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Cutting tool selection based on tool-life testing: An experimental investigation of tool wear when machining wrought and 3D printed Ti6Al4V using coated and un-coated tools
Date
2024-11-30
Abstract
With the advent of additive manufacturing (3D printing) of titanium components in the medical, aerospace, and automotive industries, it is now possible to produce complex geometries with almost total design freedom. However, this design flexibility introduces several considerations, including surface waviness, build angle, and microstructural anisotropy resulting from the additive manufacturing process. Of particular interest is microstructural anisotropy and its impact on the mechanical/chemical properties and machinability of printed components. This anisotropy is influenced by the “angle of build”, i.e., the various angles at which a freeform geometric shape can be printed, such as for hip or femoral implants or similarly shaped parts in medical, aerospace, or automotive applications.
Currently, finish-machining operations on titanium parts printed using selective laser melting (SLM) are performed with the same cutting tools used for finishing wrought titanium components. However, studies indicate that cutting forces for Ti6Al4V components manufactured via SLM can be up to 70% higher than those for wrought counterparts. Additionally, temperatures at the cutting interface of additively manufactured material can exceed those of wrought titanium, significantly impacting tool wear. Surface waviness can cause unequal material engagement with the cutting tool, leading to uneven tool wear. While the criteria for tool wear may be similar for both 3D-printed and wrought titanium materials, the wear rate can differ during machining.
To address these differences, a series of machining tests was conducted to identify deficiencies in the cutting tools currently used for machining 3D-printed titanium. A total of 20 machining tests were performed, with results analyzed using an Alicona Infinite Focus G5 microscope to measure flank wear to a Vbmax of 0.150mm. The cutting tools had a standard geometry, with variations in PVD coatings to improve wear behavior and tool life. Cooling systems (compressed air, LCO2, LCO2 & MQL) were also employed to manage temperature and lubrication at the cutting tool interface. Results show that while current cutting tools from approved vendors perform well on wrought titanium, they perform poorly on 3D-printed titanium, with tool life reduced by up to ten times in terms of the number of passes. Cutting tool solutions provided by vendors and those suggested in the literature for machining 3D-printed titanium are not sufficiently aligned to allow the same tools to be used effectively for both 3D-printed and wrought titanium. This highlights the need for a deeper understanding of cutting tool wear, with the goal of developing improved cutting tool solutions specifically for machining 3D-printed titanium in the future.
Supervisor
Description
Publisher
University of Limerick
Citation
Files
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Downey_2025_Cutting.pdf
Adobe PDF, 13.76 MB
Funding code
Funding Information
Sustainable Development Goals
External Link
Type
Thesis
Rights
http://creativecommons.org/licenses/by-nc-sa/4.0/