TPT May 2013

Article

A study of a pipe manufacturer replacing conventional hydraulic controllers with technology controllers By Andreas Diepgen and Bernhard Brehm, Siemens

“Where other metalforming machine tools leave off, we are just getting warmed up,” says Erich Büchele, getting right to the point about the subject that his company, Erich Büchele Maschinenbau GmbH (Ebm) in Meitingen (near Augsburg), is concerned with: This is in reference to the know-how, capabilities and resources for the development and production of standard and special machines (Figure 1) for the individual processing of pipes/pipe ends (Figure 4). Customers feel “at home” with Ebm, especially in situations where contours, tolerances, materials or even the processes go beyond the usual requirements (see box). With this attitude, the Swabians have grown from a small-scale, garage-based operation to the (technology leader and) equipper of worldwide companies in fewer than 25 years. Thus, for example, tubing which has been processed on Ebm machines is now used in a large percentage of the cars on our streets. The proximity to the automotive industry is another reason why the mid- sized company prefers standardised Siemens automation technology, which is well-known, available and accepted around the world. Therefore, the use of Simatic controllers in a wide variety of designs has always been a “given”. Motion control in the PLC Since the beginning, Ebm has used the latest Simatic Technology Controllers in its machines, which combine both PLC, motion control and even a large number of technology tasks that can be programmed in Step 7. Currently, the variants CPU 315T2 DP (Figure 2) and CPU 317T2 DP (for up to 8 or 32 axes) are available along with the CPU 317TF2 DP, which, in addition to the technological functionality, also has Safety Integrated on board. The technology functionality of this controller is contained in preconfigured, PLCopen- conformant function blocks, which are integrated into the engineering system Step 7 via the Simatic S7 Technology options package and linked together as needed. This is done as with standard Simatic function blocks so that it is not necessary to learn a new motion control language. The machine manufacturer previously used the 315T and 317T for position-controlled positioning or coupling of electric drive axes. This allows complex, synchronised motion sequences such as gearing and curve synchronisation, where the synchronous axes can be coupled to a virtual or real master, to be implemented at a comparatively low cost. Communication with the drive is implemented via the isochronously operating Profibus DP(Drive) interface of the controller.

A technology controller with comprehensive hydraulic functions eliminates the need for a separate hydraulic controller and allows integrated remote servicing of all components for the first time. Ebm, a leading manufacturer of standard and special machines for the individual processing of tubes, can now control all of the processes of its pipe end processing systems using the technology controllers. It uses it to automatically linearise the characteristic curves of proportional directional control valves and regulates and limits pressures with extreme precision, optimising not just the process, but also the costs. Even all of the required safety functions can be integrated as needed. In mechanical engineering, the products range from manual or even automatically operated standard machines to the planning, development, design and production of customer-specific special machines. In cooperation with competent, long-standing partners, Ebm implements individual complete solutions up to and including fully automated production lines. The entire manufacturing process, from the supply of materials to the shaped, fitted, labelled and measured ready-to- install part can be shown on one system. In addition to mechanical engineering, Ebm provides support to its customers by means of machine-specific training courses, spare parts service, and individual optimisation consulting. Ebm Maschinenbau was founded in 1987 by Erich Büchele in his garage. Pursuing the consistent goal of offering low-cost but high-quality machines in the area of axial reshaping – a vacant niche in the market at the time – the one-man business changed against the backdrop of its flourishing order business into a limited liability corporation, with the plant in Herbertshofen in 1988. Thanks to continuous growth and good contacts with the USA, the subsidiary Ebm America Inc was founded in 1993 in Spartanburg, South Carolina, and an exhaustive network of representatives was established in the northern USA. Meanwhile, Ebm employs more than 50 people, who are successfully expanding and developing the company and allowing it to grow and establish itself in Europe and in the USA as a competent and user-friendly supplier of a wide range of pipe shaping systems.

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May 2013