Open automation technology with EtherCAT: perfectly suited to the additive manufacturing of plastic parts

The PC-based control principle

With PC-based control technology, we offer comprehensive system solutions in various performance classes for the automation of all types of plastics machines. The basic principle is based on a powerful industrial PC, a high-performance fieldbus connection with the connected peripheral devices for sensors and actuators, and the software for engineering and real-time control. The control platform is supplemented by an extensive portfolio of drive components. TwinCAT automation software bundles all necessary functionalities such as PLC, motion control, robotics, measurement technology, image processing, and HMI. Our technology is based on IT standards and has the necessary openness to implement intelligent production concepts according to Industrie 4.0.

Due to the high performance of modern processors, which we install in all of our PC series, computationally intensive applications can easily be integrated into the control platform. Plastics machine manufacturers benefit from the continuous increase in the performance of PC processors: Shorter sampling times are already increasing the quality of the end product today and will be the requirement for the realization of self-learning machines in the future. The possibility, for example, to completely simulate an injection molding machine in the virtual design process saves time during development and commissioning.

EtherCAT: World standard for plastics machines

The EtherCAT technology was launched on the market by us in 2003 and made available as an open standard for automation technology. With outstanding performance, flexible choice of topology, comprehensive diagnostics and simple configuration, EtherCAT is ideally suited for use in plastics machines. We offer the largest number of EtherCAT-compatible automation modules for I/Os and for drive technology.

EtherCAT is one of the most widely used standards in plastics technology. A large number of EtherCAT-compatible sensors and actuators are available on the market, which guarantees a high level of investment security. Particularly interesting for electrically driven injection molding machines is the problem-free connection of drives from third-party suppliers. Other fieldbus systems can also be integrated as communication layers via EtherCAT.

The fast and high-precision Beckhoff control solution eXtreme Fast Control (XFC) is based on EtherCAT and special I/O modules optimized for XFC that record signals or trigger actions with high accuracy. With I/O response times under 100 μs, XFC enables very fast and extremely deterministic reactions and thus contributes to process optimization.

Maximum production efficiency with XFC

The fast, high-precision eXtreme Fast Control Technology (XFC) developed by us reduces the raw material consumption and increases parts quality. I/O response times of less than 100 µs can be achieved with a powerful industrial PC, the ultra-fast EtherCAT I/O terminals, EtherCAT as the communication system and the TwinCAT automation software. Logging of highly variable input signals with high temporal resolution enables precise control of the injection molding process. Fast algorithms enable the magnitude and trend of the control value to be precisely calculated as a function of the switching event time. The working window becomes narrower, while part weight fluctuations and raw material consumption are reduced. High-precision servo drive technology, in conjunction with XFC, increases the reproducibility of the injection molding process even further. XFC also enables the integration of measurement technology into the machine control system, eliminating the need for special hardware. This way, it is possible to implement a cost-effective solution for condition monitoring, for example, which can extend the service life of machines and minimise downtime through preventive maintenance.

The acquisition of rapidly changing input signals with high temporal resolution makes it possible, for example, to precisely control the injection process in injection molding machines, especially with servo-electric drive technology. Fast algorithms enable the magnitude and trend of the control value to be calculated precisely as a function of the switching event time. This reduces part weight fluctuations and material consumption.

The oversampling technology based on XFC makes the signal curve exactly determinable. In combination with the timestamp function of EtherCAT, which links each event with a precise point in time, the reproducibility of procedures is increased significantly compared with conventional solutions.

TwinSAFE: The open and scalable safety technology

With TwinSAFE, we have implemented a consistent safety concept that integrates safe functionalities into the non-safety-related control architecture. Separate safety controllers are thus superfluous. The typical safety functions can be programmed and configured on the EL6910 TwinSAFE Logic or the compact EK1960 safety controller, based on standard safety function blocks according to the safety requirements. The Beckhoff safety solution accelerates the engineering process, as the safety-related requirements of different machine configurations can be realized by software. All our safety controllers are suitable for applications up to SIL 3 according to IEC 61508 or PLe of ISO 13849-1 and meet the EN 201 standard for injection molding machines.

Safety technology seamlessly integrates into the terminal segment via the TwinSAFE I/O modules, whereby safe signals can be mixed with standard signals as required. This benefits, for example, blow molding machines or production cells with control cabinets in different installation locations. Due to its scalability, the Beckhoff safety solution is suitable for expansive, complex systems with distributed I/Os as well as for small injection molding and blow molding machines. One safety logic is sufficient here to realize the complete safety technology. The compact EK1960 safety controller is particularly suitable for injection molding machines with hydraulic and/or electric drives. It allows the direct control of digital switching valves with a load of 2 A, such as those used in core pullers. With the help of the TwinSAFE SC technology, signals with a low safety level can be used redundantly for safety tasks.

Image processing integrated into the controller ensures the quality of the parts in plastics processing

Optical quality monitoring has long been known in plastics technology. However, due to integration costs and the lack of complete solutions, it has not yet established itself as a standard. The approach of PC-based control technology offers the ideal solution here: with TwinCAT Vision, Beckhoff integrates the image processing functionalities completely into the familiar engineering environment of the machine programmer, which makes programming and testing much simpler. All control functions derived from image processing, such as the exact determination of the position of the workpiece as well as the triggering of the camera and the light source, are synchronized in real time. This is a key advantage of the integrated image processing solution over separate systems.

The vision solution from Beckhoff is ideally suited in the plastics industry for process monitoring, e.g., for the ejector, for determining the part geometry and for position orientation.

Advantage through TwinCAT Vision

• Improvement in quality: Precise measurement and exact optical inspection ensure compliance with the process parameters.
• Increase in efficiency: The synchronous inline measurement of parts without a separate measuring station improves efficiency.
• Quality assurance: Applications such as Track & Trace enable the traceability of product quality for each individual part, such as is required for safety-critical applications in the medical technology sector or for special automotive parts.
• Temperature measurement: The surface temperature of plastic parts can be determined with the help of thermal imaging cameras.
• Machine Learning: Inferences between machine settings and part geometries are a prerequisite for the development of learning algorithms as a milestone towards intelligent, self-learning machines.

Industry and customer-specific Control Panels and Panel PCs as a unique selling point for your machine

The ergonomic operation and the unmistakable appearance of a machine play a significant role in its success on the market. In addition to design and color, the Control Panel is of great importance as the front end of a machine. More and more mechanical engineering customers therefore want an industry or customer-specific user interface as a unique selling point. Based on an extensive portfolio of standard Control Panels and Panel PCs, Beckhoff offers a wide range of solutions with regard to technical form and design. A panel design that matches the appearance of the machine in color and dimensions underlines its innovative character. There are no limits to the implementation of the customer's wishes: from the customer-specific company logo inserted in the factory and the color scheme matching the machine design, to the completely individually designed panel on the basis of an individual device construction.

In order to meet the needs of the plastics industry for ergonomic operation, Beckhoff offers Control Panels and Panel PCs that are optimally suited to the various processes. The needs-based design of the standard panels through the integration of manually operated push buttons and switches makes machine operation more comfortable. Large display sizes enable clear and transparent monitoring of the manufacturing process: whether by calling the virtual 3D representation of the part to be manufactured or through the integrated image processing, which provides an up-to-date picture of the production progress.

Safe and accurate reading of thermocouples

Requirements in the injection molding technology prompted the development of the Fieldbus Modules from the FM33xx series. The 12- and 32-channel input modules allow the safe and accurate reading of thermocouples on injection molds or on plasticizing cylinders via fieldbus. The multi-thermocouple connector is accommodated in a compact, splash-proof housing. The circuit of the Fieldbus Modules can operate thermocouple sensors in 2-wire technology. Linearization over the entire temperature range and cold junction compensation is carried out in the module. The temperature range can be selected freely. The error LEDs indicate a broken wire. In order to increase operational reliability, the thermocouple inputs provide protection against accidental connection of the power supply for the heating elements. The cabling costs are reduced by eliminating compensation cables.

The FM33xx-B110 thermocouple Fieldbus Modules with EtherCAT interface are supplied with voltage via separate M8 connectors and are daisy-chain-capable on both the power supply and EtherCAT side, i.e. several modules can be wired in series in a line topology. The FM33xx-B310 Fieldbus Modules have a PROFIBUS DP interface with a data transfer rate of 12 Mbaud. Data is mainly exchanged cyclically, although acyclic services (DP-V1) are also available for parameterization and diagnosis.

Efficient energy management

The energy consumption in plastics processing varies depending on the process, but it is generally very high and represents a considerable cost factor. Energy efficiency is therefore an essential building block for sustainable production. Beckhoff provides suitable technology for the continuous monitoring of energy consumption as well as for the detailed consumption analysis of new developments.

Beckhoff offers performance and cost-optimized software and hardware components for this purpose:

• The TF3650 TwinCAT 3 Power Monitoring software library is a PLC library for the evaluation of raw current and voltage data provided by the EtherCAT Terminals. Appropriate function blocks are available for calculating RMS values for current, voltage and power.

The following EtherCAT Terminals are particularly suitable for the plastics industry:

• The EL3443 and EL3453 EtherCAT Terminals enable the direct measurement of all relevant electrical data of the mains supply in the EtherCAT I/O system. The integrated monitoring of the energy efficiency of a plant is thus simple to implement.
• The EL3773 and EL3783 power monitoring terminals are designed for the detailed acquisition of the condition of a 3-phase AC or DC grid.

EtherCAT I/O modules integrate temperature control, energy measurement and safety technology into the control platform

In 1995, Beckhoff launched the Bus Terminal, which has since become one of the most important technology standards in automation technology. This was followed in 2003 by the development of the EtherCAT fast communication system. Launched by Beckhoff as an open system, it became a global standard in automation within a few years. An extensive EtherCAT I/O Terminal portfolio is available to users that is extremely well suited for automating every functionality in plastics machines and their peripherals in terms of both its performance and variance.

• EL3318 for temperature measurement
  The EL3318 EtherCAT Terminal is ideal for temperature measurement via thermocouples. The 8-channel input terminal with integrated cold junction compensation is very compact in its design and measures temperatures with high accuracy and high signal-to-noise ratio.
• EL3403 and EL3446 for power measurement
  The EL3403 three-phase power measurement terminal can be used to measure and optimize the power consumption of a plastics machine. In conjunction with the TwinCAT Plastic Processing Framework, the EL3403 is used for the cost-effective Condition Monitoring of the heating tapes through sequentially alternating testing in operation. In traditional control structures, the power measurement terminal can also be used for current measurement. The EL3446 is available for simple monitoring of the heating tape function. In combination with the voltage measurement in just one power measurement terminal, the power consumption of individual machine components can be recorded cost-effectively by means of current measurement. The Beckhoff SCT current transformers (SCT2xxx, SCT1xxxx) enable assembly of the appropriate combination of sensor and power measuring terminal without requiring detailed knowledge.
• EL3255 for position detection
  The EL3255 EtherCAT Terminal allows potentiometric position detection. Due to its integrated power supply, the terminal delivers precise results (voltage values) even in environments with high interference fields. The EL3255 is particularly suitable for injection molding and blow molding machines with hydraulic drive technology.
• EL6224 IO-Link terminal
  IO-Link is an inexpensive fieldbus for the reading of sensors with low real-time requirements. A preferred application, for example in extrusion, is the reading of melt pressure and melt temperature via the EL6224.
• TwinSAFE terminals for integrating safety technology into the controller
  Due to its scalability, the Beckhoff safety solution is suitable for expansive, complex systems with distributed I/Os as well as for small injection molding and blow molding machines. One safety logic is sufficient here to realize the complete safety technology. The compact EK1960 safety controller is particularly suitable for injection molding machines with hydraulic and/or electric drives. It allows the direct control of digital switching valves with a load of 2 A, such as those used in core pullers.

Drive systems for highly dynamic positioning tasks

In combination with the motion control solutions in the TwinCAT automation software, Beckhoff drive technology represents a complete drive system for all applications in plastics technology. With EtherCAT as a fast communication system, it is suitable for single and multi-axis positioning tasks with highly dynamic requirements. Due to its scalability, the Beckhoff drive technology enables machine manufacturers to design their drive solution to suit the required performance.

The AX5000 and AX8000 servo drive series offer maximum performance and dynamics with powerful EtherCAT system communication. The integrated, fast control technology of the AX series supports the execution of high-precision positioning tasks, such as those required in the field of film production: The smoothing rollers, which smooth the extruded film before winding, must be adjustable in the submillimeter range. The AX5000 offers the optimal solution for ultra-fast removal processes. The flexible concept of the AX5000 with 1- and 2-channel units as well as the variable motor power ensure a cost-optimized design. The drives from the AX8000 series are predestined for compact, modular drive units and for Cartesian handling devices.

In the lower performance range, the EtherCAT servo terminals, which offer a complete servo drive in the standard terminal housing, represent a drive solution that is both compact and inexpensive for low part weights or for additional units with low power consumption.

TwinCAT: the integrated engineering and control platform

TwinCAT integrates all engineering and runtime processes on a central software platform. This applies to programming, configuration, real-time environment and all runtime modules. By programming in the common IEC PLC dialects and integrating C/C++ algorithms, machine manufacturers can freely choose the most suitable programming method depending on the qualifications of the programmers, the service strategy and the need to protect expertise. With the integration of MATLAB^® and Simulink^®, controller concepts are developed based on models, thus contributing to virtual machine design. By using Microsoft Visual Studio as integrated programmer workbench, different version control systems are supported and teamwork is simplified. For series production, TwinCAT offers open interfaces for the integration of commercial IT systems for machine program generation.

• Extensive TwinCAT libraries for motion control save development time thanks to tested and optimized algorithms. The TwinCAT PTP and TwinCAT NC I supplements are ideally suited for handling applications with Cartesian robots. Ready-to-run solutions are available with TwinCAT Kinematic Transformation for other robot kinematics, such as SCARA, Delta and articulated arm.
• Commissioning and service processes are accelerated and improved with TwinCAT Scope, a software oscilloscope fully integrated into the TwinCAT system architecture, and thus contribute to increasing machine quality.
• TwinSAFE software-based safety technology simplifies the wiring of complex systems; variants can be mapped in software. This allows, for example, the modular development and commissioning of production cells. Documentation is also simplified and adaptations to additional customer requirements can be implemented quickly.
• The integrated, browser-based TwinCAT HMI visualization solution enables convenient development and maintenance of visualization objects. The information is presented either on the machines and systems or via the internet using a web browser.
• TwinCAT IoT provides the prerequisite for data aggregation in the cloud or locally in the production plant. TwinCAT also includes standardized communication protocols for cloud applications.
• The collected data can be specifically evaluated using TwinCAT Analytics.
• The TwinCAT interfaces to machine learning algorithms allow the use of AI methods in the traditional control environment.

TwinCAT Motion Control: perfectly suited for all drive tasks in plastics technology

Motion Control has been an important part of Beckhoff's software engineering tools for many years. With TwinCAT PTP and TwinCAT NC I, the requirements of electric drive technology in plastics machines and their peripherals are perfectly covered. A wide range of software modules for different tasks such as cam plates, synchronization and interpolating movements of several axes are available. NC PTP is perfectly suited for the widely used Cartesian removal systems; integration into the machine controller of the processing machine is easily feasible. The TwinCAT Plastic Application Components are available for stand-alone handling applications. As an industry-specific extension of the TwinCAT, they support the widely used Euromap interfaces between injection molding machine and robot, either as Euromap 67 or in the future as Euromap 79 (OPC 40079).

Fast removal processes, such as in-mold labeling with the help of side removal handling, are optimized with PC- and EtherCAT-based control technology: EtherCAT as a fieldbus with virtually delay-free synchronization leads to extremely short cycle times.

Following the philosophy of open automation technology, TwinCAT Motion Control is a tool for the design of production cells that allows the integration of Beckhoff drive components as well as third-party components. TwinCAT NC-PTP is a suitable engineering tool for a variety of drive concepts: from simple switched axes and stepper motors or frequency converters to servo drives.

Different encoder technologies with fieldbus interfaces or direct connection via I/Os are supported. This makes it possible to design production cells modularly, flexibly and at an optimal cost according to market requirements. In particular, the linking possibilities of master and slave axes in almost any structure as well as the powerful and diverse motion functions of TwinCAT cover wide-ranging applications in outstanding fashion. With the Flying Saw software library, for example, trimming units in extrusion lines can be perfectly synchronized. Powerful tools such as the TwinCAT CAM Design Tool and the TwinCAT Scope support machine design and commissioning. PLC libraries with function blocks according to the PLCopen Motion Control standard facilitate programming and save engineering effort through the reusability of the modules.

Modular software solution for the plastics industry

With the TwinCAT 3 Plastic Framework, we offer a modular software solution for the control of plastics machines that minimizes development effort and maintains the open nature of Beckhoff architecture. The TwinCAT 3 Plastic Framework brings together our many years of expertise in plastics, seamlessly integrating important industry-specific functions into the established TwinCAT environment. As a result, plastics machines can be programmed, visualized, and controlled on a single platform.

The TwinCAT 3 Plastic Framework contains three software libraries: TF8540 enables comprehensive software-based temperature control in plastics processing. TF8560 is a technology package that provides all the components for controlling motion functions in plastics machines. TF8550 is an HMI package specially developed for the plastics industry that enables the visualization of typical processes with minimal engineering effort and integrates seamlessly into the other technology packages. Integrated, application-specific templates and sample code for various plastics applications facilitate project planning and programming, and are made available free of charge via the TwinCAT 3 Plastic Application. Of course, existing templates can also be used and your own process expertise can be integrated.