Finish Cutting of Carbide Mold with Thermally Affected Layer by Diamond Tool

2012 ◽  
Vol 565 ◽  
pp. 382-387
Author(s):  
Kazuki Imazato ◽  
Koichi Okuda ◽  
Hiroo Shizuka ◽  
Masayuki Nunobiki
Keyword(s):  
Surface Roughness ◽  
Tool Wear ◽  
Cutting Force ◽  
Diamond Tool ◽  
Depth Of Cut ◽  
Good Surface ◽  
Finish Cutting ◽  
Ultra Precision ◽  
Cutting Experiments ◽  
Edm Process

This paper deals with finish cutting of thermally affected layer on cemented carbide by a diamond tool in order to machine efficiently the carbide mold with high accuracy and good surface without a polishing. The microstructure of thermally affected layer left by EDM process was observed and analyzed by EPMA. Its hardness and thickness were measured. Subsequently, the cutting experiments were carried out by using a PCD tool and an ultra-precision cutting machine. The effects of the thermally affected layer on the surface roughness, the cutting force and the tool wear were investigated. As a result, it was confirmed that the cutting force decreased with an increase in the depth of cut. Furthermore, it was found that the tool wear and the surface roughness obtained by cutting the thermally affected layer were greater than those of the original workpiece.

Cutting Force Evolution and its Power Spectrum Analysis with Tool Wear Progress in Ultra-Precision Raster Milling

2014 ◽  
Vol 625 ◽  
pp. 20-25
Author(s):  
Guo Qing Zhang ◽  
Suet To ◽  
Gao Bo Xiao
Keyword(s):  
Power Spectrum ◽  
Tool Wear ◽  
Cutting Force ◽  
Spectrum Analysis ◽  
Diamond Tool ◽  
Power Spectrum Analysis ◽  
Spectrum Density ◽  
Ultra Precision ◽  
The Time Domain ◽  
Cutting Experiments

In this paper, cutting force and its power spectrum analysis at different tool wear levels are explored. A dynamic model is established to simulate the measured cutting force compositions, and a series of cutting experiments have been conducted to investigate the cutting force evolution with the tool wear progress. Research results reveal that in the time domain, the cutting force in UPRM is characterized as a force pulse follows by a damped vibration signals, the vibration can be modeled by a second order impulse response of the measurement system. While in the frequency domain, it is found that the power spectrum density at the natural frequency of dynamometer increases with the progress of tool wear, which therefore can be utilized to monitor diamond tool wear in UPRM.

An Experimental Study on Finish Dry Milling of AISI 321 Stainless Steel

2016 ◽  
Vol 861 ◽  
pp. 26-31 ◽  
Author(s):  
Peng Guo ◽  
Chuan Zhen Huang ◽  
Bin Zou ◽  
Jun Wang ◽  
Han Lian Liu ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Stainless Steel ◽  
Tool Wear ◽  
Cutting Force ◽  
Feed Rate ◽  
Cutting Speed ◽  
Depth Of Cut ◽  
Dry Milling ◽  
Aisi 321 ◽  
Coated Cemented Carbide

The milling of AISI 321 stainless steel which has wide engineering applications particularly in automobile, aerospace and medicine is of great importance especially in the conditions where high surface quality is required. In this paper, L16 orthogonal array design of experiments was adopted to evaluate the machinability of AISI 321 stainless steel with coated cemented carbide tools under finish dry milling conditions, and the influence of cutting speed ( V ), feed rate ( f ) and depth of cut ( ap ) on cutting force, surface roughness and tool wear was analysed. The experimental results revealed that the cutting force decreased with an increase in the cutting speed and increased with an increase in the feed rate or the depth of cut. The tool wear was affected significantly by the cutting speed and the depth of cut, while the effect of the feed rate on the tool wear was insignificant. With the cutting speed increased up to 160 m/min, a decreasing tendency in the surface roughness was observed, but when the cutting speed was further increased, the surface roughness increased. The effect of the feed rate and the depth of cut on the surface roughness was slight.

Experimental Investigation of the Tool Wear and Tool Life in Micro Hard Milling

2013 ◽  
Author(s):  
Shreyas Shashidhara ◽  
Xinyu Liu ◽  
Weihang Zhu ◽  
James Curry ◽  
Victor Zaloom
Keyword(s):  
Surface Roughness ◽  
Tool Wear ◽  
Abrasive Wear ◽  
Cutting Force ◽  
Tool Life ◽  
Micro Milling ◽  
Depth Of Cut ◽  
Dry Machining ◽  
Edge Chipping ◽  
Edge Radius

The objective of this project is to experimentally investigate the influence of Minimum Quantity Lubrication (MQL) on tool wear and tool life in micro hardmilling. The experiments were performed on stainless steel using uncoated WC micro-mill with the nominal diameter of 508 microns. The tool wear is characterized by the volume of the material loss at the tool tip. In order to reveal the progression of the tool wear, the worn tool was examined periodically under SEM after a fixed amount of workpiece material removal (1.25 mm3 or 5 slots in this study). The tool life was characterized as the amount of material removed, instead of the conventional cutting times. The feedrate and the spindle speed were fixed, and two levels of axial depth of cut (50 and 75 microns) were compared. The higher depth of cut leads to longer tool life. The machining performance under MQL is superior to the dry machining for both process conditions in terms of the tool life. The cutting forces in feed direction and the surface roughness at the bottom of the slots were also examined during the experiments. The magnitude of the machining forces showed cyclic pattern for both MQL and dry machining. The SEM images and the cutting force signals suggested that the dominant mode of the tool wear in micro-milling is edge chipping and abrasive wear at the tool tip. The loss of the micro-grain of WC at the cutting edge leads to edge chipping, which reduces the effective cutting diameter; the abrasive wear enlarge the edge radius, causing the cutting force increase. As the cutting edge radius reaches a certain dimension, the whole edge was stripped off, a new edge formed with a smaller edge radius, and the cycle restarts. Under MQL cutting conditions, three cycles were observed before tool failure, while under dry machining conditions, the tool only experienced two cycles before tool breakage. The surface roughness at the bottom of the slots improved significantly with the application of MQL for all levels of the tool wear. The surface roughness did not increase drastically as the tool wear increased. It reached a plateau after the tool wear went into gradual wear state. Further experiments and theoretical analysis will be pursued in the future to gain a deeper understanding of tool wear mechanism in micro-milling.

Chip Formation in Ultra-Precision Machining of Nitrocarburized Steels

2012 ◽  
Vol 516 ◽  
pp. 293-298 ◽  
Author(s):  
Jen Osmer ◽  
Ralf Gläbe ◽  
Ekkard Brinksmeier
Keyword(s):  
Surface Roughness ◽  
Tool Wear ◽  
Chip Formation ◽  
Diamond Tool ◽  
Compound Layer ◽  
Surface Generation ◽  
Precision Machining ◽  
Surface Compound ◽  
Steel Alloys ◽  
Ultra Precision

For the replication of optical glass or plastic components moulding inserts with surface roughness in the nanometre range and form accuracy in the micron or sub-micron range are needed. Despite these requirements the applied moulding insert material has to suit further needs like high temperature stability and resistivity against abrasive and chemical wear. To satisfy the specific requirements of replication processes steel alloys can be heat treated in a way to meet these demands. Unfortunately, these steel alloys cannot be machined with single crystal diamond tools because catastrophic diamond tool wear occurs. In recent years good progress in the field of ultra precision machining of steel has been made by nitrocarburizing the steel alloy. This leads to a sub-surface compound layer which is diamond machinable with surface roughness Sa < 10 nm and reduced diamond tool wear. But the ultra precision machining of these nitrocarburized steels introduces new challenges caused by the high hardness of the compound layer. Typical values are about 1200HV0.025. Therefore, this paper presents results from ultra precision machining processes focusing on the material behaviour during the cutting process. Influences of depth of cut and material composition on the surface generation can be found by evaluating chip formation and the resulting chips. Furthermore, the sub-surface of ultra precision machined steels is characterized by metallographic analysis to evaluate the influence of the nitrocarburizing process on ultra precision machining. In conclusion this paper presents the results for a deeper understanding of the material removal mechanisms in ultra precision machining of nitrocarburized steels.

Diamond Tool Wear in the Ultra-Precision Cutting of Large Electroless Nickel Coated Molding Dies

2011 ◽  
Vol 5 (3) ◽  
pp. 283-288 ◽  
Author(s):  
Akira Shinozaki ◽  
◽  
Yoshiharu Namba
Keyword(s):  
Surface Roughness ◽  
Tool Wear ◽  
Diamond Tool ◽  
Thin Foil ◽  
Electroless Nickel ◽  
Observation System ◽  
Shape Error ◽  
Shape Accuracy ◽  
Small Surface ◽  
Ultra Precision

In recent years, in a field of space science, large and high precision aspherical molding dies which are used to make aspherical thin foil mirrors for the hard Xray telescope are needed. Therefore to establish the ultra-precision cutting method for these dies is overly expected. In the actual manufacturing, the largemolding die is required to have both high accurate shape accuracy and very small surface roughness as the finished product. To machine the large molding die which has these high accuracies, we should know factors to cause various errors such as shape error and surface roughness and so on. Because it is necessary to machine the large molding die by using NC machining system that automatically corrects shape error finally. Especially, the tool wear of diamond tool is one of the big factors that influences shape error and surface roughness, so it needs to correct the amount of tool wear while ultra-precision cutting of large molding dies. From these points of view, in this research, a tool wear of diamond tool which is used in the ultra-precision cutting of large electroless nickel coated molding dies is considered with an on-machine measurement and observation system.

The Study of the Influence of Tool Wear on Cutting Temperature in Diamond Ultra-Precision Cutting of Aluminum Alloy Mirror

2016 ◽  
Vol 693 ◽  
pp. 982-989 ◽  
Author(s):  
Yuan Jing Zhang ◽  
Guo Jun Dong ◽  
Ming Zhou
Keyword(s):  
Aluminum Alloy ◽  
Tool Wear ◽  
Diamond Tool ◽  
Cutting Temperature ◽  
Fem Simulation ◽  
Thermal Imager ◽  
Average Width ◽  
Ultra Precision ◽  
Flank Face ◽  
Cutting Experiments

This paper performed a series of finite element method (FEM) simulation to investigate the influence of the tool wear on the cutting temperature in the diamond ultra-precision cutting of the aluminum alloy mirror. The two-dimensional FEM model including the diamond tool with the different average width of wear land on flank face was established. A series of ultra-precision cutting experiments using different cutting distance was performed. The tool wear was detected by scanning electron microscopy (SEM), and the cutting temperature was detected by infrared thermal imager. The comparison of the simulation investigations and the experimental investigations was done. The results revealed that the cutting temperature increases with an increase of the average width of wear land on flank face in the FEM simulation. And in the ultra-precision cutting experiments the diamond tool wear becomes severe as the cutting distance increases, meanwhile the severe tool wear results in the higher cutting temperature. Consequently the FEM simulations prove to be right.

Force Based Model for Automated Surface Roughness Prediction in Slot Milling

2001 ◽  
Author(s):  
A. Sarhan ◽  
A. A. Nasr ◽  
R. M. El-Zahry
Keyword(s):  
Surface Roughness ◽  
Tool Wear ◽  
Cutting Force ◽  
Control Surface ◽  
Percentage Error ◽  
Depth Of Cut ◽  
Monitoring And Control ◽  
Slot Milling ◽  
On Line ◽  
And Control

Abstract Study was carried out to analyze the dynamic cutting signals of slot-milling process, in order to design automated on-line tool and surface roughness monitoring strategies, based on indices extracted from these signals, to automatically monitor and control surface roughness in slot milling. Especially designed and manufactured sensitive strain gage dynamometer was used to measure slot-milling radial and tangential forces during milling cycle. The dynamometer was calibrated in static and dynamic ranges. The effect of flank wear width on the magnitude of the cutting force harmonics was constructed as function of axial depth of cut, feed rate per tooth, specific cutting pressure of work material and instantaneous angle of rotation. The results were plotted at various cutting conditions in time and frequency domains. The tool wear was measured in an off-line manner using the tool maker’s microscope and interrelationships of cutting force harmonics and tool wear magnitude were constructed and were used in the computer simulation. Surface roughness was measured using surface meter (Surtronic 3+) with a portable printer. The cutting force signal harmonics were used to establish the proposed force based model to predict the surface roughness of the workpiece machined in slot-milling and examining this system by another experimental tests to define the reliability of the system and to define the percentage error of the system model. Hence, an index named as surface index (S.I) is extracted from ratio between first force amplitude at first significant frequency and first surface amplitude at the same frequency, to predict the surface roughness of the workpiece machined in slot-milling. This is to be employed in automated on-line quality management (monitoring and control) strategy.

Study on Surface Finish of Carbon Steel by Ultra-Precision Diamond Cutting

2014 ◽  
Vol 1017 ◽  
pp. 367-372
Author(s):  
Yoshiki Kamoi ◽  
Koichi Okuda ◽  
Hiroo Shizuka ◽  
Masayuki Nunobiki
Keyword(s):  
Surface Roughness ◽  
Carbon Steel ◽  
Tool Wear ◽  
Carbon Content ◽  
Surface Finish ◽  
Diamond Tool ◽  
Diamond Cutting ◽  
Finished Surface ◽  
Ultra Precision

This paper describes an influence of the cutting atmosphere and the carbon content on the surface roughness and tool wear in CO2-blow cutting of carbon steel with a diamond tool. The cutting tests were carried out by changing the cutting atmosphere and carbon contains in order to investigate the effect on the improvement of surface finish and the reduction of tool wear. The results indicated that the roughness on finished surface was improved by cutting in CO2 gas blow atmosphere and the tool wear increased with a decrease in the carbon content.

The Cutting Behavior of Diamond Coated Tool in Machining Al-20wt%Si Alloy

2010 ◽  
Vol 431-432 ◽  
pp. 365-368
Author(s):  
Wen Zhuang Lu ◽  
Dun Wen Zuo ◽  
B. Yang ◽  
Feng Xu ◽  
M. Wang
Keyword(s):  
Surface Roughness ◽  
Tool Wear ◽  
Cutting Force ◽  
Feed Rate ◽  
Cutting Tool ◽  
Cvd Diamond ◽  
Cemented Carbide ◽  
Depth Of Cut ◽  
Coated Tool ◽  
Coated Cemented Carbide

The performance of CVD diamond coated cemented carbide cutting tool in comparison with K10 uncoated cemented carbide tool in the dry turning of Al-20wt%Si aluminum-silicon hypereutectic alloy was investigated. The obtained results showed a better cutting performance for CVD diamond coated tool in machining Al-20wt%Si, particularly in terms of cutting force, tool wear, surface roughness, when compared with K10. The cutting forces are lower with CVD diamond coated tool and the depth of cut promotes a great increment of the cutting force. The tool wear processes taking place in the tool tips in all cutting conditions. The tool life of CVD diamond coated tool is longer than that of the uncoated K10. The surface roughness Ra increases obviously with the increase of feed rate using a CVD diamond coated cutting tool. A higher feed rate produces surface rougher. The chip morphology in machining of Al-20wt%Si alloy by CVD diamond coated tool is continuous. The tests showed that the CVD diamond coated tool can be applied on the K10 tool at low feed rate to produce high quality surfaces.

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