Injection Molding Machines. Machine Selection and Process Optimization

Plastic injection molding involves filling the cold cavities of a mold with molten plastic, then demolding the resulting part once the plastic has cooled and solidified.

The mould cavities are filled by introducing molten plastic material under pressure into the mould cavities.

The temperature of the cavities is regulated to a value that cools the injected material.

The injection-molded parts, formed by the plastic material solidified in the cavities, are extracted from the mold by means of a mold opening and an ejection device.

The cost price of injected parts is closely linked to the hourly cost of the press and the cycle time. The hourly cost depends on the choice of press, and the cycle time is directly related to the setting.

With this in mind, this article describes how to select and operate a plastic injection molding machine. A theoretical and practical approach to choosing the number of cavities leads to press sizing and related engineering choices. The industrial and economic performances associated with these choices are specified. Detailed and rational press adjustment techniques are then proposed, explained and supported. The main process-related quality problems and their most common causes are discussed, leading to the most appropriate solutions and setting modifications for the general case.