Meet the Robots: Advantages of autonomous production methods in plastic injection molding
Do robots ever get bored at work? Obviously, that is a rhetorical question. Robots execute predefined actions more precisely, safely, cheaply and repeatably than humans. Their powerful and yet precise arms can do physically straining, repetitive and tedious jobs efficiently, freeing up humans to focus on more creative and meaningful aspects of work.
Robotic manufacturing has increasingly become the standard way of doing things in the injection molding industry. There are of course still some production processes in which parts are simply ejected and dropped – but these are suitable only for parts that are stable and impact-proof. Many modern parts would not survive such an impact. By using robots to handle them, such risks can be avoided. Even simple linear robots can rapidly extract freshly injection-molded parts from the mold, and then deposit them gently and safely at their next destination.
Linear and articulated-arm robots
Companies will determine which robot to use, based on the part, as well as the quantity to be produced. Linear robots are particularly suitable for simple parts that are produced in high volumes. They are mounted on three axes and equipped with a rotary movement in the arm. As a result, they perform recurring work steps very quickly, but are limited in their mobility.
If a component requires several steps to complete, practitioners usually prefer articulated arm robots. Within their movement radius, they can move freely in all directions. If, for example, the injection-molded part still needs to be drilled, the articulated-arm robot grips the product and transports it to the drill with millimetre precision. If metal elements need to be attached, it transports the component precisely to the next station. The robot reliably performs all conceivable tasks until the end product is finished.
More autonomy through computer chips
Several robots often work on complex components in successive steps. The right communication is important here: In addition to network-based communication, machines can also communicate through the component itself. For this purpose, a computer chip is attached to the component at the first station in the production chain. The chip stores which tasks need to be performed and keeps track of which have already been completed. The robot at the next station can then read the chip and knows exactly what it needs to do. Such intelligent systems help ensure the quality of production: They reliably detect when an error or fault occurs during production and store this information directly on the component, and pass it on to a central location for further analysis.
Man and machine complement each other
We know from discussions with our customers: Companies that use robotics for injection molding processes quickly enjoy the benefits and are able to increase their production volumes. Error rates in the manufacture of components are significantly reduced, and production losses are lower. Automated injection molding systems register, among other things, the fill levels of the granulate containers and automatically ensure replenishment.
In addition, robots also reduce the risk of injury to humans. For example, when robot arms extract the still hot injection molded parts from the mold, or when they pre-heat some parts before the next production step. While strict precautions must be taken for humans to avoid skin burns and safety hazards, a mechanical arm can hold the molded part in the oven or under infrared radiators, without any issues. Collaborations between human workers and robots work smoothly, as well. During final inspections, for example, a robot arm can freely rotate heavy and unwieldy parts in all directions while a human inspects them or performs some final steps to obtain a perfect product.