90-degree thermal strut in a single step
“Linetec is one of very few companies in North America to provide 90-degree thermal strip with a single pass using Technoform Bautec’s polyamide insulating strips and Müller Technologies AG’s knurling equipment to install the strip simultaneously on two planes of material,” explains Bart Hensley, sales engineer at Technoform Bautec.
The need for direct access from both sides has always been a design limitation of strip systems. This new capability frees up window and curtainwall designers to detail changes in place more efficiently, using a single assembly, rather than multiple pieces – without compromising energy efficiency or condensation resistance.
When installing thermal strip, Linetec follows the requirements of AAMA QAG-2-12, “Voluntary Quality Assurance Processing Guide for Polyamide Thermal Barriers.” First, the inside and outside aluminum profiles are finished in anodize, liquid paint or powder coating. Different colors and finishes may be used on each profile as the aluminum is extruded independently with a cavity that will receive the strip.
During the assembly process, knurling produces “teeth” in the aluminum pocket that “bite” into the strip and ensures appropriate shear strength of the composite profile. As material passes through the knurler, the strip is inserted into the extrusion cavity. The crimping process mechanically locks the aluminum and strip, forming the bond between the two extrusions and the strip.
Traditional 90-degree thermal strip installation was time-consuming where each piece is knurled up to three times before crimping and shear testing. This amount of handling increases the potential for marring and damage to the finished material. This new 90-degree thermal strip process employed by Linetec’s reduces the knurling to one step. This not only saves time and labor, but also minimizes inconsistencies and waste, holds customer-specified tolerances for U-Factor and shear testing, and delivers a high-quality finished product.