Experimental and Simulation Study on Tool Life Models in Drilling of Forging Brass Using Uncoated-WC and AlCrN Coated-WC Tools

Abstract

Burr is an undesirable phenomenon occurring in drilling operation which is one of the essential operations in the machining industry since it is directly influencing the operating costs. Exit burr height (EBH) values as the function of drilling time during drilling the specific holes of the forging brass workpieces used for producing the water-valve components with the uncoatedtungsten carbide (WC) and the AlCrN coated-WC drills were discussed. The data sets of drilling time, corresponding to EBH values at the appropriate criterion were used to develop the tool life models in terms of cutting speed and feed rate using Taylor's equation. Monte Carlo simulation was adopted to study the uncertainty of cutting speed and feed rate on tool life predictions for sensitivity analysis. The results showed that drilling with a low feed rate decreased the averages of EBH. The predicted tool life values of the AlCrN coated-WC drills were higher than those of the uncoated-WC ones based on the results of tool life predictions. The appropriate operating condition of the cutting speed of 60 m/min and the feed rate of 0.2 mm/rev was recommended for manufacturers in the drilling of the forging brass workpieces using the AlCrN coated-WC drills. Moreover, the predicted tool life values for the uncoated-WC and the AlCrN coated-WC drills were about 600 and 800 min, respectively. This indicated that the AlCrN coated-WC drill increased tool life by 30%.

Simulation of the influence of cutting speed and feed rate on tool life in hard turning of AISI 4140 steel

“…They stated that the bearing replacement strategy contributed a simple approach to significantly improving system reliability and achievement through less downtime and higher cost savings. Timata and Saikaew [13] studied the sensitivity of cutting speed and feed rate to tool life prediction in tool life evaluation by adopting an MCS based on Taylor's tool life equation.…”

“…This indicated that chip surface chromaticity was used to predict tool wear based on the development of Taylor's tool life equation during the cutting of stainless steel (2316ISO-B MOD) with a TiAlN coated insert. In a drilling operation, the tool life equation was utilized to create a relationship between tool life and cutting speed and feed rate during machining of forging brass with uncoated tungsten carbide (WC) and AlCrN-coated WC tools using the criterion of exit burr height of 0.16 mm [13]. Kovac et al [14] also proposed an extended Taylor's functional relationship between tool life and cutting speed, feed per tooth, and depth of cut through measurements of tool-workpiece thermocouple temperature during milling of AISI 1060 steel with a carbide insert of 125 mm in diameter.…”