Research of the ways to increase the accuracy of the mirror milling machining of the waffle grids by means of the digital correction techniques

Waffle shells are the main part of the overall dry mass of the products of the aerospace industry. Cell bottom thickness and the width of the longtitudal and circular edges are the main characteristics of the waffle grid. Mechanical cutting by using of the machine tools of SVO series which perform tracking and copying of the opposite wall thus providing the stability of the bottom thickness despite of the workpiece shape errors is the most wide-spread technology of the manufacturing of the waffle grid. There are different other factors which act during such a process and lead to bottom thickness and edge width errors which brings to increase of the weight of the part, use of the additional finishing operations and rise of the defects amount during milling process. Thus it is essential to solve the problem of the increase of the machining accuracy of the cell thickness bottom, which might cause the rise of the machining performance and might help to raise the quality of waffle shells. In order to do this, authors examine in detail the waffle grid mirror milling manufacturing process. The factors which lead to the cell bottom thickness deviations were described and classified. It was analyzed and shown in the paper that deviations of the spindle axis against the surface normal affect the magnitude of cell bottom thickness errors. Authors also perform the mathematical modeling of cell bottom thickness errors because of presence of backlash in tracking system. The paper presents a detailed description of various techniques to increase the machining accuracy of the cell bottom. It was demonstrated that the most suitable is to use the combined digital compensation method by using of self-tuning system. Implementation of the solution will enhance the mass-energy properties of the aerospace products by means of decrease of the overall dry mass by attainment the higher cell bottom machining accuracy. It also will bring to raise of the quality and reliability of production by reducing the defects amount. The mirror milling machining process was considered. The factors leading to the thickness errors of the pocket bottoms were classified. Perfomed the simulation of the thickness errors genera-tion caused by the influence of the most significant factors. Techniques to increase the accuracy during machining of the pocket bottoms were analysed, provided the reason of using the combined digital correction method with self-tuning from pass to pass.