Publication: Investigation of tool coated with tetrahedral amorphous carbon nanocomposite for single-shot drilling of cfrp/aluminium stack
| datacite.subject.fos | oecd::Engineering and technology::Mechanical engineering | |
| dc.contributor.author | Jebaratnam Joy Mathavan | |
| dc.date.accessioned | 2025-05-19T02:31:27Z | |
| dc.date.available | 2025-05-19T02:31:27Z | |
| dc.date.issued | 2023-08-01 | |
| dc.description.abstract | Drilling through a composite-metal stack in a single pass is a challenging process, as the drill bit must penetrate through two distinct materials simultaneously. Though tungsten carbide (WC) drill bits are commonly used in this field due to their better performance than high speed steel (HSS) tools and cost effectiveness compared to poly crystalline diamond (PCD) tools, they tend to create defects such as diameter variation, circularity error, surface roughness, delamination and burr formation. To address these issues, this study aims to coat the tungsten carbide drill bits with tetrahedral amorphous carbon (Ta-C) nanocomposite layers such as micro-Ta-C, Ta-C+Cr, and Ta-C+Ti. The holes were drilled using a 4.85 mm diameter twist drill, with a feed rate of 0.05 rev/min and a spindle speed of 2600 rev/min. The Physical Vapor Deposition (PVD) method was used for coating development, and triple rotation was employed to achieve a thin film thickness of 2.5 μm. The micro-Ta-C coating exhibited 28.9% and 53.6% higher maximum bonding strengths and resist 61.37% and 90.47% higher maximum frictional forces than Ta-C+Ti and Ta-C+Cr coatings, respectively. It also had 6.08% higher HV0.005 hardness compared to the uncoated tool. The Ta-C+Cr coating had the lowest coefficient of friction (<0.05), followed by the Ta-C+Ti coating (<0.09). All tools produced an average stack up diameter error below H9 tolerance and hole circularity error below 30 μm. Surface roughness in aluminium panel by all the tools required further improvement. All coated tools achieved better average CFRP surface roughness below 3.2 μm, with Ta-C+Ti coating performing 22.3% better than uncoated tool. Micro-Ta-C and Ta-C+Ti coated tools showed 35.26% and 16.67% better exit delamination, respectively compared to the uncoated tool. The average exit burr height from all tools was below 150 μm, with Ta-C+Cr and Ta-C+Ti coated tools showed 23.93% and 6.45% better burr height results compared to micro-Ta-C coated tools, respectively. Based on coating characterization, experimental results, and process capability six-pack statistical analysis, the Ta-C+Ti coated tool is the preferred choice. | |
| dc.identifier.uri | https://erepo.usm.my/handle/123456789/21681 | |
| dc.language.iso | en | |
| dc.title | Investigation of tool coated with tetrahedral amorphous carbon nanocomposite for single-shot drilling of cfrp/aluminium stack | |
| dc.type | Resource Types::text::thesis::master thesis | |
| dspace.entity.type | Publication | |
| oairecerif.author.affiliation | Universiti Sains Malaysia |