TPT May 2009

T echnology U pdate

Launch of new portable hemming unit

Hemming units are essentially portable roll forming machines that form 180° hems on the edges of a flat strip of metal. Hems are primarily found on lighter gauge material to either strengthen the profile and/or improve safety, when handling. Roll-Kraft, USA, has launched a new model of hemming unit that can be designed and built to suit almost any hem requirement. Typically, the hems are formed before the metal strip is introduced into the rollforming mill or another forming process. Most hems are small (to reduce the amount of  Figure 1 – Hemming unit (driven) with integrated entry guides

material required) and can be formed in four stations. Hemming units can be configured in numerous ways. These configurations include non-driven (pull-through), driven (with overriding clutch or continuous drive), mounted directly onto the existing roll former base, freestanding (fabricated base), variable product widths for ‘quick change’ (see figure 2), single or double hem, and custom applications. Roll-Kraft hemming units are constructed using fabricated plate steel housing  Figure 2 – Adjustable width hemming unit with digital indicators

assemblies, spur gear train (see figure 3), hardened tooling spindles (overhung), adjustable top spindles with micrometer dials, built-in material entry guide (see figure 1), hardened tool steel rollers, and optional ‘quick change’ width adjustment with digital indicators (see figure 3). Another advantage of integrating a Roll- Kraft hemming unit into a rollforming system is to save money. There are numerous occasions when an existing rollforming mill does not have enough forming stations to produce a particular hemmed cross- section. Instead of purchasing a new mill or mill extension, a Roll-Kraft hemming unit  Figure 3 – Powered hemming unit with spur gears

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M ay 2009

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