Radial Throw in Micromilling: A Simulation-Based Study to Analyze the Effects on Surface Quality and Uncut Chip Thickness

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Sudhanshu Nahata ◽  
Recep Onler ◽  
O. Burak Ozdoganlar
Keyword(s):  
Surface Roughness ◽  
High Speed ◽  
Accurate Determination ◽  
Chip Thickness ◽  
Quality Metrics ◽  
Uncut Chip Thickness ◽  
Total Displacement ◽  
Simulation Based ◽  
Thickness Variations ◽  
Sidewall Surface

This paper presents a simulation study toward analyzing the effect of radial throw in micromilling on quality metrics and on the deviation in tool-tip trajectory from its prescribed pattern. Both the surface location error (SLE) and the sidewall (peripheral) surface roughness are analyzed. The deviation in tool-tip trajectory is evaluated considering the flute-to-flute variations in the uncut chip thickness and changes in the tooth spacing angle. Radial throw indicates the instantaneous radial location of the tool axis, thereby capturing all salient features of tool-tip trajectory deviations, such as the general elliptical form of the radial motions. This is in contrast to the concept of run-out, which is a scalar quantity (total indicator reading) indicating the total displacement or change in the radial throw measured from a perfect cylindrical surface for one complete rotation of the axis. As such, measurement and analysis of radial throw is essential to understanding micromachining processes. In our previous work, we described an experimental approach for accurate determination of radial throw when using ultra-high-speed micromachining spindles. In this work, we present a simulation-based study to relate radial throw parameters and form to SLE, sidewall surface roughness, flute-to-flute variations of uncut chip thickness, and changes in tooth spacing angle for a two fluted micro-endmill. As expected, our study concludes that the magnitude, orientation, and form of radial throw all significantly affect the studied quality metrics, tooth spacing angle, and the flute-to-flute chip thickness variations. Specifically, the presence of radial throw with an elliptical form induces up to 50% variation in SLE, up to 20% variation in sidewall surface roughness, up to 60% variation in tooth spacing angle deviations, and up to 50% variation in flute-to-flute chip thickness. As such, the presented simulation approach can be used to assess the direct (kinematic) effects of the radial throw parameters on the quality metrics and chip thickness variations.

Investigation on Mechanism of Ultra-Smoothed Surface with a Micro Slot on the Flank Face in Micro Cutting

2014 ◽  
Vol 651-653 ◽  
pp. 764-767
Author(s):  
Tao Zhang ◽  
Hou Jun Qi ◽  
Gen Li
Keyword(s):  
Surface Roughness ◽  
Chip Thickness ◽  
Cutting Edge ◽  
Back Side ◽  
Uncut Chip Thickness ◽  
Micro Cutting ◽  
Cutting Edge Radius ◽  
Edge Radius ◽  
Flank Face ◽  
Side Flow

Micro cutting is a promising manufacturing method to obtain good surface integrity. Surface roughness shows size effect when the uncut chip thickness is smaller than the cutting edge radius. A special micro slot on the flank face of cutting tools was manufactured with discharge. Two groups of micro orthogonal cutting were conducted. The surface roughness of machined surface was measured and compared to each other. The results show that surface roughness decreases first and then increases with the ratio of uncut chip thickness to cutting edge radius. The surface machined with micro slot is better than that of without micro slot due to the micro slot restrain the back side flow of work piece based on the finite element model.

Size Effects in Cutting With a Diamond-Coated Tool

2011 ◽  
Author(s):  
Feng Qin ◽  
Xibing Gong ◽  
Kevin Chou
Keyword(s):  
Residual Stresses ◽  
Size Effect ◽  
Normal Stress ◽  
High Speed ◽  
Chip Thickness ◽  
Tool Geometry ◽  
Uncut Chip Thickness ◽  
Edge Radius ◽  
Coated Tool ◽  
Tool Stresses

In machining using a diamond-coated tool, the tool geometry and process parameters have compound effects on the thermal and mechanical states in the tools. For example, decreasing the edge radius tends to increase deposition-induced residual stresses at the tool edge interface. Moreover, changing the uncut chip thickness to a small-value range, comparable or smaller than the edge radius, will involve the so-called size effect. In this study, a developed 2D cutting simulation that incorporates deposition residual stresses was applied to evaluate the size effect, at different cutting speeds, on the tool stresses, tool temperatures, specific cutting energy as well as the interface stresses around a cutting edge. The size effect on the radial normal stress is more noticeable at a low speed. In particular, a large uncut chip thickness has a substantially lower stress. On the other hand, the size effect on the circumferential normal stress is more noticeable at a high speed. At a small uncut chip thickness, the stress is largely compressive.

A Machining Science Approach to Dental Cutting of Glass Ceramics Using an Electric Handpiece and Diamond Burs

2013 ◽  
Vol 135 (1) ◽  
Author(s):  
Xiao-Fei Song ◽  
Jian-Hui Peng ◽  
Ling Yin ◽  
Bin Lin
Keyword(s):  
Surface Roughness ◽  
Cutting Forces ◽  
High Speed ◽  
Removal Rate ◽  
Chip Thickness ◽  
Glass Ceramics ◽  
Specific Cutting Energy ◽  
Dental Ceramics ◽  
Cutting Energy ◽  
Specific Material

Dental cutting using handpieces has been the art of dentists in restorative dentistry. This paper reports on the scientific approach of dental cutting of two dental ceramics using a high-speed electric handpiece and coarse diamond burs in simulated clinical conditions. Cutting characteristics (forces, force ratios, specific removal energy, surface roughness, and morphology) of feldspar and leucite glass ceramics were investigated as functions of the specific material removal rate, Qw and the maximum undeformed chip thickness, hmax. The results show that up and down cutting remarkably affected cutting forces, force ratios, and specific cutting energy but did not affect surface roughness and morphology. Down cutting resulted in much lower tangential and normal forces, and specific cutting energy, but higher force ratios. The cutting forces increased with the Qw and hmax while the specific cutting energy decreased with the Qw and hmax. The force ratios and surface roughness showed no correlations with the Qw and hmax. Surface morphology indicates that the machined surfaces contained plastically flowed and brittle fracture regions at any Qw and hmax. Better surface quality was achieved at the lower Qw and the smaller hmax. These results provide fundamental data and a scientific understanding of ceramic cutting using electric dental handpieces in dental practice.

Experimental Evaluations of High/Ultra-High Speed Grinding of Tungsten Carbide

2014 ◽  
Vol 575 ◽  
pp. 350-354
Author(s):  
Zhen Tao Shang ◽  
Ying Jia
Keyword(s):  
Surface Roughness ◽  
Process Parameters ◽  
High Speed ◽  
Chip Thickness ◽  
Cemented Carbides ◽  
Grinding Process ◽  
Grinding Forces ◽  
Undeformed Chip Thickness ◽  
High Speed Grinding ◽  
Experimental Researches

According to broken edges and cracks emerging in traditionally machining cemented carbides (CP1) materials, this paper carried out some experimental researches on high and ultra-high grinding process for these materials, and considered the effect of process parameters on grinding forces, surface roughness, surface quality; discusses the calculation of the single grinding average normals force and relationship with maximum undeformed chip thickness and theoretical critical normal loads; probes the removal mechanisms of cemented carbide in high/ultra-high grinding process.

Influence of Material Flow Stress on Surface Roughness in High-Speed Machining

2012 ◽  
Vol 723 ◽  
pp. 219-224
Author(s):  
Su Yu Wang ◽  
Wen Jie Yang ◽  
Wen Chao Wang
Keyword(s):  
Surface Roughness ◽  
Flow Stress ◽  
Material Flow ◽  
High Speed ◽  
Vertical Direction ◽  
Contact Theory ◽  
High Speed Machining ◽  
Machined Surface ◽  
Simulation Based ◽  
Side Flow

A mechanical model of surface roughness is established based on the Kragelskii-Drujanov theory of friction and wear and Hertz elastic contact theory. Effect of material flow stress on remnant height of the machined surface was investigated. Test showed that the machined surface morphology provides the phenomena of the side flow in the vertical direction of ploughing in high-speed machining. The remnant height values on the machined surface of the high-speed machining are obtained by DEFORM-3D simulation. Based on the results it can be concluded that the surface roughness values of the workpiece increase with material flow stress.

Analysis of Roughness in Super-High Speed Point Grinding

2010 ◽  
Vol 126-128 ◽  
pp. 101-106
Author(s):  
Yue Ming Liu ◽  
Ya Dong Gong ◽  
Jun Cheng ◽  
Ting Chao Han
Keyword(s):  
Surface Roughness ◽  
Probability Distribution ◽  
Theoretical Analysis ◽  
Contact Area ◽  
High Speed ◽  
Chip Thickness ◽  
New Method ◽  
Swivel Angle ◽  
Component Manufacturing

The technology of super-high speed point (SHSP) grinding will bring in higher precision and productivity for component manufacturing. The surface roughness attained by SHSP grinding is analyzed in this paper based on the contact area and the probability distribution of chip thickness while the swivel angle of α exists, proposing a new method to predicate the value of the roughness, the experiment of SHSP grinding is carried out whether α exists or not to verify the theoretical analysis in the paper, through observing the micro-surface after grinding, the conclusions will be drawn at last.

Influence of Chip Curl on Tool-Chip Contact Length in High Speed Machining

2009 ◽  
Vol 626-627 ◽  
pp. 71-74 ◽  
Author(s):  
Xue Feng Bi ◽  
G. Sutter ◽  
Gautier List ◽  
Yong Xian Liu
Keyword(s):  
High Speed ◽  
Cutting Speed ◽  
Chip Thickness ◽  
Contact Length ◽  
Radius Of Curvature ◽  
High Speed Machining ◽  
Uncut Chip Thickness ◽  
High Cutting Speed ◽  
Chip Formation Mechanism ◽  
The Relationship

The tool-chip contact length, as an important parameter controlling the geometry of tool crater wear and understanding chip formation mechanism, is widely investigated in machining. The aim of this paper is to study the influence of chip curl on tool-chip contact length by means of experimental observations with high cutting speed. The relationship between tool-chip contact length, chip radius of curvature and uncut chip thickness was investigated. Experimental results show the effect of increasing spiral chip radius on tool-chip contact length with low uncut chip thickness in high speed machining.

Experimental Study on Specific Shear Energy in High-Speed Machining 7050-T7451

2013 ◽  
Vol 589-590 ◽  
pp. 8-12
Author(s):  
Guo Sheng Su ◽  
Zhan Qiang Liu
Keyword(s):  
Experimental Study ◽  
High Speed ◽  
Cutting Tool ◽  
Cutting Speed ◽  
Chip Thickness ◽  
Rake Angle ◽  
Thermal Softening ◽  
High Speed Machining ◽  
Uncut Chip Thickness ◽  
Shear Energy

In this paper, the specific shear energy in high-speed machining 7050-T7451 from 100m/min to 3000m/min is measured and compared with the theoretical value evaluated by the method proposed by Pawade et al. (2009). The influences of cutting speed, rake angle of cutting tool, and uncut chip thickness are also investigated and discussed. Results show that the specific shear energy decreases with the increase of cutting speed, rake angle, and uncut chip thickness. The higher thermal softening makes the specific shear energy lower.

Enhancement of EDM Performance by Using Copper-Silver Composite Electrode

2020 ◽  
Vol 38 (9A) ◽  
pp. 1352-1358
Author(s):  
Saad K. Shather ◽  
Abbas A. Ibrahim ◽  
Zainab H. Mohsein ◽  
Omar H. Hassoon
Keyword(s):  
Surface Roughness ◽  
Material Removal Rate ◽  
Material Removal ◽  
High Speed ◽  
Composite Electrode ◽  
Removal Rate ◽  
Pure Copper ◽  
High Speed Steel ◽  
Pulse On Time ◽  
Pulse Off Time

Discharge Machining is a non-traditional machining technique and usually applied for hard metals and complex shapes that difficult to machining in the traditional cutting process. This process depends on different parameters that can affect the material removal rate and surface roughness. The electrode material is one of the important parameters in Electro –Discharge Machining (EDM). In this paper, the experimental work carried out by using a composite material electrode and the workpiece material from a high-speed steel plate. The cutting conditions: current (10 Amps, 12 Amps, 14 Amps), pulse on time (100 µs, 150 µs, 200 µs), pulse off time 25 µs, casting technique has been carried out to prepare the composite electrodes copper-sliver. The experimental results showed that Copper-Sliver (weight ratio70:30) gives better results than commonly electrode copper, Material Removal Rate (MRR) Copper-Sliver composite electrode reach to 0.225 gm/min higher than the pure Copper electrode. The lower value of the tool wear rate achieved with the composite electrode is 0.0001 gm/min. The surface roughness of the workpiece improved with a composite electrode compared with the pure electrode.

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