Weingärtner’s New Spin on Machining (Source: WWW.DIESELGASTURBINE.COM)
After the successful launch of its MPMC 600 model a few years ago, the Multi Product Machining Center (MPMC) Series of Austrian tooling machine manufacturer Weingärtner Machinenbau has expanded its line to include five models, with the largest being the Series 1500.
The MPMC’s machining length between centers depends on the machine bed that is offered in increments of 1 m. The greater the length between centers, the higher the series of machine bed necessary to handle the parts.
The development of the series is still ongoing, revealed Gerald Steininger, manager of the machine tool division at Weingärtner. He added that a project for the installation of a machine capable of working 26 m-long pieces should be completed at the end of 2009.
Steininger explained that turning milling machines are ideal for machining large crankshafts for marine, locomotive or power generation applications. “MPMC can accommodate parts with a weight of up to 20 metric tons and guarantee powerful five-axis turning and milling operations with high stock removal, required for cutting crankshafts, parts for compressors and turbines, as well as generator bars for power plants,” he said.
Besides the conventional turning milling process, these machines perform a virtually unlimited number of operations including drilling, whirling, peeling, threading, hobbing, polishing, grinding and measuring, among others.
“The MPMCs are capable of dealing with the whole process of crankshaft machining from raw material to final balancing, although most customers prefer to perform the first pre-machining of the raw material themselves, then move on to the more sophisticated MPMC for the main tasks,” said Steininger. “However, the weight and length of the parts to be machined are not the only challenging factors for these machines. Sometimes the smallness of tolerances can be the most impressive,” he added. “Such tolerances, which are already difficult to handle in small parts, become a real challenge with pieces that weigh several tons.”
This is the reason that the design and stiffness of the machine are critical aspects to accomplish the required precision. Furthermore, the MPMC features steady rests that are positioned-controlled in three axes to ensure that the shaft remains clamped in the correct position.
In-process measuring is a key element to ensure the precision of the process and that the machines routinely measure the workpiece and the tool before any finishing pass.
The core of the MPMC is the turning/ milling center. However, an important role is played by the automatic tool charger, which moves on an independent shuttle and operates simultaneously during the machining process. The charger can accommodate up to 180 different tools. Tool changes take only three seconds and can take place in any longitudinal travel position.
As for the software and control part, the WeinCAD software package, provided by Weingärtner, generates the program for the part machining and transmits it to the Siemens 840D control, which manages the process. Finally, the diagnostic program WMDS, in combination with emulation software CHECKitB4, completes the package to ensure maximum productivity.