Barrels may not immediately come to mind when processors look to enhance productivity, but Louis Berger, managing partner of InductaMetals LP, says they are critical to the equation.

InductaMetals, based in Chicago, manufactures hardened barrels for injection machines and extruders. Berger says these barrels add value to processing. Benefits include less scrap, improved yields, and reduced downtime.

“We quoted one job and estimated that the molder left 25% of his profit on the floor in the form of scrap, lost time, and other costs related to barrel performance,” Berger notes.

His viewpoint is, of course, consistent with that of other premium barrel makers. What differentiates Inducta-metals is the process it uses – open-air induction heating, what it terms “interfusion technology.” The company is unique in using this process in North America. Most competitors harden their barrels in gas-fired furnaces by such processes as spin casting.

With interfusion technology, a charge of tungsten carbide alloy is applied to a barrel near the induction coil. As the barrel passes through the coil, it heats and cools rapidly with the alloy coating. Berger says rapid heating and cooling assures an even consistency of the coating in the barrel, providing a high degree of hardening.

Berger declines to detail the process or coating thickness, but notes that barrels meet or exceed the coating thickness recommended by the Society of the Plastics Industry (0.006 in). The company recently began offering a lifetime guarantee for its top-of-the-line Ultramax barrel.

Berger doesn’t reveal pricing. “We are definitely the high end, but that goes along with the value we offer.” Dave Larson, president and owner of screw and barrel maker Westland Corp., Wichita, KS, says hardened barrels are generally 15% more costly than conventional versions. Barrels utilizing high-performance tool steels like CPM-10V, he adds, can be 30% more expensive.

In addition to Ultramax, Inducta-Metals offers the IDM barrel for fluoropolymers and the IDM-260 for high-corrosion materials.

Berger notes that his competitors use essentially the same materials in hardening their barrels, and produce quality products. But he claims that the interfusion process has some advantages over furnace techniques. One is greater coating consistency, which improves hardness. There is also potential for furnace-treated barrels to pick up iron in the closed environment, which can affect properties.

Suppliers, however, say all premium barrels deliver similar performance. While technically there may be some drawbacks to a closed-furnace process, Larson notes that barrel makers know how to compensate for them. “We see virtually no difference whatsoever in [the barrels],” he says.

Dave Hotchkiss, vp. of barrels at Bimetalix, Sullivan, WI, a division of Spirex Corp., concedes that barrels treated in a furnace can pick up iron. But this isn’t an issue with 95% of processors, and is mostly of concern to some medical processing with parts that cannot tolerate iron dilution.

Processors using InductaMetals barrels expressed satisfaction. Ken Geiger, maintenance engineer at Plastics Components, a custom molder in Germantown, WI, was emphatic, calling the barrels “the best thing that’s ever happened” at the molder.

Plastics Components bought its first InductaMetals barrel in 1995. The molder, which was running 43% glass-reinforced parts, had a worn barrel and was facing “astronomical downtime” and an anxious customer. Geiger says InductaMetals, which has a plant nearby, supplied a replacement in two days. The barrel was in use for five years and showed no wear, he claims.

The molder has 28 injection machines, ranging from 35 to 200 tons. Twenty-seven have barrels from InductaMetals. In fact, when Plastics Components buys injection machines, it does so without barrels or caps; those are sourced from InductaMetals.