Rotary Table, Transfer Center, or CNC Unit

For machinery producers, it is always a rather special design challenge when manufacturers are seeking an optimum solution for a series production job. Possible choices include rotary table systems, transfer centers, or CNC units. At the EMO trade show in Hannover, Germany from September 16 - 21, 2013, there will be an abundance of solutions on show, not least from MA G, Göppingen, and the Swiss Starrag Group.

“A line’s useful lifetime is 20 years, but a work piece lasts for only seven: this means the production system is going to see at least three generations of components,” says Dr. Manfred Berger, president automotive Europe at MAG Europe GmbH from Göppingen.

The company meets these requirements from its customers for today’s production systems in most cases with versatile manufacturing systems based on single and twin-spindle CNC units, which, Berger says, “are commonly, but incorrectly, referred to as machining centers.”

The CNC Unit Dominates
At MAG, the CNC units continue to dominate, accounting for about 90% of machinery sales. When difficult components are involved, specialized machines are used.

“The trend nowadays is definitely towards aluminum work- pieces for cars, and thus lighter metal-cutting with CNC units,” the expert explains. “We make particular use of transfer machines in cases where work- pieces of grey cast iron have to be produced in very large quantities.” 

For these components (batch size >600,000 a year) and aluminum work pieces (> one million a year) with limited part diversity, he adds, not only transfer lines but also rotary machines operate very efficiently with high levels of productivity. Transfer centers are specialized solutions, offering a high level of productivity thanks to their multiple-spindle design, coupled with the flexibility of a travelling device. Drill heads and devices can be easily changed over. 

To quote Berger, “Transfer centers thus marry the productivity of a transfer machine to the flexibility of a CNC unit. They are ideally suited for use with high work piece volumes and limited part diversity.”

However, what will visitors to the EMO Hannover 2013 see on MAG’s stand, what “machine variant” will be showcased? Berger is unable and unwilling to divulge any details, but he is at least prepared to reveal some trends.

“Within the framework of our “Intelligent investment – efficient production” initiative, we shall at the EMO Hannover 2013 also be progressing the in-depth efficacy of our foresightful corporate planning, our capital investment for more flexibility in terms of volume, work pieces and technology, plus the use of sleeping reserves in production lines by tapping into better personnel skilling,” Berger states.

A Chemnitz-based company approaches the issue from a different viewpoint. “Within the Starrag Group, and in particular at Heckert, we have not focused our product strategy solely on large-series business,” comments Dr. Eberhard Schoppe, managing director of Heckert GmbH from Chemnitz (a member of the Swiss Starrag Group). “For us, the primary focus has always been on the flexibility of the manufacturing concepts involved, driven by our technical solutions.”

When it comes to choosing the right production concept, however, the machine buyer is spoiled for choice.

“In the context of our production solutions, with the ongoing trend towards automation and maintaining a high degree of flexibility, what we see emerging is a focus on systems for pallet storage and overhead transfer,” Schoppe observes. “The increasing product variance at our customers ultimately results in a shrinking series character, and a rising need for automation solutions featuring pallet storage systems.” 

When it comes to manufacturing large series, says Schoppe, about one in four of Heckert’s machines have for this reason already been fitted with a linear pallet magazine.

The company from Chemnitz prioritizes concatenated solutions featuring individual machines. The firm’s Managing Director sees concatenated configurations with pallet systems as an attractive option when a high diversity of work pieces and devices is involved. “The primary advantage is the flexibility,” explains the expert. “In operator-free times, a large workload of highly disparate production jobs can be run.” The user, however, can also enter new machining tasks in the line at any time – usually on a main-time-parallel basis. Machining is performed in an order-referenced sequence, and can be organized using a priority control feature.

Concatenations with Direct Workpiece Handling
In the case of large series with a low diversity of work pieces and clamp settings, by contrast, concatenations with direct work piece handling are the dominant choice.

“The advantages here lie in the cost savings for machine pallets, devices and production footprint,” Schoppe says. “The line has been specially and meticulously designed to suit the small number of machining jobs involved, which means it is relatively affordable and highly effective.” 

Heckert’s flexible production lines have also proved efficacious in the global automotive industry.

“A multiple-machine concatenation with a pallet size of 630 has for ten years now been used for producing 8- to 12-cylinder crank- cases for V engines in 5-axis complete-machining mode. This demonstrates the flexibility and long-term accuracy of our flexible production systems,” Schoppe says.

How is Heckert going to build on its successes with concatenated individual lines, and what may we expect to see on the Starrag Group’s stand at the EMO Hannover 2013?

Schoppe looks into the future: “I see two trends: complete machining based on process integration and 5-axis machining, plus a reduced number of clamping positions.”

For more information about EMO, please contact: Donna Hyland at Hannover Fairs USA at +1 (908) 735-0559 or dhyland@hfusa.com. 

About EMO Hannover 2013
From September 16 to 21, 2013, international manufacturers of production technology will be spotlighting “Intelligence in Production” at the EMO Hannover 2013. The world’s premier trade fair for the metalworking industry will be showcasing the entire bandwidth of today’s most sophisticated metalworking technology, which is the heart of every industrial production process. The fair will be presenting the latest machines, plus efficient technical solutions, product-supportive services, sustainability in the production process, and much, much more. The principal focus of the EMO Hannover is on metal-cutting and forming machine tools, production systems, high- precision tools, automated material flows, computer technology, industrial electronics, and accessories. The trade visitors to the EMO come from all major sectors of industry, such as machinery and plant manufacturers, the automotive industry and its component suppliers, the aerospace sector, precision mechanics and optics, shipbuilding, medical technology, tool and die manufacture, steel and lightweight construction. The EMO Hannover is the world’s most important international meeting point for production technology specialists from all over the planet. In 2011, the fair attracted more than 2,000 exhibitors, and around 140,000 trade visitors from more than 100 different countries. EMO is a registered trademark of the European Committee for Cooperation of the Machine Tool Industry CECIMO.