Tolerances for angular dimensions of plastic parts, working on oil field equipment

Currently, one of the important areas for increasing the reliability, durability and efficiency of oilfield equipment is the use of plastics instead of non-ferrous and ferrous metals. The qualitative feature of plastics compared to other materials indicates that they are materials with unlimited possibilities both in terms of their inherent properties and in terms of their use as a structural material. Plastics have found extremely wide application in the oil industry. The design features of plastic parts and units of oilfield equipment and the specifics of operating conditions show that the main reasons for their short service life are not only the severe and specific requirements imposed on them, but also the limited research and development in the field of using plastics in oil engineering, in particular when choosing the optimal manufacturing technology taking into account the instability of the composition, molding material and design features of the product when calculating the design elements. The article examines the tolerances for the angular dimensions of plastic parts operating on oilfield equipment. An analysis of a large number of factory drawings of plastic parts operating on oilfield equipment has shown that tolerances for angular dimensions are set very arbitrarily, design requirements are not consistent with the capabilities of the technology and are often not justified. The explanation for this situation should be sought precisely in the variety and insufficient completeness of recommendations for the selection of tolerances for the angular dimensions of plastic parts, in the absence of uniform rational standards of accuracy for these dimensions. Indeed, all available data does not differentiate between different grades of plastics, which have different precision characteristics and different methods of processing plastics into parts.