Any time the process window can be opened to provide more optimal molding conditions, molders love it. With its new HPgate, hot-runner specialist HRSflow (San Polo di Piave, Italy) introduces an innovative, quality-enhancing, cost-saving valve gate technology for the manufacture of high-quality parts without flash. Unlike conventional products, the gate is machined on a hardened metal insert produced by HRSflow. This insert is simply screwed into the mold, so it’s easy to replace in the event of wear.
|The new HPgate concept from HRSflow (right) introduces a hard metal insert screwed into the mold, in which a conical cylindrical gate is machined. If it becomes worn, the closure can be easily restored without performing conventional cost-intensive work on the mold.|
HPgate rids the moldmaker of the time-consuming and complex task of machining standard cylindrical gates. In fact, with the gate geometry already machined on the insert, HPgate eliminates the difficulties associated with cylindrical configurations, including narrow tolerances, large and variable depths and coaxiality between the needle and gate. Equally beneficial for the moldmaker is the hardness of the insert, meaning that a softer steel could also be chosen for the mold plates.
Another advantage comes from the special needle geometry: The conical contact surface allows better thermal control of the needle temperature, while the precisely aligned cylindrical needle closure creates a seal. With conventional conical configurations, there tends to be formation of a plastic layer at the gating point when the valve closes. When the mold opens, this layer is torn from the part and could lead to flash formation. In order to achieve adequate detachment and avoid flash, a fine adjustment of process conditions typically is required. By eliminating this layer, HPgate reduces the time needed to optimize the respective process parameters. Targeted molding quality is attained much faster, which is basically equivalent to enlarging the process window.
Even better gate quality can be obtained by combining HPgate technology with HRSflow's FLEXflow technology. Here, the needle position can be precisely controlled, thereby further reducing the influence of process conditions. The result is high-quality reproducible parts with optimal gate aesthetics.
HRSflow is a division of INglass S.p.A. and specializes in the development and production of innovative hot-runner systems for the injection molding industry. The group of companies has more than 1,100 employees and is present in all the major global markets. HRSflow produces hot-runner systems at its European headquarters in San Polo di Piave, Italy; in Asia at its plant in Hangzhou, China; and at its U.S. facility in Byron Center near Grand Rapids, MI.