Optimized Machine Assignment Through Virtual Measurement Environment

The blade production of Siemens AG Steam Turbines in Görlitz is the headquarters of Siemens' steam turbine business. Siemens produces industrial steam and gas turbines at eleven locations worldwide, which are supplied as turbo sets or mechanical drives. The turbines and turbo sets developed and produced in Görlitz produce between 45 kW and 250 MW. Around 20,000 Siemens steam turbines are installed worldwide - the majority come from Görlitz.

Every scoop is unique

Virtually none of these 20,000 turbines are the same. Almost every one is unique. "Turbine construction is one-off production," explains Ulrich Maywald, head of turbine blade production at Siemens AG in Görlitz. “Even if two may look alike from the outside, their structure is certainly different in the main details. Because every single turbine is designed according to the customer's individual parameters. The only small series production within turbine construction is blade production."

For the viewer, the blades are undoubtedly the most striking and impressive elements of a turbine. A large-sized turbine can combine up to 200 of them, arranged on ring sets of different sizes. While the small high-pressure blades (HD) are located at the steam inlet of the turbine, these become - towards the rear - with the steam expansion - increasingly larger and increasingly twisted low-pressure blades (LP).

Milled from a forged blank

“Our smallest manufactured HD shovel measures 45 millimeters in height and 12.5 millimeters in width. The largest LP shovel is a proud 1.2 meters long and weighs an impressive 43 kilograms. It is milled from a forged blank that originally weighed 76 kilos,”reports Ulrich Maywald, transferring the complex manufacturing process for the low-pressure blades.

Like the largest to date, all other LP blades with their twisted blade and fir tree-shaped base are made from a forged blank. The most modern CNC five and four-axis machining centers are available for this in Görlitz. “Complete machining takes place on such a machine in two steps. A 95 percent finished shovel is created from the blank,”explains production manager Ulrich Maywald. And adds: “Of course, this vertical range of manufacture is also an enormous challenge for quality assurance. Because we are faced with a large number and very different influencing factors that influence the throughput. This includes set-up and especially measurement times."

Manufacturing and schedule risks

If there are difficulties when starting up an NC program or when measuring a bucket for the first time, the production plan and the scheduling must be quickly adapted. "The use of simulation software significantly reduces the risk of errors in these points," states graduate computer scientist Sebastian Frinker, application engineer in Görlitz blade manufacturing.

In order to be able to carry out a collision check and axis optimization on the milling machines at the same time, it is particularly important for forged blanks to know their exact contour. At Siemens, the blanks are fully digitized using the Romer Absolute Arm 7-Axis SI measuring arm. The generated 3-D model is then used as the starting point directly in the NC programming software of the milling machines.

Content of the article:

• Page 1: Optimized machine assignment through virtual measurement environment
• Page 2: Measure manufacturing results virtually
• Page 3: Instruction using target profiles

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