Relief Angle Research Articles

엔드밀 가공시 주축 오리엔테이션 기능을 통한 공구마멸 보정 장치의 개발

The most important thing in measuring the tool wear is to set up the measurement base.The end mill that is being used for machning of die is difficult to set up the base and to measure the toll wear because of eometric properties of that such as a helix and relief angle. In this study , a new instrument using spindle orientation functionin end milling is developed to measure the tool wear and evaluated by the measuring system on the machine. Finally, this new method makes possible the wear measurement of same position and reduces the measuring time compared with the measuring methods such as the microscope and CCD.

The mechanisms of bell mouth formation in gundrilling when the drill rotates and the workpiece is stationary. Part 2: the second stage of drill entrance

This paper reveals the main design and technological factors affecting entrance stability and provides practical recommendations on the design of gundrills. The subject has been covered in two parts. In the first part of this paper, the first stage of drill entrance, which begins when the gundrill touches the face of the workpiece and ends when the gundrill’s cutting edges are fully engaged in cutting, is considered. The role of the clearance in the starting bush and the design of the gundrill’s supporting area are analyzed. In this paper, the second stage of gundrill entrance is analyzed. The system engineering approach, which includes the time axis, is used in the consideration of distinctive steps in the drill entrance. The influence of the design parameter of the gundrill (such as relative location of the supporting area and the cutting edges, flank (relief) angle of the outer cutting edge, the location of the rake face, design and location of the supporting area) as well as the clearance in the starting bush on the duration of entrance instability is discussed. A number of practical suggestions to increase the entrance stability are provided.

Surface relief effects of α precipitates in a Ti–Mo alloy

The characteristics of the formation of surface relief associated with h.c.p. α precipitates in a Ti–Mo alloy were studied by atomic force microscopy coupled with electron back scattering diffraction and three-dimensional morphological observation. Tent- or inverse tent-shaped relief was formed with normal α plates (thick plates formed often with a ragged interface at smaller undercoolings) progressively to a lesser extent with decreasing temperature. It was replaced entirely by invariant plane strain (IPS) type relief as the plate morphology evolved to black plates (thin straight plates formed at larger undercoolings). In contrast to IPS relief the tilt angles of tent- and inverse tent-shaped relief were often considerably greater than expected from the motion of biatomic structural ledges. There seems to be a marked correlation of relief type with the surface orientation of matrix grains. A phenomenological explanation is presented for unduly large relief angles on the basis of previous theories.

Hillslope evolution by nonlinear, slope‐dependent transport: Steady state morphology and equilibrium adjustment timescales

Soil‐mantled hillslopes are typically convex near the crest and become increasingly planar downslope, consistent with nonlinear, slope‐dependent sediment transport models. In contrast to the widely used linear transport model (in which sediment flux is proportional to slope angle), nonlinear models imply that sediment flux should increase rapidly as hillslope gradient approaches a critical value. Here we explore how nonlinear transport influences hillslope evolution and introduce a dimensionless parameter ΨLto express the relative importance of nonlinear transport. For steady state hillslopes, with increasing ΨL(i.e., as slope angles approach the threshold angle and the relative magnitude of nonlinear transport increases), the zone of hillslope convexity becomes focused at the hilltop and side slopes become increasingly planar. On steep slopes, rapid increases in sediment flux near the critical gradient limit further steepening, such that hillslope relief and slope angle are not sensitive indicators of erosion rate. Using a one‐dimensional finite difference model, we quantify hillslope response to changes in baselevel lowering and/or climate‐related transport efficiency and use an exponential decay function to describe how rapidly sediment flux and erosion rate approach equilibrium. The exponential timescale for hillslope adjustment decreases rapidly with increasing ΨL. Our results demonstrate that the adjustment timescale for hillslopes characteristic of the Oregon Coast Range and similar steep, soil‐mantled landscapes is relatively rapid (≤50 kyr), less than one quarter of the timescale predicted by the linear transport model.

Observation of bainite surface reliefs in Fe–C alloy by atomic force microscopy

Atomic force microscopy was employed to study the reliefs (undulations) at the pre-polished surface resulting from the transformation of austenite to bainite in an Fe–0.33C–3.0Mn–2.15Si–1.25Ni (wt.%) alloy. All the surface reliefs observed were shown to be tent-shaped, which was confirmed by the observation of corresponding microstructure of surface relief region after etching. The widths of surface reliefs are close to those of the bainite plates, indicating no significant plastic deformation of adjacent matrix. The measured surface relief angles agree well with the prediction of diffusion controlled ledgewise growth theory.

Thermoelastic Martensitic Transformation and Shape Memory Effect in Sr2(Si, Ge)O4.

Crystals of Sr2(Si1-xGex)O4 with 0≤x≤1 were prepared and examined by powder XRD, optical microscopy, and AFM. The crystals with 0.3≤x≤0.6 were composed of both the α′ (orthorhombic)- and twinned β (monoclinic)-phases. On the basis of the lattice correspondence between the two phases and their cell parameters, the phenomenological crystallographic theory has been applied to determine the habit planes and shape deformations upon α′-to-β martensitic transformation. The habit planes, which define the coherent interphase boundaries between α′ and β, were nearly parallel to either (100) or (001). Because the transformation was accompanied by a small volumetric shrinkage of -0.3%, the parent α′-phase would elastically accommodate the strains upon the polysynthetic twin formation of the β-phase. At 293K, the crystals with x=0.6 were composed of -92.5mass%α′ and -7.5mass%β. During further cooling in liquid nitrogen, the α′-to-β transformation proceeded which increases the phase composition of β up to -56.3%. The transformation is accompanied by the formation of plate-like surface reliefs. The surface relief angles have been determined from both observations (7.4±0.2°) and calculations based on a phenomenological analysis (7.55°). The fair agreement of these values indicates that the transformation is martensitic and mainly governed by a shear mechanism. The shape memory effect has been demonstrated by the reproducibility of the surface reliefs. The coherency at the interface boundaries between the α′ and β-phases as well as the effective strain accommodation substantially account for the thermoelasticity of the solid solutions.

Gear-Cutting Tool for Screw-Compressor Rotors

A built-up hob for a screw-compressor rotor is proposed. The hob is composed of cutter blades and a hob head. The blade is cut out from a tempered planar plate of high speed tool steel by wire-cut electrodischarge machining (EDM). During the wire cutting process, the wire electrode has a fixed angle to ensure both the side and the end relief angle of the cutting edge, so that the rake face regrinding sharpens the cutting edge without changing the profile of the rake face. In other words, theoretically, the hob has no accuracy deterioration due to rake face regrinding. The formulae of rack tooth profile are derived from the female rotor tooth profile expressed by numerical formulae. Next, the fundamental helicoid of the hob and the profile of the cutting edge of the blade are calculated. The hob was fabricated and the rotor hobbing was carried out.

F-0516 純チタンの切削加工 : 表面あらさの向上について(S40-2 難削材の加工(2))(S40 難削材の加工)

In the case of pure titanium machining with various cutting speeds, the effects of cutting tool materials and shape on surface finish of workpieces are investigated experimentally in this paper. Tool materials used in this machining experiments are cemented carbides (K10,20), ceramic, cerment and CBN tool. Also, rake angle, side relief angle and nose radius of tool are variously changed m this research. In these tool materials because of the goodness of surface finish Surface finish produced by positive rake tool is better than that by negative rake tool due to the goodness of chip drawing.

Surface Relief Induced by Martensitic Transformation in Phosphorus‐Bearing Dicalcium Silicate

Crystals of (Ca1.955□0.045)(Si0.91P0.09)O4, where □ denotes a vacancy, have been prepared and examined by XRD, optical microscopy, SEM, and AFM. At 20°C, the crystals are composed of 38%α′L and 62%β phases. Upon cooling to −185°C, the α′L‐ to β‐phase transformation occurs, which increases the β‐phase composition to 72%. The transformation is also accompanied by the formation of platelike surface reliefs. The surface relief angles have been determined from observations (7.9°± 0.2°) and calculations based on a phenomenological analysis (7.84°). The fair agreement of these values indicates that the transformation is martensitic and mainly governed by a shear mechanism.

Gear-Cutting Tool for Screw-Compressor Rotors. Built-up Hob.

A built-up hob for a screw-compressor rotor is proposed. The hob is composed of cutter blades and a hob head. The blade is cut out from a tempering planar plate of high speed tool steel by wire-cut electric discharge machining. During the wire cutting process, the wire electrode has a fixed angle to ensure both the side and the end relief angle of the cutting edge, so that the rake face regrinding sharpens the cutting edge without changing the profile of the rake face. The formulae of rack tooth profile are derived from the female rotor tooth profile expressed by numerical formulae. Then, the fundamental helicoid of the hob and the profile of the cutting edge of the blade are calculated. The hob was made and the rotor hobbing was carried out.

Origin of 3.45 Ga coniform stromatolites in Warrawoona Group, Western Australia

Research Article| August 01, 1999 Origin of 3.45 Ga coniform stromatolites in Warrawoona Group, Western Australia H. J. Hofmann; H. J. Hofmann 1Department of Geology, University of Montreal, P.O. Box 6128, Station A, Montreal, Quebec H3C 3J7, Canada Search for other works by this author on: GSW Google Scholar K. Grey; K. Grey 2Geological Survey of Western Australia, 100 Plain Street, East Perth 6004, Western Australia, Australia Search for other works by this author on: GSW Google Scholar A. H. Hickman; A. H. Hickman 2Geological Survey of Western Australia, 100 Plain Street, East Perth 6004, Western Australia, Australia Search for other works by this author on: GSW Google Scholar R. I. Thorpe R. I. Thorpe 3Geological Survey of Canada, 601 Booth Street, Ottawa, Ontario K1A 0E8, Canada Search for other works by this author on: GSW Google Scholar GSA Bulletin (1999) 111 (8): 1256–1262. https://doi.org/10.1130/0016-7606(1999)111<1256:OOGCSI>2.3.CO;2 Article history first online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation H. J. Hofmann, K. Grey, A. H. Hickman, R. I. Thorpe; Origin of 3.45 Ga coniform stromatolites in Warrawoona Group, Western Australia. GSA Bulletin 1999;; 111 (8): 1256–1262. doi: https://doi.org/10.1130/0016-7606(1999)111<1256:OOGCSI>2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract A new occurrence of conical and branched pseudocolumnar stromatolites in Archean dolostones in the Pilbara region, Australia, contributes significant new morphologic information on such structures. These remains are interpreted as probably representing, in part, microbially mediated accretionary growth surfaces in an Archean hypersaline depositional basin. The structures comprise laterally linked pseudocolumns of centimeter width and decimeter height, with first-order conical laminae of as much as 15 cm of synoptic relief and apical angles of 30°–80°. The conical laminae are modified by a second-order, centimeter-scale, low-amplitude primary corrugate lamination, with crests and troughs occasionally stacked to form satellitic, obliquely directed pseudocolumns; bedding surfaces exhibit a preferred direction of elongation of the cones, an orientation that is orthogonal (and unrelated) to the trend of younger folding; the microstructure is secondary. The stromatolites are better preserved than those previously known from chert in the Warrawoona succession. The remains exhibit certain distinct morphologic attributes corresponding to those in younger stromatolites, such as displayed by Thyssagetes and Jacutophyton, whose biogenicity is generally accepted (although difficult to demonstrate conclusively); the conical Warrawoona forms may represent the oldest known precursor of these taxa. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Influence of Hob Geometry on Tool Wear Reduction Effect of Lubricating Additives in Cutting Oil.

This paper deals with the influence of hob geometry, rake angle and relief angle, on tool wear reduction effect of lubricating additives in cutting oils for bobbing and effect of the additives for improving of finished surface roughness. Experiments were carried out using a fly tool. It was revealed that among the additives used in these experiments, sulfur type's sulfurized fatty oil showed a best performance in terms of an extension of tool life and an improvement of surface roughness for almost of rake angles, relief angles and at all cutting speeds tested. Especially, it was obvious that the sulfurous EP additive is effective for the hob having the geometry of rake angle of 0° and relief angle of 12°. The use of sulfurized fatty oil as an additive is very effective for environmental pollution control and for improving the safety of the operator.

Drilling Burr Formation in Titanium Alloy, Ti-6AI-4V

Titanium alloy (Ti-6AI-4V) plates were drilled to investigate the effects of tool geometry as well as process conditions on the drilling burr formation. Drilling was done with solid carbide tools with and without coolant and high speed cobalt drills without coolant. Four distinct burr types were observed. During dry cutting, a “rolled back” type burr was observed at high feed rates and cutting speeds and is believed to be due to thermal effects. A “ring” type burr was observed when drilling with coolant. While cutting conditions had little effect on the burr sizes formed, drill geometry (helix angle, split point vs. helical point, lip relief angle and point angle) affected burr thickness and height.

Interpretation of size effect in orthogonal machining of composite materials. Part I: Unidirectional glass-fibre-reinforced plastics

Abstract Orthogonal cutting tests were carried out on unidirectional glass-fibre-reinforced plastics, using high-speed steel tools. During the tests, the tool rake and relief angle, and the depth of cut t were varied, whereas the cutting direction was held parallel to the fibre orientation. The trend of the principal forces recorded during cutting clearly showed the so-called `size effect': the unit cutting force (also known as `specific energy') was a decreasing function of the depth of cut, tending to infinity for vanishingly small values of t. A previous force scheme, assuming a significant influence of the friction generated by the work material sliding along the tool flank on the overall cutting forces, was utilized to interpret the cutting data, and to differently define the unit cutting force. According to the model, the unit cutting force and the coefficient of friction were independent of both the relief angle and the depth of cut, although the former, as expected, sensibly decreased with increasing the rake angle.

Interpretation of size effect in orthogonal machining of composite materials. Part II. Sheet moulding compound

Long-term orthogonal cutting tests were carried out on sheet moulding compound, using high speed steel tools with 0° rake and 5° relief angle and a constant depth of cut, in order to verify the effect of tool wear on cutting forces. The tests were periodically interrupted, and the variation of cutting forces as a function of depth of cut at various degrees of wear was measured. It was observed that the thrust force is much more sensitive to wear than the principal one. The tool wear features suggested negligible sliding of the chip against the tool face, and intense friction along the tool flank, in agreement with previous results concerning the machining of unidirectional carbon-fibre-reinforced plastics. Accordingly, a force model previously proposed for unidirectional composites was applied to the cutting data. It was found that the increase in the principal force with wear is attributable to the increase in the thrust force generated at the tool flank, whereas the force arising at the tool face is substantially unaffected by tool wear. This allowed for the definition of a unit cutting force independent of both the depth of cut and the tool wear.

Investigation of surface relief accompanying Widmanstatten ferrite formation by scanning tunneling microscopy

The evolution and formation mechanism of surface nanorelief associated with martensitic twin colony (MTC) in Mn-based alloy are studied by use of the phase-field finite element method. The calculation results show that the maximum height of nanorelief is about 30 nm and the maximum nanorelief angle is about 3.2°. The MTC can form during the microstructure evolution. The nanorelief in the same MTC or in different MTCs with the same orientation may have the similar features, which is different from that in the adjacent MTC. The top and bottom edges of one nanorelief correspond to different martensite twin boundaries (MTBs). A bigger stress and a higher plastic deformation distribute around MTC interface than MTB, and the interfacial migration of MTC is greater than MTB. The grain orientation and external stress directly affect the nanorelief and MTC. The biclinic nanorelief (tent-shape and V-shape) evolves from the monoclinic nanorelief. The surface relief angle of MTC is proposed to classify the nanorelief angles and the sum of relief angels (θ1 and θ2) for two adjacent MTCs satisfies θ1 + θ2 = 90°. For different MTCs with the same orientation, their surface relief angles equal to each other.

Mechanisms for the development of tent-shaped and invariant-plane-strain-type surface reliefs for plates formed during diffusional phase transformations

Tent-shaped and invariant-plane-strain type surface reliefs are considered for f.c.c.→ h.c.p., f.c.c.→b.c.c. and b.c.c.→ h.c.p. diffusional phase transformations that produce plate-shaped products. Mechanisms of growth by means of mobile structural ledges with disconnection character are described. Different mechanisms are proposed to account for the two types of surface relief in cases where the transformation product is a single crystal. The predicted relief shapes and relief angles are in good agreement with experimental observations.

Machinability of ceramic and WC-Co green compacts

Machining pressed compacts of ceramic and WC-Co materials can be the most cost effective way of forming the bodies prior to sintering when the required number of pieces is small. In this study, in order to clarify the machinability for turning, the and the WC-Co green compacts unsintered were machined under different cutting conditions with various tools. Absorbing chips by vacuum hose decreases tool wear. The tool wear becomes larger in the order of the ceramic, CBN and cemented carbide tools in machining the green compacts. In machining the WC-Co green compacts, the tool wear becomes larger in the order of the ceramic, cemented carbide and CBN tools. The land of cutting edge does not affect tool wear. When machining with cemented carbide tool, the tool wear i equal cutting length is nearly identical in spite of the increase of cutting spee, and the roughness of machined surface was the best in the cutting speed of 90 m/min. The tool wear decreases with the increase of rake angle and relief angle and with the decrease of nose radius. The machined surfaces become worse with the increase of feed rate and depth of cut, and with the decrease of rake angle and relief angle. The tool wear is not affected by the feed and depth of cut.

Cutting Forces in Orthogonal Cutting of Unidirectional GFRP Composites

The results of orthogonal cutting tests carried out on unidirectional glass fiber reinforced plastic composites, using HSS tools, are presented and discussed. During the tests, performed on a milling machine at very low cutting speed to avoid thermal effects, the cutting speed was held constant and parallel to the fibre direction. Three parameters, namely the tool rake angle α, the tool relief angle γ, and the depth of cut t, were varied. According to the experimental results, the horizontal force per unit width, Fhu, undergoes a dramatic decrease, never verified for metals, with increasing α. Besides, Fhu is only negligibly affected by the relief angle, and linearly increases with t. Similarly to metals, an effect of the depth of cut on the specific energy (size effect) is found also for composites. However, the presented results indicate that the size effect can be analytically modeled in a simple way in the case of composites. The vertical force per unit width, Fvu, exhibits a marked reduction when the relief angle is increased. Fvu, is also very sensitive to the rake angle: the lower α the higher is Fvu. It is shown that this behavior probably reflects a strong influence of the rake angle on the forces developing at the flank. A linear dependence of the vertical force on the depth of cut is also demonstrated. Finally, the experimental data are utilized to obtain empirical formulae, allowing an approximate evaluation of cutting forces.

Surface relief associated with martensite and bainite in a Cu–Zn–Al alloy measured by atomic force microscopy

Atomic force microscopy was employed to quantitatively study the surface relief accompanying martensite and bainite in a Cu–Zn–Al alloy. It is demonstrated that the surface relief angle associated with martensite is 14.3°, in good agreement with the theoretical result deduced from the phenomenal theory of martensite crystallography (PTMC). However, the surface relief angle associated with bainite is 2.0°–3.2°, which disagrees with the PTMC result. This indicates that the transformation mechanism of bainite is different from that of martensite. The fine structures of the surface relief associated with martensite and bainite are also investigated. The surface relief of martensite is composed of the small parallel relief caused by small martensite plates, and that of bainite is composed of small cells induced by subunits in bainite.