Tizian 5.4 with Rexroth’s CNC system solution MTX developed completely virtually
A CNC machine for 5-axis simultaneous machining which is as compact as a stand-alone refrigerator, can be used in residential areas and is ready for the Internet of Things: the new Tizian 5.4 milling machine from medium-sized enterprise Cimt, located in Rosdorf near Göttingen, machines components for dental prostheses. It is the first machine in the dental industry to have been developed and tested completely virtually using a digital twin of Rexroth’s CNC system MTX.
It’s 6 p.m. and the last patient has just left the dental practice. The dentist inserts a changing magazine complete with 10 blanks and 20 tools into the Tizian 5.4. With a few taps on the multi-touch display, he loads the milling programs compiled during the day from the CAD/CAM system and hits START. The milling machine will produce crowns, bridges or telescopic prostheses fully automatically overnight.
A+B axis with 3D measuring probe
Customized user interface
“In order to be able to turn our ideas into reality, we need a completely open control system that gives us maximum freedom for designing the user interface and the interfaces to CAD/CAM systems and simultaneously provides us with the necessary performance for the fastest milling speeds on the market”, say Andreas Kirsch and Christian Heine, the Managing Directors and Owners of Cimt GmbH. Rexroth’s CNC system MTX was the best match. It is the top-performing CNC control system on the market and offers openness even in the control core thanks to the Open Core Interface technology. As such, Cimt has full scope to custom-design the user interface and prepare interfaces to the CAD/CAM systems normally used in the dental industry.
Virtual machine with HMI command elements
Magazine with 20 milling cutters and 10 blanks
Technological data of one of the 20 milling cutters in the magazine
Speed with precision
The compact machine consists of a cooled steel body with a mineral casting design, which enables a high level of temperature stabilization and accuracy. The machine is designed for the wet and dry machining of numerous materials, from NEM, titanium, steel, zircon, green ceramic, copper and graphite right through to plastics. Only HSC milling spindles are used for the cutting. A milling spindle optimized for dentistry with 1,500 W of power, increased torque and a maximum rated speed of 60,000 rpm reliably executes the milling work. A new generation of milling cutters combined with the force and the warp resistance of the Tizian 5.4 means that very high milling speeds can be achieved.
However, what’s more, the fully fledged machine tool must meet very special requirements. Dental practices and dental laboratories are often located in inner cities and residential areas. The Tizian 5.4 manages to run on a connected load of 16 A and, despite the servo technology, meets EMC regulations for residential areas. In addition, with a width of just 78 cm it also fits through normal door frames and, weighing in at just around 650 kg, it also takes into account the load-bearing capacity of any floors and ceilings below in residential buildings and commercial premises.
The CNC system MTX guarantees a combination of speed and precision. Its hardware is scalable in subtle increments and the most powerful version of it can control up to 250 axes in up to 60 NC channels with just one piece of control hardware. The system is based on open standards and features numerous predefined technology functions. Coordinated accordingly, the system solution encompasses a wide range of smart servo drives and servo motors as well as expandable I/O modules and a safety control.
First ever purely virtually developed dental machine
When designing the new machine, Cimt used Rexroth engineering services for programming, simulating and testing the CNC system. As such, the development time was reduced to just one year. Bosch Rexroth provides a fully fledged digital twin for each MTX. This enables machine manufacturers to simulate and optimize the system solution’s behavior together with all axis movements in advance with the STL Machine Builder and the MTX Operation Desktop without any control hardware.
“We also created a digital 3D machine model and together with Rexroth experts were able to construct and test the machine completely virtually”, remembers Christian Heine. “The Tizian 5.4 is the first machine in the dental industry to have been developed completely virtually.” This is true right across the board, from the design and dimensioning of the Bosch Rexroth ball screw assemblies right through to the full PLC and CNC programming in accordance with DIN 66025. The experts optimized the dynamics of all movements on their computers in order to achieve maximum productivity. It was not until after then that Akcurate began to assemble the first Tizian 5.4 models.
Connected for maximum availability
In addition to programming a special HMI for operators without any CNC knowledge, Cimt also makes it easier to operate the machine thanks to extensive connectivity. The MTX includes an OPC UA Client/Server as standard and already supports the new umati interface from the German Machine Tool Builders’ Association (VDW). This cross-manufacturer standard for machine tools enables customer or manufacturer-specific configurations to be used for customized mapping and transformation of parameters via standardized input.
Cimt can, if it so wishes, connect to the machine and carry out remote maintenance wirelessly via the Bosch Rexroth IoT gateway. In addition, users can call up information wirelessly using a web browser on any end devices. In the event that there are problems with a workpiece, the user can stop the milling work, unload the workpiece and initialize machining of the next blank. An integrated remote maintenance camera facilitates the work.
Know-how protected thanks to encryption
The precision of the Tizian 5.4 is particularly important to Cimt as a machine manufacturer: a tactile measuring probe which calibrates the milling machine and controls the quality of the milled parts is an important component of the machine. Expandable, fast I/O modules capture the signals and the MTX’s software automatically identifies if any subsequent milling is required. “We also need a high-performance control system here with sufficient computing capacity for processing process data in real time”, says Andreas Kirsch. “We are also simultaneously seizing the opportunity to protect our know-how with encryption technology.”
Author: Peter Berens
is group leader in industry management CNC systems for forming and additive manufacturing processes at Bosch Rexroth AG in Lohr am Main. He holds a degree in mechanical engineering and has been with Bosch Rexroth since 1990.
You must be a registered user to add a comment. If you've already registered, sign in. Otherwise, register and sign in.