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Need flexibility in a lean environment? Try producing all components in-house. That's a practice followed by Farmington, Conn.-based TRUMPF Inc. The company sought a better way to produce the high-precision components of their lasers, fabricating machine structures and related assemblies.
For many machined components, which range in material composition from aluminum alloys to mild steel, tool steel and stainless, the work was previously performed on a series of horizontal machining centers and a stand-alone five-axis milling machine at the company's Farmington facility, says components manager Peter Hafner.
For machined components, the company uses two DMG five-axis universal machining centers, equipped with twin rotating pallets and a Fastems automated loading system, powered by Siemens CNCs. Implementing two five-axis machines replaced the HMCs and allowed the company to transfer 70 percent of the work from the stand-alone mill, to keep "production running in a more streamlined manner," says Kai Moellendorf, director of manufacturing.
On one laser resonator frame, which holds the resonator in position, accuracy is paramount. Measuring 23.6 square inches and 4.7 inches high, the frame requires eight holes with true position of 0.0016 inch with a 0.39 inch H7 diameter and 0.39 inch depth. The parallelism and perpendicularity on eight surfaces of the frame must be within a 0.0008 inch tolerance.
The two DMG model DMC 100 U duoBlock machining centers machine various other steel and aluminum housings. A twin-pallet system on each allows the loading and unloading of a fixtured workpiece by the Fastems automated system, while the machines are making chips. Each is equipped with an automatic tool changer and an additional 240-position tool magazine. And each tool has a data tag/chip that contains all information required to identify the tool and its properties, including length, diameter, tool number and other characteristics.
Controlling all axes, tool changes and pallet movements on each machining center is a Siemens Sinumerik 840D Powerline CNC with Simodrive 611D drive package. The PCU has a video link to the operator terminal.
Hafner comments that the tool identification chips are read by a sensor before entering the machine magazine, providing an additional safeguard against the wrong tool entering the work area. The company's goal is 24/7 operation of these machining centers within one year.
The CNC uses proprietary DMG interface software, as well as the Siemens ShopMill suite, with Ethernet communication of all machine condition status to the internal TRUMPF server for production monitoring. Throughout the facility, performance data are displayed for all to see.
Typically, parts are designed by TRUMPF engineers with the CAD software SolidWorks, then fed into the CAM software TOPCAM, where the NC files are created. These files are then transferred to the machining centers via Ethernet connection.
Hafner says machine control required careful attention. "With five-axis, spindle and ancillary motion control involved, the CNC and drive package needed to be very adaptable to our numerous short runs, varying sizes, extremely tight tolerances and expansive tool handling requirements ... [and] the extra demand of integrating the Fastems pallet-changing system was critical, both in terms of speed and reliable delivery of the correct workpieces to the two machining centers."
DMG wrote the software to integrate the pallet system with the two machining centers, working with Siemens hardware and the Fastems controller.
Editor's Note: Kai Moellendorf, Peter Hafner, Edin Meskic, Michael Reuster and Catherine Flynn of TRUMPF, Daniel Wetterkamp of DMG and Lucjan Geissler of Siemens all contributed to this story.