A Dörries Contumat vertical turning lathe is playing a key role in the finish machining of a range of separator components being produced by GEA, delivering a high level of process reliability and quality in the production of the modified duplex steel workpieces – and, as a result, the machine has practically eliminated waste and rework.
Supplied by Dörries Scharmann, a Starrag Group company, the Contumat VCE 1600/140 SM S0 VTL is machining ten main components for the separators produced by GEA, a company that specialises in the manufacture of centrifuges used to separate fluids or liquids and solids, and used by dairies and breweries as well as by shipbuilders for the preparation and cleaning of fluids. The company produces around 800 separators a year, generally in batches of one- to three-off.
The centrifuges must meet the stringent requirements set out in hygiene regulations from the European Hygienic Equipment Design Group and the USA’s 3-A Sanitary Standards. To meet these demands, as well as the extremely strict regulations that apply in the food industry, for example, the typical main components must be precisely co-ordinated with one another and offer a precision fit.
A range of the most important components are being finished machined on the Contumat VTL which, with solid cast construction (it can accommodate components weighing nine tonnes), significant drive power (feed force of 35,000 N) and hydrostatic guide, is able to machine the heavy-duty components with a high level of repeatable accuracy. The 3-A Sanitary Standards, for example, stipulate that surfaces in contact with food must demonstrate mean roughness values of Ra ≤ 0.8.
"The finish being achieved by the Contumat is a significant key to our increased productivity," says Antonius Mußhoff, GEA’s project manager for separator production. Coupled with a maximum machining diameter of 1,600 mm, a turning height of 1,200 mm and a table diameter of 1,400 mm, the machine can comfortably accommodate all of GEA’s needs.
Mr Mußhoff adds that the VTL is particularly effective in machining drum bases, one of the most complex components so far machined. As this component is used as a supporting element for all other separator components, a great deal hinges on its level of quality and precision.
“The drum base offers the highest level of quality with the IT6 tolerance grade, which requires parts to demonstrate a position and form tolerance of 20 microns in relation to one another," he explains. "Thanks to the machine’s high reliability, there are practically no instances where rework is required – and we are on our way to achieving 0% wastage."
The Dörries Scharmann Contumat VTL is machining ten main components for GEA’s separators (below)
An aerial view of the Contumat cell at GEA, which produces 800 separators a year