|
|
|
|
|
Why Hardwire Tools? One of the biggest concerns with tooling is the ability of the tool to control thermal conductivity. Exotherm, or the heat generated by curing resin systems, is controlled by dissipating the heat evenly throughout the laminate surface so as to eliminate hot spots. Conversely, heated tooling requires that the tool be heated uniformly efficiently and inexpensively, and to be able to move that heat into the surface of the laminate. While traditional FRP composite tools have served the industry well, they lack these abilities. Fiberglass is an insulator ... metal is a conductor. Hardwire "M" metallic mats (copper and carbon steel) and Hardwire unidirectional tapes provide a 1-2 punch that can be used to create composite tools that overcome the shortcomings of traditional FRP tooling. Hardwire "M" copper mat is an infusible and contourable sintered copper mat that has all of the thermal transfer capabilities that one would expect from a copper based material. Hardwire "M" carbon steel mat is also an infusible, highly contourable metallic textile fabric. This material is comprised of 3 ply's with the fibers in the outer 2 ply's running in the warp direction and a center ply that is an isotropic nonwoven layer. The completed fabric is needle punched to speed vacuum infusion processes and additionally to provide substantial "Z" directional fibers. When used in conjunction with Hardwire tapes, the Hardwire "M" copper fabrics provide enhanced thermal conductivity from the surface of the mold into the Hardwire tape layers. The Hardwire tape layers provide the reinforcement and modulus of the laminate and additionally provide thermal conductivity in the X-Y plane via their unidirectional steel cords. By interplying Hardwire "M" carbon steel material between subsequent layers of Hardwire tapes the thermal conductivity between these ply's is enhanced. Due to the increased metallic fiber content of the laminate and the commingling of the "Z" directional fibers of the Hardwire "M" materials and the steel cords of the Hardwire tapes the interlaminar shear resistance is increased dramatically as well. By utilizing Hardwire "M" metallic mat at the tool surface, thermal conductivity from the mold surface into the laminate (heated tools) and conversely from the laminate back to the mold surface (exotherm control) can be increased as well. The mold will dissipate and spread the heat from exotherm better than traditional composite molds thus minimizing the damage from "hot spots", both to the part and to the tool itself. Testing has shown that a tool made with Hardwire "M" copper mat on the surface and alternating remaining ply's of Hardwire tape and Hardwire "M" carbon steel mat can create a mold nearly as thermally conductive as steel. This combination of materials creates molds that are extremely thermally conductive yet can be molded into complex geometries via traditional composite molding processes. By placing FRP on the backside of the tool you can keep the heat in the tool due to the insulating qualities of fiberglass. Because the CTE (coefficient of thermal expansion) of steel and fiberglass are relatively close two things happen. You should be able to use the glass and Hardwire together in an unbalanced laminate (glass on back and Hardwire on face) and not realize any warping, and two, that the tool and part should expand and contract at nearly the same rate. Contact the Hardwire team for additional details, samples, and resin recommendations and to place your order today. Hardwire®
products may be purchased directly via this website or though distribution
at Composites
One. |
