MORPHOLOGICAL ANALYSIS OF CUTTING TOOL DESIGNS WITH COOLING BY MEANS OF HEAT PIPES

2020 ◽  
Author(s):  
A.S. Zhuravlev ◽  
Keyword(s):  
Morphological Analysis ◽  
Cutting Tool ◽  
Heat Pipes

An Investigation on Cutting Tool Temperatures in Composite Machining Assisted With Heat-Pipe Cooling

2005 ◽  
Author(s):  
Jie Liu ◽  
Y. Kevin Chou ◽  
Mark T. North ◽  
Kirk A. Bennett
Keyword(s):  
Heat Flux ◽  
Partition Coefficient ◽  
Heat Pipe ◽  
Heat Dissipation ◽  
Cutting Tool ◽  
Heat Pipes ◽  
Rake Face ◽  
Heat Partition ◽  
Coated Tools ◽  
Coating Failure

Metal matrix composites (MMC) are difficult to cut materials, and yet only diamond tools have been successfully utilized for such machining applications. Wear of diamond-coated tools is characterized by catastrophic coating failure (peeling off) due to the adhered work materials at the flank wear-land surface and the high stress developed at the coating-substrate interface, associated with high temperatures, because of very different thermal expansion coefficients. Temperature reductions, therefore, may delay the onset of the coating failure and offer tool life extension. A passive heat-dissipation device, heat-pipe, has been tested for cutting temperature reductions in MMC machining. Though it is intuitive that heat pipes may enhance heat transfer and plausibly reduce the tool temperatures, heat pipes may also increase heat partitioning into the tool, and complicate its effects on the heat removal and temperature reduction efficiency. This paper reports aluminum composite machining by diamond-coated tools and investigates the heat-pipe effects on tool temperature reductions. Numerical simulation of heat conduction in the cutting tool system was performed to evaluate cutting tool temperatures without and with a heat-pipe. A 3-D thermal model of the cutting tool system including coating, insert substrate, and tool holder was established. The heat source was characterized as a heat flux, a portion of the frictional heat flux at the rake face, over the chip-tool contact area. To determine the heat-partition coefficient, a separate 2-D chip model was established with a heat flux, balanced the total rake-face heat flux, over the contact and moving with the chip speed. With the tool and chip thermal models and by matching the average temperature at the tool-chip contact of the two models, the heat partition coefficient can be numerically determined. The model has been used to evaluate how the heat-pipe modifies the cutting tool temperatures. Applying heat-pipe cooling inevitably increases the heat partition into the tool despite the enhanced heat dissipation. However, the heat pipe still effectively reduces the tool-chip contact temperatures, depending upon machining conditions. Cutting tool temperatures have also been measured in machining using thermocouples. The simulation results reasonably agree with the experimental measurements.

Prediction of Heat Transfer Behavior of Carbide Inserts With Embedded Heat Pipes for Dry Machining

2002 ◽  
Author(s):  
Richard Y. Chiou ◽  
Jim S. J. Chen ◽  
Lin Lu ◽  
Ian Cole
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Temperature Distribution ◽  
Tool Wear ◽  
Heat Pipe ◽  
Cutting Tool ◽  
Heat Pipes ◽  
Clear Understanding ◽  
Dry Machining ◽  
Element Analysis

The temperature of a tool plays an important role in thermal distortion and the machined part’s dimensional accuracy, as well as in tool life in machining. The most significant factors in tool wear are temperature and the degree of chemical affinity between the tool and the workpiece. This research focuses on developing a clear understanding of the temperature distribution with cutting tool inserts embedded with heat pipes to eliminate the use of cutting fluids and reduce tool wealr in machining. A novel approach using the finite element analysis was developed to simulate the thermal behavior of a carbide cutting tool in three-dimensional dry machining. The carbide tools possess high material strengths at room temperature, but they cannot retain useful hardness at temperatures above 900°C (1700°F). Therefore, the reduction of tool wear typically requires maintaining the temperature of cutting tool inserts below some critical values. The particular temperature distribution depends on density, specific heat, thermal conductivity, shape and contact of the tool and heat pipe. Finite Element Analysis (FEA) shows that the temperature drops greatly at the tool-chip interface and that the heat flow to the tool is effectively removed when a heat pipe is embedded.

The Chatterbox: A Device for Hearing Chatter as Sections are Cut

1973 ◽  
Vol 31 ◽  
pp. 360-361
Author(s):  
C. W. McCutchen ◽  
Lois W. Tice
Keyword(s):  
Machine Tools ◽  
Cutting Tool ◽  
Guerilla Warfare ◽  
History Of ◽  
Chatter Marks

Ultramicrotomists live in a state of guerilla warfare with chatter. This situation is likely to be permanent. We can infer this from the history of machine tools. If set the wrong way for the particular combination of cutting tool and material, most if not all machine tools will chatter.In more than 100 years since machine tools became common, no one has evolved a practical recipe that guarantees avoiding chatter. Rather than follow some single very conservative rule to avoid chatter in all cases, machinists detect it when it happens, and change conditions until it stops. This is possible because they have no trouble telling when their cutting tool is chattering. They can see chatter marks, and they can also hear a sometimes deafening noise.

Structural and Chemical Studies of Pathological Fibers in Human Neurofibrillary Degeneration

1985 ◽  
Vol 43 ◽  
pp. 726-729
Author(s):  
K.S. Kosik ◽  
L.K. Duffy ◽  
S. Bakalis ◽  
C. Abraham ◽  
D.J. Selkoe
Keyword(s):  
Monoclonal Antibodies ◽  
Alzheimer Disease ◽  
Human Brain ◽  
Neurofibrillary Tangles ◽  
Morphological Analysis ◽  
High Specificity ◽  
Cytoskeletal Proteins ◽  
Neuritic Plaque ◽  
Protein Chemistry ◽  
Chemical Studies

The major structural lesions of the human brain during aging and in Alzheimer disease (AD) are the neurofibrillary tangles (NFT) and the senile (neuritic) plaque. Although these fibrous alterations have been recognized by light microscopists for almost a century, detailed biochemical and morphological analysis of the lesions has been undertaken only recently. Because the intraneuronal deposits in the NFT and the plaque neurites and the extraneuronal amyloid cores of the plaques have a filamentous ultrastructure, the neuronal cytoskeleton has played a prominent role in most pathogenetic hypotheses.The approach of our laboratory toward elucidating the origin of plaques and tangles in AD has been two-fold: the use of analytical protein chemistry to purify and then characterize the pathological fibers comprising the tangles and plaques, and the use of certain monoclonal antibodies to neuronal cytoskeletal proteins that, despite high specificity, cross-react with NFT and thus implicate epitopes of these proteins as constituents of the tangles.

Dynamics of the processes in metal machining

1998 ◽  
Vol 2 ◽  
pp. 115-122
Author(s):  
Donatas Švitra ◽  
Jolanta Janutėnienė
Keyword(s):  
High Frequency ◽  
Machine Tools ◽  
Metal Cutting ◽  
Cutting Tool ◽  
Low Frequency ◽  
Metal Cutting Machine ◽  
Cutting Machine ◽  
Metal Machining

In the practice of processing of metals by cutting it is necessary to overcome the vibration of the cutting tool, the processed detail and units of the machine tool. These vibrations in many cases are an obstacle to increase the productivity and quality of treatment of details on metal-cutting machine tools. Vibration at cutting of metals is a very diverse phenomenon due to both it’s nature and the form of oscillatory motion. The most general classification of vibrations at cutting is a division them into forced vibration and autovibrations. The most difficult to remove and poorly investigated are the autovibrations, i.e. vibrations arising at the absence of external periodic forces. The autovibrations, stipulated by the process of cutting on metalcutting machine are of two types: the low-frequency autovibrations and high-frequency autovibrations. When the low-frequency autovibration there appear, the cutting process ought to be terminated and the cause of the vibrations eliminated. Otherwise, there is a danger of a break of both machine and tool. In the case of high-frequency vibration the machine operates apparently quiently, but the processed surface feature small-sized roughness. The frequency of autovibrations can reach 5000 Hz and more.

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