Cable Car Extremes

Doppelmayr relies on bridge-type measuring machine from Carl Zeiss

With an ACCURA bridge-type measuring machine from Carl Zeiss, the global market leader intends to further enhance the precision of its cable car systems and anchor in its corporate culture the company's ambition to deliver 100 percent quality.

Chairlifts for eight, strong wind gusts and operating heights hundreds of meters up in the air: Doppelmayr experiences the extremes of skiing in its everyday business. This is also true of the gigantic components built in Wolfurt, Austria. The center part of the large drive pulleys that guide the cable around the stations at the top and bottom of the mountain tips the scale at around two tons. They are surrounded by four wing segments.

In the manufacture of such parts, maximum precision down to a hundredth of a millimeter is vital. A deviation from the ideal dimensions does not necessarily represent a safety risk; however, even the harmless failure of a cable car can cost the operators millions in revenue. Precision for the center of the pulley means deviation of no more than 50 micrometers from the ideal form. If this tolerance is exceeded, the connecting plates for the wing elements do not seamlessly line up with the center part. Furthermore, the ball bearings in the center must be positioned with absolute concentricity; otherwise friction leads to excessive wear on the parts and possible system failure. Reliable quality assurance has therefore always been a top priority at Doppelmayr. An ACCURA II bridge-type measuring machine from Carl Zeiss has been a key element of this process since August 2011. With dimensions of 2000 x 3000 x 1500 millimeters, it is one of the largest bridge-type machines ever sold in Austria by Carl Zeiss.

A measuring machine for the future

Zündel opted for Carl Zeiss due to the company's good reputation and closeness of the Austrian subsidiary which ensures short reaction times if a problem should ever arise: "We are in contact with our customers around the clock. As a customer, we demand the same service," adds Zündel. Furthermore, it was important to Zündel for the measuring equipment to include software or optical sensors, if necessary.

Four to fives times higher accuracy

Doppelmayr is already using the ACCURA to measure 100 percent of all safety-relevant parts. The measuring machine scans the center part and the pulley in one full CNC run. It compares the position of every borehole with the nominal geometry, checks all dimensions of the four machined surfaces and measures the turned cylinder borehole in the center. CALYPSO software then automatically generates the measuring log.

Additional benefits: the labor needed for measurements has been drastically reduced and the precision is four to five times higher. Furthermore, CALYPSO measuring software exports clearly structured documentation of the results at the push of a button.

"Once I generate a measuring program for a workpiece, the machine does everything automatically even if I have to measure 200 parts," says a satisfied Roland Schedler who works in quality assurance at Doppelmayr.

100 percent Quality

But, accuracy is not everything to Karl-Heinz Zündel: "With this particularly precise measuring machine, we also want to impress upon our entire team that we have to deliver 100 percent quality in everything we do."

The measuring machine is already being fully utilized – and the company is considering acquiring a second system. However, a larger measuring lab is needed first.

About the company

The Doppelmayr Group, the global market leader in cable car systems, has its main factories in Wolfurt, Austria, and Goldau, Switzerland. Its products include three-cable systems in which up to 30 passengers hover above the valley below. The company's 2,200 employees generated annual revenue of around 618 million euros with this business in 2011.