Magnum Venus Products (MVP), a global manufacturer of production solutions for industrial applications, is launching a new process for closed molding to increase part production by decreasing injection times.
The new technique, aptly named Fast Flow LRTM, is a blend of MVP’s Flex Molding Process and Light Resin Transfer Molding (LRTM) and uses collapsible resin channels for a faster resin flow.
Closed molding is a consistent manufacturing method that enables higher-quality parts, faster production, and reduced emissions — with less waste compared to open molding. Fiber reinforcements are laid into the base mold, the mold is closed and sealed, and the resin is injected into the closed mold cavity. Once the resin has cured, the mold is opened and the part is removed.
The process was brought about by the need to meet faster cure times for large parts using high-viscosity resins, such as for fire-retardant materials. Further trials and testing are currently underway with a large automotive manufacturer.
When using a traditional LRTM mold, the resin flow speed is dependent on the distance between the resin channel and center of the part during injection. By using the same silicone collapsible resin channels developed for the Flex Molding Process, MVP’s Fast Flow LRTM technique uses a unique channel arrangement — allowing the channels to be installed closer together to decrease the resin flow distance and speed up injection times.
In fact, this process is capable of injecting a fifty square-foot part in under four minutes using only one injection port, while also delivering a good back side surface aspect equivalent to traditional LRTM. By injecting the resin from the center to the border, the part demolds with a finished look and no visible resin channels, wasted materials or excess resin.
In the Fast Flow LRTM process, the female mold is constructed like an LRTM mold, but there are some key differences in the counter mold construction. It’s built with a silicone skin including a collapsible resin channel, then reinforced with composites. For this step of the process, MVP has developed a unique solution for bonding composites to silicone.
The rigid counter mold provides a good quality back side surface, while the silicone membrane shows the reinforcement of the produced part.