It’s no surprise that the advent of interconnected devices and advanced computing are affecting common manufacturing processes like extrusion. This shift has been going on in extrusion for longer than most people realise, driven by the demanding medical device market. Automatic online gauges with limited feedback loops have been common for more than twenty years, however, most of these devices still required significant operator interaction and were only capable of simple adjustments to correct for one variable. This is no longer the case.
New extruders typically have Human Machine Interface (HMI) control units in addition to Programmable Logic Controllers (PLCs) that are able to digitally control multiple variables on the machine simultaneously. They are generally capable of network connectivity and can send and receive data with proper IT integration. The same is true for the other pieces of equipment typically on an extrusion line. With a sufficiently skilled IT department, it is possible to log this data, analyse it, and transmit instructions both back to the equipment it originated from and to other equipment on the same line - the critical step to take an automatic feedback line and transform into an industry 4.0 capable line.
This process is not easy. There is still no standardised language from PLCs, which creates the need for an integration program that can talk the language of each piece of equipment on the line. This data then needs to be translated into a format that is capable of analysis by both software and recognition by the HMIs human beings use to control the system.
Once the data is translated and aggregated, software needs to be able to analyse and direct the data. That is, it needs to take data and make it into useful information. This information can be further mined with proper analytics to go from reaction to prediction resulting in the adjustments being done well before parts go out of specification and virtually eliminating scrap from the process.
However, moving from reaction to prediction requires significantly more computing power and a better understanding of the process. Unfortunately, there is no off-the-shelf solution for this type of data analysis and integration which leads to further issues in validation of software controls and tracking as updates are released.
Taking a sample case from our factory, we have a line with online OD and ID measurement and a fully network capable extruder, blender, puller, and cutter. The line is capable of tracking material usage and automatically issuing material as it is consumed. It is also capable of varying the screw speed or the puller, depending on the product, to maintain the target for the OD and wall. This same measurement information can then be sent electronically to populate a Certificate of Analysis for the product, showing the customer the product meets quality requirements without the need for secondary measurement by operators or technicians. This level of interconnection allows an extrusion process to run with very little operator interaction – but even with this level of sophistication, there is more that can be done.
Additional sensors added to lines can control and predict things beyond the ordinary running conditions. The sensors can translate data into a targeted preventative maintenance system instead of using run hours or calendar days to approximate when failure is likely to occur. They can also send a signal to alert an operator when more material is needed as part of a scheduled delivery, instead of just turning on a light.
It is important to understand that industry 4.0 is more of a journey than a check-the-box upgrade or option package for equipment. You can’t buy an industry 4.0 line off-the-shelf because of the amount of integration needed both between difference pieces of equipment and with things not on the extrusion line.
It is not always clear what benefits you will be able to measure before the journey begins, but if you start the process you will definitely find benefits. You will also find there is no going back to a factory where you are blind to all the information available from your systems and equipment. The future is integrated, and it will be full of information that will make parts both less expensive and more reliable. That is where extrusion and industry 4.0 meet.