Resin patterns obtained in vacuum-sealed sand moulds |
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6. A computer program for the foundry resin patterns exploitation prognoses In the manufacturing of resin patterns, the patternmakers select the components (the fillers mainly) in such proportions that would provide the prolonged exploitation of the patterns. The selection is based on characteristics taken from the company's catalogues [7] and the tentative data for the work of the resin patterns in conditions of manufacture. After the patterns are produced, the patternmakers guarantee for the wear-resistance of their products within the range of some batch of castings. The most often the given "guarantee" has a hopeful nature. For the assumption of a real guarantee could be in use the described in brief computer program for the exploitation prognoses of the foundry resin patterns RpeP (Resin-Patterns-Exploitation-Prognoses). Its main screen is presented in Fig.47.  Fig.47. RpeP - main screen At first the kind of compound and one or the other technology should be chosen. Immediately, the corresponding information appears for the initial roughness, bending strength and impact strength of the pattern. The choice follows for the permissible negative value of dimensional deviation (level of wear) in the range 0.01 - 3.20 mm. The prognosis results come into view in the right side of the same screen. They include the guaranteed number of mouldings n and the minimum number of mouldings N which the pattern with the chosen compound, technology and permissible level of wear would reach in exploitation. Moreover, the program shows the awaited roughness change and the probably level (1-5) of adherence of the molding mixtures. Below the results there are two illustrations. One of them is the scheme for the presumable pattern surface in the reached limit of wear N. From the right there is the corresponding picture of the surface structure after wear in the range of reached number of mouldings. Help section includes an information for different compound ingredients, an advisable scheme for selection of a determinative dimension, an information for the nominal dimension ranges and permissible dimensional deviations of EN 12890:2000 and GOST 11961-87, some details how the five levels of adherence of the molding mixtures to the resin patterns have been determinated (according to the green sand components, mould ramming, pattern roughness), it is shown as well that in reaching of the fourth and fifth levels, the control over the patterns have to be increased for the awaited defects in mould surface by reason of pattern. A version of RpeP contains a technological block with a complete instructions and descriptions for patternmaking in vacuum-sealed sand moulds, and with a basic technological scheme for patternmaking in plastic moulds. The program RPeP is addressed to the manufacturers of resin patterns and foundries using this kind of pattern equipment. « « « previous page next page » » » |