Bending the Rules of Retail Fixture Fabrication with PETG Sheet

As the number of brands competing for consumer attention at point-of-purchase reaches an all-time high, retailers are pressed to find ways to maximize the use of merchandising space and create a welcoming environment for shoppers. From magazine racks and sunglass boards to luxury jewelry and perfumery display cases, fabricators are increasingly required to handle a large number of retail fixture requests on short notice.

For these professionals, adequately responding to marketplace demands requires finding new ways to enhance production efficiencies.

Hot line bending is a process that many fabricators in the U.S. and Europe use to produce fixtures with a premium appearance. Traditionally performed with acrylic sheet, this process is becoming revamped as fabricators turn to alternative plastic materials, such as PETG sheet. Offering a variety of advantages for hot line bending, including ease of processing and excellent cost-benefit ratio, this clear, durable material can help fabricators boost production efficiencies and meet the retail industry’s needs for high-quality aesthetics and performance.

Hot Line Bending

Hot line bending is a fabrication technique for plastic sheet used to create a variety of retail fixtures, including magazine and brochure holders, shelving and high-end displays. This process is a more efficient alternative to bonding, as corners created by hot line bending plastic sheet are typically stronger than those created by attaching separate sheet pieces. This enhanced strength provides displays with more durability to withstand the harsh retail environment, decreasing the risk of breakage and extending fixture lifespan.

When performing hot line bending, the fabricator heats an area of flat plastic sheet until he can bend it without any pull back. Depending upon the size of the heated area, the sheet can be bent to a predetermined angle. To optimize results, the heated area should be at least twice the sheet’s thickness and no more than three to five times the size. Once bent, the sheet can be placed in a cooling jig to maintain the proper angle while the heated area returns to a stabilized temperature.

A semi-automatic process, hot line bending can be performed using a variety of machinery. The industry standard is a straight nickel-chromium (nichrome) resistance wire heater, which is ideal for standard-sized sheets with thicknesses of up to 6 mm. Other types of heaters can be used for projects with special requirements, including very thick or large plastic sheet pieces. Hot line bending is ideal for fixture projects requiring rounded corners, as the process does not produce sharp or jagged edges. Currently, the look produced by such rounded edges is growing in popularity among retailers, who are increasingly incorporating more modern, organic shaping and aesthetics into stores for a warm, non-industrial consumer environment.

PETG Sheet and Production Efficiencies

PETG sheet offers a number of advantages for fabricators looking to maximize the efficiency of hot line bending processes. Possessing a lower glass transition temperature (Tg) than acrylic, PETG requires less heat to reach process temperature. This property allows PETG sheet to undergo the heating and cooling stages more quickly, allowing fabricators to save energy, increase production rates and respond quickly to project requests and tight deadlines.

The material’s inherent durability also allows PETG sheet to be downgauged without sacrificing integral strength. Downgauging further reduces the heat needed to reach process temperature and bend the sheet, saving even more energy and time during the hot line bending processes. PETG sheet also does not require pre-drying, helping to amplify these savings.

Eastman Chemical Company recently produced a study on the hot line bending performance of PETG sheet compared to other plastic materials. This study used a double-sided, straight nichrome wire resistance heater powered to 200°C.

The study’s results, displayed in Chart 1, reveal that at a 5 mm thickness, acrylic sheet takes a minimum of 65 seconds to bend and 229 seconds to cool, for a total processing time of 294 seconds. Comparatively, 5 mm thick PETG sheet takes a minimum of 55 seconds to heat and 143 seconds to cool, totaling 198 seconds. Comparing these statistics, the use of PETG sheet for hot line bending represents an average increase in time efficiency of 30 percent over acrylic sheet – a marked improvement.

The study also demonstrates that this efficiency could be further enhanced when factoring in the downgauging abilities of PETG sheet. To achieve the same durability as 5 mm thick acrylic sheet, PETG sheet can be downgauged to a 3.5 mm thickness. This 28 percent material thickness reduction corresponds to a related reduction in the time and energy needed for hot line bending.

The study has further implications for fabrication efficiencies. As PETG sheet requires less heat to hot line bend, the material incorporates less strain over the course of the bending process. Combined with PETG’s inherent impact resistance, this lower strain level allows fabricators to produce more durable retail fixtures, resulting in longer fixture lifespan, minimized replacement needs due to breakage and enhanced product safety.

These advantages also hold benefits for fabricators on an environmental level. Sustainability is an increasingly important issue for retailers, and top chains like Wal-Mart and Marks & Spencer have developed and implemented programs that define specific criteria for reducing overall environmental impact throughout the supply chain. As an interconnected part of this chain, fabricators are held accountable for their use of resources. By utilizing PETG sheet for hot line bending, fabricators can save material and energy while also enhancing internal efficiencies, making their businesses friendlier for the environment as well as the bottom line.

As fabricators search for new ways to enhance hot line bending efficiencies in order to keep up with demand for quality retail fixtures, PETG sheet offers a number of benefits, including superior impact resistance, ease of processing and freedom of design. The material’s lower Tg compared to acrylic sheet also allow fabricators to save time and energy when hot line bending. These properties enable the creation of more durable, long-lasting fixtures for retailers and more efficient and sustainable production practices for fabricators.