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Valve Gating
Valve gate hot runner systems control the flow of plastic into the mold cavity using mechanical shut-off pins that allow the hot runner nozzle to open and close at the tip. The ability to accurately control the flow of material through the gates produces better plastic parts and faster cycle times. Valve gating is also an essential tool for automated production because it enables faster mold start-ups, a wider processing window, and eliminates the stringing and drooling of melt at the gate.
Rheo-Pro® valve gate hot runners offer a wide range of solutions for injection molded plastic parts that require superior gate and surface quality and fast cycle times. Whether molding small, high-cavity medical parts or large cascade injected components for the automotive industry, valve gating can dramatically improve the performance and efficiency of injection molding projects. MHS hot runner systems are engineered for superior precision and reliability.
 
MHS offers a wide range of innovative, high performance valve gate solutions, such as new Rheo-Pro® Black Box™ valve gate actuators (left) and multi-tip valve gate nozzles (right)
Precision Performance
It is critical that valve gated hot runners are built using only highly wear resistant materials that can perform under the extreme conditions in which they operate. Heat, pressure and corrosion will quickly deteriorate components that do not adhere to strict tolerances and quality standards. That is why every Rheo-Pro® hot runner system is fully backed by a comprehensive warranty.
No More Cooling Required
Cooling-free Black Box™ and iVG™ hot runners represent a new generation of valve gate systems that does not require maintenance during the life of the mold. These systems eliminate all quality issues related to cooling water such as corrosion and contamination. Less plumbing also simplifies the design and assembly of the mold. New cooling-free technology can benefit all valve gate applications, including high temperature plastics such as PEEK, LCP, PSU, PEI, and PPS, known for their special properties. Processing these materials requires high melt temperatures of up to 450°C in the hot runner and mold temperatures of over 200°C. Black Box™ and iVG™ hot runner systems deliver uninterrupted performance under extreme conditions without cooling or wear. The result is a significant increase in reliability and mold uptime.
Black Box™ and iVG™ valve gate actuators operate directly inside the mold without cylinder cooling or wear
 Black Box™ Valve Gate Actuators
The new Rheo-Pro® Black Box™ valve gate cylinder operates without elastomeric seals or lubricants, delivering continuous operation at temperatures of 450°C without cooling or maintenance. The new technology outperforms electric, hydraulic, and conventional pneumatic valve gate hot runners in a wide range of applications.
Rheo-Pro® Black Box™ valve gate actuators require no cooling and operate maintenance-free in temperatures up to 450°C
No More O-Rings
Imagine a valve gate hot runner system that operates without a single o-ring seal and without actuator cooling (and also without large, external electric actuators, belts or plates, components that can't take the heat inside the mold). Think of the time and cost savings on preventative maintenance, or worse, emergency repairs and mold downtime. Also consider the potential of eliminating all issues related to cooling water like corrosion and mineral deposition, by doing away with cooling lines all together. Now think of all the plumbing that this represents for each drop. Finally, consider the valuable time spent waiting for the hot runner to cool before taking the mold off the machine. All of these are issues of the past with new cooling-free valve gate solutions like the Rheo-Pro® iVG™ and the Black Box™. The future of valve gating is finally here.
The o-ring seal represents the Achilles heel of every valve gate hot runner because no matter how advanced the elastomer, it will always require cylinder cooling and eventually break down and need to be replaced
Pre-Guided Valve Pins
During the closing movement, the valve pin is first precentered
by an angled guide area and then positioned
perfectly in the gate orifice by means of a cylindrical
guide. Every Rheo-Pro® hot runner nozzle and valve pin is designed and manufactured to provide
continuous performance, superior gate quality, and a long component lifetime.
 Gate detail (gate closed)
 Gate detail (gate open)
Accurate Sequence Control
MHS offers a flexible and user friendly program of high performance control solutions for all sequential fill plastic parts. From mold mounted air actuation units to wireless, browser based controls, Rheo-Pro® CV valve gate sequence controllers ensure consistent results for a wide range of injection molding projects.
Rheo-Pro®
CV series valve gate controllers offer powerful, user friendly solutions for applications with 4 to 300 control zones
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Advantages of Valve Gating |
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No drooling or stringing of the gate |
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Improved processing window |
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Shorter cycle times, increased productivity |
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Better plastic part surface and gate quality |
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Accurate control of injection timing and melt distribution |
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Optimized cavity venting and weld line positioning |
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Faster mold start-up |
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Improved automated molding cells |
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Ideal for thin-wall parts, foam and gas assist injection |
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The Advantages of Air
Valve gates can be actuated with pneumatic air pressure, hydraulic oil pressure or electric components. The most reliable and practical valve gate actuation is air operated because it is a clean, low cost and universally available medium. Air offers an easy to connect and accurate control circuit with maximum flexibility for opening and closing an unlimited number of valve gate nozzles. Rheo-Pro® valve gate actuators are virtually maintenance free and perform under the most demanding operating conditions.
Rheo-Pro® adjustable, pre-guided valve pins can be lengthened or shortened directly from the top of the cylinder using only a conventional screwdriver, pictured here with air supply through top clamp plate
iVG™ Internal Valve Gate
The Rheo-Pro® iVG™ is an internally air actuated valve gate system with no external cyclinder, no o-ring seals, no lubricant, and no cylinder cooling. It represents the latest and most innovative valve gate technology in the industry and is ideal for ultra compact mold designs. The iVG™ performs well under the most demanding processing conditions. Unlike electric valve gates and conventional pneumatic cylinders, that can fail in extremely hot operating environments, the internal valve gate performs at temperatures up to 400°C.
Rheo-Pro® iVG™ nozzles come in a number of compact sizes for a wide range of applications and part weights
Valve Gate Stack Molds
Compared to conventional single-face molds, stack molds can virtually double the output of an injection molding machine by distributing the plastic melt into two or more separate mold parting surfaces.
iVG™ internal valve gate nozzles for back-to-back stack mold applications are clean, compact, and low maintenance
Multi-Tip Valve Gates
The Rheo-Pro® M05VG is a valve gate version of the standard M05 multi-tip nozzle. It can direct valve gate micro parts with a weight of less than 5 mg. It delivers clean gate marks of 0.7 mm - 1.0 mm diameter with zero gate vestige.
The M05VG is the only hot runner nozzle in the world that features 4 and 6 tips in a single, compact valve gate nozzle
M3
Our all new electro-pneumatic micro-injection molding machines offer unparalleled performance in an extremely compact, user friendly package. The M3 series features our patented ISOKOR™ technology, specifically designed to address the unique challenges of molding small, direct-gated plastic parts. From prototype, to low volume, to mass production - M3 molding cells deliver superior part quality, speed, and flexibility.
M3 injection molding machines offer a fast, seamless transition from protoype molding to high volume production of small to micro-sized plastic parts, using low cost cavity inserts
The new M3 series changes the rules of micro injection molding. It is the only platform that can produce small plastic parts on this scale without the use of cold runners and sub-runners. A single grain of plastic granulate can mold multiple parts. |
