Browsing by Subject "Tool wear"

Now showing 1 - 3 of 3

Open Access
Energy based investigation of process parameters while drilling carbon fiber reinforced polymers
(Elsevier B.V., 2016) Karpat, Yiğit; Bahtiyar, O.
Carbon fiber reinforced polymers (CFRPs) are widely used in the aerospace industry due to their light weight, high strength, and low thermal conductivity. Drilling is a critical process that affects the quality of CFRP parts. This work studies the influence of process parameters on delamination and tool wear. Polycrystalline diamond helical drills are used in the experiments. It has been shown that drilling energy calculations can be used to set appropriate feed and speed parameters and for increasing drilling performance of CFRPs. The results also indicate the importance of thermal modeling of CFRP laminate for better understanding of the drilling process. © 2016 The Authors.
Open Access
Experimental investigations on micro milling of stavax stainless steel
(Elsevier, 2014) Oliaei, Samad Nadimi Bavil; Karpat, Yiğit
Micro mechanical milling of Stavax (modified AISI 420) stainless steel which is commonly used in the plastic injection molding industry due to its high corrosion resistance, machinability and wear resistance is studied in this paper. The goal of this study is to investigate the influence of process input parameters such as cutting speed, depth of cut, feed per tooth, radial immersion percentage, and plunging method on process outputs during circular pocketing operation. Tool wear, machining forces and surface roughness measurements are considered to identify the relationships between process inputs and outputs. It is observed that plunging method has a significant influence on tool wear which in turn affects micro milling forces and surface quality. The positive impact of micro milling with a pre-drilled hole is demonstrated. The relationship between radial immersion and feed per tooth is shown to be important in terms of tool wear and surface roughness.
Open Access
Influence of tool wear on machining forces and tool deflections during micro milling
(Springer, 2016) Oliaei, S. N. B.; Karpat, Y.
Tool wear on the cutting edges of micro end mills is an important issue affecting process outputs such as tool deflections and surface roughness, especially when difficult-to-cut materials such as titanium alloys, stainless steel, etc. are machined at micro scale. An understanding of the interactions between tool wear, machining forces, tool deflections, and surface roughness is important in order to maintain component quality requirements. However, in literature, the number of studies concerning tool wear in micro end mills is limited. The goal of the paper is to better understand tool wear patterns (flank wear, edge rounding) of micro end mills and their relationship to machining parameters. In this study, first, the influence of tool wear on micro milling forces and surface roughness parameters is analyzed and favorable micro milling process parameters are identified. It is shown that, when machining with worn end mills, forces are affected by the tool wear patterns. Then, the influence of increased milling forces due to tool wear on tool deflections and tool breakage is studied using both experimental techniques and finite element analysis. The finite element model-based tool deflection and tool breakage predictions are validated through experiments. The results of this study can be used in process parameter selection in pocket micro milling operations and tool condition monitoring systems.