Leading development partner for the transportation sector EDAG (Detroit, MI / Fulda, Germany) recently had to come up with a heavy-duty ring for a new production concept. EDAG employs over 5,600 people globally. The WEISS CR2600 heavy duty ring rotary table, with its noticeably wide center opening, is a rare instance of a traditional rotary table and shuttle system for a workpiece of this size that allows robot access from both sides.
The system, designed for small lot production of vehicle components, was required to not only bear the weight of car body tools weighing up to four tons, but also provide sufficient room at its center for a heavy-duty robot.
During the early phases of development, EDAG engineers discovered that the heavy-duty rings currently on the market were insufficient to support the weight of four large, heavy vehicle body tools while still allowing enough space for handling systems and a robot inside the ring, not simply on the outside. Manfred Hahl, Managing Director/COO of EDAG, moved quickly to find a solution to the new manufacturing idea that would ultimately offer its clients cost savings and innovation that would improve quality.
In order to build a comprehensive, integrated solution for EDAG’s specific manufacturing system, Hahl hired WEISS North America, Inc. (Willoughby, OH), and its parent company WEISS (Buchen, Germany), a top specialist in the industry for rotary tables and automation.
WEISS North America started developing the custom technical specifications for a special CR2600 rotary table based on its robust CR series line of heavy-duty rings, which have big open cores. This table could ultimately fit four tools and a robot in the middle.
ROUNDING OUT THE SPECS
Key specifications for the new CR2600 heavy duty ring table quickly came into focus:
- A permissible vertical axial 500kN dynamic and 1000kN static force on the drive plate
- A central opening of two meters and a freely programmable drive
- A low installation height of only 300 millimeters to enable stepless, ergonomically favorable manual loading alongside automatic loading
- Implementing WEISS Application Software (WAS) to ensure fast set-up and uncomplicated integration into all production cycles
A flat design, zero backlash, optimal power transmission, a drive unit placed far to the outside that can be quickly put into operation with WAS, and other favorable design traits of the WEISS CR series would also be inherited by the new member of the family.
According to Stanislav Cafuta, a WEISS system developer, “The key was designing the ring’s central opening with a diameter of two meters, tool weights of up to 20 tons, and a reach of up to 2.5 meters – demands which even our largest heavy-duty rings were unable to meet at the time.”
BEARING A TECHNICAL HURDLE
The new-generation CR2600 had to overcome a number of technical obstacles in order to meet its production targets. WEISS was able to monitor and assure quality while more quickly acquiring massive parts with lengthy delivery times thanks to its extremely high vertical integration rate.
A crucial component among these was the bearing. It takes a long time to build a so-called YRT bearing, which combines two axial bearings with a radial bearing. The WEISS engineers opted to speed up the process by delegating responsibility for the creation of the bearing cages themselves to bearing supplier Schaeffler (Fort Mill, SC), in order to resolve this issue. As a result, the new CR2600 heavy duty ring table’s development and delivery times were shortened to six months.
CR2600 HEAVY DUTY RING TABLE CONCLUSION / RESULTS
Featuring a distinctly large central opening, the CR2600 heavy duty ring table is a unique combination for this size of a classic rotary table and shuttle system in which robots can access the workpiece from both sides. The system is currently running with two tools for two components, so that the rear hatches and bonnets can be manufactured in a combined process.