A Feedback Vibration Controller for Circular Saws

1979 ◽  
Vol 101 (1) ◽  
pp. 44-49 ◽  
Author(s):  
R. W. Ellis ◽  
C. D. Mote
Keyword(s):  
Transverse Vibration ◽  
Laboratory Tests ◽  
Cutting Performance ◽  
Laboratory Findings ◽  
Circular Saw ◽  
Theoretical Predictions ◽  
Control Production ◽  
Proportional Derivative Controller ◽  
Circular Saws ◽  
Stiffness And Damping

Transverse vibration of circular saws is detrimental to their cutting performance. A feedback controller which increases the transverse stiffness and damping of a circular saw is analyzed, designed and tested. The proportional-derivative controller suppresses saw vibration with electromagnetically induced forces. Laboratory tests confirm theoretical predictions and demonstrate stiffness and damping increases greater than 400 percent with control. Production tests on the controller support the laboratory findings.

Circular Saw Vibration Control by Induction of Thermal Membrane Stresses

1981 ◽  
Vol 103 (1) ◽  
pp. 81-89 ◽  
Author(s):  
C. D. Mote ◽  
G. S. Schajer ◽  
S. Holo̸yen
Keyword(s):  
Vibration Control ◽  
Induction Heating ◽  
Transverse Vibration ◽  
Critical Speed ◽  
Dimensional Accuracy ◽  
Optimal Temperature ◽  
Blade Vibration ◽  
Circular Saw ◽  
Speed Stability ◽  
Circular Saws

Circular saw transverse vibration and product dimensional accuracy were measured during a series of production experiments in which sawblade vibration was controlled by the deliberate introduction of thermal membrane stresses. Induction heating near the saw collar was used to control the temperature difference between two concentric annular zones on the sawblade surface. Optimal temperature conditions were predicted using the critical speed stability theory for symmetrical circular saws and these predictions were verified through production experiments. Feedback control of sawblade temperature was successfully demonstrated in production as a means of reducing blade vibration and improving dimensional accuracy.

Experimental and Theoretical Rotordynamic Characteristics of a Hybrid Journal Bearing

1997 ◽  
Vol 119 (1) ◽  
pp. 132-141 ◽  
Author(s):  
J. T. Sawicki ◽  
R. J. Capaldi ◽  
M. L. Adams
Keyword(s):  
Journal Bearing ◽  
Operating Conditions ◽  
Dynamic Force ◽  
Test Results ◽  
Force Measurements ◽  
Lubrication Equation ◽  
Load Cells ◽  
Theoretical Predictions ◽  
Stiffness And Damping

This paper describes an experimental and theoretical investigation of a four-pocket, oil-fed, orifice-compensated hydrostatic bearing including the hybrid effects of journal rotation. The test apparatus incorporates a double-spool-shaft spindle which permits independent control over the journal spin speed and the frequency of an adjustable-magnitude circular orbit, for both forward and backward whirling. This configuration yields data that enables determination of the full linear anisotropic rotordynamic model. The dynamic force measurements were made simultaneously with two independent systems, one with piezoelectric load cells and the other with strain gage load cells. Theoretical predictions are made for the same configuration and operating conditions as the test matrix using a finite-difference solver of Reynolds lubrication equation. The computational results agree well with test results, theoretical predictions of stiffness and damping coefficients are typically within thirty percent of the experimental results.

The Mechanical Analysis of the Composite Reinforced Circular Saw Blade

2011 ◽  
Vol 228-229 ◽  
pp. 484-489
Author(s):  
Xiao Ling Wang ◽  
Zhong Jun Yin ◽  
Chao Zhang
Keyword(s):  
Volume Fraction ◽  
Mechanical Analysis ◽  
Loading Conditions ◽  
Circular Saw ◽  
Model And Simulation ◽  
Circular Saw Blade ◽  
Saw Blade ◽  
Reinforcement Model ◽  
Circular Saws ◽  
Composite Reinforcement

Thinner saw blades cannot resist large lateral cutting forces due to their lower stiffness. In this paper we propose a composite reinforcement method to improve the mechanical properties of circular saw blades. We analyze and simulate the stress and strain fields of our proposed reinforced circular saws by Finite element method. Our analytical results contain not only influences of reinforcing parameters but also loading conditions on the lateral stiffness and the natural frequency of composite saw blades. Here the reinforcing parameters include: 1) the reinforcement location on circular saw blades, 2) the volume fraction of the reinforcements, 3) the number of the reinforcements; and loading conditions include: 1) the cutting force, 2) the rotational speed. Our composite reinforcement model and simulation results can contribute to a better design of circular saw blades.

scholarly journals Analysis a cutting edge geometry influence on circular saw teeth at the process of crosscutting wood

2009 ◽  
Vol 57 (5) ◽  
pp. 177-182 ◽  
Author(s):  
Ján Kováč ◽  
Milan Mikleš
Keyword(s):  
Cutting Tools ◽  
Measurement Procedure ◽  
Cutting Edge ◽  
Production Costs ◽  
Cutting Process ◽  
Detailed Measurement ◽  
Edge Geometry ◽  
Circular Saw ◽  
Measuring Devices ◽  
Circular Saws

Nowadays, the wood cutting process looks like a technological scheme consisting of several connected and relatively inseparable parts. The crosscutting wood is the most widespread in the process of fo­rest exploitation; it is used at tree exploitation, shortening stems and assortment production. The article deals with the influence of the cutting edge geometry of circular saws on the torque and also on the cutting performance at the crosscutting wood therefore there is the influence on the whole cutting process. In the article there is described detailed measurement procedure, used measuring devices and the process of results analysis. Knowledge of wood crosscutting process and choice of suitable cutting conditions and cutting tools will contribute to decrease production costs and energy saving.

Detecting diagnostic error in psychiatry

Diagnosis ◽  
2014 ◽  
Vol 1 (1) ◽  
pp. 75-78 ◽  
Author(s):  
James Phillips
Keyword(s):  
Error Detection ◽  
Gold Standard ◽  
Laboratory Tests ◽  
General Medicine ◽  
Diagnostic Error ◽  
Diagnostic Process ◽  
Psychiatric Diagnoses ◽  
Tissue Analysis ◽  
Laboratory Findings ◽  
Diagnostic Categories

AbstractThe question of diagnostic error in psychiatry involves two intertwined issues, diagnosis and error detection. You cannot detect diagnostic error unless you have a reliable, valid method of making diagnoses. Since the diagnostic process is less certain in psychiatry than in general medicine, that will make the detection of error less confidant. Psychiatric diagnostic categories are developed without laboratory tests and other biomarkers. These limitations dramatically weaken the validity of psychiatric diagnoses and render error detection an uncertain undertaking, with go gold standard such as laboratory findings and tissue analysis, as in most of general medicine. With these limitations in mind, I review the methods that are available for error detection in psychiatry.

Experiments on the Active Control of Circular Disk Vibration

2001 ◽  
Author(s):  
J. B. Qiu ◽  
X. Q. Huang ◽  
D. Q. Wang
Keyword(s):  
Control System ◽  
Active Control ◽  
Transverse Vibration ◽  
Circular Disk ◽  
Experimental Results ◽  
Electromagnetic Actuator ◽  
Computer Memory ◽  
Circular Saw ◽  
Mechanical Element

Abstract Circular disk is a basic mechanical element, which is used widely in industry such as turbine machine, circular saw, and computer memory. Considering the requirements for the actuator to control the transverse vibration of circular disk, the non-contact electromagnetic actuator which can produce large actuating force is used, and a whole set of control system that is composed of analog components is built. The good experimental results are obtained by using the control system to control the transverse vibration of circular disk.

The fate of detergent surfactants in sewer systems

1995 ◽  
Vol 31 (7) ◽  
pp. 321-328 ◽  
Author(s):  
E. Matthijs ◽  
G. Debaere ◽  
N. Itrich ◽  
P. Masscheleyn ◽  
A. Rottiers ◽  
...  
Keyword(s):  
Fatty Alcohol ◽  
Half Life ◽  
Laboratory Tests ◽  
Field Experiments ◽  
Sewage Treatment ◽  
Field Studies ◽  
Municipal Sewage ◽  
Alcohol Ethoxylate ◽  
Rapid Reduction ◽  
Laboratory Findings

The fate of detergent surfactants in the sewer can be studied both in laboratory tests and in field experiments. The laboratory studies can be used to determine the rate of disappearance of a test molecule as a function of residence time and estimate its half-life in a given habitat. In addition, important information can be obtained on the mechanism of degradation. Field studies can determine the actual environmental concentrations of surfactants in raw sewage which can then be compared with the expected concentration based on consumption volumes. The difference between the measured and predicted concentration provides an estimate for the disappearance of the test chemical during its travel in the sewer and confirms the results of the laboratory tests. This paper focuses on the fate of a number of important representative anionic, nonionic and cationic surfactants, in the sewer. The results of laboratory die-away studies showed that, in general, the half-life for disappearance in the sewer was in the order of hours for Fatty Alcohol Ethoxylate (AE), Fatty Alcohol Ethoxy Sulphate (AES) and Di-Ethyl-Ester Di-methyl-Ammonium Chloride (DEEDMAC). These laboratory findings for AES were confirmed by monitoring actual raw sewage reaching municipal sewage treatment plants. In addition, a field study demonstrated that the concentration of glucose amides (GA) is considerably reduced during its travel in the sewer. These complementary laboratory and field studies provide key information for the safety assessment of surfactants. They demonstrate that the concentration of surfactants can be significantly reduced in the sewer resulting in a rapid reduction of the environmental loading, which is particularly important in environmental situations where inadequate or no sewage treatment exists.

Multivariate interpretation of laboratory tests used in monitoring patients

1990 ◽  
Vol 36 (5) ◽  
pp. 748-751 ◽  
Author(s):  
H B Slotnick ◽  
P Etzell
Keyword(s):  
Small Groups ◽  
False Positive ◽  
Laboratory Tests ◽  
False Negative ◽  
Test Results ◽  
Laboratory Findings ◽  
Bonferroni Inequality ◽  
The Impact

Abstract This study demonstrates an approach to the problem of minimizing false-negative and false-positive laboratory findings. In this approach, we consider the fact that results of laboratory tests are correlated, utilize within-person test results to interpret current results, and minimize the impact of multivariate conservatism by examining test results in small groups. The procedure requires panels of tests to be divided into related subpanels, testing each subpanel independently, and using the Bonferroni inequality to determine whether any of the observed values for a given subpanel is "out-of-range." The procedure is demonstrated, and its limitations are observed and discussed.

Influence of Coupled Asymmetric Bearings on the Motion of a Massive Flexible Rotor

1967 ◽  
Vol 182 (1) ◽  
pp. 255-280 ◽  
Author(s):  
P. G. Morton
Keyword(s):  
Equations Of Motion ◽  
Arbitrary Mass ◽  
Dynamical Characteristics ◽  
Theoretical Predictions ◽  
Method Of Solution ◽  
Rotating Shafts ◽  
Stiffness And Damping ◽  
Oil Films ◽  
Stiffness Distribution ◽  
Model Rotor

The rotors of a majority of rotating machines are supported upon bearings whose flexibility has a significant effect on the dynamics of the system. Supports incorporating hydrodynamically maintained oil films in particular, in addition to possessing different stiffness and damping in mutually perpendicular planes, exhibit non-reciprocal coupling between motions in these planes. The author develops the equations of motion for a rotor-bearing system of this type, and describes how both the response to an out-of-balance forcing and the unstable behaviour of such a system may be predicted by evaluating separately the dynamical characteristics of the rotor and the bearings. The method is applicable to systems in which the rotor is axisymmetric and has an arbitrary mass and stiffness distribution symmetrically disposed about its centre of span. Some new aspects of the resonant and unstable behaviour of rotating shafts are brought out due to the nature of the method of solution. Theoretical predictions are compared and agree very well with the results of tests on a 1380 lb model rotor supported on two 4 in diameter cylindrical journal bearings.

Focus on Carbide-Tipped Circular Saws when Cutting Stainless Steel and Special Alloys

2015 ◽  
Vol 1114 ◽  
pp. 13-21 ◽  
Author(s):  
Mario Rosso ◽  
Ildiko Peter ◽  
Federico Gobber
Keyword(s):  
Grain Size ◽  
Wear Resistance ◽  
Tungsten Carbide ◽  
Cobalt Content ◽  
Coarse Grained ◽  
Cemented Carbides ◽  
Grinding Wheel ◽  
Large Power ◽  
Circular Saw ◽  
Circular Saws

Circular saw blades are used exclusively for cut-off work, ranging from small manual feed operations, up to very large power fed saws commonly used for sectioning stock as it comes from a rolling mill or other manufacturing processes for long products. The teeth profile, as well as the tooth configuration are of fundamental importance for the blade performances; through a combination of blade rigidity and grinding wheel condition a good quality surface finish is attained for tools of commercial standard. The materials used for the production of circular saw blades are ranging from high speed steel to cemented carbides. In particular, cemented carbides, being characterized by high hardness and strength, are used in applications where materials with high wear resistance and toughness are required. The main constituents of cemented carbides are tungsten carbide and cobalt. Tungsten carbide imparts the alloys the necessary strength and wear resistance, whereas cobalt contributes to the toughness and ductility of the alloys. The WC-Co alloys are tailored for specific applications by the proper choice of tungsten carbide grain size and the cobalt content. The grain size of the tungsten carbide in WC-Co varies from about 40 µm to around 0.3 µm, the cobalt content from 3 to 30 wt%. The coarse grained hardmetals are mainly used in mining applications, the smallest grain size being about 3 µm and the minimum cobalt content 6 wt%. The grain size of tungsten carbide in the metal cutting industry, as well as for universal applications lies in the range of 1-2 µm. However, with the advent of near net shape manufacturing and thin walled components, the use of submicron carbide is growing, since their high compressive strength and abrasive wear resistance can be used to produce tools with a sharp cutting edge and a large positive rake angle.In this invited paper, a general overview on the actual trends in the choice of the best material when cutting special alloys will be presented and discussed. Based on the recent and past literature some examples of their up-to-date application, such as circular saws used to cut stainless steels and some high strength alloys, are talk over.

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