Technical Papers

Accurate Control, Efficient Production

EST controls feature integrated servo controller for press applications in the automotive industry

Assembly press by EST
The new assembly presses by EST

The new assembly presses developed by the company EST GmbH allow short cycle times and optimal processing results in the automotive industry, amongst others. An innovative control is the core of such a unit. This control combined with the drive system SD2 by SIEB & MEYER guarantees high process accuracy. For this purpose SIEB & MEYER customized the well-proven drive system regarding construction dimensions and interfaces ensuring optimized interaction between the two solutions.

Since its foundation in the year 1994 EST GmbH develops forward-looking system solutions for the automation technology. The company focuses, amongst others, on complex data control and process solutions for screw tightening and press fitting processes. "EST is short for electronic screw tightening and control technology", says Stefan Nuding, CEO at EST GmbH. "More specifically, we offer customers branch-independent solutions for screw tightening, assembly or press fitting and measuring processes."

Best possible control not only for press applications

Recently EST developed a new assembly press that is designed primarily for the automotive industry: This forward-looking solution allows press fitting of, for example, seals and bearings in motor and gear housings. The assembly press has a very compact construction and therefore requires comparatively little installation space in the spatially limited production systems. Short cycle times of up to 250 mm/s make quick and efficient production possible. The work pieces are processed as accurate as possible on account of the electric drive, the integrated absolute encoder and last but not least the control system of the series flexE12, which is self-constructed by EST and also sold separately. "We cover different fields of application with only one control generation, for example screw tightening and press fitting as well as friction coefficient and path measurement", Stefan Nuding explains. "This is unique in the market." The modular design of both hardware and software of the series flexE12 along with the configurable sensor interface of the Profinet based units make that possible. Almost all centralized and decentralized control architectures of EST come with the integrated drive system SD2 by SIEB & MEYER to ensure best possible control.

A good choice for versatile processes

"Our customers expect highest precision when they purchase systems by EST ", says Stefan Nuding. "This generally applies to all industry sectors but especially to the automotive industry." As particularly accurate working is required, the drive system SD2 comes into play: In the assembly presses the drive solution ensures, amongst other things, optimal control of the press-fit depth and block force. SD2 is also essential in screw tightening applications: "When a screw is to be tightened at 500 revolutions per minute, the servo controller must do exactly that", Stefan Nuding points out. "Precise control is also essential to ensure repeatability of the processes."

A flexible drive solution with many advantages

With the SIEB & MEYER drive system SD2 EST has found the ideal complement for their controls. "SD2 is a universal drive solution for multi-axis applications", says Ralph Sawallisch, Key Account Manager Drive Technology at SIEB & MEYER. "The solution is designed to control synchronous and asynchronous motors with or without sensors and permits quick and easy adaptation to the individual case of application – whether used with linear motors, rotary motors or motor-driven machine tool spindles." With SD2 customers can implement high-speed applications up to 120,000 rpm (2,000 Hz). Universal motor encoder interfaces and different connection possibilities to a higher-ranking control allow easy adaptation to changing system requirements – paving the way to optimal implementation of multi-axis applications.

Close cooperation during development

SD2 proved its flexibility to EST. "We wanted to adapt the solution to our needs but not re-invent the wheel, so to speak," says Stefan Nuding. "In close cooperation with SIEB & MEYER we were able to fulfill this requirement in the best possible way." EST developed the control board (also called processing card) on their own and integrated the SIEB & MEYER circuit for the device control in the layout. "For this purpose, we developed an individual front end with different interfaces for SD2 that was exactly adapted to the customers needs", Ralph Sawallisch explains. "This way an additional circuit board was not required." As well as in the SD2 standard device, the circuit board is mounted in a common housing with the underlying components. SIEB & MEYER conducts the final tests of the SD2 devices customized for EST by means of a provisional processing card that is removed afterwards. On the premises of EST the final control board is installed.

Robust, reliable and long-term availability

EST CEO Stefan Nuding is very satisfied with SD2. Beside proper functioning, he sees the benefits in the robustness and high availability of the devices. "Our control systems are designed to cope with three-shift operation. SD2 can easily keep up with that." The long product life is an important selling point for EST: The control experts need the assurance that SD2 is not suddenly withdrawn from the market or replaced by an incompatible device – this would cause big problems for many of the end customers. With SIEB & MEYER devices EST is on the safe side because the company continuously develops its devices further rather than replacing them abruptly by a new generation. Therefore, there are no obstacles to a long-term continuation of the good partnership. Stefan Nuding agrees: "The cooperation with SIEB & MEYER couldn't be better. The staff is competent, the reaction times are quick and we can directly communicate with the development engineers, which sadly is a rarity nowadays."


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