Finite Element Modeling of the Workpiece Thermal Distortion in MQL Deep-Hole Drilling

2011 ◽  
Author(s):  
Bruce L. Tai ◽  
Steven B. White ◽  
David A. Stephenson ◽  
Albert J. Shih
Keyword(s):  
Heat Flux ◽  
Finite Element ◽  
Finite Element Modeling ◽  
Heat Carrier ◽  
Hole Drilling ◽  
Thermal Distortion ◽  
Deep Hole ◽  
Deep Hole Drilling ◽  
Element Modeling ◽  
Carrier Model

This paper develops a three dimensional (3-D) finite element modeling (FEM) to predict the workpiece thermal distortion in minimum quantity lubrication (MQL) deep-hole drilling. Drilling-induced heat fluxes on the drilled hole bottom surface (HBS) and hole wall surface (HWS) are first determined by the inverse heat transfer method. The proposed 3-D heat carrier model consisting of shell elements to carry the HWS heat flux and solid elements to carry the HBS heat flux conducts the heat to the workpiece to mimic drilling process. A coupled thermal-elastic analysis is used to calculate the workpiece thermal distortion at each time step based on the temperature distribution. The heat carrier model is validated by comparing the temperature profiles at selected points with those from an existing 2-D axisymmetric advection model. The capability for modeling distortion in the case of drilling multiple deep-holes is also demonstrated.

Workpiece Thermal Distortion in Minimum Quantity Lubrication Deep Hole Drilling—Finite Element Modeling and Experimental Validation

2012 ◽  
Vol 134 (1) ◽  
Author(s):  
Bruce L. Tai ◽  
Andrew J. Jessop ◽  
David A. Stephenson ◽  
Albert J. Shih
Keyword(s):  
Heat Flux ◽  
Finite Element ◽  
Heat Carrier ◽  
Three Dimensional ◽  
Minimum Quantity Lubrication ◽  
Hole Drilling ◽  
Bottom Surface ◽  
Thermal Distortion ◽  
Element Analysis ◽  
Minimum Quantity

This paper presents the three dimensional (3-D) finite element analysis (FEA) to predict the workpiece thermal distortion in drilling multiple deep-holes under minimum quantity lubrication (MQL) condition. Heat sources on the drilling hole bottom surface (HBS) and hole wall surface (HWS) are first determined by the inverse heat transfer method. A 3-D heat carrier consisting of shell elements to carry the HWS heat flux and solid elements to carry the HBS heat flux has been developed to conduct the heat to the workpiece during the drilling simulation. A thermal–elastic coupled FEA was applied to calculate the workpiece thermal distortion based on the temperature distribution. The concept of the heat carrier was validated by comparing the temperature calculation with an existing 2-D advection model. The 3-D thermal distortion was validated experimentally on an aluminum workpiece with four deep-holes drilled sequentially. The measured distortion on the reference point was 61 μm, which matches within uncertainty the FEA predicted distortion of 51 μm.

Joule Heating and Peltier Effects in Thermoelectric Spin-Transfer Torque Mram Devices Using Finite Element Modeling

2014 ◽  
Vol 931-932 ◽  
pp. 989-993 ◽  
Author(s):  
Supakorn Harnsoongnoen ◽  
N. Phaengpha ◽  
S. Ritjaroenwattu ◽  
U. Charoen-In ◽  
Apirat Siritaratiwat
Keyword(s):  
Heat Flux ◽  
Finite Element ◽  
Finite Element Modeling ◽  
Joule Heating ◽  
Tunnel Junction ◽  
Magnetic Tunnel Junction ◽  
Spin Transfer Torque ◽  
Spin Transfer ◽  
Maximum Temperature ◽  
Element Modeling

This paper reports the Joule heating and Peltier effects in thermoelectric spin-transfer torque MRAMs (TSTT-MRAMs). The simulation was undertaken based on the current-induced magnetization switching at the MgO/CoFe magnetic tunnel junction. Thermal and heat flux distributions of the TSTT-MRAM cells were simulated and analyzed using finite-element modeling. The Joule heating and Peltier effects lead to the increases in the temperature and heat flux distributions at the magnetic tunnel junction (MTJ) as well as the thermoelectric module. The maximum temperature of Peltier effect is higher than Joule heating effect when voltage amplitude below 0.77V. Some practical data for the STT-MRAM were also reported.

Workpiece Temperature During Deep-Hole Drilling of Cast Iron Using High Air Pressure Minimum Quantity Lubrication

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Bruce L. Tai ◽  
David A. Stephenson ◽  
Albert J. Shih
Keyword(s):  
Heat Flux ◽  
Cast Iron ◽  
Heat Generation ◽  
Minimum Quantity Lubrication ◽  
Air Pressure ◽  
Hole Drilling ◽  
Deep Hole ◽  
Deep Hole Drilling ◽  
Workpiece Temperature ◽  
Minimum Quantity

This research investigates heat generation and workpiece temperature during deep-hole drilling of cast iron under a high air pressure minimum quantity lubrication (MQL). The hole wall surface (HWS) heat flux, due to drill margin friction and high temperature chips, is of particular interest in deep-hole drilling since it potentially increases the workpiece thermal distortion. This study advances a prior drilling model to quantify the effect of higher air pressure on MQL drilling of cast iron, which is currently performed via flood cooling. Experiments and numerical analysis for drilling holes 200 mm in depth on nodular cast iron work material with a 10 mm diameter drill were conducted. Results showed that the low drill penetration rate can cause intermittent chip clogging, resulting in tremendous heat; however this phenomenon could be eliminated through high air pressure or high feed and speed. Conversely, if the drilling process is stable without chip clogging and accumulation, added high air pressure is found to have no effect on heat generation. The heat flux though the HWS contributes over 66% of the total workpiece temperature rise when intermittent chip clogging occurs, and around 20% to 30% under stable drilling conditions regardless of the air pressure. This paper demonstrated the significance of HWS heat flux and the potential of high air pressure used in conjunction with MQL technology.

High Air Pressure in MQL Deep Hole Drilling Workpiece Temperature

2011 ◽  
Vol 189-193 ◽  
pp. 1732-1736 ◽  
Author(s):  
Bruce L. Tai ◽  
David Stephenson ◽  
Steven White ◽  
Albert Shih
Keyword(s):  
Heat Flux ◽  
Minimum Quantity Lubrication ◽  
High Heat ◽  
Heat Fluxes ◽  
Air Pressure ◽  
Hole Drilling ◽  
High Heat Flux ◽  
Deep Hole ◽  
Deep Hole Drilling ◽  
Workpiece Temperature

This study investigates the effect of air pressure on workpiece temperature in through tool minimum quantity lubrication (MQL) deep-hole drilling. Experiments on 200 mm deep holes drilled by a 10 mm carbide drill were conducted under regular (500 kPa) and high (1000 kPa) air pressure conditions. Torque data shows that the chip clogging problem occurring under regular air pressure can be solved by the high air pressure. An inverse heat transfer method is utilized to quantify the heat fluxes and calculate the temperature distribution during drilling based on embedded thermocouples along the depth. Results show that temperature around the hole increases rapidly when the chips start accumulating in the hole under regular air pressure and cause high heat flux on the drilled hole wall surface. The high pressure condition, prevents chip accumulation, thus reducing the total heat flux.

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