate assembly procedure without rework. When it comes to the drilling process of CFRP, some of the issues related to hole quality include hole size errors, form defects such as delamination, fiber pull-outs, and defects due to temperature rise. Fiber pull-outs are one of most common hole surface damages when drilling CFRP plates, which has not been analyzed extensively. This study aims to investigate the effect of cutting conditions and tool geometry on CFRP hole quality. The experiments were carried out using four drill geometries at different machining conditions (feed and speed combination) on a quasi-isotropic CFRP plate. Drilling forces were studied and quality of the holes was evaluated with respect to hole size, cylindricity, roundness, and surface roughness. The fiber pull-out area and depth were also quantified with respect to the interaction angle of the tool and fiber directions (the tool-fiber angle). The results revealed that the fiber pullouts occurred at the regions with specific tool-fiber angles (160 to 135degrees). Results revealed that tools with lower rake angle produce deeper fiber pull outs. The maximum drilling tool temperature occurs when the drill exits the plate and it is influenced mostly by feed rate or tool-workpiece engagement time. The results allow customization of the machining processes to minimize, predict and mitigate the occurrence of fiber pull-outs and other damages when drilling composites.
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Details
- Title
- Effect of tool geometry on cutting mechanism and hole quality when drilling carbon fiber reinforced (CFRP) composites
- Creators
- Sina Alizadeh Ashrafi
- Contributors
- Dave Kim (Chair)Stephen Solovitz (Committee Member) - Washington State University, Engineering and Computer Science (VANC), School ofYoon Jo Kim (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Electrical Engineering and Computer Science, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Number of pages
- 127
- Identifiers
- 99900525018701842
- Language
- English
- Resource Type
- Thesis