Stack Molds

When your application requires a Stack Mold, MDi can fulfill your needs.

MDi will design, build, assemble and heat test the entire system to ensure correct wiring and operation of each nozzle, manifold heater and thermocouple for a trouble-free start up and maintenance free performance. MDi offers one of the most compact stack heights available.

MDi Stack Molds are designed for friendly maintenance in that the sprue bar is completely accessible and removable from the face. This allows for ease of transporting and maneuvering. The moving side and stationary side are also wired in such a way to be split down the middle. Two electrical boxes control the heaters, one controls the moving half and the other controls the stationary side. This independence allows for friendly maintenance.

Product Features

  • Removable Sprue Bar for maintenance
  • Compact stack height
  • Independently wired plates for easy access
  • Sprue Bar fitted with Shut Off Device
  • Increased output efficiency
  • Doubling capacity
  • Water manifold, one line-in and one line-out, for quick setup (optional)


  • Stack molding requires less space
  • Save time and money by producing multiple parts simultaneously
  • Reduced waste

A Stack Mold takes advantage of Newton’s third law of motion, in that the opposite force required to inject a single face is now utilized to mold a second set of parts. A Stack Mold can use the same size of machine with only a 10-20% increase in tonnage to offset the force applied by the machine nozzle to the sprue bar.

MDi offers Stack Molds in any configuration so that the users achieve the optimum tooling solution for their application.

Hot Runner Systems made in U.S.A

MDi is a world-leading American manufacturer of Hot Runner systems and components with the capability to develop custom and innovative solutions for plastics Injection Molding. Established in 1984, MDi continues to offer experience in the design and manufacturing of complete, internally heated and balanced precision Hot Runner systems, Valve Gate systems, Sprue Bushings, Molding Machine nozzles, Filters, and MDi’s unique system products and controls. All of our components are in-house designed and manufactured in our facility at St. Charles, IL, with a focus on quality and reliability.