Special Feature Hot runners build on solid origins
Commercial hot runner systems have been available for over 40 years, and though the first design was patented in the US as long ago as 1940, the basic technique has not altered too much from the original. By Martin Courtney
Most hot runner systems continue to provide a conduit for a melt delivery system by extending the machine nozzle into the mould through the mould cavities whilst keeping the flow of the material hot.
Canadian pioneer Mold-Masters (acquired by Milacron for an estimated $975m in 2013) offered its first hot runner systems in 1965, in what it claims was the first embedded heater surrounding the melt channel to achieve the uniformity of temperature required to maximise part quality. But it was not until the oil crisis in the 1970s that economic conditions conspired to push technical innovation and adoption further as the rising price of raw materials forced mould and die makers to find new ways of reducing their own costs.