*Investigation of Drilling Temperature Rise and Thrust Forces in Relation to Machining Conditions and Drilling Depth*

Charbel Y. Seif, American University of Beirut, Mechanical Engineering Department, P.O. Box 11-0236, Riad El-Solh, Beirut 1107 2020, Lebanon, Email: cys02@mail.aub.edu

Ilige S. Hage, Notre Dame University , Mechanical Engineering Department, P.O.Box: 72, ZOUK , Zouk Mosbeh, Lebanon, Email: ilige.hage@ndu.edu.lb

Ahmad M. Baydoun, American University of Beirut, Mechanical Engineering Department, P.O. Box 11-0236, Riad El-Solh, Beirut 1107 2020, Lebanon, Email: amb52@mail.aub.edu  

Ramsey F. Hamade, American University of Beirut, Mechanical Engineering Department, P.O. Box 11-0236, Riad El-Solh, Beirut 1107 2020, Lebanon, Email: rh13@aub.edu.lb

 

 

 

Abstract: Controlling drilling temperature and thrust forces play a significant role in reducing tool wear and improving machining efficiency.  In this work, drilling experiments are setup to measure flank surface temperature via thermocouple sensor wires passed through the coolant holes of 10mm twist drill and brazed to the drill flank surface. The testing involves an inverted drilling set up where the workpiece (Aluminum 6061-T6 rod) is chucked into the spindle of a vertical machining center. The drill is in an inverted static position, secured to a fixed plate dynamometer, and attached to the CNC working table. The drill is positioned aligned with the rotating workpiece centerline. Thrust forces are co-measured using Kistler type 3-component plate dynamometer (type 9254). Flank temperature and machining forces data are collected at sampling rate of 3000 Hz. Test matrix used spindle speed range from 796 to 9868 rpm and feed rate from 0.04 to 0.64 mm/rev. A design of experiment (DOE) using JMP-SAS/STAT® was adopted for selecting combinations of cutting speed and feed rates that cover the investigated machining range. Each experiment is repeated twice while the drilling depth is fixed at 40mm (4 times drill diameter). Temperature and force measuring instruments are calibrated before each drilling experiment.

In line with the literature, drilling temperature and thrust forces are found to increase with cutting conditions of feed (f), maximum cutting speed (V), and drilling depth (Dp). Nonlinear regression analysis produced correlating equations of flank temperature and thrust forces to conditions and follow mechanistic power law of the form a~1~f^a~2~^V^a~3~^Dp^a~4~^  where a~1~, a~2~, a~3~ and a~4~ are identified via fitting by the regression tool. Model parameters are found based on 55 experimental observations at a set convergence criterion of 10^-15^ with a total of 150 iterations. The found operating temperature rise and thrust force equations predict well the data (p-value\<0.05). These equations estimate the drilling flank surface temperature and thrust forces encountered function of the increase in drilling feed rate, cutting speed, and drilling depth. They may be used by machinists to save time for selecting optimal drilling conditions that minimize tool wear by accounting for operating drilling flank temperature thrust force effects.


Investigation of Drilling Temperature in Relation to Machining Conditions and Cutting Time

Division / Sponsors: 
Aerospace, Bioengineering, Applied Mechanics, Design Engineering Division, Advanced Energy Systems, Manufacturing Engineering Division, Noise Control and Acoustics, Nondestructive Evaluation, Diagnosis, and Prognosis (NDPD), Nuclear Engineering Division, Process Industries Division, Fluids Engineering, Heat Transfer, Materials, Microelectromechanical Systems, Safety Engineering and Risk Analysis, Computers & Information in Engineering


Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2020/volume/84478

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