Oerlikon Barmag AG has increased its productivity by approximately 25% since investing in Hardinge Kellenberger grinding technology. At the same time, the company has reduced lead times by 30%. 

Founded in 1922, the company was and specialises in spinning systems for man-made fibres including polyester, nylon and polypropylene and is part of the multi-billion dollar Oerlikon Sauer Textile Group. The company also manufactures rotational and symmetrical components used in the spinning process and in the production of man-made fibres, including winders, pumps and godets, working with a wide variety of materials, including steel (heat-treated, nitrided, high-tensile and specialty); aluminium, castings and brass.

The company currently has five Kellenberger Kel-Varia grinding machines at its Remscheid facility including two CNC 225/1500s, one CNC 175/1000 with a B-axis, a 225/1500 and a 125/600 for ID/OD work.

Says Andreas Böttcher, Senior Manager of Spinning Machinery: ’Prior to 1999 we were using German grinding technology. However, once we saw the Kellenberger machines in action we knew we needed to up our game in terms of performance and machining accuracy and repeatability. To put it simply, the Kellenberger machines are a superior product.’

Component grinding

The shafts are 1500mm in length and are machined between centres on the Kel-Varia 225/1500s grinders to diameter tolerance of 0.01 mm and cylindrical form of 0.005 mm. The batch size for the winder shafts is 72 components and the grinding time per part is 65 minutes. 

The winder shafts are made from special, non-hardened fine grained steel (20MnV6) and have a changeover time from one batch of winding shafts to another of 45 minutes. 

Another Kel-Varia machine is used to grind the hardened shafts for the godets. The shaft length is 850mm and in a single setup the shaft, two cones, six shaft bases and one plane surface are all machined to an overall diameter tolerance of 0.008mm, cone tolerance of 0.005 mm, cylindrical form of 0.004mm and common zone tolerance of 0.005 mm.

The batch size for the godet shafts is 96 parts, and the grinding time per part is roughly 42 minutes. The material machined for the godet shafts is nitride 42CrMo4V.

Says Böttcher: ‘For this process we use the Kel-Set automatic grinding wheel measuring system for diameter and length. The machine used is a Kel-Varia CNC 175/1000 that has two grinding wheels and an additional B-axis for grinding the cones.

‘I think this kind of very high precision is only possible with the hydrostatic guideways and the exact measuring systems you get on the Kellenberger machines.’

Other advantages of the Kellenberger machines, according to Böttcher include the reduction in scrap, which is now less than 0.5% and the achievement of superior surface finishes negating the need for post-grinding secondary polishing operations that were time consuming and labour intensive.

www.barmag.oerlikontextile.com
www.hardinge.co.uk