Research On The On-line Pneumatic Measurement And Size Control Technology In Honing Processing

Honing process is a special grinding efficient finishing method. There is a big gap between domestic honing machine and foreign honing machine both in the level of manufacturing, processing accuracy, and control mode. It is difficult to meet the actual requirements of the high dimensional accuracy, high shape precision and a high degree of automation.High machining accuracy, highly automated CNC honing machine and its key technology has become one of the important research content of the field of advanced manufacturing equipment. On-line measurement is an important part of the CNC honing machine. It is a necessary link to form closed loop control system of the honing machine and the effective means of controlling honing Holes dispersity, improving shape accuracy, and ensuring the quality of processing.In this paper, based on the elementary theory of fluid dynamics and combining the characteristics of the honing processing, a general idea of the honing machining precision control based on the on-line pneumatic measuring is proposed. This idea focused on the impact of measuring element and the actual conditions on the measurement accuracy in the honing process. On the basic of accurate measurement results, ensure the dimensional accuracy and shape accuracy by size forecast and online cylindricity monitoring to achieve the whole process measurement of honing process.The following are the main content of the research.(1) According to the basic equations of fluid dymamics theory and the special applications conditions for honing aerodynamic measurements, a curved baffle institutions measurement model is established and the concept of equivalent clearance is put forward, the mathematical model for measurement chamber backpressure in four kinds of difference conditions is established. Meanwhile, for the purpose of rising the honing processing dimensional accuracy and shape accuracy, the strategy of size control in the whole process of honing processing. These are theoretical basis for the honing of on-line measurement system for improving the precision and realize quality control in the whole honing process.(2) Using Double-feed honing head as the research object, a combination of theoretical analysis and FLUNT simulation as the method to study the structural parameters of the honing head and shield parameter measurement accuracy. The results show that the nozzle diameter and length has relations with the measurement range and precision, and the nozzle settlement should be less than0.035mm, retaining plate fillet can improve the measurement accuracy. These are theoretical basis for the optimization design in design of high precision honing tool.(3) Study the relationship between the measuring accuracy and the actual conditions of honing liquid based on simulation. First, the flow state of honing liquid in narrow annular gap is laminar flow. And the relationship between the viscosity and temperature of the honing liquid and the magnification and range of the measurement is discussed. The optimum working temperature and viscosity of the honing liquid is determined after the simulation in the different conditions. This is theoretical basis for the reasonable choice for honing liquid.(4) By systematic analyzing the factors on workpiece cylindricity, the strategy of cylindricity error control for inner honing is proposed for the first time. The three section method and slope method is used for confirming the macroscopic shape error before the honing processing. A new concept of control the shape precision is put forward based on the method of on-line cylindricity monitoring in the course of full area honing. Aiming at the requirement of high accuracy and rapid decision in the cylinder monitoring, two models of cylindricity evaluation are put forward. One is combined with the least square and dichotomy, the other is based on the projection of the least square method for roundness evaluation model. Through the simulation of the two models, the combination of the least square method and dichotomy model can be used for the cylindricity on-line monitoring in the honing process.(5) Based on the studied of time sequence model and grey model, with the honing machining dimensions for the study object, the essay verified the forecasting has higher accuracy with grey numbers of identical dimensions, and determined the optimal dimension under the condition of honing machining. The method of removal of abnormal data is used to inhibit the effect of dimension on accuracy. It has solved the problem effectively that grey forecasting model dimension is not easy to determine. A novel forecasting model SGM(a1,S0,t,1,1)is proposed, which is the combination based on gray model and time series forecasting model. And the new model can avoided single modle limitations effectively, inhibited the excessive influence of the model parameters of a single model of forecasting accuracy. The essay used honing size deviation to verify the applicability of the various forecasting models, the results show that in the essay lists various forecasting models, and the combination model has the most practical value in forecasting for honing precess.