Refrac Systems (Chandler, AZ), a specialist in vacuum metallurgy and diffusion bonding, is currently developing what is believed to be the world’s first gas fan quench cooled vacuum hot press (GFQVHP) at its Die-Bond LLC location in Chandler, Arizona. The new furnace design, will allow for the direct diffusion bonding of large plastic injection molds that contain conformal cooling channels, and will be able to ‘quench harden’ even 3,500-lb molds directly after the diffusion bonding process.
Conformal cooling technology is experiencing greater demand as the complexity of molded parts increases involving complex geometries, thin-to-thick wall sections and other design elements that create cooling challenges. While there are several ways to create conformal cooling channels, the industrial laminate ‘Diffusion Bonding’ process has become one of the new technologies that provide many added benefits over other types of cooling channels including conventional vacuum brazing and 3D metal printing.
Diffusion bonding can be performed by several different processes including Solid State Diffusion Bonding, where two or more matting parting parts are joined together without the use of any other interface material or treatment; Activated Diffusion Bonding in which the surfaces to be bonded are coated with a second “B” material, typically having a smaller atomic diameter and higher vapor pressure than the parent materials; and Liquid Interface Diffusion (LID) Bonding which places a second “B” material at the bond interface with the intention that it will go liquid during the bonding operation, much like a traditional brazing operation but where the bond interface is much thinner and has many other significant metallurgical differences.
The design of this new furnace will accommodate the bonding and direct hardening of conformally-cooled injection molds up to 36” wide x 31.5” tall x 50” long, weighing up to 3,500 lbs. (and this mass also allows for the additional 1,500 lbs. of required furnace tooling press platens that keep everything flat). It has 5 inch diameter “hot rams” with a 36” stroke length to make for easy loading of injection molds with varying height. The 5,000 lb system total load rating is based on using a 80 helium/20 argon mixture as the quench gas, and the system contains a variable frequency drive controlling a 150 HP gas fan drive motor for optimum heat rejection into a 6 million BTU/hour quench gas radiator.
The new furnace system required a large team of engineers and manufacturing specialists, funded by Refrac Systems over the course of three years, to design and produce. Refrac Systems selected Solar Manufacturing, Souderton, PA based on using a derivative of its standard 2-Bar internally quenched HFL-5748-2IQ furnace design, and Beckwood Press/Triform, Fenton, MO to construct the large 100 Ton “4-Post” hydraulic press frame with 36” of ram travel used within the system.
The new GFQVHP furnace system is expected to become operational in the first quarter of 2017, and ushers in a new era in the ease of manufacturing large plastic injection molds that contain conformally cooled water flow passages for improved mold performance including reduced cycle times and higher-quality parts. The new GFQVHP furnace system is expected to become operational in the first quarter of 2017. “The system is presently undergoing final system wiring and testing at Solar Manufacturing,” said Norman Hubele, President of Refrac Systems, “and is truly a thing of engineered beauty.”