Research On In Situ Cylindricity Measurement Of Large Shafts By V-block Method

Cylindricity is an important indicator of evaluating the surface shape errorof shafts. It affects production and quality of machined parts and theirinterchangeability by impacting nature of matching surface and rotary positioningaccuracy of accessories, Requirements for cylindrical shafts errors in machineryindustry are extremely strict.Proportion of applying large shafts to shipping, paper, power, oil and otherindustries is getting larger, and requirements for accuracy are more stringent. Due tocharacteristics of large shaft parts offline measurements are inaccessible in the actualprocessing environment and conditions, the existing cylinder measuring instrumentcannot meet the measurement requirements. Therefore, designing practical, low-cost,high-precision measuring devices for large shafts is of vital importance for China’smachinery manufacturing technology.The paper focuses on in situ cylindricity measurement methods for large shaftsand measuring device design (including hardware and software components). On theone hand, the paper theoretically analyzes current in situ cylindricity measurementmethods, stressing the characteristics and advantages of characteristics of cylindricityof V-block method. On the other hand, this paper designs a in situ measuring devicethat measures the cylindricity accurately and automatically according to the V-blockmethod. There are four points as follows:1) Comparative analysis on multi-sensor error separation method and V-blockmethodMulti-sensor error separation method and V-block method are two in situcylindricity measurement methods for large shafts applicable in practical, Byanalyzing their principles and characteristics, we can identify advantages of V-blockmethod. 2) The hardware design of the in situ cylindricity measurement device byV-block methodFurther analysis of the measurement principle of the V-block method focuses onthe defects of measuring device in V-block method designed by Poland KielceUniversity of Technology, and designs a new in situ cylindricity measurement devicefor V-block method. The new in device is more flexible with a simple structure, itcan be used simultaneously with a processing machine tool independently forsubsequent measurements.3) The software design of the in situ cylindricity measurement device by V-blockmethodSoftware design will be completed on LabVIEW2011, signal acquired by dataacquisition card on measurement device will be processed on a computer. Signalacquisition, data processing will be undertook by software, drawing the least squareserror of the measured shafts.4) Error analysis and uncertainty evaluationThis part emphasize on analysis the errors produced during the measurement byV-block method, making a separation and compensation of the main errors.Furthermore, measurement uncertainty evaluation for cylindrical will be completedon basis of uncertainty evaluation.