Core boxes lined with PTFE for hot-box process - gives easy ejection of cores by preventing sand baking onto core box walls

摘要

The internal walls of both halves of the core-box are lined with a plastic, pref. PTFE. To obtain good adhesion, the surfaces to be coated can first be roughened and, if necessary, a suitable intermediate layer can be applied; the thickness of the PTFE coating is e.g. 30 microns. By stopping the sand baking onto the walls, the prodn. of faulty cores and/or the necessity for repairing damaged core-surfaces is avoided.