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Cold Runner and Hot Runner system for Mold

Advantages & Disadvantages of Cold Runner and Hot Runner system

Cold runner systems are, typically, relatively more cost effective than their hot runner counterparts. The total cost to produce a molded item and lower general maintenance expenditures both add to the overall reduction in cost. They are also capable of handling a wide variety of commodity and engineered thermoplastics. Additionally, cold runners are more flexible than hot runners since runner and gate locations can be easily changed or upgraded, allowing for faster design changes.

Injection molded parts lifted by an automated armHowever, one of the significant disadvantages of cold runner systems is the actual production of the runner itself. In two-plate cold runner systems, the runner needs to be manually separated from the finished part after each run. If these runners are not reground and recycled, the plastic material is wasted after each run. Furthermore, the removal of the sprues and runners – and the time it takes to recycle each runner – adds to the cycle time, resulting in a slower production time than hot runner systems.

Hot runner systems generally possess significantly faster cycle times than cold runner systems. The elimination of the runners greatly reduces the number of post-production activities such as runner and sprue removal, regrinding, and recycling. The lack of runners also reduces potential waste during the molding process and eliminates the need for robotics to remove runners. This contributes to an overall cost reduction and increases the efficiency of the mold automation process.

Also, because each runner feeds a dedicated mold, hot runner systems are capable of fabricating larger parts. Hot runners, however, tend to be more expensive than cold runner injection mold systems. Because each hot runner feeds into a dedicated mold, additional internal or external heating sources are required to keep the runners at a consistent temperature.

Additionally, the tooling cost is usually higher than that of cold runner systems. As a consequence, molded parts can be more expensive to produce, thereby increasing the cost of the total production volume. The complex nature of the hot runner equipment also means that it requires more careful inspection and maintenance, leading to an increase in maintenance costs and potential downtime. Also, internally heated hot runner systems may not be suitable for thermally sensitive polymers since there are areas where material could stick to the surface and become overheated.

Kayou acts as your injection mold making and plastics moulding solution provider in China, offer you "one-stop" OEM service for your project from mold making, mouldings parts production, printing, assemble and package service with timely delivery and cost effective. With over 20years experience in automotive, medical, construction, home appliance, consumer electronics, Kayou can bring great values to your business.


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