Kühlkanalaustrittsbedingungen bei Bohrern*/Cooling channel outlet conditions for drills. Influence of the cooling channel diameter and second tool orthogonal clearance on the cooling lubricant’s efficiency

Die Kühlschmiereffizienz von innengekühlten Bohrern lässt sich durch eine Optimierung der Kühlkanalaustrittsbedingungen steigern. In dem Beitrag wird der Einfluss des Kühlkanaldurchmessers und des zweiten Freiwinkels auf den Bohrprozess mittels VHM (Vollhartmetall)-Wendelbohrern, welche auf Basis einer numerischen Simulation ausgelegt wurden, experimentell untersucht. Es wird gezeigt, dass im Besonderen der Kühlkanaldurchmesser einen Einfluss auf die Kühlung hat.   The cooling lubricant efficiency of internally cooled drills can be increased by optimizing the cooling channel outlet conditions. In this paper, the influence of the cooling channel diameter and the second tool orthogonal clearance on the drilling process is experimentally investigated using cemented carbide drills based on numerical simulations. It will be shown that the cooling channel diameter in particular has an influence on cooling lubrication.

Determination of Surface and Hole Quality in Drilling of AISI D2 Cold Work Tool Steel Using MPMR, MARS and LSSVM

This paper adopts Minimax Probability Machine Regression (MPMR), Multivariate Adaptive Regression Spline (MARS), and Least Square Support Vector Machine (LSSVM) for prediction of surface and hole quality in drilling of AISI D2 cold work tool steel with uncoated titanium nitride (TiN) and titanium aluminum nitride (TiAlN) monolayer- and TiAlN/TiN multilayer-coated-cemented carbide drills. MPMR is a probabilistic model. MARS is a nonparametric regression technique. LSSVM is developed based on statistical learning algorithm. Cutting tool (t), Feed rate (fr)(mm/rev), and Cutting speed (v)(m/min) have been adopted as inputs of MPMR, MARS, and LSSVM. The output of MPMR, MARS, and LSSVM is Surface roughness (rs) (μm) and Roundness error (re) (μm). A comparative study has been presented between the developed models. The results show that the developed model gives excellent performance.

Drilling of CFRP/Ti6Al4V Stack Board

Drilling experiments with a CFRP/Ti6Al4V stack board were carried out using a TiAlN-coated cemented carbide drill, TiAlCr/TiSi-coated cemented carbide drill, and TiSiN-coated cemented carbide drill. Cutting experiments were carried out under a dry cutting process and water-mist-cooling process. Themain results obtained were as follows. The tool life of the TiAlCr/TiSi-coated cemented carbide drill was the longest among the three coated cemented carbide drills. The tool life under the water-mist-cooling process was longer than that under the dry process. Because the titanium alloy chips were much harder under the water-mist-cooling process, the cutting torque under this process became larger with an increase in tool flank wear compared to that under the dry process.

Experimental Studies for Burrs in Dry Drilling of Stacked Metal Materials

During the drilling of stacked materials, burrs forming on both the surface layer and the interlayer have some undesirable characters with regard to assembly quality, and deburring is a time-consuming and costly operation. This paper presented an experimental study on dry drilling of Ti-6Al-4V titanium alloy and 7075-T6 aluminium alloy stacked materials, which was performed by using uncoated cemented carbide drills. The burr size was evaluated at various spindle speeds, feed rates, stacking sequence and clamp force. Finally, the burr morphology was observed and analyzed. The best process parameters recorded in this paper were at the spindle speed of 2000r/min, the feed rate of 0.075mm/r, the pressure of 0.3MPa and the stacking sequence of the Ti-6Al-4V titanium alloy on top of the 7075-T6 aluminium alloy.