Just like other consumers the world over, injection molders’ customers hate to pay for things they don’t need. That is fair enough, but problems arise when a molder believes an item is necessary and his customer disagrees.

Hot runners are one such source of strife. They add to the cost of a mold, without question. They also help save material, among other benefits, so it’s never been too hard to justify the added expense of a hot runner-equipped mold to a customer in need of millions of parts—in packaging applications, for instance. But more frequently in question is whether a hot runner makes sense for low- or mid-volume molding projects.

To support processors’ arguments in favor of hot runner use, and clearly also to help its own sales effort, hot runner manufacturer Mold-Masters (Georgetown, Ontario) has developed a Hot Runner Justification Tool, which is available on its website. Only three basic inputs are needed for the tool to yield a cost comparison trade-off for both hot runners and cold runners for a range of mold cavitations. Those in need of a more customized calculation can choose an advanced option with multiple inputs. —[email protected]