An Experimental Evaluation of Laser-Assisted Micromilling of Two Difficult to Machine Alloys

2008 ◽  
Author(s):  
Jonathan A. Shelton ◽  
Yung C. Shin
Keyword(s):  
Material Removal ◽  
Bulk Material ◽  
Three Dimensional ◽  
Acoustic Emissions ◽  
Micro Milling ◽  
Depth Of Cut ◽  
Material Strength ◽  
Machined Surface ◽  
Macro Scale ◽  
Localized Heating

Micro-milling can be difficult to apply to many engineering materials due to a variety of scaling induced factors including: low cutting speeds, high relative tool deflections and runout, and increased material strength at smaller size scales. Additionally, edge burrs which can easily be removed after macro scale milling must be avoided in micro-milling due to the lack of available finishing operations. Laser assisted machining (LAM) involves localized heating of the work material prior to the cutting tool. This localized heating thermally weakens the workpiece resulting in lower cutting forces, improved surface finish, and longer tool life. Applying this concept to micro-milling offers the opportunity for process improvements, especially with materials which are considered difficult to machine. Laser assisted micro-milling (LAMM) was evaluated on Ti-6Al-4V and 316 stainless steel alloys using 100 μm diameter endmills in slotting operations. Micro-scale laser-material interactions were first studied with bulk material absorptivity being determined experimentally through a novel technique utilizing several calibrated melting mediums. A three-dimensional transient finite volume based thermal model was then used to analytically predict appropriate process parameters on the basis of material removal temperatures. A thorough investigation of acoustic emissions (AE) during LAMM was performed. In particular, the effects of depth of cut, tool wear, and material removal temperature on the RMS of AE were studied. Additionally, the effect of LAMM on the machined surface was evaluated quantitatively.

Experimental Evaluation of Laser-Assisted Micromilling in a Slotting Configuration

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
Jonathan A. Shelton ◽  
Yung C. Shin
Keyword(s):  
Material Removal ◽  
Three Dimensional ◽  
Chip Thickness ◽  
Acoustic Emissions ◽  
Element Model ◽  
Depth Of Cut ◽  
Material Strength ◽  
Machined Surface ◽  
Dimensional Finite Element ◽  
Aisi 316

Micromilling can be difficult to apply to many engineering materials due to a variety of scaling induced factors including low cutting speeds, high relative tool deflections and runout, and increased material strength at smaller size scales. To alleviate these problems, laser-assisted micromilling (LAMM) was evaluated on Ti6Al4V, AISI 422, and AISI 316 using 100 μm diameter endmills in slotting operations. A three-dimensional transient finite-volume based thermal model was used to analytically predict appropriate process parameters on the basis of material removal temperatures. A two-dimensional finite element model was created and used to show the effects of cutting edge radius, uncut chip thickness, and material removal temperature on the cutting force. A thorough experimental investigation of acoustic emissions (AEs) during LAMM was performed. In particular, the effects of depth of cut, tool wear, and material removal temperature on the root-mean-square of AEs were studied. The effects of LAMM on the machined surface finish and edge burrs were also evaluated.

scholarly journals Increasing strength of FFF three-dimensional printed parts by influencing on temperature-related parameters of the process

2020 ◽  
Vol 26 (1) ◽  
pp. 107-121 ◽  
Author(s):  
Vladimir E. Kuznetsov ◽  
Alexey N. Solonin ◽  
Azamat Tavitov ◽  
Oleg Urzhumtsev ◽  
Anna Vakulik
Keyword(s):  
Bulk Material ◽  
Three Dimensional ◽  
Fracture Load ◽  
Bending Test ◽  
Material Strength ◽  
Thermal Imager ◽  
Fused Filament Fabrication ◽  
Content Type ◽  
Temperature Conditions ◽  
Two Factors

Purpose This paper aims to investigate how the user-controlled parameters of the fused filament fabrication three-dimensional printing process define temperature conditions on the boundary between layers of the part being fabricated and how these conditions influence the structure and strength of the polylactic acid part. Design/methodology/approach Fracture load in a three-point bending test and calculated related stress were used as a measure. The samples were printed with the long side along the z-axis, thus, in the bend tests, the maximum stress occurred orthogonally to the layers. Temperature distribution on the sample surface during printing was monitored with a thermal imager. Sample mesostructure was analyzed using scanning electron microscopy. The influence of the extrusion temperature, the intensity of part cooling, the printing speed and the time between printing individual layers were considered. Findings It is shown that the optimization of the process parameters responsible for temperature conditions makes it possible to approximate the strength of the interlayer cohesion to the bulk material strength. Originality/value The novelty of the study consists in the generalization of the outcomes. All the parameters varied can be expressed through two factors, namely, the temperature of the previous layer and the extrusion efficiency, determining the ratio of the amount of extruded plastic to the calculated. A regression model was proposed that describes the effect of the two factors on the printed part strength. Along with interlayer bonding strength, these two factors determine the formation of the part mesostructure (the geometry of the boundaries between individual threads).

Cutting Force Analysis of on-Machine Fabricated PCD Tool during Glass Micro-Grinding

2011 ◽  
Vol 264-265 ◽  
pp. 1085-1090 ◽  
Author(s):  
Asma Perveen ◽  
Muhammad Pervej Jahan ◽  
Yoke San Wong ◽  
Mustafizur Rahman
Keyword(s):  
Cutting Force ◽  
Cutting Forces ◽  
Material Removal ◽  
Depth Of Cut ◽  
Machined Surface ◽  
Hard Materials ◽  
Pcd Tool ◽  
Fluidic Devices ◽  
Micro Machine ◽  
Poly Crystalline Diamond

Brittle and hard materials are problematic to mechanically micro machine due to damage resulting from material removal by brittle fracture, cutting force-induced tool deflection or breakage and tool wear. As a result, the forces arising from the cutting process are important parameter for material removal. This study was undertaken to investigate the effect of cutting conditions on cutting forces and the machined surface during the glass micro grinding using on-machine fabricated (Poly Crystalline Diamond) PCD tool. Experimental results showed that an increase in depth of cut and feed rate can result in increase of cutting forces and surface roughness as well. Among the forces in 3 axes, force along feed direction is found to be larger, which played a major role in material removal. Finally, it is observed that PCD tool exhibits promising behaviour to machine brittle material like BK-7 glass for producing micro molds and micro fluidic devices, since it has better wear resistance, experiences less cutting forces and generates smooth surfaces with Ra value of as low as 12.79 nm.

Faster and More Efficient FIB Sample Preparation: Exploring Single-Raster Staircase Patterning at Glancing Angle of Incidence

2020 ◽  
Author(s):  
Joseph Favata ◽  
Valery Ray ◽  
Sina Shahbazmohamadi
Keyword(s):  
Sample Preparation ◽  
Material Removal ◽  
Bulk Material ◽  
Ion Beam ◽  
Process Time ◽  
Depth Of Cut ◽  
Angle Of Incidence ◽  
Glancing Angle ◽  
Beam Incidence ◽  
Slope Direction

Abstract Focused Ion Beam sample preparation for electron microscopy often requires large volumes of material to be removed. Prior efforts to increase the rate of bulk material removal were mainly focused on increasing the primary ion beam current. Enhanced sputtering yield at glancing ion beam incidence is known, but has not found widespread use in practical applications. In this study, etching at glancing ion beam incidence was explored for its advantages in increasing the rate of bulk material removal. Anomalous enhancement of material removal was observed with single raster etching in along-the-slope direction with toward-FIB raster propagation at glancing ion beam incidence. Material removal was inhibited with raster propagation away from FIB. The effects of glancing angle and ion dose on depth of cut and volume of removed material were also recorded. We demonstrated that the combination of single-raster etching in along-the-slope direction by raster propagating toward-FIB at glancing incidence and a “staircase” type of etching strategy holds promise for reducing the process time for bulk material removal in FIB sample preparation applications.

Principal Curvature Alignment Technique for Machining Complex Surfaces

1997 ◽  
Vol 119 (4B) ◽  
pp. 756-765 ◽  
Author(s):  
S. Bedi ◽  
S. Gravelle ◽  
Y. H. Chen
Keyword(s):  
Surface Finish ◽  
Principal Curvature ◽  
Material Removal ◽  
Principal Axis ◽  
Three Dimensional ◽  
Complex Surfaces ◽  
Machined Surface ◽  
Scallop Height ◽  
Alignment Technique

Machining complex three dimensional surfaces is a challenging task. This paper presents two methods of machining these surfaces on a 4 and 5 axis machine, using a toroidal shaped cutter. The methods propose to align the principal axis of curvature of the machining surface with that of the machined surface in order to increase the volume of material removed. The increase in material removal at a point reduces the scallop height. Thus, fewer passes are required to achieve the same surface finish.

Investigation of Grinding Characteristics of Cemented Carbides YL10.2 and YF06

2014 ◽  
Vol 1017 ◽  
pp. 104-108 ◽  
Author(s):  
Tao Xu ◽  
Jian Wu Yu ◽  
Zhong Jian Zhang ◽  
Jian Gang Tu ◽  
Xiang Zhong Liu ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Material Removal ◽  
Ground Surface ◽  
Grinding Force ◽  
Cemented Carbides ◽  
Depth Of Cut ◽  
Grinding Wheel ◽  
Machined Surface ◽  
Ultrafine Grained ◽  
Machined Surface Roughness

YL10.2 and YF06 are ultrafine-grained cemented carbides, and grinding experiments were carried out with resin-bonded diamond grinding wheel. Based on measured grinding force, surface roughness and SEM topography, experimental results were analyzed; grinding forces and depth of grinding approach linear correlation; and the grinding force of YF06 is greater than that of YL10.2 in rough grinding, but the grinding force increases significantly if depth of cut is greater than a certain value in finish grinding. The trend of machined surface roughness looks like “V” type with the increasing of depth of cut; the material removal behavior of ultrafine-grained cemented carbides in grinding was observed; the ploughing and fragmentation exist simultaneously on the ground surface, and the dominated material removal behavior depends on the grinding parameters or chemical composition of workpiece.

scholarly journals Research on High Performance Milling of Engineering Ceramics from the Perspective of Cutting Variables Setting

Materials ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 122
Author(s):  
Rong Bian ◽  
Wenzheng Ding ◽  
Shuqing Liu ◽  
Ning He
Keyword(s):  
Material Removal ◽  
High Performance ◽  
Removal Rate ◽  
Chip Thickness ◽  
Depth Of Cut ◽  
End Mill ◽  
Uncut Chip Thickness ◽  
Machined Surface ◽  
Milling Parameters ◽  
Corner Radius

The setting of cutting variables for precision milling of ceramics is important to both the machined surface quality and material removal rate (MRR). This work specifically aims at the performance of corner radius PCD (polycrystalline diamond) end mill in precision milling of zirconia ceramics with relatively big cutting parameters. The characteristics of the cutting zone in precision milling ceramics with corner radius end mill are analyzed. The relationships between the maximum uncut chip thickness (hmax) and the milling parameters including feed per tooth (fz), axial depth of cut (ap) and tool corner radius (rε) are discussed. Precision milling experiments with exploratory milling parameters that cause uncut chip thickness larger than the critical value were carried out. The material removal mechanism was also analyzed. According to the results, it is advisable to increase fz appropriately during precision milling ZrO2 ceramics with corner radius end mill. There is still a chance to obtain ductile processed surface, as long as the brittle failure area is controlled within a certain range. The appropriate increasing of ap, not only can prevent the brittle damage from affecting the machined surface, but also could increase the MRR. The milling force increases with increasing MRR, but the surface roughness can still be stabilized within a certain range.

Cutting Parameters Impacting on Tool Wear in Micro End-milling of Tool Steel

2018 ◽  
Author(s):  
Cínthia Soares Manso ◽  
Cleiton Lazaro Fazolo de Assis ◽  
Luciana Wasnievski da Silva de Luca Ramos ◽  
Erik Gustavo Del Conte
Keyword(s):  
Tool Wear ◽  
Tool Steel ◽  
End Milling ◽  
Cutting Parameters ◽  
Milling Process ◽  
Micro Milling ◽  
Depth Of Cut ◽  
Nose Radius ◽  
Machined Surface ◽  
Tool Diameter

In micro milling process, the quick wear and premature breakage of tools configure a problem that affects not only the process costs but also the manufacturing quality. This work investigates the influence of the cutting parameters on tool wear and surface roughness in a dry machining of a tool steel H13 workpiece (X40CrMoV5-1). Spindle speed was kept constant (27200 rpm) and two feeds per tooth were applied (1.5 and 3.0 µm) as depth of cut (25 and 30 µm), and variating cut length as well. The wear of the tool top area, tool diameter and nose radius were monitored during micro milling tests. Roughness was evaluated by using a Laser Confocal Microscope. The lower level of feed per tooth and depth of cut showed lower roughness, but a higher tool wear. A balance between cutting parameters and cutting length must be considered to ensure micromachining without severe tool wear and preserve microchannel features along its machined surface.

Mechanism of Brittle-Ductile Transition of Single Silicon Wafer Using Nanoindentation Techniques

2008 ◽  
Vol 375-376 ◽  
pp. 52-56 ◽  
Author(s):  
Yu Li Sun ◽  
Dun Wen Zuo ◽  
Duo Sheng Li ◽  
Rong Fa Chen ◽  
Min Wang
Keyword(s):  
Fracture Toughness ◽  
Elastic Modulus ◽  
Silicon Wafer ◽  
Material Removal ◽  
Bulk Material ◽  
Scratch Resistance ◽  
Depth Of Cut ◽  
Scratch Depth ◽  
Brittle Ductile Transition ◽  
Critical Depth Of Cut

Hardness, elastic modulus and scratch resistance of single silicon wafer are measured by nanoindentation and nanoscratching using a nanoindenter. Fracture toughness is measured by indentation using a Vickers indenter. The results show that the hardness and elastic modulus at a peak indentation depth of 100 nm are 12.6 and 166.5 GPa respectively. These values reflect the properties of the silicon wafer, the bulk material. The fracture toughness value of the silicon wafer is 0.74 Mpa·m1/2. The material removal mechanisms are seen to be directly related to the normal force on the tip. The critical load and scratch depth estimated from the scratch depth profile after the scratching and the friction profile are 138.64 mN and 54.63 nm respectively. If the load and scratch depth are under the critical values, the silicon wafer will undergo plastic flow rather than fracture. The critical scratch depth is different from that calculated from the formula of critical-depth-of-cut described by Bifnao et al and some reasons are given.

Optimization of Cutting Parameters and Burrs Control with PMMA Coating in Micro-Milling Titanium Alloys

2016 ◽  
Vol 836-837 ◽  
pp. 191-197 ◽  
Author(s):  
Yu Chao Li ◽  
Zhan Qiang Liu ◽  
Yu Kui Cai ◽  
Zhao Jun Kou
Keyword(s):  
Titanium Alloy ◽  
Cutting Parameters ◽  
Optical Microscope ◽  
Machining Process ◽  
Micro Milling ◽  
Depth Of Cut ◽  
Machined Surface ◽  
Workpiece Surface ◽  
Coating Method ◽  
Optimization Of Cutting Parameters

Fabrication of microchannels on titanium alloy with micro-milling is a tough challenge due to the difficultly to remove the burrs formed in machining process. A novel method to gelatinize workpiece surface to control the generation of burr as well as the optimization of cutting parameters are investigated in this paper. Differences existed between the process of micro-milling and that of traditional milling can be accounted for size effect. Influences of feed per tooth, depth of cut and spindle speed on the formation of burr were taken into consideration respectively by single factor method. The topographies of the machined surface with micro-milling were observed and measured by optical microscope. Results showed that the dimensions of burrs increased with the rise of depth of cut. However, it decreased initially, then increased later with the augment of feed per tooth. Sacrifice layer with PMMA was coated and gelatinized on the workpiece surface, which could restrain the plastic deformation of materials during titanium alloy micro-milling. The experimental results presented that the dimensions of burr could reduce greatly by the proposed PMMA coating method compared to materials without coating.

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