Injection mold

The use of hot runner systems is increasing due to the fact that they provide a more efficient method of molding plastic parts. The cost savings can be substantial, and the part quality is very often much better than a cold runner system.

With the increasing sophistication of today's plastic injection molds, the use of a hot runner system is becoming an industry standard. Many applications simply are not possible with the old standard sprue and cold runner system, and hot runners offer a great way to maintain uniform wall thickness and eliminate knit lines and flow lines.

What are some advantages of hot runner systems?

• Ability to minimize gate vestige
• Uniform wall thickness
• Lower cycle times
• Less waste
• Reduction or elimination of knit lines
• Great for high cavitation molding
• Often the only method for micro-molding. The center to center distance of the hot runner tips is as little as 17 mm.
• Standardization of components can mean significant savings in material and manufacturing.
• Many large molds rely exclusively on hot runners. Cold runners cannot meet the demands.

What about the maintenance of hot runner systems?

Hot runner systems require a new level of expertise on the part of the mold maker. However, this does not mean that it is overly complicated or highly specialized. A well designed system is relatively free from maintenance, once it is properly installed.

It can, and does happen, that mold makers become frustrated with hot runner systems and swear that they are too much trouble. This is usually due to the fact that the system is not properly installed or incorrectly operated in the molding process.

The leading hot runner system manufacturers have a well-trained team of specialists on hand to assist in the proper installation and operation of the systems. The time spent listening to these specialists is time well spent!

Are there different types of hot runner systems?

There are almost as many types of hot runner systems as there are suppliers! Most share some common features, however. There are sprue gated systems, valve gates, tip gates (the most common), and edge gates. Any of the major suppliers can describe in great detail why their system is the best for your application. Hot runner systems are some of the most important mold components