Home English | Deutsch | Español
  HomeCompanySolutionsProducts ContactSupportSearch
Caps and Closures

Over 30% Savings
New iVG™ stack mold technology allows plastic closure manufacturers to double production of valve gated parts without having to run additional or larger injection molding machines. This leap technology exploits the untapped potential of smaller, more efficient machines by adding a second parting line to the closure mold. The patented internal valve gate design of the new Rheo-Pro® iVG™ hot runner system now allows mold makers to build back-to-back "short stacks", compact enough to fit into smaller 180-300 ton machines.

A standard 48+48 iVG™ stack mold running in a small 200 ton machine can produce 96 light weight bottle closures every 3 seconds or almost 3 million parts per day, making it over 30% more cost efficient than a conventional 96 cavity single face hot runner system.

Breaking the Cycle Time Barrier
In order to lower the production cost of injection molded caps and closures, molders must increase productivity. Without investing in additional equipment, greater production output can only be achieved by reducing cycle times. However, it is impossible to cut cycle times in half on a single face mold, given the high degree of efficiency already in place. Doubling the number of parts produced by implementing a stack mold solution now makes it possible.

The costs associated with purchasing and operating additional or larger injection molding machines, molds and controllers are substantial. End users in the packaging business that rely on plastic closures for their product end up paying that additional cost with each part. The molders that produce the parts simply become less competitive with these added costs.

Rheo-Pro® iVG™ Hot Runner Systems for
Cap and Closure Molds (Standard Options)


32+32 Cavities
64 cavity turn-key hot runner stack mold system



48+48 Cavities
96 cavity turn-key hot runner stack mold system



64+64 Cavities
128 cavity turn-key hot runner stack mold system

Annual Production Rates (in Millions)

click to enlarge

Ultimate Reliability
The Rheo-Pro® iVG™ is completely front-serviceable from the mold parting line. Every component, including nozzles, valve actuators and valve pins, can be accessed quickly by simply stripping the cavity plate onto the core side while the entire mold remains inside the machine. Preventative maintenance is effectively reduced to minutes.


Over 50% Energy Savings

Rheo-Pro® internal valve gates substantially improve the carbon footprint of the molding cell through increased energy efficiency in the heating of the hot runner system as well as the operation and production of smaller molds and machines. Energy consumption alone in a 48+48 iVG™ closure stack mold results in total cost savings of over 50% compared to a single face mold with the same number of cavities. This does not include the additional savings in productivity gains and capital equipment resulting from over 30% lower production costs.

Compact Stack Molds


Learn more


Rheo-Pro® iVG™ Internal Valve Gate
High Cavitation Valve Gating
Stack Molding




  Increase production output and profitability  
  Lower capital investment: smaller injection molding machines with less tonnage required  
  Substantial energy savings improve production cost and carbon footprint  
  Internally air actuated valve gates allow for new ultra-compact stack mold designs  
  No seals, no maintenance  
  Air actuation performs well in tough, high temperature molding environments  

Single Face Molds vs Stack Molds

click to enlarge

Double Production
Stack molds that inject parts in both directions using two parting lines are used by many molders to increase the production output of their existing molding equipment. There are no new or unknown processing factors. What makes Rheo-Pro® iVG™ hot runner systems so unique is that they don't require larger injection molding machines because of their extremely compact size. They are also maintenance free by doing away with wear items such as seals and lubricants. Molds can run millions of cycles and parts continuously, without interruption.

iVG™ closure molds deliver over 30% savings in production cost for injection molders

Compared to hot tip or thermal gate systems, valve gating not only significantly increases mold uptime, it also delivers far superior part quality and consistency. This is particularly important when molding high viscosity polyolefins for stronger parts with thinner walls.

Machine requirements for a 48+48 iVG™ stack mold

No Seals, No Cooling, No Maintenance
The new Rheo-Pro® iVG™ is the world's first and only internal valve gate nozzle. It is the only pneumatic valve gate hot runner that operates entirely without elastomeric seals, lubricants, or cylinder cooling. Unlike electric actuators, the iVG™ can operate maintenance-free under extreme temperatures of up to 400°C (750°F).


Quick Finder



Hot Runners
Custom Engineered
Valve Gating

Fill, Warp, Cool, Pack
Feasibility Studies
Design Support

Molding Machines

Valve Gate Controllers
Temperature Control
Manufacturing Solutions

Solutions by Application

Heavy Shot Weight Parts

Small and Micro Parts
High Cavity Valve Gating
Sequential Valve Gating
Family Molding
Side Gating
Specialty Gating
Stack Molding
Cascade Molding
Gas Assist and Foam
Multi-Material Molding
High Temperature Materials
Insert and Overmolding
Thin Wall Molding

Solutions by User




Mold Designer

Part Designer



Solutions by Industry








Home / Products / Rheo-Pro® / iVG™ Stack Molds for Caps and Closures

Copyright © 2018 Mold Hotrunner Solutions Inc. All rights reserved.Legal | Privacy | Contact us




MHS is a global supplier of hot runner systems, injection molding machines, controllers, and engineering support for manufacturers of plastic parts.