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

2019 ◽  
Vol 109 (01-02) ◽  
pp. 30-34
Author(s):  
D. Müller ◽  
B. Kirsch ◽  
J. C. Aurich
Keyword(s):  
Numerical Simulations ◽  
Cemented Carbide ◽  
Drilling Process ◽  
Cooling Channel ◽  
Channel Diameter ◽  
Channel Outlet ◽  
Internally Cooled ◽  
Cooling Lubricant ◽  
Cemented Carbide Drills

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.

scholarly journals Internal face finishing for a cooling channel using a fluid containing free abrasive grains

2021 ◽  
Author(s):  
Mitsugu Yamaguchi ◽  
Tatsuaki Furumoto ◽  
Shuuji Inagaki ◽  
Masao Tsuji ◽  
Yoshiki Ochiai ◽  
...  
Keyword(s):  
High Speed ◽  
Flow Behavior ◽  
Flow Simulation ◽  
Cooling Channel ◽  
H13 Steel ◽  
Channel Diameter ◽  
Abrasive Grains ◽  
Low Viscosity ◽  
Short Period ◽  
Internal Pressures

AbstractIn die-casting and injection molding, a conformal cooling channel is applied inside the dies and molds to reduce the cycle time. When the internal face of the channel is rough, both cooling performance and tool life are negatively affected. Many methods for finishing the internal face of such channels have been proposed. However, the effects of the channel diameter on the flow of a low-viscosity finishing media and its finishing characteristics for H13 steel have not yet been reported in the literature. This study addresses these deficiencies through the following: the fluid flow in a channel was computationally simulated; the flow behavior of abrasive grains was observed using a high-speed camera; and the internal face of the channel was finished using the flow of a fluid containing abrasive grains. The flow velocity of the fluid with the abrasive grains increases as the channel diameter decreases, and the velocity gradient is low throughout the channel. This enables reduction in the surface roughness for a short period and ensures uniform finishing in the central region of the channel; however, over polishing occurs owing to the centrifugal force generated in the entrance region, which causes the form accuracy of the channel to partially deteriorate. The outcomes of this study demonstrate that the observational finding for the finishing process is consistent with the flow simulation results. The flow simulation can be instrumental in designing channel diameters and internal pressures to ensure efficient and uniform finishing for such channels.

scholarly journals Monitoring of drilling conditions using the Hilbert-Huang transformation

2018 ◽  
Vol 148 ◽  
pp. 16003 ◽  
Author(s):  
Piotr Wolszczak ◽  
Grzegorz Litak ◽  
Marek Dziuba
Keyword(s):  
Fourier Transform ◽  
Numerical Simulations ◽  
Hilbert Transform ◽  
Geometrical Parameters ◽  
Drilling Process ◽  
Nonlinear Characteristics ◽  
Different Types ◽  
Fourier Spectra ◽  
Backbone Curves ◽  
Drilling Conditions

The article presents the results of design and monitoring the drilling process. Vibroacoustic sensors were used to observe spindle vibrations. These signals were subjected to a Huang decomposition and a Fourier transform. Results for various conditions were studied and classified with help of Fourier spectra and the envelope curves. Using the additional results of numerical simulations sources of vibration were identified. We considered four different types of drilling which were diversified in terms of geometrical parameters of blades. The application of Hilbert transform enable to find nonlinear characteristics via the deflection profile of resonance backbone curves.

Determining the Tool Life of a Cemented Carbide Drill Using Optimized Process, Delivery System, and Drill Design Parameters in Deep Hole Drilling Using Environment Friendly Machining Method

2010 ◽  
Author(s):  
Muhammad I. Hussain ◽  
A. Filipovic ◽  
J. Dasch ◽  
D. Simon
Keyword(s):  
Tool Life ◽  
Metal Removal ◽  
Cemented Carbide ◽  
Design Parameters ◽  
Innovative Technology ◽  
Hole Drilling ◽  
Deep Hole ◽  
Deep Hole Drilling ◽  
High Production ◽  
Cemented Carbide Drills

Near dry machining or Minimum Quantity Lubrication (MQL) methodology appears to be a valid solution to meet environmental challenges of metal removal processes. However, in order to implement environmentally friendly machining into high production manufacturing environments, it is imperative to invent a robust solution for a wide variety of machined features. In previous work by the authors, capabilities of the MQL process, calibrated for machining extremely deep holes with length to diameter (L/D) ratio of up to 15, were proven. An optimal machining solution was developed using the Box and Behnken experimental design approach, and it was demonstrated that cemented carbide drills with proper cutting geometry and MQL settings can be used for deep hole drilling of aluminum. This work, focused on developing a production ready application, proved that MQL technology is also robust enough to achieve adequate tool life for high volume manufacturing requirements. It actually exhibited that such approach may even exceed tool life requirements currently enforced for conventional processes using gun drills or G-drills. In addition, machining time was significantly reduced with this innovative technology achieving productivity approximately 7 times higher than in traditional drilling operations. Considering these achievements, MQL has been demonstrated to be the drilling technology of future that will help reducing capital investments into production machinery and minimize landfill discharges of high production manufacturing facilities.

PERFORMANCE OF COATED CEMENTED CARBIDE DRILLS IN DRILLING OF GRAY CAST IRON UNDER DIFFERENT LUBRI-COOLING CONDITIONS

2017 ◽  
Author(s):  
Eder Silva Costa ◽  
Pedro Henrique Pires França ◽  
CARLA RAMOS ◽  
Wisley Sales ◽  
Álisson Rocha Machado ◽  
...  
Keyword(s):  
Cast Iron ◽  
Gray Cast Iron ◽  
Cemented Carbide ◽  
Gray Cast ◽  
Cooling Conditions ◽  
Cemented Carbide Drills ◽  
Coated Cemented Carbide

Effect of Entrance Geometry and Rotation on Heat Transfer in a Narrow (AR = 1:4) Rectangular Internal Cooling Channel

2014 ◽  
Author(s):  
Krishnendu Saha ◽  
Sumanta Acharya
Keyword(s):  
Heat Transfer ◽  
Aspect Ratio ◽  
Numerical Simulations ◽  
Flow Distribution ◽  
Leading Edge ◽  
Secondary Flows ◽  
Internal Cooling ◽  
Cooling Channel ◽  
Cross Sectional ◽  
Density Ratios

This paper studies the effect of entrance geometries on the heat transfer and fluid flow in a narrow aspect ratio (AR = 1:4) rectangular internal cooling channel, representative of a leading edge of a gas turbine blade, under rotating condition. Numerical simulations are performed to understand the role of the rotation generated forces on the flow for different entrance geometries representative of those encountered in practice. Three different entrance geometries are tested: a S-shape entrance, a 90 degree bend entrance and a twisted entrance that changes its aspect ratio along its length. Numerical simulations are run at a constant Reynolds number (Re = 15000), for a range of rotation numbers (Ro = 0–0.2) and density ratios (DR = 0–0.4). Detailed heat transfer coefficient data at the leading and trailing walls are presented along with streamline profiles at different cross sectional planes that provide an insight into the flow field. It is seen that the entrance profile upstream of the actual test section is significantly different for the different entrance geometries, and has a significant impact on the rotation generated secondary flows. Non-uniformity in flow distribution at the exit of entrance geometry is small for the S-shape entrance while the non-uniformity is prominent at the exit of the changing AR entrance geometry. The entrance effect dies down as the flow progresses further downstream inside the cooling channel and the rotation effect becomes dominant.

Drilling of CFRP/Ti6Al4V Stack Board

2013 ◽  
Vol 7 (4) ◽  
pp. 426-432 ◽  
Author(s):  
Junsuke Fujiwara ◽  
◽  
Ryuichi Nagaura ◽  
Tetsuya Tashiro ◽  
Keyword(s):  
Tool Life ◽  
Water Mist ◽  
Cemented Carbide ◽  
Cooling Process ◽  
Dry Cutting ◽  
Dry Process ◽  
Drill Cutting ◽  
Mist Cooling ◽  
Cemented Carbide Drills ◽  
Coated Cemented Carbide

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.

Numerical Study on Local Heat Transfer in a Rotating Cooling Channel

2018 ◽  
Author(s):  
Min Ren ◽  
Xueying Li ◽  
Jing Ren ◽  
Hongde Jiang
Keyword(s):  
Heat Transfer ◽  
Rotation Number ◽  
Numerical Study ◽  
Density Ratio ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Hydraulic Diameter ◽  
Internal Cooling ◽  
Cooling Channel ◽  
Channel Diameter

Effect of rotation on turbine blade internal cooling is an important factor in gas turbine cooling systems. To obtain the distribution of the heat transfer and the flow field in a rotating cooling channel, a series of computational simulations using the realizable k-ε model are utilized. The channel Reynolds number based on the channel diameter is 25000. The rotation number ranges from 0 to 0.20. The investigated density ratio Δρ/ρ ranges from 0.05 to 0.33 and the range of radius-to-passage hydraulic diameter r/D is from 10 to 40. The results show that the heat transfer on the trailing side shows an overall augmentation while that on the leading side decreases in the cooling channel. When the channel is stationary, the density ratio has little effect on the thermal performance. And for the rotating channel, the heat transfer on the trailing side and leading side both increases when the density ratio increases. The heat transfer both on the trailing side and leading side decreases when the radius-to-passage hydraulic diameter (r/D) increase. And the radius has a greater effect when the rotation number is higher.

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