Resin patterns obtained in vacuum-sealed sand moulds

7. Basic results of the research 1. The original technological and constructional schemes for resin patternmaking in vacuum-sealed sand moulds are presented. All they are under the protection of Bulgarian Patents and Author's Certificates. A part of shown versions are put into practice. 2. It is established the influence of the negative mould - vacuum-sealed or plastic, over the forming of surface layer of the resin patterns, at that the values of macroscopic angle of wetting Q for the contact area mould-resin are found, and the regression equations for Q = f (Time) depending on the type of the mould are worked out. 3. It is formed a new experimental way for the investigation of the roughness of the patterns obtained in vacuum-sealed sand moulds, at that it is fixed the influence of the grain size of the sand and the vacuum values on the pattern roughness through the corresponding regression equations. 4. It is founded an original test set for the research of the accuracy of the vacuum-sealed sand moulds, and as a result of that research the regression equations are worked out for the change of the mould dimensions depending on the vacuum and the duration of vibration. 5. It is built up a simple and unutilized till now test set for the comparative investigation of wear through the rotation in silica sand of a new shaped sample made of different compounds. 6. It is originated a new method for the determination of the initiated for the first time in the patternmaking limits: - a guaranteed wear-resistance (limit n), which does not require specifying of the composition of the moulding sands or the   moulding method, and which serves for the assumption of a real guarantee from the patternmakers for their patterns in the   exploitation, and - a minimal wear-resistance (limit N), which relates to the green moulding sands as the moulding method is of no importance, and   which assists the moulders in the determination of the time when the control over the patterns has to be increased due to   the expectations for an eventual their repair or change. Along with that new method, the specific data are given for the limits n and N for a variety of compounds, for which regression equations are worked out. The equations permit the inserting of the experimental data into the permissible dimensional deviations of dimension ranges of international / national standards or customer requirements, which would discontinued the existing in some publications and standards a determination of the patterns life time approximately and in so wide limits. 7. On the basis of routine structural and quantitative analyses, for the first time the parameters of the external layers of the patterns made in vacuum-sealed or plastic moulds and with use of three types of fillers to the resin are defined. 8. It is worked out for the first time a visualization of the process of the resin patterns wear along with the corresponding description of the basic situations in the wear. 9. It is built up an algorithm along with the synchronization with the different parameters for the development of a computer program for the foundry resin patterns exploitation prognoses (in project). In conclusion, it is assumed that this research will be in the interest of the patternmakers and foundries which use resin pattern equipment. « « « previous page             content » » »