Tag Archives: injection mold making

When Do You Need a Hot Runner Mold?

 

Avoid Costly Runners

A hot runner mold is desirable in situations where you would have a large runner that would go to waste, thus raising the cost with excess material.  While the cost of a hot runner tool may be more than a standard cold runner mold, an economic analysis may reveal that the cost savings could pay for itself in a reasonable amount of time.  This would be especially true if the material is a costly specialty raw resin.  

Improve Geometrical Tolerances

In a hot runner mold, the material is injected directly into the cavity through a nozzle, rather than flow through the runner system.  This is done with more pressure than a cold runner tool, and can improve filling and packing into critical dimensional areas.   The pressure utilized in a hot runner tool can improve consistency in the molding process, thus improving the quality of the parts.

Improve Cycle Time

Due to the increased pressure, a hot runner tool may bring an improvement in cycle times.  All plastic processors know the value of an improved cycle time as increased efficiency equates to increased profits.   When applied to a multi-cavity tool on a high-volume project, the savings in cycle time alone could be quite significant, not to mention improving lead times with production parts.   The volume of production required from the tool is a big consideration when weighing the benefits of a hot runner tool versus a cold runner tool.

Flexible Gate Location

A hot runner tool allows for flexibility with the gate location, which can be placed in the most desirable area for consistent filling and packing.  In parts with high visibility, gate location is important to the aesthetics as well as function of the molded product.

There are two different types of gating mechanisms for hot runner tools, a thermal gate or hot-tip gating system, or a valve gate.  With a thermal gate the nozzle hardens at the tip, allowing the parts to disconnect from the nozzle prior to ejecting.

In a valve gating system, a valve slides over the nozzle tip prior to ejecting, assisting with ejection if the material does not solidify completely in the tip.  

Michiana Global Mold has knowledge and experience designing and manufacturing precision hot runner tools for customers demanding a high level of quality.  Contact Michiana Global Mold today for a free cost analysis of your next mold building project.  

Press Considerations for Injection Mold Design

 

 

When constructing plastic or rubber injection molds, in addition to the part design the molding environment that the tool will run in is of the utmost importance.  A mold designer must be aware of the injection molding process that the tool is designed for, the press it will run in including the clamping system and whether or not it is a vertical or horizontal clamping press.

 

Each injection molding press will have a particular clamping pressure that is either delivered in an electric or hydraulic system.  Some molders prefer to use all hydraulic presses, while some have a mix of hydraulic and electric, while other molders use only electric machines.  There are some benefits to both, but the mold designer must be well aware of the power and pressure utilized in the press of choice prior to designing and constructing the injection molds.

 

A mold designer, and mold builder will need to know the tonnage of the press, the clamping orientation and clamping pressure whether it is electric or hydraulic, and they will also need to know the barrel capacity of the press.  This will determine how much material will be able to flow into the mold, and based on cycle times and cavitation, will determine whether or not the tool is designed to meet projected production volume requirements.

 

Each injection molding press will also have a certain type of mounting system to secure the mold in the press.  A toe-clamping system is most common, although a skilled mold designer can adapt the tool to fit even a custom designed mounting system.  The platen must be large enough to hold the mold but it must also allow enough room to pass through the tie-bars when loading or unloading the mold.  The tie bars hold the mounting platens in place which securely hold the mold in the press, and also contain the ejection system allowing opening and closing of the mold.

 

Michiana Global Mold has vast experience designing complex, precision molds for various industries, meeting all requirements of our customers molding environment.  We are valuable addition to any supply chain, providing proven solutions with high performing quality steel molds.  Contact us today for a free design consultation, and to learn more about our discount and rebate programs.