Injection molding machines are expensive to purchase, require a lot of factory space and a significant amount of electrical energy. Additionally, installing and operating injection molding machines is a highly subjective task, with significant setup costs each time the mold is set. Starting and shutting down such machines can be very costly and technicians and/or operators are always directly involved in these activities. When an injection molding machine is started, an initial configuration of the machine is usually made (for example, screw speed, screw sleeve temperature, injection pressure, etc.), followed by a “cleaning” operation, which an operator first confirms. The injection molding machine is not attached to a mold and then begins to process the plastic, but discards the resulting molten plastic until the operator decides that the exit plastic looks hot enough and has a low enough viscosity to begin molding the test pieces. A large number of test pieces are then produced for inspection and/or analysis to determine if the machine is configured to produce parts with the intended properties (e.g., exact fit of the intended part shape, density, flexibility, etc.). Accordingly, machine settings are usually made for mass production of the part.
The injection molding application described above is subject to significant problems as various parameters affecting the part can change during mass production of the part. For example, the operator’s settings may not be sufficient to keep the injection molding machine in a condition that ensures the consistency of the part. In particular, it may not be possible to adequately determine whether the plastic is heated homogeneously enough to produce acceptable parts. In addition, since the composition of plastic raw materials naturally varies, part production may need to be diversified according to variations in plastic raw materials. In addition, the various injection molding parameters (whether set by an operator or not) are often interrelated to produce acceptable parts. For example, (a) nozzle injection pressure and plastic flow rate are inversely proportional, (b) plastic flow rate and plastic temperature are generally directly related, and (c) changes in screw rotation may often be directly related to plastic temperature, but what happens to plastic heating by shearing the plastic in this screw sleeve? extent to which it is carried out. Accordingly, it is very difficult to effectively and consistently configure a conventional injection molding machine to produce parts of acceptable quality, and the effort required to configure such a machine for very small quantities can become unacceptably expensive.
Accordingly, it would be advantageous to have an injection molding system and method of operation that is substantially less expensive to manufacture and operate. Additionally, it is desirable that such a system and method be less dependent on operator trial and error to configure such systems to produce parts of acceptable quality.
