scholarly journals INVESTIGATIONS INTO THE ACCURACY OF ANGLE CALIBRATION

2012 ◽  
Vol 30 (3) ◽  
pp. 65-70 ◽  
Author(s):  
Vytautas Giniotis ◽  
Mindaugas Rybokas ◽  
Petras Petroškevičius

Technical possibilities to create equipment for the calibration of flat angles are discussed in the article. The angular standard measure, the radian, has not been realised as a standard unit until now. Nevertheless, the unit of angular measure in degrees is used as the geometric measure of length in geodesy, machine engineering and other branches of industry – by multiangular prisms – polygons with an autocollimator, rotary tables, circular scales, etc. It should be noted that these angle measures are calibrated against the upper level measures (etalons) only at the several intervals depending on the number of sides (angles) of the polygon or the other standard measure. The methods of calibration of constant angle value in full circle are used as well. At the same time geodetic instruments, rotary tables of metal cutting tools and instruments, rotary encoders have a great number of discrete values. These values between the calibrated points remain unknown during calibration. The information received during calibration relative to all the information available can be evaluated using information entropy. The equipment of calibration permitting to select significantly more information would be essential for better accuracy assurance of instruments used in machine engineering, geodesy, building structures. Theoretical and technical background for justifying and developing such equipment for angular accuracy calibration is presented here. A modern scientific and technical background validates this concept.

2017 ◽  
Vol 922 (4) ◽  
pp. 7-12 ◽  
Author(s):  
G.A. Shekhovtsov ◽  
R.P. Shekhovtsova ◽  
D.P. Ivenin ◽  
O.V. Raskatkina

The article contains the method of discrete scanning points in the vertical plane of the columns and roof trusses for the simultaneous determination of vertical columns, the distance between them in flight at their tip and deflection farms with one point standing and only one performer. The technique is based on the use of reflectorless electronic tachymeter and its SDh key. Experimental research of methods on the elements of building structures NNGASU educational housing using electronic tachymeter SET530R. Results of the experiments were monitored by a coordinate and photographic methods, as well as with the developed at the chair of Engineering Geodesy laser-mirroring device designed to measure inaccessible or hard to reach distances. Analysis methods of error theory position and the results of its comparison with other methods have shown that it provides the required accuracy, easy to perform, does not require the output of the observer on the crane path or lift to the towers, free from the multiple engagement of the bridge crane and can be successfully applied on practice.


Author(s):  
I V Shvetsov ◽  
B Ya Mokritskij ◽  
O A Malukhina ◽  
A H Rahmonov ◽  
V N Belyakov

1975 ◽  
Vol 97 (3) ◽  
pp. 1060-1066
Author(s):  
P. F. Thomason

Closed form expressions for the steady-state thermal stresses in a π/2 wedge, subject to constant-temperature heat sources on the rake and flank contact segments, are obtained from a conformal mapping solution to the steady-state heat conduction problem. It is shown, following a theorem of Muskhelishvili, that the only nonzero thermal stress in the plane-strain wedge is that acting normal to the wedge plane. The thermal stress solutions are superimposed on a previously published isothermal cutting-load solution, to give the complete thermoelastic stress distribution at the wedge surfaces. The thermoelastic stresses are then used to determine the distribution of the equivalent stress, and this gives an indication of the regions on a cutting tool which are likely to be in the plastic state. The results are discussed in relation to the problems of flank wear and rakeface crater wear in metal cutting tools.


2007 ◽  
Vol 567-568 ◽  
pp. 185-188 ◽  
Author(s):  
Miroslav Piska

Modern trends in metal cutting, high speed/feed machining, dry cutting and hard cutting set more demanding characteristics for cutting tool materials. The exposed parts of the cutting edges must be protected against the severe loading conditions and wear. The most significant coatings methods for cutting tools are PVD and CVD/MTCVD today. The choice of the right substrate or the right protective coating in the specific machining operation can have serious impact on machining productivity and economy. In many cases the deposition of the cutting tool with a hard coating increases considerably its cutting performance and tool life. The coating protects the tool against abrasion, adhesion, diffusion, formation of comb cracks and other wear phenomena.


2010 ◽  
Vol 30 (9) ◽  
pp. 910-920 ◽  
Author(s):  
F. V. Kiryukhantsev-Korneev ◽  
N. A. Shirmanov ◽  
A. N. Sheveiko ◽  
E. A. Levashov ◽  
M. I. Petrzhik ◽  
...  

Author(s):  
Mitsuru Hasegawa ◽  
Tatsuya Sugihara

Abstract In cutting of Ti-6Al-4V alloy, the cutting speed is limited since a high cutting temperature leads to severe tool wear and short tool life, resulting in poor production efficiency. On the other hand, some recent literature has reported that various beneficial effects can be provided by forming micro-textures on the tool surface in the metal cutting process. In this study, in order to achieve high-performance machining of Ti-6Al-4V, we first investigated the mechanism of the tool failure process for a cemented carbide cutting tool in high-speed turning of Ti-6Al-4V. Based on the results, cutting tools with micro textured surfaces were developed under the consideration of a cutting fluid action. A series of experiments showed that the textured rake face successfully decreases the cutting temperature, resulting in a significant suppression of both crater wear and flank wear. In addition, the temperature zone where the texture tool is effective in terms of the tool life in the Ti-6Al-4V cutting was discussed.


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