October 2019

40 n MACHINE BUILDING October 2019 www.drivesncontrols.com Cutting metal pipes cleanly to order A German manufacturer of pipe-cutting machinery has turned to servodrives with built-in motion control and graphical programming capabilities for a new machine that cuts cleanly through metal pipes of varying sizes and materials. T he German machine-builder, FZH Maschinenbau, specialises in equipment that cuts lengths of metal pipe precisely for various mechanical engineering applications, especially in the automotive industry. The cut pipe edges need to be free of shavings with hardly any burrs. FZH’s Vario pipe-cutting system is designed for pipes with diameters from 4–120mm and wall thicknesses from 0.1–2.5mm (or 1.5mm in the case of stainless steel). The machine can handle pipes made of different alloys, and does not need any coolants or lubricants. The first element of the cutting machine is a drummagazine, which serves as a buffer for blanks. Next, a servo-motor-driven handling systemwith tilting and linear axes automates the feeding of the cutting equipment. The focal point of the process is the cutting head. A linear axis with a gripper places the pipe to be cut in the middle of the cutting head. A laser-etched mark indicates where three circular blades will make contact with the surface. The mark is detected by an optical sensor integrated into the cutting head. Two servodrives combine to actuate the cutting head. A supporting disk moves the three circular cutting blades, at a defined rotational speed, along the outer edge of the pipe to be cut. A cam-controlled disk axis then lowers the blades towards the material with a precisely defined profile and opens the cutter wheels. To help design the drive and control technology needed for its cutting machine, FZH turned to experts at Quality Automation (QA), which it appointed to implement the machine’s automation functions.“We were responsible for the electrical design, for CE documentation, for building the control cabinet, for software development and, ultimately, for commissioning the equipment too,”explains Friedhelm Steffens, a member of QA’s management team. He points out that the cam-controlled feed and opening motion for the cutter wheels “offers clear advantages compared with conventional cutting processes. First of all, the cutting blades approach the pipe at considerable speed. As they cut through the pipe, they slow down, without actually stopping, until they reach the end position. They then return to their original position, but again at speed. “The process is a clean one,”Steffens adds. “The flexibility of the motion control solution makes it possible to adjust the cutting head to new pipe cross-sections or different materials, almost at the push of a button. Formulations can be selected from the control panel. Individual adjustments can also be made here to things like feed speed.” Built-in flexibility When designing the machine and its control system, the aimwas also to automate the cutting head movements in such a way that it could be used for pipes with various cross- sections, wall thicknesses and materials.“It is important to ensure flexibility so different types of orders, including small runs, can be produced economically,”Steffens points out. This machines are coordinated and controlled by Kollmorgen AKD PDMM servodrives which incorporate programmable motion control functions. These drive the lever-type supporting disks and control other Kollmorgen AKD servo controllers via EtherCat. They also communicate via Profinet with a Siemens control system, which acts as a Profinet master. QA set up the motion sequences and the synchronisation of the drives using Kollmorgen’s Automation Suite (KAS) development platform, which is integrated into the AKD PDMM. The servo amplifier has both The pipe-cutting machine (on the left) is fed with blanks from the drum magazine (on the right), which serves as a buffer for the blanks

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