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Hot Runner Systems in Injection Molding

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The use of hot runner systems in the injection molding is rising due to the fact that they provide a more perfect technique of molding plastic parts. The cost saving can be substantial, and part standard is very often much excellent than cold runner.

With the rising sophistication of today’s plastic injection molds, the use of warm runners is becoming an industry standard. Many application just are not possible with old standard sprue and chill runner system, and warm runners provide a best way to maintain uniform wall thickness and get rid of knit lines and flow lines.

What are the benefits of warm runner systems?

  • Capability to decrease gate vestige
  • Uniform wall thickness
  • Lower cycle times
  • Elimination or reduction of knit lines
  • Less waste
  • Best for high cavitation molding
  • Generally the only technique for micro-molding. The center to center distance of the warm runner tips is as little as 17mm.
  • Many big molds rely exclusively on warm runners. Cold runners cannot meet the demands.

What about the maintenance of warm runners?

Warm runners systems need a new level of skill on the part of the mold maker. Anyway, this does not mean that it is overly hard or highly specialized. A well designed system is relatively free from maintenance, once it is rightly installed.

mold maker
mold maker

It can, and does happen, that mold makers become upset with these systems and swear that they are too much issue. This is generally due to the fact that the system is not rightly installed or badly operated in the molding process.

The leading system producers have a well-trained team of experts on hand to help in the right installation and operation of the system. The time spent listening to these experts is time well spent!

Long term advantages

Even though there is a primary investment with hot runner systems. It is simple to justify the long-term advantages. Without rising the complexity of the design of the mold, a hot runner equipped mold can significantly decrease costs. Because the hot runner is designed and produced independently, yet concurrently, the lead times are not affected.

Mold maker should forever advise techniques for his customers to decrease molding costs and rise the output of the mold. Being knowledgeable with different runner system is a best way to demonstrate an active role in supporting the molders bottom line. This in turn makes the likelihood of increased business even bigger for the mold maker.

Plastic Injection Molds

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Plastic Injection Molds

If you demand long-life plastic injection molds, it is insufficient if you only requires good mould from mold supplier; the life of the mold have great relationship with normal operation and maintenance, so a mature molding company usually have plastic mold engineer, who will responsible for mould repairing and maintenance; of course, plastic molds disassembly is a basic work in mold maintenance.

Do you know how to disassemble plastic molds? And what you should pay attention in moulds disassembly? When you disassemble theplastic moulds, you need to pay attention to following matters.

It is necessary to print the mould assembly drawings, clear up each of the parts in the plastic molds and the principle of operation as well as the assembly relationships.

According to the parts list on the assembly drawing, preparing the necessary disassembly tools.

Analysis the plastic injection moulds, learn the injection type, such as normal hot runner, valve gate or cold runner, and check the parting line and ejector system. Make a disassembly order list before do it.

When you disassemble the plastic mold, placing the mould on rubber mat or low hardness plane workbench. Parting surface to be parallel with the table; that means guide pin should perpendicular to the workbench. It can protect the mould parts, such as ejector pin, if the mould is not in correct direction, small pin will be easy to be bend.

Usually, you need to separated the cavity and core, and disassemble plastic injection moulds from back side, it means start disassembling from the ejection and injection systems.

If you don’t know about the mould well, you need to mark all the removed parts, and put in sequential, it will be convenient for installation and it can avoid mistake when you assembling the mould.

Tools to be used correctly make the force balance when you rotating or beating, don’t forcibly disassemble the undetectable parts.

If the tool needs to reach to cavity or core surface, be sure to use less hardness tool than the core cavity, usually, we suggest copper.

If you don’t have any mould engineer in your company, it is not rational to do plastic molds disassembly without any technical support. We suggest you send injection molding molds to local mould workshop, or do the plastic molds disassembly under guidance of mould manufacture.