前言 In this first update of the Handbook， the major revisions are probably those relating to running system design in wluch thevestiges of filling defects have finally been eliminated from castings.
Thus， the powerful benefits of contact pouring （in which the uruversal conical trumpet decorating all traditional filling systems is now elinunated） is finally shown to have been hugely underestimated by a number of foundries. Contact pouring has probably been the most important （and the most simple and zero-cost） initiative to revolutionise quality in castings. In addition， the adoption of various forms of tangential filter designs to gates has finally eliminated the problem of the entrainment of priming bubbles. These residual bubbles have long impaired the benefits of previous filling systems.
Gravity pouring has now advanced to the point at which I find myself having to admit that it starts to threaten my cherished and favoured casting production system： countergravity.
This is seen to be especially true for those low-pressure systems which use a refractory lining for the pressurised furnace. I only recently discovered the hugely damaging emission of bubbles from these linings during depressurisation of the furnace. This problem has clearly been a major source ofimpaired castings in the low-pressure casting industry and has hampered this industry since its beginnings.
The use of my pneumatic pump is described for the first time. It would lower costs and solve most of the problems of this industry. Thus，l continue to stand by countergravity as the optimum casting system where it can be used. My hope is that it will be teamed up with a good melting and metal handling system. Only careful foundry design will minimise bifilm populations in metals. Only when castings can be produced substantially free from bifilms will we enjoy the full benefits of castings， and metals in general， resistant to hot tearing， cracking， blisters， corrosion pitting and attack of grain boundaries， plus the benefits of extraordinary mechanical properties， potentially eliminating future failure by fracture or fatigue.
These are heady predictions. However， early results in foundries are already indicating that beautiful defect-free castings with revolutionary metallurgical benefits appear to be routinely attainable. Despite challenges from the undoubtedly unique benefits of such new processes as additive manufacture， my hope for the future for castings is based on the adoption of simple principles which could not only secure the future of our casting industry， but improve the welfare and environment of all of us whose lives depend on it.
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