Milling machine

Our high-resolution BML magnetic encoders ensure the extremely precise position and speed monitoring at various positions: the processing axes x, y, z and B.

The high-precision magnetic encoders, which consist of a sensor head and magnetic tape, measure without contact, are wear-free and, in contrast to expensive optical systems, do not require protection measures. Very rugged and insensitive to dust, oil and deposits, they ensure high operating reliability at a low price. They are suitable for high accelerations and insensitive to vibrations and oscillations. This was a crucial factor for the manufacturer.

The mechanical engineer found the thought of being able to use a measuring system for all axis applications highly enticing. This is because the final assembly of the individual system components follows the same principle, thus substantially simplifying series production as well as commissioning the machine.

To ensure efficient processing of the workpieces, a four-sided workpiece carrier is used, which carries workpieces on each side. To correctly position workpieces successively for milling, the workpiece carrier is rotated endlessly by 360 degrees by means of a torque motor. In addition to this, an inductive coupler transfers the energy via an air gap without contact. Cable wear and cable breakage are not an issue.

An incremental BML S1F with a magnetic tape ring, which is integrated in the mounting of the rotational shaft, monitors the highly dynamic, super-rapid and precise travel movements. Its high-precision measurement results enable optimal control quality, thus providing precise position feedback such that the drive runs as smoothly as possible.

The manufacturer benefits from the compact design, the large air gap from the sensor head and magnetic tape, as well as the magnetization on the customized function part. The optimum integration into the machine design allows a large measuring radius and thus very high resolution to be achieved.

The clamping device in the electric motor, which releases the workpiece carrier, has an absolute disk. Its precise absolute measuring signal, which is present immediately after being switched on, shows the exact position of the clamping device without a reference run.

To avoid needing hydraulic or pneumatic systems, electrical drive technology was used. It delivers high performance, is energy efficient and also easy to monitor.

Our BIP inductive positioning system performs the clamping range monitoring of the tool. It monitors the current clamping state via a steel target. This immediate information ensures that the workpiece carrier is always securely locked.

In addition to being insensitive to contamination, the positioning system also provides reliable position monitoring with high repeat accuracy at a high traverse speed. The automatic tool changing and the reliable processing are reliably ensured in this way.

This solution is economical and impressed right from the start.

A BIC inductive coupler provides energy and signal transmission. This makes it possible to query the inductive sensors and control the valve terminals in the workpiece carrier.

Our inductive coupler is ideal for moving machine parts. This is because the non-contact transmitter sends both energy and signals reliably and without wear across an air gap, thus supporting high system availability.

With its IO-Link interface, it works bidirectionally and transmits data in both directions. This makes it possible to control the actuators and collect the sensor signals at the same time.

Because the quick-disconnect units are easy to handle thanks to plug-and-play, new requirements, such as tool changing, can be implemented in a short period of time. This enables high cycle rates and increases the flexibility of workflows.

To precisely position the workpiece carrier on the three processing axes, the BML S1F magnetic linear encoder ensures the optimum control quality of the linear motor.

In addition, the mechanical engineer can quickly and flexibly install the compact systems. This is because the handling is easy and allows for plenty of leeway. Another advantage of the system: The magnetic tapes can even be individually cut to length on site.

A BML S1F incremental magnetic linear encoder monitors the precise positioning of the tool changer on the x/y/z axis. This makes it possible to quickly and reliably change tools. This is because the desired changing position is always ensured.

Combining the BML direct measuring system with a simple ball screw and a toothed belt makes high accuracy possible at a very good price.

Ultrasonic level sensors with an IO-Link interface ensure that the milling machine is reliably supplied with coolants and lubricants. The sensors continuously detect the exact fill level value of the processing liquids and digitally relays it to the control unit with high signal quality. The minimum and maximum value are reliably adhered to as a result.

With IO-Link, the machine operator always has an overview. This is because the communication standard continuously provides both process data and diagnostics information.

Power is supplied by an IP67 power supply with IO-Link that can be used directly in the field under rough conditions and is thus outstandingly suitable for decentralized installation without control cabinets. With IO-Link, the power supply can be conveniently monitored from the control center and thus also be installed in hard to access locations.

The Heartbeat® function allows the machine operator to continuously monitor wear factors. It displays load and stress conditions (stress level) as well as the current load (load level). In addition, the Lifetime display provides information on the remaining lifetime. Unexpected failures with an interruption of production are therefore a thing of the past.

In order to continuously monitor various operating states and different stages, it was decided to opt for the SmartLight LED signal tower. This is because its color spectrum makes detailed displays possible and also signals trends and progressions of physical parameters. Its ease of handling is simply unbeatable. Modes and colors can be changed during operation, i.e. without mechanical modifications. And its colors and zones can be configured individually in terms of number, size and color definition. All of this is done using its IO-Link interface.

For example, the SmartLight indicates how long it will take until the next time the machine is serviced. The flashing frequency can be used to determine whether the parts container still holds enough parts for processing. And the fill level display signals how much lubricant is present and when the container needs to be refilled. This provides additional security during machine operation.

The high degree of automation of the machine with a wide variety of sensors required a high-performance and simultaneously efficient wiring concept. The mechanical engineer also wanted to be able to efficiently connect the milling machine to other machines of its type to make comprehensive communication possible.

IO-Link provided the ideal solution. This is because cost-effective three-wire unshielded industrial cables are sufficient for the connection. And simple M12 plugs are sufficient for connecting a wide variety of devices. Thanks to the universal interface, intelligent sensors can be configured centrally, diagnostics information can be transmitted from the sensor to the control unit and process data can be transmitted digitally with high signal quality.

Of particular interest to the mechanical engineer and the machine operator: The combination of IO-Link with high-performance fieldbus technology allows data to be reliably and flexibly exchanged across systems.

To collect the sensor signals as cost-effectively as possible, the mechanical engineer uses IO-Link sensor hubs with 16 freely configurable inputs/outputs. In particular, the active distributors in the rugged metal housing in IP67 are excellently suited for the harsh environment of the milling machine. In addition, IO-Link sensor hubs in IP20 with eight freely configurable inputs/outputs are used in the switch cabinet. This is because their design allows them to be integrated perfectly into limited space conditions.

These hubs are connected via plug-and-play to an 8-port IO-Link master, which relays the sensor information from eight hubs with up to 16 sensors each to the control unit. Up to 136 inputs/outputs can be connected per node. A particularly efficient aspect: The electrical engineer only needs one bus address for this purpose.

The easy data management was a reason why the mechanical engineer envisaged automated tool management with RFID. The high efficiency with optimum tool utilization and maintenance were no less impressive. Especially because the highly efficient use of tools contributes to an increase in productivity.

This is because the tool management ensures that the right tool is in the right place at the right time. All relevant tool data, such as availability, degree of wear or remaining service life are stored in real time during use on a data carrier that is firmly connected to the tool. All data can be recalled at any time. And missing assignments become a thing of the past.

This paperless, reliable tool identification with a high value creation factor is ensured by our BIS M high-frequency system with 13.56 MHz. Specifically designed for metal surroundings, it manages high speeds excellently in harsh environments. Thanks to the wide variety of available components, the perfect system was quickly assembled, tested and put into operation.

For quality assurance and for the sake of efficiency, the workpieces should be fed and tracked fully automatically. The traceability of the production process also played an important role when selecting the technology.

RFID proves to be a key technology here. This is because RFID automatically documents the production history of all manufactured parts as well as all materials and equipment used together with the time, location and process. Thanks to this real-time information, defective parts can be ejected, repaired and fed back into production during the production process.

To this end, every workpiece receives a data carrier of the BIS M high frequency RFID system. These industrial-quality high-speed data carriers provide unlimited read/write cycles and support high output rates and fast cycle times. Designed for metal surroundings, they are immune to metal dust, water and oil. They are therefore ideal for identification tasks when small metal parts are being milled.

Each step of the process change is recorded and comprehensible. The overall manufacturing process is thus transparent, and the material flow can be controlled across all areas. An optimum process from the unfinished part to the finished product is now possible. Milling machines of this type can thus be integrated perfectly into a smart factory.