Types Of Cuttings Research Articles

Texture prediction of milled surfaces using texture superposition method

It is difficult to evaluate surface error in three- or multi-axis milling due to the complexity of the machining geometry. This paper presents texture superposition method to evaluate the surface asperity of milled surfaces. In order to derive overall surface generation mechanism of three different types of endmill cutters including a ball endmill, a filleted (torus-shaped) endmill, and a flat endmill, a generalized cutter model is proposed by introducing the fillet radius as a variable. The surface roughness is determined by the maximum height of the effective scallop including the effects of cutter marks and conventional scallops. The runout effect caused by the geometric inaccuracy of a cutter is added to make the predicted surface closer to the actual machined surface. Through these steps, three-dimensional surface topography, according to given cutting conditions and cutter types, can be formed. From machining experiments with a three-axis machining center, validity of the developed method was verified. The method proposed in this paper can be used to improve the efficiency of three- or multi-axis milling and to generate optimal cutter paths and cutting conditions.

Electropolishing and electrobrightening of holes using different feeding electrodes

The current study discusses the surface finish of several common die materials, of which the inner holes are electropolished and electrobrightened by different types of feeding electrodes. In the experiment, two types of electrode are used with the application of continuous direct current and axial electrode feed. The controlled factors include the dimension of the electrode as well as the chemical composition and the concentration of the electrolyte. The parameters are current rating, electrode geometry, die material, electrode rotational speed and feed rate. It was found that electrobrightening after reaming requires quite a short working time, whilst the electropolishing avoids the need for reaming, thus makes the total cycle time less than electrobrightening. The electrode of boring cutter type performs better in the current investigation.

Upper limb symptoms and occupational aspects in manicurists

The purpose of this study was to identify and describe upper limb symptoms in manicurists, who also performed domestic chores, and compare them with symptoms identified in house wives. Seventy female manicurists (mean age 34 years) and seventy house wives (mean age 37 years from a similar social class as the manicurists) were interviewed by the authors. A questionnaire designed for this study provided structure to the interview. The results showed a significant difference between these groups. The manicurists were twice more prone to experience musculoskeletal symptoms than the house wives (Relative Risk=2). Some types of symptoms, such as trembling, heaviness sensation and temperature alterations, were experienced only by the manicurists. Concerning pain symptoms, the manicurists were almost three times more prone to be affected (Relative Risk=3.0). Although no statistical differences were found, the production rates for the non-symptomatic manicurists were 18% higher than for the symptomatic ones. Therefore, the results suggest the necessity of redesigning the nail clippers. Relevance to industry Different types of cutters are used in several industrial activities. Depending on their design, they can cause hand discomforts and injuries. Concurrent studies on a group of subjects exposed to such risks may lead to a better understanding of the problem, and also provide basic data for redesigning the tool.

Three-axis machining of compound surfaces using flat and filleted endmills

Flat and filleted endmills are less frequently used than ball-end cutters in 3-axis sculptured surface machining. However, they improve cutting efficiency to a great degree in some applications, such as machining smooth part surfaces or rough cutting. Presented in this paper is a method to generate cutter paths to make effective use of these cutter types. A part surface is first approximated into a triangular polyhedron. Cutter paths are then generated from the tessellated surface model. The robust method makes it possible to machine any compound sculptured surfaces regardless of their complexity. An efficient algorithm is used for calculating cutterlocation data.

Mathematical modelling using different endmills and tool placement problems for 4- and 5-axis NC complex surface machining

This paper presents the mathematical methods and algorithms to compute milling cutter placement and machined surface error analysis problems for 4- and 5-axis finished-surface machining. Different types of endmill cutters, such as the torusshaped (filleted) endmill, flat-endmill and sphere-endmill, are used for multi-axis NC machining. A generalized tool description with tool orientation variables for variant types of cutters is developed for 5-axis machining. Methods of finding an instantaneous cutting profile and the local surface geometry to analyse machined surface errors are discussed for cutter location generation. A method of deciding tool orientation to avoid rear tool collision using global geometry information is also presented. The techniques presented in this paper can be used to eliminate errors of milling tool path generation in the area of simultaneous multi-axis NC complex surface machining.

Cytotoxicity of restriction enzyme-induced dna strand breaks in radiosensitive and radioresistant human tumor cell lines

Purpose : To examine the role of sensitivity to specific types of DNA double strand breaks in human tumor cell response. Methods and Materials : The X ray-sensitive human squamous carcinoma cell line SCCfil and the X ray-resistant line SQ-20B were exposed to the restriction enzymes HaeI1I, Hinfl, Pvull, BamHI by electroporation. Cytotoxicity of these restriction endonucleases was measured by a colony formation assay. Results : Cell killing by each enzyme occurred in a concentration-dependent manner. The radiosensitive cell line was more sensitive to all four restriction enzymes than the radioresistant line, paralleling the response to ionizing radiation. However, the magnitude of the difference was smaller than for radiation. The 5-base sticky ended cutter Hinfi and 6-base blunt ended cutter Pvull were much more effective in killing cells from both lines than BamH1, a 6-base sticky ended cutter, whereas the 4-base blunt ended cutter HaeI1I was intermediate in its effectiveness. Thus, enzyme sensitivity could not be related to the type of cutter or the distance between cutting sites.

Automatic generation of the cutting-tool path for free-form surfaces

How to determine the cutter paths for free-form surfaces for NC machine tools in dealing with other type of cutters than a ball cutter is still a problem with which all researchers in this field are confronted. This paper presents a new method for overcoming the problem and gives the corresponding algorithms. Its principle in determining a cutter path is to automatically adjust the angle between the cutter axis and the free-form surface normal in the osculating plane at the cutting point in terms of the interferences and the data structure of the free-form surfaces, which is defined by any CAD system. The cutter path can be transformed into an NC code after post-processing. This new method is not only suitable for path generation for ball cutters, end cutters and other type of cutters, but also does not set any limit to the number of NC machine tool axes. Therefore, it is able to integrate any CAD system with any CAM system of free-form surfaces.

Kinetic Analysis of the Effect of Some Processing Factors on Changes in Color of Comminuted Meats during Processing

ABSTRACTChanges in the psychometric color attributes lightness (L*), hue angle (H*) and chroma (C*) of porcine lean meat batters during processing were kinetically analyzed using the empirical approach of mathematical modeling. The changes during 24 hr storage at 15°C and during heating at 40°C, 50°C, and 60°C were fitted into a model and analyzed for the effects of air pressure during chopping, cutter type and enzyme inhibitors. For changes in L* and C* at 40°C, 50°C and 60°C such kinetic analysis was not possible. Among the factors studied, “air pressure” had the greatest overall effect on color. The effect of “cutter type” was intermediate and that of “enzyme inhibitors” least. The effects found could be ascribed to changes in absorption and scatter properties of the meat batters.

A framework for prismatic part-data generation—unit-machined loop concept

Abstract A framework for prismatic part-data generation based on the concept of the unit-machined loop is proposed. The unit-machine loop is a removing volume that can be machined with a type of cutter within a type of operation. With the aid of this concept, the traditional feature representation model is discarded, and the process reasoning logic development is simplified. The factors of critical information and process knowledge of the removing volumes which influence the unit-machined loop construction are discussed. The input of the framework can be either from a two-dimensional computer-aided-design system or from a three-dimensional solid modelling system. The interface algorithms of two- and three-dimensional systems are presented. Finally, the rules for constructing the unit-machined loops are given and the concept is illustrated by the use of examples.

Delayed determination of claw laterality in lobsters following loss of target

ABSTRACT Lateralization of the paired claws into a major crusher and a minor cutter type is determined during the 4th and 5th stages of juvenile development of the lobster, Homarus americanus. Loss of both claws during this critical period delays the determination of laterality until the 6th stage when regenerate claws are present. Continued loss into the 6th stage, and beyond, however, suppresses laterality, resulting in lobsters with paired cutter claws. The critical period for determining claw laterality may therefore be extended for a brief time to cater for claw loss, which is especially common in these early juvenile stages.

接触レーザー照射用導光プローブに関する研究

To overcome disadvantages with an optical quartz fiber used in laser endoscopy, five types microprobes made of artificial sapphire (Al2O3), i. e., tip type probe, rod type probe, round tip type probe, cutter type probe and high divergent rod type probe were developed. Assessing the efficacy and safety of these probes, animal experiments were performed with the Nd-YAG laser during laparotomy. The results obtained revealed that various contact irradiations using laser microprobes were more safe and effective than the non-contact irradiations. On the basis of this results, we attempted a wide variety of clinical applications. The results suggest that the tip type probe is applicable to the treatment of protruded tumors of G. I. tract and hemostasis of G.I. bleeding, and the rod type probe and the round tip type probe are of benefit to the treatment of G.I. stensis. Furthermore, we are currently performing experimental and clinical studies on endoscopic local hyperthermia using a high divergent rod type probe and low power laser irradiation for depressed cancer.

接触型Nd-YAGレーザー照射法の組織破壊効果の基礎的検討

Basic Studies on Histoclastic Effects of Contact Type Nd-YAG Laser Irradiation. The contact type of laser irradiation therapeutics were practiced by trial use of micro-tips made of a new ceramics, as an improved application of endoscopic Nd-YAG laser therapeutics. In the case of contact irradiations under endoscopy, however, diagonal irradiations or pressed contact irradiations unintentionally happen sometimes and the safety of micro-tip operation for effluvium, which is known for historic ruptures at the contacting region, has become a subject of discussion. The extent of damages given to the tissues by 3 different types of contact type of micro-tips has been studied by applying diagonal or depressed irradiations on gastric mucosa of normal dogs under celiotomy. However, there was no significant difference in reaching depth observed between diagonal irradiation and vertical irradiation. The circular type and the cutter type of micro-tips give damages to deeper regions by pressed contact compared with the tip type. And yet it is safe, if the irradiation be made at an output of 30 Watts within 1 second. On the other hand, with the same energy (eg. 30w x 1 sec or 10w x 1 sec) there were no differences in histoclastic effects observed under the same pressure by application of the contact type of micro-tips.

Investigations Into the Clearance Geometry of End Mills

The clearance geometry of end mills has a significant influence on cutter performance. However, the degree to which variations in clearance geometry affect cutter performance has not been fully investigated. In this paper a modified definition of the clearance profile of cutting tools is applied with the objective of maintaining a constant clearance angle in the direction of material flow. Single point orthogonal milling tests were carried out with HSS blanks, each ground on a specially adapted machine tool, to a particular clearance angle in accordance with the proposed clearance profile. Comparative tests were carried out on similar cutters, albeit with flat flanks. The wear propagation was measured and the effect of clearance angle on tool life determined. The results show a definite optimum clearance angle for each of the two types of cutter.

Relative Assessment of the Dynamic Behavior and Cutting Performance of a Bonded and a Cast-Iron Horizontal Milling Machine

The dynamic behavior and the cutting performance of a horizontal milling machine, the structure of which was fabricated by bonding, are compared with those of a machine of nominally identical specification but containing cast structural components. Theoretical work predicted the chatter performance of these two machines from vibration tests, using dynamic cutting coefficients characterizing material behavior. The relative performance of the two machines is discussed with the aid of the predicted stability charts, relating to specific cutting conditions, and in a more general form, through merit charts. The stability charts were obtained also by cutting tests, carried out with a helix and a slot cutter. Correspondence between the predicted and measured stability charts was satisfactory. The chatter performance, measured in terms of the maximum stable width of cut, of the bonded machine was substantially better than that of the cast machine for both types of cutters.

Limiting conditions in a gear-shaping process

A gear-shaping process is used to cut cylindrical gears, both external and internal, with a pinion type of cutter. However, certain ‘inherent errors’ are present in the process which limit the range of the number of teeth on the gear to be cut. This paper deals with the analysis of inherent errors and suggests guidelines to avoid such errors, taking into account the effect of tip-relief angle

Study of the possibility of liquid boriding of high-speed steels

A beneficial effect of boriding may be expected only on a tool which is made of steel having a hardening temperature not above 1080°C and the technical specifications of which do not have a ground shape, e.g., dies made of steel 9KhS, taps and reamers made of steel U12, and also forged tools made of steel Kh12. For high-speed steels it is apparently only possible to subject those tool to boriding for which red hardness is not obligatory (e.g., certain components of special bearings) of fusion of the cutting edge is acceptable (e.g., certain types of cutters). For the rest of the objects made of high-speed steels boriding is unsuitable.

Experimental transformation of muscle fiber properties in lobster.

Like the chelipeds, the claw closer muscles of the adult lobster are asymmetric (dipmorphic). In the crusher claw the closer muscle is composed entirely of slow fibers, and in the cutter claw it has 65 to 75 percent fast fibers and 25 to 35 percent slow fibers. While claw placement in the adult is essentially random, it can be demonstrated in two ways that the muscle fiber properties are not genetically fixed: (i) if one claw is removed in the fourth and early fifth stages, the remaining closer muscle develops all slow muscle fibers, and (ii) if the animals are raised in smooth-bottomed containers, both claws can become cutter types, having closer muscles with more than 50 percent fast fibers. Thus, as in vertebrate skeletal muscle, the properties of lobster closer muscle fibers can be transformed by various experimental manipulations.

Tunnelling trials in chalk: Rock cutting experiments : Hignett, H J; Snowdon, R A; Temporal, J Transport and road research Lab lab report 796, 1977, 56p

This report presents the results of the performance of arrangements of drag picks and disc cutters cutting through Lower Chalk during the tunnelling trials at Chinnor, Oxfordshire. Power changes produced by varying the cutter tool type and arrangement on the machinehead were recorded and plotted against cutter tool and machine variables. The depth of cut and cutting to relief were found to be the major influences on the efficiency of cutting with both types of cutters. The implications of the trials are that cutter arrangements should be adaptable to rock conditions and that the fitting of simple intrumentation to record the power used in cutting would enable the best operational depth of cut to be identified. /Author/

Development of the Thyssen tunnel machine : Grieves, M Proc S Wales Inst Engr, V91, Nov 1976, P21–25

Reference is made to the requirements for a full face tunnel machine for operational use in the British mining industry in connection with the need to drive arterial roadways in hard rock to open up new working districts, or inter-mine connections. Negotiations within the industry and appropriate government departments is described which led to the design and construction of a prototype machine whereby data could be obtained on the operational behaviour of disc cutter types and configurations, and on the characteristics of main and ancillary bearings and environmental control techniques. Designed on a modular basis so that no single piece exceeded 1.5 M by 1.5 M by 2.35 M, and with no single piece exceeding 6 tons in weight, the installation of the machine in dawdon colliery for operational trials is discussed. The results of the operational trials over A distance of more than 1000 M are presented and discussed. On the basis of performances achieved, the author suggests that it would seem that a tunnel of some 3000 M continuous length is needed to arrive at a break-even cost per metre when compared with conventional drivages. However, a rise in wages of some 30 per cent would reduce this figure by 700 M. This comparison is based on the assumption of an average weekly advance of 15 M using conventional mechanised methods, roadheaders or mechanical loading in strata containing less than 50 per cent coal. The author considers that future developments, based on the experiences gained from driving the 3.65 M diameter tunnel in dawdon colliery, and the benefits that arise due to the earlier completion of arterial roadway systems will improve the economic justification for the use of such machines. /TRRL/

Computerized Determination and Analysis of Cost and Production Rates for Machining Operations: Part 2—Milling, Drilling, Reaming, and Tapping

In Part 1 of this two-part paper, generalized equations for cost and production were presented for five major types of machining operations: turning, milling, drilling, reaming, and tapping. In addition, detailed cost equations were presented for the turning operation for three types of lathe tools: brazed carbide tools, throwaway tools, and solid high-speed steel tools. The present paper, Part 2, presents the detailed cost and production analysis for the remaining machining operations: milling, drilling, reaming, and tapping. Individual equations are developed within each machining category for the major types of cutters and tools involved in the operation. Examples are presented illustrating the use of these equations on specific problems. In addition, equations are developed for calculating the optimum cutting speeds and tool life corresponding to minimum costs and maximum production rates assuming that the tool life-cutting speed follows the simplified Taylor equation. The optimized equations enable one to interpolate and extrapolate the cost and production determinations. Care must be exercised to check experimentally the interpolated or extrapolated values to verify the results from the calculations.