FAQs about Plastic Injection Molding Temperature Control

Why control the temperature?

Many of the plastic injection molding and plastic blowmolding applications require even and precise control of temperature in order to successfully fabricate small compact–or intricate–components and finished products.    In many cases, “hot spots” or areas of localized heating from electric heating elements will not provide enough precision or even-temperature, in order to ensure that the product is of the best quality throughout.

How can you control the temperature?

There are a variety of ways that the temperature can be controlled when doing injection molding.  The best method is to utilize heat transfer fluids.  These are now the standard in the industry.  Molding machines, extruders, and reservoirs can be heated and cooled to exact temperatures via heat transfer fluids.  If they are applied at a controlled rate and circulated around the element being heated, they are very useful in precisely maintaining temperatures.

What are heat transfer fluids?

Water is the most common fluid, but sometimes it isn’t the best, especially in very high temperature situations.   There are other options (non-aqueous fluids) that are best for very high or even low temperature applications.  As well there are fluids that are better suited for either indirect heating or even for cooling (extracting heat from) the molds.

These fluids pass easily through the many small flow passage areas of molds and dies used in the plastics industry.  The fluids are not corrosive and are thermally stable as long as they are used within their applicable temperature ranges.

When should heat transfer fluids be used?

Heat transfer fluids can be used in almost every part of the manufacture of plastic materials and synthetic fibers.  When operating temperatures preclude a fluid like water, an engineered heat transfer fluid should be specified for operating temperatures ranging from -150 degrees F to 400 degrees F.  In addition, when the operating temperatures reach as high as 550 degrees F, specialized high-temperature heat transfer fluids should be used.  Various cooling and heating fluids can operate in temperatures that range from minus -40 degrees F to 550 degrees F.

What other industries besides plastics use these fluids?

Industries such as Adhesives, Textiles, Food Processing and Chemical can utilize heat transfer fluids.

For more detailed discussion about hot oils in plastics manufacturing processes, see…

Hot Oil Temperature Control in Plastics Applications; Operations and Troubleshooting