Advantages and disadvantages of hot runners

Advantages

Shortened cycle time

The cycle time is shortened because there is no limitation on the cooling time of the sprue system, so the part can be ejected in time after it is formed and cured. Many thin-walled parts produced with hot runner molds can be molded in less than 5 seconds.
 

Plastic savings

In a pure hot runner mold, there is no production cost because there is no cold sprue. This is especially significant for applications where plastic is expensive. In fact, the major international hot runner manufacturers have grown rapidly in an era when oil and plastic materials were expensive in the world. This is because hot runner technology is an effective way to reduce material costs.
 

Scrap reduction

Reduce scrap and improve product quality. During the hot runner molding process, the plastic melt temperature is accurately controlled in the runner system. The plastic can flow more uniformly into each cavity, resulting in consistent quality parts. Hot runner molded parts have good gate quality, low residual stress after release, and low part distortion.
 

Production automation

The elimination of subsequent processes facilitates production automation. The finished part is formed by the hot runner mold, so there is no need to trim the gate and recycle the cold sprue. It is conducive to production automation. Many foreign product manufacturers are combining hot runners with automation to greatly improve production efficiency. Many advanced plastic molding processes are developed on the basis of hot runner technology. Such as PET preform production, multi-color co-injection in the mold, multi-material co-injection process, STACK MOLD, etc.

Disadvantages

Although hot runner molds have many significant advantages over cold runner molds, mold users also need to understand the disadvantages of hot runner molds. To summarize, there are the following points.

Increased Costs

Hot runner components are more expensive and the cost of hot runner tooling can increase significantly. If the part production is small, the mold tooling cost ratio is high and economically uneconomical. MoldDauber WeChat Editor For many mold users in developing countries, the high price of hot runner systems is one of the main issues affecting the widespread use of hot runner molds.
 

High equipment requirements

Production process equipment requirements are high, hot runner molds need precision processing machinery for guarantee. Hot runner system and mold integration and cooperation requirements are extremely strict, otherwise, the mold in the production process will have many serious problems. Such as poor plastic sealing leads to plastic overflow and damage to the hot runner components interrupting the production, and the nozzle inserts are not well-positioned relative to the gate leading to a serious decline in product quality.

Complex operation and maintenance

Compared with cold runner molds, hot runner molds are complicated to operate and maintain. If the use of improper operation is very easy to damage the hot runner parts so that production can not be carried out, resulting in huge economic losses. For new users of hot runner molds, it takes a long time to accumulate experience in using them.